Analysis of Candidate Silicon Carbide Recuperator Materials Exposed to Industrial Furnace Environments

摘要

Several SiC ceramics were exposed to the combustion environment in six industrial furnaces to determine their corrosion resistance. The matrials were sintered- alpha (Hexoloy SA), Sintride, recrystallized (NC-400), CVD SiC coated NC-400, siliconized (NC-430), reaction sintered (SC-X and KT), and Si sub 3 N sub 4 -bounded (C/75 and CN-178). Tubes of these materials were exposed in two aluminum remelt furnaces, a forge furnace, a steel reheat furnace, and two steel soaking pits at temperatures of 925 to 1250 exp 0 C for periods of 530 to 5545 h. Significant corrosion occurred in specimens exposed to aluminum remelt furnaces and one of the steel soaking pits, whereas corrosion in the other furnaces was substantially less or negligible. The average C-ring fracture strengths of Hexoloy SA and NC-430, the only materials so tested, were substantially affected by the exposures. The lowest strength in Hexoloy SA occurred in specimens exposed in an aluminum remelt furnace, while the lowest strength in NC-430 occurred in specimens exposed in a steel soaking pit. These results show that SiC ceramics are susceptible to both corrosion and strength degradation when exposed to certain furnace environments. (ERA citation 10:048973)