Study and Characterization of Mechanical and Electrochemical Corrosion Properties of Plasma Sprayed Hydroxyapatite Coatings on AISI 304L Stainless Steel

Abstract

The use of hydroxyapatite coatings is limited by their inferior mechanical properties such as brittle nature, low wear resistance, abrasion, fatigue, and hardness. This ultimately leads to the wear and early rupture of the hydroxyapatite coating on the implant. The main objective of this study is to improve the mechanical properties of hydroxyapatite by using additional reinforcement material such as alumina (Al2O3). The HAp powder has been reinforced with 15wt% Al2O3and its effect on the properties of HAp coatings has been studied. The HAp and HAp +15 wt% Al2O3coatings were deposited on AISI 304 L SS substrates using the plasma spraying technique. The morphology of the coatings developed was characterized using SEM/EDX, XRD, and FTIR techniques. The corrosion resistance studies have been performed on uncoated and coated samples and found that HAp coated samples show superior resistance against corrosion (ICorr= 0.538 μA) than uncoated (ICorr= 3.550 μA) and HAp+15 wt% Al2O3coated (ICorr= 1.440 μA) samples when electrochemical corrosion studies were performed in Ringer’s solution. Surface roughness and microhardness were found to increase with the addition of Al2O3. Crystallinity (%) of the HAp coatings and HAp+15 wt% Al2O3coatings increases after the corrosion testing.