Effects of Al2O3 and Ni as the additives on the sinterability, microstructure and mechanical properties were systematic studied. The experimental results show that only a relative density about 96.2% of hot-pressing T...
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Effects of Al2O3 and Ni as the additives on the sinterability, microstructure and mechanical properties were systematic studied. The experimental results show that only a relative density about 96.2% of hot-pressing TiB2-30%Al2O3 can be attained due to the plate-like TiB2 particle and its random orientation and excessive Al2O3 grain growth. When sintering temperature is higher than 1 700 ℃, TiB2 grain growth can be found, which obvious improves flexural strength of TiB2 matrix but decreases toughness. It seems that mechanical properties of TiB2-Al2O3 composites are mainly depended on relative density besides grain growth. otherwise, they will be determined by relative density and TiB2 matrix strength together. Anyway, Al2O3 addition can weaken the grain boundary and thus improve the toughness of the materials. A flexural strength of 529 MPa, Vickers hardness of 24.8 GPa and indentation toughness of 4.56 MPa·m1/2 can be achieved inTiB2-30vol% Al2O3.
The performance of composite ceramic armor penetrated by rod projectile was studied by both numerical simulation and *** penetration and damage mechanisms of the projectile-armor after high-speed collision were also o...
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The performance of composite ceramic armor penetrated by rod projectile was studied by both numerical simulation and *** penetration and damage mechanisms of the projectile-armor after high-speed collision were also observed by high-speed *** experimental results showed that the ballistic performance of composite ceramic armor was highly affected by the density,hardness and toughness of bulletproof *** flow stress of the failed bulletproof ceramic is not only related to the pressure but also related to the strain *** phenomenological method based on Bodner-Partom ceramic model was introduced to derive the growth rate of *** simulation results show good agreement with the experimental results.
On the basis of experiments, the ZrO2 grain boundaries are classified into three types: the ''clean'' grain boundaries, the grain boundaries with amorphous phases and the grain boundaries with crystal ...
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On the basis of experiments, the ZrO2 grain boundaries are classified into three types: the ''clean'' grain boundaries, the grain boundaries with amorphous phases and the grain boundaries with crystal phases. The structure and property of the three types of grain boundaries were analyzed from the aspects of microstructure and lattice defects, and the conductivity of the crystal grain boundary phases was calculated with the effective-medium theory to be as three times higher as that of the matrix, an idea of further enhancing the ionic conduction of ZrO2 by modifying grain boundaries was thus proposed. The effect of the ZrO2 grain boundaries on the EMF of the oxygen sensor was discussed with simplified models.
The uncontrollable formation of Li dendrites has become the biggest obstacle to the practical application of Li-metal anodes in high-energy rechargeable Li batteries. Herein, a unique LiF interlayer woven by millimete...
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The uncontrollable formation of Li dendrites has become the biggest obstacle to the practical application of Li-metal anodes in high-energy rechargeable Li batteries. Herein, a unique LiF interlayer woven by millimeter-level, single-crystal and serrated LiF nanofibers（NFs） was designed to enable dendrite-free and highly efficient Li-metal deposition. This high-conductivity Li F interlayer can increase the Li+transference number and induce the formation of 'Li F–NFs-rich' solid–electrolyte interface（SEI）. In the 'Li F–NFs-rich'SEI, the ultra-long Li F nanofibers provide a continuously interfacial Li+transport path. Moreover, the formed Li–LiF interface between Li-metal and SEI film renders low Li nucleation and high Li+migration energy barriers, leading to uniform Li plating and stripping processes. As a result, steady charge–discharge in a Li//Li symmetrical cell for 1600 h under 4 m Ah cm-2and 400 stable cycles under a high area capacity of 5.65 mAh cm-2in a high-loading Li//rGO–S cell at 17.9 mA cm-2could be achieved. The free-standing LiF –NFs interlayer exhibits superior advantages for commercial Li batteries and displays significant potential for expanding the applications in solid Li batteries.
The effects of activated sintering technology of H2 atmosphere sintering on the microstructure and properties of W-15Cu alloy using ultrafine W-15Cu composite powder fabricated by spray drying calcining-continuous red...
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The effects of activated sintering technology of H2 atmosphere sintering on the microstructure and properties of W-15Cu alloy using ultrafine W-15Cu composite powder fabricated by spray drying calcining-continuous reduction technology were *** experimental results showed that W-15Cu alloy,consolidated by activated sintering technology of H2 atmosphere sintering for 1 h at 1300 ℃,with 98.5 % relative density,transverse rupture strength 1218 MPa,Vickers hardness HV0.5 378,average grain size about 1.2 μm and thermal conductivity 192 W/m·K,was *** comparison to the normal sintering process,activated sintering process to W-15Cu alloy could be achieved at lower sintering ***,better properties in activated sintered compacts were obtained,and activated sintering process resulted in finer microstructure and excellent properties.
Due to the high theoretical capacity and energy density,lithium-sulfur(Li-S)batteries have good commercial ***,shuttle effect of soluble lithium polysulfides(LiPSs)formed by sulfur reduction has severely limited the f...
