Additive manufacturing(AM)technology has emerged as a viable solution for manufacturing complexshaped WC−Co cemented carbide products,thereby expanding their applications in industries such as resource mining,equipmen...Additive manufacturing(AM)technology has emerged as a viable solution for manufacturing complexshaped WC−Co cemented carbide products,thereby expanding their applications in industries such as resource mining,equipment manufacturing,and electronic information.This review provides a comprehensive summary of the progress of AM technology in WC−Co cemented carbides.The fundamental principles and classification of AM techniques are introduced,followed by a categorization and evaluation of the AM techniques for WC−Co cemented carbides.These techniques are classified as either direct AM technology(DAM)or indirect AM technology(IDAM),depending on their inclusion of post-processes like de-binding and sintering.Through an analysis of microstructure features,the most suitable AM route for WC−Co cemented carbide products with controllable microstructure is identified as the indirect AM technology,such as binder jet printing(BJP),which integrates AM with conventional powder metallurgy.展开更多
The good combination of mechanical and wear properties for cemented carbides is crucial.In this work,the wear behavior of functionally graded cemented carbide(FGCC)and non-graded cemented carbide(CC),with CoNiFeCr mul...The good combination of mechanical and wear properties for cemented carbides is crucial.In this work,the wear behavior of functionally graded cemented carbide(FGCC)and non-graded cemented carbide(CC),with CoNiFeCr multi-principal-element alloy(MPEA)binder,has been investigated by performing sliding wear tests and composition characterization.The results showed that compared with CC,FGCC had higher hardness,stronger fracture toughness,better wear performance,and similar TRS.FGCCs exhibited lower wear rates(3.44×10^(−7)–6.95×10^(−6)mm^(3)/(N m))and coefficients of friction(COFs)(0.27–0.39)than CCs from RT to 600℃due to mitigation of multiple risks caused by binder removal,fragmentation and pull-out of WC grains,high-temperature oxidation and softening.In the low-temperature wear stage,the MPEA binder underwent dynamic recrystallization(DRX)and twinning deformation before removing from the surface.The binder removal caused dislocation pile-ups and stacking faults(SFs)to form under high stress,resulting in fragmentation and pull-out of WC grains.The low-temperature wear was dominated by abrasive wear and adhesive wear,with a low wear rate and a high and unstable COF.In the high-temperature wear stage,initial pitting oxidation of WC grains generated many subgrain boundaries,reducing heat transfer and exacerbating oxidation,resulting in an oxide layer enriched with WO3,Mx Oy,and MWO4.High-temperature wear was dominated by oxidation wear and high-temperature softening,with a high wear rate and a low and smooth COF.The results from the present study do not only provide theoretical guidance for an understanding of the antiwear mechanism of WC-CoNiFeCr,but also a new approach for the preparation of cemented carbides with high wear resistance.展开更多
The effects of prior austenite and primary carbides on the mechanical properties of a novel 2.5 GPa grade steel were investigated by treating at various solid-solution temperatures.The ultimate tensile strength and Ch...The effects of prior austenite and primary carbides on the mechanical properties of a novel 2.5 GPa grade steel were investigated by treating at various solid-solution temperatures.The ultimate tensile strength and Charpy U-notch impact energy initially increased and subsequently decreased as the solid-solution temperature rose,while the yield strength consistently decreased.The size of prior austenite grain and martensite block always increased with rising the solid-solution temperature,and austenite grain growth activation energy is 274,969 J/mol.The growth of prior austenite was restricted by primary carbides M6C and MC.The dissolution of the primary carbides not only enhanced solid-solution strengthening and secondary hardening effects but also increased the volume fraction of retained austenite.The increase in the ultimate tensile strength and Charpy U-notch impact energy was primarily attributed to the dissolution of the primary carbides M6C and MC,while the decrease was due to the increase in the size of prior austenite grain and martensite block.Exceptional combination of strength,ductility and toughness with ultimate tensile strength of 2511 MPa,yield strength of 1920 MPa,elongation of 9.5%,reduction of area of 41%and Charpy U-notch impact energy of 19.5 J was obtained when experimental steel was solid-solution treated at 1020℃.展开更多
Ti(C,N)-Mo_(2)C-Ni cermet as alternative materials was explored for use in alkaline conditions,replacing the WC-Co cemented carbides,since Co is classified as a potentially carcinogenic substance and there is potentia...Ti(C,N)-Mo_(2)C-Ni cermet as alternative materials was explored for use in alkaline conditions,replacing the WC-Co cemented carbides,since Co is classified as a potentially carcinogenic substance and there is potential hazard of“hard metal disease”under the exposure to cobalt dust.The changes in microstructure,corrosion rate and volumetric loss rate of the two materials were compared under electrochemical corrosion and erosion-corrosion in alkaline environment.The results demonstrates that Ti(C,N)-Mo_(2)C-Ni cermet undergoes passivation when exposed to electrochemical corrosion of NaOH solution,resulting in a significant increase in oxygen content on the corroded surface.The corrosion rate of cermet is approximately one order of magnitude lower than that of the cemented carbide.Under the erosion-corrosion of an alkaline sand-water mixture,both the cermet and cemented carbide experience a gradual increase in volumetric loss rate with prolonging the erosion time.During erosion,the rim phase in cermet is fragile,so cracks easily penetrate it while the core phase remains intact.The medium-grained cemented carbide commonly demonstrates transgranular fracture mode,while in the fine-grained cemented carbide,cracks tend to propagate along phase boundaries.The erosive wear and damage caused by sand particles play a predominant role in the erosion-corrosion process of alkaline sand-water mixtures.This process represents an accelerated destructive phenomenon influenced and intensified by the combined effects of corrosion and erosion.It is confirmed that using cermet as an alternative anti-wear material to cemented carbides is feasible under alkaline conditions,and even better.展开更多
The high-temperature dissolution behavior of primary carbides in samples taken from GCr15 continuous-casting bloom was observed in-situ by confocal laser scanning microscopy.Equations were fitted to the dissolution ki...The high-temperature dissolution behavior of primary carbides in samples taken from GCr15 continuous-casting bloom was observed in-situ by confocal laser scanning microscopy.Equations were fitted to the dissolution kinetics of primary carbides during either heating or soaking.Dissolution of carbides proceeded in three stages(fast→slow→faster)as either temperature or holding time was increased.During the heating process and during the first and third stages of the soaking process,the original size of the carbides determined the steepness of the slope,but during the middle(“slow”)stage of the soaking process,the slope remained zero.The initial size of the carbides varied greatly,but their final dissolution temperature fell within the narrow range of 1210-1235℃,and the holding time remained within 50 min.Fractal analysis was used to study the morphological characteristics of small and medium-sized carbides during the dissolution process.According to changes in the fractal dimension before and after soaking,the carbides tended to evolve towards a more regular morphology.展开更多
