Advanced Materials Research Vols. 750-752

Abstract: The characterization of surface wear resistance of materials usually relies on the measurement of slight wear. There are two obvious shortcomings for weighing method. In order to improve the measurement accuracy, a more intuitive and reliable method for quantitative measurement of slight wear, interference microscope method, has be given. Higher accuracy (the order of micrometer) can be achieved using the interferometry for the measurement of slight wear. The results show that the masking processing technology can ensure that all samples for wear testing and other analysis are obtained under the same pretreatment conditions and vacuum processing conditions, speed up the commercialization of processing technology, and comparing the cross-sectional areas of wear scars is a correct way to characterize the wear resistance of different zones.

Abstract: According to analysis of operation condition and failure mechanism of converter hood, we designed a protective coating material and sprayed on the converter hood of Tianjin Iron & Steel Group Co. Ltd. by supersonic arc spraying technology, extended the working life of the converter and increased the output and benefit.

Abstract: By adding various concentrations of rare earth cerium into the acidic hypophosphite plating baths, electroless Ni-P-PTFE coatings have been successfully deposited on the surface of shaft made of mild steel. Surface morphology, microhardness and interfacial adhesion of the coatings were characterized by scanning electron microscope equipped with energy dispersive spectrometer, vicker microhardness meter and WS-92 scrape instrument, respectively. Ring-plate wear test was applied to study the friction coefficient and wear resistance of Ni-P-PTFE coating. Results revealed that Ni-P-PTFE coatings deposited with 10ppm or 20ppm cerium in the plating baths show low friction coefficient and high interfacial adhesion,leading to its perfect wear resistance. However, both the interfacial adhesion and wear resistance of the Ni-P-PTFE coatings were decreased drastically as the cerium concentration in the plating baths was exceeds 50ppm.

Abstract: On the copper substrate the DLC films is preparated by plasma elcctrodeposition in methanol aqueous solution. The plating solution composition: alcohol water proportion is 4:1, the additive KCl content is 3g/L and the AlCl3 is trace amounts. The influence of the current density and the electrode spacing to the electrode surface bubble zone thickness, uniformity and stability are discussed in the article. The film surface morphology is observed by scanning electron microscopy (SEM). The thickness of the film D=30, 350, 410 and 380 nm. The deposition rate K=150, 175, 205 and 190 nm/h. The polycrystalline structure of the film can be observed through the X-ray diffraction (XRD) pattern., the characteristic peak of the (111),(200) and (220) crystal plane are observed at 2θ= 43.9°,50.9°and75.3°. The high carbon content is observed by EDX analysis.

Abstract: Fe-Al intermetallic coating was prepared on 3Cr13 steel by hot-dip aluminizing and diffusion process. The morphology and phase of the coating were analyzed; the erosion behavior of hot-dip-aluminized 3Cr13 steel was investigated. Results showed that the thickness of the coating increased with diffusion temperature, but decreased when diffusion temperature exceeded 800°C. The Fe-Al alloy layer diffused at 900°C presented compacted microstructure, and mainly contained FeAl and a few Fe₃Al. Fe-Al intermetallic coating possessed obviously declined erosion loss compared with unaluminized 3Cr13 steel and represented typical erosion characteristics of ductile material.

Abstract: A conversion coating was obtained in the molybdate based bath on hot dip galvanized steel. The influence of the bath service life and bath component variation on the corrosion resistance of the conversion coating were investigated. Corrosion resistance of the coating was evaluated by electrochemical technique in 3.5%NaCl. It is found that the anodic branch of polarization curves presented in passivation character. Electrochemical impedance spectroscopy (EIS) results confirm that the radius of the capacity impedance for molybdate film decreased with treating area, which reveals that the bath life and bath component variation affected anti-corrosion performance of the coating remarkablely. The bath constituent was analysed by inductively coupled plasma atomic emission spectrometry (ICP), and the results show that the bath will lose the passivation ability after treating 1.16m² sample area for new prepared treating solution of 500ml. The surface morphologies of the coatings were observed using scanning electron microscopy (SEM), and the element composition of the coatings was detected using energy dispersive X-ray (EDX). The investigation results indicate that uniform and compact film is formed on the surface of the galvanized steel, and the film is composed of zinc,oxygen, phosphor and molybdenum.

Abstract: Molybdate-phosphate conversion coating was prepared by adding addition agent towards molybdenum-phosphorus compounds based bath on comercial hot dip galvanized steel. The anti-corrosion performance of the coating was evaluated by electrochemical technique in 3.5%NaCl. It is found that the anodic branch of polarization curves presented in passivation character. Electrochemical impedance spectroscopy (EIS) results indicate that the radius of the capacity impedance for molybdate-phosphate film increased distinctly with pH decrease, which validate the excellent anti-corrosion performance of the film. The surface morphologies were observed using scanning electron microscopy (SEM), and the results show that the surface of hot dip galvanized steel is covered by a spiculate and floccule shape conversion coating. The chemical composition of the surface coating was investigated by energy dispersive X-ray (EDX), which illustrate that the conversion coating is composed of zinc,oxygen, phosphor and molybdenum.

Abstract: We prepared the magnetic cenospheres deposited with magnetite Fe₃O₄ nanoparticles under hydrothermal conditions. The crystalline phase, magnetization properties, morphology, chemical composition and thermal stability of asobtained cenospheres are analyzed by Xray diffraction, vibrating sample magnetometer, scanning electron microscope, Xray energy dispersive spectroscope, transmission electron microscope, thermal gravimetric analysis and differential scanning calorimetry techniques. The results show that the inverse cubic spinel phase of Fe₃O₄ nanoparticles with an average size 50 nm are synthesized, and synchronously deposited on cenosphere surface. As the thickness of Fe₃O₄ coating increases, the saturation magnetization increases to some extent. The growth of Fe₃O₄ nanoparticles can be controlled by adding ethanol to the reaction solution.

Abstract: A new hyper-dispersant with Silicon radicals as anchoring group and poly (butyl acrylate) as solvatable chain was synthesized and its effect on the properties of PE/Talc composites was investigated in this paper. Fourier transmission infrared spectroscopy (FT-IR) results show that the modifier react on the Talc powders surface and the modified Talc powders particles. The impact strength of PE/Talc composites increased about 32.5% compared with that of PE/Talc (filled with same non-modified fraction) respectively. Based on surface analysis by scanning electron microscope (SEM), the Talc powders particles buried well in PE matrix when Talc powders was coated with the new modifier.

Abstract: According to the peculiarities of repairing of coke oven the spraying coating of normal temperature was used. The energy of the coke oven was used by the spraying powder to adhere to the wall of coke oven. The heating time equation of spraying powder has been deduced from thermal radiation equation, and the computer simulated calculation of heating time which is programmed is based on this equation. The possibility of spraying coating reacting in short time and adhering to the coke oven is speculated. The result of adhering of the spraying powder was proved.