Preparation And Properties Of The Thermal Interface Composite Materials Of Diamond-silicone Rubber

With the increase of integration of electronic components, it is going to exacerbate the thermal trouble. So how to ensure effective heat dissipation and the long-time stable operation of electronic components becomes an urgent problem. Elastic thermal interface materials with good deformation properties and low thermal resistance, can be filled between electronic components and the heat sink to expel the air and quicken the heat dissipation Therefore, it is very important to prepare a thermal interface material with high thermal conductivity.This paper prepares diamond fiber on a tungsten substrate by MPCVD. The diamond fiber and diamond particle are added into the silicone rubber to prepare diamond- silicone rubber composite. The morphology, thermal conductivity, mechanical properties, thermal stability, thermal expansion coefficient were characterized by scanning electron microscope(SEM), Raman spectroscopy,X-ray diffraction((XRD), thermal analyzer, mechanical tests, thermal gravimetric analysis(TG), thermal mechanical analyzer(TMA), etc. Then the effects growth temperature, methane concentration, the growth time and other parameters on the diamond fiber quality, as well as the filler content, particle size, combined distribution were discussed detailed.The research showed that only when the growth temperature and methane concentration were moderate could diamond fiber be in high quality. The diamond growth time mainly affected the diameter of the fiber. The growth temperature of 900 ℃, the methane concentration of 4%,were the optimal parameters.With the increase of the content, the thermal conductivity of the composite increased at first and then decreased. When filling mass fraction of diamond particles was 70%, the thermal conductivity of the silicone rubber composites reached the maximum of 1.064W/(m?K), but the mechanical properties decreased. With the increase of the filler size, the thermal conductivity of the silicone rubber rose in general and reached its maximum at the size of 40μm and the hardness decreased. When filled with different size of diamond filler, the thermal conductivity was improved. When the content of the smaller diamond particle of 5μm was 40%, the thermal conductivity reached its maximum of1.364W/(m?K), and the mechanical properties were preferred. When the diamond fiber were added into the matrix with diamond particle, the thermal conductivity could be improved.