Nano-crystalline Sn-Co-X Alloy Alternative to Decorative Chromium Plating

Decorative chromium demand in the worldwide market is more than three times that of hard chromium. However, chromium plating processes have long been known to be hazardous. The corrosion resistance of a nano-crystalline Sn-Co-X alloy as an alternative for decorative chromium has been studied. The corrosion resistance of Sn-Co-X is better than trivalent chromium, hexavalent chromium, and it is much better than coarser- grained Sn-Co alloy, our research shows. The microstructures of Sn-Co-X alloy were analyzed by SEM, TEM, XPS and AES. The mechanism of its excellent corrosion resistance is described herein.