POWDERY ALLOY FOR BONDED MAGNET AND BONDED MAGNET

Abstract: A flame-retardant bonded magnet which does not contain cobalt, the use of which is restricted from the viewpoint of resources saving, and is excellent in the temperature characteristics optimal for a display and the convergence yoke of the cathode ray tube of a high-definition television; and a powdery alloy therefor which is composed of a Co-free Al-Ni-Cu-(Ti, Nb)-Fe system, is isotropic, and has a mean particle diameter of 10 to 200 µm. This magnet can be produced at a low cost by milling 20-80 wt.% of the alloy, a chlorinated flame retardant, a flame-retardant aid such as antimony trioxide or zinc borate, and a binder, followed by shaping and solidification.

Description: TECHNICAL FIELD The present invention relates to powdered alloys for use in the manufacture of bonded magnets which can be molded into various shapes, to bonded magnets and their compositions and use, with particular regard to a flame retardant bonded magnet and particularly, to powdered alloys for bonded magnets which enable the obtaining of bonded magnets having superior temperature characteristics, that is, magnets consisting mainly of Fe-Al-Ni-Cu having a specific composition and a flame retardant binder such as a halogen type flame retardant, and the bonded magnet. BACKGROUND ART A bonded magnet is typically manufactured by molding a compound prepared by mixing and kneading magnetic alloy powders of desired compositions with resins, a flame retardant, and any other materials into various shapes by means of injection molding, compression molding, or extrusion molding so that thin and complicated shapes can be easily manufactured and uniform characteristics obtained without cracks or chips, and hence such magnets are widely used in magnetic circuits of electronic components in audio equipment, OA (optical/audio) equipment and the like. Conventionally though a ferrite magnet powder or a rare earth magnet powder are generally used as the magnet powders for bonded magnets and Alnico magnet alloy powders are also used in focusing magnets for focusing electron beams and in adjusting convergence in picture tubes in television or display Braun tubes because of (1) superlative temperature characteristics (2) a higher saturated magnetic flux density than ferrite magnetic powder, and a superior resistance to oxidation and weathering as compared with rare earth magnetic powders. As the Alnico magnet, Alnico 8 having a coercive force of 1000 Oe or more and Alnico 5 having the coercive force of about 500 to 700 Oe are well known, both having low temperature change of magnet characteristics of 0.05%/°C or less. The inventor has previously proposed bonded magnets of Alnico 5 and Alnico 8 (Japanese Patent Application Laid Open No. Hei 4-239103) and an Alnico bonded magnet is also disclosed in the Japanese Patent Application Laid Open Nos. Hei 3-239306 and Hei 3-259502. However since the Alnico type magnet alloys consisting of Alnico 5 and Alnico 8 all contain a large amount of Co, about 25% to 40%, there was the possibility of high product cost and a lack of uncertainty in the supply of raw materials, all due to the scarcity and high cost of Co. Also, though fire resistance is required for a resin-bonded magnet used in domestic appliances and the OA equipment, some products using a brominated flame retardant can produce dioxine, which is toxic, on burning, thus the regulation of its use is being considered in U.S.A. and Europe. It is an object of the present invention to provide alloy powders for bonded magnet which does not contain high proportions of cobalt, and need not contain any, and which is composed mainly of Fe-Ni-Al-Cu, having good temperature characteristics, and to provide a resin-bonded magnet containing a flame retardant which is safe at disposal and on combustion such as a fire. DISCLOSURE OF THE INVENTION In the present invention, as a result of various studies made on alloy compositions which