Functional element coatings on Ti-alloys for biomaterials by plasma electrolytic oxidation

Abstract

In this study, functional element coatings on Ti-alloys for biomaterials by plasma electrolytic oxidation (PEO) were studied using different experimental techniques. Si- and Mg-doped hydroxyapatite films were formed on the Ti–6Al–4V alloy via anodization at an applied DC voltage of 280 V for 3 min. The chemical composition of the surface layers was examined using energy-dispersive X-ray spectroscopy mapping and line-profile analysis. The morphology of the surface was observed using field-emission scanning electron microscopy. The phase composition was determined using X-ray diffraction. The size of the micro-pore formed on the Ti–6Al–4V alloy decreased, and the area occupied by the micro-pores decreased with increasing Mg concentration. With the increase in Mg concentration, the number of small micro-pores on the PEO films formed on Ti–6Al–4V alloys increased, whereas the number of large micro-pores decreased. The number of circular particles formed in the pores and on the exterior surface increased with increasing Mg concentration. The thickness of the PEO film was approximately 1.94–2.03 μm and the coating elements Ca, P, Si, and Mg were uniformly distributed throughout the PEO film. The anatase and hydroxyapatite(HA) peaks shifted slightly from the original anatase and pure HA peaks as the Mg concentration increased.