Papers by Author: Bin Shi Xu

Abstract: In this article, solid lubrication FeS film was prepared on the surface of AISI 1045 steel by means of low temperature ion sulfurizing process. Scanning electron microscopy (SEM) was utilized to observe the surface and cross-section morphologies of the sulfurized layer. The element distribution of the sulfurized layer surface was analyzed by X-ray energy spectrometer. The crystalline phases were determined by X-ray diffraction (XRD). X-ray stress determinator was utilized to measure the residual stress in the sulfurized layer. The nano-hardness and elastic modulus of the sulfurized layer were surveyed by a nano-indentation tester. The results showed that the surface of the FeS film was composed of many minute spherical particles with homogeneous grain size and distribution. The texture of the film was very loose with lots of micro-pores, and the crystallinity was well. There was compressive stress in the FeS film, and the stress value measured is -150 MPa. The average value of nano-hardness and elastic modulus were 4.02 GPa and 157.36 GPa respectively.

Abstract: In this paper, the structure and tribological properties of synthetic MoS2 film prepared by a novel compound technology—combining magnetron sputtering with low temperature ion sulfurizing were investigated. X-ray diffraction (XRD) pattern for the MoS2 film implies that the film mainly consists of Mo and MoS2 phases. The hardness of the synthetic MoS2 film was 7.44 GPa which was higher than that of the FeS film. The sliding tribological behavior of the MoS2 film was studied by ball-on-disc tests. The results showed that the synthetic MoS2 film possessed excellent friction-reducing and wear-resisting properties. In addition, the tribological behaviors of the MoS2 film were superior to those of the FeS film and original 1045 steel.

Abstract: The microstructures of three kinds of synthetical solid FeS, acting as a solid lubricant, which includes FeS bulk, FeS particle and FeS powder, were studied by transmission electron microscope (TEM) in this article. The TEM photographs showed that different shapes of FeS had quite dissimilar characteristics. The texture of FeS powder was the loosest among the three shapes, and it tended to forming flocculent aggregation; while FeS bulk and FeS particle were more dispersive. The electron diffraction results showed that the crystals of solid FeS were composed of many single crystals and multi-crystals, with two kinds of crystalline structure- hexagonal structure and face-centered cubic structure.

Abstract: The most severe corrosion of offshore steel structure occurs in splash zone. There are many factors affecting the steel structure corrosion in the splash zone, such as corrosion problems caused by seawater and effect of impacted brought by the ocean wave. Considering the corrosion characteristics in splash zone and the corrosion invalidity behaviors of offshore steel structure, the Zn-15Al, Al-RE, Zn-Al-Mg-RE and FeBSiNb uncrystal coatings were prepared by automatic high velocity arc spraying. The different anti-corrosion behaviors of the four coatings were studied through the corrosion comparative tests and the microstructures analyzed of the coatings before and after the corrosion tests. The anti-corrosion coating systems suitable for using on surface of steel structure corrosion in the splash zone were found, which provided technique guarantee for extending the using life of offshore steel structures.

Abstract: A series of a-C:H films have been prepared by plasma-based ion implantation (PBII) with acetylene on AISI 321 substrates. The effect of negative bias pulse on the characteristics of these films was investigated. The structures of the films were analyzed by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The surface hardness was measured by microindentation tests. The results indicated that the characteristics of these films are strongly depended on the negative bias pulse. When the bias pulse ranges from -10kV to -40kV, the films are typical diamond like carbon (DLC) films, while the films deposited at -5kV are polymer films. The peak intensity ratio of the D-band to that of the G-band (ID/IG) of the DLC films changes with the negative bias pulse. The minimum value of ID/IG (1.02) was gotten at -10kV.

