High Temperature Erosion-Oxidation Behavior of Thermally Sprayed NiCr Based Alloy and Cermets Coatings C. T. Kunioshi, O. V. Correa, L. V. Ramanathan Corrosion Laboratory – Instituto de Pesquisas Energéticas e Nucleares, IPEN/SP P. O. Box 11049, Pinheiros, CEP 05422-970, São Paulo, Brazil Email: kunioshi@ipen.br , lalgudi@ipen.br Abstract The erosion-oxidation (E-O) behavior of high velocity oxy fuel (HVOF) sprayed Ni20Cr alloy as well as WC and Cr 3 C 2 cermet coatings on a steel substrate were studied. The E-O tests were carried out in a rig with specimen assemblies that were rotated through a fluidized bed of erodent particles in the temperature range 500-850°C and with erodent impact velocities of 2.5-19.5 ms -1 . Alumina powder (~200µm) was used as the erodent. The E-O resistance of the coatings was determined as wastage, as a function of temperature. The three coatings did not exhibit any significant change in E-O at temperatures up to 500-600°C. At higher temperatures, wastage increased with temperature, reached a maximum at 700°C and then decreased with further increase in temperature. Different E-O regimes were identified. The specimen surfaces were examined in a scanning electron microscope and their roughness determined. E-O maps have been drawn that define conditions under which the coatings undergo low, moderate and severe wastage. Keywords: Erosion, erosion-oxidation, erosion-oxidation maps, cermet coatings, composites, HVOF, surface roughness.