igniting the compacted reactants through various means), being highly exothermic it releases sufficient heat to go to completion in a very short time (of the order of few tenths of seconds), reaching temperatures as high as 2000-3000°C and beyond. SHS processes are approximated to be adiabatic and the temperature reached in the reaction front (adiabatic temperature) can be calculated from thermochemical data where available. The physico-chemical studies of SHS currently include studies of mechanism of combustion wave propagation; mathematical simulation of combustion; establishment of relationship between the product composition and operational conditions (combustion); experiments under microgravity conditions. Considerable interest has been focused in the last two decades on plasma-assisted preparation of a number of inorganic solids in the form of fine, pure powders or films for application in many areas of advanced technology. In many cases, thermal plasma processes have been substituted for conventional synthesis techniques used for ceramic powders (nitrides, borides, carbides, oxides) with good production rates and for coatings, for example of metals with harder ceramic materials. Thermal plasma reactors are characterized by the presence of highly reactive species (ions and excited atoms) not available under conventional processing conditions; thermal plasma properties usually lead to complete vaporization with associated gas-phase chemistry; moreover, rapid quenching of the products can provide new and amorphous phases. A few selected examples of SHS preparation of ceramic and intermetallic materials may be illustrated; calculation of the so-called adiabatic temperature through use of thermodynamic data may be shown.
Books A.A. Borisov, L. De Luca and A.G. Merzhanov, eds.,
“Self-propagating high temperature
synthesis”, Taylor&Francis, New York 2002, a collection of papers on the subject C.N.R. Rao, Editor, “Chemistry of advanced materials”, A ‘Chemistry for the 21st
monograph, International Union of Pure and Applied Chemistry, Blackwell Scientific Publications, Oxford,tec., 1993, 388 pp. Z.A. Munir, J.B. Holt, editors, "Combustion and Plasma Synthesis of High-Temperature Materials",
VCH, New York/Weinheim/Basel/Cambridge, 1990, pp.501. A contributed volume dealing with