Corrosion screening tests of high-performance ceramics in supercritical water containing oxygen and hydrochloric acid

The corrosion of various ceramic materials in simulated supercritical water oxidation (SCWO) environment was measured. Supercritical water with 0.44 mol kg(-1) oxygen and 0.05 mol kg(-1) hydrochloric acid was used to simulate typical SCWO conditions after the decomposition of the organic material. The experimental temperature was 465 degrees C and the pressure 25 MPa. The experiments were performed within a reactor with an inner surface made of alumina. In this very corrosive fluid only a few Al2O3- and ZrO2-based materials did not corrode severely. Homogeneous surface attach and grain boundary diffusion were observed. HIP-BN, B4C, TiB2, Y2O3 and Y-TZP disintegrated. SiC- and Si3N4-based materials showed a large weight loss, up to above 90%. (C) 1996 Elsevier Science Limited.