ZrO₂ Effect on Mullite Ceramic Composition Obtained in Plasma Synthesis

   The study addresses a scientific and technical challenge of developing promising mullite-containing materials for high-temperature applications under extreme energy conditions.

   Purpose: The aim of the work is to investigate the effect of the ZrO₂ addition (5 to 20 wt. %) on the phase composition and microstructure of mullite composites produced by plasma synthesis.

   Methodology/approach: X-ray microtomography and IR spectroscopy show stabilization of the tetragonal phase ZrO₂ (characteristic band ∼570 cm^–1) at the ZrO₂ content of 15–20 wt. % and 120 A current, which is accompanied by local distortions of the mullite crystal lattice due to Zr⁴⁺ introduction.

   Research findings: Parameters of arc plasma synthesis are experimentally determined for the mullite ceramic composition with the addition of zirconium dioxide. It is found that an increase in the ZrO₂ content from 5 to 20 wt. % leads to a transition from dense acicular crystals to hollow branched fiber with internal channels.

   Practical implication: The obtained results can be used to create energy-efficient refractory and thermal insulating ceramic materials.

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