Chemically activated combustion synthesis of AlON under high nitrogen pressure

Combustion Synthesis of Magnesium-Aluminum Oxynitride MgAlON with Tunable Composition

“…This information can be used to estimate how the combustion rate and temperature will change with an increase in the proportion of the spinel in the AlON/MgAl 2 O 4 ratio during the MgAlON synthesis. The combustion temperature and combustion front propagation velocity changed linearly, but as noted in [ 22 ], the combustion temperature in this system is limited by the melting temperature of aluminum oxide.…”

“…The combustion velocity does not change linearly due to an increase in the number of magnesium perchlorate decomposition products in the combustion zone, which leads to an increase in gas pressure in the combustion front. The role of magnesium perchlorate and the mechanism of its reaction with aluminum are discussed in [ 22 ]. The initial pressure of the reacting gas can significantly impact the macrokinetic parameters.…”

“…XRD analysis also confirmed the lack of reactivity in the temperature range below ~1550 °C, revealing the presence of Al 2 O 3 peaks and no presence of Al peaks, indicating the completion of the nitridation reaction at P N2 = 5 MPa. It is worth noting that in a previous study [ 22 ], peaks of unreacted Al were detected in the combustion product of AlON due to the use of a mixture with a higher amount of Al, leading to aluminum melting and the appearance of filtration difficulties.…”

“…The figure reveals that a single-phase MgAlON powder was obtained above ~1550 • C. In contrast, combustion products obtained with different amounts of Al involved in the oxidation reaction by Mg(ClO 4 ) 2 (Figure 5b) showed a different pattern: single-phase material was obtained during combustion at temperatures above ~1700 • C. XRD analysis also confirmed the lack of reactivity in the temperature range below ~1550 • C, revealing the presence of Al 2 O 3 peaks and no presence of Al peaks, indicating the completion of the nitridation reaction at P N2 = 5 MPa. It is worth noting that in a previous study [22], peaks of unreacted Al were detected in the combustion product of AlON due to the use of a mixture with a higher amount of Al, leading to aluminum melting and the appearance of filtration difficulties.…”

“…In this work, we propose a self-propagating high-temperature synthesis method for the synthesis of MgAlON, similar to the modified method for the synthesis of aluminum oxynitride presented in [ 22 ]. This method enables the synthesis of single-phase MgAlON powders through combustion without the need for external high-temperature heating.…”