TIMREXÂ® Graphites and Cokes for Friction Materials - Timcal

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www.timcal.comApplicationproperties ofmodel brakeliningsGraphite and cokein organic bondedfriction materialsResult and conclusionAs graphite concentration decreases, thefriction coefficient rises and finally reaches aconstant value at 20% graphite. Fine-grained,flaky, nat. graphite 1, is an exception with afurther increase at 10% of graphite. Frictioncoefficient fluctuations are largely constantfor all graphite concentrations, and increasemarginally at 10%. The start-up period tosteady conditions decreases with reducinggraphite concentration.The test material with 10% T 200-2000does not appear to have an instable start-upperiod, and reaches the required frictionlevel immediately with the least frictioncoefficient fluctuations.Wear characteristics vary considerably fornatural graphites and TIMREX ® T 800 andT 200-2000 graphites. With TIMREX ®Graphite friction materials, wear reduces atlower graphite concentrations, but tends toincrease with natural graphites. In the concentrationrange of around 10%, which isof interest to the user, TIMREX ® Graphitefriction materials demonstrate less wear.We therefore recommend the T 800 andT 200-2000 coarse graphites for use inorganically bonded brake linings.T 150-600 is particularly suited toachieving specific grain densities. By reducingthe proportion of fine grain in thegraphite powder, extra space is availablebetween the coarse graphite particles so thatother fine fillers such as oxides, sulfides,baryte or cokes can be added.Friction coefficientµ-level0,50,40,30,20,1WearSpec. wear rate s.w.r.0,0250,0150,010,005nat. graphite 1 T 800 nat. graphite 2 T 200 - 2000080 40 20 10 80 40 20 10 80 40 20 10 80 40 20 10Graphite type / graphite content (%)0,020nat. graphite 1 T 800 nat. graphite 2 T 200 - 200080 40 20 10 80 40 20 10 80 40 20 10 80 40 20 10Graphite type / graphite content (%)Friction level of test samples as afunction of graphite type and graphiteconcentration after the periodof bedding, friction load: 15 lbsCourtesy: ITT AutomotiveS.W.R. of test samples as a functionof graphite type and graphiteconcentration.Courtesy: ITT Automotive
Applicationproperties ofmodel brakeliningsGraphite and cokein organic bondedfriction materialsTIMREX ®Graphite has found its placein the field of friction materials as areliable, high quality product. Manyproblems can be solved thanks to thebroad range of TIMREX ®Graphites.Our specialists will be glad to help youin the selection of the most suitableproduct for your application.CokeCoke powders are used as frictionmodifiers, and should fulfill the followingprinciple functions:Reduce weight by using a filler withlow specific weight.Set the required total concentrationof carbon by volume (graphite and coke).Reduce fading.Reduce wear and tear of the lining.Friction coefficient µ / aver. val.FC250 FC400 FC800 FC250-1500Coke typeAverage friction coefficient of TIMREX®Cokes in model brake pads(90% coke, 10% phenolic resin,compacting pressure: 200 bar,curing temperature: 160°C)MethodTest samplesModel brake padsFormulation 90% coke, 10% Phenolic resinThickness 12 mmTemperature (°C); hydr. pressure (bar)500 0.64000.50.43000.32000.210000.100 0.1 0.2 0.3 0.4 0.5 0.6 0.7Time / stopsFriction coefficient µT-discfrictioncoefficientT-brakehydr. pressureSurface areaTest equipment:35 cm 2DynamometerSpecial TIMCAL procedure(modified VW-Audi test)TIMREX ® Cokes are characterised by ahigh friction coefficient and low wear - especiallyby contrast with other petroleum andmetallurgical coal cokes. The friction coefficientof the brake lining can be influenced bythe grain size of the TIMREX ® Coke. A constantfriction coefficient throughout a widetemperature range, and excellent fadingbehaviour during successive stop brake applicationsis of importance to the user.Fading behaviour of FC 250-1500 inmodel brake pads (90% coke, 10%phenolic resin,compacting pressure: 200 barcuring temperature: 160 °C)
Page 1 and 2: Graphites and Cokesfor friction mat
Page 3 and 4: Graphite andCoke Powdersfor Brake L
Page 5 and 6: Particle shapeAdvantages and applic
Page 7 and 8: Particle shapeAdvantages and applic
Page 9 and 10: GraphiteProperties:Density and inte
Page 11 and 12: GraphiteProperties:Thermal conducti
Page 13 and 14: Coke Properties:Coke structureThe s
Page 15 and 16: Applicationproperties ofmodel brake
Page 17: Applicationproperties ofmodel brake

TIMREXÂ® Graphites and Cokes for Friction Materials - Timcal

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