Nippon Carbon Co., Ltd.

Japan Atomic Energy Research Institute

Michio Takeda

Hiroshi Ichikawa

Junichi Sakamoto

Kiyohito Okamura

Tadao Seguchi

Noboru Kasai

Masanobu Nishii

Akinori Saeki

The present invention provides a process for producing silicon carbide fibers having a C/Si molar ratio of from 0.85 to 1.39 and excellent in heat resistance and strength at high temperatures, while conventional processes have not been able to produce the fibers having the ratio of less than 1.56. The process of the present invention comprises the steps of rendering infusible precursory fibers made from an organosilicon polymer compound to obtain infusible fibers, then primarily baking the infusible fibers in a hydrogen gas-containing atmosphere while raising the temperature thereof to obtain primarily baked fibers, and further secondarily baking the primarily baked fibers to obtain final fibers. The secondary baking is performed in the atmosphere of a mixed gas of an inert gas with hydrogen chloride gas at 1,500.degree. to 2,200.degree. C.

Process for producing silicon carbide fibers

A super heat-resistant silicon carbide fiber has an oxygen content of less than 0.1% by weight. In a process for producing the super heat-resistant silicon carbide fiber, a precursor fiber prepared by spinning a polycarbosilane having an oxygen content of less than 0.8% by weight is irradiated with a radiation in an oxygen-free atmosphere or in vacuo to make the precursor fiber infusible. The infusibilized fiber is fired in an oxygen-free atmosphere or in vacuo at a temperature of from 1000.degree. to 2200.degree. C. without exposure to an oxidizing atmosphere; or stabilized in the same atmosphere at a temperature of from 300.degree. to 600.degree. C. without exposure to an oxidizing atmosphere and fired in an oxygen-free atmosphere or in vacuo at a temperature of from 1000.degree. to 2200.degree. C.

Super heat-resistant silicon carbide fibers from poly-carbosilane

Growing community of inventors

Yamato, Japan

Michio Takeda