Innovative Technology Analysis of PTC Thermistor High Temperature Sintering Conductive Silver Paste

In the rapid development of electronic materials and components, PTC (Positive Temperature Coefficient) thermistor, as an important temperature sensor, has attracted increasing attention in terms of its performance and application. As a crucial step in the production process of PTC thermistors,High temperature sintered conductive silver pasteThe formula and preparation technology directly affect the performance and cost of the final product.

Technical background

PTC thermistor is a temperature sensitive component based on semiconductor materials, and its resistance value increases sharply with increasing temperature. In the manufacturing process, in order to ensure a good ohmic contact between the electrode layer and the ceramic body, a layer needs to be made on the surface of the PTC ceramicConductive silver paste electrode layerTraditional conductive silver paste has problems such as high silver content, high sintering temperature, narrow sintering range, and general adhesion, which limit its application range and cost-effectiveness.

Introduction to Innovative Technologies

Formula optimization

The PTC thermistor of the present invention uses high-temperature sintered conductive silver paste, and its formula has been carefully optimized, mainly including the following components and their weight content:

• Metallic silver powder: 55-72%, usingSpherical silver powderA mixture of flake silver powder with particle sizes of 0.5-1.5 μ m and 0.5-1.0 μ m, and tap densities of 1.5-2.5g/ml and 1.0-2.0g/ml, respectively. This combination effectively improves the density and conductivity of sintering, while reducing the silver content.
• Glass powder: 1-10%, usingLead free glass powderThe sintering temperature is between 490-700 ° C, and its components include Bi ₂ O3, SiO ₂, ZnO, TiO ₂, SrO, and Al ₂ O3, which effectively enhance the adhesion between the silver layer and the ceramic substrate and broaden the sintering temperature range.
• Organic carrier: 20-45%, containing polymer resins (such as ethyl cellulose, nitrocellulose, rosin, etc.) and organic solvents (such as butyl ether, ethylene glycol ether, turpentine, etc.), which play a role in dispersing, suspending and adjusting viscosity, ensuring good printing performance and long-term stability of the slurry.
• Solvent: 1-15%, used to adjust the viscosity and flowability of the slurry, ensuring the uniformity and stability of the slurry during the preparation process.

Preparation process

The preparation process of the present invention mainly includes the following steps:

1. Preparation of organic carrier: Heat the polymer resin and organic solvent to 80 ° C and maintain a constant temperature until the resin is completely dissolved. Filter out impurities to obtain the organic carrier.
2. Preparation: Accurately weigh metal silver powder, glass powder, organic carrier, and solvent according to the above formula.
3. Preparation of silver paste: Metal silver powder and glass powder are thoroughly mixed with organic carriers and solvents in a mixing machine, and then dispersed at high speed using a high-speed disperser to obtain a uniform paste.
4. Production of silver paste: The paste is ground on a three roll grinder, and the fineness of the silver paste is controlled below 10 μ m and the viscosity is 30-50Pa. s through fine adjustment of the rollers, resulting in high-quality silver pasteConductive silver paste.

Technical advantages

1. Low cost: By optimizing the ratio of silver powder and glass powder, the silver content has been reduced, significantly reducing material costs.
2. Low sintering temperature and wide sintering range: By using a specific ratio of glass powder, the sintering temperature is lowered to 490 ° C, and the sintering range is wide up to 490-700 ° C, which improves production efficiency and reduces energy consumption.
3. Strong adhesion: SrO and TiO ₂ in the glass powder melt together with the ceramic matrix during the sintering process, forming a new homogeneous phase state, significantly enhancing the adhesion of the silver layer.
4. Excellent performance: The fineness and viscosity of the conductive silver paste are properly controlled, ensuring the uniformity and density of the electrode layer, and improving the overall performance of the PTC thermistor.

application prospect

PTC ThermistorWidely used in various fields such as light industry, housing, transportation, aerospace, agriculture, healthcare, environmental protection, etc. With the advancement of technology and the development of industries, the performance requirements for PTC thermistors are becoming increasingly high. The high-temperature sintered conductive silver paste technology used in the PTC thermistor of the present invention, with its advantages of low cost, low sintering temperature, wide sintering range, and strong adhesion, will undoubtedly promote the further development of the PTC thermistor industry and provide strong support for technological innovation and industrial upgrading in related fields.

conclusion

In summary, the PTC thermistor of the present invention utilizes high-temperature sintered conductive silver paste technology, which achieves significant technological innovation and performance improvement through optimized formulation and preparation process. This technology not only reduces production costs and improves production efficiency, but also enhances the market competitiveness of the product, laying a solid foundation for the widespread application of PTC thermistors. In the future, with the continuous improvement of technology and the deepening of its promotion and application, this technology is expected to demonstrate its unique value and charm in more fields.