Tratamento superficial do aço inoxidável ferrítico com revestimento La0,6Sr0,4CoO3 para aplicação como interconectores em células a combustíveis do tipo ITSOFC

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

2011

RESUMO

High-temperature solid oxide fuel cells (800-1000°C) are energy power generation, directly converting the chemical energy into electricity by combining fuel and oxygen. With the reduction of SOFC operating temperature into an intermediate temperature range of 600-800 °C, it has become possible to replace conventional ceramics with metallic alloys for interconnects. Of the metallic alloys, ferritic stainless steels are considered among the most promising candidate materials, due to their electronic conductivity, appropriate coefficient of thermal expansion (CTE) with other components in fuel cell and low material cost. However, when exposed to high temperatures in certain atmospheres, stainless steel interconnect may suffer gradual increase in the electrical resistance, due to the formation of an oxide layer on their surface (Cr2O3). Moreover, there may be migration of chromium via chromia scale evaporation into cathode, which can lead to degradation in the electrochemical performance of the fuel cell. In this context, the application of a ceramic protective layer is one of the possible solutions to this problem. The purpose of this work was to obtain ceramic coating on the AISI 430 ferritic stainless steel. The films were obtained by spray pyrolysis technique from a precursor solution containing La, Sr and Co nitrates. After the heat treatment, it was possible to obtain the perovskite phase. The morphology, structural and chemistry of the films obtained were characterized by: scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). Moreover, the films were characterized according to adhesion and oxidation resistance. The results showed that the coated AISI 430 stainless steel presented an increase in oxidation resistance in comparison with uncoated substrate. However, although adherent, the films obtained showed irregular coverage.

ASSUNTO(S)

aço inoxidável revestimento cerâmico proteção contra corrosão

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