In-situ synthesis of MoSi2 coating on Mo substrate under carbon protection and its short-term oxidation behavior

Abstract

MoSi2 coating was in-situ synthesized on pure Mo substrate by a simple and improved packing method, in which carbon powder was used for providing a protective atmosphere. The microstructure and phase composition of the coated samples were characterized by SEM, EDS and XRD techniques. The mechanism of coating preparation was discussed. Results showed that the addition of carbon could effectively protect Mo from oxidizing during the coating preparation. A compact MoSi2 coating with a loose surface layer was obtained. It was suggested that the trace oxygen availed the formation of the compact internal structure and the loose surface layer. And this particular coating structure was expected to contribute to a better oxidation resistance in high temperature. Additionally, the short-term oxidation behavior of the as-prepared MoSi2 coating was investigated. The as-prepared MoSi2 coating provided an unexceptionable protection for the Mo substrate from oxidation at 1600 °C for 1 h. The presence of a glassy silica layer that formed on the MoSi2 coating during the oxidation exposure was proposed to explain the behavior. It shows the simple and improved packing method with carbon powder as protective medium is promising potential for the preparation of various anti-oxidation coatings.