Long-term steady state friction and wear rate estimation of ZTA against AZ31 alloy under different bio-lubricants for hip prosthesis - an in-vitro study

The present study focuses on in-vitro bio-tribological study of ZTA against AZ31 alloy, in estimating friction and wear rate for long-term sliding distance of 40 km using Ball-on-Disc (B-o-D) tribometer for human hip prosthesis. The bio-lubricants considered for current study includes saline solution, Ringer's solution, distilled water, phosphate buffered saline (PBS) and sesame oil with B-o-D load of 20 N. Sesame oil exhibited least coefficient of friction (CoF) of 0.35 and maximum CoF of 0.42 is obtained for saline solution. Later, wear rate of ZTA is obtained for all these bio-lubricants and found that sesame oil exhibited least wear rate (K) of 8.55 × 10-6 mm3/Nm and maximum (K) of 1.25 × 10-5 mm3/Nm obtained for saline solution. The scanning electron microscope (SEM) micrograph depicted the mechanism behind these wear behaviour under different bio-lubricants, which revealed that, formation of tribo-film under sesame oil bio-lubricant medium could improve longevity of implants.