Influence of treatment temperature on microstructure and properties of Nickel-Zirconia anode materials for fuel cells

Abstract

Cyclic treatment technique (redox cycling) comprising stages of material exposition in reducing and oxidizing high temperature environments and intermediate degassing between these stages has been developed to improve the structural integrity of YSZ-NiO ceramic anode substrates for solid oxide fuel cells. Series of specimens were singly reduced in hydrogenous environment (the Ar-5 vol.%H2 mixture or hydrogen of 99.99 vol.%H2 purity) under the pressure of 0.15 MPa or subjected to redox cycling at 600 or 800°C. The influence of redox cycling at the treatment temperatures of 600 and 800°C on the structure, strength and electrical conductivity of the material has been analyzed. Using the treatment temperature 600°C the structure providing improved physical and mechanical properties of the material was formed. However, at the treatment temperature 800°C the anode structure with the array of microcracks was formed that reduced significantly the strength and electrical conductivity of the material.