Applied Mechanics and Materials Vols. 341-342

Abstract: In order to investigate the effects of lager notch ratio (2α/W) and loading rate on the tensile behavior of woven fabric reinforced flexible composites, in this study, fracture mechanism and tensile strength of finite woven fabric-reinforced flexible composite materials with a through-the-thickness symmetrical located double edge notches is experimentally investigated, and the effects of notch size, loading rate on the tensile properties of notched specimen are analyzed. The results show that the woven fabric reinforced flexible composites exhibit notch sensitivity and loading rate dependent. These results play an important role in predicting strength and evaluating the lifetime of textile reinforced flexible composite materials with double edge notches.

Abstract: Effects of injection molding parameters on the residual fiber length and the mechanical properties of LFRT-PP composites, which were prepared by self-designed impregnating molding, were investigated by orthogonal experimental design method. The results showed: the length of residual glass fiber increased with the length of LFRT pellets and decreased with screw speed. The former had more remarkable impact. The mechanical properties of composites were greatly affected by the temperature of barrel. The lower temperature was benefit for obtaining the higher properties. The length of residual glass fiber was not directly corresponding with the mechanical properties. To obtain the highest mechanical properties of composites, the optimal parameter levels were: the length of pellets 10mm, the temperature of barrel 220°C, the screw speed 75 rpm and the injection pressure 80 MPa.

Abstract: The nanoKNiF₃ with its particles size of 50-70 nm was prepared by solvent-thermal method and characterized by means of XRD, TEM and IR technologies. Photocatalysed reduction of aqueous Na₂CO₃ was carried out by using nanoKNiF₃ powders. Formic acid, formaldehyde and methyl alcohol were identified as photoproducts, and were measured in spectrophotometry using Nash reagent. It shows that nanoKNiF₃ has superior photocatalytic activity. Irradiation leads to the production of electrons in the conduction band of the KNiF₃ nanoparticles. It is likely that the photoproduced electrons reduce CO₃^2- initially to HCOO^-, and then to HCHO and CH₃OH.

Abstract: The complex fluorides BaCoF₄ and BaCoF₄: Ce³⁺ were synthesized by reflux method in ethylene glycol and characterized by means of XRD, TEM, XPS, UV-VIS and Fluorescence Spectrophotometer. In addition, the photocatalytic degradation property of BaCoF₄: Ce³⁺ was investigated. The results indicated that the mean particle diameter of BaCoF₄ was 54.6 nm. Only adsorption oxygen (α oxygen) existed on the surface of BaCoF₄ and the content of surface oxygen was 5%. The BaCoF₄: Ce³⁺ had a stronger absorption at 250 nm, which could be explained by d electronic transition of Ce³⁺. The maximum emission peak of BaCoF₄: Ce³⁺ was 361.8 nm in its luminescent spectrum, and emission band of Ce³⁺ belonged to 5d4f transition. Meanwhile, the degradation rate of acid red 3B by BaCoF₄: Ce³⁺ reached 98.7% after being lightened for 2 h by a 450 W high pressure mercury lamp.

Abstract: CaZr₄(PO₄)₆ ceramics were prepared with solid reaction of two-steps method. CaZr₄(PO₄)₆ powders were synthesized by solid-phase reaction with Ca (OH)₂, ZrO₂ and (NH₄)₂HPO₄ as raw materials. Then the powders precursor were sintered to CaZr₄(PO₄)₆ ceramics with single phase structure at 1400°C for 8 hours. The relative density was measured, the phase structure of the materials synthesized at different temperatures and the average coefficients of thermal expansion were investigated. The results showed that the relative density of CaZr₄(PO₄)₆ ceramics sintered at 1400°C was 93%. The average thermal expansion coefficients was 1.8×10^-6/°C from 25°C to 1400°C. The CaZr₄(PO₄)₆ ceramics obtained possesses low thermal expansion property in a broad range of temperatures.

Abstract: Metastable crystal Bi₂SiO₅ has significant properties including dielectric, thermoelectricity and nonlinear optical properties. Metastable crystal Bi₂SiO₅ has been successfully prepared by melt cooling method in this study. Surface tension of high-temperature melt Bi₂SiO₅ was measured by Suspension method; metastable crystal Bi₂SiO₅ construction was assigned by IR(Infrared Radiation). The experimental result showed that Bi₂SiO₅ flux density decreased with the increasing temperature in 830-1095°C range; surface tension changed quadratic with the decreasing temperature. The [SiO₄]^4- anions of Bi₂SiO₅ originated from the isolated [SiO₄] tetrahedron in the glass to a chain connected structure.

Abstract: In order to study the properties of Ti (CN) ceramic coating, nitrogen arc cladding technology was carried out using TXII500 argon arc cladding machine in nitrogen gas atmosphere, and TiCN based composite coating was preparated on the Q235B specimen surface which is precoated titanium powder and graphite powder. The molten coating was tudied under the cladding current respectively in 200 A, 220 A and 240A. The microstructure, phase composition, micro hardness and wear resistance were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), microhardness tester and reciprocating friction testing machine. The results show that the generation of the Ti (CN) phase is the most when the cladding current is 200A, The microscopic hardness of the coating is reduced with the increase of current, which provides a theoretical basis for the optimization of the process further.

Abstract: The metal ceramic coating of TiAl (CN) by nitrogen-arc cladding technology was produced on the surface of 45#steel.The phase composition of coating was analyzed with X-ray diffractometer; The bonding state and microstructure were observed with scanning electron microscope; The microhardness was examined and the wear resistance of the metal ceramic coating compared with that of 60Si2Mn steel treated by quenching and tempering was tested by abrasive tester as well. The results indicated that the TiAl (CN) ceramic particle synthesized in-situ is distributed dispersively in the cladding and the size is under 3 um. The excellent bonding between the coating and 45# steel substrate is strengthened by the strong metallurgical interface; the coating is uniform and continuous. The maximum microhardness of cladding is HV_0.21820 and the abrasive performance is better than 60Si2Mn steel treated by quenching and tempering. The simulation test results showed that the cladding is good, and can be used to the repair and remanufacture for wearable parts of stubble-cleaning cutter.

Abstract: Metal composites coating of Ti (CN) was made on the surface of Q235 steel substrate by reaction nitrogen are welding cladding process, and potted with low temperature epoxy, di-n-butyl phthalate and T31, the mass ratio was 10:2:1.5. To evaluate the corrosion resistance of Ti (CN) coating, the specimens were immersed in 5% sulfuric acid and 3.5% sodium chloride to calculate corrosion rate by potentiodynamic polarization measurement. The corrosion resistance of Ti (CN) is improved by 3.45 times in 5% sulfuric acid and 4.39 times in3.5% sodium chloride.

Abstract: Using plasma spraying equipment to prepare Al₂O₃-13wt%TiO₂ coating on Q235 substrate. Study of its organization and performance, test the performance of coating microhardness and the resistance of friction and wear resistance then optimize the spraying process parameters. The surface of the coating performance was studied by SEM. The results show that, Coating microhardness can be as high as 1132HV, Far more than the matrix microhardness. The minimum average wear weightlessness of Sample surface is 0.95mg. Greatly improve the wear resistance