BIOCOMPATIBLE MATERIALS BASED ON HIGH-ENTROPY ALLOY CARBIDES, FOR COATING MOBILE COUPLINGS OF ARTICULAR ENDOPROSTHESES AND MEDICAL INSTRUMENTS

摘要

The invention relates to materials made of biocompatible thin layers applied as corrosion-resistant single layers adhering to the substrate, having low wear rate, meant to coat the mobile coupling of metal articular endoprostheses, as well as medical instruments and devices. According to the invention, the materials comprise high-entropy alloy carbides described by the general formula (EE...E)C where E...Eare metallic elements of the series Ti, Zr, Nb, Ta, Hf and Eis Si, in approximately equal atomic concentrations c, with a quasi-stoichiometric composition 0.9 ≤ c/( &Sgr;c) ≤ 1.1, the applied layer having the following characteristics: total thickness ranging between 2...4 μ m, average roughness 10 nm, micro hardness ranging between 22...31 GPa, the normal critical forces measured upon the scratch adhesion test having values which range between 38...48 N, exhibiting a friction coefficient 0.2 in Ringer's solution, at 37°C, having a wear rate ≤ 4 x 10mmNm, a corrosion rate ≤ 6 x 10mm/year and a value of the cell viability factor upon the toxicity test ranging between 88...96%.