Papers by Author: Bin Shi Xu

Abstract: This paper reports on a new clad technology that is protective coating cladding. The method is that the Ni60 alloy was prepared on 0.45%C steel and high temperature powder paste brushed on the outside. Then the sample after being dried was heated in the high temperature resistance electric furnace. The Ni60 alloy powder on the substrate steel was melted at the appropriate temperature, and a uniform, adherent and non-dilution clad coating was obtained after optimizing the cladding parameters. The coating microstructures, compositions and microhardness were analyzed by OPM, XRD, EPMA, and microhardness testing. The experimental results show that the protective coating cladding is an efficient and economic method in cladding technologies

Abstract: To remanufacture hard chromium-plated workpiece, nano-Al₂O₃/Ni-Co composite coatings and Ni-Co alloy coatings are developed using electric brush plating technology. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) are used to analyze the surface morphology, phase structure and wear properties of coatings. The surface morphology of nano-composite coating is more compact. The nano-particles are well-distributed in the coating and bounded tightly with the substrate. The hardness of composite coating is HV1027, increased approximately 38% compared with Ni-Co alloy coating, overtaking the hard chrome plating. The results of sliding wear test shows that the nano-composite coating reduces friction coefficient, increases wear resistance significantly and exceeds the chromium plating.

Abstract: The aim of this paper is to address the accelerated fatigue life under rolling contact condition of coatings. The NiCr-Cr₃C₂ ceramic-metal and Ni-Al alloy were deposited on steel substrate as topcoating and undercoating using supersonic plasma spraying technique, respectively. Accelerated fatigue life tests were conducted using a ball-on-disc tester. The life of coatings was evaluated by Weibull distribution plots and the accelerated fatigue life model was established. The results showed that the coupling relationship between the load and failure life of coatings could be obtained using this model. Accelerated life test for fatigue of coatings could improve the experimental efficiency.

Abstract: Nickel coating was prepared on surface of Epoxy Resin plate by electroless plating process. Surface and section morphologies of the coatings were observed by scanning electron microscopy (SEM) and metallographic optic microscopy. Electromagnetic shielding effectiveness was evaluated via flanged coaxial electromagnetic shielding effectiveness tester. The results showed that the surface of the nickel coating prepared by electroless plating process was smooth, and its structure was fine and compact. The electroless deposition rate of the nickel coating reached at 12μm/h. In the frequency range of 300 kHz to 100MHz the electromagnetic shielding effectiveness of the nickel coating was above 60dB, and in the frequency range of 100MHz to 1.5GHz the electromagnetic shielding effectiveness of the nickel coating was above 44dB.

Abstract: Ultrafine fibers were electrospun from polyacrylonitrile (PAN)/N,N-dimethyl formamide (DMF) solution as a precursor of carbon nanofibers. The effects of solution concentration, applied voltage and flow rate on preparation and morphologies of electrospun PAN fibers were investigated. Morphologies of the green fibers, stabilized fibers and carbonized fibers were compared by scanning electron microscope (SEM). The diameter of PAN nanofibers is about 450nm and the distribution of diameter is well-proportioned. Characterization of the elements changes of fibers were performed by X-ray photoelectron spectroscopy (XPS).

Abstract: With considering the Marangoni convection in the molten pool on plasma direct metal forming process, a finite element model posed to describe and reflect the flow in the molten pool. Results of temperature distribution modeling prepared by plasma direct metal forming process of metal powders in an Ar environment were numerically obtained and compared with experimental data. Powders of Fe314 and base plates of R235 steel were taken as sample materials. In the experiment a multi-stream nozzle capable of delivering metal powder coaxially with the plasma arc was used. The model revealed that the velosity of the front part of the pool is a little slower than aft part. Marangoni convection reinforced the convection and enhanced the heat transfer. Profile of the model is the same as the experimental data. This allows us to conclude that the model can be applied for preselecting the process parameters. Keywords: plasma, rapid forming, temperature field, Marangoni convection.

Abstract: An acrylate emulsion was modified by vinyltriethoxy silane (VTES, trade name A-151) to synthesize the acrylosilane emulsion with high properties. The effect of the amount of A-151 on the properties pf the emulsion was investigated. It found that adding 6 % of A-151, the fraction extensibility of the emulsion film could be increased to 530 % and its water absorption was reduced to 4.2 % while adding 10 % of A-151. On the other side, the particle size and distribution of the emulsion were analyzed by Scanning Electron Microscopy (SEM) and Malvern Particle Size Analyzer (PSA) respectively. The measuring results showed that the particle diameter of the modified emulsion could be between 100 and 700 nanometers, and the properties of the emulsion could be apparently improved by adding A-151 into the system of emulsion polymerization.

Abstract: The quality of remanufacturing products, which is always restricting the development of remanufacturing industry, is one of sixty-four-dollar questions. By detecting the cores, process control in remanufacturing production and certificating remanufacturing products, quality control of remanufacturing products is studied. Because of cores different in original states, remanufacturing is in low-volume on the whole. Based on Bayesian posterior analysis, the paper improves the control chart and uses the previous data to monitor the production process. Finally, some advances are given to remanufacturing product certification.

Abstract: The corrosion behavior of Al-RE coating in copper accelerated acetic acid salt spray test (CASS) was studied by electrochemical impedance spectroscopy (EIS). Typical EIS spectral changes were clearly observed during the CASS process. The EIS was shown to be a very useful tool for studying corrosion resistance mechanism. Scanning electron microscope and X-ray energy dispersive spectroscopy were used to analyze the microstructure of Al-RE coatings before and after CASS test. The results revealed that the corrosion behavior of Al-RE coating could be divided into two different stages. In the first stage of CASS, there were two capacitive impedance semicircles in the complex plane plots. The high frequency semicircle responded to barrier layer, the low frequency semicircle responded to the electrochemical reaction of Al-RE coating. In the second stage of CASS, porous layer began to influence the electrochemical behavior.

Abstract: In this paper, we adopted a novel method, namely, magnetron sputtering + low temperature ion sulfurizing composite technology to prepare synthetic MoS2/FeS multilayer film. The obtained film has a quite smooth surface with plenty of spherical particles. The friction tests were carried out on a ball-on-disc tester under dry condition. During the whole test, the friction coefficient of the MoS2/FeS multilayer film was always lower than that of the original 1045 steel and FeS film. In addition, the wear scar depth of the MoS2/FeS multilayer film was also low. It is undoubtedly that the synthetic MoS2/FeS multilayer film possesses excellent friction-reducing and wear-resisting behaviors.