Boron is an attractive fuel for propellants and explosives because of its high energy density . However, boron particles are difficult to combust because of inhibiting oxide layers that cover the particles. The use of magnesium as additives has been shown to promote boron oxidation . In this study, laser ignition facility and thermobalance were used to investigate the effect of magnesium on the burning characteristics of boron particles. The influences of magnesium addition on sample combustion flame , boron ignition delay time, boron combustion efficiency and initial temperature of boron oxidation. Results show that all Mg/B samples exhibit the same type of flame structure, i.e., a bright plume surrounded by green radiation which is interpreted as BO 2 emission. The combustion flame intensity of a sample increases with the increasing magnesium content of boron particles. An increase in magnesium content results in a decrease and a subsequent increase in boron ignition delay time. (Mg/B) 0.2 has a minimum ignition delay time of ~48 ms. Boron combustion efficiency increases with increasing magnesium addition. (Mg/B) 0.5 shows a maximum boron combustion efficiency of ~64.2%. Magnesium addition decreases the initial temperature of boron oxidation.
The existence of an oxide (B 2 O 3 ) film covering the boron (B) surface affects its energy release during combustion. Fluoropolymer modification can help to solve the problem. The electrospinning and solvent anti-solvent methods were utilized to modify boron nanoparticles (n-B) using polyvinylidene fluoride (PVDF) as a modified material, which can effectively coat B particles. The thermal behavior, combustion characteristics, and condensed combustion products of the B/PVDF composites were investigated and evaluated. The agglomeration size of B particles can be decreased while its reaction heat and combustion intensity are increased. Significantly, the combustion performance of the B/PVDF composites prepared by the electrospinning method is better than that of the B/PVDF composite prepared by the solvent anti-solvent method. These results can be helpful in promoting the practical application of B.
A composite ceramic coating containing h-BN particles was prepared on the ZL109 alloy via plasma electrolytic oxidation. The h-BN particles were modified by Polyethylene glycol to improve the dispersibility. The results revealed that the h-BN particles in the electrolyte were inertly incorporated into the coating. Meanwhile, the incorporation of h-BN particles can reduce the porosity and slightly increase the roughness of the composite ceramic coating. Furthermore, the growth rate of the coating and the conversion of γ-Al 2 O 3 and α-Al 2 O 3 were promoted by the incorporation of h-BN particles via the change of the current. In addition, due to the presence of h-BN particles, the composite ceramic coating had a lower friction coefficient and a lower wear rate under dry sliding condition.
危险品化学品经营许可证（带存储）