Three types of NdFeB magnets with the same composition and different grain sizes were prepared,and then the grain boundary diffusion was conducted using metal Tb under the same technical parameters.The effect of grain...Three types of NdFeB magnets with the same composition and different grain sizes were prepared,and then the grain boundary diffusion was conducted using metal Tb under the same technical parameters.The effect of grain size on the grain boundary diffusion process and properties of sintered NdFeB magnets was investigated.The diffusion process was assessed using X-ray diffractometer,field emission scanning electron microscope,and electron probe microanalyzer.The magnetic properties of the magnet before and after diffusion were investigated.The results show that the grain refinement of the magnet leads to higher Tb utilization efficiency and results in higher coercivity at different temperatures.It can be attributed to the formation of a deeper and more complete core-shell structure,resulting in better magnetic isolation and higher anisotropy of the Nd_(2)Fe_(14)B grains.This work may shed light on developing high coercivity with low heavy rare earth elements through grain refinement.展开更多
The low coercivity is the major factor inhibiting the large-scale commercial utilization of Nd-Ce-Fe-B sintered magnets.In this work,we achieved a record-high coercivity of 15.04 kOe in Ga-doped Nd-Ce-Fe-B sintered ma...The low coercivity is the major factor inhibiting the large-scale commercial utilization of Nd-Ce-Fe-B sintered magnets.In this work,we achieved a record-high coercivity of 15.04 kOe in Ga-doped Nd-Ce-Fe-B sintered magnets with 30 wt%Ce replacing Nd,demonstrating enormous potential.The Ga-doped Nd-Ce-Fe-B magnets with higher boron(HB)and lower boron(LB)content are designed.The coercivity of the HB magnet increases slightly from 10.80 to 12.26 kOe after annealing,attributed to the optimized distribution of grain boundary(GB)phases.In contrast,the coercivity of the LB magnet remarkably increases from 8.13 to 15.04 kOe after annealing.Microstructural observations indicate that the narrow GB phase in the as-sintered magnet is rich in Fe,and the strong exchange coupling of adjacent grains resulted in low coercivity.The evolution of Ga-rich phases reveals a potential formation mechanism of the RE_(6)Fe_(13)Ga phase,that is the RE-Fe amorphous phase and REGa phase in the as-sintered magnet combine to form the RE_(6)Fe_(13)Ga phase and RE-Ga amorphous phase during post-sinter annealing(RE:rare earth).Moreover,the GB phase of the annealed magnet transforms into a Fe-lean phase with a thickness of 16.4 nm.Magnetization and demagnetization behavior characterizations reveal that the exchange decoupling of adjacent grains induced by the optimized GB phases is the main reason for the remarkable coercivity enhancement,which is also validated by micromagnetic simulations.展开更多
In this work,the effect of the Al addition amount in the TbAl coatings on the grain boundary diffusion proces s(GBDP)of Tb were systematically explored.Direct current magnetron sputtering(DCMS)method was utilized in c...In this work,the effect of the Al addition amount in the TbAl coatings on the grain boundary diffusion proces s(GBDP)of Tb were systematically explored.Direct current magnetron sputtering(DCMS)method was utilized in co-sputtering manner to synthesize the TbAl coatings with certain Tb consumption and various Al addition amount.Results show that the moderate Al addition amount significantly improves the wettability of grain boundary(GB)phases,thereby acquiring more continuous and uniform Tb-rich shells and GB phases between matrix phases,as well as deeper diffusion depth and denser microstructure.The largest increase amplitude of intrinsic coercivity(Hcj)is improved by 78.4%in TbAIdiffused magnet compared to the pure Tb-diffused magnet,while the remanence(Br)is expected to show an overall decreasing tendency accompanied with a slight increase in the decreasing process.However,when the Al addition amount is excessive,magnetic dilution effect is enhanced,and the Tbrich shells and GB phases between matrix phases become fuzzy and even invisible,which in turn deteriorates the magnetic properties of diffused magnets.展开更多
Commercial N52 sintered NdFeB magnets were processed by grain boundary diffusion(GBD)with Dy-Co-M(M=Cu,AI)alloys.The coercivity of magnets greatly increase to 17.62 and 18.83 kOe respectively when diffusing Dy_(58)Co_...Commercial N52 sintered NdFeB magnets were processed by grain boundary diffusion(GBD)with Dy-Co-M(M=Cu,AI)alloys.The coercivity of magnets greatly increase to 17.62 and 18.83 kOe respectively when diffusing Dy_(58)Co_(25)Cu_(17)and Dy_(58)Co_(25)Al_(17)alloys,which are obviously higher than that of Dy58Co42GBD-treated magnet with 16.64 kOe,Further thermal stability studies indicate that the thermal stability of Dy_(58)Co_(25)Cu_(17)and Dy_(58)Co_(25)Al_(17)GBD-treated magnets is further improved compared to the Dy58Co42GBD-treated magnet The results show that th e temperature coefficients of remanence(20-120℃)are reduced from-0.148%/℃to-0.134%/℃and-0.132%/℃by Dy_(58)Co_(25)Cu_(17)and Dy_(58)Co_(25)Al_(17)GBD-treatment,respectively.Besides,the irreversible magnetic flux losses(120℃)for Dy_(58)Co_(25)Cu_(17)and Dy_(58)Co_(25)Al_(17)diffusion magnets are 4.76%and 2.79%,respectively.Microstructural analyses demonstrate that the presence of Cu and Al elements reduces the excessive accumulation of Dy and Co on the surface in the diffusion magnets an d improves the diffusion depth and utilization of Dy and Co.Furthermore,the flow of Co from the triple junction phase to the thin grain boundary phase is promoted,which contributes to the uniform distribution of Co.In addition,the dynamic evolution of the magnetic domain structure during the temperature rise process was studied.This work provides insight into the preparation of high-performance and high-thermal stability magnets.展开更多
In this work,we present an innovative method for fabricating high-performance proton-conductive fuel cells(PCFCs)by combining magnetron sputtering and flashlight sintering(FLS)techniques.BaZr_(0.8)Y_(0.2)O_(3–δ)(BZY...In this work,we present an innovative method for fabricating high-performance proton-conductive fuel cells(PCFCs)by combining magnetron sputtering and flashlight sintering(FLS)techniques.BaZr_(0.8)Y_(0.2)O_(3–δ)(BZY20)electrolyte thin-films are successfully prepared by improving the crystallinity while maintaining the stoichiometry.All components of PCFC,Ni-YSZ anode,BZY20 electrolyte and Pt-GDC cathode are fabricated by sequentially sputtering them onto an AAO substrate.Electrolytic sintering is performed at 550 and 650 V conditions using FLS,effectively solving the Ba evaporation problem encountered in conventional thermal sintering methods.XRD analysis confirms that the perovskite structure is retained,and crystallinity is improved in the FLS samples.Furthermore,FE-SEM and EDS analyses confirm the uniform elemental distribution and consistent thickness of the FLS-treated electrolyte.An optimized PCFC unit cell with FLS-treated electrolyte exhibits a peak power density of 200.0 mW cm^(-2) at 500℃ and an ohmic resistance of 376.0 mΩ cm^(-2).These results suggest that the combination of magnetron sputtering and FLS techniques is a promising approach for fabricating highperformance thin-film PCFCs.展开更多
