TIMREX® Graphites and Cokes for Friction Materials - Timcal

Applicationproperties ofmodel brakeliningsGraphite and cokein sintermetallicfriction materialsResults and ConclusionsBoth for KS and T graphites, a rise in thefriction coefficient commensurate with thegraphite grain size was ascertained. In particular,a reduced proportion of fine grains inthe graphite grain band (KS 5-75TT,KS 150-600SP) led to an increase in the frictioncoefficient with simultaneous reductionof abrasion of the lining. A frequent, undesirableside-effect, however, is an expansion ofthe friction coefficient range (minimum µ -maximum µ). By adding a tiny quantity offine graphite powder the properties of thefriction lining can be optimised.Friction coefficient µFriction coefficient µ0.70.60.50.40.30.20.10KS 6 KS 15 KS 44 KS 75 KS 5-75TTGraphite type0.70.60.50.40.30.20.10T 44Graphite typeKS 150-600SPT 75 T 800 T 150-600Friction coefficient of sinteredCu-C -brake pads with 10%TIMREX® KS Graphite as afunction of the particle sizeSinterconditions: 850°C, 3 hSinterdensity: 55% of the theoret. densityFriction coefficient of sinteredCu-C -brake pads with 10%TIMREX® T Graphite as afunction of the particle sizeSinterconditions: 850°C, 3 hSinterdensity: 55% of the theoret. densityWhere grain sizes were identical, the Tgraphites were generally observed to havehigher friction coefficients than model liningswith KS graphites. The higher friction coefficientsof T graphite linings cause greater wearof the linings, however.Friction coefficient µ0.70.60.50.40.30.20.10 0T 150-600KS 150-600SPGraphite type0.70.60.50.40.30.20.1Wear (mm)Friction coefficient and wear of sinteredCu-C -brake pads with 10%TIMREX® KS 150-600SPand T 150-600 GraphiteSinterconditions: 850°C, 3 hSinterdensity: 55% of the theoret. densitywear