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Silicon, boron, and zirconium boride coatings on graphite have been obtained by thermal treat ment of the initial components in air. During the course of the chemical reactions, a glass melt encapsulating (wrapping) the initial particles is formed, which makes it possible to create an air barrier preventing the dif fusion of oxygen into the sample. The interactions between the components of the Si-B-ZrB 2 system with oxygen and the glass forming melt have been investigated.

The kinetics and mechanism of high-temperature oxidation of the components of the ZrB 2 -SiO 2 system are investigated using thermogravimetric and X-ray powder diffraction analyses. It is shown that the interaction between solid components of the ZrB 2 -SiO 2 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.

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