Corrosion behaviour of ZrN/Ti ceramic solid solution in fluids simulating biological inflammatory conditions

When an implant is inserted into a living tissue, the response of the organism is always associated with an inflammatory process caused by the surgical intervention and/or the foreign materials. Therefore, for the evaluation of the biocompatibility, it is important to investigate the behaviour of materials under such conditions. In the current study the corrosion behaviour of a ZrN/Ti (ZNT) ceramic solid solution under inflammatory conditions was investigated and compared with CP Ti. The ZNT ceramic material was prepared by hot pressing and the presence of tita-nium in the solid solution showed some beneficial effect on sinterability and on me-chanical properties, mainly hardness, if compared to monolithic ZrN. A phosphate buffer saline (PBS) solution (pH 7.4) and a PBS/0.1M H2O2 (pH=4) solution were used to simulate the body fluids in the absence and in the presence of inflammatory conditions respectively. The corrosion behaviour of the materials was monitored by linear polarization resistance measurements and polarization curves for two weeks. After the first week the PBS/H2O2 solution was replaced by fresh PBS solution in order to simulate the normalization process after the acute inflammatory phase. The behaviour of the tested materials under inflammatory conditions was compared with that in the absence of an inflammatory process. For ZNT solid solution exposed to inflammatory conditions the results showed a better corrosion behaviour than that observed on CP Ti, as an effect of the formation of a more protective surface oxide layer. The electrochemical results and the mechanical properties of ZNT ceramic material suggest that it is a promising candidate for biomedical applications where high corrosion and wear resistance are required