A new approach to the study of solid-state reactions in oxide ceramics

Abstract

Thin-film reactions have potential applications for the production of buffer layers in heterojunctions and for the reaction bonding of materials. The main drawback to these applications at present isthat the effect of interface morphology on the initial kinetics of solid-state reactions is not well understood. In order to study the kinetics and mechanisms of thin-film reactions in oxide ceramics, a new method has been developed. The approach relies on the production of a well characterized high-quality oxide thin film on a single-crystal oxide substrate which makes up the idealized reaction couple-a ‘single-crystal’ thin film in intimate contact with a single crystal substrate. The thin-film approach localizes the reaction near the surface of the specimen so that conventional cross-sectioning techniques can be utilized. Additionally, the scale of the reaction is of the order of tens of nanometers or less which is ideally suited to high-resolution SEM or conventional TEM.NiO/α-Al2O3 is a model system for the study of solid-state reactions.