电沉积Cu-Sn-Zn-PTFE复合镀层及其性能的研究

Electrodeposition of Cu-Sn-Zn-PTFE Composite Coating and Its Self-lubricating Property

针对Cu-Sn-Zn合金镀层自润滑性能差的缺点,在Cu-Sn-Zn合金镀液中加入聚四氟乙烯(PTFE)乳液,采用电沉积方法在45#钢表面制备了Cu-Sn-Zn-PTFE复合镀层。镀液组成和工艺条件为:焦磷酸铜24g/L,氯化锌12g/L,甲基磺酸锡15g/L,焦磷酸钾20g/L,酒石酸钾钠22g/L,全氟辛基磺酸钾18g/L,PTFE乳液32g/L,温度50~60℃,pH值11.5,电流密度1.2A/dm^2,搅拌转速300~600r/min,时间120min。考察了镀液中PTFE的质量浓度对镀层的耐磨性、显微硬度、结合力、PTFE的质量分数、外观的影响,并表征了Cu-Sn-Zn-PTFE复合镀层的表面形貌、结构和成分。随着镀液中PTFE的质量浓度的增加,镀层的耐磨性改善,显微硬度和结合力下降,PTFE的质量分数先增大然后保持不变。镀液中PTFE的最佳质量浓度为32g/L,在此条件下制得的Cu-Sn-Zn-PTFE复合镀层的综合性能最佳。

In order to solve the problem of the poor self-lubrication of Cu-Sn-Zn alloy, Cu-Sn- Zn-PTFE composite coating was prepared on surface of 45^# stainless steel from Cu-Sn-Zn plating bath containing polytetrafluoroethylene （PTFE, adding in the form of emulsion） by electrodeposition. The bath composition and process conditions are as follows： copper pyrophosphate 24 g/L, zinc chloride 12 g/L, tin methanesulfonate 15 g/L, potassium pyrophosphate 20 g/L,potassium sodium tartrate 22 g/L, potassium perfluorooctane sulfonate 18 g/L, PTFE 32 g/L, temperature 50-60 ℃, pH value 11.5, current density 1.2 A/din2 , stirring rate 300-600 r/rain, time 120 min. The effects of PTFE content in bath on the wear resistance, microghardness, adhesion, PTFE content of coating and appearance of Cu-Sn-Zn-PTFE composite coating were studied. The morphology, structure and composition of Cu-Sn-Zn-PTFE composite coating were also characterized. With the increasing of PTFE content in bath, the wear resistance of coating improves, the microhardness and adhesion of coating decreases, and PTFE content of coating increase firstly and then remain unchanged. The Cu-Sn-Zn-PTFE composite coating obtained at the most suitable dosage of PTFE 32 g/L features the best comprehensive performance.