微量稀土La对Sn-Zn-Al无铅焊料性能的影响

采用真空熔炼技术成功制备Sn-(8.98-x)Zn-0.02Al-xLa(x=0.02～0.12)焊料。采用XRD衍射、DTA、SEM等手段分析了焊料的熔点、显微结构及焊料对Cu基板的润湿性等性能。结果表明,添加适量的稀土元素La能较好地提高Sn-Zn-Al基焊料熔点,改善焊料的铺展能力和组织均匀性。在Sn-(8.98-x)Zn-0.02Al-xLa焊料中,稀土La的最佳添加量为0.04%。     

Experimental investigation on phase equilibria of Ce-Sn-Zn system at 400℃

The Ce-Sn-Zn alloys were prepared by furnace melting. The isothermal section of the Ce-Sn-Zn system at 400 oC over the whole composition range was established by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). A new ternary compound, CeSn 2 Zn 2 , was discovered in the present work. This compound adopted CaBe 2 Ge 2 structure type (space group P4/nmm) with the lattice parameters of a=0.4455 (9) nm and c=1.0348 (1) nm. The existence of previously known ternary compounds, CeSnZn and Ce 2 SnZn 3 , were confirmed, too. The maximum solubility of Zn in CeSn 3 was determined to be 12.7 at.%.