In this research, the surface properties of knee implants were investigated an‎d improved with the aim of reducing wear, corrosion, an‎d metal ion release. In recent years, with the increasing average age of the population, the occurrence of knee-related problems has risen significantly, leading to a growing need for knee implants. The implants commonly used today are made of stainless steels, cobalt–chromium–molybdenum alloys, an‎d titanium alloys. Among these, knee implants are most often fabricated from cobalt–chromium alloys.However, the use of knee implants is generally associated with complications such as implant loosening, inflammatory diseases, an‎d allergic reactions caused by the wear that occurs between the metal component an‎d the polymer (ultra high molecular weight polyethylene). This latter issue results in greater release of cobalt an‎d chromium ions. Wear behavior is influenced by the implant manufacturing process an‎d the surface structure of the implant. Due to the presence of carbon in the cobalt–chromium alloy, hard carbides precipitate within the material, which, despite enhancing hardness, create microscopic protrusions on the surface of the final prosthesis. These surface carbides lead to increased wear of the softer articulating surface (UHMWPE).One of the effective ways to mitigate surface wear is the application of protective coatings. In recent years, coating the surface of implants has significantly reduced wear related issues an‎d improved surface properties such as hardness, wear resistance, friction coefficient, an‎d metal ion release. Among various coatings, nitride based coatings particularly zirconium nitride coatings have found wide application in this industry due to their excellent properties, including high biocompatibility, wear resistance, hardness, an‎d corrosion resistance. These coatings are typically deposited using physical vapor deposition (PVD) techniques.Nevertheless, the deman‎d for superior surface performance has led to the development of high entropy nitride coatings, which exhibit enhanced wear resistance, corrosion resistance, an‎d mechanical properties compared to conventional nitride coatings.The aim of this study is to deposit an‎d eva‎luate the microstructure, mechanical, corrosion, an‎d biocompatibility properties of the high entropy (TiZrNbCuSi)Nx coating. In this work, both zirconium nitride based an‎d high entropy (TiZrNbCuSi)Nx coatings were deposited on cobalt–chromium–molybdenum substrates using the physical vapor deposition process. The crystal structure an‎d microstructure of the coatings were examined by X-ray diffraction (XRD) an‎d field emission scanning electron microscopy (FESEM). Surface topography was characterized using atomic force microscopy (AFM). Furthermore, the mechanical an‎d corrosion behaviors of the coatings were eva‎luated using nanoindentation an‎d potentiodynamic polarization tests.The results demonstrated that the high entropy (TiZrNbCuSi)Nx coating exhibited a significant improvement in hardness, corrosion resistance, an‎d wear resistance compared to the zirconium nitride based coating.

عباس بهرامي , مهران نحوي

مسعود عطاپور , رحمت اله عمادي