Thermally conductive silicone grease is a chemical substance, so it also has performance parameters that reflect its own operating characteristics. By understanding the meaning of these parameters, we can judge the performance of a thermally conductive material.
 

1、Heat conduction coefficient

The thermal conductivity of the heat transfer coefficient of silicone grease is basically the same as that of heat sink, and its unit is W/mK, that is, the heat transfer power when the temperature difference of 1 meter distance along the axial direction of the column with a cross-sectional area of 1 square meter is 1 Kelvin (1K = 1 ℃). The larger the value, the faster the heat transfer rate of the material and the better the thermal conductivity. At present, the heat conduction coefficient of mainstream thermally conductive silicone grease is greater than 1.134W/mK.

2、Working temperature

 The working temperature is an important parameter to ensure the thermal conductive material is in solid or liquid state. If the temperature is too high, the thermal conductive material will become liquid due to **; if the temperature is too low, it will become solid due to the increase of viscosity, both of which are not conducive to heat dissipation. The working temperature of thermal conductive silicone grease is generally from -50℃ to 220℃. We don't need to worry about the working temperature of thermal conductive silicone grease, after all, it is difficult to exceed this range of CPU temperature by conventional means.

 3、Thermal resistance coefficient

 Thermal resistance coefficient indicates the effect of the object on heat conduction obstruction. The concept of thermal resistance is very similar to that of resistance, and the unit is also similar to it (℃/W), that is, the temperature difference between the two ends of the thermal conductivity path when the object continues to transfer heat power of 1W. Thermal resistance is obviously the lower the better, because the lower the thermal resistance, the lower the temperature of the heat generating object at the same ambient temperature and thermal conductivity power. The size of thermal resistance has a lot to do with the material used in thermal conductive silicone grease.

 4、Dielectric constant

 For some CPUs that are not protected by metal top cover, the dielectric constant is a very important parameter, which is related to whether there is a short circuit inside the computer. The ordinary thermal grease used is a good insulating material, but some special silicone grease (such as silver silicone grease, etc.) may have a certain degree of conductivity. Many CPUs are now equipped with a metal top cover for thermal conductivity and protection of the core, so there is no need to worry about short circuit problems caused by the overflow of thermal grease. At present, the dielectric constant of thermal grease used in mainstream heat sinks is greater than 5.1.

 5、Viscosity

 Viscosity is the viscosity of the thermal grease. Generally speaking, the viscosity of thermal grease is around 68.

 6、Insulation

Thermally conductive silicone grease is a kind of high thermally conductive insulating silicone material, which almost never cures and can be kept in the grease state when used for a long time under the temperature of -50℃ to +230℃. It has both excellent electrical insulation and excellent thermal conductivity, as well as low free degree (tends to zero), high and low temperature resistance, water resistance, ozone resistance, and weather aging resistance. It can be widely coated in a variety of electronic products, electrical equipment, heat generators (power tubes, silicon, electric heat stack, etc.) and heat dissipation facilities (heat sink, heat sink, shell, etc.) between the contact surface, the role of heat transfer medium and moisture, dust, corrosion, shock resistance and other properties. Suitable for microwave communication, microwave transmission equipment, microwave special power supply, voltage stabilization power supply, etc. surface coating or overall potting of various microwave devices, such silicon materials for heat-generating electronic components, providing excellent thermal conductivity. Such as: transistors, CPU assembly, thermistors, temperature sensors, automotive electronic parts, automotive refrigerators, power supply modules, printer heads, etc.