Preparation And Properties Of The Composite Friction Materials By Adding Carbon Fiber Wastes

With the development of the carbon fiber industry,more and more carbon fiber products have been widely used in China.At the same time,the carbon fiber waste is also increasingly accumulated.The highly efficient recycling of the carbon fiber waste has become an urgent problem.The carbon fiber reinforced composite friction materials have excellent overall performance,so they can match the needs of the automotive braking well compared with the traditional friction materials.However,due to the relatively high cost,the application of the carbon fiber reinforced composite friction material is limited in the field of the industrial brakes.The utilization of the carbon fiber waste is a promising and marketable technology to prepare the high quality friction materials.In this paper,the composition of the friction materials with carbon fiber waste was designed and prepared.using phenolic resin blended with NBR powder as binder,carbon fiber,steel fiber,and aramid fiber as reinforcement,carbon fiber woven fabric waste and carbon fiber fishing rod waste as one of the components of friction materials.The effects of phenolic resin type and two waste materials on the performance of friction materials were studied.The microstructure of the material was studied by scanning electron microscopy,and the hardness,impact toughness and friction wear properties of the material were tested.The main results are as follows.The effect of four types of phenolic resins on the properties of the composite friction materials was investigated.The results demonstrated that the friction materials prepared by adding different phenolic resins showed typical"island"characteristics.The as-sintered composite was a dense material,with uniform dispersion of various fibers and filler particles,as well as good distribution and dispersion of carbon fibers.The properties of friction materials prepared from four phenolic resins were different.The friction material prepared by adding PF211 resin had a high friction coefficient and good wear resistance.The effect of carbon fiber woven cloth scrap content（0-10 wt.%）on the mechanical and friction and wear properties of the friction material was investigated.The results demonstrated that the carbon fiber woven cloth scrap could improve the mechanical properties of the resin-based friction materials.The hardness and impact toughness increased with the rise of the woven cloth scrap content up to 0.283 J·cm^-2 and 102.1 HRL.The addition of carbon fiber woven cloth scrap had a slight effect on the overall friction coefficient trend.The friction coefficient had a certain reduction.The stability of the friction coefficient of the material increased while the total wear rate decreased.In the experimentally designed formulation system,the friction specimens with 8 wt.%carbon fiber woven cloth scrap exhibited better performance.The effect of carbon fishing rod scrap on the mechanical and friction and wear properties of friction materials was experimentally studied.The results showed that the impact strength increased with the rise of carbon fishing rod scrap content.Its hardness decreased firstly and then increased.The friction coefficient increased with the content of fishing rod scrap and decreased when the number of scrap addition amount reached 10 wt.%.Moreover,there was an obvious fade phenomenon in the high temperature stage.The addition of the scrap reduced the total wear rate and significantly improved the wear resistance of the friction material.The friction stability of the material showed an increase trend first and then a drop with the rise of the fishing rod scrap.In the system,the addition of 6 wt.%of carbon fishing rod scrap had the best overall performance.