Patent Abstract:
An alloy composition of the formula Fe a B b Si c P x Cu z . Parameters meet the following conditions: 79≦a≦86 atomic %; 5≦b≦13 atomic %; 0&lt;c≦1 atomic %; 1≦x≦8 atomic %; 0.4≦z≦1.4 atomic %; and 0.08≦z/x≦0.8.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a divisional of U.S. application Ser. No. 12/544,506, filed Aug. 20, 2009. The entire disclosure of the prior application, application Ser. No. 12/544,506 is herewith incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to an Fe-based nano-crystalline alloy and a forming method thereof, wherein the Fe-based nano-crystalline alloy is suitable for use in a transformer, an inductor, a magnetic core included in a motor, or the like. 
         [0003]    Use of nonmetallic elements such as Nb for obtaining a nano-crystalline alloy causes a problem that saturation magnetic flux density of the nano-crystalline alloy is lowered. Increase of Fe content and decrease of nonmetallic elements such as Nb ca provide increased saturation magnetic flux density of the nano-crystalline alloy but causes another problem that crystalline particles becomes rough. JP-A 2007-270271 discloses an Fe-based nano-crystalline alloy which can solve the above-mentioned problems. 
         [0004]    However, the Fe-based nano-crystalline alloy of JP-A 2007-270271 has large magnetostriction of 14×10 −6  and low magnetic permeability. In addition, because large amount of crystal is crystallized while being rapidly cooled, the Fe-based nano-crystalline alloy of JP-A 2007-270271 has poor toughness. 
       SUMMARY OF THE INVENTION 
       [0005]    It is therefore an object of the present invention to provide an Fe-based nano-crystalline alloy, which has high saturation magnetic flux density and high magnetic permeability, and a method of forming the Fe-based nano-crystalline alloy. 
         [0006]    As a result of diligent study, the present inventor has found that a specific alloy composition can be used as a starting material for obtaining an Fe-based nano-crystalline alloy which has high saturation magnetic flux density and high magnetic permeability, wherein the specific alloy composition is represented by a predetermined composition and has an amorphous phase as a main phase and superior toughness. The specific alloy is exposed to a heat treatment so that nanocrystals consisting of bccFe phase can be crystallized. The nanocrystals can remarkably degrease saturation magnetostriction of the Fe-based nano-crystalline alloy. The degreased saturation magnetostriction can provide higher saturation magnetic flux density and higher magnetic permeability. Thus, the specific alloy composition is a useful material as a starting material for obtaining the Fe-based nano-crystalline alloy which has high saturation magnetic flux density and high magnetic permeability. 
         [0007]    One aspect of the present invention provides, as a useful starting material for an Fe-based nano-crystalline alloy, an alloy composition of Fe a B b Si c P x C y Cu z , where 79≦a≦86 atomic %, 5≦b≦13 atomic %, 0&lt;c≦8 atomic %, 1≦x≦8 atomic %, 0≦y≦5 atomic %, 0.4≦z≦1.4 atomic %, and 0.08≦z/x≦0.8. 
         [0008]    Another aspect of the present invention provides, as a useful starting material for an Fe-based nano-crystalline alloy, an alloy composition of Fe a B b Si c P x C y Cu z , where 81≦a≦86 atomic %, 6≦b≦10 atomic %, 2≦c≦8 atomic %, 2≦x≦5 atomic %, 0≦y≦4 atomic %, 0.4≦z≦1.4 atomic %, and 0.08≦z/x≦0.8. 
         [0009]    The Fe-based nano-crystalline alloy, which is formed by using one of the aforementioned alloy compositions as a starting material, has low saturation magnetostriction so as to have higher saturation magnetic flux density and higher magnetic permeability. 
         [0010]    An appreciation of the objectives of the present invention and a more complete understanding of its structure may be had by studying the following description of the preferred embodiment and by referring to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a view showing relations between coercivity Hc and heat-treatment temperature for examples of the present invention and comparative examples. 
           [0012]      FIG. 2  is a set of copies of high-resolution TEM images of a comparative example, wherein the left shows an image for a pre-heat-treatment state, and the right shows an image for a post-heat-treatment. 
           [0013]      FIG. 3  is a set of copies of high-resolution TEM images of an example of the present invention, wherein the left shows an image for a pre-heat-treatment state, and the right shows an image for a post-heat-treatment. 
           [0014]      FIG. 4  is a view showing DSC profiles of examples of the present invention and DSC profiles of comparative examples. 
       
    
    
       [0015]    While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. 
       DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0016]    An alloy composition according to an embodiment of the present invention is suitable for a starting material of an Fe-based nano-crystalline alloy and is of Fe a B b Si c P x C y Cu z , where 79≦a≦86 atomic %, 5≦b≦13 atomic %, 0≦c≦8 atomic %, 1≦x≦8 atomic %, 0≦y≦5 atomic %, 0.4≦z≦1.4 atomic %, and 0.08≦z/x≦0.8. Fe may be replaced with at least one element selected from the group consisting of Ti, Zr, Hf, Nb, Ta, Mo, W, Cr, Co, Ni, Al, Mn, Ag, Zn, Sn, As, Sb, Bi, Y, N, O and rare-earth elements at 3 atomic % or less. 
         [0017]    In the above alloy composition, the Fe element is a principal component and an essential element to provide magnetism. It is basically preferable that the Fe content is high for increase of saturation magnetic flux density and for reduction of material costs. If the Fe content is less than 79 atomic %, desirable saturation magnetic flux density cannot be obtained. If the Fe content is more than 86, it becomes difficult to form the amorphous phase under a rapid cooling condition so that crystalline particle diameters have various sizes or becomes rough. In other words, homogeneous nano-crystalline structures cannot be obtained so that the alloy composition has degraded soft magnetic properties. Accordingly, it is desirable that the Fe content is in a range of from 79 atomic % to 86 atomic %. In particular, if saturation magnetic flux density of 1.7 T or more is required, it is preferable that the Fe content is 81 atomic % or more. 
         [0018]    In the above alloy composition, the B element is an essential element to form an amorphous phase. If the B content is less than 5 atomic %, it becomes difficult to form the amorphous phase under the rapid cooling condition. If the B content is more than 13 atomic %, ΔT is reduced, and homogeneous nano-crystalline structures cannot be obtained so that the alloy composition has degraded soft magnetic properties. Accordingly, it is desirable that the B content is in a range of from 5 atomic % to 13 atomic %. In particular, if the alloy composition is required to have its low melting point for mass-producing thereof, it is preferable that the B content is 10 atomic % or less. 
         [0019]    In the above alloy composition, the Si element is an essential element to form an amorphous phase. The Si element contributes to stabilization of nanocrystals upon nano-crystallization. If the alloy composition does not include the Si element, the capability of forming an amorphous phase is lowered, and homogeneous nano-crystalline structures cannot be obtained so that the alloy composition has degraded soft magnetic properties. If the Si content is more than 8 atomic % or more, saturation magnetic flux density and the capability of forming an amorphous phase are lowered, and the alloy composition has degraded soft magnetic properties. Accordingly, it is desirable that the Si content is 8 atomic % or less (excluding zero). Especially, if the Si content is 2 atomic % or more, the capability of forming an amorphous phase is improved so as to stably form a continuous strip, and ΔT is increased so that homogeneous nanocrystals can be obtained. 
         [0020]    In the above alloy composition, the P element is an essential element to form an amorphous phase. In this embodiment, a combination of the B element, the Si element and the P element is used to improve the capability of forming an amorphous phase and the stability of nanocrystals, in comparison with a case where only one of the B element, the Si element and the P element is used. If the P content is 1 atomic % or less, it becomes difficult to form the amorphous phase under the rapid cooling condition. If the P content is 8 atomic % or more, saturation magnetic flux density is lowered, and the alloy composition has degraded soft magnetic properties. Accordingly, it is desirable that the P content is in a range of from 1 atomic % to 8 atomic %. Especially, if the P content is in a range of from 2 atomic % to 5 atomic %, the capability of forming an amorphous phase is improved so as to stably form a continuous strip. 
         [0021]    In the above alloy composition, the C element is an element to form an amorphous phase. In this embodiment, a combination of the B element, the Si element, the P element and the C element is used to improve the capability of forming an amorphous phase and the stability of nanocrystals, in comparison with a case where only one of the B element, the Si element, the P element and the C element is used. Because the C element is inexpensive, addition of the C element decreases the content of the other metalloids so that the total material cost is reduced. If the C content becomes 5 atomic % or more, the alloy composition becomes brittle, and the alloy composition has degraded soft magnetic properties. Accordingly, it is desirable that the C content is 5 atomic % or less. Especially, if the C content is 4 atomic % or less, various compositions due to partial evaporation of the C element upon fusion can be reduced. 
         [0022]    In the above alloy composition, the Cu element is an essential element to contribute to nano-crystallization. It should be noted here that It is unknown before the present invention that the combination of the Cu element with the Si element, the B element and the P element or the combination of the Cu element with the Si element, the B element, the P element and the C element can contribute to nano-crystallization. Also, it should be noted here that the Cu element is basically expensive and, if the Fe content is 81 atomic % or more, causes the alloy composition to be easy to be brittle or be oxidized. If the Cu content is 0.4 atomic % or less, nano-crystallization becomes difficult. If the Cu content is 1.4 atomic % or more, a precursor of an amorphous phase becomes so heterogeneous that homogeneous nano-crystalline structures cannot be obtained upon the formation of the Fe-based nano-crystallization alloy, and the alloy composition has degraded soft magnetic properties. Accordingly, it is desirable that the Cu content is in a range of from 0.4 atomic % to 1.4 atomic %. In particular, it is preferable that the Cu content is 1.1 atomic % or less, in consideration of brittleness and oxidization of the alloy composition. 
         [0023]    There is a large attraction force between P atom and Cu atom. Therefore, if the alloy composition includes a specific ratio of the P element and the Cu element, clusters are formed therein to have a size of 10 nm or smaller so that the nano-size clusters cause bccFe crystals to have microstructures upon the formation of the Fe-based nano-crystalline alloy. More specifically, the Fe-based nano-crystalline alloy according to the present embodiment includes bccFe crystals which have an average particle diameter of 25 nm or smaller. In this embodiment, the specific ratio (z/x) of the Cu content (z) to the P content (x) is in a range of from 0.08 to 0.8. If the ratio z/x is out of the range, homogeneous nano-crystalline structures cannot be obtained so that the alloy composition cannot have superior soft magnetic properties. It is preferable that the specific ratio (z/x) is in a range of from 0.08 to 0.55, in consideration of brittleness and oxidization of the alloy composition. 
         [0024]    The alloy composition according to the present embodiment may have various shapes. For example, the alloy composition may have a continuous strip shape or may be formed in a powder form. The continuous strip shape of the alloy composition may be formed by using a conventional formation apparatus such as a single roll formation apparatus or a double roll formation apparatus, which are used to form an Fe-based amorphous strip or the like. The powder form of the alloy composition may be formed in a water atomization method or a gas atomization method or may be formed by crushing a strip of the alloy composition. 
         [0025]    Especially, it is preferable that the alloy composition of the continuous strip shape is capable of being flat on itself when being subjected to a 180 degree bend test under a pre-heat-treatment condition, in consideration of a high toughness requirement. The 180 degree bend test is a test for evaluating toughness, wherein a sample is bent so that the angle of bend is 180 degree and the radius of bend is zero. As a result of the 180 degree bend test, a sample is flat on itself (O) or is broken (X). In an evaluation described afterwards, a strip sample of 3 cm length is bent at its center, and it is checked whether the strip sample is flat on itself (O) or is broken (X). 
         [0026]    The alloy composition according to the present embodiment is molded to form a magnetic core such as a wound core, a laminated core or a dust core. The use of the thus-formed magnetic core can provide a component such as a transformer, an inductor, a motor or a generator. 
         [0027]    The alloy composition according to the present embodiment has an amorphous phase as a main phase. Therefore, when the alloy composition is subjected to a heat treatment under an inert atmosphere such as an Ar-gas atmosphere, the alloy composition is crystallized at two times or more. A temperature at which first crystallization starts is defined as “first crystallization start temperature (T x1 )”, and another temperature at which second crystallization starts is defined as “second crystallization start temperature (T x2 )”. In addition, a temperature difference ΔT=T x2 −T x1  is between the first crystallization start temperature (T x1 ) and the second crystallization start temperature (T x2 ). Simple terms “crystallization start temperature” means the first crystallization start temperature (T x1 ). These crystallization temperatures can be evaluated through a heat analysis which is carried out by using a differential scanning calorimetry (DSC) apparatus under the condition that a temperature increase rate is about 40° C. per minute. 
         [0028]    The alloy composition according to the present embodiment is exposed to a heat treatment under the condition that a temperature increase rate is 100° C. or more per minute and the condition that a process temperature is not lower than the crystallization start temperature, i.e. the first crystallization start temperature, so that the Fe-based nano-crystalline alloy according to the present embodiment can be obtained. In order to obtain homogeneous nano-crystalline structures upon the formation of the Fe-based nano-crystallization alloy, it is preferable that the difference ΔT between the first crystallization start temperature (T x1 ) and the second crystallization start temperature (T x2 ) of the alloy composition is in a range of 100° C. to 200° C. 
         [0029]    The thus-obtained Fe-based nano-crystalline alloy according to the present embodiment has high magnetic permeability of 10,000 or more and high saturation magnetic flux density of 1.65 T or more. Especially, selections of the P content (x), the Cu content (z) and the specific ratio (z/x) as well as heat treatment conditions can control the amount of nanocrystals so as to reduce its saturation magnetostriction. For prevention of deterioration of soft magnetic properties, it is desirable that its saturation magnetostriction is 10×10 −6  or less. Furthermore, in order to obtain high magnetic permeability of 20,000 or more, its saturation magnetostriction is 5×10 −6  or less. 
         [0030]    By using the Fe-based nano-crystalline alloy according to the present embodiment, a magnetic core such as a wound core, a laminated core or a dust core can be formed. The use of the thus-formed magnetic core can provide a component such as a transformer, an inductor, a motor or a generator. 
         [0031]    An embodiment of the present invention will be described below in further detail with reference to several examples. 
       Examples 1-46 and Comparative Examples 1-22 
       [0032]    Materials were respectively weighed so as to provide alloy compositions of Examples 1-46 of the present invention and Comparative Examples 1-22 as listed in Tables 1 to 7 below and were arc melted. The melted alloy compositions were processed by the single-roll liquid quenching method under the atmosphere so as to produce continuous strips which have various thicknesses, a width of about 3 mm and a length of about 5 to 15 m. For each of the continuous strip of the alloy compositions, phase identification was carried out through the X-ray diffraction method. Their first crystallization start temperatures and their second crystallization start temperatures were evaluated by using a differential scanning calorimetory (DSC). In addition, the alloy compositions of Examples 1-46 and Comparative Examples 1-22 were exposed to heat treatment processes which were carried out under the heat treatment conditions listed in Tables 8 to 14. Saturation magnetic flux density Bs of each of the heat-treated alloy compositions was measured by using a vibrating-sample magnetometer (VMS) under a magnetic field of 800 kA/m. Coercivity Hc of each alloy composition was measured by using a direct current BH tracer under a magnetic field of 2 kA/m. Magnetic permeability μ was measured by using an impedance analyzer under conditions of 0.4 A/m and 1 kHz. The measurement results are shown in Tables 1 to 14. 
         [0000]    
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Alloy Composition 
                 Phase 
                 T X1   
                 T X2   
                 ΔT 
                 Hc 
                 Bs 
               