Surface icing and fouling pose a substantial threat to marine facilities.Herein,anti-icing coating composites(F/S-WC-n%/F)with high photo-thermal conversion efficiencies were prepared by spraying a small amount of sup...Surface icing and fouling pose a substantial threat to marine facilities.Herein,anti-icing coating composites(F/S-WC-n%/F)with high photo-thermal conversion efficiencies were prepared by spraying a small amount of super-hydrophobic tungsten carbide on fluoro-olefin vinyl ether copolymer(FEVE)at a specific pressure.The photo-thermal properties of the coatings provide them with ice melting and sterilization effects.The delayed icing time of F/S-WC-5%/F is 571 s,with the ice-covered-surface temperature increasing to 42°C after exposure to simulated sunlight.Heat transfer modelling calculations show that icing needs to overcome high Gibbs free energy on F/S-WC-5%/F.Quantum chemistry fundamentally reveals a weak thermodynamic effect of water nucleation on F/S-WC-5%/F,indicating that the icing process requires a high degree of sub-cooling,resulting in delayed icing.In addition,F/S-WC-5%/F can resist different types of fouling and exhibit sterilization activity.Using F/S-WC-5%/F,Escherichia coli germs are killed via heat-induced morphological rupture under a solar simulator.Owing to its excellent environmental versatility,sustainability,mechanical durability and material adaptability,F/S-WC-5%/F is a promising anti-icing and anti-fouling candidate for various practical applications,even in harsh environments.展开更多
To address the increasing demand for massive data storage and processing,brain-inspired neuromorphic comput-ing systems based on artificial synaptic devices have been actively developed in recent years.Among the vario...To address the increasing demand for massive data storage and processing,brain-inspired neuromorphic comput-ing systems based on artificial synaptic devices have been actively developed in recent years.Among the various materials inves-tigated for the fabrication of synaptic devices,silicon carbide(SiC)has emerged as a preferred choices due to its high electron mobility,superior thermal conductivity,and excellent thermal stability,which exhibits promising potential for neuromorphic applications in harsh environments.In this review,the recent progress in SiC-based synaptic devices is summarized.Firstly,an in-depth discussion is conducted regarding the categories,working mechanisms,and structural designs of these devices.Subse-quently,several application scenarios for SiC-based synaptic devices are presented.Finally,a few perspectives and directions for their future development are outlined.展开更多
To tackle the common issue of green defects in material extrusion(MEX)additive manufacturing(AM)cemented carbides,warm isostatic pressing(WIP)was introduced to eliminate defects of MEX WC-9Co cemented carbide greens,t...To tackle the common issue of green defects in material extrusion(MEX)additive manufacturing(AM)cemented carbides,warm isostatic pressing(WIP)was introduced to eliminate defects of MEX WC-9Co cemented carbide greens,thereby improving both microstructure uniformity and mechanical properties of sintered bodies.The results indicate that WIP reduces defects in MEX greens,thus decreasing the dimensions and numbers of defects,modifying shapes of pores within sintered bodies,while preserving surface quality and shape characteristics.Compared with WC-9Co prepared via MEX followed by debinding and sintering(DS),the hardness of WC-9Co prepared using MEX-WIP-DS does not change significantly,ranging HV_(30)1494-1508,the transverse rupture strength increases by up to 49.3%,reaching 2998-3514 MPa,and the fracture toughness remains high,ranging 14.8-17.0 MPa·m^(1/2).The mechanical properties surpass comparable cemented carbides fabricated through other AM methods and are comparable to those produced by powder metallurgy.The integration of green WIP into MEX-DS broadens the MEX processing window,and improves the overall mechanical properties of MEX AM WC-Co cemented carbides.展开更多
The influence of graphene platelets(GPLs)on the WC grain size of WC-Co-GPLs cemented carbide prepared by low-pressure sintering was investigated.The role of GPLs in refining WC grains was explored by characterizing gr...The influence of graphene platelets(GPLs)on the WC grain size of WC-Co-GPLs cemented carbide prepared by low-pressure sintering was investigated.The role of GPLs in refining WC grains was explored by characterizing grain size and phase distribution.Results show that the addition of GPLs leads to significant grain refinement of WC and the more uniform distribution of WC grain size.When the content of GPLs is 0.10wt%,the average WC grain size in the cemented carbide is 0.39μm,which is 32%lower than that in WC-Co.However,the shape of WC grains is almost unaffected,while the mean free path of Co decreases.The grain refinement of WC is attributed to the homogeneous distribution of GPLs between WC/WC and WC/Co grain boundaries,which hinders the solution and precipitation process of WC in liquid phase Co,as well as the migration and growth of WC grains.Additionally,GPLs can serve as heat transfer plates in materials to improve cooling efficiency,thus inhibiting the growth of WC grain.展开更多
Tungsten carbide-based(WC-based)cemented carbides are widely recognized as high-performance tool materials.Traditionally,single metals such as cobalt(Co)or nickel(Ni)serve as the binder phase,providing toughness and s...Tungsten carbide-based(WC-based)cemented carbides are widely recognized as high-performance tool materials.Traditionally,single metals such as cobalt(Co)or nickel(Ni)serve as the binder phase,providing toughness and structural integrity.Replacing this phase with high-entropy alloys(HEAs)offers a promising approach to enhancing mechanical properties and addressing sustainability challenges.However,the complex multi-element composition of HEAs complicates conventional experimental design,making it difficult to explore the vast compositional space efficiently.Traditional trial-and-error methods are time-consuming,resource-intensive,and often ineffective in identifying optimal compositions.In contrast,artificial intelligence(AI)-driven approaches enable rapid screening and optimization of alloy compositions,significantly improving predictive accuracy and interpretability.Feature selection techniques were employed to identify key alloying elements influencing hardness,toughness,and wear resistance.To enhance model interpretability,explainable artificial intelligence(XAI)techniques—SHapley Additive exPlanations(SHAP)and Local Interpretable Model-agnostic Explanations(LIME)—were applied to quantify the contributions of individual elements and uncover complex elemental interactions.Furthermore,a high-throughput machine learning(ML)–driven screening approach was implemented to optimize the binder phase composition,facilitating the discovery of HEAs with superiormechanical properties.Experimental validation demonstrated strong agreement between model predictions and measured performance,confirming the reliability of the ML framework.This study underscores the potential of integrating ML and XAI for data-driven materials design,providing a novel strategy for optimizing high-entropy cemented carbides.展开更多
Boron-based fuels,recognized for their high energy density and potential in energetic applications,encounter challenges such as long ignition delays and incomplete combustion,which result in reduced combustion efficie...Boron-based fuels,recognized for their high energy density and potential in energetic applications,encounter challenges such as long ignition delays and incomplete combustion,which result in reduced combustion efficiency and limited performance in aerospace propulsion.In this study,boron carbide(B4C)is investigated as an alternative fuel to pristine boron due to its favorable gas-phase combustion.Both metal oxide(nickel oxide(NiO))and metal fluoride(nickel fluoride(NiF_(2)))are selected as oxidizing modifiers to enhance the reactivity of B4C.A method combining laser ignition with optical diagnostics is employed to investigate the enhancing effects of different oxidizers on the ignition and combustion characteristics of B4C.Both NiO and NiF_(2)can significantly increase the combustion radiation intensity and reduce the time to maximum intensity of B4C.Differential scanning calorimetry,in-situ X-ray diffraction,and Fourier transform infrared spectroscopy were used for simultaneous thermal analysis of the B4C composite powders.Combined thermal analysis showed that the effects of NiO and NiF_(2)on promoting B4C combustion is mainly achieved via the formation of NimBn and the release of a large number of gas products.It is reasonable to speculate that the phase separation at the B2O3/NimBn interface forms new pathways for oxygen diffusion and reaction with the B core.The difference in the combustion mechanism of B4C with NiO and NiF_(2)lies in the gas phase products,i.e.,CO_(2)and BF3,respectively,thus leading to significant differences in their reaction processes.展开更多
