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High-performance zinc oxide composite ceramic voltage dependent resistor material and preparation method

A technology of varistors and composite ceramics, applied in the direction of varistors, varistor cores, etc., can solve the problems of changing varistors, reducing the surge absorption capacity of varistors, and destroying the micro-resistance structure of resistor sheets, etc. , to achieve the effect of increasing the potential gradient, realizing the miniaturization of the volume, and enriching the source

Inactive Publication Date: 2009-12-30
CHINA UNIV OF GEOSCIENCES (BEIJING)
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Problems solved by technology

However, the material formula of this system requires many types of trace additives, and bismuth oxide has strong volatility and high reactivity during the sintering process. The former changes the relative ratio of each component and thus changes the performance of the varistor. The latter It destroys the micro-resistance structure that composes the overall resistor, and at the same time, it is easy to generate an insulating spinel phase in the bismuth-based varistor material, thereby greatly reducing the surge absorption capacity of the varistor.

Method used

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  • High-performance zinc oxide composite ceramic voltage dependent resistor material and preparation method
  • High-performance zinc oxide composite ceramic voltage dependent resistor material and preparation method
  • High-performance zinc oxide composite ceramic voltage dependent resistor material and preparation method

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preparation example Construction

[0022] The preparation method comprises the following process steps and contents:

[0023] 1) Weigh raw materials according to the composition designed for the praseodymium-based zinc oxide varistor material, and add 0-10% (mass fraction) of dispersant and adhesive.

[0024] 2) Mix the claimed powder, dispersant and binder with zirconia balls and deionized water in a polyurethane ball mill tank, grind and mix them evenly on a high-energy ball mill.

[0025] 3) In a drying oven, the ground and mixed slurry is kept at a temperature of 40-250° C. for 12-96 hours and dried.

[0026] 4) Grinding the dried powder, and selecting a sieve with a suitable aperture for sieving.

[0027] 5) Dry press the ground powder in a mold with specified specifications and shapes.

[0028] 6) Sintering the praseodymium-based zinc oxide varistor ceramic green body according to a preset sintering system.

[0029] 7) Coating the praseodymium-based zinc oxide varistor ceramic sintered body with silver...

Embodiment 1

[0033] Commercially available analytically pure ZnO, Pr 6 o 11 , CoO, Cr 2 o 3 , Fe 2 o 3 Mixing is carried out in molar ratio, and the proportioning relationship is ZnO:Pr 6 o 11 :CoO:Cr 2 o 3 : Fe 2 o 3 =98:0.7:1.0:0.2:0.1, and add 5% (mass fraction) polyvinyl alcohol and 3% (mass fraction) Davon C, put into poly In the polyurethane ball mill tank, after ball milling on a high-energy ball mill for 48 hours, dry in the air and in a drying oven at 130°C for 72 hours, after grinding, dry press molding, sinter at 1300°C for 4 hours, and keep warm at 700°C 2 hours were made of silver electrodes. The resulting material is a typical two-phase structure, including a zinc oxide phase and a phase mainly composed of praseodymium oxide (see figure 1 ), the grain size is uniform (see figure 2 ). Zinc oxide composite ceramic varistor material made in this embodiment, 1mA / cm 2 When the potential gradient is 570V / mm, 1 / log(E 10mA / cm2 / E 1mA / cm2 ) when the nonlinear coeffic...

Embodiment 2

[0035] Commercially available analytically pure ZnO, Pr 6 o 11 , CoO, Cr 2 o 3 , Fe 2 o 3 、WO 3 Mixing is carried out in molar ratio, and the proportioning relationship is ZnO:Pr 6 o 11 :CoO:Cr 2 o 3 : Fe 2 o 3 : WO 3=97: 1.5: 1.0: 0.4: 0.05: 0.05, and add 1% (mass fraction) polyvinyl alcohol and 0.05% (mass fraction) Davon C, press 1: 4: 2 powder: zirconium ball: deionized water mass ratio Put it into a polyurethane ball mill tank, mill it on a high-energy ball mill for 48 hours, dry it in air and in a drying oven at 130°C for 24 hours, dry press it after grinding, sinter at 1300°C for 2 hours, and dry it at 700°C The electrodes were made of silver under incubation for 2 hours. The resulting material is a typical two-phase structure, including a zinc oxide phase and a phase mainly composed of praseodymium oxide (see image 3 ), the grain size is uniform (see Figure 4 ). Zinc oxide composite ceramic varistor material made in this embodiment, 1mA / cm 2 When the...

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Abstract

The invention relates to high-performance zinc oxide composite ceramic voltage dependent resistor material and a preparation method, which belongs to the technical field of electronic ceramic preparation and application. The ceramics takes zinc oxide as main phase, adopts praseodymium oxide as nonlinear initial phase, adopts a small amount of oxides of Co, Cr, Fe or W as potential gradient and nonlinear reinforcing agent, and comprises the following components by mole percent: 80 to 95 percent of ZnO, 0.01 to 15 percent of Pr6O, 0.01 to 10.0 percent of CoO, 0.01 to 8.0 percent of Cr2O3, 0.0 to 5.0 percent of Fe2O3 and 0.0 to 3.0 percent of WO3. The material preparation method comprises the following processing step in sequence: mixing->high-energy ball milling->drying->mixing and pelletizing->sifting->compression moulding forming->sintering->silver-layer coating. The voltage dependent resistor material has the advantages that the crystal grain is fine, the microscopic structure is uniform, the potential gradient E (the potential gradient value corresponding to 1 mA / cm<2> current density) is increased to 570 to 750 V / mm, the nonlinear coefficient alpha is 24 to 32, and the leakage current IL (the current density value corresponding 75 percent E) is 0.004 to 0.006 mA / cm<2>, and has excellent over-all electrical properties. The voltage dependent resistor material can be used for manufacturing the lightning arresters of ultra high voltage / extra high voltage power systems, and can realize the miniaturization of the lightning arrester. The invention can also be used for manufacturing cell phones and household appliance chip or multiplayer chip voltage dependent resistors.

Description

technical field [0001] The invention relates to a high-performance zinc oxide composite ceramic varistor material and a preparation method, belonging to the technical field of electronic ceramic preparation and application. Background technique [0002] Zinc oxide composite ceramic varistor material is a widely used electronic ceramic material to limit transient surge voltage. The material composition and microstructure of zinc oxide varistors have a great influence on material performance, and the requirements for material formulation and firing process are very strict; currently commercial zinc oxide varistors use bismuth-based (non-linear initial phase is bismuth oxide) varistors. Formulation of Resistive Materials (Gupta TK. Journal of the American Ceramic Society, 1990; 73: p1817). However, the material formula of this system requires many types of trace additives, and bismuth oxide has strong volatility and high reactivity during the sintering process. The former chan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/453C04B35/622H01C7/112
Inventor 彭志坚臧延旭王成彪付志强
Owner CHINA UNIV OF GEOSCIENCES (BEIJING)
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