High-strength Copper Alloy and Its Composite Electrodeposition

• Main Authors: Chang Ching-fong, 張靜芳
• Other Authors: 李春穎
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/97485154067184548452

碩士 === 大葉大學 === 機械工程研究所碩士班 === 93 === Copper has been widely used in industrial applications due to its excellent conducting properties both in thermal and electrical aspects. However, the inferiority in mechanical strength makes the scope of its application restricted. Therefore, improving the mechanical strength, while retaining the conducting properties, becomes an important research topic. During the last decades, most studies in the composite electroplating concentrated on the enhancement of the codeposition of alumina in copper matrix. The discussion on the relationship between the material property and microstructure of the composite coating is rarely seen in the literature. A closed electroplating system was fabricated in this thesis and an experimental study on the effect of process parameters for this alumina/copper codeposition was conducted. The field-emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) were employed in the examination of the microstructure of the coating. On the other hands, X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and hardness tester were used to study the correlation between the microstructure and mechanical properties. The results showed that the addition of cobalt or thallium ion in the electrolyte can increase the amount of codeposited alumina. Nevertheless, the codeposited alumina was only found near the surface of the coating instead of uniform distribution through the thickness. It is concluded that for the acid electrolyte of copper sulfide, the additive of Tl or Co ion, pH of the solution and process parameters can used to tune the preferred orientation, defect of the microstructure and the hardness of the coating.