硼硅酸凝胶包覆层对铜粉抗氧化性和导电性的影响

铜电子浆料作为银电子浆料最为理想的替代材料,其越来越受到人们青睐,但铜的性质活泼,极易被氧化.为解决铜电子浆料在高温烧结时铜粉易被氧化的问题,以无水乙醇、正硅酸乙酯、硼酸三丁酯为原料制作SiO_2-B_2O_3溶胶,用SiO_2-B_2O_3溶胶对经过盐酸酸洗过的铜粉进行包覆,将包覆后的铜粉制成浆料并印刷到陶瓷模板上,600℃烧结制备得到铜导电膜层.通过四探针测试仪测试铜导电膜层的电导率,利用扫描电子显微镜(SEM)观察不同量溶胶包覆的铜粉的表面形貌,采用X射线衍射仪(XRD)及热重分析仪(TGA)考察溶胶包覆铜粉700℃烧结后的氧化情况.结果表明,在m(SiO_2-B_2O_3)∶m(Cu)=10%时,硼硅酸溶胶恰好均匀包覆铜粉而无多余溶胶堆积铜粉之间,此时铜导电膜层导电性能最好,其相对电导率为57%;铜粉700℃高温烧结后几乎没有被氧化,铜粉表面仅有极少量的氧化亚铜生成.实验结果证明,在合适的硼硅酸溶胶包覆率下,铜粉在700℃以下具有良好的抗氧化性,铜导电膜层也具有良好的导电性能.

Effects of boron-silicate gel coating on the anti-oxidation and electrical conductivity of copper powders

To prevent the oxidation of copper powder during sintering, SiO2-B2O3 sol was prepared by anhydrous ethanol, tetraethyl orthosilicate and tributyl borate. SiO2-B2O3 sol was used to coat the copper powder which was pretreated by diluted hydrochloric acid. The coated copper powder was used to prepare the paste, then the paste was printed on ceramic substrate and sintered at 600℃.The conductivity of the film was tested by four?probe tester. Scanning electron microscopy ( SEM) was used to observe the surface topograph of copper powder which was coated by SiO2-B2O3 sol, X?ray diffraction(XRD) and thermogravimetric analysis ( TGA) were exploited to characterize the oxidation condition of sintered copper podwers .The results show that when m(SiO2-B2O3):m(Cu)=,copper powders are homogeneously coated with SiO2-B2O3 sol .,the copper film has the highest electrical conductivity, the relative electrical conductivity is 57%;the surface of copper powder has been scarcely oxidized below 700 ℃. Experimental results show that under the suitable coating rate, copper powder has good oxidation resistance and the copper conductive film has good electrical conductivity.