SURFACE TREATMENTS FOR FIBROUS CARBON REINFORCEMENTS.
Abstract
Studies have been conducted to improve the performance of structural and ablative composites composed of graphite- and carbon-fiber reinforced epoxy and tested for changes in interlaminar shear strength. Carbon fibers were coated with nickel and several oxides, and the oxidation resistance measured by thermogravimetric analyses in air. Chemical oxidation by nitric acid and thermal oxidation in air of graphite fibers were performed and found to increase the interlaminar shear strength of graphite/epoxy composites. These treatments also increased the surface activity of the fibers as measured by chemical group analysis and surface area. The surface cleaning treatments of solvent extraction and degassing were less effective in increasing composite shear strength, as were several chemical finishes applied to graphite and carbon fibers. The nickel coating of fibers had little effect on composite shear strength; a nylon coating produced a moderate increase. Of several oxides deposited on carbon fibers, the application of silica by vapor-phase deposition yielded the best coating and resulted in a moderate increase in oxidation resistance of the fibers. Deposition by electrophoresis and from organosilicates were attempted, but uniform fiber coatings were not obtained. Nickel, platinum, and rhodium were coated on carbon fibers electrochemically, with electroless nickel producing the best coatings. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1966
- Accession Number
- AD0489187
Entities
People
- Frank T. Mansur
- John W. Herrick
- Philip E. Gruber Jr.