Migration and enrichment of chromium and silicon element in glass coating at high temperature

The formation and mechanism of chromium and silicon enriched glass coating on carbon steel substrate were investigated in this paper, which was based on the protection properties of the glass coating to improve the anti-oxidation ability of carbon steel. The starting reaction temperature between the glass coating and steel substrate was 800 °C, which was approved by TG-DTA test. The diffusion of chromium and silicon element in glass coating was investigated at 800 °C and 1000 °C by WDS-EPMA and SEM-EDS. It indicated that chromium element began to migrate to interface between glass coating and carbon steel at 800 °C and a chromium enriched layer formed when the sample was heated at 800 °C for 60 min. Meanwhile, a silicon enriched layer started to form at the interface between glass coating and carbon steel at 1000 °C. The content of silicon element in the scale of coated sample increased with increasing heating time and which could reach up to 8.08% when the sample was heated at 1000 °C for 30 min. The sample was also characterized by XRD, SEM-EDS and Raman to investigate the possible phases formed during high temperature treatment.