               
                   
                 (at %) 
                 (XRD) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (A/m) 
                 (T) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Comparative 
                 Fe 81.7 B 6 Si 9 P 3 Cu 0.3   
                 Amo 
                 443 
                 554 
                 111 
                 7.3 
                 1.54 
               
               
                 Example 1 
               
               
                 Comparative 
                 Fe 82.7 B 7 Si 6 P 4 Cu 0.3   
                 Cry 
                 449 
                 548 
                 99 
                 2.4 
               
               
                 Example 2 
               
               
                 Comparative 
                 Fe 82.7 B 8 Si 5 P 4 Cu 0.3   
                 Amo 
                 486 
                 548 
                 62 
                 2.2 
               
               
                 Example 3 
               
               
                 Comparative 
                 Fe 82.7 B 9 Si 4 P 4 Cu 0.3   
                 Amo 
                 456 
                 531 
                 75 
                 3.2 
               
               
                 Example 4 
               
               
                 Comparative 
                 Fe 82.3 B 12 Si 5 Cu 0.7   
                 Amo 
                 425 
                 525 
                 100 
                 7 
               
               
                 Example 5 
               
               
                 Comparative 
                 Fe 85 B 9 Si 5   
                 Cry 
                 385 
                 551 
                 166 
                 160 
               
               
                 Example 6 
               
               
                 Comparative 
                 Fe 84 B 12 Si 4   
                 Amo 
                 445 
                 540 
                 95 
                 20 
               
               
                 Example 7 
               
               
                 Comparative 
                 Fe 82 B 9 Si 9   
                 Cry 
                 395 
                 547 
                 152 
                 100 
               
               
                 Example 8 
               
               
                   
               
               
                 Amo: Amorphous; Cry: Crystal 
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Alloy Composition 
                 Phase 
                 T X1   
                 T X2   
                 ΔT 
                 Hc 
                 Bs 
               
               
                   
                 (at %) 
                 (XRD) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (A/m) 
                 (T) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Comparative 
                 Fe 78 Si 6.3 B 10 P 5 Cu 0.7   
                 Amo 
                 495 
                 589 
                 94 
                 8.9 
                 1.53 
               
               
                 Example 9 
               
               
                 Example 1 
                 Fe 79 Si 5.3 B 10 P 5 Cu 0.7   
                 Amo 
                 477 
                 578 
                 101 
                 10.1 
                 1.54 
               
               
                 Example 2 
                 Fe 80.3 B 10 Si 5 P 4 Cu 0.7   
                 Amo 
                 454 
                 571 
                 117 
                 13.1 
                 1.58 
               
               
                 Example 3 
                 Fe 81.3 B 7 Si 8 P 3 Cu 0.7   
                 Amo 
                 451 
                 566 
                 115 
                 7.5 
                 1.56 
               
               
                 Example 4 
                 Fe 82.3 B 7 Si 7 P 3 Cu 0.7   
                 Amo 
                 430 
                 555 
                 125 
                 6 
                 1.59 
               
               
                 Example 5 
                 Fe 83.3 B 8 Si 4 P 4 Cu 0.7   
                 Amo 
                 411 
                 547 
                 136 
                 7.2 
                 1.65 
               
               
                 Example 6 
                 Fe 84.3 B 8 Si 4 P 3 Cu 0.7   
                 Amo 
                 396 
                 550 
                 154 
                 8.5 
                 1.64 
               
               
                 Example 7 
                 Fe 85.3 B 10 Si 2 P 2 Cu 0.7   
                 Amo 
                 395 
                 548 
                 153 
                 11 
                 1.58 
               
               
                 Example 8 
                 Fe 85.3 B 8 Si 2 P 4 Cu 0.7   
                 Amo 
                 394 
                 528 
                 134 
                 15 
                 1.57 
               
               
                 Example 9 
                 Fe 85.0 B 10 Si 2 P 2 Cu 1   
                 Amo 
                 389 
                 536 
                 147 
                 3.6 
                 1.56 
               
               
                 Example 10 
                 Fe 86 B 9 Si 2 P 2 Cu 1   
                 Amo 
                 376 
                 529 
                 153 
                 28.8 
                 1.56 
               
             
          
           
               
                 Comparative 
                 Fe 87 B 8 Si 2 P 2 Cu 1   
                 Cry 
                 Continuous strip cannot be obtained. 
               
