GraphiSeal is a low viscosity liquid ceramic precursor resin which heat cures to silicon carbide (SiC)
Used to infiltrate / seal porous graphite, carbon fiber composite (CFC) & similar porous substrates
Will improved oxidation, 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 surface
For additional enhanced properties GraphiSeal can be combined with particulate fillers (alumina, silicon, SiC, etc.) to modify both internal & coated surface properties.
Attributes of GraphiSeal:
- Low viscosity ( < 10 cps), air stable liquid
- Low odor
- Hard cures at150 to 220°C in air
- Pyrolyzes to glass-ceramic in nitrogen or non oxygen environment at 850°C
- Compatible with most metals, ceramic powders, and carbon/ceramic fibers
- Solvent free (low VOC’s)
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 cure (up to 220oC) in oven
-High temperature processing( >600oC ) in non-oxygen environment ( Nitrogen, vacuum, etc) to at least 850oC but no higher than 1400oC soaking for 1 hour.
5) Repeat cycle if needed. One or more impregnation cycles will fill internal porosity more completely.
6) Note that during high temp process, some outgassing will occur.
7) Lightly sand any excess heat cured material on the surface using SiC sand paper carefully.