CN112951532B - A kind of high gradient resistance sheet and its manufacturing method - Google Patents

Abstract

The invention discloses a high gradient resistance sheet and a manufacturing method thereof. In the method, the composition of the resistance sheet itself is optimized, and the whole preparation process is adjusted according to the change of the composition. In the process of mixing additives and zinc oxide, the mixing of zinc oxide and additives is achieved by the method of high-speed planetary stirring and high-speed dispersion of colloidal ball milling, and the particles of zinc oxide and additives are further ground into finer particles. During the molding process, the pressing curve of five times of exhaust and one pressure-holding molding is adopted, so that the cylindricity, end face parallelism, and the perpendicularity error of the end face and the axis of the resistor sheet are kept below 0.02mm. In order to ensure the arrester The operability of the assembly process lays a solid foundation. The successful development of the resistor sheet not only reduces the manufacturing cost of the resistor sheet, but also greatly reduces the size of the arrester.

Description

A high-gradient resistor chip and its manufacturing method

【Technical field】

The invention belongs to the technical field of resistance sheets, and in particular relates to a high-gradient resistance sheet and a manufacturing method thereof.

【Background technique】

With the development of the power industry, the requirements for overvoltage protection of the power system are getting higher and higher, and the development of zinc oxide arresters specially used for overvoltage protection equipment has not made a major breakthrough due to the limitations of technical research and development. At present, the manufacturing technology adopted by the domestic arrester industry is still based on the introduction of Japanese technology as the mainstream, and the domestic process improvement as the auxiliary production method. In particular, the manufacturing technology of the zinc oxide resistor, the core component of the arrester, still adopts the technology imported from Japan. Although its production cost has decreased with the improvement of equipment automation, but with the rise of domestic labor costs, the total manufacturing cost of zinc oxide resistors has remained high, which limits the development and improvement of arrester technology.

【Content of invention】

The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art, and provide a high-gradient resistance sheet and a manufacturing method thereof, so as to solve the problems of high preparation cost and immature preparation process of the zinc oxide resistance sheet in the prior art.

In order to achieve the above object, the present invention adopts the following technical solutions to achieve:

A method for manufacturing a high-gradient resistor sheet, comprising the following steps:

Step 1, grinding and mixing bismuth oxide, cobalt oxide, antimony oxide, nickel oxide, manganese oxide, chromium oxide and silicon dioxide through a grinder to obtain additives; in terms of mass percentage, the mass fraction of bismuth oxide is 3-5% , the mass fraction of cobalt oxide is 1.5-3.5%, the mass fraction of antimony oxide is 4-6%, the mass fraction of nickel oxide is 0.1-0.5%, the mass fraction of manganese oxide is 0.8-2.0%, and the mass fraction of chromium oxide 0.6-1.5%, the mass fraction of silicon dioxide is 1-3%;

Step 2, adding additives and zinc oxide into the mixer, and after mixing, ball milling in a ball mill to obtain granulated material; wherein the mass fraction of zinc oxide is 82% to 89%, and the content of zinc oxide and each substance in step 1 is The sum of the materials is 100%;

Step 3, pressing and molding the granulated material, performing several times of exhaust during the molding process, and one-time pressure-holding molding to obtain a process resistance sheet;

Step 4, sintering the process resistance sheet to obtain a sintered resistance sheet;

Step 5, spraying aluminum electrodes on the surface of the sintered resistor sheet to obtain a high-gradient resistor sheet.

A further improvement of the present invention is:

Preferably, in step 1, the sanding medium is zirconia beads with a diameter of 0.4 to 0.5 mm, and the D50 particles after grinding are less than 0.4 μm.

Preferably, in step 2, the solid content in the mixer is 58-63%.

Preferably, in step 3, each exhaust time is 4-6s, the pressure holding time is 8-20s, and the number of exhausts is 5-7 times.

Preferably, in step 4, sintering includes pre-sintering, firing and heat treatment.

Preferably, the pre-burning temperature is 700°C-950°C, and the pre-burning time is 3-10 hours.

