In order to measure residual stresses in plasma sprayed coatings (Ni-Cr alloy, ZrO2-20%Y2O3), the authors measured at first X-ray stress coefficient K and Young's modulus E of the coating material and then investigated the effect of plasma spraying conditions on the residual stresses by X-ray diffraction method.
The stress relaxation method with a strain gauge was used also to measure stress values for comparison with the values measured by X-ray diffraction method.
The results obtained are summarized as follows;
1) X-ray stress coefficient K and Young's modulus E of coatings are very small in comparison with those of bulk materials.
2) The tensile residual stress values on the Ni-Cr coatings measured by the stress relaxation method are about 30% higher than those measured by X-ray diffraction method.
3) The residual stresses on the Ni-Cr coatings are affected neither by coating thickness nor by spraying distance, but are tend to decrease as the temperature of the base metal rises.
4) No residual stresses on the ZrO2-20%Y2O3 coatings are recognized.
