Heat-resistant coreless silicon carbide fibres for composite materials with ceramic and metallic matrices

Abstract

The evolution of modem technology is greatly dependent on the creation of new construction materials which have high physicomecbanical indexes (strength, modulus of elasticity, rigidity, impact strength, etc.) and withstand high temperatures in oxidizing media. Composite materials (CM) with metallic and ceramic matrices reinforced with heat-resistant fibres, primarily silicon carbide fibres, are materials which can satisfy these requirements [ 1 ]. These fibres retain high strength characteristics in an oxygen-containing medium at high temperatures (above 1000~ in comparison to carbon and boron fibres, which degrade at 500-650~ [2].There are two methods of manufacturing silicon carbide fibres. One long-established method [3] consists of precipitating silicon carbide from the gas phase on a tungsten wire or carbon fibre support. This method is used in fabrication of silicon carbide and boron fibres by Textron (USA). The fibres on the support have high strength and modulus but due to the large diameter (100-150 lain) and low elongation (0.3-0.5%), they are not suitable for textile processing, and due to their high density, the weight efficiency of aircraft decreases markedly. All of this significantly restricts the area of application of these fibres.Another method of manufacturing silicon carbide fibres is used by the Japanese company Nippon Carbon, which developed and implemented new technology for industrial manufacture ofcoreless Nicalon silicon carbide fibre [4]. The method consists of spinning the fibre from polycarbosilane (PCS) and subsequent thennochemical treatment to t'oml the inorganic structure of the coreless silicon carbide fibre.Nippon Carbon has now produced experimental samples of a new generation of fibres --Nicalon-Hi [5,6], with an oxygen content one order of magnitude smaller than in mass-produced Nicalon fibres (0.2-1.2 and 10-12%, respectively). The decrease in the oxygen content in the fibre expanded the temperature range of its use to 1300-1400~ in oxidizing medium [7].The Japanese company Ube Industries developed and manufactures a coreless silicon carbide fibre modified with titanium, the Tyranno brand [8]. hnproved samples--Tyranno Loksem --have now appeared. Witb high thermooxidative stability and physicomechanical indexes, coreless silicon carbide fibres are very satisfactorily processed into different textile structures.In Russia, scientists at the All-Russian Scientific-Research Institute of Polymer Fibres (ASRIPF) and State ScientificResearch Institute of Chemistry and Technology of Hetero-organic Compounds (SSRICTHOC) are working to create coreless silicon carbide fibres. The major novelty of this research consists of the original methods of fabricating PCS and coreless silicon carbide fibres.

Control of structure formation of polycarbosilane synthesized from polydimethylsilane by Kumada rearrangement

“…22,[38][39][40] Although many precursors are available, the most successful ones for commercial polycrystalline SiCbased fibers 41 are PCS and PMCS (M 5 Ti, Zr, Al). Most ongoing research on SiC-based fibers in Japan, 42 France, 43,44 Russia, 45 Korea, [46][47][48] and China 49 utilizes PCS as the precursor, because of its low cost and high ceramic yield.…”