M. De Stefano Fumo, R. Gardi, M. Tului, F. Arcobello Varlese, S. Lionetti, M. Fortunato
DOI Number XXX-YYY-ZZZ
Conference Number HiSST-2022-0282
Ceramic coatings are widely used as thermal barrier or as oxidation barrier, in many industrial applications. The use of UHTC is mandatory when dealing with hypersonic vehicles characterized by high thermal flux in oxidizing environment. Ultra-high temperature ceramics (UHTCs) such as ZrB2 and HfB2 have been identified as potential candidates for operating in harsh conditions and their resistance to ablation. However, their poor fracture toughness and thermal shock resistance strongly limit their applicability. On the contrary, metallic refractory alloys have good thermo-mechanical properties but suffer from poor oxidation resistance.The combination of metallic substrates with plasma spray coating of UHTC can potentially couple the high oxidation resistance of UHTCs to the better thermo-mechanical properties of substrates. CIRA and RINA-CSM is developing and improving the features and the capabilities of the UHTC coating by plasma spray on metallic substrates. A wide campaign for characterization and selection of ceramic coatings, substrates and spraying techniques were performed. Arc-jet test campaigns on small samples are carried out in the 2MW facility GHIBLI. Large scale metallic cone coated with UHTC have been tested in the 70MW SCIROCCO facility, to characterize the behavior of the proposed materials combinations under representative conditions using also representative geometries and size. The paper shows all the preparatory activities and the results obtained in PWT tests on UHTC coating.