Common activations of sulfite(S(Ⅳ))-based advanced oxidation processes(AOPs)utilized metal ions and oxides as catalysts,which are constrained by challenges in catalyst recovery,inadequate stability,and susceptibility...Common activations of sulfite(S(Ⅳ))-based advanced oxidation processes(AOPs)utilized metal ions and oxides as catalysts,which are constrained by challenges in catalyst recovery,inadequate stability,and susceptibility to secondary pollution in application.Calcium sulfite(CaSO_(3)),one of the byproducts of flue gas desulfurization,is of interest in AOPs because of its ability to slowly release S(Ⅳ),low toxicity,and costeffectiveness.Therefore,a heterogenous activator,molybdenum carbide(Mo_(2)C)was selected to stimulate Ca SO3for typical antibiotic elimination.Benefiting from the dissociation form of HSO_(3^(-))from CaSO_(3)and improved electron transfer of Mo_(2)C at pH 6,the simulated target metronidazole(MTZ)can be removed by 85.65%with rate constant of 0.02424 min^(-1)under near-neutral circumstance.The combining determinations of quenching test,electron spin resonance spectrum,and reactive species probe demonstrated singlet oxygen(^(1)O_(2))and sulfate radicals played leading role for MTZ decontamination.Characterization and theoretical calculation suggested the alteration of Mo valence state drove the activation of S(Ⅳ),and revealed that dissolved oxygen promoted the adsorption of HSO_(3^(-))on the surface of Mo_(2)C,then facilitating production of^(1)O_(2).The favorable stability and applicability for Mo_(2)C/CaSO_(3)process indicated an applied prospect in actual pharmaceutical wastewater.展开更多
Photo-Cross-Linkable hydrogel has attracted immense interest in the regeneration of bone repair and regeneration strategies due to its superior biocompatibility and tunable mechanical properties.Recently,Nb was report...Photo-Cross-Linkable hydrogel has attracted immense interest in the regeneration of bone repair and regeneration strategies due to its superior biocompatibility and tunable mechanical properties.Recently,Nb was reported to strongly promote the bone regeneration process via an accelerated osteoblast-modulated alkaline phosphatase activity mechanism.In particular,Nb2C MXenes have drawn widespread attention due to their excellent biocompatibility and ability to induce bone formation.However,the easy agglomeration of Nb2C nanosheets and subsequent low cell endocytosis efficacy greatly suppressed the osteogenesis effect.In this study,a subtractive nanopore-engineered Nb2C MXene was prepared through a microwave combustion method,gelatin methacrylate was used as the carrier hydrogel,and the photo-triggered Porous-Nb2C@GelMA hydrogel was fabricated by a photo-triggered process.The pore-forming strategy not only successfully improved the distribution of Nb2C and formed more homogenous Porous-Nb2C@GelMA hydrogels but also guided bone marrow mesenchymal stem cells(BMSCs)toward osteoblast differentiation.Porous Nb2C provided convenient cellular grasping and endocytosis for BMSCs,which further created a favorable environment for differentiation and osteogenesis.This,in turn,leads to an increase in the expression of osteogenic markers,such as ALP and ARS,as well as osteogenic factors,such as BMP-2,COL-1,OCN,and OPN.Consequently,enhancing the regenerative microenvironment by incorporating porous Nb2C composite hydrogels shows promise for application in bone regeneration.展开更多
Traditional heat treatment methods require a significant amount of time and energy to affect atomic diffusion and enhance the spheroidization process of carbides in bearing steel,while pulsed current can accelerate at...Traditional heat treatment methods require a significant amount of time and energy to affect atomic diffusion and enhance the spheroidization process of carbides in bearing steel,while pulsed current can accelerate atomic diffusion to achieve ultra-fast spheroidization of carbides.However,the understanding of the mechanism by which different pulse current parameters regulate the dissolution behavior of carbides requires a large amount of experimental data to support,which limits the application of pulse current technology in the field of heat treatment.Based on this,quantify the obtained pulse current processing data to create an important dataset that could be applied to machine learning.Through machine learning,the mechanism of mutual influence between carbide regulation and various factors was elucidated,and the optimal spheroidization process parameters were determined.Compared to the 20 h required for traditional heat treatment,the application of pulsed electric current technology achieved ultra-fast spheroidization of GCr15 bearing steel within 90 min.展开更多
As the main use of TBM(tunnel boring machine)cutter ring(DC53 steel)currently is difficult to meet the requirements of high wear resistance and high toughness synchronously in its service environment,a new HWR0 steel ...As the main use of TBM(tunnel boring machine)cutter ring(DC53 steel)currently is difficult to meet the requirements of high wear resistance and high toughness synchronously in its service environment,a new HWR0 steel with 4%Cr-3%V for TBM cutter ring has been developed to control carbides in steel.Precipitation behavior of carbides in HWR0 steel was investigated through theoretical calculation by Thermo-Calc and experimental measurement using scanning electron microscope,energy dispersive spectrometer,electron probe X-ray micro-analyzer,and laser particle size analyzer.The results show that three different carbides are precipitated during cooling.And the as-cast electroslag remelting ingot of HWR0 steel primarily consists of many blocky or strip-like MC distributed along grain boundaries,few chrysanthemum-like M_(6)C concentrated at grain boundary intersections,and a large quantity of fine M_(23)C_(6)and M_(6)C dispersed in the matrix.Compared with DC53 steel,HWR0 steel has more high-hardness carbides MC,which are discontinuously distributed at the grain boundaries,achieving the dual improvement of wear resistance and impact toughness.Cooling rates significantly influence the carbides distribution and grain size.A slower cooling rate exacerbates the segregation of alloying elements,which leads to the localized enrichment of Mo and the subsequent precipitation of M_(6)C carbides at grain boundary intersections.In contrast,faster cooling rate decreases the element segregation,promotes carbide nucleation and limits the space for carbides growth,which results in finer size and distribution of carbides and grains.Higher cooling rates yield a more homogeneous microstructure with uniform MC compositions and promote the preferential formation of M_(6)C carbides along grain boundaries,which enhances the mechanical properties.展开更多
