Spark plasma sintered Co-Cr-Nb ternary alloys for biomedical application

¹ Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria, South Africa
² Centre for Energy and Electric Power, Tshwane University of Technology, Pretoria, South Africa

^* Corresponding author: johnabe.fm@gmail.com

Abstract

The development of Co-Cr-Nb ternary alloys as prospective metallic biomaterials for clinical implants via spark plasma sintering was studied in this work. Optimized spark plasma sintering parameters were employed to fabricate the Co-Cr-Nb ternary alloys. The effects of Nb content on the nanomechanical, tribological, and electrochemical properties of the sintered alloys were considered. The results showed the presence of HCP (ε-Co) and FCC (γ- Co) cobalt phases in the microstructures of the ternary alloys, indicating that the addition of Nb stabilizes the mixture through alloying, resulting in a metastable coexistence of HCP and FCC phases. The densification of the ternary alloys depreciated slightly with increasing Nb concentration, likely due to inadequate powder mixing and increased contact regions. It was noted that the nanomechanical properties (hardness and elastic modulus) of the sintered ternary alloys ameliorated as the amount of Nb in the alloys increased. Besides, the ternary alloys showed enhanced wear resistance and superior corrosion characteristics over pure Co-Cr binary alloy as Nb content increased from 5 to 7 wt. %, respectively.