| Summary: | 碩士 === 國立臺北科技大學 === 材料科學與工程研究所 === 99 === In past years, pure metal and alloy targets were usually made by melting and casting methods. However, the ingredient segregation, non-uniform microstructure and porosity defects of Cr-Cu alloy targets were frequently produced by melting. Even if the subsequent heat treatment and the hot-working process will not be able completely eliminate. Therefore, we produced the Cr-Cu alloy targets via vacuum sintering, hot isostatic pressing (HIP) and hot pressing (HP) of powder metallurgy in this study. Moreover, we carried out a series of experimental tests to explore the characteristics and effects of different powder metallurgy processes on the Cr-Cu alloy targets.
The experimental results show that the relative density of Cr50Cu50 and Cr60Cu40 vacuum sintering targets can reach to 99.42 % and 99.69 %, and apparent porosity decreases to 0.54 % and 0.30 % after 1050°C 175 MPa HIP treatment for 4 h, respectively. It shows that we can obtain the high density and high properties of Cr-Cu alloy targets, and eliminate the closed pores by employing the HIP treatment.
Due to the poor density of Cr70Cu30, vacuum sintering targets that will lead to it can not be efficiently produced by HIP treatment. However, the 1000°C 60 MPa 1 h of hot pressing of Cr70Cu30 target achieves the best density (97.62 %) and lower apparent porosity (0.65 %). This result shows that we can effectively eliminate the closed pores of Cr70Cu30 target by way of hot pressing treatment. In addition, we can also produce and make the Cr70Cu30 target with better performance of microstructure and electrical conductivity.
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