Corrosion of technical ceramics by molten aluminium

The corrosion of 8 types of ceramics, i.e., 1 grade of hot isostatically pressed reaction-bonded Si3N4 (HIPRBSN), 3 grades of hot pressed Si3N4 (HPSN), and 4 grades of RBSN, and 2 types of SiC (HIPSiC and Si-impregnated SiC (SiSiC)) in molten Al (pure Al and AlZnMgCu1.5) was studied. The HIPRBSN and HPSN materials exhibited almost no corrosion under the most severe conditions (1000 Deg for 750 h). RBSN having relatively high open porosity was attacked in relatively short time. HIPSiC was considerably more attacked than HIPRBSN and HPSN, but still was fairly corrosion-resistant. SiSiC had the highest corrosion of the materials investigated. The results are explained in terms of thermodn., diffusion through the metal/ceramic interface and wetting effects. [on SciFinder (R)