The detection of pitting corrosion in stainless steel using double layer activation

A double layer activation technique has been used to monitor the progress of corrosion of a Type 347 stainless steel in aqueous solution. In nitric acid solution, uniform corrosion and pitting have been separately identified on the 'top-grain' and 'end-grain' surfaces respectively of specimens prepared from rolled plate. 'Bottle-shaped' pitting has also been detected in chloride solution. A second stage of the work demonstrated that pitting could be detected with thick metal between the active surface and the detector using high energy γ-ray-emitting isotopes. (author)