Raman spectroscopy assisted residual stress measurement of plasma sprayed and laser remelted zirconia splats and coatings

This investigation deals with Raman and X-ray assisted stress measurement of plasma sprayed and laser remelted zirconia splats and coating. A Raman peak of tetragonal zirconia phase at 635.38 cm(-1) was used as a reference peak. The tensile residual stress in the as-sprayed and laser remelted single splat lied in the range of 1-2 GPa and 0.2-0.9 GPa, respectively. Surface residual stress of the as-sprayed coating is tensile and its magnitude increases upon laser remelting. Raman spectroscopy results are in agreement with those obtained using X-ray diffraction. It appears that Raman spectroscopy is suitable for quick and accurate measurement of residual stress for small sized Raman active objects and stress depth profiling of the bulk coating. Splat morphology was correlated with particle velocity and temperature. Microstructural aspects and mechanical properties of as-sprayed and laser remelted coating were also investigated.