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Optics and Lasers in Engineering, Volume 51, Issue 2, February 2013, Pages 159-166.
Mohammed Jasim Kadhim, Sami Ibrahim Al-Rubaiey, Ali Sabea Hammood
Department of Production Engineering and Metallurgy, University of Technology, Baghdad, Iraq
Engineering College, University of Kufa, Al-Najaf, Iraq
Abstract
A 2 kW CO2 laser was used to modify the surface of air plasma sprayed (APS) 7.8 wt% yttria partially stabilized zirconia (YPSZ) coatings; the effects of laser specific energy was investigated. The sealed coatings were characterized by SEM, EDS, WDS, XRD and microhardness. It was possible to control the cell size (or well-sintered ‘domain like’ structure), crack width, depth of sealing and depth of concavity by carefully adjusting the specific energy. The microstructure of the sealed coatings was characterized by a cellular structure at all laser parameters studied. Cracks formed under optimum specific energies (1–2 J/mm²) were seen to be shallow and they do not penetrate through the plasma sprayed coating. The sealed coatings have much lower roughness and higher hardness than non-treated coatings indicating the beneficial effect of plasma treatment.