Plasma Sputtering of Nano-CaTiO₃ Thin Film Applied for Surface Modification of Co–Cr Alloy

Abstract

A biocompatible and corrosion-resistant coating was progressed by depositing a thin film of calcium titanate (CaTiO[Formula: see text] on CoCr-based alloy substrate using a radiofrequency magnetron plasma sputtering process to improve the characteristics of the interface between the thin-film coating and the CoCr alloy substrate. In this technique, the best power was previously observed at 225[Formula: see text]W to get good coating film deposition properties. This power was applied to a deposited thin film of CaTiO3 on a heated CoCr-based alloy at [Formula: see text]C using an argon gas atmosphere with purity (99.8%) under vacuum 1.00E-02 Torr. Different deposition rates and times were used to observe nanofilm, the thicknesses of (50[Formula: see text]nm, 80[Formula: see text]nm, 110[Formula: see text]nm and 140[Formula: see text]nm). Field-emission scanning electron microscopy (FESEM) was applied to study surface morphologies. X-ray diffraction (XRD) was used to study the crystalline structure of thin films deposited. The Vickers Micro-Hardness tests were implemented on each specimen. Vitro electrochemical corrosion tests (open circuit potential, Tafel polarization curve and cyclic polarization) of the coated and uncoated specimens were done, to find the optimal state that gives excellent resistance to corrosion in a simulated body fluid environment. The results of the experiments showed that as the thickness of the thin films increased, so did the hardness measurements. An enhancement in corrosion resistance also was clearly observed at a thickness of 140[Formula: see text]nm CaTiO3 thin-film compared with uncoated and coated specimens at other nanothicknesses.