Advanced Materials Research Vols. 189-193

Abstract: Different adsorptive mediums and adsorbents’ compounds were chosen to remove arsenic from Yangzonghai Lake wastewater. Results showed that Ca(OH)₂, attapulgite, bentonite, LDHs these adsorptive mediums had adsorptive capacities of less than 2.5 mg/g of As removal and it took long time for sediment before monitoring; adsorbents compounds’ results showed Fe₂O₃ and quartz sands had best removal rate and quartz sands had little removal of arsenic. Both strong anion resin and hydrated ferrous oxide-loaded on polystyrene diethanolamine resin(designated as PDR-HFO) can decrease As concentration to less than 0.01 mg/L reaching national standards for arsenic; anions such as SO₄^2- can not be removed when strong anion resin was regenerated causing its loss of exchange ions; PDR-HFO exhibited excellent adsorptive properties and recyclability.

Abstract: In the present work, ultra-fine Al₂O₃/ZrO₂-MgO-CeO₂ powders were used as the starting materials to produce Al₂O₃-ZrO₂ composite coatings on 45# carbon steel by flame spray. The ultra-fine Al₂O₃/ZrO₂-MgO-CeO₂ powders were prepared via the co-precipitation method accompanied a crushing sintering process. The microstructure, the phase compositions and the bond strength of the crushed sintered powders and the corresponding composite coatings were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and a tensile bond strength tests respectively. It was found that the phase composition, the surface topography and the coating adhesion were different from the difference kinds of coatings. Results indicated that the phase composition of the flame sprayed ceramic coatings consisted of tetragonal-ZrO₂, cubic-ZrO₂, ZTA (zirconia toughened alumina) and γ-Al₂O₃, with a small amount of α-Al₂O₃, and that bond strength values attained 45.1 MPa for 42.6wt.% Al₂O₃/57.4wt.% Mg_0.13Ce_0.1Zr_0.77O_1.87 coating.

Abstract: The efficiency-reinforcement design framework of hydraulic reciprocating sealing driven by ideal solution is proposed. The seals’ main operating characteristics, seal efficiency control, leakage control and friction losses control are analyzed. The efficiency-reinforcement sealing element is designed according to TRIZ ideal final result searching strategy, sealing mechanism and tribological behavior. The computational model of efficiency-reinforcement sealing element is established with ANSYS, and its stress, strain and contact pressure distribution in different fluid pressure are also analyzed. The results demonstrated that the presented seal element outperforms the old seal in efficiency reinforcement capacity.

Abstract: The photocatalytic degradation of phenanthrene (PHE), pyrene (PYRE) and benzo[a]pyrene (BaP) on soil surfaces in the presence of Fe₂O₃ using ultraviolet (UV) light source was investigated. The effects of various factors, namely Fe₂O₃, soil pH, and humic acid, on the degradation performance of polycyclic aromatic hydrocarbons (PAHs) were studied. The results show that photocatalytic degradation of PAHs follows the pseudo-first-order kinetics. Catalyst Fe₂O₃ accelerated the photodegradation of PHE, PYRE and BaP significantly. In acidic or alkaline conditions, the photocatalytic degradation rates of the PAHs were greater than those in neutral conditions. Humic acid significantly enhanced the PAH photocatalytic degradation by sensitizing radicals capable of oxidizing PAHs.

Abstract: In order to improve the reliability and security in production, effectively checking and maintaining equipment must be put into practice. In this paper, the on-condition maintenance period of the equipment is optimized by Monte-Carlo for the lowest maintenance cost in unit time by expressing the maintenance interval as an exponential function parameterizing Weibull’s distribution function。Finally, the oil centrifugal pump as an example was demonstrated. The results show that our model has the obvious economic benefits. The optimization analysis of equipment maintenance based on Monte-Carlo provides a theoretical basis for optimized detection and maintenance decisions.

