Oxidation behavior of ferritic steel alloy coated with LSM-YSZ composite ceramics by aerosol deposition

Composite ceramic thick film of lanthanum strontium manganate (LSM) and yttria-stabilized zirconia (YSZ), 2-6 mu m in thickness, were deposited on ferritic stainless steel (STS444) by aerosol deposition (AD), as an oxidation resistance coating layer in the metallic interconnector of a solid oxide fuel cell (SOFC). The YSZ volume ratio in the LSM-YSZ composite layer was adjusted from 0 to 100 vol% and the electrical resistivity was measured at 800 degrees C using a DC 4-probe method. The interface microstructure and composition of the coating layer and stainless steel after oxidation at 800 degrees C in air was examined. The coated oxide layers were highly dense without pores or cracks and maintained good adhesion, even after oxidation at 800 degrees C for 250 h at all compositions. The LSM-YSZ composite ceramics showed higher stability and electrical conductivity than the sole LSM layer at 800 degrees C, possibly due to the high microstructural stability of YSZ against grain growth at 800 degrees C. (C) 2009 Elsevier BM. All rights reserved.