Study on combustion characteristics and kinetics of boron in different atmosphere

In order to investigate the combustion characteristics of boron in air, CO₂, N₂ and O₂ respectively, experiments were carried out with a high-temperature thermal balance at 50~1100°C. Effect of particle size on the ignition temperature of boron was also studied. The single-curve model of Doyle integral method was adopted to calculate the kinetic parameters of the thermal reaction of boron under different atmosphere. The results show that the weight gain rate of boron in O₂ is highest. The weight gain in CO₂ is the most and least in N₂ on the contrary. The ignition temperature of boron in air, O₂ and CO₂ is 710, 697, 770°C respectively, which leads to the conclusion that increasing oxygen concentration can notably improve the ignition of boron. The ignition temperature increases slightly with the increasing of particle size. According to the kinetic calculation, the reaction of boron in air, O₂ and CO₂ are all belong to second order reaction and the rate constant in CO₂ is the minimum. The analysis of combustion products shows that the reaction between boron and O₂ is the dominant reaction in air.