Preferably, the firing temperature is 1100-1200°C, and the firing holding time is not less than 10h.

Preferably, the temperature of the heat treatment is 600°C-700°C, and the temperature is kept at the target temperature for 2-3 hours.

Preferably, during the heat treatment process, the rate of temperature rise from room temperature to the target heat treatment temperature is 150°C/hour, and the temperature drop rate after the target holding time is 80°C/hour;

Before heat treatment, the sides of the fired resistors are coated with a layer of lead-free glass glaze.

Preferably, the thickness of the aluminum electrode on the surface of the resistance sheet is 0.07mm-0.1mm, and the gradient of the resistance sheet is 300-330V/mm.

Compared with the prior art, the present invention has the following beneficial effects:

The invention discloses a method for manufacturing a high-gradient resistance sheet. In the method, the composition of the resistance sheet itself is optimized, and the entire preparation process is adjusted according to the change of the composition. In the preparation process, firstly, the additive is ground and mixed by a grinder , in the mixing process of additives and zinc oxide, the method of planetary high-speed stirring and stirring ball milling is used to achieve uniform mixing and particle grinding of zinc oxide and additives. This method increases the ball milling cycle process in the granulation process, making zinc oxide slurry In the process of uniform dispersion and emulsification of the material, the particles of zinc oxide and additives are further ground finer. During the forming process, the compression curve of five times of exhaust and one time of pressure keeping is adopted, so that the cylindricity, end face parallelism, and perpendicularity error between the end face and the resistor sheet axis of the fired resistor sheet are kept below 0.02mm. The operability of the assembly process has laid a solid foundation. The successful research and development of the resistance sheet not only reduces the manufacturing cost of the resistance sheet, but also greatly reduces the overall size of the arrester.

Further, during the mixing process, zirconia beads are added for grinding, and the high-speed rotation of the motor drives the high-speed movement of the zirconium beads in the grinding tank, so that the additive slurry in the grinding tank is hit by the high-speed moving zirconium balls, and the additive particles are crushed. Grinding can make the particles of additives finer.

Further, through mixing with a mixer and a ball mill, the zinc oxide slurry is uniformly dispersed and emulsified, and the particles of zinc oxide and additives are further ground finer, which greatly enhances the fluidity of the granulated material. The operation of the subsequent molding process provides easier operating conditions.

Further, the sintering process is divided into three parts, including three sintering stages of pre-firing, firing, and heat treatment. Pre-firing can make the resistor chip deglue while keeping the shrinkage rate of the high-resistance layer and the resistor chip body consistent , so that the side high-resistance layer and the resistance sheet body form a ceramic whole, the high-resistance layer does not delaminate, does not fall off, and improves the ability of the side of the resistance sheet to withstand large current impacts; through the firing process, the resistance sheet is designed in the present invention. Under the same composition, the target crystal phase can be generated, so that the resistance sheet has the characteristics of high 2ms square wave resistance and excellent residual voltage protection level. Then, through heat treatment, the anti-aging performance of the resistor sheet can be further improved. It can be seen from the above process that the present invention divides the sintering process of ordinary resistors into three parts, and the three sintering processes are progressive, first controlling the deformation rate, then controlling the crystal phase, and finally improving the overall tolerance, three stages Complement each other and improve the performance of the resistor as a whole.

【Description of drawings】

Fig. 1 is a flowchart of the present invention;

【Detailed ways】

The present invention is described in further detail below in conjunction with accompanying drawing:

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, or in a specific orientation. construction and operation, and therefore cannot be construed as limiting the present invention; the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be construed as indicating or implying relative importance; in addition, unless otherwise Clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediary, Can be a communication within two elements. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

The invention discloses a high-gradient resistance sheet and a manufacturing method thereof. The composition of the high-gradient resistance sheet is:

name weight percentage Zinc oxide 82～89 bismuth oxide 3～5 cobalt oxide 1.5～3.5 Antimony oxide 4～6 Nickel oxide 0.1～0.5 manganese oxide 0.8～2.0 Chromium oxide 0.6～1.5 silica 1～3

