铝基钎料真空钎焊接头的腐蚀性  

Corrosion of brazed joints with aluminum-based filler metals in vacuum

作　　者：陈学定[1] 宋强 俞伟元[1] 宋翀旸[1] 

机构地区：[1]甘肃工业大学材料科学与工程学院,兰州730050 [2]山东盛大纳米材料有限公司,山东泰安271000

出　　处：《焊接学报》2003年第1期40-43,共4页Transactions of The China Welding Institution

基　　金：甘肃省科技攻关项目 (GS0 0 2 -A5 2 -0 2 6 )

摘　　要：采用NaCl的质量分数为 3.5 %的溶液对四种Al-Si-Cu钎料的真空钎焊接头进行全浸试验 ,对腐蚀后的钎焊接头进行观察 ,分析接头的腐蚀类型 ,研究接头的腐蚀机理 ,对Cu的晶界偏析及扩散进行了讨论。结果表明 ,铝基钎料真空钎焊后的接头仍然存在腐蚀问题 ,腐蚀产物为AlCl3 、Al(OH) 3 、Al(OH) 2 Cl,腐蚀类型有点蚀和晶间腐蚀 ;并且随着Cu含量的增加腐蚀加重 ,Cu的偏析与扩散对接头腐蚀行为产生重要的影响 ,在晶界形成Al2 Cu ,使晶界周围形成贫Cu区 ,与晶粒内部处于钝态的αAl存在较大电位差 ,构成局部腐蚀电池 ,形成晶间腐蚀。Four kinds of brazed joints brazing with Al-Si-Cu filler metals in vacuum were corroded in 3.5 pet NaCl solution. The microstructure, corrosion patterns, as well as the segregation and diffusion of Cu element in the grain boundary of the as-corroded joints were investigated, and a corrosion mechanism was proposed. The results showed that corrosion such as pitting and intergranular corrosion still existed in the brazed joints, and the corrosion contaminants were A1C13, Al (OH)3 and Al(OH)2Cl. As Cu content in the Al-Si-Cu filler metals increased, the corrosion of the joints became more serious. It was found that the segregation and diffusion of Cu element significantly affected the corrosion characteristics. A poor Cu element area was observed nearby grain boundary, and Al2Cu phase was found on the grain boundary. Because of the potential difference between the grain and grain boundary, a local corrosion cell was formed and resulted in the intergranular corrosion of the joint.

关 键 词：铝基钎料 真空钎焊接头 腐蚀性 偏析 扩散 

分 类 号：TG457.14[金属学及工艺—焊接] TG454