This paper presented a new route of producing coating onto a mild steel substrate called �Silicanizing� by using natural silica sand originated from Tronoh Silica Sand (TSS) at elevated temperatures. Influence of the silicanizing process parameters especially temperature and time on the silicanized coating layer�s microstructure and mechanism were studied. Formation of Fe-SiO2 via interdiffusion of Fe and SiO2 were determined by the rate of grain boundary diffusion of SiO2 through the growing Fe-SiO2 phase shown at Silicanizing process temperature of 1000 °C for 4 h. Relevant silicanizing mechanism and chemical reaction involved in transforming TSS particles into thin film silicanized-coating on mild steel substrate is expected to be established. © Springer Nature Singapore Pte Ltd. 2020.