Dense spinel MnCo_2O_4 film coating by aerosol deposition on ferritic steel alloy for protection of chromic evaporation and low-conductivity scale formation

摘要

Conducting ceramic layers with a spinel structure of MnCo_2O_4 and a thickness of __.3 _m were deposited on ferritic stainless steel (SS) by aerosol depo_sition (AD), for use as an oxidation-resistant coating layer on the metallic interconnects of a solid oxide fuel cell (SOFC). The microstructural changes in the interface between the MnCo_20_4 and SS were analyzed, as were the subsequent electrical conductivity changes at an SOFC operating temperature of 800 °C in air. The coated spinel layers were dense without pores or cracks, and maintained good adhesion even after oxidation at 800 °C for 1,000 h in air atmosphere. Close observation of the interface between the coated spinel oxide and SS substrate indicated the presence of - 1-_m thick, Cr-rich scale formation; how_ever no MnCrCo0_4 or MnCr_20_4 spinel phase was detected. The area specific resistance (ASR) of the MnCo_20_4-coated alloy after heat treatment at 800 °C for 1,000 h was 13.4 mΩ cm~2.