EFFECTOF SOLDERING CONDITION ON THE TENSILE STRENGTH TITANIUM SOLDER JOINT WITH 14K GOLD SOLDER

Choi, Jeoung Ho; Kim, Tae Jo; Song, Kwang Yeob; Park, Charn Woon

Abstract

This study was performed to evaluate the tensile strength of solder joint in titanium and the wettability of 14K gold solder on titanium. Two pieces of titanium rod 30 mm in length and 3mm in diameter were butt-soldered with a 14K gold solder using the electric resistance heating under flux-argon atmosphere, the infrared heating under argon atmosphere, and the infrared heating under vacuum-argon atmosphere. A tensile test was performed at a crosshead speed of 0.5mm/min, and fractere surfaces were examined by SEM. To evaluate the wettability of 14K gold solder on titanium, titanium plates of a 17x17x1mm were polished with #80-#2000 emery papers, and the spreading areas of solder 10mg were measures by heating at 840 * for 60 seconds. The solder-matrix interface regions were etched by the solution of 10% KCN-10%(NH4)2S2O8, and analyzed by EPMA. The results obtained were summarized as follows: 1. The maximun tensile strength was obtained when the titanium surface was polished with #2000 emery paper and soldered using the electric resistance heating under fluxargon atmosphere. Soldering strengths showed the significant difference between the electric resistance heating and the infrared heating(p<0.05). 2. The fracture surfaces showed the aspect of brittle fracture, and the failure developed along the interfaces of solder-matrix reaction zone. 3. The EPMA data for the solder-matrix interface region revealed that the diffusion of Au and Cu occurred to the titanium matrix, and the reaction zone showed the higher contents of Au, Cu and Ti than others.