Plasma surface modification of degradable magnesium alloy and non degradable stainless steel: enhanced corrosion resistance, antimicrobial properties, cytocompatibility and covalent immobilization of protein molecules

Abstract

Surface modification is the viable approach to improve the surface properties of the biomaterials. Plasma treatments used in this thesis are plasma ion implantation, cathodic arc deposition and plasma assisted chemical vapor deposition (PACVD) which is explained detail in chapter (c) 1. Mg alloys possess good mechanical properties and degrades in physiological environment which makes them attractive biodegradable biomaterials. However, their degradation rate is rapid. In c 2, we investigate the corrosion behavior of WE43 and ZK60 Mg alloys in Ringer's solution and simulated body fluids (SBF). Ca10(PO4)6(OH)2, Ca3(PO4)2⋅3H2O, and Mg(OH)2 are predominant corrosion products formed on both Mg alloys in SBF whereas crystalline aragonite form of CaCO3 and Mg(OH)2 dominate in Ringer’s solution. In c 3, we investigate the corrosion resistance of WE43 Mg alloy after Si plasma ion implantation. In c 4, we investigate the corrosion behavior of WE43 Mg alloy in SBF and cell culture medium after Zr&N implantation. In c 5, we investigate the corrosion resistance of ZK60 Mg alloy after Zr&O implantation. In c 6, we investigate the corrosion resistance, cytocompatibility, and antimicrobial activity of Mg–Ca and Mg–Sr alloys after Zr&O implantation. In c 7, we investigate the corrosion resistance of Mg–Nd–Zn–Zr alloy after C2H2 implantation. The corrosion resistance of Mg alloys in physiological environment are improved after Si, Zr, Zr&O, Zr & N, C2H2 implantation. Zr&O implantation enhanced the cytocompatibility, and antimicrobial properties of Mg–Ca and Mg–Sr alloys. Stainless steel is used in implants. However implant materials subject to adverse responses because of the weak interaction with the protein molecules. In c 8, we demonstrated that the deposition of a Ti&C composite graded film by hybrid cathodic arc/glow discharge PACVD. Strong adhesion was achieved between the metal surface and the deposited layers. Graded film exhibited strong adhesion with protein molecules.