Advanced Materials Research Vols. 472-475

Abstract: In this study, NiCoCrAlY bond coat and two types of top coat including yttria stabilized zirconia (YSZ) and ceria and yttria stabilized zirconia (CYSZ) were deposited on IN 738LC by air plasma spraying (APS). Hot corrosion behavior of samples in 1000 °C was study using 55wt.%V2O5-45wt.%Na2SO4 corrosive salt. Characterization and analysis of results was done by employing field emission scanning electron microscope (FESEM) and x-ray diffractometry (XRD). Results ravealed that plasma sprayed CYSZ TBCs exhibited excellent hot corrosion resistance which was superior to that of YSZ TBCs due to strong acidity and high contents of stabilizer.

Abstract: Models recommendation is always a key part in part-composition system based on sketch. In this paper, proper models are suggested via three steps. Firstly, the possible type of model parts is suggested according to the topological features. Then toy parts that have similar profile types with the inputted sketches are clustered and recommended by lineage clustering method. Finally, based on the promoted $1 recognizer, the suggested parts are sorted according to the shape similarity with the inputted sketch. Experimental results show that the models can be recommended quickly and properly via our method.

Abstract: The post-treatment with Ce-rich sealing of Ni-P coating (Ce-sealed Ni-P coating) was developed on Al surface. Effects of corrosion resistance with different phosphorus contents in the Ni-P coatings were investigated in this paper. The results of the polarization curves show that the Ce-sealed Ni-(10wt.%)P coatings have the higher corrosion potential (Ecorr) and the lower corrosion current (i_corr), indicating that this coating i_{Subscript text}s a better corrosion inhibitor than Ni-(3wt.%)P coating. These results demonstrate that the P content plays an obvious role on improving the corrosion resistance of Ni-P coatings. It is results of SEM analysis shows that the Ce-sealed Ni-(3wt.%)P coating has not obvious micro-cracks, the Ce-sealed Ni-(10wt.%)P surface with some micro-cracks are appeared on Ce-rich coating. But this micro-cracks phenomenon of Ce-rich coating can not effect on corrosion resistance. Otherwise, there are no peaks of Ce-riched coatings in both XRD patterns, because too less Ce elements and non-crystal tendency is more serious on these coatings.

Abstract: Ag doped TiO2 was formed on the surface of carbon nanotube(CNT) by the sol-gel method, and characterized by TEM, XRD. The photocatalytic activity of the Ag-TiO2 /CNT was evaluated in degradation of methyl orange with a 300 W high pressure mercury lamp. Effect of Ag doping quantity on the photocatalytic activity of the photocatalys was investigated.The photocatalytic experiment indicated that the photocatalytic activity was firstly improved and then decreased with an increase of amount of Ag doped in TiO2 nanoparticles,the optimal doping quantity was 0.8% silver （ mass fraction of TiO2）, methyl orange could be degraded 99.3 % by Ag-TiO2/CNT under the optimal conditions after 120min.

Abstract: This paper represents a summary of experimental results dealing with the time dependence of surface diffusion alloyed microstructure and its corrosion behavior at given temperature. The experiments were performed at 485°C for different solid diffusion time (6h, 12h, 18h ) and thus the surface alloyed microstructure of pure magnesium has been obtained. Optical and electrical microscopy and EDS compositions analysis were used to examine the cross sectional microstructure characteristics of alloyed layers of treated samples. It is shown that the new phases formed and its continuity, depending on the diffusion treated time at given temperature, have a noticeable influence on corrosion resistance and corrosion mechanism. The new formed phase Al5Mg11Zn4 was inert to the chloride solution compared with pure magnesium and acted as a corrosion barrier. It was concluded that the continuous Al5Mg11Zn4 phase was beneficial from the point of view of corrosion resistance.

Abstract: A series of Fe-xCr-C hardfacing alloys were successfully fabricated on a substrate of 20g steel by gas tungsten arc welding (GTAW) process. These claddings were disigned to observe hypoeutectic, near-eutectic, and hypereutectic structures with various Cr3C2 and M7C3 carbides at room temperature. According to X-ray diffraction(XRD) and optical microscopy (OM), the hypoeutectic and eutectic composites include the Fe-Cr solid solution(α+A) and Cr3C2 carbides. Hypereutectic structures consist of α+A+M+M7C3 respectively. The cladding of hypereutectic microstructure with great amounts of primary M7C3 carbides had the highest hardness of the all conditions.

Abstract: A parametric fault model of electro-hydraulic servo system based on hybrid system and multiple linear regression model was put forward. First of all, the operating condition of electro-hydraulic servo system was abstracted to discrete states, then using multiple linear regression algorithm, the model parameter were identified based on the statistical analysis of sample data. Finally, an electro-hydraulic servo system fault model was constructed combining the fault parameter. Compared to the previous fault model based on experimental modeling method, this model was constructed based on pressure, flow rate sensor data fusion, two parameters are correlated in the base layer, which can effectively improve the diagnostic decision robustness. The parametric fault monitoring and diagnosis experimental showed the effectiveness in fault monitoring.

Abstract: In textile enterprise, the monitoring and maintenance of equipments is a big problem. There are many inconvenience by traditional wiring way, and this paper puts forward a remote monitoring system based on ZigBee technology with low cost and high efficiency. Through ZigBee network, this system transfers the data collected from on-the-spot equipments to center control computer, so as to realize the remote monitoring. The monitoring system has the advantages of network organizing flexible, low cost, big network capacity and so on, which particularly suitable for textile enterprise.

Abstract: Based on the Biot theory and laboratory data, engineers of LandOcean recently develop a certain technology for hydrocarbon detection in multi-phase medium in order to reduce ambiguity and uncertainty. The sensitivity of the technology is superior to others especially in carbonate pores and cave detection, igneous hydrocarbon prediction and fluid detection of non-well areas. A number of projects and wells drilling proved that this technology is effective and reliable.

Abstract: In this work, the displacement instability of thermally grown oxide (TGO) occurring near the surface groove in Fecralloy substrate subjected to multiple purely thermal cycling, has been simulated coupled with crack propagation in TGO layer using finite element method. Due to insufficiency in the traditional criterion of crack opening displacement (COD), a modified COD criterion is employed to model crack propagation in TGO layer as thermal cycles in which the required input parameters are continually modified as thermal cycling based on the calculation result. The comparison between FEA and experimental results shows a good agreement indicating the validity and accuracy of the simulation, which may provide a solution for future works on more complicated case such as in thermal-mechanical cycling.