               
                 Example 10 
               
               
                   
               
               
                 Amo: Amorphous; Cry: Crystal 
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Alloy Composition 
                 Phase 
                 T X1   
                 T X2   
                 ΔT 
                 Hc 
                 Bs 
               
               
                   
                 (at %) 
                 (XRD) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (A/m) 
                 (T) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Comparative 
                 Fe 83.3 B 4 Si 7 P 5 Cu 0.7   
                 Cry 
                 383 
                 549 
                 166 
                 25.2 
                 1.54 
               
               
                 Example 11 
               
               
                 Example 11 
                 Fe 83.3 B 5 Si 6 P 5 Cu 0.7   
                 Amo 
                 422 
                 557 
                 135 
                 13.8 
                 1.56 
               
               
                 Example 12 
                 Fe 83.3 B 6 Si 5 P 5 Cu 0.7   
                 Amo 
                 416 
                 555 
                 139 
                 12.5 
                 1.56 
               
               
                 Example 13 
                 Fe 83.3 B 8 Si 4 P 4 Cu 0.7   
                 Amo 
                 411 
                 547 
                 136 
                 7.2 
                 1.65 
               
               
                 Example 14 
                 Fe 83.3 B 10 Si 3 P 3 Cu 0.7   
                 Amo 
                 419 
                 558 
                 139 
                 10.6 
                 1.57 
               
               
                 Example 15 
                 Fe 85.0 B 10 Si 2 P 2 Cu 1   
                 Amo 
                 389 
                 536 
                 147 
                 3.6 
                 1.56 
               
               
                 Example 16 
                 Fe 83.3 B 12 Si 2 P 2 Cu 0.7   
                 Amo 
                 426 
                 549 
                 123 
                 10.5 
                 1.57 
               
               
                 Example 17 
                 Fe 83.3 B 13 Si 1 P 2 Cu 0.7   
                 Amo 
                 430 
                 539 
                 109 
                 15.1 
                 1.58 
               
               
                 Comparative 
                 Fe 83.3 B 14 Si 1 P 1 Cu 0.7   
                 Cry 
                 425 
                 529 
                 104 
                 13 
                 1.57 
               
               
                 Example 12 
               
               
                   
               
               
                 Amo: Amorphous; Cry: Crystal 
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 Alloy Composition 
                 Phase 
                 T X1   
                 T X2   
                 ΔT 
                 Hc 
                 Bs 
               
               
                   
                 (at %) 
                 (XRD) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (A/m) 
                 (T) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Example 18 
                 Fe 85.3 B 10 Si 0.1 P 3.9 Cu 0.7   
                 Amo 
                 397 
                 528 
                 131 
                 13.4 
                 1.58 
               
               
                 Example 19 
                 Fe 85.3 B 10 Si 0.5 P 3.5 Cu 0.7   
                 Amo 
                 396 
                 535 
                 139 
                 10.7 
                 1.58 
               
               
                 Example 20 
                 Fe 85.3 B 10 Si 1 P 3 Cu 0.7   
                 Amo 
                 397 
                 528 
                 131 
                 12.8 
                 1.57 
               
               
                 Example 21 
                 Fe 85.3 B 10 Si 2 P 2 Cu 0.7   
                 Amo 
                 395 
                 548 
                 153 
                 11 
                 1.59 
               
               
                 Example 22 
                 Fe 83.3 B 8 Si 2 P 6 Cu 0.7   
                 Amo 
                 416 
                 535 
                 119 
                 14.4 
                 1.56 
               
               
                 Example 23 
                 Fe 83.3 B 8 Si 4 P 4 Cu 0.7   
                 Amo 
                 411 
                 547 
                 136 
                 7.2 
                 1.65 
               
               
                 Example 24 
                 Fe 83.3 B 8 Si 6 P 2 Cu 0.7   
                 Amo 
                 420 
                 571 
                 151 
                 16.6 
                 1.56 
               
               
                 Example 25 
                 Fe 81.3 B 7 Si 8 P 3 Cu 0.7   
                 Amo 
                 451 
                 566 
                 115 
                 7.5 
                 1.56 
               
               
                 Comparative 
                 Fe 81.3 B 6 Si 10 P 2 Cu 0.7   
                 Cry 
                 390 
                 574 
                 184 
                 144.5 
                 1.57 
               
               
                 Example 13 
               
               
                   
               
               
                 Amo: Amorphous; Cry: Crystal 
               
             
          
         
       
     
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                 TABLE 5 
               
               
                   
                   
               
               
                   
                 Alloy Composition 
                 Phase 
                 T X1   
                 T X2   
                 ΔT 
                 Hc 
                 Bs 
               
               
                   
                 (at %) 
                 (XRD) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (A/m) 
                 (T) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Comparative 
                 Fe 83.3 B 12 Si 4 Cu 0.7   
                 Amo 
                 423 
                 530 
                 107 
                 7.5 
                 1.58 
               
               
                 Example 14 
               
               
                 Comparative 
                 Fe 82.7 B 12 Si 4 Cu 1.3   
                 Amo 
                 375 
                 520 
                 145 
                 7 
                 1.57 
               
               
                 Example 15 
               
               
                 Comparative 
                 Fe 83.3 B 8 Si 8 P 0 Cu 0.7   
                 Cry 
                 367 
                 554 
                 187 
                 16.3 
                 1.59 
               
               
                 Example 16 
               
               
                 Example 26 
                 Fe 83.3 B 8 Si 7 P 1 Cu 0.7   
                 Amo 
                 420 
                 571 
                 151 
                 16.6 
                 1.56 
               
               
                 Example 27 
                 Fe 83.3 B 8 Si 6 P 2 Cu 0.7   
                 Amo 
                 420 
                 571 
                 151 
                 16.6 
                 1.56 
               
               
                 Example 28 
                 Fe 85.3 B 10 Si 1 P 3 Cu 0.7   
                 Amo 
                 397 
                 528 
                 131 
                 12.8 
                 1.57 
               
               
                 Example 29 
                 Fe 83.3 B 10 Si 3 P 3 Cu 0.7   
                 Amo 
                 419 
                 558 
                 139 
                 10.6 
                 1.57 
               
               
                 Example 30 
                 Fe 83.3 B 8 Si 4 P 4 Cu 0.7   
                 Amo 
                 441 
                 547 
                 136 
                 7.2 
                 1.65 
               
               
                 Example 31 
                 Fe 83.3 B 7 Si 4 P 5 Cu 0.7   
                 Amo 
                 420 
                 550 
                 130 
                 14.8 
                 1.56 
               
               
                 Example 32 
                 Fe 83.3 B 6 Si 4 P 6 Cu 0.7   
                 Amo 
                 416 
                 535 
                 119 
                 14.1 
                 1.56 
               
               
                 Example 33 
                 Fe 82.3 B 7 Si 2 P 8 Cu 0.7   
                 Amo 
                 408 
                 519 
                 111 
                 12 
                 1.56 
               
               
                 Comparative 
                 Fe 81.3 B 6 Si 2 P 10 Cu 0.7   
                 Cry 
                 425 
                 523 
                 98 
                 8 
                 1.51 
               
               
                 Example 17 
               
               
                   
               
               
                 Amo: Amorphous; Cry: Crystal 
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 6 
               
               
                   
                   
               
               
                   
                 Alloy Composition 
                 Phase 
                 T X1   
                 T X2   
                 ΔT 
                 Hc 
                 Bs 
               
               
                   
                 (at %) 
                 (XRD) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (A/m) 
                 (T) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Example 34 
                 Fe 83.3 B 8 Si 4 P 4 Cu 0.7   
                 Amo 
                 411 
                 547 
                 136 
                 7.2 
                 1.65 
               
               
                 Example 35 
                 Fe 83.3 B 8 Si 4 P 3 C 1 Cu 0.7   
                 Amo 
                 408 
                 552 
                 144 
                 6 
                 1.59 
               
               
                 Example 36 
                 Fe 83.3 B 7 Si 4 P 4 C 1 Cu 0.7   
                 Amo 
                 402 
                 546 
                 144 
                 8 
                 1.56 
               
               
                 Example 37 
                 Fe 83.3 B 7 Si 4 P 3 C 2 Cu 0.7   
                 Amo 
                 413 
                 554 
                 141 
                 6 
                 1.58 
               
               
                 Example 38 
                 Fe 83.3 B 7 Si 3 P 2 C 4 Cu 0.7   
                 Amo 
                 404 
                 561 
                 157 
                 23.7 
                 1.58 
               
               
                 Example 39 
                 Fe 83.3 B 7 Si 2 P 2 C 5 Cu 0.7   
                 Amo 
                 404 
                 553 
                 149 
                 14.6 
                 1.62 
               
               
                 Comparative 
                 Fe 83.3 B 6 Si 2 P 2 C 6 Cu 0.7   
                 Cry 
                 406 
                 556 
                 150 
                 10.4 
                 1.59 
               
               
                 Example 18 
               
               
                   
               
               
                 Amo: Amorphous; Cry: Crystal 
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 7 
               
               
                   
                   
               
               
                   
                 Alloy Composition 
                 Phase 
                 T X1   
                 T X2   
                 ΔT 
                 Hc 
                 Bs 
               
               
                   
                 (at %) 
                 (XRD) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (A/m) 
                 (T) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Comparative 
                 Fe 84 B 8 Si 4 P 4   
                 Amo 
                 445 
                 539 
                 94 
                 12 
                 1.61 
               
               
                 Example 19 
               
               
                 Comparative 
                 Fe 83.7 B 8 Si 4 P 4 Cu 0.3   
                 Amo 
                 439 
                 551 
                 112 
                 5.5 
                 1.57 
               
               
                 Example 20 
               
               
                 Example 40 
                 Fe 83.6 B 8 Si 4 P 4 Cu 0.4   
                 Amo 
                 427 
                 552 
                 125 
                 6 
                 1.56 
               
               
                 Example 41 
                 Fe 83.5 B 8 Si 4 P 4 Cu 0.5   
                 Amo 
                 425 
                 556 
                 131 
                 6.3 
                 1.57 
               
               
                 Example 42 
                 Fe 83.3 B 8 Si 4 P 4 Cu 0.7   
                 Amo 
                 411 
                 547 
                 136 
                 7.2 
                 1.65 
               
               
                 Example 43 
                 Fe 83.0 B 8 Si 4 P 4 Cu 1.0   
                 Amo 
                 441 
                 552 
                 111 
                 5.7 
                 1.59 
               
               
                 Example 44 
                 Fe 85.0 B 8 Si 2 P 4 Cu 1.0   
                 Amo 
                 389 
                 537 
                 148 
                 9 
                 1.61 
               
               
                 Example 45 
                 Fe 82.7 B 8 Si 4 P 4 Cu 1.3   
                 Amo 
                 387 
                 537 
                 150 
                 7.5 
                 1.58 
               
               
                 Example 46 
                 Fe 82.6 B 8 Si 4 P 4 Cu 1.4   
                 Amo 
                 408 
                 556 
                 148 
                 40 
                 1.57 
               
               
                 Comparative 
                 Fe 82.5 B 8 Si 4 P 4 Cu 1.5   
                 Cry 
                 388 
                 551 
                 163 
                 5.8 
                 1.56 
               
               
                 Example 21 
               
               
                 Comparative 
                 Fe 84.5 B 10 Si 2 P 2 Cu 1.5   
                 Cry 
                 358 
                 534 
                 176 
                 110 
                 1.57 
               
               
                 Example 22 
               
               
                   
               
               
                 Amo: Amorphous; Cry: Crystal 
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 8 
               
               
                   
                   
               
               
                   
                 Magnetic 
                   
                   
                 Average 
                 Heat 
               
               
                   
                 Permeability 
                 Hc (A/m) 
                 Bs (T) 
                 Diameter (nm) 
                 Treatment Condition 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Comparative 
                   
