Promoting the combustion properties of boron powder through in-situ coating

Boron powder has been considered as a prime candidate as an additive in solid fuels or propellants. Unfortunately, boron ignition and combustion is hindered by the pre-existing B2O3 surface layer which slows the oxidizer attack on the underlying boron particles. Therefore, removing the pre-existing B2O3 surface layer is critical to improve the ignition and combustion performance of boron. Herein, an in-situ coating strategy is reported to be very effective in removing the pre-existing B2O3 surface layer of boron powder and improving its combustion performance. Through the in-situ coating process in ethanol, flammable 3-aminophenol/formaldehyde resin (AF) protection layer will be formed on the surface of the boron powder, replacing the pre-existing B2O3 surface layer, and preventing the surface reoxidation of the boron powder. Comparing with the untreated boron powder, such coated boron powder exhibits higher burning rate and can be ignited at lower temperature. This in-situ coating strategy can not only contribute to the extensive utilization of boron powder in high enthalpy fuels and propellants, but also shed light on the surface modification of functional materials in different fields.