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Alumina (Al2O3) microfiltration membranes with holey interior structure exhibit the combined desirable properties of both superior permeability and good retention performance. These membranes are purposely made to consist of a holey intermediate layer with a thickness in the range 12.9‐15.5 μm and a top filtration layer of very thin thickness in the range 1.8‐2.8 μm, fabricated by cosintering with sacrificial carbon (C) particles. The holey structure in the intermediate layer, which can be well controlled by regulating the amount of C particles added to Al2O3 particles, contains plenty of holes of 1‐5 μm in size, thereby possessing much reduced water flow resistance. The thin top filtration layer, which contains uniformly distributed nanopores of 90‐100 nm in size, functions as the selective layer, thereby ensuring a good retention performance. At the C particle content of 30 wt. %, the Al2O3 membrane with holey interior structure demonstrates a super‐high pure water flux (3358 Lm‐2h‐1), which is almost twice that of the membrane without holey interior structure (1697 Lm‐2h‐1), while the mechanical strength and retention performance are well maintained. [ABSTRACT FROM AUTHOR]

In this work, we systematically studied the effects of powder characteristics (B 4 C, TiC and Si powders) on the existential form of toughening phases (SiC and TiB 2) as well as the overall microstructure and properties of B 4 C–TiB 2 –SiC composites fabricated by reactive hot pressing. The particle size of the TiC powder plays a largely determining role in the development of novel toughening phases, the TiB 2 –SiC composite structure, that are formed in the B 4 C matrix, while the Si particle size affects the agglomerate level of the SiC phase. The TiB 2 –SiC composite structure and SiC agglomerates enhance the fracture toughness, but decrease the flexural strength. Both the microstructure and mechanical properties of B 4 C–TiB 2 –SiC composites can be effectively tuned by regulating the combinations of the particle sizes of the starting powders. The B 4 C–TiB 2 –SiC composites demonstrate flexural strength, fracture toughness and Vickers hardness in the respective range of 567–632 MPa, 5.11–6.38 MPa m1/2, and 34.8–35.6 GPa. [ABSTRACT FROM AUTHOR]

We have synthesized heat-treated PAN/MoO2/MoS2 (PMOS) ternary structure nanofibers by facile solvothermal approach and in-situ conversion reaction. At discharge current density of 1 A/g, the synthesized hierarchical flexible fibers exhibit high specific capacitance of 439.8 F/g. A lightweight and small asymmetric supercapacitor device based on heat-treated PMOS nanofibers//active carbon (AC) delivers a ultrahigh energy density of 46 Wh/kg at power density of 2246.9 W/kg, and long-term capacity retention of about 98.9% after 2000 cycles. Remarkably, the solid-state asymmetric supercapacitor device could light up a LED belt, and no significant change in the brightness and duration when the device bends into a ring, indicating that the material has perfect flexibility and stability. These encouraging findings indicate that the heat-treated PMOS composite electrodes may have a promising potential application for advanced energy storage devices in modern electronic industries. [ABSTRACT FROM AUTHOR]

Abstract We studied the effects of particle size of raw materials (B 4 C, TiC and Si powders) on the characteristics of both TiB 2 –SiC composite powders and ceramics. Results show that the size of B 4 C and Si particles hardly affects the size of TiB 2 and SiC particles because B 4 C is decomposed and consumed during the formation of TiB 2 , and Si is melted during the formation of SiC. The size of SiC particles is within the nano and submicron scale. However, the size of TiC particles determines the sizes of TiB 2 particles and TiB 2 grains in the composite ceramics because TiC particles serve as templates to form TiB 2 particles. Consequently, the microstructure and mechanical properties of the TiB 2 –SiC composite ceramics are affected. The TiB 2 –SiC composites fabricated using nano-sized TiC powder possess smaller grain size, better dispersibility and more reasonable crack propagation path, thereby obtaining the optimal mechanical properties (Vickers hardness of 30.2 GPa, flexural strength of 732 MPa and fracture toughness of 7.37 MPa m1/2). [ABSTRACT FROM AUTHOR]

Dense ultrafine-grained B 4 C ceramics with superhigh hardness and outstanding fracture toughness were fabricated via spark plasma sintering at 1700 °C and 80 MPa. This process used the ultrafine B 4 C powder prepared by high-energy ball milling as starting powder. During sintering, densification began earlier at 1050 °C and the maximum densification rate appeared earlier at 1500 °C under the influence of high pressure and high sintering activity of the powder. The B 4 C ceramics possessed ultrafine grains, with average grain size of 370 nm, which contributed to the superhigh hardness. Many small B 4 C grains with size of less than 200 nm were individually dispersed among large B 4 C grains or accumulated to form congregated areas. The small grains induced crack deflection, particle pullout and crack bridging, thereby enhancing the toughness of the ceramics. The relative density, Vickers hardness and fracture toughness of the B 4 C ceramics reached 99.4 ± 0.49%, 41.1 ± 0.9 GPa and 4.57 ± 0.12 MPa m 1/2 , respectively. [ABSTRACT FROM AUTHOR]

Dense and fine-grained boron carbide (B 4 C) ceramics were fabricated via high-pressure hot pressing (100 MPa) using powders, which are prepared by high-energy ball milling. These powders were sintered at a low temperature (1800 °C) without any sintering aid. The dense and fine-grained B 4 C ceramics demonstrate super high hardness, outstanding fracture toughness and modern flexure strength. The milled powders were characterised by disordered crystal structure and ultrafine particle size that ranges from a few nanometres to a few hundred nanometres. The combined contributions of high pressure and the characteristic of the milled powders guaranteed that the dense fine-grained microstructure was achieved at only 1800 °C. The grain size distribution of the ceramics was inhomogeneous and ranged from 70 nm to 1.6 µm. However, the average grain size was fine at only 430 nm, which partially contributed to the super high hardness of the B 4 C ceramics. The locally concentrated areas of the small grains changed the fracture mode of the B 4 C ceramics from the complete transgranular fracture to a mixture of transgranular and intergranular fractures, thereby enhancing the toughness of the B 4 C ceramics. The relative density, Vickers hardness, flexure strength and fracture toughness of the obtained B 4 C ceramics reached up to 99.5%, 41.3 GPa, 564 MPa and 4.41 MPa m 1/2 , respectively. [ABSTRACT FROM AUTHOR]