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腐蚀科学与防护技术 1993
STUDY ON PREFERENTIAL DISSOLUTION OF DUPLEX WELDMENTS OF STAINLESS STEELS
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Abstract:
The preferential dissolution mechanisms of duplex weldments of stainless steels have been investigated by means of potentiodynamic scanning and potentiostatic etching in acid solutions containing chloride. It was observed that the preferential dissolution of duplex weldments depended on the electrochemical potential. Both in the transpassive region and the lower part of the active range existed the preferential dissolution of ferritic phase. The preferential dissolution of austenitic phase took place in the higher potential part of the active range. There was a duplex phase corrosion range between the lower and higher potentiol of active range. In the transpassive and near transpassive regions dissolution took place in ferritic phase preferentially, then expanded to austenitic phase. The influence of chloride concentration and temperature on preferential dissolution of duplex weldments is also discussed.