This study introduced a low-temperature thermochemical method for the treatment of EMR in the presence of carbide slag(CS)to achieve an economical and efficient harmless effect.The experimental results indicate that,u...This study introduced a low-temperature thermochemical method for the treatment of EMR in the presence of carbide slag(CS)to achieve an economical and efficient harmless effect.The experimental results indicate that,under suitable conditions,the NH_(4)^(+)and Mn^(2+)contents in EMR decrease notably with the increasing CS content,accompanied by an increase in pH value.Furthermore,the concentration of NH_(4)^(+)in EMR considerably decreases with the increasing liquid-to-solid ratio,eventually stabilizing.Similarly,the pH value first increases and then decreases,ultimately stabilizing.At a CS content of 12%and a liquid-to-solid ratio of 0.7,the leaching concentrations of NH_(4)^(+)and Mn^(2+)in EMR(127.7 mg/kg and 0.15 mg/L,respectively)fall below the standard detection limit(2 mg/L),with the pH measuring 8.26,meeting the conditions outlined in the GB 8978.NH_(4)^(+)is converted to NH_(3),while Mn^(2+)is transformed into solid precipitates such as Mn(OH)_(2),Mn_(2)O_(3),MnO_(2),Ca_(3)Mn_(2)O_(7),and Ca_(2)MnO_(4).The majority of manganese ions exist in trivalent or tetravalent states and remain stable over time.The cost of using CS as a reagent for treating 1 ton of EMR is merely$1.01.The high OH^(-)concentration provided by CS enables the effective removal of NH_(4)^(+)from EMR and the solidification of Mn^(2+)during thermal reactions.展开更多
The direct deoxygenative homo-coupling of benzyl alcohols holds great promise to build up bibenzyl motifs in organic synthesis,yet it remains a grand challenge in selectivity and activity control.Herein,we first disco...The direct deoxygenative homo-coupling of benzyl alcohols holds great promise to build up bibenzyl motifs in organic synthesis,yet it remains a grand challenge in selectivity and activity control.Herein,we first discovered that iron carbide catalysts displayed high efficiency and selectivity in the catalytic deoxygenative homo-coupling of benzyl alcohols into bibenzyls using H_(2)as the reductant.Ir-promoted Fe0@Fe_(5)C_(2)gave the best performance among the investigated catalysts,and a broad scope of substrates with diverse functional groups could be smoothly converted into bibenzyls,with the yield up to 85%.In addition,in the presence of alkenes,three-component coupling reactions between alcohols and alkenes were also for the first time achieved to construct more complex multi-ring molecules.The radical-trapping experiment and FTIR measurements revealed the radical nature of the reaction and the significantly promoted C–O bond activation after carbonization,respectively.This work will provide guidelines for the rational design of efficient and selective catalysts for the alcohol-involved carbon-carbon coupling reactions.展开更多
Silicon carbide(SiC)ceramics are extensively utilized in aerospace,national defense,and petrochemical industries due to their superior physical and chemical properties.The processing of bulk SiC ceramics necessitates ...Silicon carbide(SiC)ceramics are extensively utilized in aerospace,national defense,and petrochemical industries due to their superior physical and chemical properties.The processing of bulk SiC ceramics necessitates precise and efficient grinding techniques to produce components with satisfactory functionality.However,the inherent high hardness and brittleness of SiC ceramics present significant challenges during grinding,leading to severe brittle fracture and tool wear that compromise both surface integrity and production efficiency.Although ductile-regime grinding of SiC ceramics can be achieved by enhancing machine tool accuracy and stiffness while optimizing wheel performance alongside appropriate selection of process parameters,a comprehensive summary of the mechanisms underlying damage evolution during grinding is lacking,and a mature grinding process for SiC ceramics has yet to be developed.To bridge this gap,the sintering technologies,mechanical properties,and microstructures of SiC ceramics were briefly covered.The grinding-induced damage mechanism and low-damage grinding technologies of SiC ceramics were summarized.The fundamental science underlying the ductile deformation and removal mechanisms of brittle solids was emphasized.Additionally,attention was directed towards the critical role of hybrid energy field grinding in minimizing brittle damages and promoting removal efficiency.This review not only elucidates the intrinsic interactions between the work material and abrasives,but also offers valuable insights for optimizing the grinding processes of brittle solids.展开更多
Microelectromechanical system(MEMS)high-temperature pressure sensors are widely used in aerospace,petrochemical industries,automotive electronics,and other fields owing to their advantages of miniaturization,lightweig...Microelectromechanical system(MEMS)high-temperature pressure sensors are widely used in aerospace,petrochemical industries,automotive electronics,and other fields owing to their advantages of miniaturization,lightweight design,simplified signal processing,and high accuracy.In recent years,advances in semiconductor material growth technology and intelligent equipment operation have significantly increased interest in high-temperature pressure sensors based on the third-generation semiconductor silicon carbide(SiC).This review examines the material properties of SiC single crystals and discusses several technologies influencing the performance of SiC pressure sensors,including the piezoresistive effect,ohmic contact,etching processes,and packaging methodologies.Additionally,it explores future research directions in the field.The review highlights the importance of increasing operating temperatures and advancing sensor integration as critical trends for future SiC high-temperature pressure sensor research and applications.展开更多
Tantalum(Ta)alloys have been widely utilized in rocket,air-breathing engines,and airframe applications.However,traditional Ta alloys suffer from insufficient strength at ultra-high temperature,making it challenging to...Tantalum(Ta)alloys have been widely utilized in rocket,air-breathing engines,and airframe applications.However,traditional Ta alloys suffer from insufficient strength at ultra-high temperature,making it challenging to satisfy the design requirements for next-generation aerospace equipment.We report a novel strategy to design Ta alloys with superior mechanical properties by integrating the multi-principal element concept with compositionally complex carbides.By introducing multiple refractory elements and C,the resultant alloys displayed a thermally stable microstructure consisting of two phases.With the increasing C contents,the microstructure evolved from hypoeutectic to eutectic and then to hypereutectic.These varying microstructural characteristics influenced crack blunting and dislocation accumulation behaviors,leading to different softening resistance at 1600℃and plasticity at room temperature.Benefiting from the strengthening effects of solid solution and compositionally complex carbides,these alloys exhibited a high strength of~600 MPa at 1600℃,significantly superior than that of traditional Ta alloys.展开更多
基金supported by Major Science and Technology Projects in Fujian Province,China(No.2023HZ021005)State Key Laboratory of Powder Metallurgy,Central South University,ChinaFujian Key Laboratory of Rare-earth Functional Materials,China。
文摘Additive manufacturing(AM)technology has emerged as a viable solution for manufacturing complexshaped WC−Co cemented carbide products,thereby expanding their applications in industries such as resource mining,equipment manufacturing,and electronic information.This review provides a comprehensive summary of the progress of AM technology in WC−Co cemented carbides.The fundamental principles and classification of AM techniques are introduced,followed by a categorization and evaluation of the AM techniques for WC−Co cemented carbides.These techniques are classified as either direct AM technology(DAM)or indirect AM technology(IDAM),depending on their inclusion of post-processes like de-binding and sintering.Through an analysis of microstructure features,the most suitable AM route for WC−Co cemented carbide products with controllable microstructure is identified as the indirect AM technology,such as binder jet printing(BJP),which integrates AM with conventional powder metallurgy.
