EFFECT OF NANOSIZED SILICON-CONTAINING ADDITIVES ON THE SYNTHESIS AND STRUCTURE OF MAX PHASE

This study investigates the effect of nanoscale additives of elemental silicon (nSi) and silicon dioxide (SiO₂) on the solid-state synthesis of the MAX phase Ti₃AlC₂. The synthesis was carried out using powder mixtures with a composition of 2Ti/TiC/Al containing 1 and 3 wt.% silicon-containing additives. Powder preparation included mechanical activation in a planetary ball mill for 24 hours, which enhanced the reactivity of the initial components, followed by reactive sintering at 1400°C in an argon atmosphere. X-ray diffraction and scanning electron microscopy revealed that the addition of nSi and SiO₂ has a significant effect on the phase composition, defect structure, and morphology of the synthesized materials, as well as on the kinetics of phase formation. It was shown that the addition of 1 wt.% nSi promotes the formation of a more homogeneous MAX-phase Ti₃AlC₂ structure and reduces the amount of residual TiC due to intensified diffusion processes. The introduction of SiO₂ leads to the formation of a defective and porous structure with possible involvement of oxide components, which may limit the completeness of target phase formation. The obtained results demonstrate the prospects of using silicon-containing additives for targeted control of the structure and properties of MAX-phase-based materials during low-temperature solid-state synthesis and optimization of their performance characteristics.

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