Study On Performance And Technique Of Thermal Spraying Coatings Resistant To Wet H₂S Stress Corrosion

Considering the urgent need for methods of resistance to wet H2S stress corrosion cracking (SSCC) during petrochemical production, this thesis, with a view to isolate substrate from the corrosives, introduced arc spraying metallic coatings as a method resistant to SSCC.This thesis put forward a set of laboratory programs in order to check the performance of thermal spraying coatings resistant to SSCC. With these laboratory methods, we checked resistances to SSCC of several kinds of coatings including Zn-Al two-layer coating, Al coating, coatings of Al series and coatings of Fe-Cr series, of which the latter two kinds are made from self-developed cored wires. After the test results of all kinds of coatings were compared with each other, a kind of most protective coating was obtained. In addition, based on detailed analyses of test results and careful observation of corrosion tests, this thesis discussed the protective mechanism of coatings resistant to SSCC and the failure mechanism of some kinds of coatings in wet H2S environment.