| In this paper, silane coupling agent KH570and lithium fluoride as coating agent were used to coat surface of boron power, Silane coupling agent coating use the method of direct coating, lithium fluoride use the method of deposition, then characterized them with SEM, FT-IR, TG, particle size analysis and XPS.(1) The influence of pH, reaction time and reaction temperature of silane coupling agent KH570coating boron powder were investigated. The results showed that optimum coating conditions were:the boron powder mass4.0g, KH570the mass fraction of5%, a pH value of4, the reaction time was1.5h, and the reaction temperature was45℃.(2) The influence of coating amount, a coupling agent pretreatment, the stirring speed and the concentration of the bottom liquid of Lithium fluoride coated boron powder were investigated. The results showed that the optimum coating conditions were:the boron powder mass4.0g, the coating amount was3%, a coupling agent pretreatment, the stirring speed was about700r/min; the concentration of the bottom liquid is5%.The change of ignition sensitivity of B/KNO3ignition composition (ratio for50/50) and the burning rate of B/BaCrO4(ratio for10/90) delay composition with coated and uncoated boron powder was compared. The results showed that the sensitivity of ignition composition with boron powder through the surface coating was reduced, the sensitivity of boron powder coated by coupling agent was reduced more significant than LiF coated. In the aging test, the stability of the ignition composition and delay composition increased after boron powder coated and deterioration speed reduce. The results showed that the long storage stability of pyrotechnics compositios used boron coated by coupling agent improved more significant than that by LiF. |
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