Study of tribological characteristics of micro-arc calcium phosphate coatings on titanium

Abstract

Tribological characteristics of implants, such as wear resistance and friction coefficient, play a critical role in ensuring their durability and functionality when interacting with surrounding tissues. These parameters influence the implant's ability to withstand mechanical loads and minimize wear throughout its service life. Minimizing friction between the implant and biological tissues not only helps prevent mechanical damage but also reduces the risk of inflammatory reactions, ensuring better biological compatibility. In this study, calcium phosphate coatings were obtained using the micro-arc oxidation method with different duty cycle of current to investigate their tribological characteristics. The coatings deposited on titanium had a structure with volcano-like formations with pores ranging from 66 to 98 micrometers. The thickness of the coatings varied from 74.3 to 100 micrometers depending on the conditions during microarc oxidation. Tribological tests were conducted using a ball-on-flat setup with reciprocating motion. The coatings were subjected to tribological tests against SHX15 steel under normal loads of 5 and 20 N. Depending on the applied load, the friction coefficients of the coatings ranged from 0.029 to 0.034 at 5 N and from 0.9 to 1.26 at 20 N. Analysis of wear parameters and micrographs of worn surfaces indicate that the mode with a pulse current duty cycle of 17.3% during micro-arc oxidation allows for the production of titanium surface coatings with high wear resistance.