Oxidation Behavior of TiB2 Micro- and Nanoparticles

The oxidation of TiB2 particles (75 to 1500 nm in size) has been studied at temperatures of up to 1000 degrees 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 degrees 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 degrees C leads to the formation of the rutile phase of TiO2 and boron oxide (B2O3). Moreover, at a temperature of similar or equal to 1000 degrees 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.