Interfacial oxidation of boron proceeds through a stable B₆O intermediate
Jian Wang, Kai Zhong, Kai Zhong, Yaofeng Mao, Jie Chen, Fude Nie, Huiyang Gou, Huiyang Gou, Jun Wang, Jun Wang
Abstract
The oxidation of boron (B) is of great significance in catalysis, metallurgy, corrosion, and combustion. However, understanding the early stages of oxidation and identifying intermediate phases remain a long-standing challenge. Here we reveal an oxidation mechanism termed the W–J model; unlike classical models that rely on the diffusion of oxygen or boron through a B2O3 layer, the initial reaction in the W–J model takes place at the interface between the boron core and the B2O3 shell. This interfacial reaction produces an oxidized intermediate, B6O, which is then further oxidized to form B2O3. The formation of B6O plays a crucial role in regulating the oxidation process. Its high thermal stability and strong oxygen affinity act as barriers to continuous oxidation, thereby lowering the ignition and combustion efficiency of boron. These findings highlight a fundamentally different reaction pathway that may help explain the limited reactivity observed in practical applications. Researchers uncovered a boron oxidation pathway, the W–J model, where B6O forms at the B/B2O3 interface. Acting as a stable barrier, B6O slows further oxidation, offering insight into boron combustion and efficiency optimization.