The Effect of Expandable Graphite and Zinc Borate on Performance of Intumescent Fire Retardant Coating

Expandable graphite (EG), ammonium polyphosphate, melamine, epoxy resin and zinc borate coating were prepared. Char expansion and char structure of the coating were investigated by using Scanning Electron Microscopy (SEM). The results have shown that the anti-oxidation and fire-resistant properties of coating No 8 and coating No 13 are better than the other 12 formulations. Fire test by using furnace and Bunsen burner were done to check the char expansion and the char structure. During furnace test, coating No 8 and coating No 13 shows five and four times of expansion respectively. The back temperature of mild steel plate of coating No 8 is 287 oC and coating No 13 is 253 oC. Both char are observed to have rough surface, hard and not detached from the substrate. Both coatings have good char structure and fire protection properties even after exposed to temperature of 450 oC.