金刚石微粉含量对硅酸钠基导热胶粘接和导热性能的影响

Effect of diamond powder content on bonding and thermal conductivity of sodium silicate based thermal conductive adhesive

为找到导热胶粘接和导热综合性能最佳时的金刚石微粉含量范围,以金刚石微粉含量为变量,研究其对导热胶性能的影响。用硅烷偶联剂对所用不同粒径的金刚石微粉表面进行改性,其中对粒径为60μm的金刚石微粉先单独进行表面刻蚀处理以增大其比表面积,再将粒径分别为60、20和10μm的金刚石微粉按质量比为6∶2∶1的配比做填料、水玻璃做基体,制备一种新型无机导热胶。结果表明:同时,导热胶的粘接性能先升高后降低,在金刚石质量分数为60%时粘接性能最佳,拉伸剪切强度为1.98 MPa;随着金刚石含量增加,导热胶的导热性能先升高后降低,当金刚石质量分数为50%时导热性能最佳,导热系数为6.32 W/(m·K)。因而当金刚石质量分数为50%~60%时,导热胶的粘接性能和导热性能最佳。

In order to find out the best range of diamond powder content for heat conductive adhesive,the influence of diamond powder content on the heat conductive adhesive was studied.The surface of diamond powder with different particle sizes was modified by silane coupling agent.In order to increase the specific surface area of diamond powder,a new type of inorganic thermal conductive adhesive was prepared by using 60μm,20μm and 10μm diamond powder as filler and water glass as matrix at the mass ratio of 6∶2∶1.The results show that the adhesive property of thermal conductive adhesive increases at first and then decreases,and that the adhesive property is best when the content of diamond is 60%and the tensile shear strength is 1.98 MPA.Besides,the thermal conductivity of the adhesive increases first and then decreases.The best thermal conductivity is 6.32 W/(m·K)when the content of diamond is 50%.Therefore,when the mass fraction of diamond is 50%~60%,the adhesive and thermal conductivity of thermal conductive adhesive is the best.