•Cryogenic properties of the graphene reinforced composites is reported firstly.•The graphene reinforced composites are fabricated by colloidal process.•The maximum fracture toughness is obtained at 1.0 vol% graphene at 77 K.•Fracture mode of the composites changes to transgranular.•Our work could provide an approach to support cryogenic application of graphene.The mechanical properties of the graphene nano-platelets reinforced alumina nanocomposites at cryogenic temperature are reported for the first time. The GNPs/Al2O3 composites are fabricated by a colloidal process. The temperature-dependent increase in hardness is accompanied by a substantial increase in fracture toughness with the temperature decreasing from 293 K to 77 K. The optimum content of GNPs in GNPs/Al2O3 composites is 1.0 vol%. The effect of residual stress on the toughness and fracture mode is discussed on the basis of theoretical calculation and analysis. Cryogenic temperature has contributed to the reinforcing effect of graphene in composites.

•High-efficient combustion synthesis was developed to prepare α-SiAlON:Eu phosphors.•Phosphors exhibited high purity, nice uniformity and good luminescence property.•Distinct impacts of nitrogen pressure and Si particle size were studied.•Two factors play vital roles in phase composition and grain morphology of products.•Appropriate N2 pressure and Si particle size enhanced the luminescence properties.Herein, a facile combustion synthesis strategy (CS) was constructively developed for the highly-efficient preparation of SiAlON based phosphors. Yellow light emitting behavior was endued to the Ca-α-SiAlON ceramic powders by doping of Eu2 +. The Si average particle size and nitrogen pressure were known to play vital roles in the CS reaction. The distinct impacts of these two important processing parameters on the phase composition, microstructure and photoluminescence properties of products were firstly thoroughly studied in the CS system of Ca-α-SiAlON:Eu2 + phosphors. The experimental results demonstrated that the comprehensive properties of as-synthesized phosphors would be evidently promoted by the utilization of appropriate Si particle size and nitrogen pressure, respectively 4 μm and 5 MPa in this system. The phosphors were featured with high phase purity, good state of crystallization, favorable uniformity and equiaxed morphology. A strong yellow emission was peaked at 576 nm under excitation of near-UV or blue light.

SiAlON phosphors doped with rare earths have attracted much attention on the application of light emitting diode (LEDs) benefitting from their outstanding thermal stability, chemical stability and broad emission band properties. In this work, Eu-doped β-SiAlON green phosphors with composition Si5.5Al0.5O0.5N7.5:0.035Eu2+ were prepared by a highly efficient combustion synthesis (CS) method. The effect of comburent ratios (i.e., Si & Al) were systematically investigated by adjusting the starting compositions of reactants. It was confirmed that the ratios of Si and Al reactants had an intense influence on the phase composition, microstructure and photoluminescence properties of as-synthesized phosphors by directly determining the systematic energy in CS. The as-prepared β-SiAlON:Eu2+ phosphors featured with high phase purity, uniform particle size of 3–5 μm, well-crystalline morphology and outstanding luminescent properties of green emission under UV or blue excitation were synthesized with 67.5 wt.% ratio of Si and no Al comburent.Excitation spectra (542 nm) (a) and emission spectra (300 nm) (b) of samples synthesized with various proportions of comburents as indicatedDownload high-res image (146KB)Download full-size image

Despite its unique high efficiency and good environmental compatibility, the water-soluble binder system still encounters problems achieving a desired sintered part via ceramic injection molding because of the poor compatibility and the powder-binder segregation between ceramic powders and binders. The objective of this study was to obtain a sintered part with excellent properties by introducing a small quantity of oleic acid to the surface of zirconia powders before the mixing process. As opposed to many previous investigations that focused only on the rheological behavior and modification mechanism, the sintering behavior and densification process were systematically investigated in this study. With the modified powders, debound parts with a more homogeneous and smaller pore size distribution were fabricated. Also, a higher density and greater flexural strength were achieved in the sintered parts fabricated using the modified powders.

•Fracture toughness of SiCw-Al2O3 composites measured at 77 K was ∼26% higher than that at 293 K.•The calculated compressive stress of SiC whiskers at 77 K was ∼600 MPa.•Whisker reinforcements was enhanced by residual stress at 77 K.•Crack bridging of SiC whiskers at cryogenic temperatures was the dominant reason of enhanced toughness.•SiCw-Al2O3 composite is a promising material for cryogenic applications.The effect of residual stress on whisker reinforcements in SiCw-Al2O3 composites from 293 K to 77 K was investigated. The fracture toughness of SiCw-Al2O3 composites measured at 77 K was ∼26% higher than that at 293 K. The calculated compressive stress of SiC whiskers at 77 K was ∼600 MPa, and the local stress distribution is demonstrated by in-situ Raman spectra and fluorescence spectra. R-Curve behaviors and crack opening displacement profiles were determined to compare the effect of residual stress on crack bridging at different temperatures. The experimental results verified that crack bridging was enhanced by residual stress at 77 K, which made the SiCw-Al2O3 composite to be a promising material for cryogenic applications.