基金financially supported by the National Key Research and Development Program of China(No.2021YFB3701800)Special funding support for the Yuelu Mountain National University Science and Technology City“Ranking the Top of the List”Research Project:(Tunnel Boring Machine High-performance Long-life Cutting Tools)the State Key Laboratory of Powder Metallurgy,Central South University,Changsha,China.
文摘The good combination of mechanical and wear properties for cemented carbides is crucial.In this work,the wear behavior of functionally graded cemented carbide(FGCC)and non-graded cemented carbide(CC),with CoNiFeCr multi-principal-element alloy(MPEA)binder,has been investigated by performing sliding wear tests and composition characterization.The results showed that compared with CC,FGCC had higher hardness,stronger fracture toughness,better wear performance,and similar TRS.FGCCs exhibited lower wear rates(3.44×10^(−7)–6.95×10^(−6)mm^(3)/(N m))and coefficients of friction(COFs)(0.27–0.39)than CCs from RT to 600℃due to mitigation of multiple risks caused by binder removal,fragmentation and pull-out of WC grains,high-temperature oxidation and softening.In the low-temperature wear stage,the MPEA binder underwent dynamic recrystallization(DRX)and twinning deformation before removing from the surface.The binder removal caused dislocation pile-ups and stacking faults(SFs)to form under high stress,resulting in fragmentation and pull-out of WC grains.The low-temperature wear was dominated by abrasive wear and adhesive wear,with a low wear rate and a high and unstable COF.In the high-temperature wear stage,initial pitting oxidation of WC grains generated many subgrain boundaries,reducing heat transfer and exacerbating oxidation,resulting in an oxide layer enriched with WO3,Mx Oy,and MWO4.High-temperature wear was dominated by oxidation wear and high-temperature softening,with a high wear rate and a low and smooth COF.The results from the present study do not only provide theoretical guidance for an understanding of the antiwear mechanism of WC-CoNiFeCr,but also a new approach for the preparation of cemented carbides with high wear resistance.
基金supported financially by National Key Research and Development Program of China(No.2022YFB3705200)Heilongjiang Province's Key Technology Project:‘Leading the Charge with Open Competition’(No.2023ZXJ04A02)Youth Program of CISRI Funding under Grant(No.S-23T60190B).
文摘The effects of prior austenite and primary carbides on the mechanical properties of a novel 2.5 GPa grade steel were investigated by treating at various solid-solution temperatures.The ultimate tensile strength and Charpy U-notch impact energy initially increased and subsequently decreased as the solid-solution temperature rose,while the yield strength consistently decreased.The size of prior austenite grain and martensite block always increased with rising the solid-solution temperature,and austenite grain growth activation energy is 274,969 J/mol.The growth of prior austenite was restricted by primary carbides M6C and MC.The dissolution of the primary carbides not only enhanced solid-solution strengthening and secondary hardening effects but also increased the volume fraction of retained austenite.The increase in the ultimate tensile strength and Charpy U-notch impact energy was primarily attributed to the dissolution of the primary carbides M6C and MC,while the decrease was due to the increase in the size of prior austenite grain and martensite block.Exceptional combination of strength,ductility and toughness with ultimate tensile strength of 2511 MPa,yield strength of 1920 MPa,elongation of 9.5%,reduction of area of 41%and Charpy U-notch impact energy of 19.5 J was obtained when experimental steel was solid-solution treated at 1020℃.
基金Chongqing Light Alloy Materials and Processing Engineering Technology Research Center Open Fund Project(GCZX201903)Yunnan Province Major Science and Technology Special Project Plan(202302AA310038)Sichuan University-Suining Municipal-University Cooperation Project(2023CDSN-12)。
文摘Ti(C,N)-Mo_(2)C-Ni cermet as alternative materials was explored for use in alkaline conditions,replacing the WC-Co cemented carbides,since Co is classified as a potentially carcinogenic substance and there is potential hazard of“hard metal disease”under the exposure to cobalt dust.The changes in microstructure,corrosion rate and volumetric loss rate of the two materials were compared under electrochemical corrosion and erosion-corrosion in alkaline environment.The results demonstrates that Ti(C,N)-Mo_(2)C-Ni cermet undergoes passivation when exposed to electrochemical corrosion of NaOH solution,resulting in a significant increase in oxygen content on the corroded surface.The corrosion rate of cermet is approximately one order of magnitude lower than that of the cemented carbide.Under the erosion-corrosion of an alkaline sand-water mixture,both the cermet and cemented carbide experience a gradual increase in volumetric loss rate with prolonging the erosion time.During erosion,the rim phase in cermet is fragile,so cracks easily penetrate it while the core phase remains intact.The medium-grained cemented carbide commonly demonstrates transgranular fracture mode,while in the fine-grained cemented carbide,cracks tend to propagate along phase boundaries.The erosive wear and damage caused by sand particles play a predominant role in the erosion-corrosion process of alkaline sand-water mixtures.This process represents an accelerated destructive phenomenon influenced and intensified by the combined effects of corrosion and erosion.It is confirmed that using cermet as an alternative anti-wear material to cemented carbides is feasible under alkaline conditions,and even better.
基金supported by Independent Research Project of State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(SKLASS-2023-Z13)the Science and Technology Commission of Shanghai Municipality(No.19DZ2270200)+1 种基金A portion of the work was performed at US National High Magnetic Field Laboratory,which is supported by the National Science Foundation(Cooperative Agreement No.DMR-1157490 and DMR-1644779)the State of Florida.Thanks also to Mary Tyler for editing.
文摘The high-temperature dissolution behavior of primary carbides in samples taken from GCr15 continuous-casting bloom was observed in-situ by confocal laser scanning microscopy.Equations were fitted to the dissolution kinetics of primary carbides during either heating or soaking.Dissolution of carbides proceeded in three stages(fast→slow→faster)as either temperature or holding time was increased.During the heating process and during the first and third stages of the soaking process,the original size of the carbides determined the steepness of the slope,but during the middle(“slow”)stage of the soaking process,the slope remained zero.The initial size of the carbides varied greatly,but their final dissolution temperature fell within the narrow range of 1210-1235℃,and the holding time remained within 50 min.Fractal analysis was used to study the morphological characteristics of small and medium-sized carbides during the dissolution process.According to changes in the fractal dimension before and after soaking,the carbides tended to evolve towards a more regular morphology.
基金supported by the Heilongjiang Province Key Research and Development Program(No.2023ZX07D04)the Fundamental Research Funds for Central Universities and the State Key Laboratory of Marine Coating.
文摘Surface icing and fouling pose a substantial threat to marine facilities.Herein,anti-icing coating composites(F/S-WC-n%/F)with high photo-thermal conversion efficiencies were prepared by spraying a small amount of super-hydrophobic tungsten carbide on fluoro-olefin vinyl ether copolymer(FEVE)at a specific pressure.The photo-thermal properties of the coatings provide them with ice melting and sterilization effects.The delayed icing time of F/S-WC-5%/F is 571 s,with the ice-covered-surface temperature increasing to 42°C after exposure to simulated sunlight.Heat transfer modelling calculations show that icing needs to overcome high Gibbs free energy on F/S-WC-5%/F.Quantum chemistry fundamentally reveals a weak thermodynamic effect of water nucleation on F/S-WC-5%/F,indicating that the icing process requires a high degree of sub-cooling,resulting in delayed icing.In addition,F/S-WC-5%/F can resist different types of fouling and exhibit sterilization activity.Using F/S-WC-5%/F,Escherichia coli germs are killed via heat-induced morphological rupture under a solar simulator.Owing to its excellent environmental versatility,sustainability,mechanical durability and material adaptability,F/S-WC-5%/F is a promising anti-icing and anti-fouling candidate for various practical applications,even in harsh environments.