The protective performance of zinc oxide resistors is mainly granulated material mixed with zinc oxide and other various chemical raw materials (hereinafter collectively referred to as additives). After being formed into a green body, it is sintered in a kiln. The maximum sintering temperature can be 1100 ° C ~ between 1250°C. During the high-temperature sintering process of the zinc oxide green body, a series of physical and chemical changes will occur, the specific changes are as follows: melting of low-melting additives (bismuth oxide, antimony oxide), replacement and co-melting of the additives; The melting of fine grains of zinc oxide and the growth and development of coarse grains of zinc oxide; the formation of various solid solutions, spinel phases, liquid phases, grain boundary layers, etc. The final result of this physical and chemical change is the formation of zinc oxide grains with semiconducting properties, and a layer of grain boundary layer formed by various additives during sintering is wrapped around the zinc oxide grains. It is precisely because of the pressure-sensitive characteristics of the grain boundary layer that the zinc oxide grains have nonlinear pressure-sensitive protection characteristics.

The invention adopts an eight-component formula. Due to the different roles played by various oxides in the zinc oxide grain boundary layer during the sintering process of the resistance sheet, the amount of its addition is adjusted. The main adjustment is to combine antimony oxide and The amount of silicon increases.

⑴Increase the amount of antimony oxide, because antimony trioxide is the main additive component for the formation of antimony-zinc spinel phase, the main function of spinel is because it is located at the intersection of zinc oxide grains, inhibiting oxidation during sintering The growth of zinc grains is conducive to the uniform development of zinc oxide grains, which can significantly increase the breakdown voltage, thereby achieving the purpose of increasing the potential gradient.

⑵Increase the amount of silicon dioxide, silicon dioxide forms a viscous glass phase with bismuth oxide and zinc oxide during the sintering process of the resistor, and in the cooling process, silicon dioxide mostly exists in the form of zinc silicate at the grain boundary layer and the intersection of zinc oxide grains, and because it increases the viscosity of the glass phase, it has the effect of inhibiting the growth of zinc oxide grains. Therefore, the effect of silicon dioxide and antimony oxide is similar, which determines the size of zinc oxide grains and The grain boundary layer is evenly distributed, which increases the potential barrier of the grain boundary layer and increases the potential gradient.

(3) The manufacturing process of the resistor sheet specifically includes the following steps:

Step 1, mixing materials in a grinder to form an additive, mixing all materials except zinc oxide, placing all materials in a sand mill, the sand grinding medium is zirconia beads with a diameter of 0.4-0.5mm, after sand grinding, The particles of D50 are less than 0.4μm, and a uniform mixture is obtained after mixing, which is an additive.

The additive is the main component of the grain boundary layer between zinc oxide grains, and its particle size determines the thickness of the grain boundary layer, which also determines the height of the electromotive barrier of the grain boundary layer, which is reflected in the electrical parameters of the resistor, that is, It determines the level of the withstand breakdown voltage and the level of the potential gradient of the resistor sheet. Therefore, ball milling the additive particles to the minimum particle size determines the breakdown voltage of the resistance sheet. At present, the commonly used ball milling method in the industry is to use a stirring ball mill and a slurry circulation method, which uses a diameter of 5mm in the ball mill. Zirconia balls were used as milling media. After this ball milling process, the particle diameter of the additive can be ground to a D50 of about 1 micron. In order to make the particles of additives finer, sand mill technology is used when making high potential gradient resistors. Its outstanding features are: the grinding medium uses zirconia beads with a diameter of 0.4 to 0.5mm as the grinding medium, and the grinding medium is ground under the high-speed rotation of the motor. Drive the zirconium beads in the grinding tank to move at high speed, so that the additive slurry in the grinding tank is crushed under the impact of the high-speed moving zirconium beads. After the sand milling process, the particle size of the additive can be ground to D50 in Below 0.4 microns, compared with the 1 micron particle size of the commonly used process, it is about doubled, so that the zinc oxide resistors form a more uniform grain boundary layer wrapped on the zinc oxide grains during the firing process, greatly improving the The ability of the resistor sheet to withstand the impact of current.