                 170 
                   
                 x 
                 460° C. × 10 Minutes 
               
               
                 Example 1 
               
               
                 Comparative 
                   
                 115 
                   
                 x 
                 490° C. × 10 Minutes 
               
               
                 Example 2 
               
               
                 Comparative 
                   
                 220 
                   
                 x 
                 475° C. × 10 Minutes 
               
               
                 Example 3 
               
               
                 Comparative 
                   
                 320 
                   
                 x 
                 460° C. × 10 Minutes 
               
               
                 Example 4 
               
               
                 Comparative 
                 7000 
                 100 
                 1.80 
                 x 
                 450° C. × 10 Minutes 
               
               
                 Example 5 
               
               
                 Comparative 
                 600 
                 220 
                 1.67 
                 x 
                 430° C. × 10 Minutes 
               
               
                 Example 6 
               
               
                 Comparative 
                 2000 
                 570 
                 1.83 
                 x 
                 450° C. × 10 Minutes 
               
               
                 Example 7 
               
               
                 Comparative 
                 1000 
                 150 
                 1.67 
                 x 
                 450° C. × 10 Minutes 
               
               
                 Example 8 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
               
               
             
           
               
                   
                 TABLE 9 
               
               
                   
                   
               
               
                   
                 Magnetic 
                   
                   
                 Average 
                 Heat 
               
               
                   
                 Permeability 
                 Hc (A/m) 
                 Bs (T) 
                 Diameter (nm) 
                 Treatment Condition 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Comparative 
                 11000 
                 8.2 
                 1.63 
                 19 
                 475° C. × 10 Minutes 
               
               
                 Example 9 
               
               
                 Example 1 
                 14000 
                 4.5 
                 1.67 
                 21 
                 475° C. × 10 Minutes 
               
               
                 Example 2 
                 18000 
                 3.3 
                 1.69 
                 18 
                 475° C. × 10 Minutes 
               
               
                 Example 3 
                 21000 
                 12 
                 1.77 
                 20 
                 480° C. × 10 Minutes 
               
               
                 Example 4 
                 19000 
                 10 
                 1.79 
                 22 
                 480° C. × 10 Minutes 
               
               
                 Example 5 
                 30000 
                 7 
                 1.88 
                 15 
                 475° C. × 10 Minutes 
               
               
                 Example 6 
                 20000 
                 10 
                 1.94 
                 17 
                 450° C. × 30 Minutes 
               
               
                 Example 7 
                 16000 
                 16 
                 1.97 
                 21 
                 430° C. × 10 Minutes 
               
               
                 Example 8 
                 11000 
                 20 
                 2.01 
                 24 
                 430° C. × 10 Minutes 
               
               
                 Example 9 
                 22000 
                 9 
                 1.82 
                 18 
                 460° C. × 10 Minutes 
               
               
                 Example 10 
                 11000 
                 15.3 
                 1.92 
                 20 
                 460° C. × 10 Minutes 
               
             
          
           
               
                 Comparative 
                 Continuous strip cannot be obtained. 
               
               
                 Example 10 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 10 
               
               
                   
                   
               
               
                   
                 Magnetic 
                   
                   
                 Average 
                 Heat 
               
               
                   
                 Permeability 
                 Hc (A/m) 
                 Bs (T) 
                 Diameter (nm) 
                 Treatment Condition 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Comparative 
                 700 
                 129 
                 1.70 
                 x 
                 475° C. × 10 Minutes 
               
               
                 Example 11 
               
               
                 Example 11 
                 12000 
                 18 
                 1.77 
                 24 
                 475° C. × 10 Minutes 
               
               
                 Example 12 
                 24000 
                 5 
                 1.79 
                 21 
                 450° C. × 10 Minutes 
               
               
                 Example 13 
                 30000 
                 7 
                 1.88 
                 15 
                 475° C. × 10 Minutes 
               
               
                 Example 14 
                 20000 
                 5.4 
                 1.82 
                 14 
                 475° C. × 10 Minutes 
               
               
                 Example 15 
                 22000 
                 9 
                 1.90 
                 18 
                 460° C. × 10 Minutes 
               
               
                 Example 16 
                 18000 
                 8.2 
                 1.83 
                 17 
                 450° C. × 10 Minutes 
               
               
                 Example 17 
                 14000 
                 13.9 
                 1.85 
                 16 
                 475° C. × 10 Minutes 
               
               
                 Comparative 
                 7000 
                 24 
                 1.86 
                 18 
                 460° C. × 10 Minutes 
               
               
                 Example 12 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 11 
               
               
                   
                   
               
               
                   
                 Magnetic 
                   
                   
                 Average 
                 Heat 
               
               
                   
                 Permeability 
                 Hc (A/m) 
                 Bs (T) 
                 Diameter (nm) 
                 Treatment Condition 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Example 18 
                 11000 
                 14 
                 1.89 
                 16 
                 450° C. × 10 Minutes 
               
               
                 Example 19 
                 13000 
                 9.5 
                 1.90 
                 17 
                 450° C. × 10 Minutes 
               
               
                 Example 20 
                 23000 
                 6.8 
                 1.92 
                 14 
                 450° C. × 10 Minutes 
               
               
                 Example 21 
                 16000 
                 16 
                 1.97 
                 21 
                 430° C. × 10 Minutes 
               
               
                 Example 22 
                 19000 
                 4.1 
                 1.78 
                 16 
                 450° C. × 10 Minutes 
               
               
                 Example 23 
                 30000 
                 1 
                 1.88 
                 15 
                 475° C. × 10 Minutes 
               
               
                 Example 24 
                 18000 
                 10.7 
                 1.84 
                 19 
                 475° C. × 10 Minutes 
               
               
                 Example 25 
                 21000 
                 12 
                 1.73 
                 20 
                 475° C. × 10 Minutes 
               
               
                 Comparative 
                 7700 
                 31 
                 1.73 
                 x 
                 475° C. × 10 Minutes 
               
               
                 Example 13 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 12 
               
               
                   
                   
               
               
                   
                 Magnetic 
                   
                   
                 Average 
                 Heat 
               
               
                   
                 Permeability 
                 Hc (A/m) 
                 Bs (T) 
                 Diameter (nm) 
                 Treatment Condition 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Comparative 
                 400 
                 670 
                 1.85 
                 x 
                 475° C. × 10 Minutes 
               
               
                 Example 14 
               
               
                 Comparative 
                 9000 
                 68 
                 1.7 
                 x 
                 450° C. × 10 Minutes 
               
               
                 Example 15 
               
               
                 Comparative 
                 1700 
                 68 
                 1.79 
                 x 
                 450° C. × 10 Minutes 
               
               
                 Example 16 
               
               
                 Example 26 
                 12000 
                 14 
                 1.81 
                 19 
                 450° C. × 10 Minutes 
               
               
                 Example 27 
                 19000 
                 10.7 
                 1.80 
                 16 
                 450° C. × 10 Minutes 
               
               
                 Example 28 
                 23000 
                 6.8 
                 1.92 
                 14 
                 450° C. × 10 Minutes 
               
               
                 Example 29 
                 26000 
                 5.4 
                 1.84 
                 13 
                 450° C. × 10 Minutes 
               
               
                 Example 30 
                 30000 
                 7 
                 1.88 
                 15 
                 475° C. × 10 Minutes 
               
               
                 Example 31 
                 22000 
                 4.6 
                 1.74 
                 16 
                 450° C. × 10 Minutes 
               
               
                 Example 32 
                 14000 
                 4.1 
                 1.69 
                 17 
                 450° C. × 10 Minutes 
               
               
                 Example 33 
                 17000 
                 4.5 
                 1.69 
                 16 
                 450° C. × 10 Minutes 
               
               
                 Comparative 
                 1700 
                 68 
                 1.65 
                 x 
                 450° C. × 10 Minutes 
               
               
                 Example 17 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 13 
               
               
                   
                   
               
               
                   
                 Magnetic 
                   
                   
                 Average 
                 Heat 
               
               
                   
                 Permeability 
                 Hc (A/m) 
                 Bs (T) 
                 Diameter (nm) 
                 Treatment Condition 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Example 34 
                 30000 
                 7 
                 1.88 
                 15 
                 475° C. × 10 Minutes 
               
               
                 Example 35 
                 21000 
                 7 
                 1.87 
                 20 
                 460° C. × 30 Minutes 
               
               
                 Example 36 
                 22000 
                 7 
                 1.87 
                 20 
                 460° C. × 30 Minutes 
               
               
                 Example 37 
                 26000 
                 8 
                 1.87 
                 16 
                 460° C. × 30 Minutes 
               
               
                 Example 38 
                 11000 
                 19 
                 1.85 
                 20 
                 450° C. × 30 Minutes 
               
               
                 Example 39 
                 13000 
                 16.3 
                 1.82 
                 22 
                 450° C. × 30 Minutes 
               
               
                 Comparative 
                 3900 
                 28.8 
                 1.83 
                 x 
                 450° C. × 30 Minutes 
               
               
                 Example 18 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 14 
               
               
                   
                   
               
               
                   
                 Magnetic 
                   
                   
                 Average 
                 Heat 
               
               
                   
                 Permeability 
                 Hc (A/m) 
                 Bs (T) 
                 Diameter (nm) 
                 Treatment Condition 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Comparative 
                 2000 
                 300 
                 1.70 
                 x 
                 475° C. × 10 Minutes 
               
               
                 Example 19 
               
               
                 Comparative 
                 900 
                 80 
                 1.79 
                 x 
                 490° C. × 10 Minutes 
               
               
                 Example 20 
               
               
                 Example 40 
                 16000 
                 10 
                 1.84 
                 23 
                 470° C. × 10 Minutes 
               
               
                 Example 41 
                 19000 
                 9.5 
                 1.83 
                 21 
                 470° C. × 10 Minutes 
               
               
                 Example 42 
                 30000 
                 7 
                 1.88 
                 15 
                 475° C. × 10 Minutes 
               
               
                 Example 43 
                 21000 
                 8.2 
                 1.86 
                 19 
                 450° C. × 10 Minutes 
               
               
                 Example 44 
                 25000 
                 6 
                 1.85 
                 16 
                 450° C. × 10 Minutes 
               
               
                 Example 45 
                 18000 
                 6 
                 1.81 
                 22 
                 475° C. × 10 Minutes 
               
               
                 Example 46 
                 23000 
                 7.2 
                 1.77 
                 12 
                 475° C. × 10 Minutes 
               
               
                 Comparative 
                 3200 
                 54 
                 1.68 
                 x 
                 475° C. × 10 Minutes 
               
