Advanced Materials Research Vols. 399-401

Abstract: The high temperature oxidation and microstructure evolution of 55%Al-Zn-Si coated sheets were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). After oxidation, the coatings consisted of three phases including ZnO, Fe₂Al₅, and FeAl from topcoat to the substrate. The different diffusion rate of Fe and Al result in forming voids at the interface of intermetallic layer and the substrate. A good agreement has been reached between the experimental data and the calculation from Chou diffusion model, which has a good predicted function. Moreover, the characteristic oxidation time and the apparent activation energy were obtained.

Abstract: In this study, brushite (CaHPO₄·2H₂O) has been coated on a stainless steel substrate using dip-coating technique. This technique offers uniform and crack-free film over entire surface of the substrate and easy to perform. Layer of brushite coated surround the stainless steel is very much affected by the parameters used namely concentration of the coating solution, speed of coating, stirring time etc. Results show that a smooth thin film is obtained when 1.5M of brushite solution is used and stirred at 50 °C for 2 hours. The optimum withdrawal rate used was 1.5 mm s^-1. Thickness of the coating obtained was around 51.37 µm which would enable the apatite to growth.

Abstract: The hybrid Ni₂Al₃/Ni coating was formed on creep resistant ferritic steels by firstly nickel electroplating and then partially aluminising the Ni layer at 650 °C by pack cementation process using powder mixtures of Al, AlCl₃ and Al₂O₃. The effect of pack Al content (W) on growth kinetics of the outer Ni₂Al₃ layer of the coating was investigated by varying it from 2 to 10 wt% whilst keeping the pack AlCl₃ content constant at 2 wt% and aluminising conditions at 650°C/4h. It was revealed that, once W was above a minimum level, the growth of the outer Ni₂Al₃ layer thickness depended linearly on W^1/2. The possible reasons for such growth kinetics were discussed.

Abstract: This topic in the reaction temperature, reaction time for 5 °C for 7 hours, aniline and ammonium persulfate mole ratio of 1:1 conditions, main research on synthesis of concentration of reactant polyaniline performance, yield, the influence of electric conductivity. By ir, conductivity meter, scanning electron microscope (sem) analysis of samples, and the results show that when the yankees salicylic acid concentration sulfonylureas 0.15-0.25 mol/L, ammonium persulfate concentration 0.1-0.2 mol/L got when the production rate is higher, anticorrosive performance is good polyaniline coatings.

Abstract: Based on the interaction mechanism of the plasma and the magnetic field, this paper has proposed the deposition process of coupled magnetic field to enhance the arc ion plating. Meanwhile, it has also analyzed the distribution, the polarity and the configuration of coupled magnetic field combining with the finite element simulation. The influence of coupled magnetic field on the distribution, the ionization rate, the surface quality of film and the deposition rate of arc ion plating has been also systematically discussed in this paper. What’s more, the reduction mechanism of coupled magnetic field for the marco-particles on film surface has been also proposed. The studies have shown that the DC coupled magnetic field can not only improve the focusing properties and the transmission uniformity of plasma, but also enhance the collision between ions and improve the ionization rate of plasma and the excitation illumination intensity of ions as well as improve the ion density. With the increase of the strength of DC coupled magnetic field, the number and the size of marco-particles on film surface have been greatly reduced and the deposition rate of film has been exponentially increased. The plasma has been gradually focalized and diverged under the influence of pulsation coupled magnetic field and formed the plasma with a dynamic distribution, which has enhanced the interaction between the plasma and the marco-particles as well as further purified the marco-particles.

Abstract: In this paper, the tribological behaviors of polyimide bonded PTFE solid lubricating film and polyimide bonded MoS2 solid lubricating film under dry sliding and under lubrication of kerosene oil, diesel fuel, paraffin liquid and lubrication oil were investigated by using a ring-on-block wear tester. The results show that the anti-friction and wear-resistance properties of both lubricating films are greatly improved under oil lubrication conditions as compared with the dry friction condition; the friction coefficients of both lubricating films under different oil lubrications keep steady-state value with 0.08; but both lubricating films under different oil lubrications reveal the different wear-resistance properties, such as the best wear-resistance properties under diesel fuel, followed by paraffin liquid, lubrication oil and kerosene oil; the differences in the wear-resistance properties of the lubricating films under different lubrication conditions are mainly ascribed to the influence of the oil’s characteristics, especially boiling point and viscosity.

Abstract: W-Mo-Dy and W-Mo permeation were carried out on the 20 steel by plasma surface metallurgy technology. The microstructure, cross-section morphology ，distribution of alloy element and phase structure of diffusion layer were tested and observed. The results showed that: thickness of alloy layer was 128μm, 108μm, there is a dividing line between the diffusion layer and the substrate, indicating that the permeation process follow with reaction-diffusion phenomena; Compared with W-Mo diffusion layer，the grain size of W-Mo-Dy diffusion layer were fine grain；The basic phase composition of W-Mo-Dy diffusion layer were solid solution of (W, Mo, Dy) in Fe, Dy₂O₃ and a small quantity of Dy Fe₁₀Mo₂; The basic phase composition of W-Mo diffusion layer was solid solution of (W, Mo) in Fe.The surface alloy contents of W-Mo-Dy diffusion layer were 4.81%, 9.99%, 4.4% (wt%), which of W-Mo diffusion layer were 3.04%, 7.68% (wt%);Heavy rare earth （Dy）has a significant penetration and improved the organizations of diffusion layer.

Abstract: A feature-based volume decomposition algorithm for robotic weld deposition-based rapid prototyping has been proposed to eliminate or reduce the use of support structure which decreases the building efficient. The algorithm decomposes the model volume into shapeable feature volume and un-shapeable feature volume firstly, according to the slope angle is greater or smaller than the critical slope angle. Un-shapeable feature volume is decomposed further into sub-volume until each sub-volume to be shapeable without support structure. Each feature volume or sub-volume may be assigned with different building orientation and building sequence in the process planning process. The model volume of a classical part was decomposed by this method to validate this method’s ability of eliminating the use of support structure.

Abstract: MIG welding and laser-MIG hybrid welding have been widely used to joint aluminum alloy in recent years. Residual stress and heat cycling of MIG welding and laser-MIG hybrid welding are analyzed by SYSWELD software. The results show that the peak values of the stress in hybrid welding is 30~50% less than the results in the MIG welded joints.

Abstract: This paper summarizes the test method of ice-phobic coating adhesion strength and the progress in coating material. Ice adhesion strength of several commercial ice-phobic coatings were tested for Pratt & Whitney, and result indicated that reformative silicone R-2180 show significantly improved reduction in ice adhesion when compared to several different commercially available silicone-based ice-phobic coatings. It would be valuable in future studies to measure the surface energies of the several materials tested to determine any correlation between the ice adhesion and surface energy of the coating.