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This paper reviews several innovative techniques that have been developed in our labs to overcome the shortages of conventional sol-gel techniques, and discusses the technical details of preparing these ceramic coatings with controllable thickness, microstructure, composition and improved properties. [ABSTRACT FROM AUTHOR]

The theory studies have showed that, rock burst is a kind of dynamic phenomenon of rock mass in mining, and is a kind of dynamic disaster from mining. The time series of magnitude is a very important exterior behavior of rock burst. The previous studies show that, to model this complicated non-linear time series, the neural network is a very good method. To overcome the shortcomings of traditional neural network, a new kind of evolutionary neural network based on immunized evolutionary programming proposed by author is proposed here. At last, the proposed evolutionary neural network model is verified by a real magnitude series of rock burst. And the result is compared with other method, such as grey system method. The results have showed that, evolutionary neural network model not only has high approaching precision, but also has high predicting precision, and is a good method to construct the non-linear model of rock burst. And this method can be used in a large number of engineering examples. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) and its alloys are being used as structural components in industry because of their high strength-to-weight ratio and relatively high stiffness. A shortcoming of Mg based alloys is their poor corrosion and wear resistance. Therefore, coatings or surface treatment are needed for protection purpose. This paper reports our work on electroless plating of Ni-P on Mg alloys. Pure Mg, AZ31 and AZ91 Mg alloys were used as the substrates to investigate friction and adhesion properties of the electroless Ni-P coatings. The maximum friction coefficient (~0.3) was found on the electroless nickel coating of pure Mg substrate. The adhesion strengths of the coatings on AZ31 and AZ91 Mg alloys are higher than that on pure Mg. The critical load (a measure of adhesion strength) of AZ31 reached 13.1 N. [ABSTRACT FROM AUTHOR]

The forming or shaping of ceramic micro-tubes is usually difficult with conventional ceramic processing. In some cases, parts that are not possible to produce by any other techniques can be fabricated with electrophoretic deposition process (EPD). In this paper, EPD is shown to be an operationally simple, rapid, and reliable technique for forming a wide range of ceramic micro-tubes required in electronic devices such as actuators, motors, optical modulators and MEMS. These topics will be discussed in detail. [ABSTRACT FROM AUTHOR]

Oxidation behaviours of SiC and TiC particulate reinforced Ti[sub 3]Al intermetallic matrix composites at 700-800°C have been studied. The results showed that composites had lower oxidation rates than the cast Ti[sub 3]Al. The most encouraging improvement is that they all possess excellent scale spallation resistance, no spallation could be observed from the composite specimens during all tests. Based on SEM and XRD results, the mechanisms of oxidation and spallation for these composites were discussed briefly. [ABSTRACT FROM AUTHOR]

A preface for the October 20, 2006 issue of the "International Journal of Modern Physics B: Condensed Matter Physics; Statistical Physics; Applied Physics" is presented.

In this study, constitutional liquation in AZ91 cast alloy at 440°C and 465°C was experimentally simulated. Metallurgical examination was conducted to reveal the morphology of the constitutional liquid and dihedral angle was measured to evaluate the wettability of the liquid on grain boundary. Dihedral angle was found to be initially ~30 degree and thus grain boundaries were incomplete wet. During annealing, the metastable constitutional liquid resolidified, followed by grain growth. The extent of grain boundary wetting by the remaining liquid increased slightly with treating time. The rate of resolidification was also evaluated and the factors affecting this rate were discussed. [ABSTRACT FROM AUTHOR]

Well-crystallized zeolite beta is first synthesized in the anionic emulsion systems of cyclohexane/sodium dodecylbenzenesulfonate(SDBS)/pentanol/zeolite synthesis mixture. Beta materials are then characterized by XRD, SEM, and N2-adsorption techniques. Compared to beta samples grown using the same synthesis mixture in the absence of the anionic emulsion, the as-synthesized beta presents uniform and well-defined larger crystals. Interestingly, N2-adsorption results show that such beta sample possesses both ordered mesopores at 3.9 nm and macropores centered at 60.5 nm. These pores combined with the intricate micropores of the Beta crystal comprise the hierarchical porosity. The hierarchical pore-structured zeolite beta may have potential catalysis application in reactions involving large molecules. Additionally, control experiments are also performed to ascertain the effects of the individual emulsion components. Further synthesis study finds the transformation of zeolite beta to ZSM-5 through increasing oil contents, crystallization temperature and time. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study Cu diffusion in polymethylsiloxane (LKD-5109) low-k dielectric material manufactured by JSR Micro with respect to applied thermal energy acting alone. Previous study on low-k dielectric thin film uses a combination of electrical and thermal stress to study Cu diffusion producing a combined activation energy. In this paper, a secondary-ion mass spectrometry (SIMS) was used to determine copper diffusion into LKD-5109 thin film on samples baked/annealed at different temperatures ranging from 373K to 573K in forming gas (7%H2/93%N2). The results showed that the thermal activation energy (Ea) of Cu thermal diffusion is approximately 0.14eV for baking/annealing temperature ranging from 373K to 523K. The Ea will increase to greater than 0.58eV for temperature above 523K with Cu oxidation. The increase in Ea suggests a transport mechanism due to Cu oxidation where oxidized Cu is a source of copper ions that diffused through the low-k dielectric film. [ABSTRACT FROM AUTHOR]

CaCu3Ti4O12 (CCTO)–poly(vinylidene fluoride (PVDF)) composites were prepared by melt blending and hot molding techniques. The addition of CCTO remarkably enhanced the dielectric properties and the thermal conductivity of PVDF composites, while the melting point of the PVDF composites (~170°C) was almost independent of the CCTO concentration. Based on the results of dielectric constant and dielectric breakdown voltage, the PVDF composite containing 40 vol.% CCTO fillers shows the optimized capacitive energy storage potential (7.81 J/cm3). [ABSTRACT FROM AUTHOR]

Copper (Cu) is widely used as electrical conducting and contacting material. However, Cu is soft and does not have good mechanical properties. In order to improve the hardness and wear resistance of Cu, sol-enhanced Cu–Al2O3 nanocomposite coatings were electroplated by adding a transparent Al oxide (Al2O3) sol into the traditional electroplating Cu solution. It was found that the microstructure and mechanical properties of the nanocomposite coatings were largely influenced by the Al2O3 sol concentration. The results show that the Al2O3 nanoparticle reinforced the composite coatings, resulting in significantly improved hardness and wear resistance in comparison with the pure Cu coatings. The coating prepared at the sol concentration of 3.93 mol/L had the best microhardness and wear resistance. The microhardness has been improved by ~20% from 145.5 HV (Vickers hardness number) of pure Cu coating to 173.3 HV of Cu–Al2O3 composite coatings. The wear resistance was also improved by ~84%, with the wear volume loss dropped from 3.2 × 10-3 mm3 of Cu coating to 0.52 × 10-3 mm3 of composite coatings. Adding excessive sol to the electrolyte deteriorated the properties. [ABSTRACT FROM AUTHOR]

The thixoformability and defect formation of AZ91D magnesium alloy are studied with different processing parameters including reheating temperature, time and die temperature. The results indicated that the suitable processing parameters should be reheating temperature between 575-595°C, reheating time more than 75 min, and die temperature over 275°C. Four types of defects, coldshut, liquid segregation, microporosity and cracks, have been observed in the thixoformed products if the processing parameters are not controlled properly. Among these defects, microporosity and cracks are always dominant. [ABSTRACT FROM AUTHOR]