Combustion performance of aluminum modified boron nanoparticles coated with silane coupling agent

Abstract

Boron (B) powder, with its high mass and volumetric heat values, makes it highly promising in the field of energetic materials. However, the oxide layer on the B surface is the most significant barrier to realizing its full potential as a fuel. How to eliminate or disrupt the oxide layer is currently an urgent problem that needs to be addressed. This study proposes an approach to enhance the combustion of nano-B powder by coating aluminum (Al) onto its surface using a silane coupling agent. The combustion characteristics of Al-modified B powder with different Al contents were investigated through experimental and molecular dynamic simulation methods, and the bidirectional diffusion mechanism on the interfacial layer of modified B particles was revealed. A small amount of Al powder can largely lower the initial oxidation temperature of B powder, increase the maximum flame temperature, and enhance the heat release. However, an excessive amount of Al powder leads to a deterioration in the combustion of B powder but can alter the combustion behavior and suppress the aggregation of B powder during the combustion. Additionally, combination reaction and redox reaction occurring during the combustion of B@Al samples not only reduce the burning time of B powder but also accelerate the flame expansion speed and improve the combustion efficiency. These results lay the foundation for the application of B@Al in the field of energetic materials.