Comparison of results of 200- and 500-h exposures of silicon carbide to a slagging coal gasification environment

Technical Report · Tue Apr 01 04:00:00 EST 1986

OSTI ID:5787034

Easler, T E

The corrosion behavior of silicon carbide was studied in laboratory tests to determine whether the material has potential for use in the hot, dirty gas stream issuing from a slagging coal gasification vessel. In this report, the results of 500-h exposure tests of a siliconized silicon carbide material are compared to earlier reported results of 200-h tests in the same environment. It was found that specimens exposed to typical effluent gas compositions in the absence of slag formed surface oxide scales, the growth rate of which increased slightly with time, possibly as a result of accelerated oxidation in the presence of the high steam partial pressure. Acidic-slag-coated samples exhibited an increase in corrosion rate with exposure time, while the corrosion rate for basic-slag-coated samples remained nearly constant. Corrosion products included an iron-rich phase, possibly Fe/sub 2/Si, which penetrates specimens along grain boundaries, where it interacts with the free silicon in the material. A silica-rich layer, which does not seem to greatly inhibit reactant and product diffusion, was also observed at the slag/silicon carbide interface. Strength degradation was most notable for the basic-slag-coated samples; the measured strengths were less after the longer-term 500-h exposure period than were observed after the 200-h tests. The test results indicate a rather limited life expectancy for silicon carbide in the hot, dirty gas stream. 12 refs., 6 figs., 4 tabs.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5787034
• Report Number(s): ANL/FE-85-13; ON: DE86010625
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404* -- Coal
Lignite
& Peat-- Gasification
36 MATERIALS SCIENCE
360205 -- Ceramics
Cermets
& Refractories-- Corrosion & Erosion
BENCH-SCALE EXPERIMENTS
CARBIDES
CARBON COMPOUNDS
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
COAL GASIFICATION PLANTS
CORROSION
CORROSIVE EFFECTS
CRYSTAL STRUCTURE
DATA
ELECTRON MICROSCOPY
EXPERIMENTAL DATA
GRAIN BOUNDARIES
INDUSTRIAL PLANTS
INFORMATION
MATERIALS TESTING
MICROSCOPY
MICROSTRUCTURE
NUMERICAL DATA
OPTICAL MICROSCOPY
SCANNING ELECTRON MICROSCOPY
SILICON CARBIDES
SILICON COMPOUNDS
SIMULATION
SLAGS
TESTING
TIME DEPENDENCE
VERY HIGH TEMPERATURE