Abstract: Short-cut grass and starch were selected as raw materials to prepare environmentally friendly composite by hot-pressing method. Results indicated that short-cut grass and starch were easily mixed uniformly by water medium and adapt to hot-pressing process. Hot-pressing time and hot-pressing temperature influenced the performances of composites. The strength and elongation first increase and then decrease with the increase of two processing factors. Tensile strength and strength at fracture reach 2.3 MPa and 1.2 MPa respectively when hot-pressing was performed at 140 °C for 10 min. The tensile strength is always higher than strength at tensile fracture and the elongation at fracture is always higher than that at maximum force. This indicates that the fracture of composite is ductile fracture. The hardness of composite is uneven. Long hot-pressing time resulted in not too obvious decrease of hardness.
Abstract: Al ion implantation of AZ31 magnesium alloy is carried out with an ion implantation dose of 1×1017 ions/cm2 at room temperature and at elevated temperature of about 200°C. ß-Mg17Al12 precipitate is observed on the ion implanted sample at elevated temperature by X-ray diffraction (XRD). Potentiodynamic polarization curves indicated that the corrosion potential and pitting corrosion breakdown potential for the samples implanted at elevated temperature are 330 and 480 mV higher than those of the unimplanted sample, respectively. The ß-phase precipitate is beneficial to the improvement in corrosion resistance of magnesium alloy. In addition, Al enrichment on the implanted surface also contributes to the improved corrosion resistance.
Abstract: Conversion coatings on cast AZ91D magnesium alloy were prepared in the manganese dihydro phosphate baths. The corrosion behavior of the coated and uncoated alloys has been investigated by polarization curve methods. The morphology and composition of coated surfaces were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX ) as well as X-ray photoelectron spectroscopy (XPS) techniques. It is found that the conversion coating surface characterized by crystal particle and was composed of Mn3(PO4)2. Electrochemical investigation results indicated that the phosphate conversion coating could enhance the corrosion potential in great extent of about 1300mV compared with Mg alloy substrate.
Abstract: As printing technology advances, environmentally friendly consumable printing materials have been explored. Water-based ink has become a new research hotspot due to its printability and environmental friendliness. Resin is an important part of water-based ink which functions as the carrier of the pigments. Its performance directly affects the printability of the ink. In order to obtain optimal ink formulation, different resins were applied and tested. This paper emphatically analyzes and discusses: (a) different resins and its performance in water-based covering ink; (b) cultivate an evaluation and rating system of resins applied. The water-based ink does not contain volatile organic compounds (VOC), which makes it to the benefit of environment protection and sustainable development.
Abstract: The hydrothermal-prepared carbon-doped titanium dioxide/graphene nanocomposite material possessed excellent photocatalytic property after annealling in hydrogen (H-C-TiO2/G). The photocatalytic activity toward decomposing gaseous formaldehyde for H-C-TiO2/G is better than that of C-TiO2 and H-C-TiO2. The microstructure of as-prepared samples was investigated by TEM, Raman spectra and XPS spectra. It is believed that the enhancement of photocatalytic activity is mainly ascribed to the synergistic effect between surface defects and Ti-C bond.
Abstract: By way of chemical marinate method, carrying out rare earth lanthanum to corrosion protect galvanized steel. The process of rare earth lanthanum conversion coating for galvanized steel was studied by using orthogonal experiment to get the optimized passivation parameters when the concentration of La (NO3) is 30g/L, H2O2 is 20ml/L, pH=4 and was passivated at 40°C for 30s. The corrosion resistance was examined by weight loss tests, neutral salt spray tests (NSS) and electrochemical impedance spectroscopy (EIS). The results showed that the corrosion impedance of the pretreated sample was significantly improved, the corrosion rate was decreased by one order of magnitude, and the anti-white rust time was 54h.
Abstract: In order to promote the comprehensive utilization of salt lake brine resources, magnesium carbonate tri-hydrate (MgCO3·3H2O) was synthetized by low-temperature hydrothermal technique using purified MgCl2-rich brine and ammonium hydrogen carbonate solution as raw materials, the orthogonal experimental as method. The morphology could be tuned by changing the operating parameters. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the structures and morphologies of the products. The results show that the optimum conditions are as follows : reaction temperature is 40-50°C, n (Mg2+):n (HCO3-)=1:2.2, pH value is 8.8-9.0, stirring speed is 130 r/min, aging time is 3h, reaction time is 70 min. Magnesium carbonate tri-hydrate synthetized is one-dimensional acicular with good settling performance. Average aspect ratio could up to 29.60.
Abstract: The corrosion tests of Cr, Fe and Ni of Hastelloy C-276 were studied at high temperature and pressure with different aggressive components. The results were investigated by means of graphite furnace atomic absorption spectrophotometer (AAS). The Cr forms stable oxide and NiO is unstable. There is a synergistic effect between salt and oxygen leading to a severe loss of metals. The PO43- can improve the resistance to corrosion for Hastelloy C-276 due to the low-solubility phosphates. The colors of effluences can better support the changed concentrations of metals. The lost metals can reveal the corrosion mechanism of Ni-based alloys.
Abstract: In order to evaluate the performance of the self-propagating high-temperature synthesis (SHS) to treat 90SrO-contained radioactive graphite in N2 atmosphere, waste forms were prepared with the self-developed SHS reactor according to the waste forms formulation designed with a solid-soluted content of 010 wt% (calibrated in mass, hereinafter the same). The waste forms were made with the exothermic reaction (3C + 4Al + 3TiO2 = 2Al2O3 + 3TiC + Q), where, 88SrO (a stable Sr isotope)-containing 88SrO was used to simulate 90SrO. And the raw materials for the waste forms were the powdery materials of graphite (C), aluminum (Al) and titanium dioxide (TiO2). Then, X-ray diffractometer (XRD) and scanning electron microscope (SEM) were used to test and analyze the phase composition and morphology of the prepared waste forms. According to the results in dealing with the treatment with the given exothermic reaction of the 90SrOcontaining radioactive graphite in N2 atmosphere, the SrO solid solubility could be up to 8 wt%. Besides, with a SrO content of 0~2 wt%, the major composition of the waste forms was including: alumina (Al2O3) in diamond scheme, titanium carbide (TiC) in cubic phase, graphite (C), anatase titanium dioxide (TiO2) and aluminum nitride (AlN) in cubic phase. Comparatively, with a SrO content of 3~8 wt%%, the major composition of the waste forms was including: alumina (Al2O3) in diamond scheme, titanium carbide (TiC) in cubic phase, graphite (C), anatase titanium dioxide (TiO2), aluminum nitride (AlN) in cubic phase and rhomboid aluminum titanate (Al2TiO5). Furthermore, diffractive peaks of unidentified phase occurred at 2θ = 7.7°, 15.6°, 19.8° and 24.1° position, whose intensities were increased with the increasing additional SrO content. The grain sizes of the prepared waste forms are mainly within 515μm, majorly exist in pieces.