The difference between thermal grease and thermal silica

Thermal silica

Thermally Conductive Silica Gel is a one-component dealcoholized room temperature curable silicone rubber with cooling and bonding properties for electronic devices. It can be cured into a higher hardness elastomer in a short time. After curing, it closely adheres to the contact surface to reduce the thermal resistance, thereby facilitating heat conduction between the heat source and the heat sink, the main board, the metal shell and the outer casing. It has the advantages of high thermal conductivity, good insulation performance and easy to use. It has good adhesion to metals including copper, aluminum and stainless steel. The curing form is de-alcoholic, and it does not corrode metal and non-metal surfaces. It is much lower than thermal grease, and once cured, it is difficult to separate the bonded objects. Generally, it can only be used in graphics cards and memory heat sinks. If it is used on the CPU, it will cause overheating, and it is difficult to remove the heat sink. Pulling it down may directly damage the CPU or CPU socket. If you pull down the silicone-bonded graphics card heatsink, it is possible to unplug the display chip from the PCB.

Thermal Grease

Thermal grease, also known as silicone paste, is a grease-like, non-adhesive property that does not dry out. It is produced in a special formulation and is compounded with a metal oxide that is excellent in thermal conductivity and insulation. Made. The product has excellent thermal conductivity, good electrical insulation, wide operating temperature (operating temperature -60 ° C ~ 300 ° C), good stability of use, low consistency and good construction performance, this product has no Toxic, non-corrosive, odorless, not dry, insoluble. Silicone grease is used for lubrication and can be applied under high load. It looks like big butter. We generally have less contact. What we usually call thermal grease, it should be called silicone paste, the composition is silicone oil + filler. The filler is a finely ground powder with a composition of ZnO/Al2O3/boron nitride/silicon carbide/aluminum powder. Silicone oil guarantees a certain fluidity, and the filler fills a small gap between the CPU and the heat sink to ensure thermal conductivity. However, since silicone oil has low sensitivity to temperature, the low temperature does not become thick, it does not become thin at high temperatures, and it does not volatilize, so it can be used for a long time. Some high-grade thermal greases now use silver powder or aluminum powder as a filler, which utilizes the high thermal conductivity of the metal.

Although silicone grease and silica gel are only literally one word in length, and they are all heat-conducting materials, they are completely different things. Relatively speaking, silicone grease has a wider range of applications and is suitable for almost any heat-dissipating condition. Since silicone is difficult to remove once it is stuck, it is often used in applications where only one-time bonding is required. The heat sink of the graphics card, etc. If you need to know more about adhesives, please feel free to contact us or visit Xinwei's official website.

In heat and heat transfer applications, even if the two surfaces with very smooth surfaces come into contact with each other, voids appear. The air in these gaps is a poor conductor of heat, which hinders the conduction of heat to the heat sink. Thermal grease is a material that fills these gaps and makes heat transfer smoother and faster. There are many types of silicone greases on the market today, and different parameters and physical properties determine different uses. For example, some are suitable for CPU heat conduction, some are suitable for memory heat conduction, and some are suitable for power supply heat conduction.