Temperature dependence of adhesion strength and elasticity of some heat-resistant coatings

Translated from Probl. Prochnosti; 5: No. 1, l15-118(Jan 1973). The dynamic resonance method was used to determine the temperature dependence of the modulus of elasticity of W, Mo, NiCr, and ZrO₂ coatings applied by the plasma spraying method. An increase in test temperature was found to cause a monotonic decrease in the modulus of elasticity. The absolute value of the modulus of elasticity for plasma-sprayed materials is lower than the corresponding value for the same materials applied by other methods (electron- beam melting, arc melting, and powder metallurgy methods). For W and Mo this difference, for example, was 15 to 20% which may be attributed to a difference in porosity, which also depends on coatmg thickness for plasma-sprayed material. It has been noted that the temperature dependence of the modulus of elasticity has two sections with different temperature coefficients. Thus, investigation results showed that the static adhesion strength of the combination base metal-- coating obtained by the method of continuous plasma spraying, depends on the test temperature and coating thickness. It was shown that the modulus of elasticity of coating materials decreases during the temperature rise to 1200 deg C by 25 to 60% thereby affecting the cohesion strength ofmore » the combination. (auth)« less