Electrochemical and structural characterisation of zirconia reinforced hydroxyapatite bioceramic sol-gel coatings on surgical grade 316L SS for biomedical applications

摘要

Yttria-stabilized zirconia (YSZ)/hydroxyapatite (HAP) composite coatings on surgical grade 316L stainless steel was carried out using sol-gel dip coating and calcination process. Various molar ratios of HAP and YSZ was developed, each YSZ/HAP gel coating showed an average particle size of ～30 nm and the coatings were dried and calcined for crystallization. The functional group and crystallization characteristics of the coatings were analyzed using (FT-IR), X-ray diffraction (XRD) and energy dispersion X-ray analysis (EDXA). The formation of β-tricalcium phosphate (β-TCP) was controlled changing the Ca/P ratio in HAP phase and also YSZ content in the composite coatings. It was revealed that TCP content showed a very minimum value at Ca/P ratio of ～1.67 and at YSZ content of 30 vol.%, respectively. The mechanism of increased β-TCP content with Ca/P ratio lower than 1.67 and increased YSZ content was explained as Ca-deficiency due to the Ca-diffusion into t-ZrO{sub}2 crystals to form a solid solution. The resultant coatings were analysed for its corrosion resistance through polarisation, impedance and ICP-AES analysis in simulated body fluid. The viability of the reinforced coatings were analysed by in vitro cell culture studies.