This study demonstrates the successful fabrication of solid-state bilayers using LiFePO_(4)(LFP)cathodes and Li_(1.3)Al_(0.3)Ti_(1.7)(PO_(4))_(3)(LATP)-based Composite Solid Electrolytes(CSEs)via Cold Sintering Proces...This study demonstrates the successful fabrication of solid-state bilayers using LiFePO_(4)(LFP)cathodes and Li_(1.3)Al_(0.3)Ti_(1.7)(PO_(4))_(3)(LATP)-based Composite Solid Electrolytes(CSEs)via Cold Sintering Process(CSP).By optimizing the sintering pressure,it is achieved an intimate contact between the cathode and the solid electrolyte,leading to an enhanced electrochemical performance.Bilayers cold sintered at 300 MPa and a low-sintering temperature of 150℃exhibit high ionic conductivities(0.5 mS cm^(-1))and stable specific capacities at room temperature(160.1 mAh g^(-1)LFP at C/10 and 75.8 mAh g^(-1)_(LFP)at 1 C).Moreover,an operando electrochemical impedance spectroscopy(EIS)technique is employed to identify limiting factors of the bilayer kinetics and to anticipate the overall electrochemical behavior.Results suggest that capacity fading can occur in samples prepared with high sintering pressures due to a volume reduction in the LFP crystalline cell.This work demonstrates the potential of CSP to produce straightforward high-performance bilayers and introduces a valuable non-destructive instrument for understanding and avoiding degradation in solid-state lithium-based batteries.展开更多
Silver paste is widely used in power electronics as a die-attach material owing to its low-temperature sinterability,high melting point,and excellent electrical and thermal conductivities in sintered joints.However,ow...Silver paste is widely used in power electronics as a die-attach material owing to its low-temperature sinterability,high melting point,and excellent electrical and thermal conductivities in sintered joints.However,owing to the mismatch in the coefficient of thermal expansion(CTE)between the joints and chip,the high Young's modulus of sintered silver hinders the mitigation of the high thermal stress generated during the operation of power modules,which increases the susceptibility of sintered joints to cracking,thereby leading to potential failure.This study developed a facile approach to synthesizing bayberry-like Ag microparticles(AgMPs)through the in situ assembly of silver nanorods,resulting in a uniform distribution of nanoscale structures and mesopores on the particle surface.These particles exhibited a high specific surface area of 2.5389 m^(2)·g^(-1),which enhanced theirsintering activity,enabling sintering to occur at 149.7℃.Furthermore,the porous structure of the AgMPs effectively reduced the density of joints formed by sintering AgMP paste,thereby lowering the Young's modulus of the joints.The small grain size and intricate internal substructure of the joints yielded high shear strength,which reached112.50 MPa at 250℃.The Young's modulus could be adjusted,and the pores provided by the AgMPs maintained the Young's modulus within a low range(15.11-29.61GPa),effectively mitigating thermal stress.These new bayberry-like porous AgMPs offer a promising option for die-attach materials in electronic packaging.展开更多
Low cobalt(Co)WC hard materials were prepared using vacuum sintering.The influences of Co content on the sintering densification behavior,grain growth characteristics,microstructure and mechanical properties of WC har...Low cobalt(Co)WC hard materials were prepared using vacuum sintering.The influences of Co content on the sintering densification behavior,grain growth characteristics,microstructure and mechanical properties of WC hard material were studied.The experimental results show that the addition of a small amount of Co significantly promotes the densification and reduces the sintering temperature.Meantime,the abnormal growth of WC grains was observed.When the sintering temperature is 1300℃and the content of Co is less than 1.0wt%,densed WC/Co hard material with fine grains is obtained.When the content of Co is 1wt%,the relative density,Vickers hardness,and flexural strength of WC material are 98.76±0.17%,24.23±0.41 GPa,and 1376±67 MPa,respectively.When the Co content is 0.25wt%and 0.5wt%,the optimal sintering temperature of the sample is 1350℃.Among them,the relative density,hardness,and flexural strength of WC-0.5wt%Co are 98.79±0.15%,23.44±0.38 GPa,and 1233±85 MPa,respectively.展开更多
Grain boundary diffusion process(GBDP)is a widely used method of increasing the coercivity of sintered NdFeB magnets.In this study,the effects of the GBDP on the bending strength and microhardness of sintered NdFeB ma...Grain boundary diffusion process(GBDP)is a widely used method of increasing the coercivity of sintered NdFeB magnets.In this study,the effects of the GBDP on the bending strength and microhardness of sintered NdFeB magnets and the fracture mode were investigated.Results show that the bending strength of magnets is reduced by pickling and heat treatment and greatly recove rs after heavy rare earth element(Tb)grain boundary diffusion.The pickling and the heat treatment cause a slight decrease in microhardness.Compared with the recovery of the bending strength,the hardness decreases after the GBDP.The fracture mode of bended magnets changes from intergranular to transgranular.This study helps in further improving the mechanical and magnetic properties of sintered NdFeB magnets.展开更多
Sintered silver nanoparticles(AgNPs)arewidely used in high-power electronics due to their exceptional properties.However,the material reliability is significantly affected by various microscopic defects.In this work,t...Sintered silver nanoparticles(AgNPs)arewidely used in high-power electronics due to their exceptional properties.However,the material reliability is significantly affected by various microscopic defects.In this work,the three primary micro-defect types at potential stress concentrations in sintered AgNPs are identified,categorized,and quantified.Molecular dynamics(MD)simulations are employed to observe the failure evolution of different microscopic defects.The dominant mechanisms responsible for this evolution are dislocation nucleation and dislocation motion.At the same time,this paper clarifies the quantitative relationship between the tensile strain amount and the failure mechanism transitions of the three defect types by defining key strain points.The impact of defect types on the failure process is also discussed.Furthermore,traction-separation curves extracted from microscopic defect evolutions serve as a bridge to connect the macro-scale model.The validity of the crack propagation model is confirmed through tensile tests.Finally,we thoroughly analyze how micro-defect types influence macro-crack propagation and attempt to find supporting evidence from the MD model.Our findings provide a multi-perspective reference for the reliability analysis of sintered AgNPs.展开更多