do not contain expensive Co such as Alnico 5 and Alnico 8 as a bonded magnet, used. for example, for controlling beams of picture tubes in color televisions and display Braun tubes, while making a good use of a low temperature coefficient in variations of the magnetic characteristics, we have found that it is possible to use, in place of the costly Co-containing Alnico types, specific compositions which contain little or substantially no Co when pulverized into desired particle sizes. Also, as a result of various studies on blending for fire resistance of the bonded magnet, by incorporating specific flame retardants, bonded magnets can be obtained with a fire resistance qualified by the combustion test of UL-94 Vo, and with reduced possibility of giving off toxic substances such as dioxine. The powdered alloys for use in forming a bonded magnet of the present invention are characterized by comprising, all by weight of the alloy powder 10 % to 16 % Al, 23 % to 33 % Ni, 2 % to 8 % Cu, Ti or Nb or both in a total amount of 1.5 to 5%, and Si in an amount of 0.01 to 0.5%, and optionally comprising Co in an amount of up to 5%, the balance of said powder being Fe and any unavoidable impurities, and the alloy exhibiting isotropy and the powder having a mean particle size of from 10 µm to 200 µm. The present invention also proposes various advantageous and optional features which are set forth in the dependent claims included in this specification. Alloy powders for bonded magnets which contain 0.5 wt% to 5.0 wt% of one or both of Ti and Nb can be mechanically pulverized easily. The present invention is directed to a bonded magnet which is flame retardant and contains a powder as aforesaid and a binder. The present invention also proposes, in the above-mentioned composition of the bonded magnet, a composition containing 20 wt% to 98 wt% alloy powders, a composition containing 20 wt% to 80 wt% alloy powders, a composition which contains 5 wt% to 50 wt% flame retardant, and is most suitable for convergence use, a bonded magnet containing 2 to 45% silicate of components other than the alloy powders as an inorganic filler, and a bonded magnet having 150 G to 1300 G Br, 150 Oe to 500 Oe iHc and 0.01 MGOe to 0.15 MGOe(BH)max, and 0.07 %/°C or less temperature coefficient of magnetic property. In the present invention, by forming an isotropic permanent magnet body by melting the alloy having the above-mentioned compositions for predetermined heat treatment, and pulverizing the alloy into powder having the mean particle sizes of 10 µm to 200 µm, it is possible to obtain Fe-Ni-Al-Cu magnet powders which are most suitable for use in bonded magnets and have a good magnetic properties and temperature characteristics. Though a so-called Alnico magnet such as Alnico 5 and Alnico 8 contains, 7 to 10 wt% Al, 12 to 18 wt% Ni, 5 to 40 wt% Co and 1 to 8 wt% Cu as the essential compositions, and is further supplemented with % Ti, Nb, Si and the like, according to the present invention, the superior magnetic property is obtained by increasing the contents of Al and Ni even though Co, which is a rather scarce commodity, is not required, and by containing a predetermined amount of Cu, Ti and Nb to improve heat treatment and grindability, alloy powders for bonded magnets and bonded magnets using said powders which are technically valuable can be realized. BEST MODE FOR CARRYING OUT THE INVENTION In the following, there is a brief discussion of compositions of alloy powders for bonded magnets and bonded magnets according to the present invention. Al is essential for obtaining superior magnet characteristics without using Co, and it is used in an amount of 10 wt% to 16 wt%, because coercive force will drop when less than 10 wt% is used, and both the coercive force and a residual magnetic flux density are lowered when more than 16 wt% is used. Ni is an essential composition for obtaining superior magnetic characteristics without using Co, and it is preferably