阅读说明：本技术 低温烧结氧化锌压敏电阻陶瓷材料、其制备方法及其电阻器的制备方法 (Low-temperature sintered zinc oxide varistor ceramic material, preparation method thereof and preparation method of resistor ) 是由 李经仁 林康 邹海雄 张军志 于 2019-09-30 设计创作，主要内容包括：本发明公开了低温烧结氧化锌压敏电阻陶瓷材料,包括主材料及助烧剂,主材料由以下摩尔百分比的原料组成：氧化锌93～96mol%,氧化铋1～1.5 mol%,氧化锑1～1.5 mol%,三氧化二钴0.8～1.5 mol%,碳酸锰0.7～1.0 mol%,三氧化二镍0.5～1.5 mol%。助烧剂为由占主材料的质量百分比为以下比例的原料组成：硼酸锌0.2～1%。本发明还公开了低温烧结氧化锌压敏电阻陶瓷材料的制备方法,以及低温烧结氧化锌压敏电阻器的制备方法,本发明通过在氧化锌压敏电阻陶瓷材料的主材料内添加助烧剂,以实现在低温烧结时保证烧结的致密度,减少挥发,提高产品的性能。(The invention discloses a low-temperature sintered zinc oxide varistor ceramic material, which comprises a main material and a sintering aid, wherein the main material consists of the following raw materials in mole percentage: 93-96 mol% of zinc oxide, 1-1.5 mol% of bismuth oxide, 1-1.5 mol% of antimony oxide, 0.8-1.5 mol% of cobaltous oxide, 0.7-1.0 mol% of manganese carbonate and 0.5-1.5 mol% of nickel oxide. The sintering aid is composed of the following raw materials in percentage by mass: 0.2-1% of zinc borate. The invention also discloses a preparation method of the low-temperature sintered zinc oxide varistor ceramic material and a preparation method of the low-temperature sintered zinc oxide varistor ceramic material.)

1. The low-temperature sintered zinc oxide varistor ceramic material is characterized in that: the sintering aid comprises a main material and a sintering aid, wherein the main material comprises the following raw materials in percentage by mole:

93-96 mol% of zinc oxide

1-1.5 mol% of bismuth oxide

1-1.5 mol% of antimony oxide

0.8 to 1.5 mol% of cobaltous oxide

0.7-1.0 mol% of manganese carbonate

0.5-1.5 mol% of nickel sesquioxide;

the sintering aid is composed of the following raw materials in percentage by mass:

0.2-1% of zinc borate.

2. The low temperature sintered zinc oxide varistor ceramic material of claim 1, wherein: the composite material also comprises a trace additive, wherein the trace additive is composed of the following raw materials in percentage by mass:

0.01-0.05% of nonaaluminum nitrate and 0.01-0.05% of silver nitrate.

3. The low temperature sintered zinc oxide varistor ceramic material of claim 1 or 2, wherein: the sintering aid also comprises a plurality of raw materials which account for the following mass percentage of the main materials:

0-1% of tin oxide, 0-1% of basic zinc carbonate and 0-1% of zinc silicate.

4. The preparation method of the low-temperature sintered zinc oxide varistor ceramic material is characterized by comprising the following steps: the low-temperature sintered zinc oxide varistor ceramic material as claimed in any of claims 1 to 3 is prepared by the following steps,

s1, weighing and mixing the raw materials in proportion to obtain raw materials;

s2, adding the raw materials into a ball mill, adding a grinding medium and water into the ball mill, mixing in the ball mill until the particle size is less than 1 mu m, then adding a binder, and uniformly mixing to obtain a grinding material;

and S3, adding the grinding materials into a spray granulation tower for spray granulation to obtain the low-temperature sintered zinc oxide voltage-sensitive ceramic material.

5. The method for preparing the low-temperature sintered zinc oxide varistor ceramic material of claim 4, wherein: in step S2, the raw materials are: grinding medium: water =1:4:0.5 mass ratio was added to the ball mill.

6. The method for preparing the low-temperature sintered zinc oxide varistor ceramic material according to claim 4 or 5, characterized in that: the grinding medium is zirconia ball grinding beads, and the binder is acrylic acid binder.

7. The preparation method of the low-temperature sintered zinc oxide piezoresistor is characterized by comprising the following steps: the low-temperature sintered zinc oxide varistor ceramic material prepared by the method of any one of claims 4 to 6 is formed into 3.2g/cm³~3.3g/cm³Heating the green body to 950-1050 ℃ in air atmosphere, sintering to obtain a zinc oxide piezoresistor ceramic chip, printing a silver electrode, reducing at 560-580 ℃ to obtain a zinc oxide piezoresistor chip, and welding and encapsulating to obtain the finished zinc oxide piezoresistor.

Technical Field

The invention relates to the technical field of resistance materials, in particular to a zinc oxide piezoresistor ceramic material, a preparation method thereof and a preparation method of a zinc oxide piezoresistor.

