High-thermal-expansion-coefficient thick-film dielectric paste for stainless steel base material and preparation method thereof

Abstract

The invention relates to high-thermal-expansion-coefficient thick-film dielectric paste for a stainless steel base material and a preparation method thereof. The thick-film dielectric paste is characterized by comprising the following components in percentage by weight: 70-80% of lead-free microcrystalline glass powder and 20-30% of an organic bonding phase. The lead-free microcrystalline glass powder is BaO-CaO-Al2O3-SiO2-B2O3-SrO-Sm2O3-ZrO2 series microcrystalline glass powder, and the lead-free microcrystalline glass powder comprises the following components in percentage by weight: 10%-20%of BaO, 10%-15% of CaO, 5%-10% of Al2O3, 20%-30% of SiO2, 5%-20% of B2O3, 5%-10% of SrO, 5%-10% of Sm2O3 and 1%-6% of ZrO2. And the organic bonding phase comprises the following components in percentage by weight: 70%-85% of an organic solvent, 2%-10% of a polymer thickener, 0.5%-5% of a dispersing agent, 0.5%-5% of a leveling agent, 0.5%-5% of a thixotropic agent and 0.5%-5% of a surfactant. Thehigh-thermal-expansion-coefficient thick-film dielectric paste for the stainless steel base material has the characteristics of high uniformity, high stability, high solid content and the like.

Description

technical field [0001] The invention relates to the field of thick-film electronic paste, in particular to a thick-film medium paste with a high thermal expansion coefficient for stainless steel substrates and a preparation method thereof. Background technique [0002] High-power thick-film circuit elements and thick-film heating elements have the characteristics of high power density, high mechanical strength, thermal shock resistance, and vibration resistance, and put forward corresponding mechanical and thermal performance requirements for the substrate; the stainless steel substrate has good mechanical properties and high mechanical strength. , good impact resistance and other characteristics, so it is widely used in the preparation of high-power thick-film circuit components and high-power thick-film heating elements. At present, dielectric pastes for thick-film circuit elements and thick-film electric heating elements based on 1Cr17 stainless steel substrates are matur...

AI Technical Summary

Problems solved by technology

At present, dielectric pastes for thick-film circuit elements and thick-film electric heating elements based on 1Cr17 stainless steel substrates are mature and commercialized. However, the thermal expansion coefficient of existing dielectric pastes is low (about 7~8×10 -6 / °C), much lower than the thermal expansion coefficient of 1Cr17 stainless steel substrate (10.6×10 -6 / °C); the direct result of the mismatch of thermal expansion coefficients is that the thermal expansion and contraction of the substrate and the dielectric layer are not synchronized, resulting in a large thermal stress between the dielectric layer and the substrate, and the excessive thermal stress causes serious deformation of the substrate. Cause the dielectric layer to crack or even peel off from the substrate surface

[0003] When the existing thick-film dielectric slurry is applied to ultra-thin (thickness less than 0.8mm) stainless steel substrates, there is serious warping or deformation of the stainless steel substrate due to the thermal expansion coefficient mismatch between the dielectric slurry and the stainless steel substrate. It is impossible to continue to print defects such as conductor layers and resistance layers, which reduces the application range and reliability of thick film circuit elements and thick film heating elements; at the same time, the existing thick film dielectric paste is applied to thicker (thicker than 3.0mm ) stainless steel substrate, there are microcracks and defects formed in the insulating dielectric layer during the cooling process caused by the mismatch between the thermal expansion coefficient of the dielectric slurry and the stainless steel substrate, and the generation of these microcracks and defects provides channels for the movement of electrons , leading to low breakdown voltage and low insulation resistance of the dielectric layer, and it is easy to be broken down during use, and even lead to short circuit and other phenomena.