Search

Ti(C,N)-TiB2 cermets were fabricated from Ti(C,N), TiB2, Co and WC powder mixtures via a vacuum hot pressing process. The influence of TiB2 content on their microstructures and mechanical properties was investigated. As a result of the elevated TiB2 contents, two types of core-rim microstructures were present in the Ti(C,N)-TiB2 cermets, and remarkably improved mechanical properties were achieved. With the increase of TiB2 content, the flexural strength, fracture toughness and hardness of the Ti(C,N)-TiB2 cermets first increased, and then decreased, while their relative density consistently decreased. Attributed to an integration of the intergranular and intrangranular fracture behaviors, the Ti(C,N)-TiB2 cermets with 20 wt% TiB2 content exhibited the best overall properties with the relative density, hardness, fracture toughness and flexural strength at 99.3%, 1 995 H V, 7.92 MPa·m1/2 and 1 114 MPa, respectively. The underlying mechanism for their enhanced properties was studied in detail. [ABSTRACT FROM AUTHOR]

ZrO2‐whisker‐reinforced Ti(C,N)‐based cermets were designed and prepared via a vacuum hot‐pressing process. The ZrO2 whisker characteristics and the phase, microstructure and mechanical properties of the cermets were investigated, and the relevant toughening mechanisms were examined. The results indicate that the ZrO2 whiskers retain their morphology and significantly improve the mechanical properties of the cermets. The relative density and hardness decreased slightly with increasing ZrO2 whisker content. At a whisker content of 7.5 wt.%, the fracture toughness and flexural strength reached their maximum values of 7.825 MPa·m1/2 and 1094 MPa, respectively. This enhancement in the mechanical properties is due to stronger bonding between the interfaces through dimples, tearing ridges and whisker pull‐out, in addition to the inhibition of crack propagation via crack deflection, crack branching and crack bridging. [ABSTRACT FROM AUTHOR]

A new porous material, alveolate Cu2−xSe microsheets, was synthesized through a simple one-step solvothermal process. The surface morphology and microstructure of the as-prepared Cu2−xSe were characterized by various techniques. It was found that the as-synthesized Cu2−xSe has hierarchical porosity composed of mesopores and macropores, and rich active surfaces of {111} facets. A noteworthy visible-light-responsive photocatalytic discoloration of Rhodamine B was observed for the as-developed alveolate Cu2−xSe microsheets. The superior photocatalytic properties demonstrated by the as-synthesized Cu2−xSe are mainly attributed to the highly accessible active surfaces of the {111} facets and the wider light absorption range resulting from its narrower band gap. [ABSTRACT FROM AUTHOR]

Developing high-capacity anodes is of great importance for the advancement of sodium ion batteries. In this work, we report a powerful combined method of plasma enhanced chemical vapor deposition–electrodeposition (PECVD–ED) to construct high-quality vertical graphene/MoO2 (VG/MoO2) core/shell arrays. The conductive MoO2 (n-type semiconductor) shell is uniformly electrodeposited on the VG core to form a binder-free integrated electrode. Compared with carbon fibre cloth-supported MoO2 film (CFC/MoO2), the obtained VG/MoO2 core/shell arrays display a higher surface area, better mechanical stability and improved electrical conductivity. Due to these positive advantages, the VG/MoO2 arrays show enhanced sodium ion storage performance with a reversible capacity of 678 mA h g−1 (vs. 542 mA h g−1 for CFC/MoO2) at the current density of 100 mA g−1, and a stable cycling life with a capacity retention of 81.7% (vs. 62.1% for CFC/MoO2) after 500 cycles. Our results provide a new route for the synthesis of high-capacity anodes for sodium ion batteries. [ABSTRACT FROM AUTHOR]

Recently, stripe antiferromagnetic spin fluctuations have been observed in SrCo2As2, which are similar to those found in AFe2As2 superconductors. It is interesting to tune the magnetic properties of this compound to induce superconductivity by chemical doping or applied pressure. Here we present careful chemical doping studies on SrCo2As2 by doping the element La on the Sr sites. We found that a dramatic alteration of the magnetic behavior (from paramagnetism to ferromagnetism) was induced by the incorporation of traces of La (2.5%). The results show that ferromagnetic order is preferred over A-type AFM or stripe-type AFM order when SrCo2As2 is electron-doped. On this basis, in order to regulate its magnetic ground state with the aim of inducing superconductivity, hole-doping may be superior to electron-doping. Furthermore, an unusual magnetic phase diagram between SrCo2As2 and LaCo2As2 is also presented in this work. [ABSTRACT FROM AUTHOR]

Lithium ions batteries (LIBs) with high power/energy densities largely rely on the innovation of electrode materials. Herein, for the first time, we rationally construct novel titanium niobium oxide (Ti2Nb10O29, TNO) nanospheres with a three-dimensional porous structure consisting of cross-linked nanoparticles by a simple solvothermal method combined with heat treatment. Compared to bulk TNO microrods, the obtained TNO nanospheres show a larger specific surface area and richer/shorter transfer channels for ions/electrons. Owing to these advantages, the TNO nanosphere electrode exhibits noticeable exceptional electrochemical performance with superior high-rate capability (241 mA h g−1 at 10C, and 208 mA h g−1 at 20C) and ultra-long life with a capacity of 215 mA h g−1 after 500 cycles at 10C, much better than the TNO microrod counterparts. Our findings may pave a new way for the design/fabrication of the state-of-the-art electrodes for electrochemical energy storage. [ABSTRACT FROM AUTHOR]