Step 2, granulation process

Add the additives and zinc oxide into the high-speed mixing tank, and mix with the planetary high-speed mixer at a speed of 800 rpm for more than 4 hours. During the mixing process, the solid content is 58-63%. After granulation, the particle The average particle size is 70 microns, and the bulk density is 1.55 g/cm3.

The granulation process is the most critical process in the zinc oxide resistor manufacturing process, which determines the final result of the smooth execution of the entire process. Therefore, no matter what kind of formula system, the granulation process is controlled as a process control point. The conventional granulation process adopts planetary high-speed stirring and colloid mill high-speed dispersion in the slurry emulsification stage to achieve uniform mixing of zinc oxide and additives. On the basis of this process method, the present invention adds a set of ball milling circulation process operation method, so that the particles of zinc oxide and additives are further ground finer during the process of uniform dispersion and emulsification of the zinc oxide slurry. In the control of the solid content of the slurry, the solid content of the granulated slurry of the high gradient resistor formula is controlled at about 60%, which is slightly lower than the conventional 64%. After the improvement of this process, the average particle size of the granulated material is reduced from 100 microns to about 70 microns, and the bulk density is increased from 1.3 grams per cubic centimeter to 1.55 grams per cubic centimeter, which greatly enhances the quality of the granulated materials. The fluidity provides easier operating conditions for the operation of the subsequent molding process.

Step 3, the molding process

Distribute the granules made in step 2 to the molding machine for compression molding. During the molding process, the compression curve of five exhausts and one pressure holding molding is adopted. The exhaust time is between 4 and 6 seconds, and the pressure holding time Between 8 and 20 seconds, the errors of the cylindricity, parallelism of the end face and perpendicularity between the end face and the axis of the resistor sheet after forming are all less than 0.02mm. According to the diameter of the product, determine the holding time, the larger the diameter of the product, the longer the holding time.

The forming process is the key process of converting raw materials into resistors with regular geometric shapes. Whether the density of the formed resistors is uniform and whether the exhaust is thorough will have a great impact on whether the homogeneous zinc oxide ceramics can be fired later. The present invention uses a fully digitally controlled molding machine for compression molding. During the molding process, it adopts five times of exhaust and one compression curve for pressure-holding molding. The exhaust time is between 4 and 6 seconds, and the pressure-holding time is between 8 and 20 seconds. Between, and in order to ensure the standardization of the geometric shape of the resistance sheet during the sintering process, the conventional blank density is reduced from 3.2 g/cubic centimeter to 2.8 g/cubic centimeter. Through the improvement of the above molding process, the cylindricity, end parallelism, and perpendicularity error between the end face and the resistor axis of the fired resistor are kept below 0.02mm, which has laid a solid foundation for ensuring the operability of the arrester assembly process. The basics.

Step 4, sintering process

The firing process is an important process for forming zinc oxide semiconductors. The process of putting the zinc oxide blank into the kiln for sintering is the porcelainization process of the zinc oxide resistor. The whole sintering process of the high gradient resistance chip adopts three sintering stages of pre-firing, firing and heat treatment.

Step 4.1 Burn-in

Pre-burning is to keep the resistance sheet at a maximum temperature of 700°C to 950°C for 3 to 10 hours, and keep the heating rate between 10°C and 30°C during the heating stage. The pre-firing process not only removes the glue on the resistance sheet, but also makes the shrinkage rate of the resistance sheet between 12% and 15% in the pre-firing stage, so as to ensure that the high-resistance layer and the resistance layer can be fully sealed when the high-resistance layer is coated in the next process. The shrinkage rate of the chip body is consistent, so that the side high-resistance layer and the resistor body form a ceramic whole, and the high-resistance layer does not delaminate or fall off, which improves the ability of the side of the resistor to withstand large current impacts.

