Abstract: The effects of applied tensile stress on the microstructural stability of a third generation single crystal superalloy DD10 have been investigated under stressed and un-stressed thermal exposure at 980 °C. The results indicated that μ phase precipitated in the dendrite core after both stressed and un-stressed thermal exposure at 980 °C for 450 h. The μ phase formation, γ′ coarsening and rafting processes were promoted by the applied tensile stress. However, the precipitation of μ phase was not sensitive to the magnitude of applied tensile stress. Meanwhile, the applied tensile stress did not affect the type and morphology of the topologically close packed (TCP) phase. It is suggested that the interaction of the applied tensile stress and the misfit stress decreased the lattice misfit between μ phase and γ matrix and promoted the formation of μ phase.
Abstract: Using dodecyl benzenesulfonic acid (DBSA) as surfactant, composites of polyaniline (PANI)/activated carbon (AC) with core-shell structures were prepared by in situ emulsion polymerization in the presence of different concentrations of zinc ion. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis and Fourier-transform IR (FT-IR) spectroscopy were used to analyze morphologies and structures of the composites. Thermal stability of the composites was investigated by thermogravimetric analysis (TGA).The electrochemical properties of PANI/AC composites were studied by galvanostatic charge/discharge tests. The composites exhibited different electrochemical and thermal behavior, which was found to be a function of the concentration of zinc ion.
Abstract: The fatigue fracture and the microstructure of Al5Zn2Mg high strength aluminum alloy were observed by OM, SEM and TEM, and the low cycle fatigue properties were tested and analyzed. The results of experimentation show that the low cycle fatigue life of Al5Zn2Mg high strength aluminum alloy is 9.28×104 cycle in R=0.1, f=8Hz, and σmax=0.75σb. The tensile strength is 444MPa. The fatigue fracture is composed of the initiation zone, the propagation zone, and the sudden fracture zone, which is characteristic of a mixed-type fatigue fracture. The fatigue crack initiates in the surface of Al5Zn2Mg aluminum alloy sample, while there is no fatigue striation in fatigue crack propagation zone. The η′(MgZn2) transitional strengthening phases are precipitated in Al5Zn2Mg aluminum alloy, and mostly distributed in grain boundary. The diameter of η′ strengthening phase is fine, about is 10nm. There is none precipitated zone in width nearby the grain boundary
Abstract: Er-dispersed silicon-rich silicon oxide (SRSO:Er) films have been fabricated by pulsed laser ablation technique. After deposition, the films were annealed in Ar ambient at different temperatures for 30 min to generate SiO2 films containing Si nanocrystals (Si-nc) and Er ions. The relationship between Er photoluminescence (PL) intensity and annealing temperature was investigated by PL spectrums analysis at room temperature. Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray Spectrometer (EDS) were used to observe the samples. Experimental results show that high-density Si-nc generate when the annealing temperature increases to 1000°C, however, PL intensity of Er decreases due to Er atoms segregated out in SiO2 film and formed large particles.
Abstract: The saponification conditions for bentonite/sodium lignosulfonate graft acrylamide and maleic anhydride adsorbent composites (BLPAMA) prepared by solution polymerization were studied in detail. The results had shown that the optimum conditions of saponification were that the concentration of NaOH (CNaOH) = 1.0mol/L, the temperature (T) = 90°C and the saponification time (t) = 1.5h. And the maximum adsorption quantity of saponified BLPAMA to Pb2+ was 1.304mmol/g in the Pb2+/Cu2+ binary metal solution.
Abstract: Plasma enhanced atomic layer deposition (PEALD) method can decrease film growing temperature, and allow in-situ plasma treatment. LaAlO3 films were deposited with PEALD at 180°C. High resolution transmission electron microscopy (HRTEM) results exhibited amorphous microstructure of both films even after rapid thermal annealing (RTA) at 800°C. X-ray photoelectron spectroscopy (XPS) spectra suggested that the valence-band offset between the LaAlO3 film and the substrate was 3.3 eV. The electrical experimental results indicated that the leakage current densities were 0.10mA/cm2 and 0.03mA/cm2 respectively at a gate bias of |Vg-Vfb|=1V and the equivalent oxide thicknesses (EOT) of them were 1.2 nm and 1.4 nm, respectively. The densities of interfacial states were calculated to be 1.70×1012eV-1cm-2 and 1.09×1012eV-1cm-2, respectively.
Abstract: Deposition behavior of Al-Si particles coated on magnesium alloy by Supersonic Particles Deposition (SPD) was investigated by numerical stimulation. The results demonstrated that critical velocity for Al-Si particle to deposit successfully on ZM5 magnesium alloy was about 700m/s; At collision interface, the temperature gradient increased, effective plastic strain change suddenly and stress reduce rapidly to zero. The compression ratio of deposited particles increased. Contacting area at interface enlarged with particle initial velocity increasing. Meanwhile, experimental observation of surface and cross-section morphology of Al-Si coating on magnesium alloy exhibited that, intact particles, fragmented particles and fine particles co-existed in the coating. And the coating was formed by mechanical bonding and metallurgical bonding.
Abstract: ZnS thin films were deposited on indium–tin-oxide (ITO) coated glass substrates by a chemical bath deposition method. Then the ZnS/ITO slides were immersed in the solution containing 6 mM phosphate buffer solution (pH 7.4), sodium polyacrylate (0.01% w/w), and 0.24 mM AgNO3 at 37°C for 3 h to growth Ag2S films on the surface of ZnS/ITO slides. The absorption band of Ag2S/ZnS/ITO slide displays a considerably blue-shifted. The X-ray diffraction analysis demonstrated the presence of acanthite Ag2S on the surface of ZnS/ITO slides, which is consistent with the cyclic voltammetic data.
Abstract: The Ti/PbO2 electrode doped with Pr2O3 was prepared by the electrodeposition method. The X-ray diffraction (XRD) analyses indicated the crystal particles size of Ti/PbO2/Pr2O3 electrode was diminished due to the incorporation of Pr2O3 into the film of PbO2. The scanning electronic microscopy (SEM) revealed that Ti/PbO2/Pr2O3 electrode had smaller particles and larger active surface. The measurement of cyclic voltammograms (CV) revealed Ti/PbO2/Pr2O3 electrode had a better electrochemical properties comparing to Ti/PbO2 electrode. The bulk electrolysis demonstrated that the Ti/PbO2/Pr2O3 electrode presented excellent electrocatalytic performance for degradation methylene blue.