Magnesium (Mg) ions were incorporated into fluoridated hydroxyapatite (HA) coating by the sol-gel dip-coating method. Mg in the coating was measured by x-ray photoelectron spectroscopy (XPS). The changes of calcium and magnesium concentrations were recorded to monitor the dissolution behavior of the coatings. In vitro cell responses were evaluated using MG63 cells in terms of cell morphology, proliferation and differentiation. The substitution of Mg and F ions into the HA crystal structure was confirmed by XPS. Only a limited amount of Mg can be incorporated into HA lattice. The dissolution test revealed that Mg incorporation increased the solubility of the coating in the tris-buffered saline solution. The highest solubility was achieved at x = 1.5 (Ca((10-x))Mg(x)(PO(4))(6) F(OH). In the cell culture test, well-spread cells were observed on all the coatings. Also, a significantly positive effect of Mg ions on cell proliferation and late differentiation was found at x = 1.5. Mg incorporation stimulates osteoblastic cell responses on fluoridated hydroxyapatite coatings.

Plasma spraying is a well established technique for many industrial applications. In the present study, plasma sprayed Al 2 O 3 z13 wt-%TiO 2 coatings with bond layer of NiCrAl were prepared and characterised by optical microscopy, scanning electron microscopy and X-ray diffraction. Silicone resin sealing treatment was applied to the coating, and the salt spray test and electrochemical testing were conducted to investigate the effect of the sealant on the corrosion resistance of the coatings. It was found that the sealants filled the pores and microcracks in the coating and formed a thin layer with the ceramic, protecting the substrate from corrosion, while the as sprayed coating was subjected to pitting corrosion in the form of electrochemical corrosion at the interface between the bonding layer and the substrate.