主盐浓度和工艺条件对Sn-Ag-Cu合金镀层组成和形貌的影响

在弱酸性镀液中电沉积得到无铅Sn-Ag-Cu可焊性合金镀层。采用X射线荧光光谱仪(XRF)和扫描电子显微镜(SEM)研究了镀液中主盐浓度和电镀工艺条件对镀层的组成和形貌的影响。研究表明，Sn-Ag-Cu合金的电沉积是正则共沉积。镀液中Sn²⁺和Ag⁺浓度改变对镀层晶粒大小影响较大，Cu²⁺浓度的改变对镀层的平整度影响较大。电流密度增加、pH值下降、温度降低，都能使镀层结晶细致。

Effect of Concentrations of Main Salts and Process Conditions on Compositions and Morphologies of Sn-Ag-Cu Alloy Electrodeposits

Lead-free Sn-Ag-Cu solder alloy electrodeposits were electrodeposited in weakly acidic baths. The effect of the concentrations of main salts and the process conditions on the compositions, and the morphologies of Sn-Ag-Cu alloy electrodeposits were investigated by X-ray fluorescence (XRF) and scanning electron microscopy (SEM). The results indicate that, the electrodeposition of Sn-Ag-Cu alloy is canonical co-electrodeposition. The concentrations of Sn²⁺ and Ag⁺ have influence mainly on the grain size, while the concentration of Cu²⁺ has influence mainly on the planeness of the deposits. The increase of the current density, or the decrease of the pH value or the descent of the bath temperature can accelerate the growth of fine grains in the deposits.