Patent Publication Number: US-2022221359-A1

Title: Pressure sensor ceramic material and preparation method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The application claims priority to Chinese patent application No. 202110028583.9, filed on Jan. 11, 2021, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure belongs to the technical field of sensor ceramics, in particular to a pressure sensor ceramic material and a preparation method thereof. 
     BACKGROUND 
     Material is the substance foundation of human production and life, and is the symbol of human progress and human civilization. With the emergence and development of new technologies such as space technology, photoelectric technology, infrared technology, sensing technology and energy technology, materials must have superior performance such as high temperature resistance, corrosion resistance and wear resistance to be used in a relatively harsh environment. It is difficult for traditional materials to meet the requirements. Developing and effectively utilizing high-performance materials has become an inevitable trend in the development of material science. However, the ceramic material in the prior art has a low coefficient of thermal expansion, resulting in a low heat dissipation capacity, which is liable to cause a fire safety implication, and does not meet the requirements of the chip-type and miniaturized sensor electronic sensor ceramic material in the existing market. 
     SUMMARY 
     The present disclosure aims to provide a pressure sensor ceramic material and a preparation method thereof. 
     The present disclosure provides the following technical solution: the pressure sensor ceramic material, by weight component, comprising: 
     45 parts to 50 parts of nano ceramic particles with a molecular formula CaCu 3-x M x Ti 4- ySc y O 12 , wherein: 0&lt;x≤1, 0.2≤y≤0.8, and an element M is Ni, Zr, Co, Sr; 
     20 parts to 25 parts of glass-phase nano-oxide particles with a molecular formula B 2 O 3 , wherein: an element A is Er, Fe, Cr or Bi; 
     AlN: 15 parts to 20 parts; 
     BeO: 8 parts to 12 parts; 
     polymethylformamide: 20 parts to 30 parts; 
     polycrystalline diamond powder: 10 parts to 15 parts; 
     microfiltration membrane polymer: 55 parts to 65 parts; and 
     dimethylformamide 20 parts to 25 parts. 
     Further, a preparation method of CaCu 3-x M x Ti 4- ySc y O 12  nano ceramic particles comprises following steps: 
     S1: dissolving calcium inorganic saline compound, copper inorganic saline compound and M element inorganic saline compound in ethanol at a molar ratio of 1:3-x: x to form first mixed precursor solution; 
     S2: dissolving silane coupling agent and scandium inorganic saline compound in acetylacetone at a molar ratio of 4-y:y to form second mixed precursor solution; 
     S3: stirring the first mixed precursor solution obtained in the S1 and the second mixed precursor solution obtained in the S2 at a temperature of 95° C. to 105° C. and at a revolution speed of 200 rpm to 300 rpm for 15 minutes, and adding ethanol solution dropwise during the stirring to form CaCu 3-x M x Ti 4- ySc y O 12  nanometer precursor gel; 
     S4: drying the CaCu 3-x M x Ti 4- ySc y O 12  nanometer precursor obtained in the S3 in a nitrogen gas atmosphere at a temperature of 150° C. to 160° C. for 2 hours to 2.5 hours, and grounding by a planetary ball mill to obtain CaCu 3-x M x Ti 4- ySc y O 12 nanometer precursor powder; and 
     S5: calcining the CaCu 3-x M x Ti 4- ySc y O 12  nanometer precursor powder at a temperature of 950° C. to 1150° C. for 1 hour to 1.5 hours, and preventing CaCu 3-x M x Ti 4- ySc y O 12  crystals from growing to obtain the CaCu 3-x M x Ti 4- ySc y O 12  nano ceramic particles. 
     Further, titanate coupling agent is one or more of tetraisopropyl di-titanate, isopropyl titanate, diisopropyl titanate or tetrabutyl orthotitanate. 
     Further, the copper inorganic saline compound is Cu(NO 3 )2.3H 2 O, Cu(CH 3 COO) 2 .H 2 O, CuCl 2 .2H 2 O or CuSO 4 .5H 2 O; the calcium inorganic saline compound is Ca(NO 3 )2.4H 2 O, Ca(CH 3 COO)2.H 2 O, CaSO 4 .2H 2 O or CaCl 2 .6H 2 O. 
     Further, hydrates of the M element inorganic saline compound are Ni(NO 3 ) 2 .6H 2 O, Ni(CH 3 COO) 2 .4H 2 O, NiSO 4 .6H 2 O, NiCl 2 .6H 2 O, Zr(NO 3 ) 3 .5H 2 O, Zr(SO 4 ) 2 .4H 2 O, ZrOCl 2 .8H 2 O, Co(NO 3 ) 2 .6H 2 O, Co(CH 3 COO) 2 .4H 2 O, Co(SO 4 ) 2 .7H 2 O, CoCl 2 .6H 2 O, Sr(CH 3 COO) 2 .2H 2 O or SrCl 2 .6H 2 O; and the scandium inorganic salts are ScCl 3 .6H 2 O, Sc 2 (SO 4 ) 3 .8H 2 O, Sc(CH 3 COO) 3 .5H 2 O, Sc(NO 3 ) 3 .H 2 O. 
     Further, a volume fraction of the ethanol in the ethanol solution added dropwise in the step S3 is 20% to 40%. 
     Further, the polycrystalline diamond powder has a particle size of 15 μm to 25 μm. 
     Further, a preparation method of the pressure sensor ceramic material, comprising the following steps: 
