Effects of Spherical Alumina and Hydrogen Silicone Oil on the Properties of Thermal Conductive Silicone Encapsulant.

A two-component thermal conductive silicone encapsulant was prepared by end-vinyl silicone oil, spherical alumina, platinum catalyst and hydrogen silicone oil. The effects of the mass ratio and particle size of spherical alumina and the a-mount of hydrogen silicone oil on the properties of the silicone encapsulant were studied. The results show that when the spherical alumina with average particle size 45 µm and 5 µm is used as thermal conductive filler, silicone encapsulant increases the thermal conductivity first and then decreases with the increase of spherical alumina with smaller particle size (5 µm). When the mass fraction of 5 µm spherical alumina in the thermal conductive filler is 40%, the thermal conductivity of silicone encapsulant reaches the maximum of 1.63 W/(m·K). The mass ratio of large and small spherical alumina is 6:4, the thermal conductivity and Shore A hardness of silicone encapsulant increases with the decrease of small size spherical alumina, and the thermal conductivity of silicone encapsulant increases with the increase of large size spherical alumina. With the increase of hydrogen silicone oil, the silicone encapsulant shortens its operable time and tends to be stable, and Shore A hardness is increased and becomes stable. [ABSTRACT FROM AUTHOR]