Behaviour of Solid Oxide Fuel Cell Materials in Technological Environments

The YSZ–NiO ceramics for SOFC anodes and MAX-phases of Ti-Al-C systems for interconnects have been investigated. Based on the tests of YSZ–NiO specimens preconditioned by one-time reduction or by redox cycling at 600 or 800 °C, a certain mode of the material treatment was established which provides its improved physicomechanical properties. The oxidation behaviour of MAX-phases has been investigated at 600 °C in air. It was found that the intense initial oxidation of hot-pressed Ti3AlC2-based material can be eliminated by a certain mode of pre-oxidation. The oxidation resistance of the material can be significantly improved by niobium addition

Development of oxidation-resistant and electrically conductive coating of Ti–Al–C system for the lightweight interconnects of solid oxide fuel cells

The paper studies oxidation resistance and electrical conductivity of dense coatings produced by vacuum-arc deposition technique on α-titanium thin (0.1 mm) substrate using a hot pressed Ti2AlC–TiC target. The coatings were deposited at low (7 mA/cm2) and high (15 mA/cm2) current densities on the substrate and marked LCD and HCD, respectively. This provided different local chemical and phase compositions of the coatings. It was found that phase compositions of the coatings differ from that of the target. The HCD coating has high oxidation resistance evaluated in terms of the specific weight gain (Δm/S = 0.06 mg/cm2) as well as high surface electrical conductivity (σ = 1.23·106 S/m) after long-term (1000 h) holding at 600 °C in the air due to the formation of an over thin (450 nm) Ti–Al-(C, O, N) near-surface layer. The thin titanium substrate with such Ti–Al–C coating is recommended as a lightweight interconnect of an intermediate-temperature solid oxide fuel cell