Thermodynamic calculation and an experimental study of the combustion synthesis of (Mo sub(1-x)Nb sub(x))Si sub(2) (0 [< or =, slant] x [< or =, slant] 1)

• Published in: Journal of alloys and compounds 2015-08, Vol.641, p.181-187
• Main Authors: Wang, Xiaohong, Lu, Qiong, Wu, Guangzhi, Shi, Jialing, Sun, Zhi
• Format: Article
• Language: English
• Subjects: Adiabatic flow; Alloys; Combustion products; Combustion synthesis; Combustion temperature; Mathematical analysis; Niobium; Solid solutions
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2015.04.071

The theoretical adiabatic temperature of (Mo sub(1-x)Nb sub(x))Si sub(2) (0 [< or =, slant] x [< or =, slant] 1) is calculated. The results indicate that the theoretical adiabatic temperature of (Mo sub(1-x)Nb sub( x))Si sub(2) increases with an increasing Nb content when (Mo sub(1-x)Nb sub(x))Si sub(2) is of a single-phase structure, but decreases with an increasing Nb content when (Mo sub(1-x)Nb sub( x))Si sub(2) is of a double-phase structure. All of the temperatures are higher than 1800 K, indicating that (Mo sub(1-x)Nb sub(x))Si sub(2) (0 [< or =, slant] x [< or =, slant] 1) can be prepared by the combustion synthesis method. In this work, (MO sub(1-x)Nb sub(x))Si sub(2) (0 [< or =, slant] x [< or =, slant] 1) alloys are successfully synthesized by the combustion synthesis process from elemental powders of Mo, Nb, and Si. The highest combustion temperature and combustion product structure are studied. The results confirm that the variation of the experimental maximum combustion temperature of (Mo sub(1-x)Nb sub(x))Si sub(2) is consistent with that of the theoretical adiabatic temperature. The combustion products are non-equilibrium species, and a supersaturated solid solution of C11 sub(b) type (Mo sub(1-x)Nb sub(x))Si sub(2) forms during combustion synthesis.