A Study on the Composite Electrodeposition

• Main Authors: Hung-Sheng Shu, 許鴻生
• Other Authors: George C. Tu
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/03689162263610210237

碩士 === 國立交通大學 === 材料科學與工程系 === 87 === Lots of researches on composite electrodeposition have been made in recent years. The applications in ceramic piston engine and die packing are well-known ones; these applications aims to promote wear resistance、usage efficiency and hence increase lifetime. Previous works often concentrate in the deposition mechanism and the promotion of property. There are paucity of researches concerning the microstructure and electrochemical property of the deposited layer. This thesis aims to study the two aspects, together with the mechanical properties, of the coating layer formed by composite electroplating of nickel with nano-SiC ceramic powder. The study employed nickel sulfamate bath added with nano-SiC powder. The pH、temperature and stirring condition were fixed and the current density and concentration of powder were varied. Then the mechanical property、morphology、microstructure and electrochemical property of deposited layer were investigated. Results indicated that the hardness and wear resistance were apparently improved. The hardness increased and the weight loss of wear test decreased with the content of powder in the bath. In electrochemical analysis, the corrosion potential、critical potential and passivation current density of variously formed coating performed differently. In the morphology, the irregular prominence on the composite coating surface was observed by roughness measurement and SEM observation. In the microstructure, the distribution of nano-SiC powder in the composite coatings were identified using SEM、TEM and EDX techniques.