Study on Mechanical Properties and Electrochemical Corrosion Resistance of Arc Sprayed FeAlMoNbCrC and FeAlMoNiCrC Coatings

Abstract

The FeAlMoNbCrC and FeAlMoNiCrC coatings are fabricated on the surface of pretreated 45 steel via high-velocity arc spraying technology. Microstructure, mechanical properties and electrochemical corrosion resistance of the coatings are systematically investigated. Results revealed that coatings are composed of intermetallic compounds and oxides, exhibiting a typical compact lamellar stacking structure with controlled porosity ranging from 5 to 10%. The hardness of FeAlMoNbCrC and FeAlMoNiCrC coatings is increased compared with the 45 steel by 109.85 and 58.13%, respectively. FeAlMoNbCrC and FeAlMoNiCrC coatings exhibit wear coefficient of 45.33 and 53.56 μm³/mm N, respectively, with a friction coefficient ranging from 0.6 and 0.8. The dominant wear mechanism observed in these coatings is abrasive wear characterized by slight plastic cutting and brittle spalling of hard phases. The electrochemical corrosion resistance of FeAlMoNbCrC and FeAlMoNiCrC coatings surpasses that of 45 steel, as evidenced by self-corrosion potentials of − 0.8205 and − 0.6385 V, along with self-corrosion currents of 1.0083 × 10⁻⁴ and 6.382 × 10⁻⁵ A/cm², respectively. The enhanced electrochemical corrosion resistance can be attributed to the presence of Cr which facilitates the formation of oxide films within the coatings. Lastly, an analysis is conducted on the evolutionary mechanism underlying passivation film failure during overpassivation.