Suppression on heat and smoke diffusion by zirconium nitride (ZrN) in intumescent flame retardant epoxy coatings

Abstract

In order to control heat and smoke release of the intumescent flame retardant (IFR) epoxy coating on steel during fire hazard, a little amount of zirconium nitride (ZrN) of 1～3 wt% was introduced into the coating. The back temperature test showed it used about 46.1 min for the steel plate coated with IFR coating without ZrN to reach 580 °C, however by using of 3 wt% ZrN, the time was prolonged to 61 min, indicating the steel structure can be kept for more than 15 min. The result is very important to the safety of steel structure, meaning more escape time during a fire hazard. Furthermore in cone test, the coating containing ZrN exhibited more control on heat and smoke release. For example, compared with the IFR coating containing no ZrN, coating containing 3 wt% ZrN cut more than 20.3% total heat release (THR) and 40.0% smoke production (SPR).The graphitization degree increase of char was documented by Raman spectrum; and in XRD patterns some special peaks of ZrP2O7 and Ti0.8Zr0.2P2O7 was found in char, all the results indicated ZrN participated into the charring with IFR and TiO2 together and then promote formation of more compact char structure.