     M1: dissolving the polycrystalline diamond powder in concentrated NaOH solution with a concentration of 10M to 12M, after boiling at a temperature of 100° C. to 110° C., washing with distilled water three times, then immersing in HCl with a concentration of 2M to 5M, shaking under ultrasonic wave for 20 minutes to 30 minutes to obtain pretreated polycrystalline diamond powder; 
     M2: mixing AlN of the weight component and BeO of the weight component with polymethylformamide of the weight component, and stirring at a temperature of 60° C. to 70° C. and at a revolution speed of 180 rpm to 230 rpm for 10 minutes to 15 minutes; 
     M3: placing mixture obtained in the M2 and the pretreated polycrystalline diamond powder obtained in the M1 in a vacuum, vacuuming in an inert atmosphere at 10 MPa to 15 MPa, and heating at a heating rate of 20° C./min to a temperature of 350° C. to 400° C. and holding for 1.5 hours, continuing heating at the heating rate of 20° C./min to a temperature of 950° C. to 1000° C. and holding for 2 hours to 2.5 hours to obtain diamond powder coated with a sub-micron layer doped the AlN and the BeO, and the sub-micron layer is 10 μm to 20 μm; 
     M4: mixing nano ceramic particles with the molecular formula CaCu 3-x M x Ti 4- ySc y O 12  of the weight component, B 2 O 3  glass-phase nano-oxide particles of the weight component, and one-third of dimethylformamide of the weight component, stirring at a temperature of 50° C. to 70° C. and at a revolution speed of 150 rpm to 200 rpm for 30 minutes to 45 minutes, standing obtained mixture at a room temperature for 10 minutes, then centrifuging at a revolution speed of 3000 rpm to 4000 rpm for 5 minutes to 10 minutes, washing the obtained precipitate in the ethanol for 3 times, and then washing in the distilled water for 3 times to obtain B 2 O 3  glass-phase nano-oxide particles modified CaCu 3-x M x Ti 4- ySc y O 12  gradient nanoparticles; and 
     M5: mixing the B 2 O 3  glass-phase nano-oxide particles modified CaCu 3-x M x Ti 4- ySc y O 12  gradient nanoparticle obtained in the M4 and remaining two-thirds of dimethylformamide of the weight component uniformly, and then mixing with microfiltration membrane polymer of the weight component and diamond powder coated with a sub-micron layer doped the AlN and the BeO obtained in the M3, stirring at a temperature of 55° C. to 75° C. and at a revolution speed of 250 rpm to 300 rpm for 30 minutes to 45 minutes, then drying under nitrogen gas flow at a temperature of 70° C. to 80° C. to obtain the pressure sensor ceramic material. 
     Further, the inert atmosphere used for vacuuming in the M3 is an argon atmosphere, and a flow rate is 160 ml/min to 200 ml/min 
     The beneficial effects of the present disclosure are: 
     1. The diamond powder coated with 10 μm to 20 μm of the sub-micron layer doped the AlN and the BeO can be prepared by using polycrystalline diamond powder and AlN, BeO after polymethylformamide treatment, in a vacuum inert atmosphere at high temperature. Polycrystalline diamond has good mechanical strength, and the bonding strength of the final ceramic composite can be enhanced by adding AlN and BeO. In the coating process, the BeO can make the Be2+ ion as the acceptor diffused to form a grain boundary barrier and improve the height of the grain boundary barrier, so as to affect the electrical property and reduce the defect of uniform and isotropic crystal structure caused by gradient modification of CaCu3-xMxTi4-yScyO12 by B2O3 glass-phase nano-oxide, reduces the stress concentration of the resulting pressure sensor ceramic material against impact, further enhances the mechanical properties of the pressure sensor ceramic material, and avoids the defect that the cross-section bonding degree decreases due to the grain boundary movement. Meanwhile, AlN can be stabilized up to 2200° C., and the strength at the room temperature is high and decreases slowly with the increase of the room temperature. The pressure sensor ceramic material has good thermal conductivity, small thermal expansion coefficient, and is a good heat-resistant impact material. And the pressure sensor ceramic material has strong resistance to molten metal erosion, and it is a good electrical insulator with excellent dielectric properties. By means of AlN and BeO coated polycrystalline diamond, the insulation property of the pressure sensor ceramic material is further enhanced and the thermal expansion coefficient is reduced, so that the final pressure sensor ceramic material has good insulation property and heat dissipation property. 
