Investigation on the Optimized Binary and Ternary Gallium Alloy as Thermal Interface Materials

Abstract

This work presents an experimental study to enhance the thermal contact conductance of high performance thermal interface materials (TIMs) using gallium alloy. In this experiment, the gallium alloy-based TIMs are synthesized by a micro-oxidation reaction method, which consists of gallium oxides (Ga2O3) dispersed uniformly in gallium alloys. An experimental apparatus is designed to measure the thermal resistance across the gallium alloy-based TIMs under steady-state conditions. The existence of Ga2O3 can effectively improve the wettability of gallium alloys with other materials. For example, they have a better wettability with copper and anodic coloring 6063 aluminum-alloy without any extrusion between the interface layers. Gallium binary alloy-based TIMs (GBTIM) or ternary alloy based-TIMs (GTTIM) are found to increase the operational temperature range comparing with that of the conventional thermal greases. The measured highest thermal conductivity is as high as 19.2 Wm−1K−1 for GBTIM at room temperature. The wide operational temperature, better wettability, and higher thermal conductivity make gallium alloy-based TIMs promising for a wider application as TIMs in electronic packaging areas. The measured resistance is found to be as low as 2.2 mm2 KW−1 for GBTIM with a pressure of 0.05 MPa, which is much lower than that of the best commercialized thermal greases. In view of controlling pollution and raw materials wasting, the gallium alloy-based TIMs can be cleaned by 30% NaOH solution, and the pure gallium alloys are recycled, which can satisfy industrial production requirements effectively.