Structure and Properties of the SiO₂–Cr₂O₃ Coatings Obtained by Pulsed Magnetron Sputtering onto a ZrO₂ Ceramic Substrate

A technique for obtaining SiO₂–Cr₂O₃ coatings on a Y-TZP (ZrO₂ stabilized by Y₂O₃) zirconia ceramic substrate is proposed. The coating has been created in three stages: (i) forming a SiO₂ adhesion layer by applying a 5% solution of 3-aminopropyltriethoxysilane alcohol onto the ceramic substrate surface with the subsequent heat treatment at 450 ± 5°C for 30 min, (ii) deposition of Cr (purity 99.9%) by pulse magnetron sputtering onto the prepared ceramic substrate with the formed SiO₂ layer, and (iii) diffusion oxidation of Cr deposited onto the ceramic substrate to Cr₂O₃ in a muffle furnace at a temperature of 450 ± 5°C for 30 min. The mechanical characteristics of the coating have been examined depending on the preliminary and finishing operations (abrasive-jet machining and polishing). Samples with the coating of a submicron thickness of 150 ± 20 nm having the lamellar nanostructure, an open porosity value of 1.3%, a microhardness of 2000 HV, roughness Ra of 0.32–0.63, a friction coefficient of 0.175, and an abrasion resistance against loadings 184% higher than for pure zirconia ceramics have been obtained.