BRAKING DEVICE AND METHOD FOR MANUFACTURING ITS ELEMENTS Russian patent published in 2022 - IPC F16D65/02 F16D69/02 C04B35/83 

FIELD: composite materials.

SUBSTANCE: invention relates to C/C-SiC composite materials for brake elements, such as brake discs. The braking device consists of several elements with two friction working surfaces made of a composite material based on carbon fibers discrete in length and a matrix comprising the first phase located near the reinforcing fibers and obtained by pyrolysis of the precursor material in a liquid state, the second phase in the form of pyrocarbon and silicon carbide phase obtained in in the process of silicification. In it, the elements on the side of their working surfaces are made of materials with a different content of silicon carbide, or in each of the elements, the material on one of the friction working surfaces has a higher content of silicon carbide than on the other; at the same time, the carbon fibers of the composite material, discrete in length, are fragmented in thickness up to the sizes of filaments, and the silicon carbide phase with its large content is located at a limited depth of the element, starting from the friction working surface, with its content in the core of the element not exceeding 10 vol. %. The method for manufacturing the elements of the braking device includes the preparation of a press mass based on carbon fibers discrete in length and a coke-forming binder, the molding of a carbon fiber blank by pressing, its carbonization, saturation with pyrocarbon and silicification. At the same time, for the preparation of the press mass, carbon fibers fragmented in thickness, up to the size of filaments, discrete in length, combined by a mechanized method in a mat with their predominant orientation in it perpendicular to its thickness, pyrocarbon saturation is produced in a methane medium by a thermogradient method with the movement of the pyrolysis zone with a temperature in the zone of 980±20°C at a variable speed along the thickness of the workpiece element, depending on the required density of the core material, materials from its working surfaces, and at the boundary between them, variable, for example, in the range of 0.125-0.25 mm/h in the thickness of the core, in the range from 0.5 mm/h to the speed corresponding to the “slip” of the pyrolysis zone, in the thickness of materials from its working surfaces and in the range from 1.0 to 0.25 mm/h on the border between them; when forming a silicon carbide matrix, before silicification of the workpiece, coke is formed in the pores of the material by impregnation with a coke-forming binder followed by carbonation and/or nanocarbon by growing it in the pores of the material by a catalytic gas-phase method or by impregnation with a suspension of nanoscale carbon particles, and silicification is carried out by a vapor-liquid phase method with the initial mass transfer of silicon into the pores of the material by the mechanism of capillary condensation of its vapors in the temperature range of 1300-1600°C, followed by heating and exposure at 1700-1850°C.

EFFECT: increase in the comfort of braking.

2 cl, 1 tbl