Effect of AlTaO₄/APP synergistic action on fire-retardancy and smoke-release of epoxy resin composite coatings

A brand-new fireproof coating (EP1-EP5) was prepared by co-mingling. Here, fire test results show EP5 coating on Q235 steel has a significant cooling gradient (similar to 843 degrees C) derived from the synergistic effect of AlTaO4 and APP (ammonium polyphosphate). Compared with epoxy resin, the EP5 coating substantially reduced the peak heat release rate (PHRR) and the peak smoke production rate (PSPR) by 85.9 % and 85.1 %, respectively. Furthermore, the combustion dramatically lowered CO and CO2 emissions by 80.6 % and 76.5 %, respectively. This study supports the notion that combining AlTaO4 and APP helps develop a dense, stable, and continuous char layer, which effectively retards the burning rate of epoxy, thereby reducing fire risk. Additionally, the reaction products (Al2O3 and AlPO4) of AlTaO4 and APP as an enhancement phase improve the oxidization resistance of the char layer in the high-temperature process. Hence, the combined influence of AlTaO4 and APP favors the flame retardant and smoke inhibition capabilities of fireproof coatings. This finding presents a straightforward and efficient approach to advancing the development of fireproof coatings.