電鍍鎳鎢合金之腐蝕與磨耗行為研究

A Study on the Corrosion and Wear Behavior of Electrodeposited Ni-W Coatings

本研究利用梢與環（block-on-ring）腐蝕磨耗系統研究電鍍鎳鎢合金之腐蝕與磨耗行為。研究結果顯示電鍍鎳鎢合金在5 wt%鹽水溶液中利用動態電位極化曲線量測有鈍化行為，隨極化電位提高，無論磨耗速率及表面鎢含量兩者都增加；相反地，摩擦係數隨極化電位增高而下降。經FESEM觀察鍍層表面出現細小蝕孔與龜裂，由XPS分析鍍層表面形成鈍化膜，透過TEM觀察鎳鎢合金腐蝕區出現微裂紋結構。

In this study, a block-on-ring wear tester was employed to investigate the tribocorrosion behavior of electrodeposited Ni-W coatings. Passivation of the Ni-W alloy was observed according to the potentiodynamic polarization curve obtained in a 5 wt% NaCl solution. The result showed that with an increase in the applied overpotential, both the wear rate and the surface W-content of the coating increased. On the other hand, the accompanying coefficient of friction decreased with the increasing overpotential. The FESEM micrograph showed that small pits and cracks appeared on the tested specimen. This micro-cracking phenomenon was also observed in the corroded zone of the Ni-W coating by using TEM microscopy. The XPS analysis confirmed the formation of a passivated film on the corroded surface.