提高硬铬镀层耐蚀性的双层镀铬工艺  

Double-layer chromium plating process to improve corrosion resistance of hard chromium coating

作　　者：巨根利 

机构地区：[1]陕西北方动力有限责任公司,陕西宝鸡721300

出　　处：《电镀与涂饰》2013年第7期5-7,共3页Electroplating & Finishing

摘　　要：以某型发动机的水泵轴为基体，在同一镀液和镀槽中电沉积制备乳白/光亮双层铬镀层。工艺流程为：前处理－装挂－入槽－疲乳白耐蚀格－镀光亮耐磨格-出槽－清洗－除氢－抛光－检验。镀液组成为：CrO3 200 -250 g/L, H2SO4 2.2 -2.6 g/L,Cr^3＋离子2.0-3.5 g/L。先在60-65 ℃、15-25 A/dm^2下施镀30 min得到乳白铬镀层，随后在55-60 ℃、40-50 A/dm^2下施镀90min,即得乳白/光亮双层铬镀层。双层铬镀层的孔隙率比单层光亮铬镀层小，二者显微L硬度相近，耐磨性优越。实际生产应用表明，双层铬镀层的耐蚀性优于单层光亮铬镀层。A double-layer chromium coating was preparedon a water pump shaft of engine by milky white chromiumplating and bright chromium plating successively in thesame bath and tank. The process flow is as follows：pretreatment, hanging, taking into tank, milky whitecorrosion-resistant chromium plating, bright wear-resistantchromium plating, taking out of tank, washing, hydrogenremoval, polishing, and testing. The plating bath iscomposed of CrO3 200-250 g/L, H2SO4 2.2-2.6 g/L, and Cr3＋2.0-3.5 g/L. The milky white chromium coating wasobtained after plating at 60-65 ℃ and 15-25 A/dm2 initiallyfor 30 min, and the milky white-bright double-layerchromium coating was then obtained after continuous platingat 55-60 ℃ and 40-50 A/dm2 for 90 min. The double-layerchromium coating has lower porosity as well as similarmicrohardness and wear resistance as compared with thesingle bright chromium coating. The practical productionindicated that double-layer chromium coating has better corrosion resistance than single bright chromium coating.

关 键 词：镀硬铬 双层镀层 耐蚀性 耐磨性 孔隙率 硬度 

分 类 号：TQ153.11[化学工程—电化学工业]