AN ASSESSMENT OF THE CORROSION BEHAVIOR OF HIGH-GRADE ALLOYS IN SEAWATER AT ELEVATED-TEMPERATURE AND UNDER A HIGH-VELOCITY IMPINGING FLOW

Laboratory experiments were carried out to investigate the effect of e levated temperature (up to 60 degrees C) and a high velocity impinging flow on the corrosion behaviour of stainless steels and related Ni-ba se and Co-base alloys. DC-electrochemical techniques were employed in conjunction with microscopy to determine the extent and mechanisms of attack under the severe imposed conditions. Experiments demonstrated t he clear effect of increased temperature in facilitating premature bre akdown of passivity on all materials and the effect of the high veloci ty impinging flow was to further shift the passivity breakdown potenti al to more active values but not necessarily to result in greater dept h of attack. Ln addition, the study has indicated that the relative re sistances of the different materials to attack under static, ambient t emperature conditions is altered significantly when they are subjected to elevated temperatures and/or high velocity seawater impingement. C opyright (C) 1996 Elsevier Science Ltd.