Oxidation resistance of micro-laminated (ZrO2-Y2O3)/(Al2O3-Y2O3) coatings on Fe-Cr alloys

Micro-laminated (ZrO2-Y2O3)/(Al2O3-Y2O3) ceramic composite coatings were prepared on Fe-13Cr (wt.%) alloy surface using an alternate electrochemical and sintering process. FE-SEM and XPS were used to characterize the coatings. Microscopic characterization indicated that the laminated ZrO2-Al2O3 coating had a nano-structure; and the deposited zirconia and alumina layers had a composition close to the stoichiometry of ZrO2 and Al2O3. A thermogravimetric experiment was used to study the oxidation resistance of the coatings on an Fe-Cr alloy, indicating that the micro-laminated coatings are more oxidation resistant than single ZrO2-Y2O3 or Al2O3-Y2O3 coating, and the oxidation resistance is further improved with increasing number of lamination layers. The improvement of oxidation resistance can be attributed to the combination of the beneficial effects of ZrO2-Y2O3 and Al2O3-Y2O3 coatings. The multi-layer coating structure can also overcome the weakness of single coating layer.