Change of the friction coefficient as a function of the composite brake disc temperature in the test rig trials

The paper presents results of testing a friction pair on the KRAUSS test rig. The trials have been conducted on the composite MMC brake discs together with the commonly used OMC friction materials. Discs were made of the aluminium based composites reinforced with a silicon carbide (SiC) andfly ashes from the power station. The friction characteristics obtained presented in a form of friction coefficient graphs as a function of temperature, enable to indicate limitations in the application of these devices in comparison with the cast iron discs. The tests have been conducted on the KRAUSS test rig in the real scale using non-ventilated brake disc and „Bendix" callipers for the passenger M1 category car. Brake discs are characterised by: high value of the friction coefficient, low wear of the friction area following tests, high thermal resistance. Brake discs tested, made of MMC: -ALFA (AK9 + 20 % vol. fly ash are characterised by: low friction coefficient mi is lower than 0.3 and high wear of the brake disc surface following tests. Characteristics show large discrepancies of the friction coefficient value between each braking cycle. Composite Al alloys based brake discs reinforced with SiC (20 and 30 % vol.) may find application in the light sports cars and quads 3 and 4 wheeled.