X-ray computed tomography study of microstructure weakening by high-temperature hydrogen attack on refractories

Abstract

X-ray computed tomography (XRT) is a three-dimensional (3D), non-destructive, and reproducible investigation method capable of visualizing and examining internal and external structures of components independent of the material and geometry. In this work, XRT with its unique abilities complements conventionally utilized examination methods for the investigation of microstructure weakening induced by hydrogen corrosion and furthermore provides a new approach to corrosion research. The motivation for this is the current inevitable transformation to hydrogen-based steel production. Refractories of the system Al₂O₃-SiO₂ are significant as lining materials. Two exemplary material types A and B, which differ mainly in their Al₂O₃:SiO₂ ratio, are examined here using XRT. Identical samples of the two materials are measured, analyzed, and then compared before and after the hydrogen attack. In this context, hydrogen corrosion-induced porosity and its spatial distribution and morphology are investigated. The results show that sample B has a higher resistance to hydrogen-induced attack than sample A. Furthermore, the 3D representation revealed a differential porosity increase within the microstructure.