Abstract
Due to its high gravimetric heating value (13800cal/g), boron is often used as the basic component of air-breathing propellant fuels. The melting point and boiling point of boron are 2450K and 3931K, respectively. Once contacting with air, boron can easily transform into B2O3 with high boiling point 2316K under normal pressure on the surface of boron particle. To utilize the high heating value of boron, it is necessary to remove B2O3 layer on the boron particle. It was mentioned in some literatures that fluoride can help the removal of B2O3 layer, especially LiF which can react with B2O3 and produce products (i.e. BOF, LiBO2) with low boiling point. As a result, it would be easier to ignite boron particles to liberate its high heating value.By neutralizing precipitation method, LiF powders are prepared in the presence of boron powders. From XPS surface analysis, we can realize how the elements in B/LiF powders bonding with each other. SEM, TGA, DSC are also used to realize the differences in weight, structure and morphology between amorphous boron powders and B/LiF powders.From the thermal analysis, unlike the weight gain of amorphous boron powders, LiF can cause weight loss for B/LiF powders. Because of the physical attachment between boron and LiF, the particle structure and the content of LiF become the crucial factors of weight loss efficiency. With the increase of reactant concentration under the same molar ratio B/LiF=1/0.1, LiF particles have smaller size and larger surface area to enhabce the efficiency contacting with boron particles. Therefore LiF can readily contact with B2O3 on the surface of boron to promote the reaction.