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Wei Z.F.,Dalian University of Technology | Zheng X.H.,Dalian Light Industry School | Yu Z.Y.,SAIC
Advanced Materials Research | Year: 2013

The paper mainly focused on burr removal of the miniature hole drilled on aluminum plate by electrochemical machining. A mathematical model for the electrochemical deburring of miniature holes (M-ECD) was established based on the finite element analysis to the current density distribution. Both theoretical analysis and experimental study were held on the effects of many factors to the deburring results. The results proved that predictions based on our mathematical model were agreed with the experimental data comparatively. © (2013) Trans Tech Publications, Switzerland.

Zheng X.H.,Dalian Light Industry School | Wei Z.F.,Dalian University of Technology | Huang S.,Dalian University of Technology
Advanced Materials Research | Year: 2013

The pulse electrochemical finishing (PECF) of GCr15 bearing steel was studied. The effect of the main processing parameters, such as electrolyte concentration, inter-electrode gap, current density, pulse parameters, and processing temperature, on the processed surface quality was discussed. The results indicate that PECF has a good effect on GCr15 bearing steel and has a good application prospect on the finishing of bearing raceways. © (2013) Trans Tech Publications, Switzerland.

Jia L.,Dalian Maritime University | Liang C.,Dalian Maritime University | Huang N.,Dalian Maritime University | Duan F.,Dalian Light Industry School | Wang L.,Dalian Maritime University
Materials and Manufacturing Processes | Year: 2014

Bioactive composite coatings containing hydroxyapatite on magnesium alloy AZ91D are prepared successfully by microarc oxidation (MAO) coupled with sol-gel treatment. The morphologies of the composite coatings formed by MAO treatment at 0.5 A · cm-2 current density coupled with sol-gel treatment appear to be much denser and smoother than the coatings produced at 1.0 A · cm-2. The Ca/P ratio (1.70) of the composite coatings produced at 0.5 A · cm-2 is slightly higher than the ratio of the sol prepared (1.67), due to the substitute groups in apatite lattice according to the Fourier transform infrared spectroscopy test. Moreover, electrochemical tests illustrate that the composite coatings (0.5 A · cm-2) have higher open-circuit potential, corrosion potential, and corrosion resistance than the composite coatings at 1.0 A · cm -2. Immersion tests have been performed showing an enhanced bioactivity and apatite-forming ability. Consequently, combining the MAO and sol-gel treatments provides a promising candidate for further investigation. © 2014 Copyright Taylor & Francis Group, LLC.

Wei J.,Liaoning University | Chang C.,Liaoning University | Zhang Y.,Liaoning University | Hou S.,Dalian Light Industry School | And 2 more authors.
Journal of Chemical Thermodynamics | Year: 2015

Two novel ionic liquids based on serine [Cnmim][Ser] (n = 3, 4) were prepared by the neutralization method and their structures were confirmed by 1H NMR spectroscopy and differential scanning calorimetry (DSC). The density, surface tension, and refractive index of the two ILs were measured from T = (298.15 to 338.15) K. Since these ILs [Cnmim][Ser] (n = 3, 4) could form strong hydrogen bonds with water, small amount of water in the ILs is difficult to removed by common methods. In order to eliminate the effect of trace of water, the standard addition method (SAM) was applied to these measurements. On the basis of the experimental data, the speed of sound (μ), thermal expansion coefficient (α), molecular volume (Vm), standard entropy (S0298), entropy of surface (Sa), energy of surface (Ea), parachor (P), molar polarization (Rm), and polarization coefficient (αp) were calculated, and the relationship between each of these properties of [Cnmim][Ser] (n = 3, 4) and temperatures was discussed. According to the additivity, the average value of anionic parachor, P-(ave), was 180.81 for [Ser]-. At the same time, the surface tension of these serine ionic liquids could be estimated from their parachor and refractive index. The estimated values of the surface tension and the corresponding experimental data were almost identical. © 2015 Published by Elsevier Ltd.

Jia L.,Dalian Maritime University | Liang C.,Dalian Maritime University | Huang N.,Dalian Maritime University | Duan F.,Dalian Light Industry School | Wang L.,Zhengzhou University of Light Industry
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2015

Hydroxyapatite coatings were prepared on magnesium alloy AZ91D by pulsed electrochemical deposition. The effects of electrochemical deposition parameters such as pulsed voltage, electrochemical deposition time and electrolyte additive on the morphology, the microstructure, the composition, the coating thickness and electrochemical properties were tested. The results show that at 110 V, the coating with lower porosity, more homogeneous surface and nanometer particles can be obtained, which also has higher XRD diffraction peaks. The morphology and the microstructure of hydroxyapatite particles of the samples prepared in Ca-P electrolyte with NaNO3 and H2O2 addition at 110 V are optimized. The corrosion resistance of the prepared coating is enhanced in potentiodynamic polarization and electrochemical impedance tests. Moreover, immersion test results indicate that such a coating is beneficial to hydroxyapatite formation and enhancing the bioactivity in simulated solution. Copyright © 2015, Northwest Institute for Nonferrous Metal Research. Published by Elsevier BV. All rights reserved.

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