In traditional Nd-Fe-B-based sintered magnets,the composition,role of each element and microstruc-tures have been extensively investigated globally since they were invented in 1983.However,the effects of boron(B)conte...In traditional Nd-Fe-B-based sintered magnets,the composition,role of each element and microstruc-tures have been extensively investigated globally since they were invented in 1983.However,the effects of boron(B)content and post-sinter annealing(PSA)on the microstructure and magnetic properties have been least studied so far and the relative mechanisms are not yet clear.In this paper,we investigated the influence of B on the magnetic performance and microstructure of Nd-Fe-B sintered magnets origi-nally containing copper(Cu),gallium(Ga)and titanium(Ti).It is shown that the intrinsic coercivity has a substantial increment of 2.86 kOe and the remanence has a slight reduction of 0.16 kGs when B content is reduced from 0.980 wt.%to 0.900 wt.%.Moreover,there is a coercivity increment of 27.3%and 65.3%for samples with 0.980 wt.%and 0.900 wt.%B content after PSA,respectively.It is shown that the im-pacts of B content and PSA are significant and their regulation mechanisms are worthwhile to be studied systematically.Furthermore,it is revealed by microstructural analysis that high coercivity of the sample with 0.900 wt.%B after PSA results from the uniform distribution of Ga,Cu,Nd,and the formation of RE 6(Fe,M)14(RE=Pr,Nd,M=Cu,Ga)compound in triple junction phases.The dilution of Fe content in grain boundary phases(GB phases)also plays an important role.It is found out that decrease of the re-manence is mainly due to reduction of the matrix phase and c-axis alignment degree.In this study,we explored a new path to develop Nd-Fe-B-based sintered magnets with high comprehensive properties by novel approaches through varying B content,PSA technique and co-adding trace elements.展开更多
Establishing a base on the Moon is one of the new goals of human lunar exploration in recent years.Sintered lunar regolith is one of the most potential building materials for lunar bases.The physical,mechanical and th...Establishing a base on the Moon is one of the new goals of human lunar exploration in recent years.Sintered lunar regolith is one of the most potential building materials for lunar bases.The physical,mechanical and thermal properties of sintered lunar regolith are vital performance indices for the structural design of a lunar base and analysis of many critical mechanical and thermal issues.In this study,the HUST-1 lunar regolith simulant(HLRS)was sintered at 1030,1040,1050,1060,1070,and 1080℃.The effect of sintering temperature on the compressive strength was investigated,and the exact value of the optimum vacuum sintering temperature was determined between 1040 and 1060℃.Then,the microstructure and material composition of vacuum sintered HLRS at different temperatures were characterized.It was found that the sintering temperature has no significant effect on the mineral composition in the temperature range of 1030-1080℃.Besides,the heat capacity,thermal conductivity,and coefficient of thermal expansion(CTE)of vacuum sintered HLRS at different temperatures were investigated.Specific heat capacity of sintered samples increases with the increase of test temperature within the temperature range from-75 to 145℃.Besides,the thermal conductivity of the sintered sample is proportional to density.Finally,the two temperatures of 1040 and 1050℃were selected for a more detailed study of mechanical properties.The results showed that compressive strength of sintered sample is much higher than tensile strength.This study reveals the effects of sintering temperature on the physical,mechanical and thermal properties of vacuum sintered HLRS,and these material parameters will provide support for the construction of future lunar bases.展开更多
This study investigates full liquid phase sintering as a process of fabrication parts from WE43(Mg-4wt.%Y-3wt.%RE-0.7wt.%Zr)alloy using binder jetting additive manufacturing(BJAM).This fabrication process is being dev...This study investigates full liquid phase sintering as a process of fabrication parts from WE43(Mg-4wt.%Y-3wt.%RE-0.7wt.%Zr)alloy using binder jetting additive manufacturing(BJAM).This fabrication process is being developed for use in producing structural or biomedical devices.Specifically,this study focused on achieving a near-dense microstructure with WE43 Mg alloy while substantially reducing the duration of sintering post-processing after BJAM part rendering.The optimal process resulted in microstructure with 2.5%porosity and significantly reduced sintering time.The improved sintering can be explained by the presence of Y_(2)O_(3)and Nd_(2)O_(3)oxide layers,which form spontaneously on the surface of WE43 powder used in BJAM.These layers appear to be crucial in preventing shape distortion of the resulting samples and in enabling the development of sintering necks,particularly under sintering conditions exceeding the liquidus temperature of WE43 alloy.Sintered WE43 specimens rendered by BJAM achieved significant improvement in both corrosion resistance and mechanical properties through reduced porosity levels related to the sintering time.展开更多
Core-shell MoSi_(2)@Nb powder was prepared by electrostatic layer self-assembly method.The surfactants SDS(CHSO_(4)Na)and CTAB(C_(19)H_(42)BrN)were used to modify the surface of the two particles to make them charged,...Core-shell MoSi_(2)@Nb powder was prepared by electrostatic layer self-assembly method.The surfactants SDS(CHSO_(4)Na)and CTAB(C_(19)H_(42)BrN)were used to modify the surface of the two particles to make them charged,and the Zeta potential of the suspension was tested by the Zeta potentiometer.Scanning electron microscope,transmission electron microscope and energy dispersive spectrometer were used to characterize the phase,morphology,microstructure and element distribution of synthetic materials.The results show that when the SDS concentration is 2 mmol/L,the CTAB concentration is 3mmol/L and the pH value of Nb suspension is 5,the coating effect is better after secondary cladding.NbSi_(2)phase is found at the interface between Nb and MoSi_(2)after calcination at 200℃ for 2 h in Ar atmosphere,indicating that Nb is highly active and reacts with Si.Core-shell structure is still retained in MoSi_(2)@Nb material after spark plasma sintering at 1450℃ for 2 h under uniaxial pressure of 40 MPa.However,it is found that Nb reacts strongly with MoSi_(2),and most of the Nb phase is reacted.This issue needs to be addressed in subsequent studies.The fracture toughness(K_(IC))of MoSi_(2)@Nb material is significantly improved to 5.75 MPa·m^(0.5)compared with that of MoSi_(2)material(3.32 MPa·m^(0.5)).展开更多
A procedure of low temperature solid-phase sintering（LTSS） was carried out to fabricate sintered metal fibrous media（SMFM） with high specific surface area.Stainless steel fibers which were produced by cutting proc...A procedure of low temperature solid-phase sintering（LTSS） was carried out to fabricate sintered metal fibrous media（SMFM） with high specific surface area.Stainless steel fibers which were produced by cutting process were first plated with a coarse copper coating layer by electroless plating process.A low-temperature sintering process was then completed at about 800 °C for 1 h under the protection of hydrogen atmosphere.The results show that a novel SMFM with complex surface morphology and high specific surface area（0.2 m2/g） can be obtained in this way.The effect of sintering temperature on the surface morphology and specific surface area of SMFM was studied by means of scanning electron microscopy and Brunauer-Emmett-Teller.The damage of micro-structure during the sintering process mainly contributed to the loss of specific surface area of SMFM and the optimal sintering temperature was 800 °C.展开更多
