Preparation method of high-nonlinearity pressure-sensitive ceramic

Abstract

The invention relates to a preparation method of a high-nonlinearity pressure-sensitive ceramic, and belongs to the technical field of pressure-sensitive ceramic. Silicon dioxide-magnesium oxide-stannic oxide composite aerogel prepared by a sol-gel method is used as a filler; zinc oxide and bismuth oxide are used as raw materials, and the raw materials are compounded with polyurethane rubber to prepare the high-nonlinearity pressure-sensitive ceramic. Aerogel is a novel light nano-porous amorphous solid material with a controllable structure, due to the specific nano-porous and three-dimensional network structure of aerogel, aerogel has a plurality of unique properties, such as high porosity, low density, low thermal conductivity and the like; due to the fact that a quantum dot structure is formed in a nano network of silicon dioxide aerogel, magnesium oxide and stannic oxide are doped through a synchronous sol-gel method, the nonlinear coefficient of the pressure-sensitive ceramic canbe effectively increased; and due to doping of magnesium oxide, the prepared pressure-sensitive ceramic has good electrical properties such as residual voltage ratio, nonlinear coefficient and voltage gradient.

Description

technical field

[0001] The invention relates to a preparation method of highly nonlinear pressure-sensitive ceramics, belonging to the technical field of pressure-sensitive ceramics. Background technique

[0002] The pressure-sensitive characteristic refers to a phenomenon that when the voltage applied to the pressure-sensitive material exceeds a certain critical value, the current through the pressure-sensitive material increases rapidly, and the resistivity drops sharply; It can well protect the electrical components from damage. When the voltage is normal or lower than the varistor voltage of the varistor material, the varistor ceramic is regarded as an insulator, and the resistance value is very high. However, when the operating voltage is higher than the varistor voltage of the varistor due to an unexpected situation, the resistance of the varistor immediately decreases and approaches the conductor, and it appears that the branch circuit of the electrical device has a ...

Examples

Embodiment 1

[0035] Mix citric acid and 20% tin tetrachloride solution at a mass ratio of 1:6, and stir at a temperature of 40°C and a stirring speed of 400r / min for 15 minutes to obtain a reaction solution, at a mass ratio of 1:12 Add 0.5 mol / L ammonia water dropwise to the reaction solution, continue to stir for 1 hour, filter to obtain the precipitate after natural cooling, wash the precipitate with deionized water 3 times to obtain the reactant, heat the reactant to a temperature of 40°C, and use Saturated oxalic acid solution adjusted the pH value of the system to 1.5 to obtain sol A; heated and melted the stearic acid ester at 80°C for 5 minutes to obtain a melt, and mixed magnesium nitrate and the melt at a mass ratio of 1:4, and then Continue stirring at a constant temperature for 15 minutes at a stirring speed of 200r / min to obtain sol B; mix silica sol, sol A and sol B at a mass ratio of 2:1:1, and stir at a temperature of 60°C and a stirring speed of 300r / min Gel for 1 hour to o...

Embodiment 2

[0037] Mix citric acid with a mass fraction of 20% tin tetrachloride solution at a mass ratio of 1:6, and stir at a constant temperature for 18 minutes at a temperature of 55°C and a stirring speed of 450r / min to obtain a reaction solution, at a mass ratio of 1:12 Add 0.5 mol / L ammonia water dropwise to the reaction solution, continue to stir for 1 hour, filter the precipitate after natural cooling, wash the precipitate 4 times with deionized water to obtain the reactant, heat the reactant to a temperature of 55°C, and use Saturated oxalic acid solution adjusted the pH value of the system to 1.8 to obtain sol A; heated and melted the stearic acid ester at a temperature of 5°C for 8 minutes to obtain a melt, and mixed magnesium nitrate and the melt at a mass ratio of 1:4, and then Continue stirring at a constant temperature for 18 minutes at a stirring speed of 250r / min to obtain sol B; mix silica sol, sol A and sol B at a mass ratio of 2:1:1, and stir at a temperature of 65°C a...