used in an amount of 23 wt% to 33 wt%, because coercive force will drop when less than 23 wt% is used, and the residual magnetic flux density is lowered when more than 33 wt% is used. Cu is preferably between 2 wt% and 8 wt%, because coercive force as well as residual magnetic flux density are lowered within the range of heat treatment conditions to be described later, when below 2 wt% or above 8 wt% are used. Ti and Nb are added to improve the residual magnetic flux density and grindability. If more than 5 wt% each of Ti and Nb are added, or when adding the two in an amount more than 5 wt% in total, the residual magnetic flux density is lowered. Grinding efficiency is promoted by the use of a combined (Ti + Nb) content of at least 1.5 wt%. Thus, in accordance with the invention, a combined (Ti + Nb) content of 1.5 wt% to 5 wt% is used. Fe is a nucleus for Fe-Ni-Al-Cu and constitutes a balance of the powder composition after certain optional ingredients are taken into account. Besides the above-mentioned essential compositions, Si is effective in improving, particularly, a cooling speed from fusing temperature in the heat treatment and a castability, thus it is added in an amount of 0.01 wt% to 0.5 wt%. Co is, basically, not an essential component of the present invention, mainly because of its cost. However, sometimes it is mixed by utilizing scrap material if such is available. Containing Co itself does not exert negative effects on the magnetic properties, but when it is used in a large amount, a low cost product can not be achieved, and so the Co content is preferably kept below 5 wt% or even below 0.5%. Alloy powders for bonded magnets according to the present invention having mean particle sizes of 10 µm to 200 µm can be manufactured by well known grinding methods such as by using a jaw crusher, a ball mill and the like, after two-stage heat treatments of fusing at 900°C to 1200°C and aging at 500°C to 700°C of an alloy (an ingot) prepared by the high-frequency dissolution at a temperature of, for example, 1600°C to 1700°C. In the alloy powders of the present invention, it is not preferable if the mean particle size is below 10 µm, because the grinding cost is too high and, at the same time, coercive force becomes lower, and since the moldability and uniformity of the bonded magnet deteriorate when the mean particle size is above 200 µm, the mean particle size is within the range of 10 µm to 200 µm. As methods of obtaining the alloy powders, not only the ingot obtained by dissolution be ground, but as long as the particle size is within the range of 10 µm to 200 µm, other well known comminuting methods such as atomizing by injection of gas or water for pulverization after dissolution, may be selected if desired. Also, heat treatments such as fusing and aging need not be performed independently, they may be performed continuously by controlling the cooling after dissolution. As a method for manufacturing the bonded magnet of the present invention a composition containing 20 wt% to 98 wt% of alloy powders having the aforementioned compositions and a binder are mixed, and molded into a predetermined shape by the molding methods such as the injection molding, compression molding extrusion molding and the like. The amount of alloy powders is preferably 20 wt% to 98 wt%, because the magnetic property of the bonded magnet is lowered when below 20 wt% is used, and it is difficult to mold into a bonded magnet when above 98 wt%is used. In particular, 20 wt% to 80 wt% is preferable for convergence use in cathode ray tubes. In order to obtain a resin-bonded magnet having a high fire resistance, a predetermined amount of flame retardant may be mixed besides the alloy powders and the resin binder, and the same methods as stated above may be adopted. The flame-retardant used may be a halogenated flame retardant or a non- halogenated flame retardant. As halogenated flame retardant, those of bromine type such as