Intermediate for producing porous silicon carbide
AssigneeThe Carborundum Company
InventorsRamesh Divakar, Sai-Kwing Lau, Stephen Chwastiak
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Abstract
Silicon carbide sintered bodies having controlled porosity in the range of about 2 to 12 vol %. in which the pores are generally spherical and about 50 to 500 microns in diameter, are prepared from raw batches containing a polymer fugitive. Sintered bodies in the form of mechanical seal members exhibit lower power consumption at low PV and, in addition, lower wear rates at high PV in comparison to commercially available silicon carbide seal members.
Claims13
A raw batch for preparing a silicon carbide sintered body having controlled porosity in the range of about 2 to about 12 volume percent, the pores therein being substantially independent and uniformly distributed throughout the body, of essentially spherical shape, and about 50 to about 500 microns in nominal diameter, the raw batch comprising:
- a) about 75 to about 95 weight percent silicon carbide;
- b) about 0.3 to about 3 weight percent of a sintering element selected from the group consisting of boron, aluminum, and mixtures thereof,
- c) about 0.3 to about 20 weight percent of a carbon source,
- d) about 1.2 to about 5 weight percent of a binder;
- and
- e) about 0.5 to about 7 weight percent of a polymer fugitive,
- the polymer fugitive being uniformly distributed as beads throughout the raw batch so as to be substantially free of contact with adjacent beads, the beads being of essentially spherical shape and having a nominal diameter of about 50 to about 500 microns.
Dependencies are inferred from the claim text.