CN101265083A - Rare earth nitrate doping zinc oxide pressure-sensitive ceramic material and preparation method thereof - Google Patents

Abstract

The invention relates to a rare earth nitrate-doped zinc oxide voltage-sensitive ceramic material and a production thereof, which belongs to the technology field of ceramic material production. The invention is characterized in that the zinc oxide voltage-sensitive ceramic material contains the following components in molar percentages: 94-98% of ZnO as major component, 0.1-1.0% of MnO2, 0.1-1.0% of Co2O3, 0.1-1.0% of Bi2O3, 0.1-1.0% of Cr2O3, 0.1-1.0% of Sb2O3 and 0.01-2.0% of rare earth nitrate, wherein the rare earth nitrate is at least one selected from nitrates of yttrium, praseodymium and strontium. By doping rare earth nitrate and controlling the doping concentration of rare earth nitrate, the invention ensures the uniformity of microscopic structure of the zinc oxide voltage-sensitive ceramic and improves the electrical property. The electric potential gradient of the voltage-sensitive ceramic is increased to 1000- 1300 V/mm, the nonlinear coefficient of the voltage-sensitive ceramic is 30-50, and the leakage current thereof is 2-20 MuA. The inventive voltage-sensitive ceramic can be used for the production of high-quality lightning protectors for extra-high voltage power systems.

Description

Zinc oxide pressure-sensitive ceramic material of rare earth nitrate doping and preparation method thereof

Technical field

The present invention relates to Zinc oxide pressure-sensitive ceramic material of a kind of rare earth nitrate doping and preparation method thereof, function of dominant stupalith manufacturing technology field.

Background technology

Since nineteen sixty-eight, PANASONIC was developed ZnO varistor; ZnO varistor is with premium propertiess such as it are cheap, easily manufactured, nonlinear factor is big, the time of response is fast, residual voltage is low, temperature conefficient of voltage is little, leakage current is little; be widely used in the power electronic system; as overvoltage protection device, surge absorber, varistor and thunder arrester etc., become the important kind in the present pressure-active element.

Doping proper amount of rare-earth oxide compound in the zinc oxide pressure-sensitive porcelain, rare earth oxide is pinned at the crystal boundary place, has obviously suppressed the growth of ZnO crystal grain, and the pressure sensitive voltage of pressure-sensitive porcelain is obviously improved.Doped with rare-earth oxide carries out modification to the ZnO voltage-sensitive ceramic, is a kind of important method that improves the ceramic dielectic potential gradient.Chinese patent CN1181502C has reported employing part nano zine oxide, and the pressure-sensitive porcelain of the adulterated ZnO of rare earth metal obtains having the voltage dependent resistor of excellent comprehensive performances behind 1160 ℃ of sintering 2h sintering, and its pressure sensitive voltage is 580V.Chinese patent CN1844044A passes through rare earth oxide Ce ₂O ₃, Gd ₂O ₃The single doping and codope, and adjust the rational proportion of doping content, at the ceramic dielectic that 1100-1180 ℃ of sintering obtains, potential gradient can be brought up to more than the 500V/mm.Chinese patent CN1801409A adds an amount of Y in the pressure-sensitive porcelain of ZnO ₂O ₃, obtaining potential gradient is about 2000V/mm, nonlinear factor is about 23 voltage dependent resistor.Aforesaid method generally adopts rare earth oxide to improve the potential gradient of zinc oxide pressure-sensitive porcelain, but because rare earth element Chang Gongsheng together, relatively disperse, how to exist with the ionic compound form, separation difficulty, extraction cost is bigger, so rare earth metal and oxide compound thereof cost an arm and a leg, is difficult to widespread use in actual industrial production.

Summary of the invention

One of purpose of the present invention provides that a kind of product performance are good, production cost is low, can be suitable for the rare earth nitrate doping Zinc oxide pressure-sensitive ceramic material of suitability for industrialized production.

