无钯镀镍碳纤维增强Sn-3.0Ag-0.5Cu复合钎料的制备

Fabrication of Palladium-Free Nickel-Coated Carbon Fiber Reinforced Sn-3.0Ag-0.5Cu Composite Solder

采用化学镀法在碳纤维表面制备无钯镍镀层,用粉末冶金法制备了以镀镍碳纤维为增强相的Sn-3.0Ag-0.5Cu复合钎料,借助于SEM、EDS、OM等检测手段对其微观组织进行分析,研究镀镍碳纤维含量对复合钎料微观组织和基本性能的影响。结果表明:镀镍碳纤维主要分布在复合钎料的晶界处;随着复合钎料中镀镍碳纤维含量的增加,其弥散度逐渐降低,熔点变化不大;当镀镍碳纤维含量(质量分数)大于1%时,镀镍碳纤维在晶界处的团聚现象严重,复合钎料的电阻率显著升高。添加1%的镀镍碳纤维有助于减小液态复合钎料在助焊剂界面和Cu基板处的表面张力,降低钎料基体的电流密度,使得复合钎料的润湿性提高,电阻率有所降低。

Palladium-free nickel coating was deposited on the surface of carbon fibers by an electroless plating method. Nickel coated carbon fibers reinforced Sn-3.0Ag-0.SCu composite solder was prepared using the powder metallurgy technique. The microstructure of the composite solder was analyzed by SEM, EDS and OM. The effect of nickel coated carbon fiber contents on the microstructure and properties of the composites solder was studied. The results show that the nickel coated carbon fibers are mainly distributed in the grain boundary of the composite solder. The dispersity of the coated carbon fiber decreases with its content increasing, while the melting point of the composite solder changes little. When the coated carbon fiber content is greater than 1% （mass fraction）, obvious agglomeration appears in the reinforced phase, which leads to the higher electrical resistivity. The 1% addition of coated carbon fiber will be helpful to decrease the surface tension of liquid composite solder between the flux and copper substrate, which causes the excellent wetting effect. At the same time, the current density of solder matrix decreases, which results in the lower electrical resistivity of the composite solder.