Pulsed laser modification of plasma-sprayed coatings: Experimental processing of hydroxyapatite and numerical simulation

A pulsed C/O-2 laser was used to treat plasma-sprayed hydroxyapatite coatings. Pulses of 0.74 ms duration and powers equal to 41.6 and 45.3 W were focused onto a 300 mu m spot of the coatings surface. The laser beam was scanned with speeds of 6.4 and 9.6 mm/s. The morphology of laser-treated deposits was observed by scanning electron microscopy (SEM) and the crystal phases identified using X-ray diffraction (XRD). This technique enabled also the determination of quantitative phase composition. The laser treatment process was modeled using the Fusion-2D, software and the temperature fields and depth of molten material were predicted. The latter were compared with the experimental ones found in metallographically prepared cross-sections. A reasonable convergence between the model and experiment was achieved after careful optimisation of initial material parameters as such coefficient of optical absorption and emissivity. (c) 2006 Elsevier B.V. All rights reserved.