A comprehensive study of microstructure, mechanical behavior, biocorrosion, and cytotoxicity of RF-PVD deposited Ti1.5ZrTa0.5Nb0.5X0.5 (X: Hf, Mo, and W) refractory high-entropy alloy films on 316L

In this study, Ti1.5ZrTa0.5Nb0.5Hf0.5, Ti1.5ZrTa0.5Nb0.5Mo0.5, and Ti1.5ZrTa0.5Nb0.5W0.5 refractory high-entropy alloys (RHEA) films were deposited on the 316L substrate using radio frequency physical vapor deposition technique (RF-PVD). The structural investigations revealed that deposited RHEA films had an amorphous structure with smooth morphology and granular features that were few to several hundred nanometers in size. The external surfaces of the deposited films were composed of constituent elements in their oxide and/or sub-oxide forms. The enhanced contact angle, hardness, tribological performance, adhesion and resistance to scratching, biocorrosion resistance, and low release of Ni and Cr ions demonstrated that Ti1.5ZrTa0.5Nb0.5W0.5 might be a suitable protective coating for 316L biomaterials. Additionally, the in vitro cytotoxicity assessment using C2C12 muscle myoblast cells revealed no cytotoxic response and good cell proliferation.