               
                 Example 21 
               
               
                 Comparative 
                 4100 
                 33 
                 1.85 
                 x 
                 450° C. × 10 Minutes 
               
               
                 Example 22 
               
               
                   
               
             
          
         
       
     
         [0033]    As understood from Tables 1 to 7, each of the alloy compositions of Examples 1-46 has an amorphous phase as a main phase after the rapid cooling process. 
         [0034]    As understood from Tables 8 to 14, each of the heat-treated alloy composition of Examples 1-46 is nano-crystallized so that the bccFe phase included therein has an average diameter of 25 nm or smaller. On the other hand, each of the heat-treated alloy composition of Comparative Examples 1-22 has various particle sizes or heterogeneous particle sizes or is not nano-crystallized (In columns “Average Diameter” of Tables 8 to 14, “x” shows a not-nano-crystallized alloy. Similar results are understood from  FIG. 1 . Graphs of Comparative Examples 7, 14 and 15 show that their coercivity Hc become larger at increasing process temperatures. On the other hand, graphs of Examples 5 and 6 include curves in which their coercivity Hc are reduced at increasing process temperatures. The reduced coercivity Hc is caused by nano-crystallization. 
         [0035]    With reference to  FIG. 2 , the pre-heat-treatment alloy composition of Comparative Example 7 has initial microcrystals which have diameters larger than 10 nm so that the strip of the alloy composition cannot be flat on itself but is broken upon the 180 degree bend test. With reference to  FIG. 3 , the pre-heat-treatment alloy composition of Example 5 has initial microcrystals which have diameters of 10 nm or smaller so that the strip of alloy composition can be flat on itself upon the 180 degree bend test. In addition,  FIG. 3  shows that the post-heat-treatment alloy composition, i.e. the Fe-based nano-crystalline alloy of Example 5 has homogeneous Fe-based nanocrystals, which have an average diameter of 15 nm smaller than 25 nm and provide a superior coercivity Hc property of  FIG. 1 . The other Examples 1-4, 6-46 are similar to Example 5. Each of the pre-heat-treatment alloy compositions thereof has initial microcrystals existing in an amorphous phase which have diameters of 10 nm or smaller. Each of the post-heat-treatment alloy compositions (the Fe-based nano-crystalline alloys) thereof has homogeneous Fe-based nanocrystals, which have an average diameter of 15 nm smaller than 25 nm. Therefore, each of the post-heat-treatment alloy compositions (the Fe-based nano-crystalline alloys) of Examples 1-46 can have a superior coercivity Hc property. 
         [0036]    As understood from Tables 1 to 7, each of the alloy compositions of Examples 1-46 has a crystallization start temperature difference ΔT (=T x2 −T x1 ) of 100° C. or more. The alloy composition is exposed to a heat treatment under the condition that its maximum instantaneous heat treatment temperature is in a range between its first crystallization start temperature T x1  and its second crystallization start temperature T x2 , so that superior soft magnetic properties (coercivity Hc, magnetic permeability μ) can be obtained as shown in Tables 1 to 14.  FIG. 4  also shows that each of the alloy compositions of Examples 5, 6, 20 and 44 has its crystallization start temperature difference ΔT of 100° C. or more. On the other hand, DSC curves of  FIG. 4  show that the alloy compositions of Comparative Examples 7 and 19 have narrow crystallization start temperature differences ΔT, respectively. Because of the narrow crystallization start temperature differences ΔT, the post-heat-treatment alloy compositions of Comparative Examples 7 and 19 have inferior soft magnetic properties. In  FIG. 4 , the alloy composition of Comparative Example 22 appears to have a broad crystallization start temperature difference ΔT. However, the broad crystallization start temperature difference ΔT is caused by the fact that its main phase is a crystal phase as shown in Table 7. Therefore, the post-heat-treatment alloy composition of Comparative Example 22 has inferior soft magnetic properties. 
         [0037]    The alloy compositions of Examples 1-10 and Comparative Examples 9 and 10 listed in Tables 8 and 9 correspond to the cases where the Fe content is varied from 79 atomic % to 87 atomic %. Each of the alloy compositions of Examples 1-10 listed in Table 9 has magnetic permeability μ of 10,000 or more, saturation magnetic flux density Bs of 1.65 T or more and coercivity Hc of 20 A/m or less. Therefore, a range of from 79 atomic % to 86 atomic % defines a condition range for the Fe content. If the Fe content is 81 atomic % or more, the saturation magnetic flux density Bs of 1.7 T or more can be obtained. Therefore, it is preferable that the Fe content is 81 atomic % or more in a field, such as a transformer or a motor, where high saturation magnetic flux density Bs is required. On the other hand, the Fe content of Comparative Example 9 is 78 atomic %. The alloy composition of Comparative Example 9 has an amorphous phase as its main phase as shown in Table 2. However, the post-heat-treatment crystalline particles are rough as shown in Table 9 so that its magnetic permeability μ and its coercivity Hc are out of the above-mentioned property range of Examples 1-10. The Fe content of Comparative Example 10 is 87 atomic %. The alloy composition of Comparative Example 10 cannot form a continuous strip. In addition, the alloy composition of Comparative Example 10 has a crystalline phase as its main phase. 
         [0038]    The alloy compositions of Examples 11-17 and Comparative Examples 11 and 12 listed in Table 10 correspond to the cases where the B content is varied from 4 atomic % to 14 atomic %. Each of the alloy compositions of Examples 11-17 listed in Table 10 has magnetic permeability μ of 10,000 or more, saturation magnetic flux density Bs of 1.65 T or more and coercivity Hc of 20 A/m or less. Therefore, a range of from 5 atomic % to 13 atomic % defines a condition range for the B content. In particular, it is preferable that the B content is 10 atomic % or less so that the alloy composition has a broad crystallization start temperature difference ΔT of 120° C. or more and a temperature at which the alloy composition finishes to be melt becomes lower than that of Fe amorphous alloy. The B content of Comparative Example 11 is 4 atomic %, and the B content of Comparative Example 12 is 14 atomic %. The alloy compositions of Comparative Examples 11, 12 have rough crystalline particles posterior to the heat treatment, as shown in Table 10, so that their magnetic permeability μ and their coercivity Hc are out of the above-mentioned property range of Examples 11-17. 
         [0039]    The alloy compositions of Examples 18-25 and Comparative Example 13 listed in Table 11 correspond to the cases where the Si content is varied from 0.1 atomic % to 10 atomic %. Each of the alloy compositions of Examples 18-25 listed in Table 11 has magnetic permeability μ of 10,000 or more, saturation magnetic flux density Bs of 1.65 T or more and coercivity He of 20 A/m or less. Therefore, a range of from 0 atomic % to 8 atomic % (excluding zero atomic %) defines a condition range for the Si content. The B content of Comparative Example 13 is 10 atomic %. The alloy composition of Comparative Example 13 has low saturation magnetic flux density Bs and rough crystalline particles posterior to the heat treatment so that their magnetic permeability μ and their coercivity Hc are out of the above-mentioned property range of Examples 18-25. 
         [0040]    The alloy compositions of Examples 26-33 and Comparative Examples 14-17 listed in Table 12 correspond to the cases where the P content is varied from 0 atomic % to 10 atomic %. Each of the alloy compositions of Examples 26-33 listed in Table 12 has magnetic permeability μ of 10,000 or more, saturation magnetic flux density Bs of 1.65 T or more and coercivity Hc of 20 A/m or less. Therefore, a range of from 1 atomic % to 8 atomic % defines a condition range for the P content. In particular, it is preferable that the P content is 5 atomic % or less so that the alloy composition has a broad crystallization start temperature difference ΔT of 120° C. or more and has saturation magnetic flux density Bs larger than 1.7 T. The P contents of Comparative Examples 14-16 are each 0 atomic %. The alloy compositions of Comparative Examples 14-16 have rough crystalline particles posterior to the heat treatment so that their magnetic permeability μ and their coercivity Hc are out of the above-mentioned property range of Examples 26-33. The P content of Comparative Example 17 is 10 atomic %. The alloy composition of Comparative Example 17 also has rough crystalline particles posterior to the heat treatment so that its magnetic permeability μ and its coercivity Hc are out of the above-mentioned property range of Examples 26-33. 
         [0041]    The alloy compositions of Examples 34-39 and Comparative Example 18 listed in Table 13 correspond to the cases where the C content is varied from 0 atomic % to 6 atomic %. Each of the alloy compositions of Examples 34-39 listed in Table 13 has magnetic permeability μ of 10,000 or more, saturation magnetic flux density Bs of 1.65 T or more and coercivity Hc of 20 A/m or less. Therefore, a range of from 0 atomic % to 5 atomic % defines a condition range for the C content. Note here that, if the C content is 4 atomic % or more, its continuous strip has a thickness thicker than 30 μm, as Example 38 or 39, so that it is difficult to be flat on itself upon the 180 degree bend test. Therefore, it is preferable that the C content is 3 atomic % or less. The C content of Comparative Example 18 is 6 atomic %. The alloy composition of Comparative Example 18 has rough crystalline particles posterior to the heat treatment so that its magnetic permeability μ and its coercivity Hc are out of the above-mentioned property range of Examples 34-39. 
         [0042]    The alloy compositions of Examples 40-46 and Comparative Examples 19-22 listed in Table 14 correspond to the cases where the Cu content is varied from 0 atomic % to 1.5 atomic %. Each of the alloy compositions of Examples 40-46 listed in Table 14 has magnetic permeability μ of 10,000 or more, saturation magnetic flux density Bs of 1.65 T or more and coercivity Hc of 20 A/m or less. Therefore, a range of from 0.4 atomic % to 1.4 atomic % defines a condition range for the Cu content. The Cu content of Comparative Example 19 is 0 atomic %, and the Cu content of Comparative Example 20 is 0.3 atomic %. The alloy compositions of Comparative Examples 19 and 20 have rough crystalline particles posterior to the heat treatment so that their magnetic permeability μ and their coercivity Hc are out of the above-mentioned property range of Examples 40-46. The Cu contents of Comparative Examples 21 and 22 are each 1.5 atomic %. The alloy compositions of Comparative Examples 21 and 22 also have rough crystalline particles posterior to the heat treatment so that their magnetic permeability μ and their coercivity Hc are out of the above-mentioned property range of Examples 40-46. In addition, the alloy compositions of Comparative Examples 21 and 22 each has, as its main phase, not an amorphous phase but a crystalline phase. 
         [0043]    As for each of the Fe-based nano-crystalline alloys obtained by exposing the alloy compositions of Examples 1, 2, 5, 6 and 44, their saturation magnetostriction was measured by the strain gage method. As the result, the Fe-based nano-crystalline alloys of Examples 1, 2, 5, 6 and 44 had saturation magnetostriction of 8.2×10 −6 , 5.3×10 −5 , 3.8×10 −6 , 3.1×10 −6  and 2.3×10 −6 , respectively. On the other hand, the saturation magnetostriction of Fe amorphous is 27×10 −6 , and the Fe-based nano-crystalline alloy of JP-A 2007-270271 (Patent Document 1) has saturation magnetostriction of 14×10 −6 . In comparison therewith, the Fe-based nano-crystalline alloys of Examples 1, 2, 5, 6 and 44 have very smaller so as to have high magnetic permeability, low coercivity and low core loss. In other words, the reduced saturation magnetostriction contributes to improvement of soft magnetic properties and suppression of noise or vibration. Therefore, it is desirable that saturation magnetostriction is 10×10 −6  or less. In particular, in order to obtain magnetic permeability of 20,000 or more, it is preferable that saturation magnetostriction is 5×10 −6  or less. 
       Examples 47-55 and Comparative Examples 23-25 
       [0044]    Materials were respectively weighed so as to provide alloy compositions of Examples 47-55 of the present invention and Comparative Examples 23-25 as listed in Table 15 below and were melted by the high-frequency induction melting process. The melted alloy compositions were processed by the single-roll liquid quenching method under the atmosphere so as to produce continuous strips which have thicknesses of about 20 μm and about 30 μm, a width of about 15 mm and a length of about 10 m. For each of the continuous strip of the alloy compositions, phase identification was carried out through the X-ray diffraction method. Toughness of each continuous strip was evaluated by the 180 degree bend test. For each continuous strip having the thickness of about 20 μm, the first crystallization start temperature and the second crystallization start temperature were evaluated by using a differential scanning calorimetory (DSC). In addition, for Examples 47-55 and Comparative Examples 23-25, the alloy compositions of about 20 μm thickness were exposed to heat treatment processes which were carried out under the heat treatment conditions listed in Table 16. Saturation magnetic flux density Bs of each of the heat-treated alloy compositions was measured by using a vibrating-sample magnetometer (VMS) under a magnetic field of 800 kA/m. Coercivity Hc of each alloy composition was measured by using a direct current BH tracer under a magnetic field of 2 kA/m. The measurement results are shown in Tables 15 and 16. 
         [0000]    
       
