The exceptional chemical stability and thermomechanical properties of zirconia drives its versatility across a wide range of applications. In aggressive environments exposed to constant steam and coolant water such as in nuclear reactor systems, the hydrogen uptake and corrosion behavior of zirconia is a critical subject. In the recent years, a broader interest on this topic is stimulated by the sustainability-driven shift from a carbon- to a hydrogen-based energy system. Thermodynamic calculations suggest the superior resistance of zirconia against hydrogen attack at elevated temperatures when compared to other common refractory phases. However, this performance is yet to be validated in real systems where kinetics and the complex composition of refractory ceramics like bricks and monolithics are crucial factors. 

This study explores the corrosion resistance of stabilized zirconia under pure hydrogen atmosphere. Zirconia stabilized with yttria, resp. calcia were pressed into cylindric shapes. The tests were performed both at 950°C and 1400°C for a total duration of 240 h. During the same thermal treatment, pure phases of common refractory raw materials were simultaneously loaded to test for possible cross-reactions. Through microstructural analysis, the results highlighted the influence of the type of stabilizer to the corrosion resistance of zirconia. Calcium was found to have a catalytic role in promoting cross reactions with the siliceous by-product gas triggering the destabilization of zirconia. The goal is to valorize the observed mechanism of corrosion in the conception of innovative refractory solutions for sustainable hydrogen-based processes.