decabromo-diphenyloxide, pentabromo-diphenyloxide, ethylene bistetrabromo-phthalamide, dibromo-neopentyl glycol and the like, and of chlorine type such as chlorinated paraffin, chlorinated polyphenyl, perchlorpentacyclodecane, dichloranplus, chlorinated diphenyl and the like may be used. Also, those prepared adding 5 wt% to 25 wt% of flame retardant assistants such as synergist of antimony trioxide, additives of zinc boric acid, zinc chloride and the like to these flame retardants may also be used. Since some of the bromine type flame retardants are prone to produce toxic dioxine at the time of disposition and combustion at a fire, it is particularly preferable to use chlorinated flame retardants, which are to be added in an amount of 5 wt% or more to obtain the fire resistance of UL-94 Vo. When the amount of additive exceeds 50 wt%, the moldability is deteriorated and also the cost increases, and hence 5 wt% to 50 wt% is the preferred range. As the bromine type flame retardants, ethylene bistetrabromo-phthalmide (not pentabromodiphenyloxide, octabromodiphenyl-oxide or decabromo-diphenyl-oxide which are prone to produce dioxane) is preferable, and the amount of additive is preferably 5 to 20 wt%. Non-halogen flame retardants containing no halogen elements such as bromine and chlorine, but containing alumina hydrate and magnesia hydrate can be used. As binder, thermoplastic resins such as nylon, polypropylene, polyethylene. polyvinyl chloride, polyphenylene sulfide and the like, thermosetting resins such as phenol resin, epoxy resin and the like, or metal binders such as Al, Zn, Sn, Pb and so on can be selected suitably. In order to mix and knead the binder, flame retardant and alloy powders and a lubricant may be added or pretreatment may be performed. It is also efficacious, for improving thermal resistance and strength, to replace a part of flame retardant (including the flame retardant assistant) and/or binder with an inorganic filler consisting of silicates such as magnesium silicate, calcium silicate and the like, and the amount of additive of 2% or more of the components other than the alloy powders is effective, but it is not preferable above 45% because then the moldability is worsened. The alloy powders for bonded magnets of the present invention have properties of: 5 KG or more Br; 500 Oe or more iHc; and 1 MGOe or more (BH) Max, and by mixing the alloy powders, binder, flame retardant and so on at a predetermined mixing ratio, the bonded magnets of the present invention shows properties of 200 G or more Br, 150 Oe or more iHc, 0.01 MGOe or more (BH) max and 0.07%/°C or less temperature coefficient of Br, particularly, bonded magnets containing 20 wt% to 80 wt% alloy powders show the high characteristics of 150 G to 1300 G Br, 150 Oe, to 500 Oe iHc, 0.01 MGOe to 0.15 MGOe (BH) max and 0.03%/°C to 0.05%/°C temperature coefficient of Br, and is most suitable for convergence use in cathode ray tubes. EMBODIMENT 1 Magnetic powders are obtained by pulverizing, in a ball mill for 10 hours, alloys having the compositions shown in Table 1 which were dissolved using a high-frequency smelting furnace, and fused at 1200°C for 15 minutes, aged at 550°C for 24 hours and further crushed to 35 meshes or less with a jaw crusher. Magnetic properties and grindability of these powders are shown in Table 2. The grindability is shown by yields of the powders passing through 100 meshes. In Table 1 and Table 2 Samples Nos. 1-1 to 1-5 represent the present invention and Sample Nos. 1-6 to 1-13 represent comparative examples. As it is apparent from Table 2, in the case of alloy powders whose Al content is below 10 wt% such as the comparative example 1-9, or in the case of alloy powders whose Ni content is above 33 wt%, such as the comparative example 1-10, the magnetic characteristics are relatively poor as compared with the alloy powders according to the present invention. Also, though the magnetic properties of the alloy powders shown in the comparative examples 