         
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 15 
               
               
                   
                   
               
               
                   
                 Alloy Composition 
                   
                 Thickness 
                 Phase 
                 Bent 
                 T X1   
                 T X2   
                 ΔT 
                 Hc 
                 Bs 
               
               
                   
                 (at %) 
                 z/x 
                 (μm) 
                 (XRD) 
                 Test 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (A/m) 
                 (T) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Comparative 
                 Fe 83.7 B 8 Si 4 P 4 Cu 0.3   
                 0.06 
                 22 
                 Amo 
                 ∘ 
                 436 
                 552 
                 116 
                  9.4 
                 1.56 
               
               
                 Example 23 
                   
                   
                 29 
                 Amo 
                 ∘ 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 Example 47 
                 Fe 83.6 B 8 Si 4 P 4 Cu 0.4   
                 0.08 
                 19 
                 Amo 
                 ∘ 
                 426 
                 558 
                 132 
                 10.1 
                 1.56 
               
               
                   
                   
                   
                 31 
                 Amo 
                 ∘ 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 Example 48 
                 Fe 83.3 B 8 Si 4 P 4 Cu 0.7   
                 0.175 
                 20 
                 Amo 
                 ∘ 
                 413 
                 557 
                 144 
                  8.2 
                 1.60 
               
               
                   
                   
                   
                 32 
                 Amo 
                 ∘ 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 Example 49 
                 Fe 84.9 B 10 Si 0.1 P 3.9 Cu 1.1   
                 0.26 
                 19 
                 Amo 
                 ∘ 
                 395 
                 529 
                 134 
                 11.3 
                 1.58 
               
               
                   
                   
                   
                 28 
                 Cry 
                 x 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 Example 50 
                 Fe 84.9 B 10 Si 0.5 P 3.5 Cu 1.1   
                 0.34 
                 18 
                 Amo 
                 ∘ 
                 396 
                 535 
                 139 
                 11.2 
                 1.57 
               
               
                   
                   
                   
                 29 
                 Cry 
                 x 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 Example 51 
                 Fe 84.9 B 10 Si 1 P 3 Cu 1.1   
                 0.4 
                 21 
                 Amo 
                 ∘ 
                 374 
                 543 
                 169 
                 14     
                 1.58 
               
               
                   
                   
                   
                 27 
                 Cry 
                 x 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 Example 52 
                 Fe 84.9 B 10 Si 2 P 2 Cu 1.1   
                 0.55 
                 18 
                 Amo 
                 ∘ 
                 394 
                 548 
                 154 
                  9.5 
                 1.56 
               
               
                   
                   
                   
                 26 
                 Amo 
                 ∘ 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 Example 53 
                 Fe 84.8 B 10 Si 2 P 2 Cu 1.2   
                 0.6 
                 22 
                 Amo 
                 ∘ 
                 398 
                 549 
                 151 
                 17     
                 1.56 
               
               
                   
                   
                   
                 28 
                 Amo 
                 Δ 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 Example 54 
                 Fe 84.8 B 10 Si 2.5 P 1.5 Cu 1.2   
                 0.8 
                 21 
                 Amo 
                 ∘ 
                 388 
                 546 
                 158 
                 18.2 
                 1.56 
               
               
                   
                   
                   
                 26 
                 Amo 
                 Δ 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 Example 55 
                 Fe 85.3 B 10 Si 3 P 1 Cu 0.7   
                 0.7 
                 19 
                 Amo 
                 ∘ 
                 395 
                 548 
                 153 
                 15.4 
                 1.55 
               
               
                   
                   
                   
                 29 
                 Cry 
                 x 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 Comparative 
                 Fe 84.8 B 10 Si 3 P 1 Cu 1.2   
                 1.2 
                 21 
                 Amo 
                 x 
                 394 
                 539 
                 145 
                 35.5 
                 1.57 
               
               
                 Example 24 
                   
                   
                 27 
                 Cry 
                 x 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 Comparative 
                 Fe 84.8 B 10 Si 4 Cu 1.2   
                   
                 20 
                 Cry 
                 x 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 Example 25 
                   
                   
                 26 
                 Cry 
                 x 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
               
               
                 Amo: Amorphous; Cry: Crystal 
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 16 
               
               
                   
                   
               
               
                   
                 Magnetic 
                   
                   
                 Average 
                 Heat 
               
               
                   
                 Permeability 
                 Hc (A/m) 
                 Bs (T) 
                 Diameter (nm) 
                 Treatment Condition 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Comparative 
                 1200 
                 130 
                 1.78 
                 x 
                 475° C. × 10 Minutes 
               
               
                 Example 23 
               
               
                 Example 47 
                 12000 
                 18 
                 1.84 
                 18 
                 475° C. × 10 Minutes 
               
               
                 Example 48 
                 25000 
                 6.4 
                 1.83 
                 15 
                 475° C. × 10 Minutes 
               
               
                 Example 49 
                 23000 
                 14.6 
                 1.88 
                 16 
                 450° C. × 10 Minutes 
               
               
                 Example 50 
                 14000 
                 9.5 
                 1.87 
                 16 
                 450° C. × 10 Minutes 
               
               
                 Example 51 
                 27000 
                 9 
                 1.88 
                 12 
                 450° C. × 10 Minutes 
               
               
                 Example 52 
                 14000 
                 16.9 
                 1.91 
                 15 
                 450° C. × 10 Minutes 
               
               
                 Example 53 
                 21000 
                 8 
                 1.90 
                 10 
                 450° C. × 10 Minutes 
               
               
                 Example 54 
                 20000 
                 14 
                 1.90 
                 15 
                 450° C. × 10 Minutes 
               
               
                 Example 55 
                 16000 
                 18 
                 1.92 
                 15 
                 450° C. × 10 Minutes 
               
               
                 Comparative 
                 4500 
                 36 
                 1.89 
                 x 
                 450° C. × 10 Minutes 
               
               
                 Example 24 
               
               
                 Comparative 
                 x 
                 x 
                 x 
                 x 
                 450° C. × 10 Minutes 
               
               
                 Example 25 
               
               
                   
               
             
          
         
       
     
         [0045]    As understood from Table 15, each of the continuous strips of about 20 μm thickness formed of the alloy compositions of Examples 47-55 has an amorphous phase as a main phase after the rapid cooling process and is capable of being flat on itself upon the 180 degree bend test. 
         [0046]    The alloy compositions of Examples 47-55 and Comparative Examples 23, 24 listed in Table 16 correspond to the cases where the specific ratio z/x is varied from 0.06 to 1.2. Each of the alloy compositions of Examples 47-55 listed in Table 16 has magnetic permeability μ of 10,000 or more, saturation magnetic flux density Bs of 1.65 T or more and coercivity He of 20 A/m or less. Therefore, a range of from 0.08 to 0.8 defines a condition range for the specific ratio z/x. As understood from Examples 52-54, if the specific ratio z/x is larger than 0.55, the strip of about 30 μm thickness becomes brittle so as to be partially broken (Δ) or completely broken (x) upon the 180 degree bend test. Therefore, it is preferable that the specific ratio z/x is 0.55 or less. Likewise, because the strip becomes brittle if the Cu content is larger than 1.1 atomic %, it is preferable that the Cu content is 1.1 atomic % or less. 
         [0047]    The alloy compositions of Examples 47-55 and Comparative Example 23 listed in Table 16 correspond to the cases where the Si content is varied from 0 to 4 atomic %. Each of the alloy compositions of Examples 47-55 listed in Table 16 has magnetic permeability μ of 10,000 or more, saturation magnetic flux density Bs of 1.65 T or more and coercivity Hc of 20 A/m or less. Therefore, it is understood that a range larger than 0 atomic % defines a condition range for the Si content, as mentioned above. As understood from Examples 49-53, if the Si content is less than 2 atomic %, the alloy composition becomes crystallized and becomes brittle so that it is difficult to form a thicker continuous strip. Therefore, in consideration of toughness, it is preferable that the Si content is 2 atomic % or more. 
         [0048]    The alloy compositions of Examples 47-55 and Comparative Examples 23-25 listed in Table 16 correspond to the cases where the P content is varied from 0 to 4 atomic %. Each of the alloy compositions of Examples 47-55 listed in Table 16 has magnetic permeability μ of 10,000 or more, saturation magnetic flux density Bs of 1.65 T or more and coercivity Hc of 20 A/m or less. Therefore, it is understood that a range larger than 1 atomic % defines a condition range for the P content, as mentioned above. As understood from Examples 52-55, if the P content is less than 2 atomic %, the alloy composition becomes crystallized and becomes brittle so that it is difficult to form a thicker continuous strip. Therefore, in consideration of toughness, it is preferable that the P content is 2 atomic % or more. 
       Examples 56-64 and Comparative Example 26 
       [0049]    Materials were respectively weighed so as to provide alloy compositions of Examples 56-64 of the present invention and Comparative Example 26 as listed in Tables 17 below and were arc melted. The melted alloy compositions were processed by the single-roll liquid quenching method under the atmosphere so as to produce continuous strips which have various thicknesses, a width of about 3 mm and a length of about 5 to 15 m. For each of the continuous strip of the alloy compositions, phase identification was carried out through the X-ray diffraction method. Their first crystallization start temperatures and their second crystallization start temperatures were evaluated by using a differential scanning calorimetory (DSC). In addition, the alloy compositions of Examples 56-64 and Comparative Example 26 were exposed to heat treatment processes which were carried out under the heat treatment conditions listed in Table 18. Saturation magnetic flux density Bs of each of the heat-treated alloy compositions was measured by using a vibrating-sample magnetometer (VMS) under a magnetic field of 800 kA/m. Coercivity Hc of each alloy composition was measured by using a direct current BH tracer under a magnetic field of 2 kA/m. Magnetic permeability μ was measured by using an impedance analyzer under conditions of 0.4 A/m and 1 kHz. The measurement results are shown in Tables 17 and 18. 
         [0000]    
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 17 
               
