Research On Brake Composites Reinforced With Calcium Sulfate Whiskers

New whiskers with the high cost performance provide more options for thedevelopment of non-asbestos vehicle brake materials. In this paper, the brake materialsbased on anhydrous calcium sulfate whisker reinforced the phenolic resin matrixcomposites are made by hot press forming. The influence of whiskers contents on frictionand wear properties is studied by JF150-Ⅱ friction&wear tester and the Link-Chase tester.The interaction of whiskers with the resins and frictional additives is researched byorthogonal experiment; the TG&DSC experiment is taken by Pyrisi-Ⅰ.In order todiscover the influence of whiskers contents on wear mechanism of friction material underdifferent temperatures, the morphologies of rubbing surface of samples with differentwhiskers contents are observed by SEM, and the constituents and phases of abrasive dustare analyzed by EDS.The single-factor experiments of whiskers contents show that, the friction coefficientsfluctuate within a narrow range under250℃. The lowest friction coefficient appearedwhile the ratio of whiskers and resin is1:1. but when beyong300℃，the wear rate becomestable and the heat-fade is restrained effectively while the ratio of whiskers and resin is1.5-2.5. The TG experiment show that the decomposition temperature of the samples canbe raised about100℃with adding of whiskers, and the amounts of residuals are increasedabout30%in600℃.Orthogonal experiments indicate that, the impact of whisker on the composites’ wearproperties is mainly through the interaction of whiskers and fillers. The interaction ofwhiskers and copper particles has a significant effect on wear rate of the samples, and theinteraction of whiskers and Al2O3particles has a significant effect on friction coefficient ofthe materials.The fiction and abrasion mechanism analysis discover that, the whiskers have anotable influence on wear mechanism of resin matrix composites. The whiskers caneliminate the heat-fade of composites by reinforcing the matrix, so as to acquire thesuitable and stable friction and wear performance and improve the service life effectively.The industrial experiments of optimization formula show that, the samples have welltribology capability while the content of the whisker is45%(wt). The sample can beclassified as FF level, meet the working acquirement completely. The stability of heat-fade test is above90%, the stability of recovery test is till98%, its wear rate is only6.5%(wt)and the wear mechanic is stable.