摘要:
The present invention is related to a method of producing polycarbosilane by heating polydimethylsilane at low pressure within the range of 320˜450° C. using zeolite having the Si/Al or Si/B ratio of 1˜200 as catalyst. This invention uses a zeolite with the structure of ZSM-5, ZSM-11, ZSM-12, zeolite X and zeolite Y, which has the Si/Al or Si/B ratio of 1˜200, as catalyst. When polycarbosilane is produced using a specific zeolite as catalyst, Si/Al or Si/B ratio can be adjusted at any proportion, enabling acidity control of catalyst, and therefore the molecular weight of final products can be easily controlled and the product yield can be improved, compared to conventional solid acid catalysts.
摘要:
The present invention relates to a clutch for transmission power. The clutch for transmission power according to the present invention includes flywheel, clutch cover and clutch disk assembly positioning between the flywheel and the clutch cover; moreover, the clutch disk assembly includes a clutch facing having main body portion formed with a center hole in the middle thereof, and a contacting portion wherein one side thereof faces the friction pad at said flywheel side and the other side thereof faces the press plate of said clutch cover, and the portion facing each other between the friction pad and the press plate is made of carbon-carbon composition; a spline hub being overlapped with one side of the clutch facing wherein a spline groove is formed in the inner diameter thereof and a connecting means for connecting the clutch facing with the spline hub. Furthermore, the clutch disk assembly and the method of manufacturing the friction substance for clutch according to the invention can improve assemblability and reduce weight by simplifying it as a single part without using shock absorbing apparatus such as coil spring or the like on clutch disk assembly. In addition, the power transmission of an engine can be improved, and also it has an effect that an automobile can start softly and slippage does not occur even at abrupt acceleration by providing with carbon-carbon composition or carbon-silicon carbide composition having excellent shock absorption function.
摘要:
The present invention relates to a method of producing carbon fiber reinforced ceramic matrix composites, the method of producing carbon fiber reinforced ceramic matrix composites according to the present invention is characterized in that the method comprises the steps of: producing a carbon fiber reinforced resin composite that is molded with a mixture in which carbon fibers and polymer precursors containing carbon are mixed; producing a carbon fiber reinforced carbon composite by depositing pyrolytic carbon during a rapid thermal gradient chemical vapor infiltration process while increasing the deposition speed in a direction from the inside to the outside by performing a thermal treatment on said carbon fiber reinforced resin composite at high temperature; and infiltrating liquid-phase silicon into the pores of said carbon fiber reinforced carbon composite. The method of producing carbon fiber reinforced ceramic matrix composites according to the present invention as described above has the effect of improving the properties of carbon fiber reinforced ceramic matrix composites, and it is possible to deposit a pyrolytic carbon layer at a deposition speed 5-10 times faster than other conventional chemical vapor infiltration processes, thereby showing a remarkably improved effect in terms of manufacturing process, time, and cost.
摘要:
A method for manufacturing carbon-carbon composites includes steps of producing a mat using carbon fiber, carbon fabric, carbon sheet, or staple fiber; laminating at least three layers of mats; producing a preform using the laminated mats with a needle punching method; performing a first thermal treatment process on the produced preform at a predetermined temperature; densifying the first-thermal-treated preform; performing a second thermal treatment process on the densified preform; forming a predetermined shape out of the second-thermal-treated preform; and performing an oxidation resistant treatment process of the shaped preform.
摘要:
A carbon--carbon composite for friction products comprises an outer friction part and a load bearing structure part supporting the friction part. The friction part contains a mixture of carbon fibers, pitch powder and graphite powder, whereas the structure part is comprised of a pack of alternating layers of the mixture and layers of one member selected from the group consisting of carbon fabrics, carbon-based prepregs and carbon-based, segmented prepregs. The carbon--carbon composite is formed by way of aternatingly piling up layers of a mixture of carbon fibers, pitch powder and graphite powder and layers of one member selected from the group consisting of carbon fabrics, carbon-based prepregs and carbon-based, segmented prepregs one above the other to provide a preform, heating and pressing the preform within a mold to obtain a green body, carbonizing the green body to prepare a carbonized body, impregnating the carbonized body with pitch powder and recarbonizing the impregnated body, and subjecting the impregnated and recarbonized body to chemical vapor infiltration with hydrocarbon gas.
摘要:
The present invention relates to a method of more precisely and easily realizing cooling channels constituting a ceramic brake disk rotor. In order to achieve an object of the invention, there is provided a method of manufacturing a ceramic brake disk rotor having internal cooling channels, comprising the steps of: (a) producing loading portions 110, 210, frictional surfaces 120, 220, and vanes 300 of the disk rotor respectively through separate processes using a carbon fiber reinforced carbon-carbon composite; (b) fabricating the loading portions 110, 210, frictional surfaces 120, 220, and vanes 300 respectively produced through separate processes into one structure and (c) performing a liquid silicon-melt infiltration process for the fabricated one structure. According to the present invention, a shape of the cooling channel can be economically and easily realized, and furthermore the dimensional precision of the cooling channel is enhanced, thereby having an effect of improving the performance of the disk rotor.