Step 4.2 Firing

This stage is the ceramicization stage of resistors. The resistors fired through this process have nonlinear protection characteristics. The firing process curve adopted in the present invention is characterized by a slow heating rate and a long holding time. The specific process heating rate is 30°C/h, the target temperature is 1100-1200°C, and the holding time is not less than 10h. The resistance chip produced by this firing process curve has the characteristics of high 2ms square wave tolerance and excellent residual voltage protection level. Through the sintering process, combined with the above-mentioned component design, and by controlling the temperature and time during the sintering process, the crystal phase of the obtained resistor plate is the target crystal phase.

Step 4.3 Heat Treatment Process

Heat treatment stage: Heat treatment is to further optimize the performance of the resistance sheet, especially to improve the aging characteristics of the resistance sheet. The target temperature is 600 ° C ~ 700 ° C, the heating rate is 150 ° C / hour, and the cooling rate is 80 ° C / hour. The heat treatment curve, The heating speed of the whole heating process is fast, which can make the crystal phase be adjusted quickly. After the temperature is raised to the target temperature, the temperature is kept for 2-3 hours, and then the temperature is rapidly lowered. Moreover, before heat treatment, a layer of high-temperature lead-free glass glaze is coated on the side of the resistor. At the same time of heat treatment, the side glass glaze is sintered on the side of the resistor, which further improves the high-current impact resistance of the resistor. The manufacture of liquid-immersed arresters provides a convenient and simple process.

Step 5, Resistor Spraying Process

The sintered resistor sheet is sprayed with an aluminum electrode on the end surface of the resistor sheet by an automatic spraying machine, and the thickness of the aluminum electrode after spraying is 0.07 mm to 0.1 mm.

After the resistance sheet is sintered, the end surface of the resistance sheet is sprayed with aluminum electrodes using an automatic spraying machine. The thickness of the aluminum electrode is between 0.07mm and 0.1mm. After the electrode spraying is completed, the density of the resistance sheet is 2.8 g/cubic centimeter. The gradient of the resistor sheet is 300-330V/mm, and the manufacturing process of the entire resistor sheet is finished. According to the requirements of the national standard, the resistance sheet can be used to manufacture lightning arresters of various voltage levels and various purposes after the parameter detection of multiple items is carried out. Below in conjunction with specific embodiment the present invention is further described:

Embodiment 1: The following is a specific description by taking a resistance sheet with a diameter of Φ64mm and a height of 22mm as an example

Step 1: Granulation: 300 kg of zinc oxide per batch, plus 60 kg of additives, planetary agitator ball milling for 5 hours and then spray granulation. The physical parameters of the granulated material: (1) Average particle size: 70 microns; (2) Bulk density: 1.55 g / cubic centimeter, (3) moisture content 1.8%; (4) solid content is 60%.

Additives include 4% bismuth oxide, 3.5% cobalt oxide, 4% antimony oxide, 0.5% nickel oxide, 1% manganese oxide, 1% chromium oxide, and 3% silicon dioxide; The percentage by mass in the composition, i.e. its base is the additive and zinc oxide.

Step 2: Molding: Blank diameter: 80mm, weight 390g, pressing curve is 7 times of exhaust, exhaust time is 6 seconds, holding time is 15 seconds.

Step 3: Pre-burning: the pre-burning temperature is 900°C, and the holding time is 7 hours;

Step 4: Firing: maximum temperature 1100°C; holding time 10 hours;

Step 5: heat treatment: the maximum temperature is 650°C, and the holding time is 2 hours.

Step 6: Grinding, aluminum spraying, electrical parameter testing, finished product storage.

The detailed electrical parameters of the product are as follows:

Example 2

Step 1: Granulation: 300 kg of zinc oxide per batch, 59 kg of additives, planetary agitator ball milling for 5 hours and then spray granulation. The physical parameters of the granulated material: (1) Average particle size: 70 microns; (2) Bulk density: 1.55 g / cubic centimeter, (3) moisture content 1.8%; (4) solid content is 59%.

Additives include 4% bismuth oxide, 3.3% cobalt oxide, 5% antimony oxide, 0.1% nickel oxide, 2% manganese oxide, 1.5% chromium oxide, and 1% silicon dioxide; % by mass in the composition, i.e. its base is the additive and zinc oxide.

