Influence of Thermodynamics and Diffusion on Reaction Mechanisms during Gas/solid Reactions

The direct link between microstructure and material properties is the core principle underpinning modern material science and engineering. Phase transformations in solids and solidification of melts have been extensively studied to the point where the key elementary processes, process steps and process variables are well understood. Less well investigated and less well understood are the changes taking place during gas/solid reactions. Most studies have focussed determining the rates of overall reactions rather than the structures of the solid products and the reaction mechanisms at the gas/solid interface. Recent research has shown that the reaction mechanisms in these fluid/solid systems and the solid microstructures formed have direct analogies to those observed in solidification and solid/solid transformation systems. Establishing the fundamental conceptual link between these different classes of systems opens the opportunity to utilise these established theoretical frameworks to improve existing process technologies and to develop and manufacture new material structures.