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Zhong P.,Hunan Institute of Engineering | Li J.,Wuhan Research Institute of Materials Protection
Mocaxue Xuebao/Tribology | Year: 2012

The erosion wear of the polyurea elastic coating was investigated on a high-pressure water jet erosion tester. The results show that the polyurea coating had an excellent erosion resistance performance. On the basis of Bitter's erosion theory of ductile materials, the erosion model of polyurea was established. The erosion behaviors of ductile materials at different impact angle and velocity were described. And the erosion law was proposed, which held that the maximal cutting wear was at the impact angle of 30° or so and the maximal deformation wear at the impact angle closed to 90°. Source

Zhou J.-L.,University of Science and Technology Beijing | Li X.-G.,University of Science and Technology Beijing | Du C.-W.,University of Science and Technology Beijing | Pan Y.,Wuhan Research Institute of Materials Protection | And 2 more authors.
International Journal of Minerals, Metallurgy and Materials | Year: 2011

The passivation process of X80 pipeline steel in bicarbonate solutions was investigated using potentiodynamic, dynamic electrochemical impedance spectroscopy (DEIS), and Mott-Schottky measurements. The results show that the shape of polarization curves changes with HCO- 3 concentration. The critical 'passive' concentration is 0.009 mol/L HCO - 3 for X80 pipeline steel in bicarbonate solutions. No anodic current peak exists in HCO- 3 solutions when the concentration is lower than 0.009 mol/L, whereas there are one and two anodic current peaks when the HCO- 3 concentration ranges from 0.009 to 0.05 mol/L and is higher than 0.1 mol/L, respectively. DEIS measurements show that there exist active dissolution range, transition range, pre-passive range, passive layer formation range, passive range, and trans-passive range for X80 pipeline steel in the 0.1 mol/L HCO- 3 solutions. The results of DEIS measurements are in complete agreement with the potentiodynamic diagram. An equivalent circuit containing three sub-layers is used to explain the Nyquist plots in the passive range. Analyses are well made for explaining the corresponding fitted capacitance and impedance. The Mott-Schottky plots show that the passive film of X80 pipeline steel is an n-type semiconductor, and capacitance measurements are in good accordance with the results of DEIS experiment. © University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg 2011. Source

Shang H.,Wuhan Research Institute of Materials Protection
Advanced Materials Research | Year: 2011

In order to solve the problem that powder hardeners for no-bake phosphate binder sand cause powder pollution, preparation of suspended liquid hardener has been studied in this paper. Orthogonal array L 9(3 4) was selected to arrange the experiment. Under every factor and level an experiment was done, and suspension rate after four hours of the suspended liquid hardener was taken as experimental target. Results show that the addition of suspension agent and interaction between vector and suspension agent are significant factors at significance level α = 0.05. The best scheme is the one which contents 500g powder magnesia, 500g industrial alcohol vector and 20g SN suspension agent. Source

Zeng H.,Hunan University | Zeng H.,Wuhan Research Institute of Materials Protection | Wang Y.,Hunan University | Nie C.,Hunan University | And 2 more authors.
Analyst | Year: 2012

The preparation of magnetic molecularly imprinted polymers (MMIPs) which can be used for the separation and purification of rutin from Chinese medicinal plants has been proposed. By applying the improved co-precipitation method, magnetic Fe 3O 4 particles were easily prepared, followed by the modification of TEOS and functionalization with -CHCH 2. Using functionalized Fe 3O 4 particles as the magnetic cores, rutin as the template, and acrylamide as the functional monomer, MMIPs were synthesized by surface-imprinted polymerization under the protection of nitrogen gas and successive mechanical stirring at 60 °C for 24 h. Magnetic non-molecularly imprinted polymers (MNIPs) were also prepared with the same synthesis procedure as with MMIPs only without the presence of rutin. Magnetic particles were characterized by FT-IR, XRD, and TG analysis. And the selectivity of MMIPs was also investigated in detail. In addition, the performance of the MMIPs for the adsorption of rutin in the analysis of Chinese medicinal plants was assessed. The mean recoveries were 84.33% (RSD: 3.22%, n = 3) for Saururus chinensis (Lour.) Bail and 85.20% (RSD: 3.58%, n = 3) for Flos Sophorae, respectively, which showed that the prepared MMIPs with many advantages possess the value of practical application. © 2012 The Royal Society of Chemistry. Source

Huang X.,Tsinghua University | Kasem H.,Technion - Israel Institute of Technology | Shang H.F.,Wuhan Research Institute of Materials Protection | Shao T.M.,Tsinghua University | Etsion I.,Technion - Israel Institute of Technology
Wear | Year: 2012

A potential weakening effect caused by very thin hard coatings on spherical substrates is investigated experimentally. This weakening effect reduces the resistance of the coated system to onset of plasticity. Half-coated spheres are prepared using an ion beam assisted deposition system. The coated and uncoated portions of these half-coated spheres are loaded by a rigid flat into their elastic-plastic regime of deformation and then unloaded. The resulting maximum interference after loading and residual interference at the completion of unloading are measured and used in an elastic-plastic loading index model to evaluate the plasticity levels of both the uncoated and coated portions on each sphere. The experimental results validate qualitatively the potential weakening effect, which was predicted theoretically in previous publications. © 2012 Elsevier B.V. Source

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