基金supported by the Natural Science Foundation of Zhejiang Province(Grant No.LQ24F040007)the National Natural Science Foundation of China(Grant No.U22A2075)the Opening Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University)(Grant No.sklpme2024-1-21).
文摘To address the increasing demand for massive data storage and processing,brain-inspired neuromorphic comput-ing systems based on artificial synaptic devices have been actively developed in recent years.Among the various materials inves-tigated for the fabrication of synaptic devices,silicon carbide(SiC)has emerged as a preferred choices due to its high electron mobility,superior thermal conductivity,and excellent thermal stability,which exhibits promising potential for neuromorphic applications in harsh environments.In this review,the recent progress in SiC-based synaptic devices is summarized.Firstly,an in-depth discussion is conducted regarding the categories,working mechanisms,and structural designs of these devices.Subse-quently,several application scenarios for SiC-based synaptic devices are presented.Finally,a few perspectives and directions for their future development are outlined.
基金supported by the Key Project of Chinese Academy of Engineering(No.2019-XZ-11)the General Project of Chinese Academy of Engineering(No.2023-XY-18)+1 种基金the Open Fund of National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials of China(No.HKDNM201907)the Independent Project of State Key Laboratory of Powder Metallurgy,China。
文摘To tackle the common issue of green defects in material extrusion(MEX)additive manufacturing(AM)cemented carbides,warm isostatic pressing(WIP)was introduced to eliminate defects of MEX WC-9Co cemented carbide greens,thereby improving both microstructure uniformity and mechanical properties of sintered bodies.The results indicate that WIP reduces defects in MEX greens,thus decreasing the dimensions and numbers of defects,modifying shapes of pores within sintered bodies,while preserving surface quality and shape characteristics.Compared with WC-9Co prepared via MEX followed by debinding and sintering(DS),the hardness of WC-9Co prepared using MEX-WIP-DS does not change significantly,ranging HV_(30)1494-1508,the transverse rupture strength increases by up to 49.3%,reaching 2998-3514 MPa,and the fracture toughness remains high,ranging 14.8-17.0 MPa·m^(1/2).The mechanical properties surpass comparable cemented carbides fabricated through other AM methods and are comparable to those produced by powder metallurgy.The integration of green WIP into MEX-DS broadens the MEX processing window,and improves the overall mechanical properties of MEX AM WC-Co cemented carbides.
基金National Natural Science Foundation of China(51572224)Guangdong Young Creative Talents(2023KQNCX039)+2 种基金Guangdong Basic and Applied Basic Research Foundation(2023A1515110551)Innovative Team in Higher Educational Institutions of Guangdong Province(2020KCXTD039)2023 Lingnan Normal College Students Innovation and Entrepreneurship Training Program(1742)。
文摘The influence of graphene platelets(GPLs)on the WC grain size of WC-Co-GPLs cemented carbide prepared by low-pressure sintering was investigated.The role of GPLs in refining WC grains was explored by characterizing grain size and phase distribution.Results show that the addition of GPLs leads to significant grain refinement of WC and the more uniform distribution of WC grain size.When the content of GPLs is 0.10wt%,the average WC grain size in the cemented carbide is 0.39μm,which is 32%lower than that in WC-Co.However,the shape of WC grains is almost unaffected,while the mean free path of Co decreases.The grain refinement of WC is attributed to the homogeneous distribution of GPLs between WC/WC and WC/Co grain boundaries,which hinders the solution and precipitation process of WC in liquid phase Co,as well as the migration and growth of WC grains.Additionally,GPLs can serve as heat transfer plates in materials to improve cooling efficiency,thus inhibiting the growth of WC grain.
文摘Tungsten carbide-based(WC-based)cemented carbides are widely recognized as high-performance tool materials.Traditionally,single metals such as cobalt(Co)or nickel(Ni)serve as the binder phase,providing toughness and structural integrity.Replacing this phase with high-entropy alloys(HEAs)offers a promising approach to enhancing mechanical properties and addressing sustainability challenges.However,the complex multi-element composition of HEAs complicates conventional experimental design,making it difficult to explore the vast compositional space efficiently.Traditional trial-and-error methods are time-consuming,resource-intensive,and often ineffective in identifying optimal compositions.In contrast,artificial intelligence(AI)-driven approaches enable rapid screening and optimization of alloy compositions,significantly improving predictive accuracy and interpretability.Feature selection techniques were employed to identify key alloying elements influencing hardness,toughness,and wear resistance.To enhance model interpretability,explainable artificial intelligence(XAI)techniques—SHapley Additive exPlanations(SHAP)and Local Interpretable Model-agnostic Explanations(LIME)—were applied to quantify the contributions of individual elements and uncover complex elemental interactions.Furthermore,a high-throughput machine learning(ML)–driven screening approach was implemented to optimize the binder phase composition,facilitating the discovery of HEAs with superiormechanical properties.Experimental validation demonstrated strong agreement between model predictions and measured performance,confirming the reliability of the ML framework.This study underscores the potential of integrating ML and XAI for data-driven materials design,providing a novel strategy for optimizing high-entropy cemented carbides.
基金The National Natural Science Foundation of China(Grant Nos.523B2063 and 52376089)。
文摘Boron-based fuels,recognized for their high energy density and potential in energetic applications,encounter challenges such as long ignition delays and incomplete combustion,which result in reduced combustion efficiency and limited performance in aerospace propulsion.In this study,boron carbide(B4C)is investigated as an alternative fuel to pristine boron due to its favorable gas-phase combustion.Both metal oxide(nickel oxide(NiO))and metal fluoride(nickel fluoride(NiF_(2)))are selected as oxidizing modifiers to enhance the reactivity of B4C.A method combining laser ignition with optical diagnostics is employed to investigate the enhancing effects of different oxidizers on the ignition and combustion characteristics of B4C.Both NiO and NiF_(2)can significantly increase the combustion radiation intensity and reduce the time to maximum intensity of B4C.Differential scanning calorimetry,in-situ X-ray diffraction,and Fourier transform infrared spectroscopy were used for simultaneous thermal analysis of the B4C composite powders.Combined thermal analysis showed that the effects of NiO and NiF_(2)on promoting B4C combustion is mainly achieved via the formation of NimBn and the release of a large number of gas products.It is reasonable to speculate that the phase separation at the B2O3/NimBn interface forms new pathways for oxygen diffusion and reaction with the B core.The difference in the combustion mechanism of B4C with NiO and NiF_(2)lies in the gas phase products,i.e.,CO_(2)and BF3,respectively,thus leading to significant differences in their reaction processes.
