Abstract: A thermocouple device (A, B) and method having first and second thermoelectric elements for producing a Seebeck voltage effect for measuring high temperatures wherein the first thermoelectric element consists of a first graphite fiber strand, (10,24) and the second thermoelectric element consists of a second graphite fiber strand (12,26). The graphite fibers of the first and second strands and have different thermoelectric characteristics by virtue of different generic precursors and processes from which fibers are derived. In a preferred embodiment, the first graphite fibers are derived from a pitch precursor process, and the second graphite fibers are derived from a PAN precursor process.

Abstract: The adhesion of pitch-based carbon fiber to organic resin is improved by treatment at room temperature with a gaseous atmosphere containing from 100 to 1000 parts per million of ozone.

Abstract: The oxidation of carbon fibers from pitch is carried out directly by winding the spun fibers on to a spinning spool or bobbin, said spool comprising an open ended, porous, non-expanding or collapsible spool. The spun carbon fibers are wound on such a spinning spool so as to leave open areas between fiber bundles. A mixture of an inert gas such as air or nitrogen containing a minor amount of oxygen is used as the oxidizing gas. Oxidation is carried out in a closed zone, e.g. an oven, for a period of time of at least 4 hours at a temperature that is initially below the glass transistion temperature of the carbon fibers and is slowly increased over the oxidation time to a maximum of about 340.degree. C. The gaseous oxidation atmosphere is continuously recycled and passed through the spool to ensure that the fibers are essentially completely oxidized.

Abstract: A spinnerette for mesophase pitch includes a spinnerette body with a plurality of mesophase pitch fiber forming channels through it. Each bore includes a capillary bore section at the outlet side of the spinnerette body, a wider diameter counter bore at the inlet side and an entrance between the wider bore and capillary bore sections with the entrance wall defining a relatively flat angle for increasing the proportion of tangential cross-section pitch fibers, as compared with radial cross-section fibers.