COMBUSTION SYNTHESIS OF ADVANCED MATERIALS .1. REACTION PARAMETERS

An explanation of combustion (self propagating high temperature) synth esis (SHS) is given together with a historical perspective of the exam ination of such exothermic reactions. The application of thermochemica l functions has been used to predict theoretically the maximum adiabat ic temperature T-ad. This, combined with a knowledge of the ignition t emperature, T-ig, and the actual combustion temperature, T-c, has been used to determine the heat loss from the SHS reaction and the amount of heat needed to raise the adjacent, cold, reactant layer to the igni tion temperature in order to maintain the self sustaining nature of th e propagating mode of the reaction. The pertinent reaction parameters that control self propagating high temperature (combustion) synthesis reactions have been examined. These include: reactant particle size an d shape; powder mixing and compaction; green density; reaction stoichi ometry; impurities; volatiles and diluents; reaction environment;mode and technique of ignition; heating rate; and the effect of these param eters on the generation of hear, exothermicity and control of the SHS reaction.