Physicochemical properties of the Crofer 22 APU steel with La0.6Sr0.4Co0.2Fe0.8O3-δ protective-conductive coatings prepared by pulsed laser deposition

Abstract

Commercial La0.6Sr0.4Co0.2Fe0.8O3-? powder was used for preparation of corresponding perovskite films on commercial Crofer 22 APU high chromium steel by pulsed laser deposition. The obtained films PLD1 and PLD2 with a thickness of 1.1 and 0.35 ?m, respectively, were dense and homogeneous, with good adhesion to the polished surface. Oxidation studies of the samples were carried out in air at 800?C for 200h. The calculated parabolic rate constant kp after isothermal oxidation for the PLD1 sample was 4.10 ? 10?14 g2cm?4s?1 and was approximately four times lower than the oxidation rate determined for the PLD2 sample. As a result of the oxidation process, in both cases, a thin oxide layer of chromia and Mn1.5Cr1.5O4 spinel was formed on the steel/film interface. In addition, small amounts of manganese-chromium spinel crystals were observed on the films? surfaces. Values of the specific electrical resistance at 800 ?C after 100 h of the experiment were 0.06 and 0.038W?cm2 for PLD1 and PLD2, respectively. The results indicate that the applied coatings meet the criteria set upon protective-conductive layers for interconnect materials, for the IT-SOFCs (intermediate-temperature solid oxide fuel cells) applications.