Process for making high strength flexible graphite foil
AssigneeStackpole Carbon Company
InventorJohn W. Borkowski
Life of this patent
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Abstract
Finely-divided graphite flake is heated to a high temperature in the presence of boron or a boron-containing compound to cause the boron to permeate the crystal structure of the flake, which is then subjected to an intercalating agent and rapidly heated, resulting in an expanded or vermicular graphite with a bulk density substantially less than what might be expected if the flake were not pretreated with boron. The expanded graphite then is compressed to form a preform that is reduced in thickness by rolling or molding to form a higher-strength flexible graphite foil than heretofore.
Claims11
A process for making a high strength flexible graphite foil, comprising heating finely divided graphite flake in the presence of boron to a temperature between about 1700.degree. C and 3000.degree. C until the boron has substantially completely permeated the crystal structure of the graphite flake, then subjecting the graphite flake to an intercalating agent and rapidly heating to a temperature between 300.degree. C and 1100.degree. C to expand the flake until it has a bulk density substantially lower than expanded flake not pretreated with boron, compressing the expanded graphite to make a preform, and further compressing the preform to form a flexible graphite foil.
Dependencies are inferred from the claim text.