Investigation of the morphological, structural, in vitro corrosion and bioactivity properties of cerium CE) incorporated bioceramic coated scaffold structures.

This study focused on the fabrication of porous Ti64 scaffold alloys using Ti64 alloy powder and spherical carbamide space holder particles by powder metallurgy method and the development of CeO2-HAp based bioceramic coatings on these scaffolds by sol-gel dip coating method. The coatings were applied using HAp and HAp with different weight percentages of CeO2 (1%, 5% and 10%). The morphological, structural, corrosion resistance, in vitro degradation, ion release and bioactivity properties of the reference and coated samples were investigated. Scanning Electron Microscopy (SEM) analyses revealed successful coatings using the sol-gel dip coating technique. However, microcracks were observed due to the high porosity of the surfaces. Three-dimensional optical profilometer analysis showed that the surface roughness decreased with the application of the HAp coating. Furthermore, characterisation by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) revealed the presence of elements, homogeneous crystal phase distribution and phase integrity. Microhardness values of both uncoated and coated scaffolds were measured, with CeO2 reinforced HAp coatings showing higher hardness values than those coated with only HAp.In vitro corrosion analyses showed that the porosity of the Ti64 alloy reduced its corrosion tendency. In addition, CeO2/HAp coatings increased the corrosion resistance, but it was observed that the corrosion resistance decreased at the 10% CeO2 level due to the high concentration. In samples immersed in simulated body fluid (SBF) for four weeks, the CeO2 content did not directly affect the degradation. Ion release analysis performed with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) showed no significant correlation between CeO2 content and ion release, suggesting that the ion release rates could be clarified with longer-term immersion tests. SEM-EDS analyses before and after the bioactivity tests indicated that the porous Ti64 surface without coating exhibited enhanced bioactivity compared to bulk Ti64. Furthermore, HAp coatings showed a distinct bioactivity advantage, while CeO2 doping, particularly at the 10% level, negatively affected bioactivity.