Liu R.,Baosteel |
Wei X.,Shanghai University |
Tao D.,Shanghai University |
Zhao Y.,Wuhan Research Institute of Materials Protection
Tribology International | Year: 2010
Surface-modified mixed rare earth nanoparticles are prepared and their tribological performances as lubrication additives are evaluated using a four-ball friction and wear tester. The analytical results show that the average size of the particles is less than 30 nm and they exhibit excellent anti-wear, load-carrying and good friction-reducing capacities in base stock. Auger electron spectroscopy (AES) and X-ray photoelectron spectrometry (XPS) are performed to investigate their tribochemical mechanism and the results indicate that there is a boundary film composed with ferrous oxides, organic acid, rare earth oxides and complex of rare earth metals formed on the rubbed surface. The high concentration of ferrous oxides in the friction surface, which attributes to the oxidation catalysis of nano rare earth particles during the friction process, may be the main reason that leads to their excellent tribological properties. © 2009 Elsevier Ltd. All rights reserved.
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°.
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.
Yuan C.Q.,Wuhan University of Technology |
Li J.,Wuhan University of Technology |
Dong C.L.,Wuhan University of Technology |
Li J.,Wuhan Research Institute of Materials Protection |
Yan X.P.,Wuhan University of Technology
Wear | Year: 2011
Rubbing pairs of ceramics and stainless steel are widely used under the hydrogen peroxide (H2O2) strong oxidizing environment. It is crucial to study the wear behavior and failure modes of the rubbing pairs. The tribological properties of three types of ceramics (ZrO2, Al2O3, Si3N4 ceramics) and 1Cr18Ni9Ti stainless steel rubbing pairs were investigated using a tribo-tester under different concentrations of H2O2 solution. The comparative analysis of the friction coefficients, wear volumes, worn surface topographies and corrosion potentials was conducted under different concentrations of H2O2 solutions. There were significant differences in the tribological and electrochemical properties of the rubbing pairs in different H2O2 solutions. As a whole, the rubbing pairs of Si3N4 ceramics/1Cr18Ni9Ti stainless steel have the best tribological properties in H2O2 solutions. It is believed that the knowledge obtained in this study will provide a guide for the selection of the rubbing pairs in the H2O2 solutions. © 2011 Elsevier B.V.
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.
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.
Xiao Y.,Wuhan Naval University of Engineering |
Jiang X.,Wuhan Research Institute of Materials Protection |
Xiao Y.,Wuhan Research Institute of Materials Protection |
Ma L.,Wuhan Naval University of Engineering
Procedia Engineering | Year: 2012
In the aluminium content on corrosion resistance of zinc - aluminum alloy coating effects research foundation, through our country typical natural atmosphere and seawater, freshwater environment exposure test and laboratory conditions of neutral salt spray corrosion test and electrochemical methods ,study on thermal spraying Zn, Al and Zn- Al15 metallic coatings in different natural environment protection performance of steel. Study found that compared with thermal spraying Zn, Al coating, Zn-Al15 alloy coating on the steel has the same excellent electrochemical cathode protection features of thermal spraying Zn coating, but also has high corrosion resistance characteristics of thermal sprayed Al coating. To further improve the protective properties of thermal spray coatings, on the basis of above, composite protective technology research which is about thermal spray metal coating was carried out. Exposure corrosion tests in Qingdao seawater and Wuhan Yangtze freshwater environment for two years showed that the composite system of thermal spray metal coating which is formed after its closed / coating treatment, is superior to single metal thermal spraying in protection performance. At present, thermal spray Zn-15Al alloy coating and sealing / coating composite protective system has been used in the national water, bridges and other key infrastructure projects. © 2011 Published by Elsevier Ltd.
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.
Gao X.,Wuhan Polytechnic University |
Hua M.,City University of Hong Kong |
Li J.,Wuhan Research Institute of Materials Protection |
Gao W.,Wuhan Research Institute of Materials Protection
Materials and Design | Year: 2010
A pin-disk tester and a scanning electron microscope (SEM) were used to study the dry tribological properties of a new kind of ultra-high molecular weight polyethylene (UHMWPE) modified with a Schiff base copper complex and a glycerol-polyethylene microencapsule that was paired with GCr15 steel. Results, using a relatively high sliding speed, showed the excellent dry tribological characteristics of the modified UHMWPE/steel rubbing pair compared with the pure UHMWPE/steel rubbing pair. The tribological behavior of the former could be explained by the mechanism of self-selective transfer while that of the latter could be explained by the normal theory of plastic tribology. Results suggested that the modified UHMWPE could be used in dry friction conditions with a relatively high sliding velocity, in situations where the traditional plastic failed to operate correctly. © 2009.
Shang H.-F.,Wuhan Research Institute of Materials Protection
Zhuzao/Foundry | Year: 2010
In this paper, MgO and Fe 2O 3 were used to make the compound hardener for phosphate bonded sand, and the properties of no-bake phosphate bonded sand were studied. Results show that the no-bake phosphate bonded sand cured by compound hardener has good hardening strength, long service life, good hardening characteristics, and good collapsibility. When the compound hardener contains 15% Fe 2O 3, the hardening strength of the sand can reach 0.66 MPa, and the value of t k/t t is 0.36.