Directional Solidification and Liquidus Projection of the Sn-Co-Cu System

作者：Chen Sinn Wen^*; Chang Jui Shen; Pan Kevin; Hsu Chia Ming; Hsu Che Wei

来源：Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science, 2013, 44A(4): 1656-1664.

DOI：10.1007/s11661-012-1545-2

This study investigates the Sn-Co-Cu ternary system, which is of interest to the electronics industry. Ternary Sn-Co-Cu alloys were prepared, their as-solidified microstructures were examined, and their primary solidification phases were determined. The primary solidification phases observed were Cu, Co, Co3Sn2, CoSn, CoSn2, Cu6Sn5, Co3Sn2, gamma, and beta phases. Although there are ternary compounds reported in this ternary system, no ternary compound was found as the primary solidification phase. The directional solidification technique was applied when difficulties were encountered using the conventional quenching method to distinguish the primary solidification phases, such as Cu6Sn5, Cu3Sn, and gamma phases. Of all the primary solidification phases, the Co3Sn2 and Co phases have the largest compositional regimes in which alloys display them as the primary solidification phases. There are four class II reactions and four class III reactions. The reactions with the highest and lowest reaction temperatures are both class III reactions, and are L + CoSn2 + Cu6Sn5 = CoSn3 at 621.5 K (348.3 A degrees C) and L + Co3Sn2 + CoSn = Cu6Sn5 at 1157.8 K (884.6 A degrees C), respectively.

• 出版日期2013-4
• 单位清华大学