阅读说明：本技术 大通流容量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 (Zinc oxide varistor ceramic material with large through-flow capacity, preparation method thereof and preparation method of resistor thereof ) 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：本发明公开了大通流容量氧化锌压敏电阻陶瓷材料,包括主材料和改性剂,所述的主材料由以下摩尔百分比的原料组成：氧化锌92～95 mol%,氧化铋0.8～1.5 mol%,氧化锑1.2～1.5 mol%,三氧化二钴1.0～1.5 mol%,碳酸锰1.0～1.5 mol%,三氧化二镍0.5～1.0 mol%,氧化铬0.5～1.0 mol%,改性剂为由占主材料的质量百分比为以下比例的原料组成：钨酸盐0.2～1%,铟化物0.2～0.5%,九水合销酸铝0.01～0.05%。本发明还公开了大通流容量氧化锌压敏电阻陶瓷材料的制备方法,以及大通流容量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改性剂,形成了晶粒分布均匀,完整致密的陶瓷结构,极大的提高了通流容量,提升了产品的可靠性和安全性。(The invention discloses a zinc oxide varistor ceramic material with large through-flow capacity, which comprises a main material and a modifier, wherein the main material consists of the following raw materials in mole percentage: 92-95 mol% of zinc oxide, 0.8-1.5 mol% of bismuth oxide, 1.2-1.5 mol% of antimony oxide, 1.0-1.5 mol% of cobaltous oxide, 1.0-1.5 mol% of manganese carbonate, 0.5-1.0 mol% of nickel oxide, 0.5-1.0 mol% of chromium oxide, and the modifier is composed of the following raw materials in percentage by mass of the main material: 0.2-1% of tungstate, 0.2-0.5% of indium compound and 0.01-0.05% of aluminum nitrate nonahydrate. The invention also discloses a preparation method of the zinc oxide varistor ceramic material with large flow capacity and a preparation method of the zinc oxide varistor with large flow capacity.)

1. The zinc oxide varistor ceramic material with large through-flow capacity is characterized in that: the modifier comprises a main material and a modifier, wherein the main material comprises the following raw materials in percentage by mole:

92-95 mol% of zinc oxide

0.8 to 1.5 mol% of bismuth oxide

1.2-1.5 mol% of antimony oxide

1.0 to 1.5 mol% of cobaltous oxide

1.0-1.5 mol% of manganese carbonate

0.5 to 1.0 mol% of nickel sesquioxide

0.5 to 1.0 mol% of chromium oxide

The modifier is composed of the following raw materials in percentage by mass:

0.2-1% of tungstate, 0.2-0.5% of indium compound and 0.01-0.05% of aluminum nitrate nonahydrate.

2. The large-flow-capacity zinc oxide varistor ceramic material of claim 1, wherein: the modifier also comprises a plurality of raw materials which account for the following mass percentage of the main material:

0-0.5% of zirconium dioxide, 0-0.5% of silicon dioxide, 0-0.05% of silver nitrate and 0-0.1% of boron oxide.

3. The large-flow-capacity zinc oxide varistor ceramic material of claim 1, wherein: the tungstate is zinc tungstate.

4. The large-flow-capacity zinc oxide varistor ceramic material of claim 1, wherein: the indium compound is indium antimonide.

5. The preparation method of the zinc oxide varistor ceramic material with large through-flow capacity is characterized by comprising the following steps: the zinc oxide varistor ceramic material with large through-flow capacity of any claim 1 to 4 is prepared by the following steps,

s1, weighing and mixing the main material and the modifier in proportion to obtain the raw material,

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 μm, adding a binder, mixing uniformly to obtain a grinding material,

and S3, adding the grinding materials into a spray granulation tower for spray granulation to obtain the zinc oxide voltage-sensitive ceramic material powder with large through flow capacity.

6. The preparation method of the zinc oxide varistor ceramic material with large through-flow capacity of claim 5, characterized by: in step S2, the raw materials are: grinding medium: water =1:5:0.5 mass ratio was added to the ball mill.

7. The preparation method of the zinc oxide varistor ceramic material with large through-flow capacity of claim 5 or 6, characterized in that: the grinding medium is zirconia ball grinding beads, and the binder is acrylic acid binder.

8. The preparation method of the zinc oxide piezoresistor with large through-flow capacity is characterized by comprising the following steps: the zinc oxide varistor ceramic material with large through-flow capacity prepared by the method of any one of claims 5 to 7 is formed into 3.2g/cm³~3.3g/cm³Heating the green body to 1150-1200 ℃ 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 safe operation of electronic power, communication and transportation equipment directly influences the survival development, and the through-current capacity is used as an important index of the zinc oxide piezoresistor, so that the reliability and the safety of the product are directly determined, and therefore, the developed zinc oxide piezoresistor porcelain with large through-current capacity can well meet the requirement of the market on the high-performance piezoresistor.

