Extended Data Fig. 7: Oxidation and service stability of colloidal LMs.

a, R_eff results of the colloidal LM at different temperatures, ranging from 50 ^oC to 125 ^oC. b, Gallium oxide content in the colloidal LM after exposing it to different conditions for various durations. These conditions included direct exposure to an air environment at 80 ^oC, a high-temperature condition at 150 ^oC with the colloidal LM sandwiched at the thermal interface, and an 85–85 test condition at 85 ^oC and 85% relative humidity (RH) with the colloidal LM also sandwiched at the thermal interface. The results indicate that the nanoscale layer of gallium oxide outside the colloidal LM effectively prevents air penetration. Additionally, the sandwiched configuration helps the colloidal LM resist serious penetration of water humidity. c, High-temperature resistance of colloidal LMs by thermogravimetric analysis. d, Thermal stability of R_eff performance after exposing the colloidal LM to different conditions for various durations. These conditions included exposure to an air environment at 80 ^oC, a high-temperature condition at 150 ^oC, and an 85-85 test condition at 85 ^oC and 85% RH. e, Thermal cycling stability of R_eff performance after exposing colloidal LM and silicone grease to an alternating hot (80 ^oC) and cold scene (−20 ^oC). Herein, LM/AlN colloid with the addition of 42.5 vol% AlN (30 µm) was used as an example. The colloidal LM is sandwiched by two nickel plates, as shown in the inset image. These results suggest that when sandwiched at the thermal interface during service, the colloidal LMs are stable in air and high-temperature conditions. However, the thermal resistance will exhibit some slight increase when the colloidal LMs are exposed to high-humidity or cyclic heating and cooling conditions. In a, b, d, and e, the data points and error bars show the mean ± s.d. (sample size 3).