Separating Test Artifacts from Material Behavior in the Oxidation Studies of HfB2 SiC at 2000 deg C and Above (POSTPRINT)
Interim rept. 6 Apr 2010-17 Jan 2012
UES INC DAYTON OH
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Oxidation characteristics of HfB2-15 vol SiC prepared by field-assisted sintering was examined at 2000 deg. C by heating it in a zirconia-resistance furnace and by direct electrical resistance heating of the sample. Limitations of the material and the direct electrical resistance heating apparatus were explored by heating samples multiple times and to temperatures in excess of 2300C. Oxide scales that developed at 2000 deg C from both methods were similar in that they consisted of a SiO2HfO2 outer layer, a porous HfO2 layer, and a HfO2 layer depleted of SiC. But they differed in scale thicknesses, impurities present, scale morphologycomplexity. Possible test artifacts are discussed.
- Organic Chemistry