Two of purpose of the present invention provides a kind of preparation method of Zinc oxide pressure-sensitive ceramic material of rare earth nitrate doping.

A kind of rare earth nitrate doping Zinc oxide pressure-sensitive ceramic material, it is characterized in that this material comprises following component by mole per-cent: ZnO 94-98% is a material of main part, MnO ₂, Co ₂O ₃, Bi ₂O ₃, Cr ₂O ₃, Sb ₂O ₃Respectively be 0.1-1.0%, rare earth nitrate is 0.01-2.0%, and wherein rare earth nitrate is a kind of in Yttrium trinitrate, praseodymium nitrate or the strontium nitrate.

A kind of preparation method who is used for above-mentioned rare earth nitrate doping Zinc oxide pressure-sensitive ceramic material is characterized in that this method comprises the steps:

1) prepares burden by above-mentioned rare earth nitrate doping Zinc oxide pressure-sensitive ceramic material component, adopt zirconia ball, polyethylene jar, dehydrated alcohol and distilled water are ball-milling medium, wet-milling 5h in the frequency conversion planetary ball mill, rotating speed 500rpm, zirconia ball: the batching powder: dehydrated alcohol: the mass ratio of distilled water is 100: 5: 18: 2; The slurry that ball milling is good becomes dry powder behind 70 ℃ of baking 24h, 700 ℃ of calcining 2h;

2) powder after the calcining adopts zirconia ball, polyethylene jar, the 1h that dry grinds, rotating speed 500rpm in the frequency conversion planetary ball mill; It is press forming behind 2% the PVA that dry grinding back powder adds 8% mass concentration;

3) base substrate of press forming is warming up to 500-600 ℃ with 5 ℃/min in resistance furnace, is incubated 2h, furnace cooling in the air atmosphere; Pretreated base substrate is warming up to 900-1200 ℃ with 5 ℃/min, is incubated 2h again in 900-1200 ℃ of air atmosphere, and furnace cooling promptly gets the rare earth nitrate doping Zinc oxide pressure-sensitive ceramic material.

Rare earth nitrate uses and can reduce production costs by a relatively large margin in function ceramics manufacturing field because preparation is easy, and price is relatively low.Adopt the rare earth nitrate doping zinc oxide pressure-sensitive ceramic, because rare earth nitrate forms solution in ball-milling medium, can be dispersed in more uniformly in the slurry after the drying, make microstructure evenly tiny behind the sintering, the electrical property of voltage-sensitive ceramic is improved.Utilize the ZnO pressure-sensitive ceramic material of formulation of the present invention, it obtains voltage-sensitive ceramic at 900-1100 ℃ of sintering, product has the excellent comprehensive performance, the density high porosity is low, homogeneous microstructure does not have obvious coacervate, potential gradient is brought up to 1000-1300V/mm, and nonlinear factor is 30-50, and leakage current is 2-20 μ A.The advantage that the present invention prepares high-pressure oxidation zinc voltage dependent resistor method is that technology is simple, low cost of manufacture.

Embodiment

After now embodiments of the invention being described in.

Embodiment 1

(1) weighing is ZnO 96.84% in molar ratio respectively, MnO ₂0.5%, Co ₂O ₃0.5%, Bi ₂O ₃0.5%, Cr ₂O ₃0.5%, Sb ₂O ₃1.0%, Y (NO ₃) ₃0.16%.

(2) adopt zirconia ball, polyethylene jar, dehydrated alcohol and distilled water are ball-milling medium, wet-milling 5h in the frequency conversion planetary ball mill, and rotating speed 500rpm, zirconia ball: the batching powder: dehydrated alcohol: the mass ratio of distilled water is 100: 5: 18: 2.

(3) slurry that ball milling is good becomes dry powder at 70 ℃ of baking 24h.

(4) 700 ℃ of calcining 2h.

(5) powder after the calcining adopts zirconia ball, polyethylene jar, the 1h that dry grinds, rotating speed 500rpm in the frequency conversion planetary ball mill.