     2. In the present disclosure, nano ceramic particles with a molecular formula CaCu 3-x M x Ti 4- ySc y O 12  are prepared by self-manufacturing, and Cu is substituted with Ni, Zr, Co, Sr, and mixed with calcium inorganic saline compound, mixture of copper inorganic saline compound and M metal inorganic saline compound, and M element mixed precursor solution in the preparation process, so as to obtain a compact microstructure and reduce the porosity of the nanoparticle, furthermore, to change the spatial structure of the CaCu 3 Ti 4 O 12 , and improve the dielectric constant and dielectric loss of the final CaCu 3-x M x Ti 4- ySc y O 12  nano ceramic particles by increasing the anisotropic field. At the same time, the doping and substitution of Ti by Sc element reduces the vacancy of Ti in space, thus making the prepared CaCu 3-x M x Ti 4- ySc y O 12  geometric space structure more orderly, and ensuring the potential gradient of CaCu 3-x M x Ti 4-y Sc y O 12  and reducing dielectric loss and leakage current of CaCu 3-x M x Ti 4- ySc y O 12 . 
     3. Adding glass-phase nano-oxide particles with the molecular formula B2O3 and encapsulating the nano ceramic particles with the formula CaCu3-xMxTi4-yScyO12, to improve the melting enthalpy of the CaCu3-xMxTi4-yScyO12 nano ceramic particles, and the modification is gradient modification, with nano ceramic particles close to the inner core CaCu3-xMxTi4-ySc y O 12 , the content of the outer shell B 2 O 3  glass phase nanoparticles is low; with the nano ceramic particles away from the inner core CaCu 3-x M x Ti 4- ySc y O 12 , the shell B 2 O 3  glass phase nanoparticles gradually increases. Furthermore, the dielectric constant of the capacitor varistor sensor is not reduced while the insulation property is improved, so that the pressure sensor ceramic material obtained has high dielectric constant, low dielectric loss and high insulation property. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The technical solution in the embodiment of the present disclosure will be clearly and completely described in connection with the embodiment of the present disclosure. It is obvious that the described embodiment is only part of the embodiment of the present disclosure and not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present disclosure. 
     Embodiment 1 
     A pressure sensor ceramic material is provided in the embodiment, by weight component, comprising: 
     nano ceramic particles with a molecular formula CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12 : 45 parts; 
     glass-phase nano-oxide particles with a molecular formula Er 2 O 3 : 20 parts; 
     AlN: 15 parts; 
     BeO: 8 parts; 
     polymethylformamide: 20 parts; 
     polycrystalline diamond powder with a particle size of 15 μm: 10 parts; 
     polyvinylidene fluoride: 55 parts; and 
     dimethylformamide 20 parts. 
     Wherein: a preparation method of CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12  nano ceramic particles comprises following steps: 
     S1: dissolving Ca(CH 3 COO) 2 .H 2 , Cu(CH 3 COO) 2 .H 2 O, Ni(CH 3 COO) 2 .4H 2 O and Co(CH 3 COO) 2 .4H 2 O in ethanol at a molar ratio of 1:2:0.6:0.4 to form first mixed precursor solution; 
     S2: dissolving tetrabutyl orthotitanate and Sc(CH 3 COO) 3 .5H 2 O in acetylacetone at a molar ratio of 3.8:0.2 to form second mixed precursor solution; 
     S3: stirring the first mixed precursor solution obtained in the S1 and the second mixed precursor solution obtained in the S2 at a temperature of 95° C. and at a revolution speed of 200 rpm for 15 minutes, and adding ethanol solution with a volume fraction of 20% dropwise during the stirring to form CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12  nanometer precursor gel; 
     S4: drying the CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12  nanometer precursor obtained in the S3 in a nitrogen gas atmosphere at a temperature of 150° C. for 2 hours, and grounding by a planetary ball mill to obtain CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12  nanometer precursor powder; and 
     S5: calcining the CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12  nanometer precursor powder at a temperature of 950° C. for an hour, and preventing CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12  crystals from growing to obtain the CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12  nano ceramic particles. 
     A preparation method of the pressure sensor ceramic material is provided in the embodiment, comprising the following steps: 
     M1: dissolving 10 parts of the polycrystalline diamond powder with a particle size of 15 μm in concentrated NaOH solution with a concentration of 10M, after boiling at a temperature of 100° C., washing with distilled water three times, then immersing in HCl with a concentration of 2M, shaking under ultrasonic wave for 20 minutes to obtain pretreated polycrystalline diamond powder; 
     M2: mixing 15 parts of the AlN and 8 parts of the BeO with 20 parts of the polymethylformamide, and stirring at a temperature of 61° C. and at a revolution speed of 180 rpm for 10 minutes; 
     M3: placing mixture obtained in the M2 and the pretreated polycrystalline diamond powder obtained in the M1 in a vacuum, vacuuming in an argon atmosphere with a flow rate of 160 ml/min at 10 MPa, and heating at a heating rate of 20° C./min to a temperature of 350° C. and holding for 1.5 hours, continuing heating at the heating rate of 20° C./min to a temperature of 950° C. and holding for 2 hours to obtain diamond powder coated with a sub-micron layer doped the AlN and the BeO, and the sub-micron layer is 10 μm; 