基金the support received from the National Natural Science Foundation of China(No.51908485)the Central Guidance on Local Science and Technology Development Fund of Hebei Province(Nos.246Z3603G and 226Z3603G)。
文摘Common activations of sulfite(S(Ⅳ))-based advanced oxidation processes(AOPs)utilized metal ions and oxides as catalysts,which are constrained by challenges in catalyst recovery,inadequate stability,and susceptibility to secondary pollution in application.Calcium sulfite(CaSO_(3)),one of the byproducts of flue gas desulfurization,is of interest in AOPs because of its ability to slowly release S(Ⅳ),low toxicity,and costeffectiveness.Therefore,a heterogenous activator,molybdenum carbide(Mo_(2)C)was selected to stimulate Ca SO3for typical antibiotic elimination.Benefiting from the dissociation form of HSO_(3^(-))from CaSO_(3)and improved electron transfer of Mo_(2)C at pH 6,the simulated target metronidazole(MTZ)can be removed by 85.65%with rate constant of 0.02424 min^(-1)under near-neutral circumstance.The combining determinations of quenching test,electron spin resonance spectrum,and reactive species probe demonstrated singlet oxygen(^(1)O_(2))and sulfate radicals played leading role for MTZ decontamination.Characterization and theoretical calculation suggested the alteration of Mo valence state drove the activation of S(Ⅳ),and revealed that dissolved oxygen promoted the adsorption of HSO_(3^(-))on the surface of Mo_(2)C,then facilitating production of^(1)O_(2).The favorable stability and applicability for Mo_(2)C/CaSO_(3)process indicated an applied prospect in actual pharmaceutical wastewater.
基金supported by the Natural Science Foundation of China(82202751,Derong Xu,82372478,Chuanli Zhou,62375249,U1803128,Meng Qiu)the Taishan Scholar Project(tsqn202211362,Chuanli Zhou,tsqn201909054,Meng Qiu)+1 种基金the Natural Science Foundation of Shandong Province(ZR2021MH020,Chuanli Zhou,ZR2022JQ22,Meng Qiu)the Fundamental Research Funds for the Central Universities(202341006,Meng Qiu)。
文摘Photo-Cross-Linkable hydrogel has attracted immense interest in the regeneration of bone repair and regeneration strategies due to its superior biocompatibility and tunable mechanical properties.Recently,Nb was reported to strongly promote the bone regeneration process via an accelerated osteoblast-modulated alkaline phosphatase activity mechanism.In particular,Nb2C MXenes have drawn widespread attention due to their excellent biocompatibility and ability to induce bone formation.However,the easy agglomeration of Nb2C nanosheets and subsequent low cell endocytosis efficacy greatly suppressed the osteogenesis effect.In this study,a subtractive nanopore-engineered Nb2C MXene was prepared through a microwave combustion method,gelatin methacrylate was used as the carrier hydrogel,and the photo-triggered Porous-Nb2C@GelMA hydrogel was fabricated by a photo-triggered process.The pore-forming strategy not only successfully improved the distribution of Nb2C and formed more homogenous Porous-Nb2C@GelMA hydrogels but also guided bone marrow mesenchymal stem cells(BMSCs)toward osteoblast differentiation.Porous Nb2C provided convenient cellular grasping and endocytosis for BMSCs,which further created a favorable environment for differentiation and osteogenesis.This,in turn,leads to an increase in the expression of osteogenic markers,such as ALP and ARS,as well as osteogenic factors,such as BMP-2,COL-1,OCN,and OPN.Consequently,enhancing the regenerative microenvironment by incorporating porous Nb2C composite hydrogels shows promise for application in bone regeneration.
基金supported by the National Key R&D Program of China(2020YFA0714900,2023YFB3709903)the National Natural Science Foundation of China(U21B2082,52474410)+6 种基金the Key R&D Program of Shandong Province,China(2023CXGC010406)the Scientific Research Special Project for First-Class Disciplines in Inner Mongolia Autonomous Region(YLXKZX-NKD-001)the International Science and Technology Cooperation Project of Higher Education Institutions in Inner Mongolia Autonomous Region(GHXM-002)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(2024ZD06)the Technology Support Project for the Construction of Major Innovation Platforms in Inner Mongolia Autonomous Region(XM2024XTGXQ16)the Beijing Municipal Natural Science Foundation(2222065)the Fundamental Research Funds for the Central Universities(FRF-TP-22-02C2).
文摘Traditional heat treatment methods require a significant amount of time and energy to affect atomic diffusion and enhance the spheroidization process of carbides in bearing steel,while pulsed current can accelerate atomic diffusion to achieve ultra-fast spheroidization of carbides.However,the understanding of the mechanism by which different pulse current parameters regulate the dissolution behavior of carbides requires a large amount of experimental data to support,which limits the application of pulse current technology in the field of heat treatment.Based on this,quantify the obtained pulse current processing data to create an important dataset that could be applied to machine learning.Through machine learning,the mechanism of mutual influence between carbide regulation and various factors was elucidated,and the optimal spheroidization process parameters were determined.Compared to the 20 h required for traditional heat treatment,the application of pulsed electric current technology achieved ultra-fast spheroidization of GCr15 bearing steel within 90 min.
基金financial support of the Central Guide Local Science and Technology Development Project of Hubei Province of China(No.2023EGA008)the Wuhan Natural Science Foundation Exploration Project(Chenguang Project)(No.2024040801020309).
文摘As the main use of TBM(tunnel boring machine)cutter ring(DC53 steel)currently is difficult to meet the requirements of high wear resistance and high toughness synchronously in its service environment,a new HWR0 steel with 4%Cr-3%V for TBM cutter ring has been developed to control carbides in steel.Precipitation behavior of carbides in HWR0 steel was investigated through theoretical calculation by Thermo-Calc and experimental measurement using scanning electron microscope,energy dispersive spectrometer,electron probe X-ray micro-analyzer,and laser particle size analyzer.The results show that three different carbides are precipitated during cooling.And the as-cast electroslag remelting ingot of HWR0 steel primarily consists of many blocky or strip-like MC distributed along grain boundaries,few chrysanthemum-like M_(6)C concentrated at grain boundary intersections,and a large quantity of fine M_(23)C_(6)and M_(6)C dispersed in the matrix.Compared with DC53 steel,HWR0 steel has more high-hardness carbides MC,which are discontinuously distributed at the grain boundaries,achieving the dual improvement of wear resistance and impact toughness.Cooling rates significantly influence the carbides distribution and grain size.A slower cooling rate exacerbates the segregation of alloying elements,which leads to the localized enrichment of Mo and the subsequent precipitation of M_(6)C carbides at grain boundary intersections.In contrast,faster cooling rate decreases the element segregation,promotes carbide nucleation and limits the space for carbides growth,which results in finer size and distribution of carbides and grains.Higher cooling rates yield a more homogeneous microstructure with uniform MC compositions and promote the preferential formation of M_(6)C carbides along grain boundaries,which enhances the mechanical properties.
