Microstructural and topographic chanages in zirconia ceramic materials by Nd:YLF laser irradiation
Tutor / director / avaluadorJiménez Piqué, Emilio
Tipus de documentProjecte Final de Màster Oficial
Condicions d'accésAccés restringit per decisió de l'autor
The main focus of this project was to investigate the role of different laser parameters, such as laser current intensity and pulse repetition frequency, on ablation characteristics and damage of induced surface patterns on different formulations of zirconia ceramic materials. The testing samples were 3Y-TZP, 10Ce,3Ca-TZP, and two commercially available alumina-zirconia composites. A Nd:YLF UV pulsed laser emission system with a nanosecond pulse width is employed to create laser patterns. The resulting topography and microstructure was characterized using an interferometer, SEM/FIB and Raman Spectroscopy. The results include an ablation threshold energy of 12.92 μJ per pulse on all material tested. The craters generated depend on the laser processing conditions, resulting in deeper and wider craters with increasing pulse number and fluency. Surface cracking, intergranular cracking, and columnar-like grain growth were observed with SEM on 3Y-TZP and 10Ce,3Ca-TZP sample materials’ heat affected zone. No phase transformation on the surface of 3Y-TZP material was detected by Raman spectroscopy as a result of laser irradiation. However, this does not mean that a small amount of monoclinic phase could not be present in the heat affected zone of the crater. Inhomogeneous texture on grains surrounding produced cracks are attributed to twinning and martensitic transformation from tetragonal to monoclinic phase. Alumina-zirconia composited present higher resistance to material removal by laser irradiation.