采用碱性焦磷酸盐体系在45钢基体上电刷镀制备了铜锡合金镀层。考察了刷镀电压、刷镀液中氯化亚锡质量浓度、pH、刷镀时间等工艺参数对镀层的化学成分、物相结构、显微硬度和附着力的影响。结果表明：刷镀液pH为8.0~10.0时，随电压增大，镀层锡含量呈下降趋势。当氯化亚锡为9.0 g/L，pH为8.0~9.5时，刷镀液稳定，镀层主要由Cu20Sn6和Cu6Sn5构成，锡含量处于高锡水平(质量分数44.10%~57.40%)，显微硬度较高。当pH为9.5~10.0时，刷镀液不稳定，镀层主要由Cu20Sn6和α-Cu构成，锡含量处于中锡水平(质量分数35.60%~44.50%)，显微硬度较低。随刷镀时间延长，镀层的孔隙率显著下降，刷镀18 min所得镀层非常致密。刷镀电压为4 V时所得厚度为18.00~21.00μm的镀层的附着力在18~23 N之间。%Copper–tin alloy deposits were prepared using electro-brush plating with alkaline pyrophosphate bath on 45 steel substrate. The effects of process parameters such as plating voltage, mass concentration of stannous chloride in bath, pH, and brush plating time on composition, phase structure, microhardness, and adhesion strength of the deposits were studied. The results showed that the tin content of the deposit decline with the increasing of plating voltage at bath pH 8.0-10.0. The bath containing stannous chloride 9.0 g/L is stable at pH 8.0-9.5 and produces the deposits mainly composed of Cu20Sn6 and Cu6Sn5 with a high tin content (44.10wt% to 57.40wt%) and high microhardness, while is unstable at pH 9.5-10.0 and produces the deposits mainly composed of Cu20Sn6 andα-Cu with a medium tin content (35.60wt% to 44.50wt%) and relatively low microhardness. The porosity of the deposit is decreased significantly with the extending of brush plating time. The deposit obtained by brush plating for 18 min is very compact. The adhesion strength of the deposits having a thickness of 18.00-21.00μm obtained at a brush voltage of 4 V is 18-23 N.
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