GB1311537A - All carbon composite disc structures - Google Patents

Abstract

1311537 Electroplating onto a carbon fibre composite BENDIX CORP 7 Oct 1970 [8 Oct 1969 17 Nov 1969] 47656/70 Heading C7B [Also in Divisions C1 and F2] In a annular brake disc formed of carbon fibres in a carbonaceous matrix and having protrusions or indentations along one of its peripheries, the region of the disc adjacent that periphery comprises a band of continuous carbon fibres which are so located in the matrix as to follow substantially the contour of that periphery. An aircraft disc brake, Fig. 1, has rotors 13, Fig. 3, constructed as above, splined by member 14 to wheel 11, and stators 15 similarly constructed splined by members 19 to stationary axle 10. Preferably the rotors and stators have frictional elements 17, 18, respectively, in the contacting regions, such elements having a coefficient of friction different from that of the carbon composite. Preferably each disc has, in the splined region, a surface coating of a material having a melting point greater than 1400‹ F or which is a viscous film-forming liquid at 1400‹F, the material being substantially inert in oxygen and substantially impermeable to oxygen. The coating may be nickel, copper, chromium, gold, silver or alloys or inter-metallic compounds of these; or alumina, berylbia, silica, zirconia, boron carbide or other carbides, molybdenum disilicide, or borides or nitrides or mixtures of such materials; or boron or silicon. A series of coatings having progressively-increasing coefficients of expansion from that of the carbon composite from the innermost layer to the outermost maybe used, e.g. molybdenum, then alloys of molybdenum and nickel and finally nickel. The coatings may be applied by electroplating, sputtering, flame spraying or arc-plasma spraying where a non-oxidizing gas such as argon, helium or nitrogen is used to form the plasma stream. The matrix material of the disc may be a carbonaceous material as such, or a material yielding a carbonaceous residue on high temperature pyrolysis such as a phenolic resin containing dispersed particulate carbon or graphite. The fibres may be of graphite. In an example, a segment of a disc was cleaned in trichloroethylene, vacuum-brushed to remove grease and particles, and then mounted as cathode in a bath at pH4, temperature 130‹F, time 15À5 hours and current density 12 amps/sq ft to produce a nickel coating 10 mils thick. In Fig. 4, (not shown), the regions not in the vicinity of the splines include randomly-oriented short carbon-fibre staple in the composite.