Sodium silicate based thermal interface material for high thermal contact conductance

Sodium silicate based thermal interface pastes give higher thermal contact conductance across conductor surfaces than polymer based pastes and oils, d ue to their higher fluidity and the consequent greater conformability. Addi tion of hexagonal boron nitride particles up to 16.0 vol. percent further i ncreases the conductance of sodium silicate, due to the higher thermal cond uctivity of BN. However, addition beyond 16.0 vol. percent BN causes the co nductance to decrease, due to the decrease in fluidity. At 16.0 vol. percen t BN, the conductance is up to 63 percent higher than those given by silico ne based pastes and is almost as high as that given by solder. Water is alm ost as effective as sodium silicate without filler, but the thermal contact conductance decreases with time due to the evaporation of water. Mineral o il and silicone without filler are much less effective than water or sodium silicate without filler.