The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 16, 1999
Filed:
Dec. 23, 1996
James E Sheehan, deceased, late of San Diego, CA (US);
MSNW, Inc., San Marcos, CA (US);
Abstract
An improved method for producing low-cost carbon-carbon composites based on melt-impregnation of carbonaceous fiber preforms with low-melting point sugars is provided. Sugars such as fructose, ribose and sucrose are provided as impregnants via either ambient pressure or vacuum processing. Subsequent pyrolysis in air by heating to temperatures in the 325.degree. C. to 350.degree. C. range results in almost complete decomposition of the sugars to carbon. Frothing during the sugar melt-impregnation and pyrolysis process is minimized by the use of extended periods of isothermal pyrolysis or by the use of a catalyst. A hybrid process combining sugar melt-impregnation and pyrolysis with carbonaceous resin impregnation and pyrolysis is also provided as a densification enhancement. Three sugar melt-impregnation and pyrolysis cycles followed by a furfural alcohol impregnation cycle and a final sugar melt-impregnation cycle reduce the pore volume from sixty per cent in the preform to twenty-six per cent in the densified composite.