Advanced Materials Research Vol. 749

Abstract: This paper briefly reports on the improved properties and bettered applications of some piezoelectric ceramics (i. e. S-PZT, etc.) of ferro/piezoelectric community by means of bettering their technological process links, especial superfine grinding of powder of raw materials, and sintering technique of piezoelectric ceramics in them. These piezoelectric ceramic materials have obtained the better effect in their newly and widely applied aspects, such as, acoustoelectric transducing; electrical to mechanical to electrical transducing; acoustooptic effect; electrooptic technique, and, piezoelectric ceramics for high voltage generators, ignition and detonation purposes, and some original applications (e.g., combining the electrorheological fluids) etc.. As far as appropriate measure of the improving sintering and other technique processes in present work is concerned, they also have reference value to electronic ceramics of having similar manufacturing technological process, such as capacitor ceramics, resistance ceramics, magnetic ceramics, and oxide ceramic superconducting materials, etc..

Abstract: Ca₃Co_4xCu_xO₉ (0x1.4) misfit-layered thermoelectric oxides were prepared by traditional solid-state reaction method which cost less, operate easer, may produce Ca₃Co₄O₉ on large scale. XRD study shows that we obtain Ca₃Co₄O₉ major phase in series Ca₃Co_4xCu_xO₉ (0x1.4) samples which were sintered at the highest temperature 880°C for 8h by two steps. Metallographic microscopic analysis indicates that some samples grain size range at 2~4μm which were doped less Cu. Doping Cu in different way experiment suggests that Ca₃Co_4xCu_xO₉ (x=0.4) sample has lower electric resistivity while Ca₃Co₄O₉+5%Cu samples resistivity increases, compared with Ca₃Co₄O₉ (x=0). The article infers that Ca₃Co_4xCu_xO₉ (0x0.4) can decrease the electric resistivity of Ca₃Co₄O₉.

Abstract: At nowadays the interest of forging shops is focused on technology of accurate die warm forging. It is possible to reach higher exploitation of material, higher surface quality and higher accuracy of forgings in comparison to standard forging. The advance of warm forging relates to research of ductility and plasticity of forged material in warm temperature range. This paper provides the results of the research of 16MnCr5 steel forgeability in the interval of temperatures of warm forging. Steel alloy 16MnCr5 is proper for case hardening and for the production of precision die forging. In this paper the description of methodology for the proper interval setting of temperatures of warm forging for the given type of steel can be found. Practical test and a numerical simulation has proven the propriety of the examined steel for forging in the temperature interval 600, 650, 700 and 750 °C. For the steel forgeability verification in the recommended interval of warm forging temperatures, the technological test of upsetting according to Zidek was used.

Abstract: A biodegradable co-polymer, Poly (butylene succinate-co-butyene terephthalate) (PBST) was fabricated into nanofibers by electrospinning. A 4-factor 3-level L 9(3⁴) orthogonal experimental design was employed to examine the effects of process parameters on morphologies of PBST nanofibers. The results showed that the weight concentration = 13wt%, the applied voltage = 20kV, the spinning speed = 0.5ml/h, the electrode distance = 10cm and the diameter of needle = 0.7mm were identified as the optimum conditions.

Abstract: Considering the characteristics of the multilayered ultra-thin sheet stainless steel, by chosen the proper equipments and stored energy welding technology, the optimizing welding parameters are got from the condenser discharge spot welding experiments. The energy stored in the capacitor group is controlled by the energy required during welding and the discharge current is controlled by the size of dynamic resistance in resistance spot welding. So those control ways can better solve the hard problem of choosing welding parameter. The joint strength of ultra-thin sheet stainless steel is ensured by the reasonable quality assessment methods. The processed spot-welded joints are of good quality and appearance.

Abstract: This paper was written based on the testing of resistance to stretch & set and bond strength for 10 different kinds of automotive seating fabrics and their corresponding surface monolayer fabrics, according to the standard GMW3211FZT01034-2008/FZT70006-2004GMW3220. And the results indicated that, resistance to stretch & set of knitted automotive seating fabrics decreased and that of woven fabrics increased after composited; bond strength of fabric/sponge was higher than that of sponge/bottom, and bond strength of seating fabrics which had different structures were also different. Studying the performance of automotive seating fabrics had important implications on the production of seating fabrics, and the improvement of product quality and innovation in future.

Abstract: Iron, chromium or tin containing mesoporous materials MSU-X were synthesized using Pluronic F127 as templating agent under the neutral pH condition by one-step method. The samples were characterized by XRD, N2 adsorption, TEM, FT-IR, UV-Vis. The surface acid nature of Sn-MSU-X was investigated by FT-IR of pyridine adsorption. The results indicate that Fe, Cr and Sn have been successfully incorprated into the framework of the MSU-X samples. And these samples have an uniform pore size distribution. Fe-MSU-X and Cr-MSU-X exhibit disordered worm-like mesostructure. However, Sn-MSU-X exhibits highly ordered hexagonal-pores mesostructure. The Fe-MSU-X and Cr-MSU-X catalysts are more active for the selective oxidation of phenol and cyclooctane, respectively.There are both Lewis and Brönsted acid sites on the surface of Sn-MSU-X.

Abstract: The effect of sintering process parameters on the properties of 3 mol% yttria partially stability zirconia (3Y-PSZ) ceramics has been investigated. The relative density of the sintered pellet rapidly increases from 70.5 to 93.6 % with rose temperature from 1473 to 1573 K. In addition, the relative density only slightly increases from 94.9 to 96.6 %, when rose sintered temperature from 1573 to 1773 K. This result shows that no significant influence on the densification behavior when sintering at 1573 to 1773 K for 2 h. The Vickers hardness and toughness also increase with the sintered temperature.

Abstract: Oxidized cellulose acetate (OCA) with carboxylic acid group on C-6 position of glucose is a kind of biodegradable functional materials which can be dissolved in organic solvents. First, cellulose was oxidized with TEMPO (2, 2, 6, 6-tetramethyl-piperidyl-1-oxyl) oxidation system, and then OCA was produced via esterification by reacting the oxidized cellulose with acetic anhydride. The influence factors such as carboxylic content of oxidized cellulose, reaction temperature, reaction time, and concentration of acetic anhydride on degree of substitution (DS) of acetyl group and intrinsic viscosity ([η]) of OCA were investigated. The result revealed that the DS of acetyl group can be increased effectively from 2.61 to 2.74 by increasing reaction temperature from 50°C to 80°C, and from 2.58 to 2.72 by prolonging reaction time from 40min to 180min, but the [η] of the product decreased at the same time. An increase in concentration of acetic anhydride led to an increase in DS and [η] of OCA. As the carboxyl content increased from 0.383 mmol/g to 0.797 mmol/g, the DS of acetyl group decreased from 2.81 to 2.73. That result revealed the carboxyl content also has a great influence on the esterification characteristics.