Heat treatment of extruded iron-base fibers

Abstract

1. The heat treatment of fibers produced by the chemical fiber technology from a polymer binder solution with an addition of a fine powder consists of two stages: oxidation of the fibers, resulting in the decomposition and removal of the bulk of the binder, and sintering, leading to the removal of the carbon residue of the binder and to the formation of nonporous fibers. 2. Filler-containing chemical fibers can be heat treated in motion. Maximum removal of the binder from such fibers is ensured at the following rates of fiber travel through the constant-temperature zone: not more than 14 mm/min during the oxidation stage and from 5 to 60 mm/min during sintering, giving times of residence in the zone of, respectively, not less than 15 and more than 2 min. 3. Nonporous iron fibers can be produced by preoxidizing starting fibers in air at 300°C and then sintering them in a hydrogen atmosphere at a temperature of 1300°C.