In vitro tribological investigation and osseointegration assessment for metallic orthopedic bioimplant materials Sachin Solanke a , Vivek Gaval b,⇑ , Sahil Sanghavi c a Department of General Engineering, Institute of Chemical Technology, Mumbai 400019, India b Faculty of General Engineering Department, Institute of Chemical Technology, Mumbai 400019, India c Knee and Hip Surgeon, Sancheti Institute for Orthopaedic & Rehabilitation, Pune, India article info Article history: Received 1 October 2020 Received in revised form 9 October 2020 Accepted 19 October 2020 Available online xxxx Keywords: Bioimplant materials Simulated body fluid Wear test Wear loss Apatite layer Adhesive strength abstract This research study is aimed at finding a suitable uncoated metallic biomaterial based on its wear prop- erties and osseointegration ability for orthopedic implants. In the present work, wear tests were carried out on uncoated metallic biomaterials such as Co-Cr-Mo, SS316L, Ti6Al4V and Titanium grade 2. The wear tests were performed to determine friction coefficient and wear loss in the presence of simulated body fluid having a common pH of 7.25 similar to human plasma. The wear resistance was found to be highest for Co-Cr-Mo material followed by SS316L, Ti6Al4V and Titanium grade 2 material. To grow an apatite layer, uncoated metallic substrates were immersed for two weeks in a simulated body fluid having ion concentration equivalent to human blood plasma. Adhesive bonding strength of the apatite layer formed on the different bioimplant substrates was evaluated under tensile stress. The worn metallic surfaces post wear tests and metallic substrates with apatite layer were analyzed using scanning electron micrographs. From the results it was found that uncoated Ti6Al4V material is more suitable for orthopedic implants as compared to other materials studied in this work. Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Confer- ence on Advances in Materials Processing & Manufacturing Applications. 1. Introduction From the literature survey it is clear that in the present scenario total hip and knee arthroplasty replacement is most common orthopedic surgery performed throughout the world. It was reported in the literature that total hip and knee replacement would increase by 175% and 674% respectively between 2005 and 2030 [1,2]. Near about five lakh and more hip and knee joint surgery replacement are being performed per year in the world [3]. The short life span of modern artificial bioimplant joint or arthroplasty is major drawback in current scenario, so researchers are trying to improve lifespan of artificial bioimplant joints. Gener- ation of wear debris due to articulating movement of components in the implanted metallic arthroplasty leads to the aseptic lessen- ing [4]. As a result, longevity of artificial arthroplasty would decrease and becomes unstable [5]. It was reported that 75%-85% artificial prostheses were made from metal alloys [6]. Several types of orthopedic implant biomaterials and alloys with their physical and chemical characteristic are being studied pertaining to biomedical field. Out of this only a few biomaterials are presently used for orthopedic bioimplant surgery. For bone replacement the most commonly used metallic biomaterial are titanium, stainless steel and cobalt-chromium alloys. Metallic biomaterials for ortho- pedic implants should have good mechanical properties such as high strength, high fracture toughness and high wear resistance. [7,8]. The wear property is important as far as metallic bioimplant functioning and performance in length of service is concerned. The release of metallic debris or ions due to wear in components of prosthesis leads to harmful or adverse effect in the human body. So high wear resistance becomes primary requirement of metallic bioimplant materials. In recent years short life and inadequate per- formance of artificial prosthesis has been associated to a phe- nomenon called stress shielding effect [9]. The stress shielding is caused due to mismatch of elastic modulus between artificial and natural bone. Elastic modulus of cortical bone is generally in the range of 15–25 GPa [10,11]. Stress shielding effect can be min- imized by selecting metallic biomaterial with an elastic modulus similar to human natural bone [12]. Torsional stiffness and modu- lus of elasticity of titanium alloys is comparable less than other https://doi.org/10.1016/j.matpr.2020.10.528 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Advances in Materials Processing & Manufacturing Applications. ⇑ Corresponding author. E-mail address: vr.gaval@ictmumbai.edu.in (V. Gaval). Materials Today: Proceedings xxx (xxxx) xxx Contents lists available at ScienceDirect Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr Please cite this article as: S. Solanke, V. Gaval and S. Sanghavi, In vitro tribological investigation and osseointegration assessment for metallic orthopedic bioimplant materials, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.10.528