Bonded bulk graphite and process for bonding
AssigneeThe United States of America as represented by the Secretary of the Army
InventorsDennis M. Riggs, Edward L. Harvey
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Abstract
Bulk pieces of graphite bonded with a graphitizable binder comprising a lid crystalline component of pitch, which softens at about 240.degree. C. and becomes very fluid at about 300.degree. C. to about 500.degree. C. The bonded graphite pieces appear as a monolithic material even under 1000.times. magnification. The bonding is effected under vacuum or in an inert atmosphere at temperatures of from about 700.degree. C. to about 3000.degree. C., usually about 1000.degree. C. to about 1500.degree. C., under pressure of from about 20 psi to about 1000 psi applied in a direction normal to the bonding surface.
Claims5
A process for bonding graphite pieces together wherein a graphitizable binder consisting essentially of a liquid crystalline component of pitch obtained by extracting an isotropic pitch with a hydrocarbon solvent to yield a solvent insoluble fraction which softens at about 240.degree. C. and becomes very fluid at about 300.degree. C. to about 500.degree. C. is spread uniformly over at least one of the two graphite surfaces to be bonded together, the pieces are then joined and held in intimate contact and the entire assemblage is heated under vacuum or in an inert atmosphere to a temperature in the range of from about 700.degree. C. to about 3000.degree. C. under a pressure of from about 20 psi to about 1000 psi applied in a direction normal to the bond interface until bonding is effected.
Dependencies are inferred from the claim text.