GB645126A - Antifriction elements of the graphitic type for bushes, packings, joints, washers and the like and method for manufacturing same - Google Patents

Abstract

Antifriction parts such as brushes, packings, joints, and washers are manufactured by forming a compact agglomerate of carbonaceous material, stoving to convert the agglomerate entirely into artificial graphite, impregnating the graphite with a substance which, by polymerization or condensation, is capable of hardening, and treating the impregnated agglomerate to effect partial hardening of the impregnant which is left in a semi-plastic state. Suitable impregnants are natural or artificial resins, oils, chlorinated aromatic compounds, or cellulose products. The parts of lamp black, sugar charcoal, petroleum pitch or retort coke, coal, anthracite, or charcoal with a binder are graphitized by electric heating. The parts may be given a prior impregnation, in an atmosphere of nitrogen, hydrogen, carbon monoxide, or illuminating gas, with a metal or a metal compound, e.g. (1) molten metal sulphides and/or selenides; (2) solutions of copper, lead, or silver salts which are subsequently transformed to sulphides or selenides by the action either of hydrogen sulphide or selenide or of solutions of polysulphides or polyselenides; or (3) a solution of an alkaline polysulphide or polysehenide followed by treatment with a metal or a metallic solution. The parts are then washed, dried, impregnated with the condensable or polymerizable substance, heated to evaporate volatile matter, and further heated to modify the impregnant. The Specification as open to inspection under Sect. 91 comprises also carrying out the two impregnations in reverse order or in combination; thus the part is impregnated: (a) with a solution of an alkali metal polysulphide in an alcohol-water mixture, a fatty acid having at least two sets of conjugated double bonds, and a metal soap, e.g. stearate or palmitate, when subsequent heating effects simultaneous sulphurizing and hardening; (b) with molten lead and a fatty siccative oil containing dissolved sulphur followed by heating to 180 DEG C.; or (c) with a siccative oil containing a metal soap with treatment with hydrogen sulphide and/or selenide. A further impregnation with sulphur or selenium in an organic solvent may be made. The finished parts may have anti-oxidants incorporated therein and may be coated with lubricants. This subject-matter does not appear in the Specification as accepted.