The invention patent with publication number 105481363A discloses a zinc oxide varistor ceramic with large through-current capacity, low residual voltage and high gradient, which reduces leakage current and realizes large through-current capacity by adding Ag and Y elements.

Disclosure of Invention

The invention aims to provide a zinc oxide piezoresistor ceramic material, a preparation method thereof and a preparation method of a resistor thereof, so as to obtain a material with uniform and compact grains and realize large flow capacity. In order to achieve the purpose, the invention adopts the following technical scheme:

the invention discloses a zinc oxide varistor ceramic material with large through-flow capacity, which comprises a main material and a modifier, wherein the main material comprises the following raw materials in mole percentage: 92-95 mol% of zinc oxide, 0.8-1.5 mol% of bismuth oxide, 1.2-1.5 mol% of antimony oxide, 1.0-1.5 mol% of cobaltous oxide, 1.0-1.5 mol% of manganese carbonate, 0.5-1.0 mol% of nickel oxide and 0.5-1.0 mol% of chromium oxide, wherein the modifier is composed of the following raw materials in percentage by mass of the main material: 0.2-1% of tungstate, 0.2-0.5% of indium compound and 0.01-0.05% of aluminum nitrate nonahydrate.

Further, the modifier also comprises a plurality of raw materials which account for the following mass percentage of the main material:

0-0.5% of zirconium dioxide, 0-0.5% of silicon dioxide, 0-0.05% of silver nitrate and 0-0.1% of boron oxide.

Preferably, the tungstate is zinc tungstate. The indium compound is indium antimonide.

The invention also discloses a preparation method of the zinc oxide varistor ceramic material with large flow capacity, which comprises the following steps:

s1, weighing and mixing the main material and the modifier in proportion to obtain the raw material.

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, 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 zinc oxide voltage-sensitive ceramic material powder with large through flow capacity.

Preferably, in step S2, the raw materials: grinding medium: water was added to the ball mill in a mass ratio of 1:5: 0.5.

Wherein, the grinding medium is zirconia ball grinding beads, and the binder is acrylic binder.

The invention also discloses a preparation method of the zinc oxide varistor with large through-flow capacity, the zinc oxide varistor ceramic material with large through-flow capacity is prepared by the method and is molded into 3.2g/cm³～3.3g/cm³The blank body is heated to 1150-1200 ℃ in the air atmosphere for sintering,and obtaining 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 a finished zinc oxide piezoresistor.

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

1. according to the invention, the modifier is added into the main material of the zinc oxide varistor ceramic material, and the addition of the modifier influences the composition distribution and microstructure of the zinc oxide sintered body, so that a ceramic structure with uniform crystal grain distribution, integrity and compactness is formed, the material defects are few, the through-flow capacity is greatly improved, the reliability and safety of the product are improved, and the economic benefit is good.

2. The modifier zinc tungstate is added, the zinc tungstate is segregated in a grain boundary layer to form a pinning effect, abnormal growth of grains is hindered, grain growth is refined, and meanwhile, the zinc tungstate enters the grain boundary and then has the function of clamping the energy level of impurity ions, so that the grain boundary potential barrier is improved, and the through-flow capacity is improved. Adding modifier indium antimonide, In indium antimonide³⁺Form interstitial solid solution with ZnO crystal grains, In³⁺The forbidden band range is small, the electron mobility is large, the resistance of crystal grains is favorably reduced, the crystal grains are made semi-conductive, and the through-flow capacity of the material is improved.

Drawings

FIG. 1 is an electron micrograph of the untreated surface of a large flow capacity zinc oxide varistor of test specimen No. 1 according to example 1 of the present invention.

FIG. 2 is an electron micrograph of an untreated surface of a comparative zinc oxide varistor of inventive example No. 1.

Fig. 3 is an electron microscope image of a test sample large-flow-capacity zinc oxide varistor of example No. 1 of the present invention after surface treatment.

FIG. 4 is an electron micrograph of a comparative zinc oxide varistor of inventive example No. 1 after surface treatment.

