A novel idea was implemented to grow aligned ZnO nanorods on carbon fabric by directly chemical bonding to form a multi-scale reinforcing resin composite. The aligned ZnO nanorods/carbon fabric were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectra and X-ray photoelectron spectroscopy, indicating an existence of chemical bonding (C-O-Zn) between ZnO nanorods and carbon fiber. The tensile and inter-laminar shear strength (ILSS) of ZnO nanorods/carbon fabric/resin composite (C1) were 182.4 and 147.1 MPa, which increased by 27% and 134% compared with bare carbon fabric/resin composite (CO), respectively. And the sample C1 possessed lower compressibility and higher recovery. As a result, the sample C1 obtained the high and stable friction coefficient. The wear rate of sample C1 decreased by about 38% compared with that of sample C0. The analysis of the worn surface by SEM and EDS showed that the ZnO nanorods were polished gradually and then fractured without peeling off as a whole from carbon fiber leading to excellent tribological performance. The development of an aligned interphase offering good interfacial bonding between carbon fabric and resin matrix will provide a means to produce multi-scale reinforcing resin composite with outstanding tribological performance.

Nano-SiO2 was grafted onto the carbon fabric surface under microwave-hydrothermal condition to improve the tribological properties of carbon fabric/resin friction materials with different treatment temperature. The carbon fibers and prepared samples were characterized by the Fourier transform infrared spectrophotometer, contact angle instrument, energy dispersive spectroscopy, universal material testing machine and field emission scanning electron microscopy. The tribological behaviors of the carbon fabric/resin friction materials were evaluated by a friction tester. The results indicated that nano-SiO2 particles were successfully grafted onto carbon fabric surface under microwave-hydrothermal condition, especially at 200℃ (contact angle was almost close to 0°), which obviously improved the hydrophilicity of carbon fabric surface. The wear rate of carbon fabric/resin friction materials with microwave-hydrothermal temperature of 200℃ reduced by 81.4%, ranging from 4.3 × 10−5 mm3J−1 to 0.8 × 10−5 mm3J−1. It could effectively enhance the bonding strength of carbon fabric and resin, which improved the friction-reduction and anti-wear abilities of the friction materials.

A series of TiO2 nanorods were successfully grown on woven carbon fiber by hydrothermal method to reinforce the resin composite. The TiO2 nanorods improved the mechanical interlocking among woven carbon fibers and resin matrix, resulting in better fibers/resin interfacial bonding. Compared with desized-woven carbon fiber, the uniform TiO2 nanorods array resulted in an improvement of 84.3% and 73.9% in the tensile and flexural strength of the composite. However, the disorderly TiO2 nanorods on woven carbon fiber leaded to an insignificant promotion of the mechanical strength. The enhanced performance of well-proportioned TiO2 nanorods-woven carbon fiber was also reflected in the nearly 56% decrease of wear rate, comparing to traditional woven carbon fiber reinforced composite. (C) 2017 Elsevier B.V. All rights reserved.

The multi-scale reinforcements of ZnO nanorods/carbon fabric with different morphologies were obtained using a simple water bath method via controlling the concentration of growth solution for a new application in wet friction materials. The ZnO nanorods/carbon fabric were characterized via X-ray diffraction, Scanning electron microscopy, Fourier transform infrared spectroscopy and Raman spectra. As a result, the ZnO nanorods/carbon fabric/resin composite (sample CP3) possesses the maximum bending and tensile strength of 62.7 MPa and 170.0 MPa, which increases by 40.2% and 59.1% compared with that of bare carbon fabric/resin composite due to the best mechanical interlocking and chemical adhesion at the interfacial region of the composite. Meanwhile, the wear rate of the sample CP3 decreases obviously by 81.5% together with stable friction coefficient under various friction condition. From view point of material design, it is necessary to control the morphologies of ZnO nanorods to optimize mechanical and tribological properties of ZnO nanorods/carbon fabric/resin composites.

In order to improve the friction and wear properties of the paper-based friction materials, SiC particles(SiCp) were uniformly deposited onto the paper-based friction material via electrophoretic deposition with 300 V, 400 V and 500 V deposition voltages, obtaining the SiCp-content of 10.8, 15.9 and 22.9 wt%. The microstructure and thermal stability of the paper-based friction materials were characterized by scanning electron microscope (SEM) and thermogravimetry (TG). And the porosity, mechanical and tribological properties of samples were tested by mercury injection apparatus, electromechanical universal testing machine and friction tester. The results show that the uniform distribution of SiCp in the paper-based friction materials decreases the porosity and obviously improves the thermal stability and mechanical properties. Meanwhile, the incorporation of SiCp increases the stability of friction coefficient and the wear resistance of paper-based friction materials. Especially, the wear rate of paper-based friction material with 400 V deposition voltage treatment (CP400) for optimal SiCp-content of 15.9% decreases by 51.2% from 5.8 x 10(-14) to 2.8 x 10(-14) m(3)/(N.m) compared with that of the bare paper based friction material (CPO). The electrophoretic deposition techniques provide the possibility of uniform addition of micro-nano particles to the paper-based friction material, which is beneficial to improve the friction and wear properties.

Uniform TiO2 array growing onto the carbon fabric (CF) resulting in multiscale reinforcement (TiO2-CF) was successfully carried out with hydrothermal method. The functions of the TiO2 array on mechanical and wet tribological properties of the carbon fabric reinforced phenolic composite were investigated systematically. The surface characteristics, including the morphology and functional groups, of TiO2-CF were evidenced by XRD, SEM, RAMAN, FTIR and XPS. The tensile strength and flexural strength of the composite reinforced by TiO2-CF improved by about 85% and 41%, respectively, which owing to the outstanding interfacial adhesion between multiscale reinforcement and matrix. Further, the resulting composites exhibited higher and more stable friction coefficient and greater wear resistance compared with the composite reinforced by desized-CF. The composite reinforced by multiscale TiO2-CF is highly promising for wet friction material.