Patent GB-749759-A (GB)
Title: Improvements in or relating to process of making an alloy and frictional composition and the resulting product
IPC: C22C9/00
Filed: 1953-04-02
Abstract: A composition of a powdered alloy of lead with copper and/or silver (see Group II), a resin carrier and a solvent, is suitable for self-lubricating coatings or friction surfaces such as brakes or clutches or for heat and electricity conducting coatings on electronic tubes.  The resin may be a mixture of polymerizable phenolic type 65-95 per cent and a thermoplastic type 5-35 per cent such as chlorinated styrenes, synthetic rubber and waxes. Chlorinated diphenyl may be included together with dimethyl-cetyl-lauryl ammonium bentonite and thinners such as toluene and xylene.  The composition may be applied by spray or brush and air dried.ALSO:A composition suitable for self-lubricating coatings on friction surfaces such as brakes or clutches or for heat and electricity conducting coatings on electronic tubes comprises a powdered alloy of lead with copper and/or silver (see Group II). The alloy powder which may be of grain size 200-900 mesh may be mixed with a resin, in the proportion 1/8 -10 lbs. of alloy to 1 gallon of resin, and a resin thinner, the mixture being applied to the surface to be treated by a spray gun, the thickness of the coating being e.g. 0.0005-0.005 inch, and the coated article is then baked at a temperature in the range 250-500 DEG F. The resin carrier may be a mixture of polymerizable resin of the phenolic type, 69-95 per cent., and a thermo-plastic resin, 5-35 per cent.  Alternatively the alloy can be incorporated in a composition which is applicable by brushing on and air drying. Such a composition is made by dispersing the powdered alloy in a carrier of chlorinated rubber or chlorinated thermoplastic and a chlorinated organic aryl resinous compound such as chlorinated diphenyl together with a mutually compatible solvent.  For example 9 parts of chlorinated latex of viscosity 100-1000 centipoises containing in solution about 1 part of chlorinated diphenyl of melting point 100-105 DEG C. is thinned with 90 parts of toluene or xylene.  One part of alloy is then mixed with 1.8-2.0 parts of the vehicle to give a composition which can be applied with a paint brush.  A lacquer type solvent may be used in place of toluene or xylene.  Chlorinated synthetic rubber or chlorinated thermoplastic resins obtained from styrene or chlorinated paraffins known as chlorowaxes may be used in place of chlorinated rubber.  The composition may also contain an organic derivative of hydrous aluminium silicate such as di-methyl-cetyl-lauryl ammonium bentonite in amount of 1.5-2.0 per cent of the total volume of the vehicle.ALSO:A process of making a completely homogeneous alloy of lead with copper and/or silver comprises introducing the lead into a molten mass of copper and/or silver which is covered by a protective flux of haematite and stirring the melt while applying heat to bring the temperature of the melt back to that of the copper and/or silver before the addition of lead, e.g. up to 2600 DEG F.  Preferably lead is added in successively small portions the temperature of the melt being restored after each addition. The ore used as flux may have admixed with it 0,25-2 per cent of silica and 0,25-5 per cent of ammonium chloride with or without 0,25-3 per cent of sodium carbonate. Charcoal in amount equal to approximately, 1,5 lbs. for each 100 lbs. of resulting alloy may be added to the melting crucible.  Preferably half the charcoal is added to the empty crucible and the remainder after the copper has been added.  The amount of flux used may be 1 to 5 lbs. for each 100 lbs. of alloy.  After alloying, the temperature is held at near the upper limit of the range for a short period, the slag is skimmed off and the alloy is poured into moulds.  The alloy may contain lead in the range 30-70 per cent, e.g. lead 50 per cent with copper 25-44 per cent and silver 6-25 per cent. Other metals such as chromium, nickel and tin may also be present in amount up to 10 per cent, the additional metal being first alloyed with copper at a temperature of 300 DEG F. above the melting point of the higher melting metal, this alloy being then used in place of copper for alloying with lead.ALSO:A composition suitable for self-lubricating coatings on friction surfaces such as brakes or clutches or for heat and electricity conducting coatings on electronic tubes comprises a powdered alloy of lead with copper and/or silver (see Group II). The alloy powder which may be of grain size 200-900 mesh may be mixed with a resin, in the proportions 1/8 -10 lbs. of alloy to 1 gallon of resin, and a resin thinner, the mixture being applied to the surface to be treated by a spray gun.  The resin carrier may be a mixture of polymerizable resin of the phenolic type 65-95 per cent., and a thermo-plastic resin, 5-35 per cent.