Growth mechanisms of duplex n- and p-type chromia

摘要

Chromia forming alloys, such as stainless steels, are submitted to harsh environments. Their resistance to oxidation is generally ensured by the formation of an adherent and dense chromia layer. Most of the time, the growth of a thermal oxide is limited by the diffusion of point defects, which ensures the matter transport through the oxide layer. However Cr_2O_3 has a complicated defect structure, and the identification of major point defects remains difficult. Photoelectrochemistry is an interesting technique, since it makes possible to measure the semiconducting properties of the oxide, which depend on the major point defect of the passive layer. Thanks to the photoelectrochemical and microscopic characterization, we propose to study a thermally chromia grown on pure chromium in order to determine its growth mechanisms.