Fabrication, characterization and performance of a porous metal-fiber sintered felt （PMFSF） based on multi-tooth cutting and solid-phase sintering were studied. The PMFSF was used as the anodic methanol barrier in a...Fabrication, characterization and performance of a porous metal-fiber sintered felt （PMFSF） based on multi-tooth cutting and solid-phase sintering were studied. The PMFSF was used as the anodic methanol barrier in a passive air-breathing direct methanol fuel cell to mitigate the effects of methanol crossover. Compared with the commercial SUS316L felt made of bundle-drawn fibers, this self-made PMFSF has larger pore diameter, polarized pore distribution, irregular fiber shape, rougher surface, lower mass flow resistance and evident hydrophobicity. The results reveal that the use of a PMFSF significantly enhances the cell performance since it helps to maintain a balance between the reactant and product management while depressing methanol crossover. The PMFSF with a porosity of 70% yields the highest cell performance at a methanol concentration of 4 mol/L.展开更多
MnS growth in sintered steels with admixed Fe, Cu, C and MnS has been investigated by SEM and X-ray diffraction, MnS in Fe-Cu-C-MnS sintered steels in which MnS has been admixed is not stable and MnS growth may be asc...MnS growth in sintered steels with admixed Fe, Cu, C and MnS has been investigated by SEM and X-ray diffraction, MnS in Fe-Cu-C-MnS sintered steels in which MnS has been admixed is not stable and MnS growth may be ascribed to sintering between MnS particles or reaction between MnS and Fe, Cu, C elements.展开更多
Polyamide(PA)is a widely utilized engineering polymer,and its thermal and mechanical properties can be further improved by adding nanofillers.However,adding inorganic fullerene-like tungsten disulfide(IF-WS_(2))nanopa...Polyamide(PA)is a widely utilized engineering polymer,and its thermal and mechanical properties can be further improved by adding nanofillers.However,adding inorganic fullerene-like tungsten disulfide(IF-WS_(2))nanoparticles(NPs)to PA to produce composite precursor powders for additive manufacturing is challenging.Here,we report a novel and cost-effective method for fabricating PA-12 based nanocomposite(NC)powders with fixed/partially encapsulated IF-WS_(2) nanoparticulate fillers utilizing an advanced mixing technique because simple wet mixing(WM)can only attach fillers weakly to the powder surfaces when compared to the proposed method.The resulting nanocomposite powders maintained nearly the original particle size distribution of PA-12.They also exhibited improved rheological properties,melting,and crystallization behaviors compared with those prepared by the WM method.The laser-sintered PA-12 nanocomposite specimens revealed enhanced pow-der thermal stability and higher tensile strengths than pristine PA-12,validating the advantages of the novel technique for the fabrication of polyamide nanocomposite powders and their suitability for utilization in laser sintering additive manufacturing.These results demonstrate that high-performance engineered PA-12 nanocom-posite components can be directly laser sintered,and this technique can potentially be extended to fabricate other engineered polymeric nanocomposite powders.展开更多
Three different kinds of corundum aggregates-tabular sintered alumina, dense sintered alumina, and fused dense corundum-were introduced into the silica fume .free or silica fume containing Al2O3 -SiC - C iron runner c...Three different kinds of corundum aggregates-tabular sintered alumina, dense sintered alumina, and fused dense corundum-were introduced into the silica fume .free or silica fume containing Al2O3 -SiC - C iron runner castables to investigate their influences on the flow ability, linear change on heating, bulk density, apparent porosity, cold strength, hot modulus of rupture, therm, al shock resistance, slag resistance, oxidation resistance as well as wear resistance of Al2O3 - SiC - C iron runner castables. The results show that （ 1 ） compared with the specimens with fused dense corundum, the specimens with dense sintered alumina have equivalent installation property, slag resistance and oxidation resistance, equivalent or even higher cold modulus of rupture, cold crushing strength and hot modulus of rupture, exhibiting better thermal shock resistance and cold wear resistance ; （2） adopting bimodal alumina micropowder LISAL22RABL as well as water reducers ZX2 and ZD2 can well reduce the water requirement of silica fume free castables, solving the problem of deteriorated flow ability resulted from the lack of silica fume; since the lack of silica fume avoids the formation of low melting point liquid, the hot modulus of rupture and the thermal shock resistance of the silica fume free castables are both better than those of the silica fume containing castables ; （3） the density of the castable specimens with dense sintered alumina is 4% -6% lower than that of the castable specimens with Jhsed dense corundum so the refractories consumption of one iron runner reduces by 5% by using the tastable with dense sintered alumina, which obviously reduces the cost of refractories.展开更多
A novel porous metal fiber sintered sheet （PMFSS） with a three-dimensional reticulated structure was fabricated by multi-tooth cutting and high-temperature solid-phase sintering process with copper fibers. A uniaxia...A novel porous metal fiber sintered sheet （PMFSS） with a three-dimensional reticulated structure was fabricated by multi-tooth cutting and high-temperature solid-phase sintering process with copper fibers. A uniaxial tensile test was conducted to investigate the effect of fiber length and natural aging factor on the tensile properties of the PMFSS. Results indicated that, under given stress, the increase of fiber length helped reinforce the tensile strength. The elongation of the PMFSS with medium length fiber of 15 mm exhibited the optimal performance, reaching about 13.5%. After natural aging treatment for a month, the tensile strength of PMFSS significantly decreased, but the change of elongation was negligible except for the one with the shortest fiber length of 5 mm, whose elongation was effectively improved. The morphological fracture features of PMFSSs were also characterized.展开更多
基金Key Research and Development Program of Shandong Province(2021CXGC010310)Shandong Province Science and Technology Small and Medium Sized Enterprise Innovation Ability Enhancement Project(2023TSGC0287,2024TSGC0519)+1 种基金Shandong Provincial Natural Science Foundation(ZR2022ME222)National Natural Science Foundation of China(51702187)。
文摘Three types of NdFeB magnets with the same composition and different grain sizes were prepared,and then the grain boundary diffusion was conducted using metal Tb under the same technical parameters.The effect of grain size on the grain boundary diffusion process and properties of sintered NdFeB magnets was investigated.The diffusion process was assessed using X-ray diffractometer,field emission scanning electron microscope,and electron probe microanalyzer.The magnetic properties of the magnet before and after diffusion were investigated.The results show that the grain refinement of the magnet leads to higher Tb utilization efficiency and results in higher coercivity at different temperatures.It can be attributed to the formation of a deeper and more complete core-shell structure,resulting in better magnetic isolation and higher anisotropy of the Nd_(2)Fe_(14)B grains.This work may shed light on developing high coercivity with low heavy rare earth elements through grain refinement.
