Synergistic effect of nano hybrid multi-layered graphene oxide/talc and silica fume on the fire and water -resistance of intumescent coatings

Abstract

In this study, the synergistic effect of silica fume and nanohybrid multi-layered graphene oxide/Talc (MLGO/Talc) was investigated in improving the moisture and fire resistance properties of an intumecsent fire retardant (IFR) coating on steel substrate. Furnace test, Cone Calorimetry (CC), Limiting Oxygen Index (LOI), salt spray, humidity, pull-off, Scanning Electron Microscopy-Energy Dispersive X-ray Analysis (SEM-EDAX) and Thermogravimetric Analysis (TGA) were used for coatings evaluations. Based on the results of cellulose fire resistance tests, the resulting IFR coating delayed the time to reach the critical temperature of 550 °C for 45 min. The SEM and pull-off results showed that the uniform distribution of the optimal amount of MLGO/Talc (1 wt%) increased the formed char strength and its adhesion to the substrate. Also, increasing the optimal amount of silica fume (10 wt%) resulted in the formation of a continuous, compact and uniform char. The results of the TGA test showed that the oxidation resistance of the formed char was higher compared to other coatings due to heat blocking by the Si-O-Si network. According to the results of the salt spray test, the resulting IFR coating showed good adhesion and corrosion resistance after 1000 h, and after 550 h of the humidity test, no blisters were observed on the coating surface. After 550 h of humidity test, the fire resistance of the coating decreased for only 6 min.