Yayınlarımız

Friction and wear characteristic of friction materials s used in vehicles’ brake systems have great importance for safe braking performance. Friction materials should exhibit adequate and stable friction coefficient and should have minimum sensitivity to brake operating parameters.Considering these requirements composite friction materials have become recently one of the most important group of friction materials. They consist of four types of ingredients: fibres, binder, fillers and friction modifiers, and these ingredients have different effects on friction performance of composite friction materials.Among them, binder (phenolic resin) is one of the most important ones since it firmly binds all additives in the composite andhas a significant effect on the friction performance of the composite. Therefore, it is very important to determine the accurate amount of resin in the composite matrixin order to prevent any deterioration of friction performance and mechanical properties of composite friction material during its usage. In this study, resin content of a composite friction material was optimized for a specific matrix composition in order to achieve the best combination of tribo-performance and mechanical properties.For this purpose, different amount of resinranging between 16 wt.% and20 wt.% were added to the matrix by changing only the filler (barite) contentof the composite.  Subsequently, friction and wear behavior of the samples were analyzed  using a pin-on-disc type test rig developed for testing of brake pad materials (Brake Pad Friction Tester, www.uts-design.com). After the tribological tests, the worn surfaces of the samples were scanned using a 3D surface profilometer to analyze friction andwear characteristics of the samples in detail. The results demonstrated that the average friction coefficient of composite and temperature of the disc surface showed a linear increase with decreasing the resin content. The composite having 20 wt.% resin showed the minimum wear rate with smooth worn surface that was almost entirely covered with secondary plateaus, i.e. the amount of fade is quite high.As the amount of resin in the composite structure decreased, fade formation also decreased, and  the composite structure with 16% resin brought about the minimum fade formation. As the fade formation is unwanted in brake pad applications, the composite with the lowest amount of resin (16 wt.%)  was proposed to be the most appropriate oneconsidering the performance parameters related to friction and wear.

Keywords:Non-asbestos composites brake pad, binder, friction materials, friction and wear.