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Title: Materials support for HITAF. Final report for Phase 1

Technical Report ·
DOI:https://doi.org/10.2172/93420· OSTI ID:93420

Improvements in coal-fired systems will require a change from steam turbines to gas turbines using air as working fluid; pressurized ceramic heat exchangers operating up to 1600 C will be needed. Leading candidate materials are SiC-based ceramics. Mechanical properties of 3 materials are compared in this work: NT230 Si/SiC from Saint Gobain Norton, {beta}-SiC from Coors Ceramics Co., and Lanxide DIMOX SiCp/Al{sub 2}O{sub 3} from Du Pont Lanxide Composites Inc. The first material is siliconized Si carbide, the second is sintered. They all were tested in 4-point flexure at RT and 1100 and 1400 C. Fast-fracture tests were carried out. Slow crack growth was investigated. Failure modes were studied using optical microscopy and SEM. Four materials were exposed to two coal ashes at two different temperatures. In the comparison, Coors {beta}-SiC stands out from a strength and reliability standpoint when exposed to air at high temperatures. Lanxide DIMOX withstood coal ash exposure well.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC05-84OR21400
OSTI ID:
93420
Report Number(s):
ORNL/TM-12815; ON: DE95015799
Resource Relation:
Other Information: PBD: Mar 1995
Country of Publication:
United States
Language:
English