Authors: J.A. Puszynski, H.L. Khachatryan, K.V. Maukyan and S.L. Kharatyan
Affilation: South Dakota School of Mines and Technology, United States
Pages: 397 - 402
Keywords: combustion synthesis, nanopowders, ceramics
A combustion synthesis, also called self-propagating high-temperature synthesis, has been found to be an effective and economical production method of advanced ceramic and intermetallic compounds. This method is very suitable for the formation of nonstoichiometric compounds, solid solutions, and refractory composites. Many reacting systems, especially those involving elemental reactants, may generate a sufficient amount of energy to be self-sustaining. Addition of certain reactive additives and chemical promoters result in the significant modification of the reaction mechanism. Due to a gas transport of key reactant(s) on particle-to-particle level, products with average particle sizes at nanoscale can be obtained by using this high temperature technique. The formation of other ceramic composite powders with a very high specific surface area, such as SiC, AlN-BN, BN-B4C, and MoSi2-Si3N4, using chemically active organic and inorganic gas transport promoters will be presented in detail as a function of key processing parameters, including system pressure, reactant composition, and amount of gas transport promoters. Thermodynamics and reaction mechanisms of these reactions will be presented.<br>In-situ formation by exothermic reaction and densification of nanostructured TiAl3-Al2O3 composites from aluminum and titanium dioxide nanopowders will be discussed as well.