Influencia de los esfuerzos residuales en la adherencia de recubrimientos de Al2O3-40% TiO2 depositados mediante proyección térmica por combustión

The effect of preheating temperature of substrates and thickness of coatings on residual stress and the influence of them on the adhesion of Al2O3-40 wt.% TiO2 coatings manufactured by oxy fuel flame spraying process were studied. Previously to spraying process, the substrate were preheating to 150 and 250 °C and then, feedstock powders were sprayed during different times obtaining coatings between 0.05 mm and 0.3 mm in thickness. Residual stresses were measured using the bending method from Modified Stoney and Brenner-Senderoff equations and the adhesion tests were performed by the pull-off test. The results obtained indicate that the residual stress produced in all samples was compressive, and their magnitude increases with the thickness of coating and decreasing the preheating temperature of the substrate, and then, the higher resistance was reached in thin coatings deposited onto substrates preheated at 250 °C.