Influence of heat treatment and spraying angle on cohesion strength of plasma sprayed deposits

Abstract

The influence of heat treatment and spraying angle on the cohesion strength of plasma sprayed deposits has been studied. Three coatings were selected: NiCr+Cr₂O₃, ZrO₂−1;O₃ (8 wt-%), and Mo. The substrate used was aferritic Cr steel. Heat treatments of 4 h were conducted after spraying in the temperature range 600–900° C and the spraying angle varied from 45 to 90° to the surface of the sample. The cohesion strength of the deposit was measured using tensile tests. For the Cr₂O₃ deposit, the cohesion tensile strength was found to increase strongly with the temperature of the heat treatment but was not influenced by spraying angle. For the ZrO₂−8Y₂O₃ coating neither the heat treatment nor the spraying angle affected the cohesion strength, whereas for the Mo coating, the cohesion strength increased with decreasing spraying angle and heat treatment had no effect.

MST/2012