(6) to add 8% massfraction be press forming behind 2% the PVA to dry grinding back powder.

(7) base substrate of press forming is warming up to 500 ℃ with 5 ℃/min in resistance furnace, is incubated 2h, furnace cooling in the air atmosphere.

(8) pretreated base substrate is warming up to 900 ℃ with 5 ℃/min, is incubated 2h, furnace cooling again in 900 ℃ of air atmospheres.

The Zinc-oxide piezoresistor of present embodiment made is through performance test, and potential gradient reaches 1300V/mm, leakage current 3.6 μ A, and nonlinear factor is 45.

Embodiment 2

In the present embodiment, be ZnO 94.5% by mol ratio, MnO ₂0.5%, Co ₂O ₃0.8%, Bi ₂O ₃0.7%, Cr ₂O ₃0.5%, Sb ₂O ₃1.0%, Y (NO ₃) ₃2.0%, mix the formation zinc oxide piezoresistive material, above-mentioned materials adopts the processing step identical with embodiment 1 to be made into zinc oxide pressure-sensitive ceramic.

The Zinc-oxide piezoresistor of present embodiment made is through performance test, and potential gradient reaches 1230V/mm, leakage current 4.6 μ A, and nonlinear factor is 46.

Embodiment 3

In the present embodiment, be ZnO 96.34% by mol ratio, MnO ₂0.5%, Co ₂O ₃0.8%, Bi ₂O ₃0.7%, Cr ₂O ₃0.5%, Sb ₂O ₃1.0%, Y (NO ₃) ₃0.16%, mix the formation zinc oxide piezoresistive material, above-mentioned materials adopts the processing step identical with embodiment 1 to be made into zinc oxide pressure-sensitive ceramic, and difference from Example 1 is that the sintering temperature of sintering circuit is 1000 ℃.

The Zinc-oxide piezoresistor of present embodiment made is through performance test, and potential gradient reaches 1050V/mm, leakage current 8.7 μ A, and nonlinear factor is 32.

Claims (2)

1. rare earth nitrate doping Zinc oxide pressure-sensitive ceramic material, it is characterized in that this material comprises following component by mole per-cent: ZnO 94-98% is a material of main part, MnO ₂, Co ₂O ₃, Bi ₂O ₃, Cr ₂O ₃, Sb ₂O ₃Respectively be 0.1-1.0%, rare earth nitrate is 0.01-2.0%, and wherein rare earth nitrate is a kind of in Yttrium trinitrate, praseodymium nitrate or the strontium nitrate.

2. a preparation method who is used for the described rare earth nitrate doping Zinc oxide pressure-sensitive ceramic material of claim 1 is characterized in that this method comprises the steps:

1) prepares burden by the described rare earth nitrate doping Zinc oxide pressure-sensitive ceramic material of claim 1 component, adopt zirconia ball, polyethylene jar, dehydrated alcohol and distilled water are ball-milling medium, wet-milling 5h in the frequency conversion planetary ball mill, rotating speed 500rpm, zirconia ball: the batching powder: dehydrated alcohol: the mass ratio of distilled water is 100: 5: 18: 2; The slurry that ball milling is good becomes dry powder behind 70 ℃ of baking 24h, 700 ℃ of calcining 2h;

2) powder after the calcining adopts zirconia ball, polyethylene jar, the 1h that dry grinds, rotating speed 500rpm in the frequency conversion planetary ball mill; It is press forming behind 2% the PVA that dry grinding back powder adds 8% mass concentration;

3) base substrate of press forming is warming up to 500-600 ℃ with 5 ℃/min in resistance furnace, is incubated 2h, furnace cooling in the air atmosphere; Pretreated base substrate is warming up to 900-1200 ℃ with 5 ℃/min, is incubated 2h again in 900-1200 ℃ of air atmosphere, and furnace cooling promptly gets the rare earth nitrate doping Zinc oxide pressure-sensitive ceramic material.