Volume 44, No 1, 2022, Pages 97-112
Effect of Varying Stand-off Distance on Tribological and Mechanical Properties of Plasma Sprayed Hydroxyapatite Coated Metallic Substrates
Received: 13 February 2021
Revised: 27 April 2021
Accepted: 2 June 2021
Published: 15 March 2022
Plasma spray technique is commonly used for the fabrication of hydroxyapatite (HA) coating for bio implants. Out of various process parameters in plasma spray technique, stand-off distance is one of the most important parameter which affects tribological and mechanical properties of the substrate. In the present work, HA powder was plasma sprayed onto Titanium grade 2 and Titanium grade 5 metallic substrates by varying standoff distance. Wear test was carried out to determine coefficient of friction and wear weight loss in the presence of simulated body fluid having a common pH of 7.25 similar to human blood plasma. The scanning electron microscopy and X-ray diffraction were used for characterization of microstructures and phase composition of coating respectively. Results have shown that HA coating obtained at 230 mm stand-off distance exhibits hardness and anti-wear characteristics as compared to coatings with stand-off distance of 180mm and 280 mm. This may be attributed to lower porosity and dense structure at a stand-off distance of 230 mm. The main wear mechanisms on the coating’s wear track were found to be abrasive and adhesive.
Plasma sprayed hydroxyapatite coating, Stand-off distance, Microstructure, Sliding wear in Simulated Body Fluid, Mechanical properties