     M4: mixing the 45 parts of nano ceramic particles with the molecular formula CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12 , the Er 2 O 3  glass-phase nano-oxide particles of the weight component, and 6.67 parts of the dimethylformamide, stirring at a temperature of 50° C. and at a revolution speed of 150 rpm for 30 minutes, standing obtained mixture at a room temperature for 10 minutes, then centrifuging at a revolution speed of 3000 rpm for 5 minutes, washing the obtained precipitate in the ethanol for 3 times, and then washing in the distilled water for 3 times to obtain Er 2 O 3  glass-phase nano-oxide particles modified CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12  gradient nanoparticles; and 
     M5: mixing the Er 2 O 3  glass-phase nano-oxide particles modified CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12  gradient nanoparticle obtained in the M4 and remaining 13.33 parts of the dimethylformamide uniformly, and then mixing with the 55 parts of the polyvinylidene fluoride and the diamond powder coated with the sub-micron layer doped the AlN and the BeO obtained in the M3, stirring at a temperature of 55° C. and at a revolution speed of 250 rpm for 30 minutes, then drying under nitrogen gas flow at a temperature of 70° C. to obtain the pressure sensor ceramic material. 
     Embodiment 2 
     A pressure sensor ceramic material is provided in the embodiment, by weight component, comprising: 
     nano ceramic particles with a molecular formula CaCu 2.5 Zr 0.5 Ti 3.5 Sc 0.5 O 12 : 50 parts; 
     glass-phase nano-oxide particles with a molecular formula Bi 2 O 3 : 25 parts; 
     AlN: 20 parts; 
     BeO: 12 parts; 
     polymethylformamide 30 parts; 
     polycrystalline diamond powder with a particle size of 20 μm: 15 parts; 
     polysulfonated phenyl ether sulfone: 65 parts; and 
     dimethylformamide 25 parts. 
     Wherein: a preparation method of CaCu 2.5 Zr 0.5 Ti 3.5 Sc 0.5 O 12  nano ceramic particles comprises following steps: 
     S1: dissolving CaSO 4 .2H 2 O, CuSO 4 .5H 2 O, and Zr(SO 4 ) 2 .4H 2 O in ethanol at a molar ratio of 1:2.5:0.5 to form first mixed precursor solution; 
     S2: dissolving tetraisopropyl di-titanate and Sc 2 (SO 4 ) 3 .8H 2 O in acetylacetone at a molar ratio of 7:1 to form second mixed precursor solution; 
     S3: stirring the first mixed precursor solution obtained in the S1 and the second mixed precursor solution obtained in the S2 at a temperature of 105° C. and at a revolution speed of 300 rpm for 15 minutes, and adding ethanol solution with a volume fraction of 40% dropwise during the stirring to form CaCu 2.5 Zr 0.5 Ti 3.5 Sc 0.5 O 12  nanometer precursor gel; 
     S4: drying the CaCu 2.5 Zr 0.5 Ti 3.5 Sc 0.5 O 12  nanometer precursor obtained in the S3 in a nitrogen gas atmosphere at a temperature of 160° C. for 2.5 hours, and grounding by a planetary ball mill to obtain CaCu 2.5 Zr 0.5 Ti 3.5 Sc 0.5 O 12  nanometer precursor powder; and 
     S5: calcining the CaCu 2.5 Zr 0.5 Ti 3.5 Sc 0.5 O 12  nanometer precursor powder at a temperature of 1150° C. for 1.5 hours, and preventing CaCu 2.5 Zr 0.5 Ti 3.5 Sc 0.5 O 12  crystals from growing to obtain the CaCu 2.5 Zr 0.5 Ti 3.5 Sc 0.5 O 12  nano ceramic particles. 
     A preparation method of the pressure sensor ceramic material is provided in the embodiment, comprising the following steps: 
     M1: dissolving 15 parts of the polycrystalline diamond powder with a particle size of 20 μm in concentrated NaOH solution with a concentration of 12M, after boiling at a temperature of 110° C., washing with distilled water three times, then immersing in HCl with a concentration of 5M, shaking under ultrasonic wave for 30 minutes to obtain pretreated polycrystalline diamond powder; 
     M2: mixing 20 parts of the AlN and 12 parts of the BeO with 30 parts of the polymethylformamide, and stirring at a temperature of 70° C. and at a revolution speed of 230 rpm for 15 minutes; 
     M3: placing mixture obtained in the M2 and the pretreated polycrystalline diamond powder obtained in the M1 in a vacuum, vacuuming in an argon atmosphere with a flow rate of 180 ml/min at 15 MPa, and heating at a heating rate of 20° C./min to a temperature of 400° C. and holding for 1.5 hours, continuing heating at the heating rate of 20° C./min to a temperature of 1000° C. and holding for 2.5 hours to obtain diamond powder coated with a sub-micron layer doped the AlN and the BeO, and the sub-micron layer is 15 μm; 
     M4: mixing the 50 parts of nano ceramic particles with the molecular formula CaCu 2.5 Zr 0.5 Ti 3.5 Sc 0.5 O 12 , 25 parts of the Bi 2 O 3  glass-phase nano-oxide particles, and 11.67 parts of the dimethylformamide, stirring at a temperature of 70° C. and at a revolution speed of 200 rpm for 45 minutes, standing obtained mixture at a room temperature for 10 minutes, then centrifuging at a revolution speed of 4000 rpm for 10 minutes, washing the obtained precipitate in the ethanol for 3 times, and then washing in the distilled water for 3 times to obtain Bi 2 O 3  glass-phase nano-oxide particles modified CaCu 2.5 Zr 0.5 Ti 3.5 Sc 0.5 O 12  gradient nanoparticles; and 
