Corrosion Behaviour of SiC Laminate under Decomposed Sulphuric Acid at 850°C

In view of the possible application of SiC-based ceramic laminates as critical components of hydrogen generation plants based on sulphur-iodine or hybrid-sulphur thermo-chemical cycles, the effect of corrosion on this kind of ceramics has been investigated. For this purpose the material was exposed for 1000 h at 850°C to the corrosive action of a gaseous atmosphere simulating the environment of a sulphur-based thermo-chemical hydrogen generation plant (a gaseous mixture containing several aggressive species: O2, H2O, SO2, SO3 and H2SO4, with relative concentrations representative of the inlet of an SO3 decomposer reactor). Specimens of multilayer SiC were prepared according to the following processing path: tape casting of a SiC-based slurry, building of the green multilayer by stacking eleven sheets, final de-binding and sintering treatments. The material microstructure and its flexural strength and modulus were studied before and after corrosion to investigate degradation phenomena. The microstructure was investigated by XRD, SEM-EDS, XPS and density measurements. Flexural strength and modulus were measured by fourpoint bending test. The corrosive atmosphere displayed an oxidizing effect that resulted in the formation of silica, oxycarbides and gaseous products of carbon oxidation. Nevertheless the corrosion was hindered by the formation on the sample surface of a passivating silica layer. Bending strength and modulus were found unchanged or even improved after corrosion.

BADINI Claudio;  DE HAAN Fredericus;  CELASCO Edvige;  HAEHNER Peter;  VEGA BOLIVAR Claudia;  BIAMINO Sara;  PAVESE Matteo;  FINO Paolo; 

2012-10-16

WILEY-BLACKWELL

JRC72002

0002-7820,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC72002,   

10.1111/j.1551-2916.2012.05337.x,