铝合金表面涂层失效原因分析及处理建议

Failure Analysis and Suggestions of Aluminum Alloy Coating

通过涂层盐分测试、附着力测试以及腐蚀产物成分分析,研究了铝合金气动头表面涂层在严苛海洋大气环境中的失效原因。结果表明:在冷凝水与高氯化物浓度的共同作用下Cl-透过涂层与铝合金发生电化学反应和水解反应,生成白色的AlO(OH)和Al2O3,说明常规海洋大气环境下使用的环氧底漆加聚氨酯面漆的配套体系不能满足严苛海洋大气下使用要求,建议选用耐盐雾环境类油漆进行重防腐蚀涂装。

The failure reason of cylinder head coating in inclement sea shore atmosphere was investigated by soluble contamination,pull-off test for adhesion and XRD(X-ray Diffraction).Results showed that under the action of condensed water and high chloride concentration,the AlO(OH)and Al2 O3 were formed by electrochemical and hydrolysis reactions between Cl-and aluminum alloy.It meant that the coating system of epoxy primer and polyurethane top finish did not meet the requirement in inclement sea shore atmosphere,and the heavy-duty coatings with high performance of anti-salt-spray were recommended.