Abstract: In order to explore the corrosion behavior of foam extinguishing agent on the metal of fire-fighting equipment at different temperatures, water film foam extinguishing agent (AFFF), synthetic foam extinguishing agent (S) and fluoroprotein foam extinguishing agent (FP), which are commonly used in fire-fighting, and two kinds of metal materials of fire-fighting equipment (galvanized steel, aluminum alloy) were selected. The immersion weight loss and electrochemical test experiments were carried out at 40～80 °C, and the corrosion rate was calculated. The key parameters such as corrosion current density were measured. The results show that the corrosion rate of the metal increases with the increase of temperature. The corrosion rates of the three foam extinguishing agents on the two metals are: FP>S>AFFF, and the corrosion resistance of the two metals is: aluminum alloy>galvanized steel. With the increase of temperature, the corrosion degree of the two metals increased. Corrosion products and pitting pits appeared on the surface of galvanized steel, and the surface color of aluminum alloy became darker. In FP, pitting pits appeared on the surface of both metals, and their number and depth increased with the increase of temperature. Based on electrochemical tests, it was found that at the initial stage of corrosion, with the increase of temperature, the corrosion current density increased, the capacitance arc diameter and charge transfer resistance decreased, and the corrosion accelerated. In addition, at different temperatures, the corrosion mechanism of aluminum alloy in three foam solutions and galvanized steel in AFFF and FP is under charge transfer control, but galvanized steel in S shows typical diffusion control.

Key words: foam extinguishing agent, fire-fighting equipment, corrosion research, electrochemistry