     M5: mixing the Bi 2 O 3  glass-phase nano-oxide particles modified CaCu 2.5 Zr 0.5 Ti 3.5 Sc 0.5 O 12  gradient nanoparticle obtained in the M4 and remaining 13.33 parts of the dimethylformamide uniformly, and then mixing with the 65 parts of the polysulfonated phenyl ether sulfone and the diamond powder coated with the sub-micron layer doped the AlN and the BeO obtained in the M3, stirring at a temperature of 75° C. and at a revolution speed of 300 rpm for 45 minutes, then drying under nitrogen gas flow at a temperature of 80° C. to obtain the pressure sensor ceramic material. 
     Embodiment 3 
     A pressure sensor ceramic material is provided in the embodiment, by weight component, comprising: 
     nano ceramic particles with a molecular formula CaCu 2.9 Sr 0.1 Ti 3.2 Sc 0.8 O 12 : 47.5 parts; 
     glass-phase nano-oxide particles with a molecular formula Cr 2 O 3 : 22.5 parts; 
     AlN: 17.5 parts; 
     BeO: 10 parts; 
     polymethylformamide 25 parts; 
     polycrystalline diamond powder with a particle size of 25 μm: 12.5 parts; 
     polyphenylene sulfide: 25 parts; 
     polytetrafluoroethylene: 25 parts; and 
     dimethylformamide 22.5 parts. 
     Wherein: a preparation method of CaCu 2.9 Sr 0.1 Ti 3.2 Sc 0.8 O 12  nano ceramic particles comprises following steps: 
     S1: dissolving CaCl 2 .6H 2 O, CuCl 2 .2H 2 O, and SrCl 2 .6H 2 O in ethanol at a molar ratio of 1:2.9:0.1 to form first mixed precursor solution; 
     S2: dissolving diisopropyl titanate and ScCl 3 .6H 2 O in acetylacetone at a molar ratio of 4:1 to form second mixed precursor solution; 
     S3: stirring the first mixed precursor solution obtained in the S1 and the second mixed precursor solution obtained in the S2 at a temperature of 100° C. and at a revolution speed of 250 rpm for 15 minutes, and adding ethanol solution dropwise during the stirring to form CaCu 2.9 Sr 0.1 Ti 3.2 Sc 0.8 O 12  nanometer precursor gel; 
     S4: drying the CaCu 2.9 Sr 0.1 Ti 3.2 Sc 0.8 O 12 nanometer precursor obtained in the S3 in a nitrogen gas atmosphere at a temperature of 155° C. for 2.25 hours, and grounding by a planetary ball mill to obtain CaCu 2.9 Sr 0.1 Ti 3.2 Sc 0.8 O 12  nanometer precursor powder; and 
     S5: calcining the CaCu 2.9 Sr 0.1 Ti 3.2 Sc 0.8 O 12  nanometer precursor powder at a temperature of 1000° C. for 1.25 hours, and preventing CaCu 2.9 Sr 0.1 Ti 3.2 Sc 0.8 O 12  crystals from growing to obtain the CaCu 2.9 Sr 0.1 Ti 3.2 Sc 0.8 O 12  nano ceramic particles. 
     A preparation method of the pressure sensor ceramic material is provided in the embodiment, comprising the following steps: 
     M1: dissolving 12.5 parts of the polycrystalline diamond powder with a particle size of 25 μm in concentrated NaOH solution with a concentration of 11M, after boiling at a temperature of 105° C., washing with distilled water three times, then immersing in HCl with a concentration of 3.5M, shaking under ultrasonic wave for 25 minutes to obtain pretreated polycrystalline diamond powder; 
     M2: mixing 17.5 parts of the AlN and 10 parts of the BeO with polymethylformamide, of the weight component and stirring at a temperature of 65° C. and at a revolution speed of 205 rpm for 12 minutes; 
     M3: placing mixture obtained in the M2 and the pretreated polycrystalline diamond powder obtained in the M1 in a vacuum, vacuuming in an argon atmosphere with a flow rate of 200 ml/min at 12.5 MPa, and heating at a heating rate of 20° C./min to a temperature of 375° C. and holding for 1.5 hours, continuing heating at the heating rate of 20° C./min to a temperature of 980° C. and holding for 2.25 hours to obtain diamond powder coated with a sub-micron layer doped the AlN and the BeO, and the sub-micron layer is 20 μm; 
     M4: mixing the 47.5 parts of nano ceramic particles with the molecular formula CaCu 2.9 Sr 0.1 Ti 3.2 Sc 0.8 O 12 , 22.5 parts of the Cr 2 O 3  glass-phase nano-oxide particles, and 7.5 parts of the dimethylformamide, stirring at a temperature of 65° C. and at a revolution speed of 175 rpm for 38 minutes, standing obtained mixture at a room temperature for 10 minutes, then centrifuging at a revolution speed of 4000 rpm for 10 minutes, washing the obtained precipitate in the ethanol for 3 times, and then washing in the distilled water for times to obtain Cr 2 O 3  glass-phase nano-oxide particles modified CaCu 2.9 Sr 0.1 Ti 3.2 Sc 0.8 O 12  gradient nanoparticles; and 
     M5: mixing the Cr 2 O 3  glass-phase nano-oxide particles modified CaCu 2.9 Sr 0.1 Ti 3.2 Sc 0.8 O 12  gradient nanoparticle obtained in the M4 and remaining 15 parts of the dimethylformamide uniformly, and then mixing with the 25 parts of the polyphenylene sulfide, 25 parts of the polytetrafluoroethylene and the diamond powder coated with the sub-micron layer doped the AlN and the BeO obtained in the M3, stirring at a temperature of 65° C. and at a revolution speed of 275 rpm for 37 minutes, then drying under nitrogen gas flow at a temperature of 75° C. to obtain the pressure sensor ceramic material. 
