腐蚀对复合银钎料的影响

采用恒温浸泡腐蚀、电化学腐蚀、润湿铺展测试和扫描电子显微镜(SEM)、万能力学试验机等手段研究了复合银钎料中钎剂与钎料合金的腐蚀及钎料腐蚀对钎焊性能的影响。结果表明,银钎料处于含水钎剂环境中,会被钎剂腐蚀。在钎料中加入1.5%~2.5%的Sn,缩小了Ag-Cu-Zn合金中Ag-Zn相与Cu-Zn相之间的电位差,降低了两相之间的微电池效应,Sn细化Ag-Cu-Zn钎料中的共晶相,降低银钎料发生腐蚀的敏感性;用被腐蚀的银钎料钎焊钢,钎焊接头抗拉强度损失,在钎料中添加Sn可抑制损失程度。

Effect of Corrosion on Composite Silver Brazing Filler Metals

The flux corrosion of composite silver brazing filler metals and brazing performance were investigated with SEM, mechanical testing machine, constant temperature immersion corrosion, electrochemical corrosion and wettability test. The results indicate that silver braze could be corroded by the flux in a water-cutting environment. Adding 1.5%~2.5% Sn, the potential difference between the Ag-Zn phase and Cu-Zn phase of the Ag-Cu-Zn alloy was reduced. The microcell effect between the two phases was reduced. The eutectic phase of the Ag-Cu-Zn brazing filler metals was refinement. Therefore, the corrosion sensitivity of silver brazing filler metals was reduced. The tensile strength of brazing steel was damaged by the corroded brazing alloy. Adding Sn to the filler could restrain the loss of strength.