Oxidation Behavior of Sn-9Zn-3Bi-xCr Solders under High-Temperature Exposure
The oxidation behavior of Sn-9Zn-3Bi-xCr(x=0, 0.1, 0.3, 0.5) solders under 250℃ has been investigated as a function of exposure time. The evolution of surface and cross-sectional microstructure has been examined through back-scattered electron detector (BSE). Energy-dispersive x-ray spectroscopy (EDX) and x-ray diffractometer analysis (XRD) were also carried out to check the overall composition of the different samples. An oxidation model for Sn-9Zn-3Bi-xCr solders was proposed. The poor oxidation resistance of the solders is attributed to the oxidation of Zn-rich phase and other Zn atoms which diffused to the β-Sn matrix grain boundaries, forming ZnO. Two kinds of Sn-Zn-Cr phases, along the grain boundaries of β-Sn matrix and across the Zn-rich phase, were detected in Cr-bearing solder alloys, which kept the oxygen from diffusing into the bulk of the solder. Adding a small amount of Cr can improve the oxidation resistance of the solders, and the Sn-9Zn-3Bi-0.3Cr alloy had the best oxidation resistance. After 25h of aging under 250℃, the both the two kinds of Sn-Zn-Cr phases re-crystallize.
Jing Hu Anmin Hu Ming Li Dali Mao
State Key Lab Met Matrix Composites, School of Materials Science and Engineering,Shanghai Jiao Tong University, No.800, Dongchuan Road, Shanghai, 200240, China
国际会议
上海
英文
851-854
2011-08-08（万方平台首次上网日期，不代表论文的发表时间）