Fabrication and characterization of multi-scale coated boron powders with improved combustion performance: A brief review

Boron has high mass and volume calorific values, but it is difficult to ignite and has low combustion efficiency. This literature review summarizes the strategies that are used to solve the above-mentioned problems, which include coatings of boron by using fluoride compounds, energetic composites, metal fuels, and metal oxides. Coating techniques include recrystallization, dual-solvent, phase transfer, electrospinning, etc. As one of the effective coating agents, the fluorine compounds can react with the oxide shell of boron powder. In comparison, the energetic composites can effectively improve the flame temperature of boron powder and enhance the evaporation efficiency of oxide film as a condensed product. Metals and metal oxides would react with boron powder to form metal borides with a lower ignition point, which could reduce its ignition temperature.