Jizhong Zhang

Effect of inorganic–organic interface adhesion on mechanical properties of Al2O3/polymer laminate composites

Abstract Al2O3/polymer laminate composites were studied by using different surface treatment techniques and different resins. The silane coupling agent TEVS (triethoxyvinylsilane: CH2CHSi(OC2H5)3) was used to enhance the inorganic–organic interface adhesion. The inorganic-organic interface shear strength, the flexural strength, and the work of fracture of the laminate composites were measured through tensile test and three-point bending test. The morphology of inorganic surface and crack propagation was examined by SEM and AFM. The relationship between inorganic-organic interface shear strength and the work of fracture of the laminate composites was investigated. The experimental results suggest that the toughness of the laminate composites related closely to surface status of the matrix, couping agent, and resin. The maximum value of the work of fracture of the laminate composites was 6.1 times that of monolithic alumina. The work of fracture of the laminate composites, which alumina matrices were coated with a layer of epoxy vinyl ester resin (UPR 3201), increased gradually with increasing the interface shear strength. The work of fracture of the laminate composites, on which alumina matrices were coated with a layer of toughened epoxy vinyl ester resin (T-UPR 3201), decreased greatly as the interface shear strength increased.

Radiation damage and wettability change of low energy C+ implanted polytetrafluoroethylene

The surface modification of polytetrafluoroethylene (PTFE) was carried out by carbon ion implantation. The influence of implantation parameters was investigated by varying ion dose over a wide range. The samples were implanted with 20 keV carbon ion with doses from 5 x 10(15) to 5 x 10(17) ions cm(-2), and examined by ESCA, XRD, SEM, and wettability. Five chemical bonds were formed on the surfaces of as-implanted samples, and their content changed as a function of ion dose. The crystallinity of the as-implanted samples increased gradually with increasing ion dose. Various radiation damage structures were observed. The values of droplet contact angle of the as-implanted samples increased gradually with increasing ion dose, and was very sensitive to the environmental humidity under which the droplet contact angle was measured. The experimental results show that the surface chemical bond, crystallinity, morphology, and wettability of as-implanted PTFE samples are closely dependent on the carbon ion dose

Influence of aging on the morphology and wettability of polytetrafluoroethylene implanted by high-fluence carbon ion

Polytetrafluoroethylene (PTFE) was implanted by 40 keV carbon ion in a Metal Vapor Vacuum Arc (MEVVA) implanter. The influence of implantation parameters was studied by varying ion fluence from 5 x 10(15) to 5 x 10(17) ions/cm(2). Characterization of the as-implanted samples was performed by electron spectroscopy for chemical analysis (ESCA), scanning electron microscopy (SEM), and wettability. With increasing ion dose, various chemical bonds and irradiation-damaged structures were observed, and droplet contact angle of the samples increased gradually. All the as-implanted PTFE samples were aged in air for 1 year. After aging the surface-restructuring behavior was observed on the surfaces of the samples implanted with ion fluences equal to or less than 5 x 10(16) ions/cm(2). The experimental results revealed that ion fluence strongly affected the surface chemical composition, morphology, and wettability of the as-implanted samples, as well as the aging stability

Structure and properties of molybdenum implanted with high-flux carbon ion

High purity molybdenum was implanted by C ion in a metal vapour vacuum arc (MEVVA) implanter. The influence of implantation parameters was studied by varying ion fluence and ion current density. The samples were implanted by 45 keV C ion with fluences from 1 x 10(15) to 1 x 10(18) ions/cm(2), respectively. The as-implanted samples were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and nanoindenter. Different morphologies were observed on the surfaces of the as-implanted samples due to irradiation damage, and clearly related to implantation parameters. XRD spectra confirm formation of beta-Mo2C with ion fluences equal to or larger than 1 x 10(16) ions/cm(2), and formation of alpha-Mo2C with ion fluence of 1 x 10(18) ions/cm(2). The maximum nanohardness and maximum modulus of the as-implanted samples increased gradually with increasing ion fluence, and reached the corresponding maximum values with ion fluence of 1 x 10(18) ions/cm(2). The experimental results suggest that the structure and properties of the as-implanted Mo samples exhibited strong dependence on implantation parameters