CO2 laser induced microstructure features in magnesia partially stablised zirconia bioceramic and effects thereof on the wettability characteristics

For the purpose of improving the wettability characteristics of a magnesia partially stabilised zirconia (MgO-PSZ) bioceramic and thereby enhancing its adhesion with biological tissue, CO2 laser treatment was used to modify the surface properties of the MgO-PSZ. The microstructures changes and crystal sizes obtained at varied power densities were investigated. Contact angle measurements of a set of test liquids were a clear indication that CO2 laser surface treatment of the MgO-PSZ augmented the wettability characteristics of the MgO-PSZ. It was found that the increase in surface roughness, surface O2 content, and surface energy following CO2 laser treatment brought about the improvement in the wettability characteristics of the MgO-PSZ. Moreover, surface energy was found to be the primary factor governing the change of wettability characteristics. Further analysis revealed that the change in surface energy was related to the nature of the microstructure and crystal size. The highest surface energy is corresponding to the modified MgO-PSZ with the largest crystal size. It is believed that change in microstructure, particularly the increase in crystal size, generates the higher surface energy of the MgO-PSZ after CO2 laser treatment.