Advanced Materials Research Vols. 152-153

Abstract: In order to enhance the visible transmittance, a compact silica film was successfully coated on the surface of VO2 particles by the sol-gel method, using sodium silicate as the coating agent and hydrochloric acid as the neutralization agent. The composition, structure, surface bonding mode and the visible transmittance of the products were characterized by means of XRD, SEM, FTIR and UV-Vis. The results showed that SiO2/VO2 composite particles can produced by this method, and the visible transmittance was higher than the pure VO2. It was a basic study in the applications of the smart coatings based on VO2 powders.

Abstract: In this paper, the microwave dielectric properties in the systems of nominal chemical composition (Mg1-xCax)2SiO4 (0≤x≤0.5)ceramics were investigated, together with their phase evolution. With the increase of x value, the major phase in the ceramic systems gradually changes from Mg2SiO4 to MgCaSiO4, besides with the some secondary phase of MgSiO3 and Ca2MgSi2O7, The relative dielectric constant in the systems of ceramics gradually increased from 6.8 to 8.7. The quality factor of value was well improved, and especially, the absolute value of the ceramic resonant frequency of temperature coefficients was optimized to reach zero, from -61 to +3 . The best optimum chemical composition was equal to 0.4, where the microwave dielectric properties was = 7.2, = 24,170 GHz, = +5 .

Abstract: Thermal shock stability for ZrB2-SiCp-Graphite(ZSC) and ZrB2-SiCp-AlN (ZSA) was investigated by water quenching test. It indicated that ZSC may provide more stable thermal shock properties. As shown by SEM of ZSA, surface cracks appeared after it was cooled from 1200 , due to thermal shock instability of the material. Residual flexural strength of ZSA was improved by crack healing after it was cooled from 1450 . However, no surface crack appeared for ZSC after water quenching test. It provided a potential method for improving thermal shock stability of zirconium diboride ceramic matrix composites by introducing proper quantities of graphite.

Abstract: Numerical control technology is a core of an advanced manufacturing technology, it is the manufacturing industry that realizes the automation, networking, flexibility, integrated foundation. The integral level of the numerical control equipment marks a national industry’s modernized level and power of the overall nation strength. The core of creative product is product conceptual design, creativity is an important characteristics of product conceptual design. The basic principle of TRIZ theories is the foundation of this research. In order to meeting the demand of product design, this research created some applicable tools for product design. As the final research achievement, these applicable tools can be used in the field of numerical control technology.

Abstract: Al-N codoped ZnO thin films were prepared by sol-gel method, which microstructure were characterized by AFM and XPS, on the basis of the result, doping mechanism of Al-N co-doped thin film is: the formation of the first occurrence of Al was replacing doping system of Zn, and it is conducive for N element in the system to the solution along with the increasing of Al doping concentration.

Abstract: The steam reforming of simulated coke oven gas (COG) with toluene as a model tar compound for syngas production was investigated over Ni/Al2O3-MgO catalysts. XRD results showed that the catalysts with high calcination temperature and Al2O3 content after calcination formed (Ni,Mg)Al2O4 spinel and Ni-Mg-O solid solution structure. At optimized reaction conditions, toluene and CH4 can be completely converted, while a H2 yield of 71.8% and a CO yield of 76.1% have been achieved at 800 oC. The catalysts with appropriate calcination temperature and Al2O3 content showed better catalytic activity and resistance to coking, which will be promising catalysts in the catalytic reforming of COG.

Abstract: The styrene-acrylic emulsions were prepared by copolymerization of styrene, acrylic acid and n-butyl acrylate; coatings were achieved by adding calcium sulfate whiskers and titanium dioxides at the presence of dispersing agents and rheological additives. The physical and mechanical properties as well as contact angles of coating films formed on tinplate were characterized in detail. The pencil hardness was slightly decreased; the contact angle was greatly decreased from 69.8o to 12oby adding the calcium sulfate to indicate the hydrophilic coating films may have self-cleaning properties.

Abstract: A grey-white marble/UP composite material was prepared by using marble powder as the filler and Unsaturated polyester (UP) resin as the polymer matrix. Optimum amount of marble powder added into 100 g UP resin was 200g. The gel time and the curing time were 10.5min and 34min respectively, the peak temperature reaches 71.44°C, and heat-resistance temperature was enhanced by 81°C. Marble/UP composite material is smooth, equally distributed, and no aggregation of particles of marble powder.

Abstract: Bis-maleimide (BMI) resins are widely applied in carbon fiber reinforced polymer composites in aerospace fields, for their excellent thermal and mechanical properties. The effects of thermo-oxidative aging on mechanical properties of carbon fiber reinforced BMI composites were investigated by SEM with the combination of flexural strength test and inter-laminar shear strength (ILSS) test. The results indicated that the thermal-oxidative aging had some effects on mechanical properties of carbon fiber/BMI composites; however the testing temperature or service temperature had much more effects than aging time. With aging time increased, the flexural strength at 150 oC and the ILSS at 25 oC slightly increased, while the ILSS at 150 oC decreased gradually. Both test results of mechanical properties and fracture models of damaged flexural specimens by SEM indicated that the matrix resin in the composites showed some viscoelastic behaviors that resulted in the remarkable dependence of mechanical properties of the composites on temperature. Therefore, the carbon fiber reinforced BMI composites had lower flexural strength and ILSS at 150 oC than that at 25 oC.

Abstract: Steel including sulfide inclusion was used as cathode, while high density graphite rod was used as anode. Sulfide inclusion in steel surface was removed by molten salt electrolysis in molten CaCl2 at 850 under the stationary voltage. The influences of the voltage and electrolytic time on the process of reaction were investigated. The distributions of the sulfide inclusion were investigated by SEM. The desulfurated ratio was investigated by quantitative metallographic analysis, Cyclic voltammetry was performed to characterize reactions of cathode. The results show that the voltage and the time of electrolysis were in direct proportion with desulfurated ratio. The higher voltage and the longer electrolysis time is, the greater the desulfurated ratio is.