High Temperature Erosion-Oxidation Behavior of Thermally Sprayed NiCr Based Alloy and Cermets Coatings
The erosion-oxidation (E-O) behavior of high velocity oxy fuel (HVOF) sprayed Ni20Cr alloy as well as WC and Cr3C2 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 (~200Am) 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.
Lucio Salgado and Francisco Ambrozio Filho
C. T. Kunioshi et al., "High Temperature Erosion-Oxidation Behavior of Thermally Sprayed NiCr Based Alloy and Cermets Coatings", Materials Science Forum, Vols. 530-531, pp. 117-125, 2006