High-energy brake and brake components
AssigneeFriction Products Inc.
InventorsWillie H. Watts, Francis J. Lowey, deceased, BY Old Phoenix National Bank, executor
Life of this patent
Estimating the term…
Abstract
Molded articles of carbon or graphite suitable as heat absorbing or friction elements in brakes for jet aircraft are made by coating devolatilized carbon particles with a phenolic resin, especially boronated phenolic resin, reducing the volatile content of the coated carbon to below a critical value, mixing these with a resin coated or uncoated powdered abrasive, molding under critical pressures and temperatures, and then post-curing the resin and carbonizing and optionally graphitizing the product according to a schedule whereby delamination is avoided.
Claims17
A method of making a friction element suitable for receiving the rapidly dissipated energy produced in stopping jet aeroplanes, said method comprising (a) coating a finely powdered graphite, graphite fibers, and an abrasive powder that is stable at graphitizing temperatures with a heat-setting, resole phenol-aldehyde resin, said resin being heat-setting to the infusible, insoluble state, removing volatiles therefrom while in the powdery state and at a temperature maintained below resin-curing temperatures;
- (b) preparing an intimate mixture of 1 to 10 percent by weight of said fibers, 40 to 70 percent by weight of said graphite powder, 1 to 10 percent by weight of said abrasive powder, and 20 to 45 percent by weight of said resin;
- (c) compressing said intimate mixture to form a preform at a pressure of 10 to 25 TSI but at a pressure below that which forms an impervious skin over the surface of said preform;
- (d) curing said preform to complete condensation of said resin binder while allowing vapors evolved to escape without rupturing said preform;
- (e) carbonizing said cured preform by slowly raising the temperature thereof to carbonize said resin while permitting gas or vapors formed to escape without rupture of said preform;
- and (f) graphitizing the carbonized preform by raising the temperature thereof at a controlled rate to between 1800.degree. C. and 2500.degree. C.
A process for producing molded articles which consist principally of carbon and which have relatively high strength and resistance to decomposition by frictional heat, which comprises drying a finely divided carbon powder to constant weight at about 350.degree.F., coating the powder while at a temperature of 200.degree. to 250.degree.F. with a preheated resol-type phenol-formaldehyde resin, pulverizing the dry mixture thus obtained, volatilizing the coated powder to a volatile content of less than 4 percent, molding the powder at a pressure of at least 11/2 TSI and at a temperature and pressure and for a time below that where surface porosity is reduced to the point where delamination of the molded article occurs but at a temperature where a solid compact is obtained, stripping the product from the mold at substantially the mold temperature, heating the molded article at gradually increasing temperatures over a period of more than one day to about 450.degree.F., to insure complete condensation of the resin and then carbonizing the product in an inert atmosphere at gradually increasing temperatures to 1800.degree.F., over a period of more than one day.
Dependencies are inferred from the claim text.