基金supported by the National Natural Science Foundation of China(Nos.52261037,52088101)the Key research project of Jiangxi Province(No.20203ABC28W006)the Double-Thousand Plan of Jiangxi Province(No.jxsq2023101057).
文摘The low coercivity is the major factor inhibiting the large-scale commercial utilization of Nd-Ce-Fe-B sintered magnets.In this work,we achieved a record-high coercivity of 15.04 kOe in Ga-doped Nd-Ce-Fe-B sintered magnets with 30 wt%Ce replacing Nd,demonstrating enormous potential.The Ga-doped Nd-Ce-Fe-B magnets with higher boron(HB)and lower boron(LB)content are designed.The coercivity of the HB magnet increases slightly from 10.80 to 12.26 kOe after annealing,attributed to the optimized distribution of grain boundary(GB)phases.In contrast,the coercivity of the LB magnet remarkably increases from 8.13 to 15.04 kOe after annealing.Microstructural observations indicate that the narrow GB phase in the as-sintered magnet is rich in Fe,and the strong exchange coupling of adjacent grains resulted in low coercivity.The evolution of Ga-rich phases reveals a potential formation mechanism of the RE_(6)Fe_(13)Ga phase,that is the RE-Fe amorphous phase and REGa phase in the as-sintered magnet combine to form the RE_(6)Fe_(13)Ga phase and RE-Ga amorphous phase during post-sinter annealing(RE:rare earth).Moreover,the GB phase of the annealed magnet transforms into a Fe-lean phase with a thickness of 16.4 nm.Magnetization and demagnetization behavior characterizations reveal that the exchange decoupling of adjacent grains induced by the optimized GB phases is the main reason for the remarkable coercivity enhancement,which is also validated by micromagnetic simulations.
基金Project supported by National Key Research and Development Program of China(2021YFB3500100)National Natural Science Foundation of China(52301068)。
文摘In this work,the effect of the Al addition amount in the TbAl coatings on the grain boundary diffusion proces s(GBDP)of Tb were systematically explored.Direct current magnetron sputtering(DCMS)method was utilized in co-sputtering manner to synthesize the TbAl coatings with certain Tb consumption and various Al addition amount.Results show that the moderate Al addition amount significantly improves the wettability of grain boundary(GB)phases,thereby acquiring more continuous and uniform Tb-rich shells and GB phases between matrix phases,as well as deeper diffusion depth and denser microstructure.The largest increase amplitude of intrinsic coercivity(Hcj)is improved by 78.4%in TbAIdiffused magnet compared to the pure Tb-diffused magnet,while the remanence(Br)is expected to show an overall decreasing tendency accompanied with a slight increase in the decreasing process.However,when the Al addition amount is excessive,magnetic dilution effect is enhanced,and the Tbrich shells and GB phases between matrix phases become fuzzy and even invisible,which in turn deteriorates the magnetic properties of diffused magnets.
基金Project supported by the National Key R&D Program of China(2022YFB3505003,2021YFB3502802)the Natural Science Foundation of Zhejiang Province(LQ23E010001)+3 种基金"Pioneer"and"Leading Goose"R&D program of Zhejiang(2022C01020)Key Research and Development Program of Ningbo City(2023Z093)Kunpeng Plan of Zhejiang ProvinceNingbo Top Talent Program。
文摘Commercial N52 sintered NdFeB magnets were processed by grain boundary diffusion(GBD)with Dy-Co-M(M=Cu,AI)alloys.The coercivity of magnets greatly increase to 17.62 and 18.83 kOe respectively when diffusing Dy_(58)Co_(25)Cu_(17)and Dy_(58)Co_(25)Al_(17)alloys,which are obviously higher than that of Dy58Co42GBD-treated magnet with 16.64 kOe,Further thermal stability studies indicate that the thermal stability of Dy_(58)Co_(25)Cu_(17)and Dy_(58)Co_(25)Al_(17)GBD-treated magnets is further improved compared to the Dy58Co42GBD-treated magnet The results show that th e temperature coefficients of remanence(20-120℃)are reduced from-0.148%/℃to-0.134%/℃and-0.132%/℃by Dy_(58)Co_(25)Cu_(17)and Dy_(58)Co_(25)Al_(17)GBD-treatment,respectively.Besides,the irreversible magnetic flux losses(120℃)for Dy_(58)Co_(25)Cu_(17)and Dy_(58)Co_(25)Al_(17)diffusion magnets are 4.76%and 2.79%,respectively.Microstructural analyses demonstrate that the presence of Cu and Al elements reduces the excessive accumulation of Dy and Co on the surface in the diffusion magnets an d improves the diffusion depth and utilization of Dy and Co.Furthermore,the flow of Co from the triple junction phase to the thin grain boundary phase is promoted,which contributes to the uniform distribution of Co.In addition,the dynamic evolution of the magnetic domain structure during the temperature rise process was studied.This work provides insight into the preparation of high-performance and high-thermal stability magnets.
基金supported by the Korea Institute of Energy Technology Evaluation and Planning and the Ministry of Trade,Industry and Energy of the Republic of Korea(No.20213030030150)by the National Research Foundation of Korea funded by the Korea government(MSIT)(No.RS-2021-NR057434).
文摘In this work,we present an innovative method for fabricating high-performance proton-conductive fuel cells(PCFCs)by combining magnetron sputtering and flashlight sintering(FLS)techniques.BaZr_(0.8)Y_(0.2)O_(3–δ)(BZY20)electrolyte thin-films are successfully prepared by improving the crystallinity while maintaining the stoichiometry.All components of PCFC,Ni-YSZ anode,BZY20 electrolyte and Pt-GDC cathode are fabricated by sequentially sputtering them onto an AAO substrate.Electrolytic sintering is performed at 550 and 650 V conditions using FLS,effectively solving the Ba evaporation problem encountered in conventional thermal sintering methods.XRD analysis confirms that the perovskite structure is retained,and crystallinity is improved in the FLS samples.Furthermore,FE-SEM and EDS analyses confirm the uniform elemental distribution and consistent thickness of the FLS-treated electrolyte.An optimized PCFC unit cell with FLS-treated electrolyte exhibits a peak power density of 200.0 mW cm^(-2) at 500℃ and an ohmic resistance of 376.0 mΩ cm^(-2).These results suggest that the combination of magnetron sputtering and FLS techniques is a promising approach for fabricating highperformance thin-film PCFCs.
