Preparation And Characterization Of H-BN Filled Sodium Silicate Matrix Thermal Conductive Adhesive

Due to the increase of power density and miniaturization of microelectronics, heatdissipation has become one of the many factors that greatly influence the performanceand reliability of electronic products. Thermal conductive adhesive with micro-sizedhexagonal boron nitride as filler and sodium silicate with modulus of3.2as matrix wasprepared in this thesis. The loading amount of BN was increased to above70wt%byadjusting the concentration of sodium silicate. SEM, FTIR and DTA were used tocharacterize the composition and solidification process of TCA. The thermalconductivity of TCA with different components was determined with Laser FlashMethod and influence of BN content, BN size, BN hydrolysis and pressure on it wasanalyzed. The adhesive strength and breakdown strength of TCA with differentcomponents were tested respectively in dry and70%moisture environment.The experimental results indicate good combination between BN and sodiumsilicate matrix and thus homogeneous and stable mixture can be obtained. The thermalconductivity of TCA increases with increasing size of BN; the BN hydrolysis inducedby heating during preparation will improve the thermal conductively slightly. Itindicates that BN particles will overlap with each other due to percolation when BNcontent is above30wt%and thus the thermal conductivity increases rapidly with theincreasing of BN content; the thermal conductivity of9W/m·K can be obtained withBN content of70wt%. Proper amount of BN significantly improve the adhesivestrength of TCA; the adhesive strength of TCA with50wt%BN can exceed40MPa oncondition of dehydration. The breakdown strength decreases with the increasing ofthickness of TCA in consequence of thermal breakdown; increasing the concentration ofBN results in the improvement of breakdown strength and3kV/mm can be obtain fordry TCA with BN content of70wt%. Above all, sodium silicate matrix h-BN filledthermal conductivity has broad application prospects on account of its thermaldissipating performance, adhesive strength and insulating property.