Bioactive and Tribological Behaviour of Atmospheric Plasma Sprayed Hydroxyapatite Coatings Reinforced by Lanthanum Oxide

Lanthanum oxide (La2O3) reinforced Hydroxyapatite coating was deposited by using unique gas tunnel type plasma spray torch under optimum spraying conditions. The phase and microstructure of the as-prepared powder and coatings were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). In vitro bioactivity of the plasma sprayed lanthanum oxide reinforced hydroxyapatite coatings were investigated by using simulated body fluid solution. Results showed that there was onset of apatite formation on the surface of coatings after 15 days of immersion in SBF, while after 19 days of immersion in SBF it was indicated that a HCAp phase crystallized on their surface. Our studies demonstrate that lanthanum oxide reinforced hydroxyapatite coatings are potentially useful biomaterials with good tribological and bioactive behaviour

Characterization of gas tunnel type plasma sprayed hydroxyapatite-nanostructure titania composite coatings

Hydroxyapatite (HA) can be coated onto metal implants as a ceramic biocompatible coating to bridge the growth between implants and human tissue. Meanwhile many efforts have been made to improve the mechanical properties of the HA coatings without affecting its bioactivity. In the present study, nanostructure titania (TiO2) was mixed with HA powder and HA–nanostructure TiO2 composite coatings were produced by gas tunnel type plasma spraying torch under optimized spraying conditions. For this purpose, composition of 10 wt% TiO2 + 90 wt% HA, 20 wt% TiO2 + 80 wt% HA and 30 wt% TiO2 + 70 wt% HA were selected as the feedstock materials. The phase, microstructure and mechanical properties of the coatings were characterized. The obtained results validated that the increase in weight percentage of nanostructure TiO2 in HA coating significantly increased the microhardness, adhesive strength and wear resistance of the coatings. Analysis of the in vitro bioactivity and cytocompatibility of the coatings were done using conventional simulated body fluid (c-SBF) solution and cultured green fluorescent protein (GFP) labeled marrow stromal cells (MSCs) respectively. The bioactivity results revealed that the composite coating has bio-active surface with good cytocompatibility