Influence of the electrochemical anodization on the surface roughness of Ti-13Nb-13Zr medical alloy

Abstract

Surface roughness is one of the influencing factors on the friction and wear mechanism of metallic materials. However, surface roughness of metallic biomaterials plays a major role in assessing the biocompatibility and adhesion of human cells of the surrounding bone tissue on the biomaterials surface. Namely, it is already known that as the surface roughness increases, contact surface with human cells increases, and thus their adhesion to the surface. In order to achieve adequate roughness and biocompatibility, it is often necessary to additionally subject the surface of the biomaterial to modification. In the present study, nanostructured oxide coating on the Ti-13Nb-13Zr alloy was formed by electrochemical anodization in the 1M H3PO4 + NaF electrolyte, during 60, 90, 120 minutes. The scanning electron microscopy (SEM) was used to analyse the nanostructured oxide coating morphology and showed that highly ordered nanotubular oxide layers were formed by electrochemical anodization. The atomic force microscopy (AFM) was used to characterise the surface topography before and after electrochemical anodization. Results showed that the surface had higher roughness after electrochemical anodization compared to initial surface of the alloy. It was also shown that increase of anodizing time induces increase of the surface roughness.