THERMAL SPRAY COATINGS ON YANKEE DRYERS

Several failure investigations and recent research on thermal spray co atings on Yankee dryer surfaces show at least three modes of environme ntally induced degradation. Corrosion may occur with the ingress of ce rtain chemicals into coating pores. Erosion or corrosion is manifested by streaks at local sites of high doctor blade loading. Erosion and c racking occur due to coating parameters, thermal stress, and different ial expansion. While most of the results described in this paper are f rom investigations of molybdenum, stainless steel coatings also are di scussed.