Papers by Keyword: ZnO Whisker

Abstract: Wave-absorbing coating samples are fabricated with ZnO whisker, the absorbent and silicon resin coating as the binder.The influences of the content of ZnO whisker in the absorbing coating and the thickness of the coating on millimeter wave absorbing property are analyzed.With the increasing of the thickness, the absorbing performance of the sample is enhanced significantly , the results show that with a ZnO whisker mass of 50% and coating thickness of 2 mm, excellent absorption (R<-10dB) is observed in the wave band from 66 to 78 GHz (with a bandwidth of 12GHz) . When the ZnO whisker mass is reduced to 30% with the same thickness of 2mm, two absorption bands are obtained from 55 to 67 GHz (with a bandwidth 12GHz) and 100 to 110 GHz (with a bandwidth 10GHz). Maxwell equations and boundary conditions are used to analyze the absorbing mechanism of the coating.

Abstract: This article is intended to outline a novel concept of interlaminar 3-3 connectivity of fiber-reinforced laminated composites. This microstructure is typically realized by using thorny ZnO whiskers exactly located in the interlayer of glass or carbon fabric for RTM. From the initial testing, the interlaminar shear strength (ILSS) is noted to increase up to 150% while retaining the most other in-plane properties. Mechanistic penetrating and pinning are considered to be the dominant mechanism of interlaminar toughening effect, with the evidence of the broken, fragmented and pull-out whiskers observed in the fracture morphologies.

Abstract: Glass fiber reinforced polymer composites were prepared by dispersing zinc oxide (ZnO) whiskers in resin matrix. Static and dynamic tensile tests of the as-prepared composites were performed by means of a universal testing machine and the split hopkinson tensile bar (SHTB), respectively. Good tensile properties, which can be affected by the strain rates, of the composites are obtained. The fracture section morphology of the composites was investigated by scanning electron microscope (SEM). The different failure of the composites under static and dynamic tension is found. The tensile properties of the composites are dominated by pull-out and fracture of fiber bundles. The influence of ZnO whiskers on the performance of composites has been discussed. ZnO whiskers, which have unique three-dimensional structures and corresponding stress transfer, contribute to the tensile properties of the composites.

Abstract: A process is adopted to grow whiskers on carbon fibers. The whisker growth is carried out in a two-step process. Plasma spraying, electroplating and magnetron sputtering are used to pretreat the surface of carbon fibers and then ZnO whiskers are grown by hydrothermal method. By comparing three different methods of surface pretreatment, it is concluded that magnetron sputtering is most available and has no damage to the carbon fibers. Combining preparation method of the ZnO whiskers, a new process is developed to surface modified of carbon fibers which is expected apply to carbon fiber composites.

Abstract: A type of basalt fibers polymer functional composites embedded with ZnO whiskers was prepared. The as-prepared composites exhibited good microwave absorption properties after the dispersion of ZnO whiskers in resin. The dynamic compressive properties of composites were investigated by the split Hopkinson pressure bar (SHPB) system. The macro- and micro-fracture morphology of composites was obtained by the scanning electron microscope (SEM). The experimental results showed that the as-prepared composites have excellent mechanical properties, and the compressive properties could be significantly affected by the strain rates in the in-plane direction, as well as in the normal direction. As the strain rate increased, the higher strength and elastic modulus are obtained. Under the dynamic compressive load in the normal direction, the main failure mode of composites is pure compression. On the other hand, longitudinal splitting and delamination of composites could be induced when loaded in the in-plane direction. The micro- interfacial crack, fiber fracture and plastic deformation of resin could be observed from the morphology of fractured composites.

Abstract: Calcium phosphate cement (CPC) is a self-hardening material for bone repairing. ZnO whisker is a new type reinforced materials lately, which is acerose single crystal fiber. In this study, ZnO whisker was added into the CPC with different ratios, and each specimen kept at 37 oC in 100% humidity for 24 hrs. The phase and microstructure of the calcium phosphate pastes were investigated using X-ray diffraction and scanning electron microscopy, respectively. It has been found that ZnO whisker could supply nucleating center, TTCP and DCPA could be much easier to form HA around the ZnO whisker. The adding amount of ZnO whisker is a key factor that determines the mechanical properties.

Abstract: The friction and wear behavior of nylon1010 composites filled with different proportions of ZnOw in reciprocating sliding against GCr15 steel ball under dry friction condition were studied. The worn surface and wear particles were then examined with SEM. The elastic modulus, nano-hardness and ball indentation hardness of composites increased with the content of ZnOw. The coefficients of friction of composites decreased lightly, which changed from 0.36 and 0.26 of nylon matrix to 0.30 and 0.22 of composites at 0.04 m/s and 0.08m/s sliding velocity, respectively. The anti-wear property of composites was improved with large extent. The typical wear mechanism of nylon matrix is adhesion and micro-melting. However, peeling of surface layer appears owing to fatigue for composites. Roll-shaped wear debris were produced for pure nylon, while flake-like debris for nylon composites.