Thermo-kinetics of decomposition to AlN sub-micron powders of vacuum-aluminothermic origin

DOI: 10.62564/M4-VS1225

Viktor Garbuz, Vera Sydorenchuk, Lyudmila Kuzmenko, Tatyana Silinska, Tatyana Khomko, Valery Muratov, Olga Romanenko, Larisa Romanova

Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


The synthesis of AlN/B₁₂Al=3:1 (wt.) powder took place as a result of topological exothermic vacuum reactions of Al-thermic in the "BN-Al" system according to the conditions [1]. Dark gray submicron AlN powder was extracted by selective decomposition of B₁₂Al with HNO₃:H₂O=1:10 solution. The equipment and technique for measuring the mass fraction or degree of nitrogen extraction (w N₂ or q N₂) by the method of pulse-reduction extraction with carbon by gas chromatography in a helium flow at 1000-4000 K met the requirements of regulatory documents [2].The experimental procedure and calculations were carried out accordingly [3]. Reliable experimental data under equilibrium conditions of reactions of high-temperature dissociation of AlN-micro powders without the participation of carbon and with the formation of Al₄C₃ are given in the monograph [4]. The values of the standard heat content of the reactions were ΔH⁰298K AlN→Al+0.5N₂ = 323 kJ/mol and ΔH⁰298K AlN+0.75С→0.25Al₄С₃+0.5N₂ = 277 kJ/mol, respectively.The obtained average results of measurements in the field of pulse heating at temperatures of 2500-3500K were ΔH⁰298K AlN→Al+0.5N₂ = 345 kJ/mol. That is, the dissociation reaction of submicron AlN powder, despite the strikingly different properties of interaction with alkalis and acids, does not differ from the characteristics of thermal decomposition for micro powders without the participation of carbon.

Keywords
Thermo-kinetic, AlN, sub-micron powders

Acknowledgments
Not provided

References
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