Properties and applications of thermally conductive ceramic gaskets

Thermally conductive ceramic gasket is a material with high thermal conductivity. It is mainly made of alumina (alumina content as high as 95%) or zirconia. It has a pure white appearance and a hard texture. It is mainly used between power devices and radiators. thermal and electrical isolation.

After it is tightly combined with power devices (such as power MOS tubes, power triodes, etc.), aluminum radiators, and PCB boards, it has excellent sealing performance, which can achieve the ideal effects of dustproof, waterproof, heat conduction, and insulation, and can adapt to high temperature and high pressure , Dusty harsh working environment, improve the safety and stability of equipment operation.

Performance characteristics of ceramic gaskets

Ceramic gaskets have the following characteristics:

The thermal conductivity of ceramic pads (20°C) is as high as 20 W/(m-K)~30W/(m-K), which is much higher than that of ordinary thermal pads, so it is widely used in the conditions of very demanding heat dissipation of power devices.

At present, the thermal conductivity of thermal pads is mostly below 2.0 W/(m-K), and the Beggs SIL-Pad2000 series with higher thermal conductivity is only 3.5W/(m-K);
Resistant to high temperature and high pressure. The breakdown strength of the ceramic gasket is 10kV~12kV, and the maximum allowable temperature is 1600°C. It can adapt to the harsh working environment of high temperature, high pressure, high wear and strong corrosion, and meet the application requirements of power supply products in various occasions;
Long service life.

It can reduce the maintenance times of equipment and improve the safety and stability of equipment operation;
Comply with EU RoHS environmental protection standard.

Ceramic Spacer Thermal Path

Ordinary thermal pads are composed of soft dielectric materials, which can fill the small gap between the power device and the surface of the heat sink to reduce its contact thermal resistance. The ceramic spacer is composed of hard alumina with a certain roughness on the surface. If it is assembled directly, there will be many gaps between the power device and the ceramic spacer, and between the radiator and the ceramic spacer, which will seriously affect the heat dissipation efficiency.

The performance of the radiator is greatly reduced, or even unable to play a role. Therefore, when using a ceramic gasket as a thermally conductive material, it is also necessary to apply thermally conductive silicone grease on both surfaces to fill the small gaps between the ceramic gasket and the heat sink, and between the ceramic gasket and the power device, and reduce them. The thermal contact resistance between them.

Compared with thermal pads, ceramic gaskets have the following defects (points to be paid attention to when selecting radiators)——the material of ceramic gaskets is hard, but brittle, and has poor resistance to bending deformation. case, it is fragile when installed.

The ceramic gasket is used as the heat conduction material between the power device and the radiator, which has high heat conduction efficiency, high temperature/high pressure resistance, uniform heating, fast heat dissipation, simple and compact structure, and has broad application prospects in high-power power supply products.

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