Oxidation behavior of TiB2 micro- and nanoparticles

Resumo

The oxidation of TiB₂ particles (75 to 1500 nm in size) has been studied at temperatures of up to 1000°C by thermogravimetry, X-ray diffraction, X-ray photoelectron spectroscopy, IR frustrated total internal reflection spectroscopy, and energy dispersive X-ray analysis. The oxidation onset was observed between 210 and 475°C, depending on the particle size. This distinction can presumably be accounted for in terms of the deformation produced by the Laplace pressure. Oxidation at temperatures under 1000°C leads to the formation of the rutile phase of TiO₂ and boron oxide (B₂O₃). Moreover, at a temperature of ≃ 1000°C titanium borate, TiBO₃, was observed to form. Under all of the conditions examined, the oxidation reaction does not reach completion and the oxidation products contain unreacted TiB₂.