Diffusional Coating Of A-625 Alloy By Reactive Plasma Surfacing For Arresting Crevice Corrosion

This investigation addresses an exploratory development effort whioh applies an innovative adaptation of plasma arc surfacing technology to facilitate the convenient introduotion of a diffusional coating layer out of the surface of A-625 alloy flanged pipe conneCtions such a strategy will be expected to arrest crevice corrosion and related phenomenon The approach will be to modify plasma arc surfacing teohnology so that selected volatile reactants oan be simultaneously introduoed into the plasma arc region where as a consequence of the highly energetic conditions present, in situ formation of diffusional coatings will proceed The proposed surfacing technology is expeCted to be particularly compatible for the simultaneous treatment of raised flat and reoessed alloy surface topologies Tbe wide treatment swath the convenient modification of existing plasma arc welding teohnology the resistanCe to mechanical damage the low app1ication temperatures the ability to visually determine the presence of the converted surface layer and most signifioantly the ability to apply the treatment in situ as or just prior to the final step in assembly of a shipboard piping system makes this corrosion prevention surfacing treatment more economic and effective than other strategies currently available