Preparation method of high temperature resistant multi crystal silicon carbide fiber

Abstract

The characteristics of the invention are that the spin finish aid of the organic polymer containing one or multiple of sintering auxiliary agents is in troduced before spinning. The sintering auxiliary agent is at least one of B, Al, Y, Mg, Ti, Zr. The sintering auxiliary agent can be contained in one organic polymer or different organic polymers. The organic polymer is the polymer in silazane class and silicone carbon hydride. The method improves the spinning quality. The fiber produced can bear temperature higher than 1500 deg.C with diameter less than 10 micros, possessing good antioxidation property and mechanical property, being as the new generation of the reinforcement fiber. The method is easy to realize the continuous production.

Description

technical field

[0001] The invention relates to a preparation method of high temperature resistant polycrystalline silicon carbide fiber above 1500°C. Background technique

[0002] At present, SiC fibers are mostly prepared by melt-spinning, non-melting treatment and high-temperature firing with organosilicon polymer-polycarbosilane (PCS) as the precursor. However, since the air oxidation method is usually used to cross-link the fibers in the process of non-melting treatment, a large amount of oxygen is introduced into the fibers, and because PCS is a carbon-rich precursor, the final obtained Ceramic fiber is a carbon-rich, oxygen-rich non-stoichiometric SiC fiber. When the operating temperature exceeds 1200°C, impurity oxygen will escape in the form of gaseous CO or SiO, resulting in a large number of holes in the fiber due to weightlessness, rapid growth of crystal grains, and a sharp drop in strength. Therefore, its maximum operating temperature is only about 1000°C. I...