This work demonstrates a highly efficient method for large-scale synthesis of elongated BaTiO 3 nanowires via a novel stirring hydrothermal process. Compared with conventional hydrothermal reaction , one-dimensional (1D) lead-free BaTiO 3 nanowires can be realized at an even lower temperature with a shorter dwelling time. Results suggest that the mechanical force-driven stirring process improved the diffusion and surface reaction rate of BaTiO 3 nanocrystal growth in the solution phase, apparently, leading to the growth of the BaTiO 3 nanowires via an oriented attachment mechanism. Meanwhile, to the best of our knowledge, this method is also the first reported protocol which is capable to grow elongated BaTiO 3 nanowires with length up to tens of micrometers. This research outcome provides a promising option for low cost, high-throughput fabrication of 1D nanostructure in respect of mass-manufacturing.
The molten salt electro-deoxidation, i.e. the FFC (Fray-Farthing-Chen) process, demonstrates considerable potential for the synthesis of tantalum powder. However, its practical application is hindered by the long electrolysis duration. This study proposes an accelerated electro-deoxidation process in molten Na 3 AlF 6 -AlF 3 salts for preparing ultrafine Ta powder, which achieves a sequential cathode phase transformation from Ta 2 O 5 through intermediate NaTaO 3 to Ta. NaTaO 3 is formed through in situ interfacial reactions between Ta 2 O 5 and the electrolyte. We demonstrate for the first time that the growth of the FFC-type intermediate is driven by nanoparticle assembly and oriented attachment mechanism. This growth mechanism is influenced by the structure of the electrolyte/particle interface. By constructing a novel hierarchical pore structure Ta 2 O 5 cathode with optimized interfaces, we facilitated a microstructurally controllable transformation of Ta 2 O 5 to fine NaTaO 3 , thereby effectively mitigating the elongation of oxygen ions solid diffusion pathway induced by intermediate coarsening. In the case of self-assembled NaTaO 3 , the weak bonding between the nanoparticles also favors the kinetics of their subsequent decomposition into Ta. This approach has been shown to enable the complete reduction of 1 g of Ta 2 O 5 within only 1 h, demonstrating a significant enhancement in process efficiency. The resulting Ta powder exhibits uniform monodisperse morphology and good capacitive behavior in Na 2 SO 4 electrolyte solution. The present study may now guide the way towards establishing the electrochemical route for the efficient preparation of many other refractory powders materials.
Jiajun Ma,Zongwei Guo,Shengtao Dai,Yannong Liu,Huiru Hu,Peikun Li,Lin Jin,Yuhui Ao
Inducing highly oriented 2D nanosheets to create a mussel-inspired interface phase on the carbon fiber (CF) surface to enhance its composites’ strength and toughness has become a great challenge. In this study, a novel coating was synthesized to induce the graphene oxide (GO) oriented distributed on the CF surface while constructing a biomimetic "Brick-and-Mortar" structural interface phase, which simultaneously promoted the strength and toughness of CF composites . Acting as a sizing agent, di-pyrene terminated PEG (py-PEG-py) facilitates abundant π-π* stacking interactions, and enables flexible chain segment motion during interface fracture of composites, as well as effectively improving the toughness of composites. Eventually, the formation of a superior mechanism on the CF surface results in remarkable properties for composites, including an interfacial shear strength (IFSS) of 99.3 MPa, interlaminar shear strength of 93.2 MPa, and flexural strength of 1430 MPa. The tensile strength and toughness increased to 1777 MPa and 45.0 MJm −3 , respectively. Simultaneously, the continuous thermal conduction pathway produced by the oriented attachment of GO on the CF surface increased in-plane thermal conductivity . The reinforcing mechanisms of the unique mussel-inspired coating were systematically investigated. This work opens up an effective and scalability avenue for obtaining high-performance CF composites.
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