稀土元素Nd对Sn-Zn-Ga无铅钎料组织及性能的影响

研究了添加合金元素Ga及稀土元素Nd对Sn-Zn钎料润湿性能、显微组织和焊点力学性能的影响.结果表明,在钎料中适当添加Nd元素,可以提高钎料的润湿性能,当Nd元素的质量分数为0.1％时,钎料的润湿力最大,润湿时间最短,润湿性能达到最佳.同时适当升高温度时润湿性能得到改善.随着Nd元素的加入,钎料中大块的黑色针状富锌相逐渐变少,钎料基体组织得到细化,在Nd元素的添加量达到0.1％时,钎料的组织最为均匀、细小.同时Nd元素的加入可以改善焊点的力学性能,在Nd元素含量为0.1％时抗剪强度增至最大.因此Nd元素在Sn-9Zn-0.5 Ga钎料中的最佳添加量为0.1％左右.

Effects of Nd on microstructure and properties of Sn-Zn-Ga Lead-free solder

The effects of alloying element Ga and rare earth element Nd on the wettability,microstructure and mechanical properties of the Sn-Zn solder were investigated. The results indicated that the wetting properties of the solder were improved with appropriate addition of Nd. When the Nd content was 0.1wt%,the wetting properties reached the best. It was also found that the wettability was improved when the temperature rose properly. With the Nd content increasing,the amount of black needle-like Zn-rich phases gradually decreased and the matrix microstructure of the solder was refined. When the Nd content reached 0.1wt%,the grains in the solder was the most uniform and smallest. Meanwhile,the mechanical properties of the joints made with solders containing Nd were also improved, and the shear strength of the resultant joints with solder containing 0.1wt% Nd reached the maximum. Therefore,the optimal amount of Nd in the Sn9Zn0.5Ga solder was around 0.1wt%.