Residual Stress Evolution during Deposition of Thermal Sprayed Coatings

First-principle-based modeling of residual stresses during deposition of thermal spray coatings has always been limited by the stochastic occurrence of stress relief mechanisms. Moreover, deposition conditions such as particle melting state and kinetic energy, deposition temperature, and others, can affect the stress developed during coating formation. In this regard, in the present study, the residual stress evolution of several sprayed materials (Ni, NiCr, NiCrAlY, WC-Co, CrC-NiCr, Mo, T-800, YSZ, etc) and torches (various APS and HVOF) is discussed considering process parameters and material specific properties. The main experimental tool used in this study for in situ monitoring of stress buildup was the ICP-In situ Coating Property- sensor, which monitors the curvature of a thin plate during the spray run. The residual stress measurements layer by layer via the curvature method are analyzed with reference to Tsui & Clyne analytical model. Results are compared to neutron and X-ray diffraction measurements.