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论文类型： 会议论文

发表时间： 2009-12-26

收录刊物： EI、CPCI-S、Scopus

卷号： 97-101

页面范围： 679-+

关键字： The liquid structure; viscosity; Sn-Cu solder

摘要： The liquid structure of two lead-free solder Molten alloys, Sn-0.5Cu and Sn-1.8Cu (wt.%), has been examined using X-ray diffraction method. The main peak for liquid structure of Sn-0.5Cu is similar to that of pure Sn. A pre-peak has been found in the low Q part on the structure factor S(Q) of Sn-1.8Cu tested under 320 degrees C, but it disappeared finally when the testing temperature reached 350 degrees C. The both viscosity was measured using a torsional oscillation viscometer. It was found that the anomalous variations of viscosity had a direct relation with the transition of the liquid structure, which is consonant with the results of high temperature X-ray diffraction. The microstructure of the solder matrixes as well as interfacial reaction between liquid solders and Cu substrates was also studied. The results show that particle-like Cu6Sn5 intermetallic compounds (IMCs) emerge in Sn-1.8Cu solder matrix. The IMC layer at Sn-1.8Cu/Cu joint is thicker than that at Sn-0.5Cu/Cti interface. The correlative effect of liquid structure on phase evolution in the solder joints is analyzed.