1-11 to 1-13 surpass those of the present invention, since a large amount of Co which is costly and scarce in resources is contained, the product is difficult to provide at low cost. Furthermore, the alloy powders of the compositions shown in Samples 1-6 to 1-8 have low totals of (Ti + Nb) and do not exhibit such good grindability as is shown by Samples 1-1 to 1-5. Sample Nos Alloy Compositions (wt%) Al Ni Cu Ti Nb Si Co Fe Present Invention 1-1 11.0 26.0 4.0 1.5 - 0.1 - 57.4 1-2 13.0 25.0 3.0 2.5 - 0.05 - 56.45 1-3 12.0 29.0 4.0 - 1.5 0.15 - 53.35 1-4 13.0 30.0 5.0 3.0 1.5 0.1 - 47.4 1-5 13.0 26.0 7.0 0.5 1.0 0.2 - 52.3 Comparative Example 1-6 13.0 25.0 4.0 0.2 - 0.3 - 57.7 1-7 12.0 25.0 4.0 0.3 - 0.1 - 58.6 1-8 13.0 26.0 4.0 - 0.4 0.15 - 56.45 1-9 9.0 21.0 3.0 2.0 - 0.1 - 64.9 1-10 15.0 35.0 4.0 - 3.0 0.1 - 42.9 1-11 8.0 14.0 3.0 0.1 - 0.6 24.0 50.3 1-12 7.0 14.0 3.0 5.5 - 0.1 35.0 35.4 1-13 7.0 18.0 3.0 4.0 2.0 0.1 25.0 40.9 Sample Nos Magnetic Property Grindability Br (G) iHc (Oe) (BH)max (MGOe) Present Invention 1-1 6.5 605 1.6 40 1-2 6.3 650 1.5 50 1-3 5.6 640 1.3 55 1-4 5.1 750 1.1 70 1-5 5.3 550 1.2 60 Comparative Example 1-6 6.3 590 1.3 3 1-7 6.3 600 1.4 10 1-8 6.1 580 1.2 5 1-9 6.7 450 0.9 - 1-10 4.8 490 0.6 - 1-11 13.0 600 5.5 - 1-12 9.0 1500 5.5 - 1-13 7.0 1100 2.3 - EMBODIMENT 2 To the alloy powders of the present invention of the composition of Sample No. 1-2 of the Embodiment 1, nylon 6 powder was added as a binder, brominated type ethylene bistetrabromo-phthalamide was added as a flame retardant and antimony trioxide was added as an auxiliary flame retardant to give the compositions shown in Samples nos. 2-1 to 2-3 in Table 3. These ingredients were mixed in a V mixer for 30 minutes and then kneaded in a kneader for 10 minutes with heating at 250°C to obtain pellets. The pellets were further molded by an injection molding machine at 280°C to obtain a 10 mm × 10 mm × 5 mm molding for measurement of magnetic properties, and a 12.7 mm × 12.7 mm × 0.8 mm molding for measurement of fire resistance. Evaluations on the magnetic properties and fire resistance of the bonded magnet are shown in Table 4. The fire resistance evaluation was judged by carrying out the vertical firing test according to JIS K6911 heat resistant test B to pass or fail a V-o classification of fire resistance. The magnetic characteristic evaluation was judged by convergence properties after preparing the magnet for convergence use. Since the Sample No. 2-3 has a relatively little content of the flame retardant and flame retardant assistant as compared with Samples 2-1 and 2-2, though it does not pass the V-o class as to thermal resistance, its magnetic properties are equal, thus by using it in circumstances not requiring a high thermal resistance, other advantages of the present invention can be realized. Also in the following embodiments, as to those marked with an asterisk on the sample numbers, the alloy powders, binder, flame retardant, flame retardant assistant, inorganic filler and so on are not necessarily contained at a proper amount, and the magnetic properties and fire resistance are relatively low as compared with the other samples. However, similar to the Sample No. 2-3* by selecting their use, some advantages afforded by the present invention can be realized. EMBODIMENT 3 Bonded magnets were prepared by the same method as Embodiment 2, except using nylon 6 powder as a binder and dichloranplus as a chlorinated flame retardant, and using antimony trioxide as a flame retardant assistant A and zinc chloride as a flame retardant assistant B by blending compositions shown in Table 3. Evaluations on magnetic properties and fire resistance of the bonded magnet are shown in Table 4. The fire resistance was evaluated by the same method as the embodiment 2. The magnet properties were evaluated on convergence properties after preparing the magnet for convergence use. Sample Nos Blending Compositions (wt%) Alloy Powders Resin Fire Retardant Fire