制备了以碳纳米管(CNTs)和镀银碳纳米管(SCCNTs)为导电填料的各向同性导电胶,研究了它们的电学性能、力学性能及抗老化性能,并与传统的以微米量级的银粒子作为导电填料的导电胶的性能进行比较。研究发现:CNTs作为导电填料时,在填料体积分数为31%时出现体积电阻率的最低值2.4×10^-3 Ω.com在填料体积分数为23%时导电胶表现出最好的抗剪切性能。在填料体积分数同为28%时,填充SCCNTs导电胶具有最低的体积电阻率2.2×10^-3 Ω.com填充CNTs和SCCNTs显示出比填充微米量级银粒子导电胶高的抗剪切强度(19.6MPa)。在85℃、RH85%环境下经过1000h老化测试结果表明:填充SCCNTs或CNTs导电胶体积电阻率的变化和剪切强度的变化均不超过10%;而填充微米量级银粒子导电胶在老化后体积电阻率的变化和抗剪切强度的变化分别达到350%和120%。
Two kinds of isotropical conductive adhesives (ICA) were developed by using carbon nanotubes (CNTs) and silver coated carbon nanotubes (SCCNTs) as conductive fillers. The electrical, mechanical and aging properties of the above ICAs were investigated and compared with those of conventional ICA filled with l~tm average-sized Ag particles. The results indicated that the percolation threshold of bulk resistivity reaches 2.4×10^-3 Ω.com for ICA with 31% filler content of CNTs and the shear strength of ICA with 23% filler content of CNTs approaches the maximum value. At the same filler content of 28%, the ICAs filled with SCCNTs show the lowest conductive resistivity of 2.2 ×10^-3 Ω.com and the ICAs filled with both CNTs and SCCNTs exhibit higher shear strength of 19. 6 MPa. The results of aging properties tested under the conditions of 85℃, RH85% for 1000h showed that the shifts of both bulk resistivity and shear strength do not exceed 10% for the ICAs filled with both CNTs and SCCNTs, while the shifts of conductive resistivity and shear strength are 350% and 120%, respectively, for ICA filled with micro-sized Ag particles.