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汽车散热器新型铝合金钎焊接头腐蚀行为的分析

Research on corrosion of automobile condenser brazed with novel aluminium alloys

  • 摘要: 采用微区电化学测试和浸泡试验法研究了采用自行新研制的汽车散热器用新型铝合金管(Minicore)钎焊接头分别在0.1 mol/L(pH=6)和0.6 mol/L NaCl(pH=3)溶液中的腐蚀行为.文中采用微区电化学测试和浸泡试验法对母材、钎焊缝及腐蚀形貌的显微组织进行了分析,焊接使用在保护气氛下钎焊,钎料为Al-Si合金(AA4343).结果表明,新型Minicore铝合金管比钎缝区域的点蚀电位高.扫描电镜(SEM)结果表明,临近钎缝的铝合金管未发生晶间腐蚀,而钎缝区域(20~30μm)呈现晶间腐蚀,晶间腐蚀由钎缝Al-Si共晶组织中的铝基体发生了优先溶解,留下了富硅的合金相.

     

    Abstract: The corrosion behaviour of automobile condenser brazed with novel aluminium alloys have been studied in 0.1 mol/l NaCl(pH=6) and 0.6 mol/l NaCl(pH=3) solutions by microelectrochemical measurements and immersion test.The microstructure of the fin materials,tube alloys and brazing region and corrosion morphology have been investigated by SEM.The controlled atmosphere brazing(CAB) was used and Al-Si alloys was used for clad alloys for aluminium brazing sheet.The results indicate tube region shows less susceptibility to corrosion attack than the brazed region.The SEM results show that the tube region has no intergranular corrosion and the thickness of the brazed region is about 20-30 μm.The brazed region shows intergranular corrosion,but it is corrosion of the eutectic of Al-Si with α-aluminium is preferential dissolution and Si-rich intermetallic particles remains.

     

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