基金support from Generalitat Valenciana under Pla Complementari“Programa de Materials Avanc¸ats”,2022(grant number MFA/2022/030)Ministerio de Ciencia,Innovaci´on y Universidades(Spain)(grant number MCIN/AEI/10.13039/501100011033)+1 种基金support from UJI(UJI-2023-16 and GACUJIMC/2023/08)Generalitat Valenciana through FPI Fellowship Program(grant numbers ACIF/2020/294 and CIACIF/2021/050).
文摘This study demonstrates the successful fabrication of solid-state bilayers using LiFePO_(4)(LFP)cathodes and Li_(1.3)Al_(0.3)Ti_(1.7)(PO_(4))_(3)(LATP)-based Composite Solid Electrolytes(CSEs)via Cold Sintering Process(CSP).By optimizing the sintering pressure,it is achieved an intimate contact between the cathode and the solid electrolyte,leading to an enhanced electrochemical performance.Bilayers cold sintered at 300 MPa and a low-sintering temperature of 150℃exhibit high ionic conductivities(0.5 mS cm^(-1))and stable specific capacities at room temperature(160.1 mAh g^(-1)LFP at C/10 and 75.8 mAh g^(-1)_(LFP)at 1 C).Moreover,an operando electrochemical impedance spectroscopy(EIS)technique is employed to identify limiting factors of the bilayer kinetics and to anticipate the overall electrochemical behavior.Results suggest that capacity fading can occur in samples prepared with high sintering pressures due to a volume reduction in the LFP crystalline cell.This work demonstrates the potential of CSP to produce straightforward high-performance bilayers and introduces a valuable non-destructive instrument for understanding and avoiding degradation in solid-state lithium-based batteries.
基金financially supported by the National Natural Science Foundation of China(Nos.52075125 and 52105331)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515010591)Shenzhen Science and Technology Innovation Committee(Nos.JCYJ20210324124203009,JSGG20201102154600003,GXWD20231130103814001,GXWD20220721182229001)
文摘Silver paste is widely used in power electronics as a die-attach material owing to its low-temperature sinterability,high melting point,and excellent electrical and thermal conductivities in sintered joints.However,owing to the mismatch in the coefficient of thermal expansion(CTE)between the joints and chip,the high Young's modulus of sintered silver hinders the mitigation of the high thermal stress generated during the operation of power modules,which increases the susceptibility of sintered joints to cracking,thereby leading to potential failure.This study developed a facile approach to synthesizing bayberry-like Ag microparticles(AgMPs)through the in situ assembly of silver nanorods,resulting in a uniform distribution of nanoscale structures and mesopores on the particle surface.These particles exhibited a high specific surface area of 2.5389 m^(2)·g^(-1),which enhanced theirsintering activity,enabling sintering to occur at 149.7℃.Furthermore,the porous structure of the AgMPs effectively reduced the density of joints formed by sintering AgMP paste,thereby lowering the Young's modulus of the joints.The small grain size and intricate internal substructure of the joints yielded high shear strength,which reached112.50 MPa at 250℃.The Young's modulus could be adjusted,and the pores provided by the AgMPs maintained the Young's modulus within a low range(15.11-29.61GPa),effectively mitigating thermal stress.These new bayberry-like porous AgMPs offer a promising option for die-attach materials in electronic packaging.
基金Funded by the National Natural Science Foundation of China(No.52022072)the Key Research and Development Plan of Jiangxi Province(No.2020ZDYFB0017)。
文摘Low cobalt(Co)WC hard materials were prepared using vacuum sintering.The influences of Co content on the sintering densification behavior,grain growth characteristics,microstructure and mechanical properties of WC hard material were studied.The experimental results show that the addition of a small amount of Co significantly promotes the densification and reduces the sintering temperature.Meantime,the abnormal growth of WC grains was observed.When the sintering temperature is 1300℃and the content of Co is less than 1.0wt%,densed WC/Co hard material with fine grains is obtained.When the content of Co is 1wt%,the relative density,Vickers hardness,and flexural strength of WC material are 98.76±0.17%,24.23±0.41 GPa,and 1376±67 MPa,respectively.When the Co content is 0.25wt%and 0.5wt%,the optimal sintering temperature of the sample is 1350℃.Among them,the relative density,hardness,and flexural strength of WC-0.5wt%Co are 98.79±0.15%,23.44±0.38 GPa,and 1233±85 MPa,respectively.
基金Project supported by the National Key Research and Development Program of China(2021YFB3502902)the Key Research and Development Program of Ningbo(2021Z024)。
文摘Grain boundary diffusion process(GBDP)is a widely used method of increasing the coercivity of sintered NdFeB magnets.In this study,the effects of the GBDP on the bending strength and microhardness of sintered NdFeB magnets and the fracture mode were investigated.Results show that the bending strength of magnets is reduced by pickling and heat treatment and greatly recove rs after heavy rare earth element(Tb)grain boundary diffusion.The pickling and the heat treatment cause a slight decrease in microhardness.Compared with the recovery of the bending strength,the hardness decreases after the GBDP.The fracture mode of bended magnets changes from intergranular to transgranular.This study helps in further improving the mechanical and magnetic properties of sintered NdFeB magnets.
基金supported by the China Scholarship Council (CSC) (No.202206020149)the Academic Excellence Foundation of BUAA for PhD Students,the Funding Project of Science and Technology on Reliability and Environmental Engineering Laboratory (No.6142004210106).
文摘Sintered silver nanoparticles(AgNPs)arewidely used in high-power electronics due to their exceptional properties.However,the material reliability is significantly affected by various microscopic defects.In this work,the three primary micro-defect types at potential stress concentrations in sintered AgNPs are identified,categorized,and quantified.Molecular dynamics(MD)simulations are employed to observe the failure evolution of different microscopic defects.The dominant mechanisms responsible for this evolution are dislocation nucleation and dislocation motion.At the same time,this paper clarifies the quantitative relationship between the tensile strain amount and the failure mechanism transitions of the three defect types by defining key strain points.The impact of defect types on the failure process is also discussed.Furthermore,traction-separation curves extracted from microscopic defect evolutions serve as a bridge to connect the macro-scale model.The validity of the crack propagation model is confirmed through tensile tests.Finally,we thoroughly analyze how micro-defect types influence macro-crack propagation and attempt to find supporting evidence from the MD model.Our findings provide a multi-perspective reference for the reliability analysis of sintered AgNPs.
