热喷涂锌铝复合涂层的耐硫化物的应力腐蚀行为

Performance of Sulfide Stress Corrosion Resistance of Zn-Al Two-Layer Coating and Al Coating

对热喷涂底锌面铝复合涂层与铝涂层做了耐硫化物应力腐蚀的对比试验．试验结果表明：锌铝复合涂层并没有保持锌、铝的各自优点，改善原来的不足；相反，在底锌面铝复合涂层中，由于腐蚀介质渗透到底锌层，使锌层优先溶解，导致面铝层开裂脱落，进而使整个涂层失效．同时，探讨了锌铝复合涂层在ＮＡＣＥ的标准饱和Ｈ２Ｓ水溶液的应力腐蚀失效过程，指出了热喷涂锌铝复合层设计的不合理性．

Stress corrosion tests were made to compare the performance of Zn-Al two-layer costing with that of Al coating in H2S-containing NACE solution. The results of tests show that Zn-Al two-layer coating(not as we expected) neither remains the advantages of Zn and Al coatings nor offsets the disadvantages of them. In fact when corrosive permeates the Zn layer of Zn-Al tWo-layer coating, preferential solution of Zn layer will take place, which results in the crevice of Al layer, further, the failure of the whole coating. This paper discussed the stress corrosion failure of Zn-Al two-layer coating in H2S-Saturated aqueous solution, and pointed out the irrationality of the design of Zn-Al two-layer coating..