Thermogravimetric investigation of the oxidation of the ZrB2-SiO2 composite in the temperature range 800–1300°C

The kinetics and mechanism of high-temperature oxidation of the components of the ZrB2-SiO2 system are investigated using thermogravimetric and X-ray powder diffraction analyses. It is shown that the interaction between solid components of the ZrB2-SiO2 system, atmospheric oxygen, and the glass-forming melt can be adequately described by the equations of the formal kinetics of heterogeneous processes. The previously revealed effect of encapsulation of a high-melting compound by the glass-forming melt is confirmed. This effect manifests itself in the fact that, upon introduction of a silicon-containing component, the increment of the weight of a sample decreases as a result of the oxidation and the weight losses in the form of gaseous products decrease to almost zero.