Advanced Materials Research Vols. 634-638

Abstract: The nano surface engineering technology mainly concludes the nano-materials electric brush plating technology, nano-materials thermal spraying technology and nano-films solid lubrication technology. Through the nano surface engineering, the films or coatings possessing the nano-structure characteristics can be prepared, improving remarkably the wear-resistance, anti-corrosion and fatigue-resistance of the substrate. Although the nano surface engineering enriches the maintenance methods and advances the maintenance effects, it still stands the elementary development period and many fundamental issues deserve to research in depth.

Abstract: Cathodic plasma electrolysis (CPE) is an emerging surface engineering technology in the recent years. In present work CPE was successfully used for deposition Ni-P coatings on carbon steel. The deposition experimental results show that CPE possesses high coating deposition rate, faster than 4 μm/min. SEM observations unveil the bonding between Ni-P coating and substrate is metallurgical. XRD diagram analysis indicates that the phases of as-deposited Ni-P coating are Ni and Ni3P, transformed from amorphous to crystallized state. The corrosion resistances of CPE and electroless plating (EP) coating have also been discussed by polarization curves in 3.5% NaCl solution at room temperature. Scratch tester was applied to study film-substrate adhesion of CPE Ni-P coating comparing with EP Ni-P coating.

Abstract: The porous titanium alloys containing molybdenum elements have been prepared by gel-casting methods. The composite coatings with hydroxyapatite (HAP) and TiO₂ were prepared on the precursor in this study. The microstructure was examined by scanning electron microscopy (SEM) and X-ray diffraction, and part of the coatings was examined by EDS to indicate the linear distribution of HAP and TiO2. The Solid content of gel-casting of water base can reac_{Subscript text}h 35%，and porosity can reduce to 42% after sintering.

Abstract: In this study, water-based polyurethane coating with anti-graffiti property was prepared. The pot life and volatilization process of volatile matters of the coating were investigated. General properties of pencil hardness, flexibility, adhesion and impact resistance were tested. Along with the increase of anti-graffiti additive in coating formulation, the anti-graffiti performace of the resulted film was improved. Atomic force microscopy (AFM) was also carried out to determin the roughness of the coating surface.

Abstract: Erosion wear is an important failure mode existing in hydropowder, petroleum, chemical industry and other fields. Nanostructured WC-Co materials possess excellent erosion wear resistance due to their outstanding combination of high hardness and excellent fracture toughness. Nanostructured WC-12Co coating was prepared by means of High Velocity Oxygen Fuel (HVOF) spraying technology in this research. The simulating experiment system was developed to study the erosion wear properties. The corundum sand with main composition of Al2O3 was used to investigate the dynamic erosion properties of nanostructured WC-12Co coating. The dynamic failure mechanism of the coatings was also analyzed by Scanning Electron Microscope (SEM). The results show that the coating is worn layer by layer in the erosion test. The bonding between the layers and the thickness of the coating should be increased to elongate the coating life.

Abstract: At presant, most of the insulated coatings for non-oriented electrical steels contain chromium, and which need to be cured at a higher temperature. On the basis of analyzing the characteristic of the film-forming substance, a environment friendly insulated coating that have lower curing temperature for non-oriented electrical steel sheet is developed and coating process is studied as well, then measured the adhesion, insulation resistance, heat resistance, corrosion resistance and other properties of the coating. The results showed that, the coating can be fast-curing from 150°C to 250 °C, film of the coating is smooth, compact and uniform, and has excellent performance. So the new coating can meet the application requirement of the small and medium-sized motor.

Abstract: Two Novolac Resins Were Synthesized by the Reaction between Bisphenol A and Benzaldehyde (bis-BENR) or Bisphenol A and P-hydroxybenzaldehyde (bis-PHNR). Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) Were Applied to Characterize the Molecular Structure of Bis-BENR (or Bis-PHNR). then the Two Novolac Resins Were Used as Curing Agent for Bisphenol A Type Epoxy Resin (DGEBA). the Curing Reaction and Curing Kinetics Were Studied by Dynamic FTIR and Differential Scanning Calorimetry (DSC). Dynamic FTIR Showed that the Two Novolac Resins Reacted with Epoxy Resins and Formed a Crosslinking Network Structure. DSC Results Show that the Optimum Mass Ratio between DGEBA and Bis-BENR (or Bis-PHNR) Was 7:3, under which the Curing Reaction Processed Completely. the Mechanical Properties and Sulfide Resistance of DGEBA/bis-BENR (or Bis-PHNR) System Were Also Investigated. the Results Showed that when the Mass Ratio between DGEBA and Bis-BENR (or Bis-PHNR) Was 7:3, the Curing Coatings Had Optimum Mechanical Properties and Sulfide Resistance.

Abstract: Based on the first-principles pseudopotentials and the plane wave energy band method, the adsorption behaviors of CO molecules on β-SiC (001) surfaces have been investigated in this paper. The calculations for stable adsorption site demonstrate that CO molecule is adsorbed at the lattice site of β-SiC. The absorbing energy of CO on SiC (001) surface is 2.984eV while the exclusion energy between CO reaches 2.965eV. The densities of State of CO became wider and it extends to lower energy when they adsorbent atβ-SiC (001) surfaces.

Abstract: Thermal fatigue test was performed with cycle heating method to compare thermal fatigue behaviors of 8407 steel samples with and without aluminization and oxidation treatment. Thermal fatigue crack morphology formed on the surface was observed by SEM. The anti-thermal-fatigue mechanism of Fe₃O₄•Al₂O₃ complex oxide was clarified. The results show that, the formed oxide film with surface aluminization and oxidation treatment of 8407 steel is compact and has higher strength and hardness, which can improve both the initiating resistance and propagating resistance of thermal fatigue crack, thus improving anti-thermal-fatigue property of 8407 steel.

Abstract: A simple approach for the synthesis of Ortho Phthaloyl Chloride(OPC) was studied .Response surface methodology (RSM) was used to optimize the synthesis conditions of OPC. A 4-factor central composite design (CCD) was used for experimental design and analysis to obtain the optimal processing parameters, such as amount of triphosgene(BTC), amount of catalyst, reaction temperature and time. The 3-D response surface and the contour plots derived from the mathematical models were applied to determine the optimal conditions. The optimum reaction conditions were as follows: amount of BTC 62 g, amount of cat. 3.3 g, reaction temperature 75°C, reaction time 5 h. Under these conditions, The yield of OPC was 96.61%. Comparison of predicted and experimental values revealed good correspondence, implying that empirical model could be used to adequately describe the relationship between the factors and response in OPC synthesis process.