Advanced Materials Research Vols. 239-242

Abstract: Stationary seal ring, the mainly units of mechanical seal, its anti-lacking function mostly depends on the material performances. For enhanced stationary seal ring’s thermal conductivity, self-lubrication and strength, in this paper authors prepared a kind of composite material with reticular formation that is foam Ni-carbon nano tubes (Foam Ni/CNTs) as the reinforced element for stationary seal ring’s resin matrix. The experiments using Fe-Co/CNTs as catalyst via chemical vapor deposition (CVD) method prepared four groups samples with different decomposition temperature and tested by SEM and Raman spectra. The result shows that the temperature at 550°C, carbon nano tube obtained better crystallization effect and the reticular structure of foam Ni also integrity. The foam Ni/CNTs presented one kind of new reinforced phase for mechanical seal material design.

Abstract: Zinc oxide (ZnO) nanocrystalline with different morphologies was successfully fabricated by solid-state reaction using aging Zn as precursor. Systematic experiments were carried out to investigate the factors that affect the morphologies of the samples. X-ray diffraction (XRD) spectrum shows that the as-prepared sample was hexagonal wurtzite structure. Scanning electron microscopy (SEM) images indicate that ZnO with different morphologies such as comb-like, tetrapod and flake structures, could be controlled by simply varying the ambient pressure, gas mixture ratio and growth temperature. The gas sensitivity properties of ZnO nanocrystalline thin films are investigated by observing the change of capacitance and conductance with a planar capacitor. It is found that the comb-like ZnO thin film sensor exhibits high sensitivity and fast response to ethanol at 150 °C.

Abstract: The electrochemical behaviors of zinc electrode containing Bi, In and Al were tested to study aluminum acting on the electrochemical performance of zinc anode using anodic polarization and tafel profiles measurement. The element distributions of IBA alloy were observed by scanning electron microscope (SEM). Our recent investigations demonstrate that the electrochemical activity of zinc alloy could be improved largely through integrating the optimization content of aluminum into zinc alloy. The SEM images show that there are obvious differences in the element distributions of surface, subsurface or bulk phase, especially, the segregation of Al in subsurface or bulk. The electrochemical behaviors of IBA alloy are related to its physical properties.

Abstract: Variation law of combustion performance of glass fiber reinforced epoxy composites under different heat fluxes was studied. Final result shows that the time of epoxy resin composite shortened when increased the heat flux, and the theoretical minimum ignition heat flux obtained by curve fitting of experiment data is 2.1638kW/m²; multiply heat flux increased the heat release rate and complicate the stratified combustion of materials, which making the heat release rate curves more complicated. What is more，multiply the heat flux caused incomplete combustion of materials and leaded greater smoke production rate. The residual quality decreased as increased heat flux, however when the heat flux beyond 50kW/m², the residual quality no longer decreased, which suggested that the heat flux used to study these materials should not be more than 50kW/m². To sum up the above combustion parameters ,we could know that the safety performance of this epoxy composite was medium level, in order to improve its security level further, smoke suppression should be handled.

Abstract: A novel compound gypsum waterproof agent made of emulsified stearic acid, alunite and naphthalene were studied, which could modify the waterproof performance of gypsum materials in microstructures. The experiment results showed that the water-absorption rate of gypsum materials can be reduced to 3.73% and that the compressive strength reserve rate was 84.71% after 24h. The waterproof mechanic of alunite is the hydration materials of alunite can fill the materials’ porosities, which can no longer be filled with water, so it reduces the water absorption and improves the strength; The waterproof mechanic of stearic acid emulsion is that it improves the gypsum material surface performance and makes the surface performance convent from hydrophilic performance to hydrophobic performance.

Abstract: As a good insulator, the surface resistance of polyurethane is large and the conductivity is poor, which made it easy to produce static electricity and cause explosion, fire and other incidents. A coating antistatic agent was prepared through designing and modifying which can significantly improve the antistatic properties of polyurethane seal materials for coal mine, without affecting the operational performance. Especially, it not only can meet the requirements of antistatic performance for coal mines, but also environmental friendly.

Abstract: HPAM with MW of 3×10⁶ was found suitable to simulate the composition of the formation water in Daqing Oilfield. PAC, CPAM and ZTP were used for treating the produced water from polymer flooding in Daqing Oilfield. The micro structures of the suspended materials in produced water were observed with particle imager and SEM. The results show that ZTP removed HPAM efficiently, and that both PAC and CPAM produced many aggregates.

Abstract: The luminescent properties of Eu²⁺, Mn²⁺co-doped Ca₂SiO₃Cl₂ phosphors synthesized by the sol-gel method were investigated. The crystal structure, pattern and luminescence properties were characterized by the X-ray diffraction (XRD), scanning electron microscope (SEM), and photoluminescence (PL) testing. The result showed that pure Ca₂SiO₃Cl₂ was prepared at 570°C for 8h in the active carbon weak reducing atmosphere. The phosphor particles showed Eu²⁺ by the excitation spectrum located at 365nm found that spectra with an emission peak located at a 446nm and the other emission spectrum was dominated by the green peak located at 497nm. Due to the Eu²⁺ center transfer energy to the Mn²⁺ center that there be an emission spectrum peak located at 580nm. Three of emission spectrum peaks stacking to white light.

Abstract: Nano-diamond/Ni and Ni coatings were prepared by brush plating. SEM and XRD methods were applied to investigate the morphology, nano-crystalline structure and grain size of the coatings. The results show that the grain size of the brush coatings all is in nanometer scale. The surface morphology of the composite brush coatings is a finer and denser cauliflower-like structure. Meanwhile the reasons of formation nano-crystalline structure are the high over-potential, the discontinuous grain growth resulted from the reciprocating motion and friction between the plating pen and the work piece, the heterogeneous nucleation of the nano-diamond, and the point discharge effect. The nano-diamond as the second phases decreases the grain size of the coating and consequently increase the strength of the composite coatings largely.

Abstract: The density and anodic potentiodynamic polarization (PDP) in different diluted acidic sulphate solution of the aluminum electrodeposion coating on Q235 steel substrate, obtained in the molten salt of AlCl₃,NaCl and KCl and treated by diffusion treatment, have been investigated. The results indicated that with the increase of temperature of diffusion treatment, the dencity of the coatings increases first, then reduces little. At 500°C, the dencity is biggest, 2.76g/cm³, which is almost equal to that of compact pure aluminum. As-received coating displays a current oscillation behavior on the anodic potentiodynamic polarization curves in different diluted acidic sulphate solution . And with the increase of diffusion temperature, the current oscillation behaviors donated by the current oscillation domains in solution of 180g/L H₂SO₄ gradually disappeared. When the temperature is up to 500°C and 700°C, no current oscillation phenomena can be observed. Based on these phenomena, a mode between the porosity of the coating, which was affected by the temperature of diffusion treatment, and current oscillation behaviors was roughly established.