電沉積Co-Mo-Cr合金鍍層微觀結構及耐蝕性研究

Microstructure and Corrosion Resistance of Co-Mo-Cr Coatings Prepared by an Electroplating Process

本研究採用三價鉻鍍浴，於Fe基材上電沉積製備Co-Mo-Cr鍍層，電鍍參數包含Co濃度、Mo濃度、電流密度及溫度等，探討Co-Mo-Cr鍍層的化學組成、表面形貌、微結構、硬度和耐蝕性，並與Cr-C鍍層及Fe基材進行比較。實驗結果顯示，Cr-C鍍層與Co-Mo-Cr鍍層皆屬類非晶相結構，Cr-C鍍層及Co-Mo-Cr鍍層相較於Fe基材具有較高的硬度值。XPS量測Co-Mo-Cr鍍層表面組成，發現有CoO、MoO3和Cr2O3氧化物，有助於提升鍍層之抗蝕能力。在3.5% NaCl水溶液之腐蝕電流密度為1.97×10-6 A/cm2，顯示此鍍層對基材有一定的保護能力。

In this work, Co-Mo-Cr coatings are electrodeposited from Cr (III) based electrolytes onto Fe substrates. The influences of plating parameters including Co concentration, Mo concentration, current density and temperature. The chemical composition, surface morphology, microstructure, micro-hardness and corrosion resistance of the Co-Mo-Cr coatings were studied, and the results were compared to the Cr-C coating and Fe substrate. This study revealed that Cr-C and Co-Mo-Cr coatings were nearly amorphous structure. The hardness of the Cr-C and Co-Mo-Cr coatings were better than the Fe substrate. The surface oxide films, including CoO, MoO3 and Cr2O3 were confirmed by XPS analysis and could provide an excellent corrosion resistance of the coatings. The corrosion resistance of Co-Mo-Cr coatings was measured by using a 3.5% NaCl solution, the result revealed that the corrosion current density of Co-Mo-Cr coatings achieved about 1.97×10-6 A/dm2, this demonstrated that the Co-Mo-Cr coatings had the good protection to the parent metal.