     Comparative Embodiment 1 
     The present comparative embodiment differs from Embodiment 1 in: AlN and BeO are not used and by weight component, comprising: 
     nano ceramic particles with a molecular formula CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12 : 45 parts; 
     glass-phase nano-oxide particles with a molecular formula Er 2 O 3 : 20 parts; 
     polymethylformamide: 20 parts; 
     polycrystalline diamond powder with a particle size of 15 μm: 10 parts; 
     polyvinylidene fluoride: 55 parts; and 
     dimethylformamide 20 parts. 
     Further, the final production steps comprises the following steps: 
     M1: dissolving 10 parts of the polycrystalline diamond powder with a particle size of 15 μm in concentrated NaOH solution with a concentration of 10M, after boiling at a temperature of 100° C., washing with distilled water three times, then immersing in HCl with a concentration of 2M, shaking under ultrasonic wave for 20 minutes to obtain pretreated polycrystalline diamond powder; 
     M2: mixing the mixture obtained in the M1 with 20 parts of the polymethylformamide, and stirring at a temperature of 61° C. and at a revolution speed of 180 rpm for 10 minutes; 
     M3: placing mixture obtained in the M2 and the pretreated polycrystalline diamond powder obtained in the M1 in a vacuum, vacuuming in an argon atmosphere with a flow rate of 160 ml/min at 10 MPa, and heating at a heating rate of 20° C./min to a temperature of 350° C. and holding for 1.5 hours, continuing heating at the heating rate of 20° C./min to a temperature of 950° C. and holding for 2 hours to obtain diamond powder coated with a sub-micron layer doped the AlN and the BeO, and the sub-micron layer is 10 μm; 
     M4: mixing the 45 parts of nano ceramic particles with the molecular formula CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12 , the Er 2 O 3  glass-phase nano-oxide particles of the weight component, and 6.67 parts of the dimethylformamide, stirring at a temperature of 50° C. and at a revolution speed of 150 rpm for 30 minutes, standing obtained mixture at a room temperature for 10 minutes, then centrifuging at a revolution speed of 3000 rpm for 5 minutes, washing the obtained precipitate in the ethanol for 3 times, and then washing in the distilled water for 3 times to obtain Er 2 O 3  glass-phase nano-oxide particles modified CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12  gradient nanoparticles; and 
     M5: mixing the Er 2 O 3  glass-phase nano-oxide particles modified CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12  gradient nanoparticle obtained in the M4 and remaining 13.33 parts of the dimethylformamide uniformly, and then mixing with the 55 parts of the polyvinylidene fluoride and the diamond powder coated with the sub-micron layer doped the AlN and the BeO obtained in the M3, stirring at a temperature of 55° C. and at a revolution speed of 250 rpm for 30 minutes, then drying under nitrogen gas flow at a temperature of 70° C. to obtain the pressure sensor ceramic material. 
     Wherein, the preparation method of nano ceramic particles with the formula CaCu2(Ni0.6Co0.4)Ti3.8Sc0.2O12 is carried out as described in Embodiment 1. 
     Comparative Embodiment 2 
     The present comparative embodiment differs from Embodiment 1 in that the composition of Er 2 O 3  glass-phase nano-oxide particles is not used and by weight component, comprising: 
     nano ceramic particles with a molecular formula CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12 : 45 parts; 
     AlN: 15 parts; 
     BeO: 8 parts; 
     polymethylformamide: 20 parts; 
     polycrystalline diamond powder with a particle size of 15 μm: 10 parts; 
     polyvinylidene fluoride: 55 parts; and 
     dimethylformamide 20 parts. 
     Further, the final production steps comprises the following steps: 
     M1: dissolving 10 parts of the polycrystalline diamond powder with a particle size of 15 μm in concentrated NaOH solution with a concentration of 10M, after boiling at a temperature of 100° C., washing with distilled water three times, then immersing in HCl with a concentration of 2M, shaking under ultrasonic wave for 20 minutes to obtain pretreated polycrystalline diamond powder; 
     M2: mixing 15 parts of the AlN and 8 parts of the BeO with 20 parts of the polymethylformamide, and stirring at a temperature of 61° C. and at a revolution speed of 180 rpm for 10 minutes; 
     M3: placing mixture obtained in the M2 and the pretreated polycrystalline diamond powder obtained in the M1 in a vacuum, vacuuming in an argon atmosphere with a flow rate of 160 ml/min at 10 MPa, and heating at a heating rate of 20° C./min to a temperature of 350° C. and holding for 1.5 hours, continuing heating at the heating rate of 20° C./min to a temperature of 950° C. and holding for 2 hours to obtain diamond powder coated with a sub-micron layer doped the AlN and the BeO, and the sub-micron layer is 10 μm; 
