X-ray diffraction study of self-propagating high-temperature synthesis in the Zr–Al–C system

Resumo

The phase formation process in the Zr–Al–C system during self-propagating high-temperature synthesis (SHS) has been studied by time resolved X-ray diffraction (TRXRD). The “nonuniqueness” of SHS routes in ternary solid-phase systems depending on synthesis initiation conditions has been established. No formation of ternary compounds belonging to the class of MAX phases has been observed in the considered system. It has been shown that the reaction responsible for the propagation of the combustion wave is the synthesis of ZrC, if SHS is initiated by a high-temperature pulse, and the end product also incorporates intermetallide zirconium phases. At the same time, the sequential formation of the Zr[Al] solid solution, the ZrAlC_х phase, and the intermetallide ZrAl₃, ZrAl₂, and Zr₂Al₃ phases occurs in the bulk ignition of the 2Zr–Al–C mixture under the conditions of great heat withdrawal during the reaction between an Al melt and Zr particles. No initiation of the Zr–C reaction takes place due to a low enthalpy of the reactions between aluminum and zirconium.