基金Funded by the Guangxi Key Research and Development Program(Guike AB23026071 and Guike AB24010020)the Guangxi Science and Technology Base and Talent Project(Guike AD24010062)the Guangxi Beibu Gulf Engineering Research Center for Green Marine Materials。
文摘This study introduced a low-temperature thermochemical method for the treatment of EMR in the presence of carbide slag(CS)to achieve an economical and efficient harmless effect.The experimental results indicate that,under suitable conditions,the NH_(4)^(+)and Mn^(2+)contents in EMR decrease notably with the increasing CS content,accompanied by an increase in pH value.Furthermore,the concentration of NH_(4)^(+)in EMR considerably decreases with the increasing liquid-to-solid ratio,eventually stabilizing.Similarly,the pH value first increases and then decreases,ultimately stabilizing.At a CS content of 12%and a liquid-to-solid ratio of 0.7,the leaching concentrations of NH_(4)^(+)and Mn^(2+)in EMR(127.7 mg/kg and 0.15 mg/L,respectively)fall below the standard detection limit(2 mg/L),with the pH measuring 8.26,meeting the conditions outlined in the GB 8978.NH_(4)^(+)is converted to NH_(3),while Mn^(2+)is transformed into solid precipitates such as Mn(OH)_(2),Mn_(2)O_(3),MnO_(2),Ca_(3)Mn_(2)O_(7),and Ca_(2)MnO_(4).The majority of manganese ions exist in trivalent or tetravalent states and remain stable over time.The cost of using CS as a reagent for treating 1 ton of EMR is merely$1.01.The high OH^(-)concentration provided by CS enables the effective removal of NH_(4)^(+)from EMR and the solidification of Mn^(2+)during thermal reactions.
文摘The direct deoxygenative homo-coupling of benzyl alcohols holds great promise to build up bibenzyl motifs in organic synthesis,yet it remains a grand challenge in selectivity and activity control.Herein,we first discovered that iron carbide catalysts displayed high efficiency and selectivity in the catalytic deoxygenative homo-coupling of benzyl alcohols into bibenzyls using H_(2)as the reductant.Ir-promoted Fe0@Fe_(5)C_(2)gave the best performance among the investigated catalysts,and a broad scope of substrates with diverse functional groups could be smoothly converted into bibenzyls,with the yield up to 85%.In addition,in the presence of alkenes,three-component coupling reactions between alcohols and alkenes were also for the first time achieved to construct more complex multi-ring molecules.The radical-trapping experiment and FTIR measurements revealed the radical nature of the reaction and the significantly promoted C–O bond activation after carbonization,respectively.This work will provide guidelines for the rational design of efficient and selective catalysts for the alcohol-involved carbon-carbon coupling reactions.
基金supported by the National Natural Science Foundation of China(Grant Nos.52375420,52322510)Natural Science Foundation of Heilongjiang Province of China(Grant No.YQ2023E014)+6 种基金National Key Research and Development Program of China(Grant No.2021YFB3400403)Shenzhen Science and Technology Program(Grant No.GNCWSSJH20240032)Self-Planned Task(Grant No.SKLRS202214B)of State Key Laboratory of Robotics and System(HIT),China Postdoctoral Science Foundation(Grant No.2022T150163)Young Elite Scientists Sponsorship Program by CAST(Grant No.YESS20220463)Open Fund of Key Laboratory of Microsystems and Microstructures Manufacturing(HIT)(Grant No.2022KM004)Open Foundation of Hunan Provincial Key Laboratory of High Efficiency and Precision Machining of Difficult-to-Cut Material(Grant No.E22445)Fundamental Research Funds for the Central Universities(Grant Nos.HIT.OCEF.2022024,FRFCU5710051122)。
文摘Silicon carbide(SiC)ceramics are extensively utilized in aerospace,national defense,and petrochemical industries due to their superior physical and chemical properties.The processing of bulk SiC ceramics necessitates precise and efficient grinding techniques to produce components with satisfactory functionality.However,the inherent high hardness and brittleness of SiC ceramics present significant challenges during grinding,leading to severe brittle fracture and tool wear that compromise both surface integrity and production efficiency.Although ductile-regime grinding of SiC ceramics can be achieved by enhancing machine tool accuracy and stiffness while optimizing wheel performance alongside appropriate selection of process parameters,a comprehensive summary of the mechanisms underlying damage evolution during grinding is lacking,and a mature grinding process for SiC ceramics has yet to be developed.To bridge this gap,the sintering technologies,mechanical properties,and microstructures of SiC ceramics were briefly covered.The grinding-induced damage mechanism and low-damage grinding technologies of SiC ceramics were summarized.The fundamental science underlying the ductile deformation and removal mechanisms of brittle solids was emphasized.Additionally,attention was directed towards the critical role of hybrid energy field grinding in minimizing brittle damages and promoting removal efficiency.This review not only elucidates the intrinsic interactions between the work material and abrasives,but also offers valuable insights for optimizing the grinding processes of brittle solids.
基金the National Natural Science Foundation of China(52175517,51720105016,and 52405599)the China National Postdoctoral Program for Innovative Talents(BX20230289)+2 种基金the China Postdoctoral Science Foundation(2024M752567)the Recruitment Program of Global Experts(WQ2017610445)the Innovation Capability Support Program of Shaanxi Province(2021TD-23).
文摘Microelectromechanical system(MEMS)high-temperature pressure sensors are widely used in aerospace,petrochemical industries,automotive electronics,and other fields owing to their advantages of miniaturization,lightweight design,simplified signal processing,and high accuracy.In recent years,advances in semiconductor material growth technology and intelligent equipment operation have significantly increased interest in high-temperature pressure sensors based on the third-generation semiconductor silicon carbide(SiC).This review examines the material properties of SiC single crystals and discusses several technologies influencing the performance of SiC pressure sensors,including the piezoresistive effect,ohmic contact,etching processes,and packaging methodologies.Additionally,it explores future research directions in the field.The review highlights the importance of increasing operating temperatures and advancing sensor integration as critical trends for future SiC high-temperature pressure sensor research and applications.
基金funded by the National Natural Science Foundation of China(Grant Nos.52201171 and 52225103)the Fundamental Research Funds for the Central Universities,China(Grant No.FRF-IDRY-23-001)the National Key Research and Development Program of China(Grant No.2022YFB4602101).
文摘Tantalum(Ta)alloys have been widely utilized in rocket,air-breathing engines,and airframe applications.However,traditional Ta alloys suffer from insufficient strength at ultra-high temperature,making it challenging to satisfy the design requirements for next-generation aerospace equipment.We report a novel strategy to design Ta alloys with superior mechanical properties by integrating the multi-principal element concept with compositionally complex carbides.By introducing multiple refractory elements and C,the resultant alloys displayed a thermally stable microstructure consisting of two phases.With the increasing C contents,the microstructure evolved from hypoeutectic to eutectic and then to hypereutectic.These varying microstructural characteristics influenced crack blunting and dislocation accumulation behaviors,leading to different softening resistance at 1600℃and plasticity at room temperature.Benefiting from the strengthening effects of solid solution and compositionally complex carbides,these alloys exhibited a high strength of~600 MPa at 1600℃,significantly superior than that of traditional Ta alloys.
