Advanced Materials Research Vols. 399-401

Abstract: Highly selective molecularly imprinted layer-coated silica nanoparticles for paclitaxel were synthesized by molecular imprinting technique with a sol–gel process on the supporter of silica nanoparticles. The morphology of the obtained polymers was characterized by scanning electron microscopy (SEM). The binding properties of the imprinted polymers were evaluated through the equilibrium rebinding experiments. Scatchard analysis revealed that two classes of binding sites were formed in the imprinted polymers with equilibrium dissociation constants of 0.0509 g•L-¹ and 0.0094 g•L^-1, respectively. Paclitaxel and its analogue were employed for selectivity tests. The results indicated that the imprinted polymers exhibited good selectivity and specificity toward paclitaxel.

Abstract: In this study, TiN coatings were deposited on 201 stainless steel by multi-arc ion plating (MAIP). The effect of negative bias voltage on the surface microstructure, hardness, phase structure and the corrosion resistance of the coatings were investigated by SEM, hardness instrument, XRD and electrochemical measurement. The number and size of droplets decreased when the negative bias voltage increased from -100 V to -300 V. But when the substrate bias increased to a certain value, there were some pits appeared. The hardness increased at first and decreased later with the increasing of the negative bias voltage. When the negative bias voltage was -200 V, the hardness was the highest. The intrinsic hardness of TiN film was 2195HV. In 3.5% NaCl solution, the corrosion resistance of TiN coatings samples were improved slightly compared with 201 stainless steel. In l mol/L H2SO4 solution, the corrosion resistance of -100V sample was the best, the corrosion resistance of -100V coating sample was increased 486 times compared with untreated 201 stainless steel.

Abstract: A Nb-C alloyed layer formed on TiAl by plasma Nb alloying followed by carburization was investigated. The alloyed layer was characterized using SEM, TEM, XRD and GDS. Effects of Nb alloying and the carburizing atmosphere on microstructure of Nb-C alloyed layers were analyzed. The forming mechanism of the Nb-C alloyed layer was verified using first-principle calculation. The results reveal that the Nb-C alloyed layer is composed of NbC and Nb2C. An addition of niobium in TiAl accelerates the diffusion of carbon atoms in the Nb-alloyed layer, leading to a thicker alloyed layer with higher carbon content. The carbon concentration and diffusing depth increase with methane gas. First-principle calculation shows that the forming energy of Nb-C duplex-treated TiAl is lower than those of single carburized TiAl and Nb-alloyed TiAl.

Abstract: Mercury-stannum reactive wetting behaviors were studied by the sessile drop technique at room temperature, and wetting surface and interface were also studied respectively by methods of field emission scanning electron microscope (FESEM) and XRD. It showed that mercury droplets wetted completely on the stannum substrate, on whose surface up-and-down cellular structures were generated, and two metallographic microstructures of intermetallic compounds, Hg_0.1Sn_0.9 and Hg_1.25Sn_8.75, were produced in wetting interface.

Abstract: The lamellar nanostructured yttrium films on α-Al₂O₃ substrates were successfully synthesized by electroless deposition using the lyotropic liquid crystalline templating strategy. The reaction of hydrazine hydrate and Y³⁺ dissolved within the aqueous domains of the lyotropic liquid crystalline phase produced the nanostructured yttrium films. The low-angle X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM) indicated that the as-resulted films possessed lamellar regular array of nanochannels with periodicity of 6 nm. With well-defined nanochannels and higher surface areas, the nanostructured films may find applications in the field of electronic materials.

Abstract: Removed due to author's request.

Abstract: Fe + Si coatings were prepared by iron deposition from a bath containing a suspension of silicon powders. These coatings were obtained at galvanostatic conditions, at the current density of jdep=−0.020 A cm−2 and at the temperature of 338 K. For determination of the influence of phase composition and surface morphology of these coatings on changes in the corrosion resistance, these coatings were modified in an argon atmosphere by thermal treatment at 873 K for 2h. A scanning electron microscope was used for surface morphology characterization of the coatings. The chemical composition of the coatings was determined by EDS and phase composition investigations were conducted by X-ray diffraction. It was found that the as-deposited coatings consist of a two-phase structure, i.e., iron and silicon. The phase composition for the Fe + Si coatings after thermal treatment is markedly different. The main peaks corresponding to Fe and Si coexist with the new phases: FeSi. Electrochemical corrosion resistance investigations were carried out in 3.5wt% NaCl, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. On the basis of these investigations it was found that the Fe + Si coatings after thermal treatment are more corrosion resistant in 3.5wt% NaCl solution than the as-deposited coatings. The reasons for this are a reduction in the amount of free iron and silicon, the presence of new phases (in particular silicides), and a decrease of the active surface area of the coatings after thermal treatment.

Abstract: In this paper, the semiconducting behavior of No.20 carbon steel coated with different polymer coating in 5‰ sulfuric acid solution was studied by utilizing potential-capacitance and Mott-Schottky analysis. It showed that in the same testing condition, the phenol aldehyde resin and epoxy resin showed n-type semiconducting behavior in 5‰ sulfuric acid, whereas for the alkyd resin, it showed p-type semiconducting behavior in 5‰ sulfuric acid solution. It was suggested that the space charge layer of the polymer coating in 5‰ sulfuric acid solution might be asymmetry. It was suggested that at the early stage of immersion, the polymer coating behaved as an insulator, with increasing immersion time, the coating transferred to P-type semiconductor, then to N-type semiconductor.

Abstract: Low cycle fatigue behavior of spray formed superalloy GH738 at 650°C has been investigated under fully reversed total strain-controlled mode. When strain amplitude (Δε_t/2) is between 0.32% and 0.4%, cyclic stress response is stable under fully reversed constant total strain amplitude. The stabilized hysteresis loops narrowing sharply to a straight line indicates that the alloy exhibits typical elastic strain. The crack initiates single site from the surface. When strain amplitude is between 0.6% and 1.0%, cyclic hardening is observed until fracture. The tendency for hardening is found to increase with strain amplitude. The hyperesis loops expand gradually, which indicates that plastic deformation happens during cyclic deformation process. The crack initiates multi-sites from the surface. The cyclic strain-stress relationship of spray formed GH738 at 650°C can be illustrated by Δσ/2 =2017(Δε_p/2)0.1489.The total strain-life function can expressed by Δε_t/2=0.0071(2N_f) _-0.0781 +0.0647(2N_f) ) _-0.4914.

Abstract: Joining behavior of long glass fiber reinforced polypropylene (LFT) by three types of adhesive was investigated. Single-lap shear testing was used to evaluate the performance of adhesively bonded structures. The two-part acrylic adhesive DP8005 was determined to be the best among the three adhesive candidates, which was attributed to its low surface energy. The stress distribution in the adhesive layer of the single lap joint was modeled by static elastic analysis using ANSYS software. The shear and peel stresses peaked at the edges of the adhesive layer.