Abstract: To improve the combustion and fire- extinguishing performance of hot aerosol extinguishing agents (HAEAs), a new type of HAEA was prepared by freeze-drying co-crystallization process in this paper. Eight groups of HAEAs with an increasing mass ratio of 45% ~ 60% potassium nitrate and a decreasing mass ratio of 55% ~ 40% lactose were co- crystallized and compared with the mechanically mixed HAEAs of the same composition and proportion. The results of fire- extinguishing performance test show that the co- crystallization process can significantly shorten the extinguishing time of the HAEAs. The fire- extinguishing effect was best when the ratio of potassium nitrate to lactose was 4.75:4.25, and the fire-extinguishing time was shortened from 6.91s to 1.00 s. The co- crystallized products were characterized by scanning electron microscope (SEM), thermal analysis (TG/DSC), powder X- ray diffraction (PXRD), and Fourier transform infrared reflection (FTIR). The results indicated that there were co-crystallized products different from raw materials.

Key words: co- crystallization, hot aerosol extinguishing agent, extinguishing efficiency