Control of the reactivity of solids by changing their mechanical properties

Abstract

The feedback between the kinetics of solid-state transformations (SST) and the generation and relaxation of mechanical stresses during SST is discussed. The kinetics of phase transformations in NH 4Cl, NH 4Br, NH 4I and NH 4SCN are limited by processes of stress relaxation. The mechanisms of stress relaxation are various: slipping of dislocations for the phase transformations in NH 4Cl and NH 4Br, diffusion or domain motion for phase transformations in NH 4SCN and fracture for phase transformations in NH 4I. Means of controlling SST kinetics by changing the mechanical properties of solid reactants and products are proposed and have been partially realized.