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Due to the high theoretical capacity and energy density,lithium-sulfur(Li-S)batteries have good commercial ***,shuttle effect of soluble lithium polysulfides(LiPSs)formed by sulfur reduction has severely limited the further development of Li-S *** this work,the two-dimensional(2D)MXene-metal-organic framework(MOF)(Ti_(3)C_(2)T_(x)-CoBDC(BDC:1,4-benzenedicarboxylate))heterostructures were employed to modify the separator to inhibit the shuttle effect and facilitate the conversion of the soluble ***,a bottom-up synthesis strategy was adopted to synthesize the 2D MXene-MOF heterogeneous layered *** high specific surface area,in which the catalytic metal atoms not only restrain the shuttle effect of polysulfides but also exhibit excellent redox electrocatalytic *** cell with Ti_(3)C_(2)T_(x)-CoBDC@PP(PP:polypropylene)separator has a high initial capacity of 1255 mAh·g^(−1)at 0.5 *** the current density is 2 C,the battery has a capacity retention rate of 94.4%after 600 cycles,with the fading rate of only 0.01%per ***,with a sulfur loading of 7.5 mg·cm^(−2),the battery shows the discharge capacity of 1096 mAh·g^(−1)at 0.2 C and exhibits excellent cycling *** work offers novel insights into the application of MOF and MXene heterostructures in Li-S batteries.
Surface passivation is a common method to improve the resistance of thermal degradation of nitride ***,such a surface passivation generally needs extra processes and decreases the photoluminescence property of the ***...
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Surface passivation is a common method to improve the resistance of thermal degradation of nitride ***,such a surface passivation generally needs extra processes and decreases the photoluminescence property of the *** this work,both the thermal stability and photoluminescence property of a red phosphor Sr_(2)Si_(5)N_(8):Eu are improved through the addition of *** influence of B on the crystal structure and the valence state of active ions was analyzed by experimental ***-principles calculations were applied to analyze the formation energy of N vacancies,which influence the resistance of thermal ***,combining with experimental characterization and calculations,the enhancing mechanism of thermal stability and photoluminescence by B was studied.
作者：
Shuailei LiuJinping LiuSchool of Chemistry
Chemical Engineering and Life ScienceState Key Laboratory of Advanced Technology for Materials Synthesis and ProcessingWuhan University of TechnologyWuhan 430070China
A highlight on reshaping aqueous electrolyte solvation structure for highenergy batteries is ***,the recent key design routes for regulating solvation structure to widen electrochemical stability window(ESW)of aqueous...
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A highlight on reshaping aqueous electrolyte solvation structure for highenergy batteries is ***,the recent key design routes for regulating solvation structure to widen electrochemical stability window(ESW)of aqueous electrolyte are briefly ***,the groundbreaking work of Wang et *** reshaping electrolyte structure using urea as the diluent is ***,the significance of Wang's work is highlighted.
Because of both ozone gas and ozone solution are instable which limits the application of ozone, to solve the storage problem, it is necessary to find a kind ofideal ozone carrier which can combine ozone as an ＂ozoni...
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Because of both ozone gas and ozone solution are instable which limits the application of ozone, to solve the storage problem, it is necessary to find a kind ofideal ozone carrier which can combine ozone as an ＂ozonic compound＂ in which the bond strength between ozone and carrier should not be too high or too low, to appropriately release ozone from the ozonic compound. Combining Criegee’s three-step reaction mechanism of ozone and olefins, the charge, covalent bond levels and energy levels of ozone, ethylene, butadiene and their ozonic compounds were calculated by the first-principles calculation method based on density functional theory methods. The stability of the ozonide, or the bond strength between ozone and ions of carrier were controlled felicitously to release ozone from the ozonide with proper velocity. Ozone antimicrobial was composed on the above principle. It can be used conveniently, especially for common families.
Garnet-type solid-state electrolytes(SSEs)are a remarkable Li-ion electrolyte for the realization of next-generation all-solid-state lithium batteries due to their excellent stability against Li metal as well as high ...
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Garnet-type solid-state electrolytes(SSEs)are a remarkable Li-ion electrolyte for the realization of next-generation all-solid-state lithium batteries due to their excellent stability against Li metal as well as high ionic conductivities at room ***,garnet electrolytes always contain undesired and hardly removable Li_(2)CO_(3) contaminations that have persistently large resistance and unstable interface contact with Li *** is a critical bottleneck for the practical application of garnet ***,we design a novel strategy to completely root out Li_(2)CO_(3) both inside and on the surface of *** is achieved by a so-called double replacement reaction between Li_(2)CO_(3) and SiO_(2) during one-step hot press process for garnet electrolyte *** leads to in-situ transformation of LixSiOy(LSO)mostly locating around the grain boundaries of *** to the higher ion conductivity and better electrochemistry stability of LSO than Li_(2)CO_(3),the modified garnet electrolyte shows much improved electrochemical ***,the wettability between modified garnet electrolyte and lithium metals was significantly enhanced in the absence of surface Li_(2)CO_(3).As a proof of concept,an assembled Li symmetric cell with modified garnet electrolyte displays a high critical current density(CCD)of 0.7 mA cm^(-2)and a low interfacial impedance(5Ωcm^(2))at 25℃.These results indicate that the upcycling of Li_(2)CO_(3)is a promising strategy to well-address the degradation and interfacial issue associated with garnet electrolytes.
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