Retardant Assistant A B Embodiment 2 2-1 50.0 23.0 22.0 5.0 - 2-2 50.0 15.0 25.0 10.0 - 2-3* 50.0 28.0 18.0 4.0 - Embodiment 3 3-1 50.0 20.0 13.0 15.0 2.0 3-2 30.0 28.0 21.0 19.0 3.0 3-3 40.0 25.0 16.0 17.0 2.0 3-4 60.0 15.0 18.0 6.0 1.0 3-5 70.0 10.0 12.0 7.0 1.0 3.6* 15.0 35.0 29.0 18.0 3.0 3.7* 70.0 20.0 4.0 5.0 1.0 Sample Nos Magnetic Property Evaluation on Magnet Property Evaluation on flame retardancy Br (G) iHc (Oe) (BH)max (MGOe) Embodiment 2 2-1 370 250 0.03 good qualified 2-2 410 270 0.03 good qualified 2-3 420 260 0.03 good not qualified Embodiment 3 3-1 530 300 0.04 good qualified 3-2 210 160 0.01 good qualified 3-3 340 230 0.02 good qualified 3-4 850 360 0.08 good qualified 3-5 1210 430 0.14 good qualified 3-6 130 110 0.005 poor qualified 3-7 830 370 0.07 good not qualified EMBODIMENT 4 Bonded magnets were prepared by the same method as Embodiment 2, except magnesium silicate (a talc) was added as an inorganic filler, in the blending compositions shown in Table 5, to the same binder, fire retardant and fire retardant assistant as the Embodiment 3. Evaluations of magnetic characteristics, injection moldability and fire resistance of the bonded magnet are shown in Table 6. The injection moldability was evaluated by judging as good or poor of the injection molding of the embodiment. The flame retardancy was evaluated by the same method as Embodiment 2. EMBODIMENT 5 Bonded magnets were prepared by the same method as Embodiment 2, by using the same flame retardant and auxiliary flame retardant as Embodiment 3, using a block copolymer of propylene powders of 450 µm mean particle sizes as a resin, and using calcium silicate (wollastonite) as an inorganic filler, except the blending compositions shown in Table 5. Evaluation of magnetic characteristics, injection moldability and fire resistance of the bonded magnet are shown in Table 6. The injection moldability was evaluated by judging as good or poor of the injection molding of the embodiment. The flame retardancy was evaluated by the same method as the Embodiment 2. Sample Nos Blending Compositions (wt%) Alloy Powders Resin Flame Retardant Flame Retardant Assistant Inorganic Filler A B Embodiment 4 4.1 30.0 21.0 15.0 4.0 1.0 29.0 4.2 40.0 15.0 16.0 5.0 1.0 23.0 4.3 50.0 13.0 12.0 3.0 2.0 20.0 Embodiment 5 4.4* 30.0 5.0 12.0 3.0 1.0 49.0 4.5* 30.0 15.0 4.0 2.0 2.0 47.0 4.6* 30.0 10.0 55.0 4.0 1.0 - 5-1 30.0 18.0 17.0 5.0 1.0 29.0 5-2 40.0 15.0 15.0 4.0 2.0 24.0 5-3 50.0 14.0 13.0 4.0 2.0 17.0 5-4* 30.0 20.0 4.0 3.0 1.0 42.0 Sample Nos Magnetic Property Evaluation on Injection Moldability Evaluation on flame retardancy Br (G) iHc (Oe) Embodiment 4 4-1 220 170 good qualified 4-2 430 250 good qualified 4-3 610 320 good qualified Embodiment 5 4-4* - - poor - 4-5* 240 180 good not qualified 4-6* - - poor - 5-1* 205 160 good qualified 5-2 410 230 good qualified 5-3 580 310 good qualified 5-4* 260 190 good not qualified EMBODIMENT 6 A bonded magnet was prepared by adding 3 wt% epoxy resin to the alloy powders of the present invention, Sample No. 1-1 of the Embodiment 1, and curing at 150°C for one hour after mixing and compression molding. This bonded magnet of the present invention has superior properties of 2.8 kG Br, 570 Oe iHc, and 0.5 MGOe (BH) max. INDUSTRIAL APPLICABILITY In the present invention, alloy powders for bonded magnets having, high magnetic properties can be obtained without using Co which is expensive and scarce, by using compositions of Al-Ni-Cu-(Ti, Nb)-Fe containing no Co; and by kneading, molding and curing the alloy powders for bonded magnets together with a chlorine flame retardant, flame retardant assistants such as antimony trioxide and zinc boric acid and a binder, the flame retardant bonded magnet having superior temperature properties and, particularly most suitable for convergence use in picture tubes for display and high precision television can be provided at low cost. Also, some embodiments of the bonded magnet of the present invention are free from discharging toxic dioxane on buring, and have a high industrial value