Background

The zinc oxide piezoresistor is taken as a mainstream protective device, and along with the improvement of the safety protection consciousness of human living and life, the application of the zinc oxide piezoresistor is more and more extensive: for example, the material has wide application prospects in the aspects of absorbing atmospheric overvoltage and operation overvoltage, application in superconducting energy transfer, field suppression of generator sets, electric equipment, semiconductor devices, overvoltage protection of various motors and the like in power systems and electronic circuits.

The zinc oxide varistor ceramic material is a functional material mainly containing zinc oxide, a Sb-Bi-Co-Mn-Ni-Cr system material is adopted in the traditional zinc oxide varistor formula, the sintering temperature is high due to the existence of chromium oxide serving as a raw material, the sintering temperature needs to reach over 1100 ℃, the bismuth oxide in the formula material is easy to volatilize at high temperature, the proportion deviation is caused, meanwhile, the volatilization of the bismuth oxide generates a large number of defects to influence the product performance, and if the sintering temperature is reduced, the sintering cannot be completed, the ceramic body has a plurality of structural defects, the through-flow capacity of the product is low, and the use requirement of the product cannot be met.

Disclosure of Invention

The invention aims to provide a zinc oxide varistor ceramic material, a preparation method thereof and a preparation method of a resistor thereof, so as to ensure the sintering density during low-temperature sintering and reduce volatilization and structural defects. In order to achieve the purpose, the invention adopts the following technical scheme:

the invention discloses a low-temperature sintered zinc oxide varistor ceramic material, which comprises a main material and a sintering aid, wherein the main material consists of the following raw materials in mole percentage: 93-96 mol% of zinc oxide, 1-1.5 mol% of bismuth oxide, 1-1.5 mol% of antimony oxide, 0.8-1.5 mol% of cobaltous oxide, 0.7-1.0 mol% of manganese carbonate and 0.5-1.5 mol% of nickel oxide.

The sintering aid is composed of the following raw materials in percentage by mass: 0.2-1% of zinc borate.

Further, the material also comprises a trace additive, wherein the trace additive is composed of the following raw materials in percentage by mass: 0.01-0.05% of nonaaluminum nitrate and 0.01-0.05% of silver nitrate.

Further, the sintering aid also comprises a plurality of raw materials which account for the following proportions of the main materials in percentage by mass:

0-1% of tin oxide, 0-1% of basic zinc carbonate and 0-1% of zinc silicate.

The invention discloses a preparation method of a low-temperature sintered zinc oxide varistor ceramic material, which is prepared by adopting the low-temperature sintered zinc oxide varistor ceramic material according to the following steps.

S1, weighing and mixing the raw materials in proportion to obtain the raw materials.

S2, adding the raw materials into a ball mill, adding a grinding medium and water into the ball mill, mixing in the ball mill until the particle size is less than 1 mu m, then adding a binder, and uniformly mixing to obtain a grinding material;

and S3, adding the grinding material into a spray granulation tower for spray granulation to obtain the low-temperature sintered zinc oxide voltage-sensitive ceramic material.

Wherein in step S2, the raw materials are as follows: grinding medium: water was added to the ball mill in a mass ratio of 1:4: 0.5.

Preferably, the grinding medium is zirconia ball milling beads, and the binder is an acrylic binder.

The invention also discloses a preparation method of the low-temperature sintered zinc oxide piezoresistor, which adopts the low-temperature sintered zinc oxide piezoresistor ceramic material to form the zinc oxide piezoresistor into 3.2g/cm³～3.3g/cm³Heating the green body to 950-1050 ℃ in air atmosphere, sintering to obtain a zinc oxide piezoresistor ceramic chip, printing a silver electrode, reducing at 560-580 ℃ to obtain a zinc oxide piezoresistor chip, and welding and encapsulating to obtain the finished zinc oxide piezoresistor.

Due to the adoption of the structure, the invention has the following beneficial effects:

1. the main material does not contain chromium oxide which is difficult to sinter, zinc borate is used as a sintering aid, low-temperature liquid-phase sintering of a product can be realized, and meanwhile, the introduction of zinc borate avoids a complex reaction with a binder in a spray granulation process during preparation, so that the uniformity of slurry is ensured, the sintering uniformity of powder is improved, and the performance of the product is ensured.

2. The invention adds trace additive aluminum nitrate nonahydrate in the formula, and the function is as follows: al (Al)³⁺It can be dissolved in oxygen ZnO crystal grain to form substitutional solid solution when Al is used³⁺Substituted divalent Zn²⁺In order to ensure electroneutrality, Zn²⁺To Zn⁺A univalent effective positive point center is formed, so that the conductive electrons in the ZnO crystal grains are increased rapidly, the crystal grain resistance is reduced, the residual voltage is reduced, and the performance of the product is facilitated. Adding a trace additive AgNO₃The functions of the method are as follows: ag⁺The radius is large, and the crystal grain boundary stabilizer is segregated on a crystal boundary during sintering, can effectively hinder and clamp the migration of ions between crystal boundary layers, is a crystal boundary stabilizer, is favorable for improving the stability of products and prolongs the service life.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the present invention is further described in detail with reference to the specific embodiments below.

