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论文类型：期刊论文

发表时间：2009-06-01

发表刊物：50th Electronic Materials Conference

收录刊物：SCIE、EI、CPCI-S

卷号：38

期号：6

页面范围：828-833

ISSN号：0361-5235

关键字：Lead-free solder; Sn-Cu alloy; viscosity; surface tension; wetting property

摘要：The viscosity of Sn-0.7wt.%Cu and Sn-2wt.%Cu lead-free solders was measured using a torsional oscillation viscometer from 503 K to 773 K. For both melts the viscosity decreased with increasing temperature, and the values dropped abruptly at certain temperature ranges, i.e., 553 K to 573 K for Sn-0.7Cu and 573 K to 603 K for Sn-2Cu. Correspondingly, two segments, a low-temperature zone and a high-temperature zone, were found on both eta-T and ln eta-1/T plots, where eta is the viscosity and T is the absolute temperature. The activation energy epsilon and the unit volume of flow nu (m) were obtained by applying the parameters of linear fitting for each temperature zone. The surface tension of the solders was calculated using the measured viscosity values, and the results were checked by measuring the wetting angles of metallurgical reactions between the solders and the Cu substrates. Both viscosity and surface tension are closely related to the liquid structure of the solder alloy.