               
                   
                   
               
               
                   
                 Alloy Composition 
                 Phase 
                 T X1   
                 T X2   
                 ΔT 
                 Hc 
                 Bs 
               
               
                   
                 (at %) 
                 (XRD) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (A/m) 
                 (T) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Example 56 
                 Fe 83.3 B 8 Si 4 P 4 Cu 0.7   
                 Amo 
                 411 
                 547 
                 136 
                 7.2 
                 1.65 
               
               
                 Example 57 
                 Fe 82.8 B 8 Si 4 P 4 Cu 0.7 Cr 0.5   
                 Amo 
                 418 
                 561 
                 143 
                 12 
                 1.6 
               
               
                 Example 58 
                 Fe 82.3 B 8 Si 4 P 4 Cu 0.7 Cr 1   
                 Amo 
                 420 
                 564 
                 144 
                 14.8 
                 1.56 
               
               
                 Example 59 
                 Fe 81.3 B 8 Si 4 P 4 Cu 0.7 Cr 2   
                 Amo 
                 422 
                 568 
                 146 
                 6.6 
                 1.5 
               
               
                 Example 60 
                 Fe 80.3 B 8 Si 4 P 4 Cu 0.7 Cr 3   
                 Amo 
                 427 
                 574 
                 147 
                 7.4 
                 1.42 
               
               
                 Comparative 
                 Fe 79.3 B 8 Si 4 P 4 Cu 0.7 Cr 4   
                 Amo 
                 430 
                 578 
                 148 
                 13.5 
                 1.34 
               
               
                 Example 26 
               
               
                 Example 61 
                 Fe 81.3 B 8 Si 4 P 4 Cu 0.7 Nb 2   
                 Amo 
                 435 
                 613 
                 178 
                 8.7 
                 1.36 
               
               
                 Example 62 
                 Fe 81.3 B 8 Si 4 P 4 Cu 0.7 Ni 2   
                 Amo 
                 418 
                 553 
                 135 
                 8.1 
                 1.59 
               
               
                 Example 63 
                 Fe 81.3 B 8 Si 4 P 4 Cu 0.7 Co 2   
                 Amo 
                 415 
                 561 
                 146 
                 8.4 
                 1.63 
               
               
                 Example 64 
                 Fe 81.3 B 8 Si 4 P 4 Cu 0.7 Al 1   
                 Amo 
                 426 
                 549 
                 123 
                 13 
                 1.60 
               
               
                   
               
               
                 Amo: Amorphous; Cry: Crystal 
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 18 
               
               
                   
                   
               
               
                   
                 Magnetic 
                   
                   
                 Average 
                 Heat 
               
               
                   
                 Permeability 
                 Hc (A/m) 
                 Bs (T) 
                 Diameter (nm) 
                 Treatment Condition 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Example 56 
                 30000 
                 7 
                 1.88 
                 15 
                 475° C. × 10 Minutes 
               
               
                 Example 57 
                 28000 
                 6.0 
                 1.8 
                 16 
                 475° C. × 10 Minutes 
               
               
                 Example 58 
                 24000 
                 7.2 
                 1.74 
                 17 
                 475° C. × 10 Minutes 
               
               
                 Example 59 
                 27000 
                 6.4 
                 1.71 
                 15 
                 475° C. × 10 Minutes 
               
               
                 Example 60 
                 25000 
                 4.9 
                 1.66 
                 16 
                 475° C. × 10 Minutes 
               
               
                 Comparative 
                 22000 
                 7.0 
                 1.63 
                 16 
                 475° C. × 10 Minutes 
               
               
                 Example 26 
               
               
                 Example 61 
                 23000 
                 5.2 
                 1.68 
                 14 
                 475° C. × 10 Minutes 
               
               
                 Example 62 
                 29000 
                 5.0 
                 1.81 
                 16 
                 450° C. × 10 Minutes 
               
               
                 Example 63 
                 24000 
                 5.4 
                 1.89 
                 14 
                 450° C. × 10 Minutes 
               
               
                 Example 64 
                 16000 
                 9. 
                 1.83 
                 14 
                 450° C. × 10 Minutes 
               
               
                   
               
             
          
         
       
     
         [0050]    As understood from Table 17, each of the alloy compositions of Examples 56-64 has an amorphous phase as a main phase after the rapid cooling process. 
         [0051]    The alloy compositions of Examples 56-64 and Comparative Example 26 listed in Table 18 correspond to the cases where the Fe content is replaced in part with Nb elements, Cr elements, Co elements and Co elements. Each of the alloy compositions of Examples 56-64 listed in Table 18 has magnetic permeability μ of 10,000 or more, saturation magnetic flux density Bs of 1.65 T or more and coercivity Hc of 20 A/m or less. Therefore, a range of from 0 atomic % to 3 atomic % defines a replacement allowable range for the Fe content. The replaced Fe content of Comparative Example 26 is 4 atomic %. The alloy compositions of Comparative Example 26 has low saturation magnetic flux density Bs, which is out of the above-mentioned property range of Examples 56-64. 
       Examples 65-69 and Comparative Examples 27-29 
       [0052]    Materials were respectively weighed so as to provide alloy compositions of Examples 65-69 of the present invention and Comparative Examples 27-29 as listed in Table 19 below and were melted by the high-frequency induction melting process. The melted alloy compositions were processed by the single-roll liquid quenching method under the atmosphere so as to produce continuous strips which have a thickness of 25 μm, a width of 15 or 30 mm and a length of about 10 to 30 m. For each of the continuous strip of the alloy compositions, phase identification was carried out through the X-ray diffraction method. Toughness of each continuous strip was evaluated by the 180 degree bend test. In addition, the alloy compositions of Examples 65 and 66 were exposed to heat treatment processes which were carried out under the heat treatment conditions of 475° C.×10 minutes. Likewise, the alloy compositions of Examples 67 to 69 and Comparative Example 27 were exposed to heat treatment processes which were carried out under the heat treatment conditions of 450° C.×10 minutes, and the alloy composition of Comparative Example 28 was exposed to a heat treatment process which was carried out under the heat treatment condition of 425° C.×30 minutes. Saturation magnetic flux density Bs of each of the heat-treated alloy compositions was measured by using a vibrating-sample magnetometer (VMS) under a magnetic field of 800 kA/m. Coercivity Hc of each alloy composition was measured by using a direct current BH tracer under a magnetic field of 2 kA/m. Core loss of each alloy composition was measured by using an alternating current BH analyzer under excitation conditions of 50 Hz and 1.7 T. The measurement results are shown in Table 19. 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 19 
               
             
             
               
                   
                   
               
               
                   
                 Before 
                 After 
               
               
                   
                 Heat Treatment 
                 Heat Treatment 
               
             
          
           
               
                   
                 Alloy Composition 
                 Width 
                 Phase 
                 180° 
                 Hc 
                 Bs 
                 Pcm 
               
               
                   
                 (at %) 
                 (mm) 
                 (XRD) 
                 Bent Test 
                 (A/m) 
                 (T) 
                 (W/kg) 
               
               
                   
                   
               
             
          
           
               
                 Example 65 
                 Fe 83.3 B 8 Si 4 P 4 Cu 0.7   
                 15 
                 Amo 
                 ∘ 
                 6.4 
                 1.86 
                 0.42 
               
               
                 Example 66 
                 Fe 83.3 B 8 Si 4 P 4 Cu 0.7   
                 30 
                 Amo 
                 ∘ 
                 6.7 
                 1.85 
                 0.45 
               
               
                 Example 67 
                 Fe 84.3 B 8 Si 4 P 3 Cu 0.7   
                 15 
                 Amo 
                 ∘ 
                 8.9 
                 1.88 
                 0.81 
               
               
                 Example 68 
                 Fe 85.3 B 10 Si 2 P 2 Cu 0.7   
                 15 
                 Amo 
                 ∘ 
                 11 
                 1.93 
                 0.81 
               
               
                 Example 69 
                 Fe 84.8 B 10 Si 2 P 2 Cu 1.2   
                 15 
                 Amo 
                 ∘ 
                 8.3 
                 1.90 
                 0.61 
               
               
                 Comparative 
                 Fe 84.5 B 10 Si 2 P 2 Cu 1.5   
                 15 
                 Cry 
                 x 
                 37 
                 1.87 
                 1.73 
               
               
                 Example 27 
               
               
                 Comparative 
                 Fe Amorphous 
                 15 
                 Amo 
                 ∘ 
                 8 
                 1.55 
                 Not 
               
               
                 Example 28 
                   
                   
                   
                   
                   
                   
                 Excited 
               
               
                 Comparative 
                 Grain-Oriented 
                   
                   
                   
                 23 
                 2.01 
                 1.39 
               
               
                 Example 29 
                 Electrical Steel Sheet 
               
               
                   
               
               
                 Amo: Amorphous; Cry: Crystal 
               
             
          
         
       