基金supported by the National Natural Science Foundation of China(Nos.52371188,52061015)Young Talents Program of Jiangxi Provincial Major Discipline Academic and Technical Leaders Training Program(No.20212BCJ23008)+5 种基金Jiangxi Provincial Natural Science Foundation(No.20212BAB214018)the Program of Qingjiang Excellent Young Talents of Jiangxi University of Science and Technology(No.JXUSTQJYX2020003)National College Students Innovation and Entrepreneurship Training Program(No.202110407013)Technology Program of Fujian Province(Nos.2020H6027,2021T3063)Self-deployed Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(No.E055B002)the Key Research Program of the Chinese Academy of Sciences(No.ZDRW-CN-2021–3).
文摘In traditional Nd-Fe-B-based sintered magnets,the composition,role of each element and microstruc-tures have been extensively investigated globally since they were invented in 1983.However,the effects of boron(B)content and post-sinter annealing(PSA)on the microstructure and magnetic properties have been least studied so far and the relative mechanisms are not yet clear.In this paper,we investigated the influence of B on the magnetic performance and microstructure of Nd-Fe-B sintered magnets origi-nally containing copper(Cu),gallium(Ga)and titanium(Ti).It is shown that the intrinsic coercivity has a substantial increment of 2.86 kOe and the remanence has a slight reduction of 0.16 kGs when B content is reduced from 0.980 wt.%to 0.900 wt.%.Moreover,there is a coercivity increment of 27.3%and 65.3%for samples with 0.980 wt.%and 0.900 wt.%B content after PSA,respectively.It is shown that the im-pacts of B content and PSA are significant and their regulation mechanisms are worthwhile to be studied systematically.Furthermore,it is revealed by microstructural analysis that high coercivity of the sample with 0.900 wt.%B after PSA results from the uniform distribution of Ga,Cu,Nd,and the formation of RE 6(Fe,M)14(RE=Pr,Nd,M=Cu,Ga)compound in triple junction phases.The dilution of Fe content in grain boundary phases(GB phases)also plays an important role.It is found out that decrease of the re-manence is mainly due to reduction of the matrix phase and c-axis alignment degree.In this study,we explored a new path to develop Nd-Fe-B-based sintered magnets with high comprehensive properties by novel approaches through varying B content,PSA technique and co-adding trace elements.
基金supported by the National Key Research and Development Program of China(Nos.2021YFF0500300 and 2023YFB3711300)the Strategic Research and Consulting Project of the Chinese Academy of Engineering(Nos.2023-XZ-90 and 2023-JB-09-10).
文摘Establishing a base on the Moon is one of the new goals of human lunar exploration in recent years.Sintered lunar regolith is one of the most potential building materials for lunar bases.The physical,mechanical and thermal properties of sintered lunar regolith are vital performance indices for the structural design of a lunar base and analysis of many critical mechanical and thermal issues.In this study,the HUST-1 lunar regolith simulant(HLRS)was sintered at 1030,1040,1050,1060,1070,and 1080℃.The effect of sintering temperature on the compressive strength was investigated,and the exact value of the optimum vacuum sintering temperature was determined between 1040 and 1060℃.Then,the microstructure and material composition of vacuum sintered HLRS at different temperatures were characterized.It was found that the sintering temperature has no significant effect on the mineral composition in the temperature range of 1030-1080℃.Besides,the heat capacity,thermal conductivity,and coefficient of thermal expansion(CTE)of vacuum sintered HLRS at different temperatures were investigated.Specific heat capacity of sintered samples increases with the increase of test temperature within the temperature range from-75 to 145℃.Besides,the thermal conductivity of the sintered sample is proportional to density.Finally,the two temperatures of 1040 and 1050℃were selected for a more detailed study of mechanical properties.The results showed that compressive strength of sintered sample is much higher than tensile strength.This study reveals the effects of sintering temperature on the physical,mechanical and thermal properties of vacuum sintered HLRS,and these material parameters will provide support for the construction of future lunar bases.
文摘This study investigates full liquid phase sintering as a process of fabrication parts from WE43(Mg-4wt.%Y-3wt.%RE-0.7wt.%Zr)alloy using binder jetting additive manufacturing(BJAM).This fabrication process is being developed for use in producing structural or biomedical devices.Specifically,this study focused on achieving a near-dense microstructure with WE43 Mg alloy while substantially reducing the duration of sintering post-processing after BJAM part rendering.The optimal process resulted in microstructure with 2.5%porosity and significantly reduced sintering time.The improved sintering can be explained by the presence of Y_(2)O_(3)and Nd_(2)O_(3)oxide layers,which form spontaneously on the surface of WE43 powder used in BJAM.These layers appear to be crucial in preventing shape distortion of the resulting samples and in enabling the development of sintering necks,particularly under sintering conditions exceeding the liquidus temperature of WE43 alloy.Sintered WE43 specimens rendered by BJAM achieved significant improvement in both corrosion resistance and mechanical properties through reduced porosity levels related to the sintering time.
基金National Natural Science Foundation of China(51861026)The Graduate Innovation Special Fund of Nanchang Hangkong University(YC2022-011)。
文摘Core-shell MoSi_(2)@Nb powder was prepared by electrostatic layer self-assembly method.The surfactants SDS(CHSO_(4)Na)and CTAB(C_(19)H_(42)BrN)were used to modify the surface of the two particles to make them charged,and the Zeta potential of the suspension was tested by the Zeta potentiometer.Scanning electron microscope,transmission electron microscope and energy dispersive spectrometer were used to characterize the phase,morphology,microstructure and element distribution of synthetic materials.The results show that when the SDS concentration is 2 mmol/L,the CTAB concentration is 3mmol/L and the pH value of Nb suspension is 5,the coating effect is better after secondary cladding.NbSi_(2)phase is found at the interface between Nb and MoSi_(2)after calcination at 200℃ for 2 h in Ar atmosphere,indicating that Nb is highly active and reacts with Si.Core-shell structure is still retained in MoSi_(2)@Nb material after spark plasma sintering at 1450℃ for 2 h under uniaxial pressure of 40 MPa.However,it is found that Nb reacts strongly with MoSi_(2),and most of the Nb phase is reacted.This issue needs to be addressed in subsequent studies.The fracture toughness(K_(IC))of MoSi_(2)@Nb material is significantly improved to 5.75 MPa·m^(0.5)compared with that of MoSi_(2)material(3.32 MPa·m^(0.5)).