Embodiment 3

[0039] According to the mass ratio of 1:6, mix citric acid with a mass fraction of 20% tin tetrachloride solution, and stir at a temperature of 70°C and a stirring speed of 500r / min for 20 minutes to obtain a reaction solution, according to a mass ratio of 1:12 Add 0.5 mol / L ammonia water dropwise to the reaction solution, continue to stir for 2 hours, filter to obtain the precipitate after natural cooling, wash the precipitate with deionized water 5 times to obtain the reactant, heat the reactant to a temperature of 70°C, and use Saturated oxalic acid solution adjusted the pH value of the system to 2.0 to obtain sol A; heated and melted the stearic acid ester at a temperature of 90°C for 10 minutes to obtain a melt, and mixed magnesium nitrate and the melt at a mass ratio of 1:4, and then Continue to stir at a constant temperature for 20 minutes at a stirring speed of 300r / min to obtain sol B; mix silica sol, sol A and sol B at a mass ratio of 2:1:1, and stir at a temperature ...

technical field

[0001] The invention relates to a preparation method of highly nonlinear pressure-sensitive ceramics, belonging to the technical field of pressure-sensitive ceramics. Background technique

[0002] The pressure-sensitive characteristic refers to a phenomenon that when the voltage applied to the pressure-sensitive material exceeds a certain critical value, the current through the pressure-sensitive material increases rapidly, and the resistivity drops sharply; It can well protect the electrical components from damage. When the voltage is normal or lower than the varistor voltage of the varistor material, the varistor ceramic is regarded as an insulator, and the resistance value is very high. However, when the operating voltage is higher than the varistor voltage of the varistor due to an unexpected situation, the resistance of the varistor immediately decreases and approaches the conductor, and it appears that the branch circuit of the electrical device has a ...

Examples

Embodiment 1

[0035] Mix citric acid and 20% tin tetrachloride solution at a mass ratio of 1:6, and stir at a temperature of 40°C and a stirring speed of 400r / min for 15 minutes to obtain a reaction solution, at a mass ratio of 1:12 Add 0.5 mol / L ammonia water dropwise to the reaction solution, continue to stir for 1 hour, filter to obtain the precipitate after natural cooling, wash the precipitate with deionized water 3 times to obtain the reactant, heat the reactant to a temperature of 40°C, and use Saturated oxalic acid solution adjusted the pH value of the system to 1.5 to obtain sol A; heated and melted the stearic acid ester at 80°C for 5 minutes to obtain a melt, and mixed magnesium nitrate and the melt at a mass ratio of 1:4, and then Continue stirring at a constant temperature for 15 minutes at a stirring speed of 200r / min to obtain sol B; mix silica sol, sol A and sol B at a mass ratio of 2:1:1, and stir at a temperature of 60°C and a stirring speed of 300r / min Gel for 1 hour to o...

Embodiment 2

[0037] Mix citric acid with a mass fraction of 20% tin tetrachloride solution at a mass ratio of 1:6, and stir at a constant temperature for 18 minutes at a temperature of 55°C and a stirring speed of 450r / min to obtain a reaction solution, at a mass ratio of 1:12 Add 0.5 mol / L ammonia water dropwise to the reaction solution, continue to stir for 1 hour, filter the precipitate after natural cooling, wash the precipitate 4 times with deionized water to obtain the reactant, heat the reactant to a temperature of 55°C, and use Saturated oxalic acid solution adjusted the pH value of the system to 1.8 to obtain sol A; heated and melted the stearic acid ester at a temperature of 5°C for 8 minutes to obtain a melt, and mixed magnesium nitrate and the melt at a mass ratio of 1:4, and then Continue stirring at a constant temperature for 18 minutes at a stirring speed of 250r / min to obtain sol B; mix silica sol, sol A and sol B at a mass ratio of 2:1:1, and stir at a temperature of 65°C a...

Embodiment 3

[0039] According to the mass ratio of 1:6, mix citric acid with a mass fraction of 20% tin tetrachloride solution, and stir at a temperature of 70°C and a stirring speed of 500r / min for 20 minutes to obtain a reaction solution, according to a mass ratio of 1:12 Add 0.5 mol / L ammonia water dropwise to the reaction solution, continue to stir for 2 hours, filter to obtain the precipitate after natural cooling, wash the precipitate with deionized water 5 times to obtain the reactant, heat the reactant to a temperature of 70°C, and use Saturated oxalic acid solution adjusted the pH value of the system to 2.0 to obtain sol A; heated and melted the stearic acid ester at a temperature of 90°C for 10 minutes to obtain a melt, and mixed magnesium nitrate and the melt at a mass ratio of 1:4, and then Continue to stir at a constant temperature for 20 minutes at a stirring speed of 300r / min to obtain sol B; mix silica sol, sol A and sol B at a mass ratio of 2:1:1, and stir at a temperature ...