Advanced Materials Research Vols. 391-392

Abstract: The latest development of ZrC-SiC, ZrO₂-SiC and ZrO₂-mullite high performance composites synthesized from zircon was reviewed. The future development of synthesizing high performance composites from cheap materials and simple preparation technology was prospected.

Abstract: An experimental study on the influence of cooling rate and manganese content on the structures and phase formation of Fe-Mn alloy was carried out during sub-rapid solidification process. BCC structures were obtained for samples with manganese content ranging from 2pct to 11pct, and a HCP phase was obtained when the manganese content is up to 15pct. The micro- hardness increases with cooling rate and manganese content increasing.

Abstract: A paste with as low as 300°C sintering temperature was prepared by using nano silver particles and nitrocellulose ethyl acetate solution. The rheological and thixotropic behaviors of the typical paste were characterized and their effects on the screen printing ability were analyzed in details. The paste demonstrates a typical shear thinning rheological behavior and thixotropic of pseudoplastic fluid. The apparent viscosity decreased rapidly with the increase of the shear rate. The paste is proper for the manufacturing electrical components at a low sintering temperature as low as 300°C.

Abstract: Tungsten ore doped Al/Cu alloy powder compact was processed by laser combustion synthesis (CS). Optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to study the effect of laser processing and pressing pressure on microstructure and density of the alloy. The results show that the compactness increases, the microstructure is refined and the uniformity is promoted within a certain range. As the relative density increases, the densification of the product increases. The sintered alloy is mainly made from matrix phase of higher toughness mixed up with intermetallic compounds of high dispersion, and nanocrystals, which is compound texture.

Abstract: Coal waste and coal slurry are the largest industrial waste generated from coal preparation plants. This paper describes a method to make clean coal briquette with coal waste and coal slurry. Two binders were used during the coal briquette making process. In addition, a mixture of cacium hydroxide and coal fly ash was added into the formulation acting as a sulfur retention agent. The results show that coal briquette strength and sulfur retention were significantly improved. For example, both wet strength and falling strength reached 99%. The sulfur retention is about 55.41%.

Abstract: This paper adopt computer which is a efficient computational tool, analyzing Dushan inverted siphon structure, researching variation law of the inverted siphon’s stress and displacement in construction process and operational process. Research results further verified rationality and security of the design schemes, which provides reliable reference for construction and operational of inverted siphon structure.

Abstract: On the basis of the analysis of composition, microstructure, properties and weldability of 2205 duplex stainless steel, the flux cored arc welding (FCAW) process is made. Then the microstructure, mechanical properties and corrosion resistance of welded joint were analyzed. The results shows using FCAW process, in order to obtain high strength, perfect impact toughness and overall and partial resistance to stress corrosion in welded joint, the Ni content of duplex stainless steel welding material should be 2% to 4% higher than that of base metal, multi-layer and multi-channel welding is adopted with the strict control of energy input less than or equal to 0.926KJ/mm, layer temperature is less than 120 °C, thus the appropriate proportion of two-phase structure in the welded joint can be got. Using a reasonable welding procedure, the microstructure in weld beam is austenite (A) + ferrite (F), and in heat affected zone is ferrite (F) + austenite (A) + a small amount of third phase, the content of austenite in weld beam and heat affected zone is higher than that of the base metal. Tensile strength of the welded joint is up to 854.5MPa and the fracture occurs in the base metal and the heat affected zone. The welded joint has high strength, good plasticity, toughness and corrosion resistance.

Abstract: The weldablity of dissimilar steel between 16MnR and S31803 was analyzed and researched. By means of optical microscope (OM), the microstructure of the weld joint was investigated, which is welded by tungsten inert gas arc backing welding (GTAW) and manual arc filling welding (SMAW). The mechanical properties and corrosion resistance of the welded joint was also tested and studied. Results indicate that austenite and acicular ferrite distribute uniformly in the weld metal, which strengths the toughness and ductility of the joint. The austenite content in weld is higher than that in over-heated zone of S31803.The SMAW joint structure is coarsening than that of GTAW and has more austenite content. It is also observed that there are a decarburization layer and a carbon-enriched zone nearby the fusion line. And very small amounts of the third phase of harmful metal phase are found in the fusion zone of S31803 side. The welded joint shows the excellent mechanical properties and corrosion resistance. The impact toughness of the weld metal is higher than in HAZ of 16MnR side, and the impact toughness at GTAW side and in HAZ is superior to the SMAW side.

Abstract: A spherical amine modified lignin-base adsorbent had been prepared (L-BAA) by condensation polymerization of lignin with epoxy chloropropane and diamines. The modified products were characterized by FTIR spectra and scanning electron microscopy. Few researches on adsorbing Pb (II) of high concentration from aqueous had been reported. The spherical lignin-base adsorbent was used to adsorb Pb (II) of high concentration from aqueous solution. The effect of shaking time, pH value and temperature on adsorption had been investigated in the study. It was indicated that the adsorption was dependent on pH and temperature of Pb (II) aqueous solution. The maximum adsorption capacity was 151.0 mg/g at follow condition: pH value was 4.00 and temperature was 35°C. The adsorption capacity was better than other reported adsorbents.

Abstract: In this paper, we report a Fe-based nanocrystalline-amorphous matrix composite synthesised via partially crystallising an amorphous alloy. The microstructure of the composite was characterize. An amorphous rod of 2mm in diameter was initially prepared via injecting the melted Fe₃₆Co₃₆B₂₀Si₄Nb₄ alloy into a copper mould in vacuum, which was confirmed to be completely amorphous by X-ray difraction（XRD）. Differential scanning calorimeteric（DSC）curve shown that the span △Tx of the supercooled liquid region and the reduced glass transition temperature（Tg/Tm）for the amorphous alloy are 40 K and 0.615, respectively. The composite composed of nanocrystalline particles homogeneously dispersed in an amorphous matrix was prepared by isothermal annealing. In this course, the amorphous Fe-based sample was held for different time at different temperature. The types of the nanocrystalline phases obtained in different annealing conditions were characterised by XRD and selected-area diffraction pattern（SAED）.The crystallization behavior of the amorphous Fe-based alloy was discussed.