High-temperature corrosion of ceramic-ceramic composites in a waste incinerator environment

Technical Report · Fri Jan 01 04:00:00 EST 1993

OSTI ID:138724

Keiser, J R; Federer, J I; Henson, T J ^[1]; Hindman, D L ^[2]

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1. Oak Ridge National Lab., TN (United States)
2. Babcock and Wilcox Co., Lynchburg, VA (United States)

Three types of ceramic composite were exposed to flue gases of a hazardous waste incinerator to assess their corrosion behavior. One composite consisted of continuously wound filaments of Al{sub 2}0{sub 3}-23 wt % ZrO{sub 2} in an alumina matrix. This composite was tested, both uncoated and coated, with zirconia on the outer surface. The second composite type consisted of the same fiber but in a zirconia matrix The third composite consisted of an alumina matrix strengthened with silicon carbide particles. Tubes of these materials were exposed in the waste incinerator at about 900{degrees}C for times up to six months. Two principal results of exposure were revealed by optical microscopy and electron microprobe examinations: flue gas constituents either penetrated the uncoated alumina matrix of the filament-wound composite, apparently through porosity in the matrix, or deposited on the surfaces of the other composite types where reaction and bonding occurred. Neither event caused significant microstructural degradation although thereaction in the composite with a zirconia matrix suggests that degradation could be a problem under more severe conditions. Apparently, the concentration of penetrating species was too small to form a significant amount of new compounds that could cause degradation within the alumina matrix of the filament-wound composite, and the temperature was too low for the deposits on the surface of the other two types of composites to react significantly with the materials during the longest exposure of 6 months. The zirconia coating on the alumina matrix composite was not adherent enough to permit an assessment of its effect.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 138724
• Report Number(s): ORNL/TM--12212; ON: DE93012430
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
36 MATERIALS SCIENCE
ALUMINIUM OXIDES
COMBUSTION
COMPOSITE MATERIALS
CORROSION
ELECTRON MICROPROBE ANALYSIS
HAZARDOUS MATERIALS
HEAT EXCHANGERS
HEAT RECOVERY
INCINERATORS
MATERIALS TESTING
MICROSTRUCTURE
NONRADIOACTIVE WASTES
SILICON CARBIDES
TEMPERATURE RANGE 1000-4000 K
WASTE HEAT UTILIZATION
ZIRCONIUM OXIDES