Ceramics-Silikáty 57 (3) 225-231 (2013)

CHARACTERIZATION OF YTTRIA AND MAGNESIA PARTIALLY STABILIZED ZIRCONIA BIOCOMPATIBLE COATINGS DEPOSITED BY PLASMA SPRAYING

Zirconia (ZrO₂) is a biocompatible ceramic material which is successfully used in medicine to cover the metallic implants by various methods. In order to avoid the inconvenients related to structural changes which may appear because of the temperature treatment while depositing the zirconia layer over the metallic implant, certain oxides are added, the most used being Y₂O₃, MgO and CaO. This paper presents the experimental results regarding the deposition of yttria (Y₂O₃) and magnesia (MgO) partially stabilized zirconia layers onto titanium alloy substrate by plasma spraying method. X ray diffraction investigations carried out both on the initial powders and the coatings evidenced the fact that during the thermal spraying process the structure has not been significantly modified, consisting primarily of zirconium oxide with tetragonal structure. Electronic microscopy analyses show that the coatings are dense, uniform and cracks-free. Adherence tests performed on samples whose thickness ranges between 160 and 220 μm showed that the highest value (23.5 MPa) was obtained for the coating of ZrO₂ - 8 wt. % Y₂O₃ with 160 μm thickness. The roughness values present an increasing tendency with increasing the coatings thickness.

Keywords: Plasma spraying, Stabilized zirconia, Coatings adherence