     
         [0053]    As understood from Table 19, each of the alloy compositions of Examples 65-69 has an amorphous phase as a main phase after the rapid cooling process and is capable of being flat on itself upon the 180 degree bend test. 
         [0054]    In addition, each of the Fe-based nano-crystalline alloys obtained by heat treating the alloy compositions of Examples 65-69 has saturation magnetic flux density Bs of 1.65 T or more and coercivity Hc of 20 A/m or less. Furthermore, each of the Fe-based nano-crystalline alloys of Examples 65-69 can be excited under the excitation condition of 1.7 T and has lower core loss than that of an electrical steel sheet. Therefore, the use thereof can provide a magnetic component or device which has a low energy-loss property. 
       Examples 70-74 and Comparative Examples 30, 31 
       [0055]    Materials of Fe, Si, B, P and Cu were respectively weighed so as to provide alloy compositions of Fe 84.8 B 10 Si 2 P 2 Cu 1.2  and were melted by the high-frequency induction melting process. The melted alloy compositions were processed by the single-roll liquid quenching method under the atmosphere so as to produce continuous strips which have a thickness of about 25 μm, a width of 15 mm and a length of about 30 m. As a result of phase identification by the X-ray diffraction method, each of the continuous strip of the alloy compositions had an amorphous phase as its main phase. In addition, each continuous strip could be flat on itself upon the 180 degree bend test. Thereafter, the alloy compositions were exposed to heat treatment processes which were carried out under the heat treatment conditions where the holder was laid under 450° C.×10 minutes and their temperature increase rate was in a range of from 60 to 1200° C. per minute. Thus, the sample alloys of Examples 70-74 and Comparative Example 30 were obtained. Also, a grain-oriented electrical steel sheet was prepared as Comparative Example 31. Saturation magnetic flux density Bs of each of the heat-treated alloy compositions was measured by using a vibrating-sample magnetometer (VMS) under a magnetic field of 800 kA/m. Coercivity Hc of each alloy composition was measured by using a direct current BH tracer under a magnetic field of 2 kA/m. Core loss of each alloy composition was measured by using an alternating current BH analyzer under excitation conditions of 50 Hz and 1.7 T. The measurement results are shown in Table 20. 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 20 
               
               
                   
                   
               
               
                   
                 Rate of Temperature Increase 
                 Hc 
                 Bs 
                 Pcm 
               
               
                   
                 (° C./Minutes) 
                 (A/m) 
                 (T) 
                 (W/kg) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Example 70 
                 1200 
                 14.6 
                 1.86 
                 0.62 
               
               
                 Example 71 
                 600 
                 11.9 
                 1.91 
                 0.63 
               
               
                 Example 72 
                 400 
                 14.1 
                 1.90 
                 0.64 
               
               
                 Example 73 
                 300 
                 12.4 
                 1.89 
                 0.61 
               
               
                 Example 74 
                 100 
                 18 
                 1.92 
                 0.81 
               
               
                 Comparative 
                 60 
                 64.5 
                 1.93 
                 1.09 
               
               
                 Example 30 
               
               
                 Comparative 
                 (Grain-Oriented 
                 23 
                 2.01 
                 1.39 
               
               
                 Example 31 
                 Electrical Steel Sheet) 
               
               
                   
               
             
          
         
       
     
         [0056]    As understood from Table 20, each of the Fe-based nano-crystalline alloys obtained by heat treating the alloy compositions of Examples 65-69 under temperature increase rate of 100° C. per minute or more has saturation magnetic flux density Bs of 1.65 T or more and coercivity Hc of 20 A/m or less. Furthermore, each of the Fe-based nano-crystalline alloys can be excited under the excitation condition of 1.7 T and has lower core loss than that of an electrical steel sheet. 
       Examples 75-78 and Comparative Examples 32, 33 
       [0057]    Materials of Fe, Si, B, P and Cu were respectively weighed so as to provide alloy compositions of Fe 83.8 B 8 Si 4 P 4 Cu 0.7  and were melted by the high-frequency induction melting process to produce a master alloy. The master alloy was processed by the single-roll liquid quenching method so as to produce a continuous strip which has a thickness of about 25 μm, a width of 15 mm and a length of about 30 m. The continuous strip was exposed to a heat treatment process which was carried out in an Ar atmosphere under conditions of 300° C.×10 minutes. The heat-treated continuous strip was crushed to obtain powders of Example 75. The powders of Example 75 have diameters of 150 μm or smaller. In addition, the powders and epoxy resin were mixed so that the epoxy resin was of 4.5 weight %. The mixture was put through a sieve of 500 μm mesh so as to obtain granulated powders which had diameters of 500 μm or smaller. Then, by the use of a die that had an inner diameter of 8 mm and an outer diameter of 13 mm, the granulated powders were molded under a surface pressure condition of 7,000 kgf/cm 2  so as to produce a molded body that had a toroidal shape of 5 mm height. The thus-produced molded body was cured in a nitrogen atmosphere under a condition of 150° C.×2 hours. Furthermore, the molded body and the powders were exposed to heat treatment processes in an Ar atmosphere under a condition of 450° C.×10 minutes. 
         [0058]    Materials of Fe, Si, B, P and Cu were respectively weighed so as to provide alloy compositions of Fe 83.8 B 8 Si 4 P 4 Cu 0.7  and were melted by the high-frequency induction melting process to produce a master alloy. The master alloy was processed by the water atomization method to obtain powders of Example 76. The powders of Example 76 had an average diameter of 20 μm. Furthermore, the powders of Example 76 were subjected to air classification to obtain powders of Examples 77 and 78. The powders of Example 77 had an average diameter of 10 μm, and the powders of Example 78 had an average diameter of 3 μm. The above-mentioned powders of each Example 76, 77, or 78 were mixed with epoxy resin so that the epoxy resin was of 4.5 weight %. The mixture thereof was put through a sieve of 500 μm mesh so as to obtain granulated powders which had diameters of 500 μm or smaller. Then, by the use of a die that had an inner diameter of 8 mm and an outer diameter of 13 mm, the granulated powders were molded under a surface pressure condition of 7,000 kgf/cm 2  so as to produce a molded body that had a toroidal shape of 5 mm height. The thus-produced molded body was cured in a nitrogen atmosphere under a condition of 150° C.×2 hours. Furthermore, the molded body and the powders were exposed to heat treatment processes in an Ar atmosphere under a condition of 450° C.×10 minutes. 
         [0059]    Fe-based amorphous alloy and Fe—Si—Cr alloy were processed by the water atomization method to obtain powders of Comparative Examples 32 and 33, respectively. The powders of each of Comparative Examples 32 and 33 had an average diameter of 20 μm. Those powders were further processed, similar to Examples 75-78. 
         [0060]    By using a differential scanning calorimetry (DSC), calorific values of the obtained powders upon their first crystallization peaks were measured and, then, were compared with that of the continuous strip of a single amorphous phase so that each amorphous rate, i.e. a rate of the amorphous phase in each alloy, was calculated. Also, saturation magnetic flux density Bs and coercivity Hc of each of the heat-treated powder alloys was measured by using a vibrating-sample magnetometer (VMS) under a magnetic field of 800 kA/m. Core loss of each molded body was measured by using an alternating current BH analyzer under excitation conditions of 300 kHz and 50 mT. The measurement results are shown in Table 21. 
         [0000]    
       
         
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 21 
               
               
                   
                   
               
               
                   
                   
                   
                 Average 
                 Amorphization 
                   
                   
                 Average 
                   
               
               
                   
                   
                   
                 Diameter of 
                 Ratio for 
                 Bs of 
                 Hc of 
                 Diameter of 
                 Pcv of 
               
               
                   
                   
                   
                 Powder Particle 
                 Pre-HTPP 
                 Post-HTPP 
                 Post-HTPP 
                 Post-HTNC 
                 Post-HTM 
               
               
                   
                 Alloy Composition 
                 Method 
                 (μm) 
                 (%) 
                 (T) 
                 (A/m) 
                 (nm) 
                 (mW/cc) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Example 75 
                 Fe 83.3 Si 4 B 8 P 4 Cu 0.7   
                 Single Roll + 
                 32 
                 100 
                 1.86 
                 28 
                 17 
                 1350 
               
               
                   
                   
                 Crush 
               
               
                 Example 76 
                   
                 Water 
                 20 
                 40 
                 1.81 
                 52 
                 23 
                 2000 
               
               
                   
                   
                 Atomization 
               
               
                 Example 77 
                   
                 Water 
                 10 
                 65 
                 1.84 
                 48 
                 19 
                 1650 
               
               
                   
                   
                 Atomization 
               
               
                 Example 78 
                   
                 Water 
                 3 
                 100 
                 1.82 
                 32 
                 16 
                 1240 
               
               
                   
                   
                 Atomization 
               
               
                 Comparative 
                 Fe-Based 
                 Water 
                 20 
                 — 
                 1.20 
                 60 
                 — 
                 1900 
               
               
                 Example 32 
                 Amorphous 
                 Atomization 
               
               
                 Comparative 
                 Fe—Si—Cr (Crystal) 
                 Water 
                 20 
                 — 
                 1.68 
                 96 
                 — 
                 2100 
               
               
                 Example 33 
                   
                 Atomization 
               
               
                   
               
               
                 Pre-HTPP: Pre-Heat-Treatment Powder Particle; Post-HTPP: Post-Heat-Treatment Powder Particle; Post-HTNC: Post-Heat-Treatment Nano-Crystal; Post-HTM: Post-Heat-Treatment Molding 
               
             
          
         
       
     
         [0061]    As understood from Table 21, each of the alloy compositions of Examples 75-78 has nanocrystals posterior to the heat treatment processes, wherein the nanocrystals have an average diameter 25 nm or smaller for each of Examples 75-78. In addition, each of the alloy compositions of Examples 75-78 has high saturation magnetic flux density Bs and low coercivity Hc in comparison with Comparative Examples 32, 33. Each of dust cores formed by using the respective powders of Examples 75-78 also has high saturation magnetic flux density Bs and low coercivity Hc in comparison with Comparative Examples 32, 33. Therefore, the use thereof can provide a magnetic component or device which is small-sized and has high efficiency. 
         [0062]    Each alloy composition may be partially crystallized prior to a heat treatment process, provided that the alloy composition has, posterior to the heat treatment process, nanocrystals having an average diameter of 25 nm. However, as apparent from Examples 76-78, it is preferable that the amorphous rate is high in order to obtain low coercivity and low core loss. 
         [0063]    The present application is based on a Japanese patent application of JP2008-214237 filed before the Japan Patent Office on Aug. 22, 2008, the contents of which are incorporated herein by reference. 
         [0064]    While there has been described what is believed to be the preferred embodiment of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such embodiments that fall within the true scope of the invention.

Technology Classification (CPC): 7