GraphiSeal is a low viscosity liquid ceramic precursor resin which heat cures to silicon carbide (SiC) in-situ
Used to infiltrate / seal porous graphite, carbon fiber composite (CFC) & similar porous substrates (even porous ceramics).
Will lower porosity, improve oxidation resistance, wear & corrosion resistance of porous graphite based products
One or more impregnation cycles will fill internalporosity (increase density) & further result in a thin film barrier on the outer surfaces.
For additional enhanced properties GraphiSeal can be combined with particulate fillers (alumina, silicon, SiC, etc.) to modify both internal & coated surface properties. Contact us for customized blends.
Attributes of GraphiSeal:
- Low viscosity ( < 10 cps), air stable liquid
- Low odor
- Hardens at 150 to 220°C in air
- Pyrolyzes to glass-ceramic in nitrogen or non-oxydizing environment at 850°C or higher.
- Compatible with most metals, ceramic powders, and carbon/ceramic fibers.
- Solvent free (low VOC’s).
$200 per quart
$500 per gallon
$1400 per 5 gallon
Processing of Porous Graphite & CFC with GraphiSeal
1) Thin pieces of graphite can be brush /spray coated; for thick pieces soak part immersed in GraphiSeal overnight to ensure full penetration of all open porosity;
2) Vacuum impregnation (completely submerging in GraphiSeal & pulling a vacuum in a belljar) can speed the process as well as penetrate deeper thickness. Do not let the Graphiseal resin foam up when under vacuum.
3) Remove impregnated parts & wipe off excess resin with paper or cloth towel.
4) Air dry (up to 220oC) in oven to drive off volatiles.
5) High temperature cure processing (>650oC) in non-oxygen environment ( Nitrogen, vacuum, etc.) to at least 850oC but no higher than 1400oC soaking for 1 hour.
6) When cooled, remove from furnace and lightly sand any excess heat cured material on the surface using SiC sand paper, being careful not to scratch the graphite or CFC surface.
a) Steps 1 through 6 above = "PIP"= Polymer Infiltration & Pyrolysis
b) Each PIP should reduce porosity by 50%.
c) During high temp process, some outgassing will occur.
d) Repeat PIP cycle if needed for lower porosity. One or more impregnation cycles will fill internal porosity more completely.