Tribological performance of Yttrium stabilized zirconia coatings on Ti6Al7Nb alloy in Hanks Balanced Salt

Abstract

Titanium alloy (Ti-6Al-7Nb) is the new trend among the bio-compatible alloys due to its non-cytotoxicity. In this work.Ti-6Al-7Nb is coated with 8YSZ powder coating using plasma spraying with NiCrAlY as the bond coat. The surface morphology, elemental composition, phase structure and micro hardness were investigated using FESEM, SEM, EDS, XRD respectively. To study the tribological wear behavior Taguchi methodology is employed. Pin-on-disc equipment is used conduct the experiment in Hanks' Balanced Salt Solution (HBSS) used as the lubricant in accord with ASTM G99 at room temperature. L16 Orthogonal array is chosen with the process parameters such as distance travelled (500, 1000, 1500 and 2000 m), velocity (0.3, 0.6, 0.9 and 1.2 m/sec), load (5, 10, 15 and 20 N) and coating thickness (100, 200, 300 and 400 µm). It is to be noted that there is no significant change in the hardness among the coated specimens but hardness increased from uncoated to the coated specimens. From the experiment it is concluded that distance is the most influential factor in assessing the coefficient of friction and coating thickness is the most influential factor influencing factor in assessing the weight loss.