Investigation of residual stresses in flame sprayed Ni-based wear resistant coatings by the hole-drilling and X-ray methods

摘要

The present investigationwas carried out in order to determine residual stresses in Ni-basedself-fluxing alloy based high velocity oxy-fuel (HVOF) coatings with different wear resistant additives. The main components of the alloy were Ni, Cr, Si and B. To increase the wear resistance of self-fluxing NiCrSiB alloy based coatings, different ceramics and hardmetals (WC-Co, TiC-NiMo and Cr_2C_3-Ni) wereadded. Residual stresses were measured bythe hole-drilling method and the X-ray method. The incremental hole-drilling technique combined with the integral method was applied. This combinedmethod allows to analyse non-uniform through-thickness residual stresses. The results obtained with the incremental hole-drilling method indicate that through-thickness residual stress distribution is non-uniform. The determined residual stresses were tensile on the surface of the coating and becamecompressive toward the interface. The values of the modulus of elasticity and microhardness of the coatings were obtained by instrumented indentation. The microstructures of the studied coatings were investigated with the SEM technique.