Step 2: Molding: Blank diameter: 80mm, weight 390g, pressing curve is 7 exhaust times, exhaust time is 6 seconds, and pressure holding time is 10 seconds.

Step 3: Pre-burning: the pre-burning temperature is 950°C, and the holding time is 3 hours;

Step 4: Firing: maximum temperature 1200°C; holding time 10 hours;

Step 5: heat treatment: the maximum temperature is 700°C, and the holding time is 2 hours.

Step 6: Grinding, aluminum spraying, electrical parameter testing, finished product storage.

Example 3

Step 1: Granulation: 300 kg of zinc oxide per batch, plus 58 kg of additives, planetary agitator ball milling for 5 hours and then spray granulation. The physical parameters of the granulated material: (1) Average particle size: 70 microns; (2) Bulk density: 1.55 g / cubic centimeter, (3) moisture content 1.8%; (4) solid content is 58%.

Bismuth oxide 5% in additives, cobalt oxide 3.5%, antimony oxide 6%, nickel oxide 0.1%, manganese oxide 1%, chromium oxide 0.6%, silicon dioxide 2%; The percentage by mass in the composition, i.e. its base is the additive and zinc oxide.

Step 2: Molding: Blank diameter: 80mm, weight 390g, pressing curve is 5 times of exhaust, exhaust time is 6 seconds, holding time is 20 seconds.

Step 3: Pre-burning: the pre-burning temperature is 700°C, and the holding time is 10 hours;

Step 4: Firing: maximum temperature 1115°C; holding time 12 hours;

Step 5: heat treatment: the maximum temperature is 600°C, and the holding time is 3 hours.

Step 6: Grinding, aluminum spraying, electrical parameter testing, finished product storage.

Example 4

Step 1: Granulation: 300 kg of zinc oxide per batch, plus 59 kg of additives, planetary agitator ball milling for 5 hours and then spray granulation. The physical parameters of the granulated material: (1) Average particle size: 70 microns; (2) Bulk density: 1.55 g / cubic centimeter, (3) moisture content 1.8%; (4) solid content is 63%.

Bismuth oxide 3% in additives, cobalt oxide 1.5%, antimony oxide 5%, nickel oxide 0.2%, manganese oxide 1.2%, chromium oxide 1.2%, silicon dioxide 3%; % by mass in the composition, i.e. its base is the additive and zinc oxide.

Step 2: Forming: Blank diameter: 80mm, weight 390g, pressing curve is 5 times of exhaust, exhaust time is 4 seconds, and pressure holding time is 12 seconds.

Step 3: Pre-burning: the pre-burning temperature is 800°C, and the holding time is 6 hours;

Step 4: Firing: maximum temperature 1200°C; holding time 10 hours;

Step 5: heat treatment: the maximum temperature is 650°C, and the holding time is 2.5 hours.

Step 6: Grinding, aluminum spraying, electrical parameter testing, finished product storage.

Example 5

Step 1: Granulation: 300 kg of zinc oxide per batch, plus 59 kg of additives, planetary agitator ball milling for 5 hours and then spray granulation. The physical parameters of the granulated material: (1) Average particle size: 70 microns; (2) Bulk density: 1.55 g / cubic centimeter, (3) moisture content 1.8%; (4) solid content is 62%.

Additives include 4% bismuth oxide, 1.5% cobalt oxide, 4% antimony oxide, 0.1% nickel oxide, 0.8% manganese oxide, 0.6% chromium oxide, and 1% silicon dioxide; The percentage by mass in the composition, i.e. its base is the additive and zinc oxide.

Step 2: Forming: Blank diameter: 80mm, weight 390g, pressing curve is 6 exhaust times, exhaust time is 5 seconds, and pressure holding time is 18 seconds.

Step 3: Pre-burning: the pre-burning temperature is 750°C, and the holding time is 7 hours;

Step 4: Firing: maximum temperature 1100°C; holding time 11 hours;

Step 5: heat treatment: the maximum temperature is 620°C, and the holding time is 2 hours.

Step 6: Grinding, aluminum spraying, electrical parameter testing, finished product storage.

