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目的：在锡青铜基体上化学镀Ni-P合金镀层,提高锡青铜的耐磨性和耐腐蚀性。方法以酸性含锌活化液活化锡青铜试样,在相同的条件下实施化学镀,并对镀态试样进行不同温度(250,400,500℃)下的热处理。对比基体、镀态试样和热处理试样的性能,研究热处理温度对锡青铜化学镀Ni-P合金层微观结构、显微硬度、耐磨性和耐腐蚀性的影响。结果锡青铜表面形成了Ni-P合金镀层,并且镀层无孔隙缺陷,与基体结合良好,沉积速率较快,为10.00μm/h。经热处理后,镀层的微观结构由非晶态向晶态转变,在500℃热处理的镀层显微硬度最大,耐磨性最好。镀态镀层和经250℃热处理的镀层在10%HNO3溶液和10%H2 SO4溶液(10%均为体积分数)中的耐腐蚀性明显好于锡青铜基体,镀态镀层在两种介质溶液中的腐蚀速率分别为0.225,0.146 mg/( cm2·d)。结论采用酸性含锌活化液活化锡青铜基体,可以在锡青铜表面制备出化学镀Ni-P合金镀层,且镀覆效果较好。这表明紫铜化学镀Ni-P合金工艺同样适用于锡青铜。

ABSTRACT:Objective To improve the wear resistance and corrosion resistance of the tin bronze by Ni-P alloy coating. Methods The tin bronze samples were activated by the acid activation solution with zinc and the plating was performed under the same condi-tion. The properties of these state plated samples underwent heat treatment in the different temperatures (250, 400, 500 ℃) were compared, including the matrix, the plating coating and the coating after heat treatment. The impact was investigated of the diffe-rent heat treatment temperatures on microstructure, microhardness, wear resistance and corrosion resistance of electroless Ni-P al-loy coating on the tin bronze. Results The Ni-P alloy coating was formed on the surface of the tin bronze surface, the state plating coa-ting has no void defect with the base;instead, a good combination was observed;moreover, the deposition is faster, namely, 10. 00 μm/h. The microstructure of the coating transforms from amorphous to crystalline after heat treatment was studied, and the microhardness and wearability of the coating was best after 500 ℃ heat treatment, the corrosion resistance of the state plating coa-ting and the coating after 250 ℃ heat treatment was obviously better than the tin bronze substrate in 10% HNO3 solution and 10%H2SO4 solution, and the corrosion rate of the state plating coating was respectively 0. 225 mg/(cm2·d) and 0. 146 mg/(cm2·d) in the two kinds of medium solutions. Conclusion By the acid activation solution with zinc, electroless Ni-P alloy coating can be successfully prepared on the tin bronze surface with a nice plating effect. Our results show that the technology of electroless Ni-P al-loy on copper can be also applied to the tin bronze.