| Resin matrix composite material acting as an important component of wet friction material is widely used in automobile automatic transmission, synchronizer, differential mechanism and torque manager, etc. Along with the advance of technology, the drive/brake system in high-speed railway, subway, large engineering machinery and deep sea oil drilling has put forward more stringent requirements of the resin matrix composites in the operation condition, driving stability and service life. This paper studied the influence of different modified phenolic resin and the dual material on the tribological properties of carbon fabric reinforced wet friction material. It was mainly focused on the modification of carbon fabric by hydrothermal oxidation and microwave hydrothermal method to deposit Si O2.(1) Three kinds of carbon fabric reinforced wet friction materials were prepared with boron-modified, cashew nut shell liquid modified and nitrile butadiene rubber modified phenolic resin. The degradation characteristics were analyzed using a thermal analyzer. The friction and wear properties were tested by a wet friction performance tester. Scanning electron microscopy(SEM) was also employed to study the wear mechanisms. Experimental results indicated that the samples with boron-modified phenolic resin demonstrated better potential with good heat-resistance, high friction coefficient, excellent friction stability and low wear rate.(2) Carbon fabric was treated by HNO3 under different hydrothermal temperatures. The tribological properties were also studied. Experimental results showed that the carbon fabric treated by hydrothermal oxidation led to changes in fibers surface morphology and carbonyl groups appearance. Carbon fiber graphitization degree increased, and carbon fabric surface hydrophilicity was improved obviously, which effectively improved the bonding strength of carbon fabric and resin. Moreover, hydrothermal oxidation treatment of carbon fabric reinforced wet friction material showed the best wear properties appeared at 100℃and 120℃, at which the wear volume reduced to 34.3% and 44.7% compared to the unmodified sample, respectively.(3) Under 100 ℃ hydrothermal treatment, nano-Si O2 particles were introduced into the system by microwave hydrothermal method with different temperatures, concentration of silica sol and reaction time. The effect of nano-Si O2 particles on carbon fabric reinforced wet friction material was studied. The results indicated that nano-Si O2 particles were successfully deposited onto carbon fabric surface under a microwave-hydrothermal condition, which obviously improved the carbon fabric surface roughness and hydrophilicity, realizing the multi-scale enhancement of the composite material. The best wear property appeared at 200℃ for 60 min with the 9% concentration of the silicon sol. The dynamic friction coefficient and the friction stability were improved. The wear volume reduced to 20.8% compared to the unmodified sample.(4) Under 100℃ hydrothermal treatment, the friction and wear properties were carried on with 45# steel, Cr12 steel, stainless steel, copper as mating materials. The effect of different mating materials on carbon fabric reinforced wet friction material was studied. The results showed that when copper worked as the mating material, copper gradually transmitted from the steel counterpart surface to the friction material surface in the process of wear and tear, mainly as adhesive wear, greatly reducing the damage to friction materials; With 45# steel worked as mating material, friction material was mainly showed as abrasive wear and adhesive wear, and the wear-resisting properties declined; While carbon fabric reinforced wet friction material appeared a lot of fiber fracture phenomenon with stainless steel or Cr12 steel for mating material. The wear mechanism led to higher wear, which was mainly composed of abrasive wear. |
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