     M4: mixing the 45 parts of the CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12  nano ceramic particles with 20 parts of the dimethylformamide uniformly, and then mixing with the 55 parts of the polyvinylidene fluoride and the diamond powder coated with the sub-micron layer doped the AlN and the BeO obtained in the M3, stirring at a temperature of 55° C. and at a revolution speed of 250 rpm for 30 minutes, then drying under nitrogen gas flow at a temperature of 70° C. to obtain the pressure sensor ceramic material. 
     Wherein, the preparation method of nano ceramic particles with the formula CaCu 2 (Ni0. 6 Co 0.4 )Ti 3 .8Sc 0.2 O 12  is carried out as described in Embodiment 1. 
     Comparative Embodiment 3 
     the present comparative embodiment differs from Embodiment 1 in that CaCu 3 Ti4O12 nano ceramic particles are used instead of the self-made CaCu 2.5 Ni 0.5 Ti 4 O 12  nano ceramic particles and by weight component, comprising: 
     CaCu 3 Ti 4 O 12  nano ceramic particles: 45 parts; 
     glass-phase nano-oxide particles with a molecular formula Er 2 O 3 : 20 parts; 
     AlN: 15 parts; 
     BeO: 8 parts; 
     polymethylformamide: 20 parts; 
     polycrystalline diamond powder with a particle size of 15 μm: 10 parts; 
     polyvinylidene fluoride: 55 parts; and 
     dimethylformamide 20 parts. 
     M1: dissolving 10 parts of the polycrystalline diamond powder with a particle size of 15 μm in concentrated NaOH solution with a concentration of 10M, after boiling at a temperature of 100° C., washing with distilled water three times, then immersing in HCl with a concentration of 2M, shaking under ultrasonic wave for 20 minutes to obtain pretreated polycrystalline diamond powder; 
     M2: mixing 15 parts of the AlN and 8 parts of the BeO with 20 parts of the polymethylformamide, and stirring at a temperature of 61° C. and at a revolution speed of 180 rpm for 10 minutes; 
     M3: placing mixture obtained in the M2 and the pretreated polycrystalline diamond powder obtained in the M1 in a vacuum, vacuuming in an argon atmosphere with a flow rate of 160 ml/min at 10 MPa, and heating at a heating rate of 20° C./min to a temperature of 350° C. and holding for 1.5 hours, continuing heating at the heating rate of 20° C./min to a temperature of 950° C. and holding for 2 hours to obtain diamond powder coated with a sub-micron layer doped the AlN and the BeO, and the sub-micron layer is 10 μm; 
     M4: mixing the 45 parts of nano ceramic particles with the molecular formula CaCu 2 (Ni 0.6 Co 0.4 )Ti 3.8 Sc 0.2 O 12 , the Er 2 O 3  glass-phase nano-oxide particles of the weight component, and 6.67 parts of the dimethylformamide, stirring at a temperature of 50° C. and at a revolution speed of 150 rpm for 30 minutes, standing obtained mixture at a room temperature for 10 minutes, then centrifuging at a revolution speed of 3000 rpm for 5 minutes, washing the obtained precipitate in the ethanol for 3 times, and then washing in the distilled water for 3 times to obtain Er 2 O 3  glass-phase nano-oxide particles modified CaCu 3 Ti 4 O 12  gradient nanoparticles; and 
     M5: mixing the Er 2 O 3  glass-phase nano-oxide particles modified CaCu 3 Ti 4 O 12  gradient nanoparticle obtained in the M4 and remaining 13.33 parts of the dimethylformamide uniformly, and then mixing with the 55 parts of the polyvinylidene fluoride and the diamond powder coated with the sub-micron layer doped the AlN and the BeO obtained in the M3, stirring at a temperature of 55° C. and at a revolution speed of 250 rpm for 30 minutes, then drying under nitrogen gas flow at a temperature of 70° C. to obtain the pressure sensor ceramic material. 
     Test Embodiment 
     The mechanical strength, resistivity (representing insulation), porosity, dielectric constant, dielectric loss, leakage current, and coefficient of thermal expansion of the pressure sensor ceramic material of Embodiment 1 to Embodiment 3 and Comparative Embodiment 1 to Embodiment 3 are tested, and the results are shown in Table 1. 
     Although the present disclosure has been described with reference to the preferred embodiments, various modifications can be made to it without departing from the scope of the present disclosure and the components and parameters therein can be replaced with equivalents. Specifically, as long as there is no conflict of technical solutions, the various technical features mentioned in the various embodiments can be combined in any manner. The present disclosure is not limited to the specific embodiments disclosed herein, but comprises all technical solutions falling within the scope of the claims. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                   
                 Comparative 
                 Comparative 
                 Comparative 
               
