Abstract: The focus of this article is to synthesize new formulations of intumescent coatings with improved fire resistance of steel structures. The coating formulations are based on wollastonite and bentonite - reinforced expandable graphite. Ten types of intumescent coating formulations are formulated based on the content of wollastonite and bentonite and different grinding times . The test results show that as the filler (wollastonite and bentonite) content and grinding time increase, the carbon expansion rate increases, and at the same time, it can reduce the thermal penetration of the heat source to the steel plate substrate. X- ray diffraction (XRD) analysis shows that the residual carbon contains aluminum borate, which has high thermal stability and can enhance the fire resistance of the coating. With the increase of filler content and grinding time, the carbon content in the residual carbon increases, the oxygen content decreases, and the phosphorus content increases. A higher proportion of phosphorus can help increase the formation of carbonaceous carbon. Higher filler content and grinding time can increase residual weight and fire resistance.

Key words: wollastonite;bentonite, intumescent fire - retardant coatings, fire resistance analysis