A New Experimental Apparatus for In-Situ Characterization of Silica Growth During Passive Corrosion of SiC at Very High Temperatures

摘要

A new experimental method based on Joule-heating and interferometry was developed in order to gather in situ quantitative information on the kinetics of silica growth during passive corrosion of SiC under CO_2-containing environments at very high temperatures. This method proved efficient in studying the thin-oxide regime and the initial linear regime as well as the parabolic regime described in the Deal-Grove rate law. Linear rate constants followed an Arrhenius law with a very high activation energy of 593 kJ mol~(-1) and were independent of gas composition, suggesting the chemical reaction at the SiC/SiO_2 interface involved a vacancy mechanism.