Ways to Improve the Performance of Thermally Conductive Silicone Grease

In thermal management applications, even two flat surfaces with very smooth surfaces can have voids when in contact with each other. The air in the void is a poor conductor of heat and prevents the conduction of heat to the heatsink. Thermally conductive silicone grease is a material that can fill these gaps and make heat conduction smoother and faster. In the preparation of thermally conductive silicone grease, the heat dissipation of the product can be improved in the following ways.

Controlling the Ratio of Thermally Conductive Fillers

The viscosity of the silicone grease can be controlled by using a suitable mix of small, medium, and large particle sizes of fillers, and the filler volume can be increased to improve the thermal conductivity. This is because a variety of particle size compounding can make the large and small particle size thermal conductive filler more closely stacked to form more thermal conductivity pathway. And small particle size filling in the gap between the large particle size can realize a higher filling ratio, the formation of a more compact stack. In addition, the addition of small particle size filler can also fill the gap between the thermal conductive filler, which can not only reduce the thermal resistance of thermally conductive silicone grease, but also reduce the tendency of silicone oil to creep, so that the oil permeation rate of thermally conductive silicone grease is lower.


Jamming refers to the screening of fillers by means of sieving to remove large filler sizes and to control the maximum particle size. The particle size distribution of the filler can be well controlled by jamming the filler. When the filler with concentrated particle size and narrow distribution is used for compounding, it is easier to fill the gap of filler and realize the grading effect of different particle sizes. This creates a good thermal conductivity pathway and reduces the contact thermal resistance, resulting in a thermally conductive silicone grease with a lower thermal resistance.

Control of Silicone Oil Viscosity

Compounding with 100 mPa-s polydimethylsiloxane at a viscosity of 500 mPa-s can reduce the oil penetration rate of the silicone grease under the premise of high filler and low viscosity. It also helps to reduce or avoid the occurrence of oil-powder phase separation. In addition, by enhancing the addition amount of small particle size powder to reduce the interfacial thermal resistance of silicone grease, it can also effectively improve its thermal conductivity and oil penetration performance. Not only can we obtain thixotropic thermally conductive silicone grease with ultra-low thermal resistance, but we can also utilize its rheological properties to enhance the sagging crack resistance and aging resistance of thermally conductive silicone grease.

Kneading Temperature

By adopting suitable kneading temperature and time, we can ensure that the filler is firmly coated by silane coupling agent and realize stable and uniform modification of powder. This not only reduces the viscosity of the system, but also achieves good gap filling between the fillers, resulting in thermally conductive silicone grease with excellent thermal conductivity and printing properties.

Nanjing Silfluo New Material Co., Ltd. (Silfluo) is located in Nanjing. Our silicone series silanes, silicone fluids, silicone resins, silicone rubbers, silicone additives, organophosphorus flame retardants and electronic chemicals are widely used in power communications, rail transit and automobiles, aerospace, national defense, medical health, new energy Materials, consumer electronics, agriculture and other fields. No matter what your needs are, we can provide you with satisfactory service.

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