氧化铝填充导热凝胶的导热增强

Thermal conductivity enhancement of alumina-filled thermal conductive gel

为了缓解电子设备高集成化带来的元器件散热压力,该文制备了一种高导热、低渗油氧化铝填充导热凝胶,探究了填料复配、填料表面改性以及填料含量对氧化铝填充导热凝胶热导率、渗油率等性能的影响.研究表明,对于单一粒径氧化铝填充导热凝胶,填料的“适宜粒径”为20μm.粒径3μm与20μm的氧化铝按照质量比1∶7级配后制备的填充量为60%(体积分数)的导热凝胶热导率达到2.08 W·m^(-1)·K^(-1).对氧化铝进行硅烷偶联剂改性处理后,导热凝胶热导率提升27.2%,达到2.65 W·m^(-1)·K^(-1),热导率的提升与氧化铝表面氧原子的增多有关.导热凝胶的热导率随填料含量的增加先增大后减小,导热凝胶渗油率随填充量的增大而降低,氧化铝的“逾渗阈值”为60%.

To alleviate the heat dissipation pressure of components caused by high integration of electronic devices,an alumina-filled gel with high thermal conductivity and low oil penetration was prepared in this work.Specifically,the effects of filler compounding,surface modification and filler content on thermal conductivity and oil penetration were investigated.The results show that the appropriate size of the filler for thermal conductive gels filled with single-particulate alumina is 20μm.The thermal conductivity of the gel filled with 60%(volume fraction)of alumina was 2.08 W·m^(-1)·K^(-1),when the alumina particles of 3μm and 20μm were graded with the mass ratio of 1∶7.Moreover,the thermal conductivity of the gel filled with the alumina modified by silane coupling agent(2.65 W·m^(-1)·K^(-1))was increased by 27.2%.Our data indicated that the increase of oxygen atoms on the surface of alumina is crucial in enhancing the thermal conductivity of the gel.The thermal conductivity of the gel varies with filler content,increasing initially and then decreasing.While,the oil penetration rate of the gel decreases as the filling volume increases.The percolation threshold of alumina is 60%.