基金Project (50930005) supported by the National Natural Science Foundation of ChinaProject (U0834002) supported by the Key Programof NSFC-Guangdong Joint Funds of China+1 种基金Project (LYM09024) supported by Training Program for Excellent Young Teachers withInnovation of Guangdong University, ChinaProject (2009ZM0121) supported by the Fundamental Research Funds for the CentralUniversities of South China University of Technology,China
文摘A procedure of low temperature solid-phase sintering（LTSS） was carried out to fabricate sintered metal fibrous media（SMFM） with high specific surface area.Stainless steel fibers which were produced by cutting process were first plated with a coarse copper coating layer by electroless plating process.A low-temperature sintering process was then completed at about 800 °C for 1 h under the protection of hydrogen atmosphere.The results show that a novel SMFM with complex surface morphology and high specific surface area（0.2 m2/g） can be obtained in this way.The effect of sintering temperature on the surface morphology and specific surface area of SMFM was studied by means of scanning electron microscopy and Brunauer-Emmett-Teller.The damage of micro-structure during the sintering process mainly contributed to the loss of specific surface area of SMFM and the optimal sintering temperature was 800 °C.
基金Projects(50930005,51075155)supported by the National Natural Science Foundation of ChinaProject(20100172110001)supported by PhD Programs Foundation of Ministry of Education of China
文摘Fabrication, characterization and performance of a porous metal-fiber sintered felt （PMFSF） based on multi-tooth cutting and solid-phase sintering were studied. The PMFSF was used as the anodic methanol barrier in a passive air-breathing direct methanol fuel cell to mitigate the effects of methanol crossover. Compared with the commercial SUS316L felt made of bundle-drawn fibers, this self-made PMFSF has larger pore diameter, polarized pore distribution, irregular fiber shape, rougher surface, lower mass flow resistance and evident hydrophobicity. The results reveal that the use of a PMFSF significantly enhances the cell performance since it helps to maintain a balance between the reactant and product management while depressing methanol crossover. The PMFSF with a porosity of 70% yields the highest cell performance at a methanol concentration of 4 mol/L.
文摘MnS growth in sintered steels with admixed Fe, Cu, C and MnS has been investigated by SEM and X-ray diffraction, MnS in Fe-Cu-C-MnS sintered steels in which MnS has been admixed is not stable and MnS growth may be ascribed to sintering between MnS particles or reaction between MnS and Fe, Cu, C elements.
基金supported by National Natural Science Foundation(Grant.Nos.12205056,51972068)Natural Science Foundation of Guangxi Province in China(Grant.No.2021GXNSFBA076003)the UK Engineering and Physical Science Research Council(EPSRC)for funding(EPSRC Grant:Novel high-performance polymeric composite materials for additive manufacturing of multifunctional components,EP/N034627/1).
文摘Polyamide(PA)is a widely utilized engineering polymer,and its thermal and mechanical properties can be further improved by adding nanofillers.However,adding inorganic fullerene-like tungsten disulfide(IF-WS_(2))nanoparticles(NPs)to PA to produce composite precursor powders for additive manufacturing is challenging.Here,we report a novel and cost-effective method for fabricating PA-12 based nanocomposite(NC)powders with fixed/partially encapsulated IF-WS_(2) nanoparticulate fillers utilizing an advanced mixing technique because simple wet mixing(WM)can only attach fillers weakly to the powder surfaces when compared to the proposed method.The resulting nanocomposite powders maintained nearly the original particle size distribution of PA-12.They also exhibited improved rheological properties,melting,and crystallization behaviors compared with those prepared by the WM method.The laser-sintered PA-12 nanocomposite specimens revealed enhanced pow-der thermal stability and higher tensile strengths than pristine PA-12,validating the advantages of the novel technique for the fabrication of polyamide nanocomposite powders and their suitability for utilization in laser sintering additive manufacturing.These results demonstrate that high-performance engineered PA-12 nanocom-posite components can be directly laser sintered,and this technique can potentially be extended to fabricate other engineered polymeric nanocomposite powders.
文摘Three different kinds of corundum aggregates-tabular sintered alumina, dense sintered alumina, and fused dense corundum-were introduced into the silica fume .free or silica fume containing Al2O3 -SiC - C iron runner castables to investigate their influences on the flow ability, linear change on heating, bulk density, apparent porosity, cold strength, hot modulus of rupture, therm, al shock resistance, slag resistance, oxidation resistance as well as wear resistance of Al2O3 - SiC - C iron runner castables. The results show that （ 1 ） compared with the specimens with fused dense corundum, the specimens with dense sintered alumina have equivalent installation property, slag resistance and oxidation resistance, equivalent or even higher cold modulus of rupture, cold crushing strength and hot modulus of rupture, exhibiting better thermal shock resistance and cold wear resistance ; （2） adopting bimodal alumina micropowder LISAL22RABL as well as water reducers ZX2 and ZD2 can well reduce the water requirement of silica fume free castables, solving the problem of deteriorated flow ability resulted from the lack of silica fume; since the lack of silica fume avoids the formation of low melting point liquid, the hot modulus of rupture and the thermal shock resistance of the silica fume free castables are both better than those of the silica fume containing castables ; （3） the density of the castable specimens with dense sintered alumina is 4% -6% lower than that of the castable specimens with Jhsed dense corundum so the refractories consumption of one iron runner reduces by 5% by using the tastable with dense sintered alumina, which obviously reduces the cost of refractories.
基金Projects(51475172,51275180,51375177) supported by the National Natural Science Foundation of ChinaProject(S2013040016899) supported by the Natural Science Foundation of Guangdong Province,ChinaProjects(2013ZM0003,2013ZZ017) supported by the Fundamental Research Funds for the Central Universities,South China University of Technology,China
文摘A novel porous metal fiber sintered sheet （PMFSS） with a three-dimensional reticulated structure was fabricated by multi-tooth cutting and high-temperature solid-phase sintering process with copper fibers. A uniaxial tensile test was conducted to investigate the effect of fiber length and natural aging factor on the tensile properties of the PMFSS. Results indicated that, under given stress, the increase of fiber length helped reinforce the tensile strength. The elongation of the PMFSS with medium length fiber of 15 mm exhibited the optimal performance, reaching about 13.5%. After natural aging treatment for a month, the tensile strength of PMFSS significantly decreased, but the change of elongation was negligible except for the one with the shortest fiber length of 5 mm, whose elongation was effectively improved. The morphological fracture features of PMFSSs were also characterized.
