Tribological behavior of high-pressure torsion processed biodegradable pure Zn under dry and wet conditions

Abstract

Purpose Zn has been attracting increasing attention with its biological compatibility property as a degradable implant material. Besides mechanical properties, especially for bone implant applications, wear resistance is a crucial mechanical property. The purpose of this study is to investigate HPTed Zn samples' tribological behavior under dry and simulated body fluid (SBF) lubrication conditions. Design/methodology/approach Pure Zn powders were consolidated via the high-pressure torsion (HPT) method with 1, 5 and 10 rotations. Cast pure Zn samples were used as the control group. The wear behavior of pure Zn samples was investigated under dry and SBF lubrication conditions with a ball-on testing method. The wear tracks were observed with a mechanical profilometer and scanning electron microscope (SEM). Findings The application of HPT not only improved the mechanical strength and degradation performance but also improved wear resistance. However, tests with SBF resulted in higher wear rates. Besides, SBF significantly masked the positive effect of HPT on the coefficient of friction (COF). Although with SBF tests, 10 HPT rotation samples resulted in the lowest wear width and volume. Originality/value The main originality of this study is to reveal the HPT process and SBF effects on the tribological behavior of pure Zn to observe their potential usage for bone implant applications.