Papers by Author: Zhen Lun Song

Abstract: Comparison tests of needles made in abroad and domestic on chemical composition, microstruture , mechanical property and so on, the main influence factors of the wear resistance were analysed. Approaches of improving the wear resistance of needles are given,such as hot process,surface treatment ,local strengthening. Combined with finite element analysis, the stress and the strain of the needle hook were analysed. Comparative results of both abroad and domestic show that the carbide in the microstructure and structural design of needles are regarded as the main influence factors of the wear resistance.

Abstract: TiN protective coating was prepared on NdFeB by DC magnetron sputtering to improve the corrosion resistance and scratch resistance of the magnetic. During deposition, the nitrogen/argon mixture gas was introduced into the chamber with the nitrogen partial pressure at 20 % and 10 % and the bias of 200 V was applied to subtract, respectively. At a lower nitrogen partial pressure of 10%, TiN coating was composed of many particles with an irregular shape. With increasing the nitrogen pressure to 20%, composing particles become small and show as the regular trihedron shape. All TiN coatings have a cubic structure. The bias makes the depositing TiN coating denser and preferential growth become no obvious. By the nitrogen partial pressure of 20 % and bias of 200 V, the dense TiN coating has best corrosion resistance and excellent wear resistance.

Abstract: Polymeric compounds are of great interest as corrosion inhibitors in acidic environment due to their inherent stability. Polymeric film is effectively used for the protection of metals partly owing to their capacity to act as a physical barrier between the metal surface and the corrosive environment. In this paper, a cation polyelectrolyte inhibitor (Quaternary Polyethyleneimine, QPEI) was prepared. The quality and inhibition efficiency of QPEI self-adsorbed films were studied by polarization curve and electrochemical impedance spectroscopy, respectively. The compositions and morphologies of the polymer film on the steel surface were examined with the aids of SEM and XPS, respectively. The results showed that QPEI could greatly retard the corrosion of iron in sulfuric acid, which was attributed mainly to the protective QPEI film formed on the surface. Meanwhile, the inhibition of QPEI could be supposed as a mixed process, in which both cathodic and anodic corrosions were simultaneously restrained. Based on the results of XPS and SEM, it could be evidenced that the QPEI can form a protective polymer layer on the metal surface by adsorption.

Abstract: NdFeB permanent magnets are highly susceptible to corrosion in various environments. A new composite coating electrodeposited on NdFeB magnets was investigated in this paper. The Ni matrix film was firstly electrodeposited on NdFeB surface from watts nickel electrolyte, and then Ni/Al2O3 composite coating was successively electrodeposited on the Ni film. The microstructures of electrodeposited Ni coating and Ni/Al2O3 composite coating were observed by scanning electron microscopy (SEM). The corrosion behavior of Ni coating and Ni/Al2O3 composite coating in 3.5wt% NaC1 solution was studied by polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that the Ni coating and Ni/Al2O3 composite coating could both provide adequate protection to NdFeB substrate. But the free corrosion potential of Ni/Al2O3 composite coating was more positive and the passivation region was more obvious when compared with Ni coating. Meantime, the capacitance loop diameter of Ni/Al2O3 composite coating was significantly larger than that of Ni coating ,which suggested that the anticorrosion resistance of Ni/Al2O3 composite coating was better than electroplated Ni coating.

Abstract: Electro-deposition Cu-In alloy can act as the precursor film to prepare CuInSe2 compound by selenating treatment. The effect of pH value on the electrodeposition potential of Cu-In alloy was investigated by electrochemical measurements in this paper. The relationship between the pH values and deposition potential was analyzed. Then uniform Cu-In alloy film was successfully prepared based on the special potential and pH.