Advanced Materials Research Vol. 625

Abstract: Compare with the conventional proton exchange membrane fuel cells (PEMFCs), high temperature proton exchange membrane fuel cells (HT-PEMFCs) have more advantages such as higher CO tolerance of catalyst, easier water management and higher catalyst activity. As the core component of the HT-PEMFC, proton exchange membrane should have excellent flexibility , thermal stability and high proton conductivity at high operation temperature and anhydrous environments. By atomic force microscope (AFM) technology, the surface topography image and lateral force image of the untreated and treated polybenzimidazole (PBI) membrane are investigated.

Abstract: Iron ore reduction and carbon deposition in pure CO was investigated by using thermogravimetric (TG) method over the temperature range of 0-1200°C. The results of the work may be summarized as follows: in CO stream, carbon deposition occurred below 900°C, no carbon deposition was found above 1000°C. X-Ray analysis of the reacted sample indicated that the carbon deposition occurred with the iron was reduced. The iron reduction process and carbon deposition occurred simultaneously. The rate of carbon deposition changed with the transformation of iron oxides. The specific surface area and pore structure of reduced samples were analyzed. The specific surface area changed with the amount of carbon deposition.

Abstract: Comprehensive utilization of oil shale with analysis of material properties is introduced in this paper, including power generation and waste rock production of oil shale, cement raw materials production of oil shale and burned rock, and road repairing. Dry distillation oil refining technology of fluid oil shale, which has reached the international advanced level, is mainly described in this paper. With this technology, a project of fluid distillation oil refining with 600000 tons of oil shale per year is going to be started in Harbin Coal Chemical Limited Company, as well as an energy saving project of producing light shale oil.

Abstract: In this paper, LiNixMn2−xO4 materials were prepared by solution combustion synthesis method using acetic salts as raw materials and acetic acid as fuel. The phase structures are characterized by X-ray diffraction (XRD). Electrochemical performances of the materials are investigated by galvanostatic charge/discharge methods. XRD results revealed that the main phase of the products with increasing Ni3+ content is LiMn2O4, and there is a trace amount of Mn3O4 found in the product with Ni3+ content of 0.05. Electrochemical experiments showed that the capacity and the cyclability of the LiNixMn2−xO4 materials decrease with increasing Ni3+ content. Ni3+ doping has no significantly improvement for the capacity and the cyclability of the LiMn2O4 spinel.

Abstract: LiFe0.05Mn1.95O4 materials were prepared by molten-salts combustion synthesis and solution combustion synthesis methods, respectively. The phase structure and compositions of the products were determined by X-ray diffraction (XRD). The main phase of the products prepared by the two methods is LiMn2O4, but at 300-600oC, pure products can not be obtained. At the temperatures of 300 and 400oC, the main impurities are MnO and Mn3O4. The impurities decrease with increasing temperatures, and finally disappear at >500oC. At 500 and 600oC, the main impurity is Mn2O3, but the relative content of Mn2O3 is low.

Abstract: Sn-Ni intermetallic compounds have been prepared by a chemical reduction method. With different molar ratios of Sn/Ni, the products are different. XRD determination results indicate that the main phases of the products with Sn/Ni=1:0.5 and 1:1.0 are Sn6O4(OH)4 and metal Sn, and the main phases of the products with Sn/Ni=1:1.5 and 1:2.0 are SnNi, Ni3Sn and metal Sn. SEM investigation finds that the particle size of the products with Sn/Ni=1:1.5 and 1:2.0 are nano size, and the particle size increases with increasing Ni content. The particles of the product with Sn/Ni=1:1.5 are in the range of 50-100nm, and well dispersed.

Abstract: The influence of carbon doping on tribological properties of CrCN Coating was studied through preparation of coatings deposited on single crystal silicon and M2 high speed steel(HSS) substrate using closed-field unbalanced magnetron sputtering ion plating technique. The friction coefficients were measured by pin-on-disc set-up. The microstructure and bond states of the coatings were characterized by X-ray diffraxtion(XRD), transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS). The results show that the friction coefficient of coating decreases from 0.75 to 0.38, the microhardness increases from 1930HV to 2302HV, and the specific wear ratio of the coatings decreases from 8.35110-5m3/Nm to 3.85910-5m3/Nm with the increasing of carbon target current(IC) from 0A to 1.5A. The analysis of microstructure shows that the coatings transform from crystalline state to amorphous state and the grain size of the coatings decreases with the increasing of carbon target current.

Abstract: A simple synthesis method of PVP (polyvinylpyrrolidone) coated ZnS QDS has been developed. The optical properties and morphology for the as-synthesized ZnS nanoparticles were characterized by UV-Vis absorption spectroscopies and transmission electron microscopy (TEM). The results show that PVP could act as a better stabilizer for the formation of ZnS nanoparticles in N, N-dimethylformamide. The obtained ZnS nanoparticles have spherical morphology and a narrow size distribution. ZnS nanoparticles could give an apparent extionic absorption peaks and quantum confinement effects.

Abstract: In order to improve the water flux of PVDF hollow-fiber membrane, acrylic acid (AA) was grafted onto PVDF membrane matrix through electron beam irradiation in isopropanol/water aqueous solution. The grafting conditions were optimized and the effects of grafting parameters were investigated. Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR) was used to characterize the chemical changes of the PVDF matrix. The morphological behaviors have been estimated using field emitting scanning electron microscopy (FESEM). The present study suggested that the grafting degree played a dominant role in the water flux of AA grafted PVDF membrane (PVDF-g-AA). The pure water flux of grafted membrane increased to 467.8 L/m2h, nearly two times than the original membrane.

Abstract: The paper mainly reviewed the optical energy gap and microhardness of Cu₃N thin films. The optical energy gap increases from 0.23 eV to 1.9 eV. The microhardness of Cu3N thin films was determined to be about 3.7-8.8 GPa.