Claims: A powdered alloy for use in forming a bonded magnet which comprises, all by weight of the alloy powder 10 % to 16 % Al, 23 % to 33 % Ni, 2 % to 8 % Cu, Ti or Nb or both in a total amount of 1.5 to 5%, and Si in an amount of 0.01 to 0.5%, and optionally comprises Co in an amount of up to 5%, the balance of said powder being Fe and any unavoidable impurities, and the alloy exhibiting isotropy and the powder having a mean particle size of from 10 µm to 200 µm. An alloy powder according to claim 1, wherein the alloy powder contains less than 5 wt% Co. An alloy powder according to claim 2, wherein the alloy powder contains less than 0.5 wt% Co. An alloy powder in accordance with any preceding Claim, wherein the coercive force (iHc) is 500 Oe or more. A composition for use in the production of a bonded magnet comprising a magnetic alloy powder according to any preceding claim and a binder. A composition for use in the production of a bonded magnet in accordance with claim 5, containing 20 wt% to 98 wt% alloy powders. A composition for use in the production of a bonded magnet in accordance with claim 6, containing 20 wt% to 80 wt% alloy powders. A composition for use in the production of a bonded magnet in accordance with any of claims 5 to 7, in which said binder is a resin binder and which contains 5 wt% to 50 wt% of a flame retardant. A composition for use in the production of a bonded magnet in accordance with claim 8, wherein said flame retardant is a chlorinated flame retardant or a brominated flame retardant. A composition for use in the production of a bonded magnet according to claim 9, wherein said flame retardant is selected from: chlorinated paraffin , chlorinated polyphenyl, perchlorpentacyclodecane, dichloranplus, chlorinated diphenyl. A composition for use in the production of a bonded magnet in accordance with claim 8, wherein said flame retardant is a non-halogen flame retardant. A composition for use in the production of a bonded magnet in accordance with any of claims 8 to 11, which contains 5 wt% to 25 wt% of an auxiliary flame retardant. A composition for use in the production of a bonded magnet in accordance with claim 12, wherein said auxiliary flame retardant assistant consists of, at least one of: antimony trioxide, zinc boric acid, and zinc chloride. A composition for use in the production of a bonded magnet in accordance with any of claims 5 to 13, wherein such composition includes an inorganic filler in an amount of 2% to 45% by weight of components other than alloy powders. A composition for use in the production of fire-resistant resin-bonded magnets according to claim 14, wherein such inorganic filler substantially consists of one or more silicates. A bonded magnet having a composition according to any one of claims 5 to 15. A bonded magnet according to claim 16, wherein the magnet properties are residual magnetic flux density (Br) 200 G or more coercive force (iHc) 150 Oe or more maximum energy product ((BH)max) 0.01 MGOe or more A bonded magnet according to claim 16 or 17, and wherein the residual magnetic flux density (Br) of the magnet has a temperature coefficient below 0.07 %/°C. A bonded magnet according to claims 17 and 18, and wherein such magnet properties each have a temperature coefficient below 0.07 %/°C. Use of a magnet according to any of claims 16 to 19 for controlling electron beams in a cathode ray tube.

Inventors: FURUKAWA TOSHIHIRO, KITAYAMA HIROKAZU, NISHINO YOSHIHIKO, YAMASHITA MICHIO, FURUKAWA, TOSHIHIRO, KITAYAMA, HIROKAZU, NISHINO, YOSHIHIKO, YAMASHITA, MICHIO, FURUKAWA, TOSHIHIRO 43, NAKAGAWACHO 3-CHOME, KITAYAMA, HIROKAZU 1-10, ANDOJICHO 2-CHOME, NISHINO, YOSHIHIKO 46-23, KATAYAMACHO 4-CHOME, YAMASHITA, MICHIO 10, YOKOBAYASHI ENMYOJI
Applicants: SUMITOMO SPEC METALS, SUMITOMO SPECIAL METALS COMPANY LIMITED
Application year: 1993
Main classification: B22F1
IPC codes: H01F1, C22C33, C22C38, B22F1