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A comparative study was conducted by using solution combustion synthesis with three different doping routes (liquid−liquid (WL10), liquid−solid (WLNO) and solid−solid (WLO)) to produce nanoscale powders and further fabricate the ultrafine-grained W−1.0wt.%La2O3 alloys by pressureless sintering. Compared with pure tungsten, W−1.0wt.%La2O3 alloys exhibit ultrafine grains and excellent mechanical properties. After sintering, the average grain size of the WLO sample is larger than that of WL10 and WLNO samples; the microhardness values of WL10 and WLNO samples are similar but larger than the value of WLO sample. The optimized La2O3 particles are obtained in the WL10 sample after sintering at 1500 °C with the minimum mean size by comparing with WLNO and WLO samples, which are uniformly distributed either at grain boundaries or in the grain interior with the sizes of (57±29.7) and (27±13.1) nm, respectively. This study exhibits ultrafine microstructure and outperforming mechanical properties of the W−1.0wt.%La2O3 alloy via the liquid−liquid doping route, as compared with conventionally-manufactured tungsten materials.

3D carbon fiber needled felt and polycarbosilane-derived SiC coating were selected as reinforcement and interfacial coating, respectively, and the sol−impregnation−drying−heating (SIDH) route was used to fabricate C/Al2O3 composites. The effects of SiC interfacial coating on the mechanical properties, oxidation resistance and thermal shock resistance of C/Al2O3 composites were investigated. It is found that the fracture toughness of C/Al2O3 composites was remarkably superior to that of monolithic Al2O3 ceramics. The introduction of SiC interfacial coating obviously improved the strengths of C/Al2O3 composites although the fracture work diminished to some extent. Owing to the tight bonding between SiC coating and carbon fiber, the C/SiC/Al2O3 composites showed much better oxidation and thermal shock resistance over C/Al2O3 composites under static air.

FeS2/Fe composites were mechanochemically prepared with iron powder and pyrite for the stabilization of ferrite arsenate sludge (FAS). The effects of preparation parameters on stabilization performance were investigated. The results show that the optimum conditions are FeS2/Fe molar ratio of 5:5, milling time of 2 h, ball-to-material mass ratio of 15:1 and milling with stainless steel ball. Then, the composites were characterized by XRD, SEM, FTIR, etc. The physicochemical properties of FeS2/Fe mixture change dramatically, which is responsible for its excellent performance. Finally, the stabilization process of FAS was optimized. When the FAS is mixed with composites at mass ratio of 4:1 and milled for 30 min, the As leaching concentration of FAS can be reduced from 639.15 to 4.74 mg/L with the stabilization ratio of 99.2%.

The structure and the migration mechanisms of { 10 1 ¯ 2 } twin boundaries (TBs) of pure zinc deformed by rolling were studied using high-resolution transmission electron microscopy (HRTEM) at atomic scale. We found the presence of basal/prismatic (BP/PB) planes serrations on { 10 1 ¯ 2 } TBs and the coexistence of two kinds of TBs with different structures in the same { 10 1 ¯ 2 } twin: TBs composed of { 10 1 ¯ 2 } coherent twin boundaries (CTBs) plus short BP/PB serrations, and TBs composed of successive BP/PB segments without { 10 1 ¯ 2 } CTBs. The formation of BP/PB serrations has no relation to the c/a ratio of hexagonal-close-packed (HCP) metals because the BP/PB serrations are energetically preferred and geometrically favored. Based on dislocation theory, we proposed the migration mechanisms of the TBs to be the glide of twinning dislocations (TDs) on the CTBs and the climb of interface dislocations (IDs) on the BP/PB segments.

The effects of the preparation procedure on the formation of crystal phases and catalytic performance of the MoVTeNbO mixed metal oxide catalysts in selective oxidation of propane to acrylic acid were investigated. The results show that the preferred drying method is the rotavapor method, which favors the formation of an effective crystal phase and suppresses the formation of impurity phases. The preferred calcination atmosphere is an Ar atmosphere. The MoVTeNb mixed metal oxide catalysts can be obtained by solution method after heat-treatment at 600°C in an Ar atmosphere, via a rotavapor with a warm water bath at 60°C, and a pH value of 4.0. The catalyst with a MoVTeNb molar ratio of 1.0:0.3:0.23:0.12 is the most effective and extremely active.

Nanostructured Mg-3Ni-2MnO 2 was synthesized by ball milling elemental powders of Mg, Ni and MnO 2 in hydrogen atmosphere. The microstructures of the powder prepared at different milling time were analyzed by X-ray diffractometry(XRD), scanning electron microscopy(SEM) and high resolution electron microscopy(HREM). The milling time is the most key parameter impacting on the grain size and the microstructure of material. With prolonging the milling time, particle size becomes smaller and smaller. But after the ball milling time reaches about 20 h, reduction of grain size becomes slowly. When the milling time is more than 50 h, nanocrystalline fully forms. When the milling time is more than 80 h, there are more amorphous phases in materials. The average particle diameter of material is about 1 μm and the grain size is 10–30 nm.

The effects of chemical composition and preparation conditions, especially calcination atmosphere and water content on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid were investigated. Among the catalysts studied, Mo1.0V0.3Te0.23Nb0.12Ox catalyst calcined in inert atmosphere at 600 °C shows the best performance in terms of propane conversion and selectivity to acrylic acid. The results reveal that proper chemical composition, calcination atmosphere and water content affect greatly the catalysts in many ways including structure, chemical composition, which are related to their catalytic performances; and 51.0% propane conversion and 30.5% one-pass yield to acrylic acid can be achieved at the same time.