Detailed Description

In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

The embodiment discloses a zinc oxide varistor ceramic material with large through-flow capacity, which comprises a main material and a modifier, wherein the main material comprises the following raw materials in mole percentage: 92-95 mol% of zinc oxide (ZnO), and bismuth oxide (Bi)₂O₃)0.8 to 1.5 mol% of antimony oxide (Sb)₂O₃) 1.2-1.5 mol% of cobalt oxide (Co)₂O₃)1.0 to 1.5 mol% of manganese carbonate (MnCO)₃)1.0 to 1.5 mol% of nickel sesquioxide (Ni)₂O₃)0.5 to 1.0 mol% of chromium oxide (Cr)₂O₃)0.5 to 1.0 mol%. The above main materials can be obtained by direct purchase. The proportioning composition of the main materials can be shown in table 1, and the proportioning schemes of 8 embodiments (M1-M8) are listed in table 1.

TABLE 1 Main Material of Zinc oxide varistor ceramic material with large flow capacity

The modifier is composed of the following raw materials in percentage by mass: 0.2-1% of tungstate, 0.2-0.5% of indium compound and aluminum nonahydrate (AlNO)₃.9H₂0.01 to 0.05% of O), zirconium dioxide (ZrO)₂)0 to 0.5% of silicon dioxide (SiO)₂) 0-0.5%, silver nitrate (AgNO)₃)0 to 0.05% of boron oxide (B)₂O₃)0 to 0.1%. Wherein the tungstate may be zinc tungstate (ZnWO)₄) Bismuth tungstate (Bi)₂O₁₂W₃) Cobalt tungstate (CoWO)₄) Manganese tungstate (MnO)₄W), etc., zinc tungstate (ZnWO) is selected for this example₄). Indium antimonide (InSb) is selected as the indium compound. The formulation composition of the modifier can be shown in table 2, and table 2 lists 16 embodiments.

TABLE 2 high-flux zinc oxide varistor ceramic material

The invention discloses a preparation method of the zinc oxide varistor ceramic material with large through-flow capacity, which comprises the following steps.

S1, weighing and mixing the main materials and the modifier 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 1:5:0.5, and mixing in the ball mill until the particle size is less than 1 μm. The grinding medium is zirconia ball grinding beads, and the grinding time is more than 9H. And then adding a binder, wherein the binder is an acrylic acid binder, and uniformly mixing to obtain the abrasive.

And S3, adding the grinding material into a spray granulation tower for spray granulation to obtain the zinc oxide voltage-sensitive ceramic material powder with large through flow capacity.

The invention also discloses a preparation method of the zinc oxide piezoresistor with large through flow capacity, which adopts the following steps.

S1-S4. obtaining the zinc oxide varistor ceramic material with large through-flow capacity by the same preparation steps.

S5, forming the prepared zinc oxide varistor ceramic material with large through-flow capacity 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 1150-1200 ℃ 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 zinc oxide piezoresistor with large through-flow capacity prepared by the method is tested as follows.

The preparation method of the invention (adopting the proportioning raw materials in Table 2) prepares 16 groups of large-through-flow capacity zinc oxide piezoresistor test samples according to the sintering temperature in Table 3, and simultaneously adds 16 groups of corresponding comparison samples, the main materials of the comparison samples are the same as the examples in Table 2, and the modifier of the comparison samples is not added with zinc tungstate (ZnWO)₄) And indium antimonide (InSb), the remaining modifiers are in accordance with table 2.

The 16 groups of test samples and the 16 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 the 10KA impact is carried out once, so that the test results in the table 3 are obtained.

TABLE 3 through-flow Capacity test experiment

Table 3 shows that when the embodiment of the invention is sintered at the temperature of 1150-1200 ℃, the product realizes large through-flow capacity, reaches 10KA/cm2, and meets the requirement of the product on large through-flow capacity. And the comparative sample is sintered at 1150-1200 ℃, and all the samples are cracked and failed under 10KA impact.

The structure of the test sample of example No. 1 and the comparative sample in table 3 was observed under an electron microscope, and fig. 1 to 4 were obtained, in which fig. 1 and 3 are electron micrographs of the test sample, and fig. 2 and 4 are electron micrographs of the comparative sample. As can be seen from the figure, the ceramic-like surface grain shape of the zinc oxide piezoresistor with large through-flow capacity prepared by the invention has uniform appearance, good consistency, compact structure and few cavities. And the surface crystal grains of the comparison sample are different in size, more in cavities and poor in compactness. According to the invention, modifiers tungstate and indium compounds are added in the formula, the modifier doped particles influence the microstructure of the zinc oxide sintered body, different structural distributions are generated by utilizing the characteristics of the doped particles, abnormal growth of crystal grains is inhibited by controlling the proportion of the doped particles, and the sintered body with uniform crystal grain distribution and complete and compact crystal grain boundary structure is obtained, so that the zinc oxide pressure-sensitive ceramic material with large through-flow capacity of 10KA/cm2 is obtained by sintering the material formula at 1150-1200 ℃.

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.