Abstract: Fe-based amorphous alloy coating with a composition of Fe₄₁Co₇Cr₁₅Mo₁₄C₁₅B₆Y₂ was prepared by high velocity fuel(HVOF) technique. The influence of heat treatment on crystalline behavior, the phase structure and corroded morphology of the coating was investigated by Differential Thermal Analysis(DTA), X-ray Diffraction (XRD), Scanning Electron Microscopy(SEM), respectively. The experimental results indicate that the amorphous alloy coating exhibited a two-step crystallization process with crystallization peak temperature at 698°C and 822°C, respectively. Amorphous coating exhibits excellent corrosion resistance than that of the corresponding nano-crystalline coating with heat treatment at 700°C for 2h, 8h and 12h. Furthermore, the nano-crystalline coating annealed 700°C for 12h suffers slight homogeneity corrosion, which did not exhibit obvious pitting on comparison with coating holding 2h and 8h.

Abstract: In this paper, five kinds of power ultrasonic transducers with different section plane positions are designed and the shapes of the transducers are straight. The different section plane position changes with the length l2 of front cover. That is to say, the longer l2 is, the more front the position of the section is. The experiment indicates the great influence of the section plane position on the transducer performance.With the increase of the length of the front cover, the dynamic resistance reduces gradually, and the resonance frequency and the anti-resonance frequency also reduce. Under this condition, the anti-resonance frequency declines more sharply, and the mechanical quality factor increases gradually, but the effective mechanical and electrical coupling coefficient reduces gradually. The transducer has different measure targets in different situations. Therefore, different parameters may be primordially considered to be designed according to the actual use of the transducer in this paper. This provides the reference for manufacture and use of transducers.

Abstract: Hardness of electronless Ni-P plating with 10.98wt.% P content was investigated. Heat treatment temperature and time of the plating was optimized by Uniform Design method. Structure of the plating was analyzed by XRD method. The results show that correlation consist between maximum hardness of the Ni-P plating and heat treatment temperature, not heat treatment time under the experimental condition, and max. of the plating hardness appears when the heat treatment is about 430°C . With increase of heat treatment temperature, structure of the plating transitioned gradually from amorphous state to crystalline state, and Ni₃P crystal grain grown up, and it affect hardness of the plating.

Abstract: NiAl and Ni₃Al intermetallic compound claddings are prepared by argon arc cladding technology on the 16Mn steel substrate. These claddings were oxidized for 100 hours at 850 and the oxide quality of each sample was recorded every 10 hours. The results show that the NiAl and Ni₃Al claddings have homogeneous structure and few defects, and form excellent metallurgical bonding with the matrix. The oxidation kinetics results show that, the oxidation weight gain rate of NiAl was more stable than Ni₃Al and tended to zero earlier. Oxide layer spallation of Ni₃Al cladding was more serious than that of NiAl cladding. Thus, NiAl argon arc cladding has the more excellent high temperature oxidation properties than Ni₃Al argon arc cladding.

Abstract: In ITER D-T fuel will be used for fusion plasma. Therefore a material capable of acting as a tritium permeation barrier on stainless steel is required. It is well known that thin alumina layer can reduce the tritium permeation rate by several orders of magnitude. A technology is introduced here to form a ductile Fe/Al layer on the steel with an alumina over-layer, which consists of two main steps, hot-dip aluminizing (HDA) and subsequent oxidation process. According to the experiments that have been done, Fe-Al intermetallic layer and outer aluminum coat were formed after the HDA process. In this report, we have studied the influence of temperature and oxygen pressure on the formation of ductile phases and alumina over-layer in the oxidation treatment. At the temperature of 900°C, the brittle Fe-Al intermetallic layer and aluminum coat transformed into ductile phase (FeAl and α-Fe(Al)) and a γ-Al₂O₃ over-layer was formed under the oxygen pressure about 5Pa. It was found that the low pressure of environment suppressed the formation of pores or cracks as well.