Example 6

Step 1: Granulation: 300 kg of zinc oxide per batch, plus 59 kg of additives, planetary agitator ball milling for 5 hours and then spray granulation. The physical parameters of the granulated material: (1) Average particle size: 70 microns; (2) Bulk density: 1.55 g / cubic centimeter, (3) moisture content 1.8%; (4) solid content is 61%.

Additives include 3% bismuth oxide, 1.5% cobalt oxide, 4% antimony oxide, 0.1% nickel oxide, 0.8% manganese oxide, 0.6% chromium oxide, and 1% silicon dioxide; % by mass in the composition, i.e. its base is the additive and zinc oxide.

Step 2: Forming: Blank diameter: 80mm, weight 390g, pressing curve is 6 exhaust times, exhaust time is 5 seconds, and pressure holding time is 8 seconds.

Step 3: Pre-burning: the pre-burning temperature is 850°C, and the holding time is 8 hours;

Step 4: Firing: maximum temperature 1200°C; holding time 11 hours;

Step 5: heat treatment: the maximum temperature is 680°C, and the holding time is 3 hours.

Step 6: Grinding, aluminum spraying, electrical parameter testing, finished product storage.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (5)

1. A manufacturing method of a high-gradient resistor disc is characterized by comprising the following steps:

step 1, grinding and uniformly mixing bismuth oxide, cobalt oxide, antimony oxide, nickel oxide, manganese oxide, chromium oxide and silicon dioxide by a grinder to obtain an additive; by mass percent, the mass fraction of bismuth oxide is 3-5%, the mass fraction of cobalt oxide is 1.5-3.5%, the mass fraction of antimony oxide is 4-6%, the mass fraction of nickel oxide is 0.1-0.5%, the mass fraction of manganese oxide is 0.8-2.0%, the mass fraction of chromium oxide is 1-1.5%, and the mass fraction of silicon dioxide is 2-3%;

step 2, adding the additive and zinc oxide into a mixer, mixing uniformly, and then ball-milling in a ball mill to obtain granulated materials; the additive particles of the milled D50 were less than 0.4 μm; wherein the mass fraction of the zinc oxide is 82-89%, and the total mass of the zinc oxide and each substance in the step 1 is 100%;

step 3, pressing and molding the granulated material, performing air exhaust for a plurality of times in the molding process, and performing pressure maintaining molding once to obtain a process resistor disc;

step 4, sintering the process resistance card to obtain a sintered resistance card;

in step 4, sintering comprises pre-sintering, sintering and heat treatment;

the pre-sintering temperature is 700-950 ℃, and the pre-sintering time is 3-10 hours;

the sintering temperature is 1100-1200 ℃, and the sintering heat preservation time is not less than 10h;

the temperature of the heat treatment is 600-700 ℃, and the heat is preserved for 2-3 hours at the target temperature;

in the heat treatment process, the speed of raising the temperature from room temperature to the target heat treatment temperature is 150 ℃/h, and the cooling speed after the heat preservation target time is 80 ℃/h;

before heat treatment, coating a layer of lead-free glass glaze on the side surface of the fired resistor disc;

and 5, spraying an aluminum electrode on the surface of the sintered resistance card to obtain the high-gradient resistance card.

2. A method for manufacturing a high gradient resistor disc as described in claim 1, wherein in step 1, the grinding medium is zirconia beads with a diameter of 0.4-0.5 mm.

3. The method for manufacturing the high-gradient resistor disc as claimed in claim 1, wherein in the step 2, the solid content in the mixing machine is 58-63%.

4. The method for manufacturing a high gradient resistor disc as claimed in claim 1, wherein in step 3, each exhaust time is 4-6s, the dwell time is 8-20s, and the number of exhaust times is 5-7.

5. A high-gradient resistor sheet manufactured by the manufacturing method of any one of claims 1 to 4, wherein the thickness of the aluminum electrode on the surface of the resistor sheet is 0.07mm to 0.1mm, and the gradient of the resistor sheet is 300V/mm to 330V/mm.

Images