Abstract: Cored wires and high velocity arc spraying technique (HVAS) were used to produce high Mg content Zn-Al-Mg alloy coatings on low carbon steel substrates. The microstructures, mechanical properties and electrochemical corrosion behaviors of the Zn-Al-Mg coatings were investigated comparing with Zn and Zn-Al alloy coatings. And the electrochemical corrosion mechanisms of the coatings were discussed. The coatings show a typical aspect of layered thermal sprayed material structure. Chemical analysis of the coating indicated the composition to be Zn-14.9Al-5.9Mg-3.0O (wt.%). The main phases in the coatings are Zn, Mg2Zn11, Al12Mg17 and MgAl2O4, together with a little Al2O3 and ZnO. The corrosion potential of Zn-Al and Zn-Al-Mg coatings decreased a little and then increased towards the noble potential. With addition of Mg, the corrosion products accumulated to form stable passive film can block off the pores in the Zn-Al-Mg coating, and thus may prevent attack on the underlying steel substrate. The Zn-Al-Mg coatings show higher electrochemical corrosion resistance in salt solution than Zn-Al coatings.

Abstract: Microstructure and properties of Ni-base coatings obtained by micro-plasma arc cladding was investigated. A uniform clad coating was obtained after optimizing the cladding parameters by using NiCrBSi powder. Microstructure of the coatings observed by optical and scanning electron microscopy (SEM) indicated a homogenized microstructure. It has no evident heat-affected zone and no porosity. The phase of the coating was formed by γ-N solid solution, nickel boride Ni3B, carbide Cr21.34Fe1.66C6 and Cr2B3 type chromium boride. Although it likes the laser cladding coatings, micro-plasma coatings has its own characteristic. In addition, the average microhardness and nanohardness of coatings which were much higher than the substrate were observed, and the distribution of the microhardness was drawn.

Abstract: The nano-effects of nano-Cu lubricating material in equipment maintenance were researched from reducing friction effect, antiwear effect and repairing effect by comparing tribology properties of nano-Cu lubricating material with micro-Cu material. The nano-effect mechanism was discussed. The results indicated that the reducing friction effect and the antiwear effect can make the friction coefficient and the worn track width of lubricant reduce to 16% and 40% respectively. The repairing effect can make the nano-Cu lubricating material forms repairing film on wore surface. That of all is decided by the characteristics of nano-Cu lubricating material.

Abstract: The serpentine is a kind of phyllosilicates whose crystal structure leads to a tetrahedral-octahedral (TO) structure. Because of its unique crystal structure, micro-nano serpentine powders (MSP) in liquid lubricants can show a good tribological performance, so that lots of scholars had started extensive and in-depth studied on its tribological performance. In this research, the raw material which is Xiuyan serpentine produced from Liaoning province, China, had been made into powders with particle average diameter about 0.5 μm. The friction optimized content of MSP in the lubricant oil was studied and it were examined that the loads’ and friction pairs move velocity’s changes had effect to tribological performance in friction course. The results show that the optimal content of MSP in gasoline engine oil SJ10W-40 is 0.5 mass%, under this condition, friction coefficient can be reduced to 0.03, and the friction-reduction performance can been enhanced by 73.3%, so that the lubrication state is that boundary lubrication changes into mixed lubrication. Disclosing the tribological rule of MSP in lubricant oil under the condition of loads and the move velocity of friction pairs changing, and discovering MSP addictive to lubricant oil can extended friction pairs with high move speed and heavy loads working hours, all that can provide a theoretical basis to promote engineering.

Abstract: Being the heat source of arc spray, the characteristics of arc are of importance for properties of coatings. In this paper, the arc shape in the wire arc spray process was analyzed in the aid of high-speed digital camera. It is testified that the arc has the elliptical shape. This type of shape is favorable for heating the metal particles. The arc isn’t always in burning state and it is extinguished frequently. There are two kinds of reasons for arc extinguish. The first one is that the two metal wires short circuit. The second one is that the imperfect melted metal stretches the arc long, and then this part melted and broken away from the metal wires’ tips. If we can control the metal wires state, the properties of coatings will be improved.