In对Sn-8Zn-3Bi无铅钎料润湿性的影响

首先采用铺展法测试了Sn-8Zn-3Bi-(0～5)In钎料合金的铺展性.结果表明,少量In的加入提高了钎料的润湿性.当In含量达到0.5%时(质量分数,下同),钎料在铜基底上的铺展面积最大.采用气泡最大压力法对Sn-8Zn-3Bi-(0～1.5)In钎料熔体进行了表面张力测试.加入0.5%的In大大降低了Sn-8Zn-3Bi钎料熔体的表面张力,但进一步增加In的含量导致熔体表面张力增大.最后采用润湿平衡法对上述钎料进行了润湿力测试.结果表明0.5%In的加入使合金的润湿力达到最大,其原因是钎料/铜界面的界面张力减小.

Influence of Indium on Wetting Behaviors of Sn-8Zn-3Bi Lead-Free Solders

The wetting behaviors of the Sn-8Zn-3Bi-(0~5)In alloys on Cu substrate were tested by an area-of-spread method. The spreading areas of these alloys increase with the addition of In before In content reaches 0.5wt%, which indicates small addition of In can improve the wettability of Sn-8Zn-3Bi based alloys. Bubble's largest pressure method was applied to measure the surface tensions of the Sn-8Zn-3Bi-(0~1.5)In melts. Adding 0.5wt% In into the foundry alloy, the surface tension of the alloy is lower than that of the other alloys. But more addition of In causes degradation of the surface tension. Wetting balance method was used to evaluate the wetting forces of these solders on Cu substrates. With addition of 0.5wt% In, wetting force reaches the maximum, which results from decrease of the solder/Cu interfacial tension.