Comparative study on tribological and corrosion protection properties of plasma sprayed Cr2O3-YSZ-SiC ceramic coatings. Issue 17 (1st December 2019)

• Record Type: Journal Article
• Authors: Hashemi, S.M.; Parvin, N.; Valefi, Z.; Alishahi, M.
• Is Part Of: Ceramics international. Volume 45:Issue 17(2019)Part A
• Page Start: 21108
• Page End: 21119
• Publication Date: 2019-12-01
• Subjects: Cr2O3-YSZ-SiC -- Ceramic matrix composite -- Thermal spray coating -- Tribological/corrosion behavior -- Multimodal/nano; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2019.07.087
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: In this research, the tribological and corrosion protection properties of atmospheric plasma sprayed Cr2 O3 -20YSZ (CZ) and Cr2 O3 -20YSZ-10SiC (CZS) composite coatings on 304 L stainless steel substrates were evaluated and compared to pure Cr2 O3 (C) coating. Microstructural evaluations were carried out using an optical microscopy, X-ray diffraction (XRD) analysis, and a Field Emission Scanning Electron Microscopy (FE-SEM) equipped with Energy Dispersive X-ray Spectroscopy (EDS). The ball-on-disk wear test was performed using an alumina counterpart at room temperature. The protective efficiency of the coatings with/without sealing treatment was evaluated by electrochemical potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in a 3.5 wt% NaCl solution. Evaluation of wear tracks showed that enhancement of the wear resistance of the composite coatings was ascribed to the zirconia phase transformation toughening and the presence of more ductile tribofilms participated in pore filling during the wear. The corrosion measurements revealed that the protection properties of the coatings were strongly dependent on the porosity content so that the as-sprayed coatings due to their porous nature could not protect the substrate. However, filling the porosity using an epoxy sealant prevented the penetration of the corrosive environment into the substrate and therefore increased the protective efficiency of the coatings. Moreover, the density of the unfilled defects such as micro-cracks determines the protection properties of the sealed coatings, so that the CZ coating due to its highest toughness had the lowest micro-crack density and thus the highest protective efficiency.