               
                   
                 Embodi- 
                 Embodi- 
                 Embodi- 
                 Embodi- 
                 Embodi- 
                 Embodi- 
               
               
                   
                 ment 
                 ment 
                 ment 
                 ment 
                 ment 
                 ment 
               
               
                   
                 1 
                 2 
                 3 
                 1 
                 2 
                 3 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Mechanical 
                 36  
                 38  
                 45  
                 24  
                 21  
                 19  
               
               
                 strength 
                 Shao A 
                 Shao A 
                 Shao A 
                 Shao A 
                 Shao A 
                 Shao A 
               
               
                 Resistivity 
                 126 ×  
                 137 ×  
                 142 ×  
                 306 ×  
                 573 ×  
                 231 ×  
               
               
                 (Ω · m) 
                 10 −7   
                 10 −7   
                 10 −7   
                 10 −8   
                 10 −7   
                 10 −8   
               
               
                 Porosity 
                 32.15%   
                 34.11%   
                 37.02%   
                 10.10%   
                 9.64%  
                 6.98%  
               
               
                 Dielectric 
                 1406 
                 1432 
                 1542 
                 336 
                 167 
                 252 
               
               
                 Constant 
                   
                   
                   
                   
                   
                   
               
               
                 Dielectric 
                 0.1397% 
                 0.1307% 
                 0.1125% 
                 0.3268% 
                 0.3744% 
                 0.5026% 
               
               
                 Loss 
                   
                   
                   
                   
                   
                   
               
               
                 Leakage 
                 153 μA 
                 147 μA 
                 142 μA 
                 265 μA 
                 278 μA 
                 302 μA 
               
               
                 Current 
                   
                   
                   
                   
                   
                   
               
               
                 Coefficient 
                 8.67 ×  
                 8.35 ×  
                 7.6 ×  
                 21.87 ×  
                 18.23 ×  
                 16.45 ×  
               
               
                 of Thermal 
                 10 −6 /K 
                 10 −6 /K 
                 10 −6 /K 
                 10 −6 /K 
                 10 −6 /K 
                 10 −6 /K 
               
               
                 Expansion