The embodiment discloses a low-temperature sintered zinc oxide varistor ceramic material which comprises a main material, a sintering aid and a trace additive. The main material comprises the following raw materials in percentage by mole: zinc oxide (ZnO) to 96mol%, bismuth oxide (Bi)₂O₃)1 to 1.5 mol% of antimony oxide (Sb)₂O₃) 1-1.5 mol% of cobalt oxide (Co)₂O₃) 0.8-1.5 mol% of manganese carbonate (MnCO)₃)0.7 to 1.0 mol% of nickel sesquioxide (Ni)₂O₃)0.5 to 1.5 mol%. The above mainThe materials are available by direct purchase. The proportioning composition of the main materials can be shown in table 1, and the proportioning schemes of 9 embodiments (M1-M9) are listed in table 1.

TABLE 1 Main Material of Low-temperature sintered Zinc oxide varistor ceramic Material

The sintering aid is composed of the following raw materials in percentage by mass: zinc borate (ZnHBO)₃) 0.2-1%, tin oxide (SnO)₂)0 to 1% of basic zinc carbonate (Zn)₂(OH)₂CO₃)0 to 1% of zinc silicate (Zn)₂SiO₄)0 to 1 percent. The trace additive is composed of the following raw materials in percentage by mass: aluminum nitrate nonahydrate (AlNO)₃.9H₂0.01-0.05% of O) and silver nitrate (AgNO)₃)0.01 to 0.05 percent. The composition of the sintering aid and the trace additive in a ratio can be shown in table 2, and table 2 lists 18 embodiments.

TABLE 2 composition of combustion improver and trace additive

The invention discloses a preparation method of the low-temperature sintered zinc oxide varistor ceramic material, which comprises the following steps.

S1, weighing and mixing the main material, the sintering aid and the trace additive according to the proportion shown in the table 1 and the table 2 to obtain the raw materials.

S2, adding the raw materials into a ball mill, adding a grinding medium and water into the ball mill, and mixing the raw materials: grinding medium: adding water into a ball mill according to the mass ratio of 1:4:0.5, and mixing in the ball mill until the particle size is less than 1 μm. The grinding medium is zirconia ball-milling beads, and the grinding time is more than 9H. And then adding a binder, and uniformly mixing to obtain the grinding material. The adhesive is acrylic adhesive.

And S3, adding the grinding material into a spray granulation tower for spray granulation to obtain the low-temperature sintered zinc oxide voltage-sensitive ceramic material.

The invention also discloses a preparation method of the low-temperature sintered zinc oxide piezoresistor, which comprises the following steps.

S1-S3. the low-temperature sintered zinc oxide varistor ceramic material is obtained by the same preparation steps.

S4, forming the prepared low-temperature sintered zinc oxide varistor ceramic material into a disc-shaped blank (the density is 3.2 g/cm) with the diameter of 16.4mm and the thickness of 2.5mm under the pressure of 6MP³～3.3g/cm³) Heating to 950-1050 ℃ in air atmosphere, sintering to obtain a zinc oxide piezoresistor ceramic chip, printing a silver electrode with the diameter of 11mm, reducing at 580 ℃ to obtain a zinc oxide piezoresistor chip, and welding and encapsulating to obtain the finished zinc oxide piezoresistor.

The low temperature sintered zinc oxide varistor prepared according to the present invention was tested as follows.

The preparation method of the invention (adopting the proportioning raw materials in Table 2) prepares 18 groups of low-temperature sintering zinc oxide piezoresistor test samples according to the sintering temperature in Table 3, and simultaneously, 18 groups of comparison samples I and 18 groups of comparison samples II are added, the main material and the trace additive of the comparison sample I are the same as those in Table 2, and no sintering aid is added in the comparison sample I. The main material and the sintering aid of comparative sample two were the same as those in table 2, but no trace additive was added to comparative sample two.

The 18 groups of test samples and the 18 groups of comparison samples are placed on a pressure-sensitive tester to test pressure-sensitive parameters, the through-current capacity is tested by an M20 surge generator, and 8KA impact is performed once to obtain the test results in the table 3.

TABLE 3 through-flow Capacity test experiment

Table 3 shows that when the embodiment of the invention is sintered at the low temperature of 950-1050 ℃, the product realizes larger through-flow capacity which reaches 8KA/cm²And the performance is excellent. And under the condition that no sintering aid is added in the formula, the sintering cannot be completely sintered at low temperature, so that the porcelain body has a plurality of structural defects, the through-flow capacity of the product is low, and the porcelain body is cracked and fails under the 8KA impact. And when trace additives are not added in the formula, the residual pressure is higher, and the through-flow change rate is poorer.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.