Impact of Rare Earth Particulates Addition on the Wear Rate of Magnesium Composites with Improved Mechanical and Microstructural Properties for Orthopedic Applications

Article Impact of Rare Earth Particulates Addition on the Wear Rate of Magnesium Composites with Improved Mechanical and Microstructural Properties for Orthopedic Applications Divyanshu Aggarwal 1,*, Siddharth Sharma 2 and Manoj Gupta 3,* 1 Department of Mechanical Engineering, Thapar Institute of Engineering and Technology, Patiala 147004, Punjab, India 2 Department of Biotechnology Engineering, Thapar Institute of Engineering and Technology, Patiala 147004, Punjab, India 3 Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore * Correspondence: [email protected] (D.A.); [email protected] (M.G.); Tel.: +91-8591093067 (D.A.); +65-166358 (M.G.) Received: 18 July 2024; 22 August 2024; Accepted: 30 August 2024; Published: 9 September 2024 Abstract: This study aims to evaluate the wear rate of Mg-Hydroxyapatite-based composites reinforced with rare earth oxide (Neodymium oxide) under in-vitro physiological conditions along with mechanical and microstructural evaluations. To analyze the wear rates of the composites, an innovative technique has been designed to perform experiments on the fabricated samples. The counter disc used for interaction was stainless steel disc coated with the same material as the samples. The analysis was performed under different loading conditions with different sliding velocities considering the different compositions of rare-earth oxide (1%, 1.5%, and 2%). The samples were fabricated via powder metallurgy route with compaction pressure of 250 MPa followed by sintering at 400 °C for 2 Hrs. Moreover, the mechanical analysis was done by calculating the samples’ microhardness and ultimate tensile strength. In contrast, the materials were characterized and synthesized employing FTIR, FESEM, XRD, and EDS techniques. The lowest wear rate was observed when the samples were subjected to higher load and lower velocities. Also, it was found that during progressive wear testing, the wear rate is maximum in the initial stage, but with the increase in sliding distance, the wear rate tends to reduce and then become steady. In addition, it was found that Mg-HA-1.5Nd2O3 showed the highest wear resistance. Moreover, the microhardness of the sample with a rare-earth concentration of 1.5% was higher as compared to other samples. Similar results were obtained for ultimate tensile testing of the composites. FESEM images showed refined microstructure of the samples, with EDS results showing the homogenous distribution of HA and REO particles. XRD analysis showed the development of secondary β-phases that interlocks grain boundaries. Hence, the designed experimental setup provides extensive wear rate results with related conditions created when the implant is placed inside the physiological environment.