•Micro-/meso-porous SiO2 xerogels were fabricated with low concentration of water.•Physicochemical properties and porous structure of the SiO2 xerogels were evaluated.•Formation mechanism of the micro-/meso-porous SiO2 xerogels was elaborated.In this contribution, hierarchical micro-/meso-porous SiO2 xerogels were successfully prepared through a Stöber methodology coupled with following drying process. The SiO2 xerogels were consisted of nanoparticles of 20–40 nm in size with different contents of water. Fourier transform infrared spectroscopy proved that SiOC2H5 and SiOH groups could be formed in SiO2 xerogels. Further analyses declared that the amount of the SiOC2H5 groups decreased while the concentration of SiOH was firstly increased and then suffered a decline with improving contents of water. Besides, the SiO2 xerogels was endowed with controllable micro-/meso-porous structure. Furthermore, the formation mechanism of the micro-/meso-porous SiO2 xerogels was tentatively put forward. As a consequence, SiO2 xerogels with controllable hierarchical micro-/meso-porous structure could act as the smart material for huge development in catalytic fields.Download high-res image (84KB)Download full-size image

Silicon carbide (SiC) nanostructures are considered as an excellent candidate for field emitters, owning to their versatile superior properties. The field emission with a low turn-on field (Eto) is crucial and highly desired for their practical application. In the present study, SiC nanowires (SiCNWs) were grown on carbon fabrics via the pyrolysis of a polymeric precursor, followed by surface decoration with Au nanoparticles by a sputtering process. The characterizations of their field emission (FE) properties revealed that the Au nanoparticle-decorated SiC nanowires exhibit remarkably enhanced FE performances. Compared to those of the bare counterparts (i.e., without the Au nanoparticle decoration), the Eto of Au decorated SiCNWs was decreased drastically from 2.10 to 1.14 V μm−1. The field enhancement factor (β) of the Au decorated SiCNWs was ca. 6244 ± 50, which is nearly 6 times that of the bare counterparts. The enhanced FE behaviors were mainly attributed to the synergistically increased β and decreased Φ of the SiCNWs induced by Au decoration.

The aim of this study was to understand the phase transformation in yttria-stabilized tetragonal zirconia (Y-TZP) dental ceramic and its effect on slow crack growth (SCG) behavior in oral environment. The SCG behavior of Y-TZP dental ceramic was investigated in air and in water at 37 °C by static fatigue testing on pre-cracked specimens. Additionally, Confocal Raman spectroscopy has been used for the quantitative assessments of phase transformation zones at the crack tip. Environmental metastability of Y-TZP dental ceramic took place a stress/water induced tetragonal – to – monoclinic (t→m) phase transformation and proceed with time. The SCG behavior in water at 37 °C is a result of cracking through a zone of monoclinic material ahead of the crack tip. The crack growth rate is proportional to the probability of successful completion of water/stress induced t→m phase transformation. The Raman spectroscopic assessment provides a new angle of view in understanding the SCG behavior of zirconia dental ceramics in different environments.

Two basic aspects of fracture toughness for 3 mol% yttria-stabilized zirconia ceramics at cryogenic temperatures have been systematically investigated, including crack propagation resistance evaluation and fractographic assessments. By comparison with the obtained R-curve parameters, the calculated shielding stress intensity factors were significantly smaller than the measured ones from the R-curve at various temperatures, and the difference between calculated and measured terms could be minimized if the partial reversibility in the transformation and shear contributions were taken into account, or by assuming that there was some contribution to toughening from microcracking. In addition, the quantitative results of fracture mode were also presented showing a higher intergranular fraction at 77 K than at 293 K, which may be harmful to the fracture toughness.

A systematic study of various spark plasma sintering (SPS) parameters, namely temperature, holding time and applied pressure, was conducted to investigate their effect on the densification, microstructure and mechanical properties of 2Y-TZP ceramics. The obtained results demonstrated that 2Y-TZP can be fully densified at 1300–1600 °C within several minutes. Extending holding time resulted in a more significant grain growth at a higher sintering temperature but no remarkable change in density at a lower sintering temperature. Fully compacted samples could be attained with an applied pressure of 50 MPa at 1300 °C, at a 50 °C lower temperature than in the experiments with an applied pressure of 20 MPa. A critical grain size of 733 nm was revealed, corresponding to the fracture toughness maximum of 9.73±0.38 MPa m1/2. Furthermore, the optimal SPS conditions have been discussed and suggested in order to obtain a good combination of density and favorable fracture toughness.

The dynamic fatigue of 3 mol% Y2O3 stabilized tetragonal zirconia ceramic (3Y-TZP) was assessed at 293 K and 77 K by testing the same batch of specimens in four-point flexure at various stress rates. The crack propagation velocities were also measured using Vickers indentation specimens under dynamic-loading conditions in ambient and cryogenic environment. The slow crack growth (SCG) parameter n at 77 K was larger than that at 293 K. Also, the crack propagation velocity under cryogenic circumstance is much slower than that under ambient circumstance. The experimental results suggest that the 3Y-TZP exhibits a lesser degree of SCG behavior in cryogenic environment. It should be ascribed to two reasons. The negligible effect of stress corrosion and crack tip shielding mechanism induced by temperature. The high SCG resistance in cryogenic environment makes the 3Y-TZP a promising candidate material for long-term service in cryogenic structural applications.

Crack deflection angles and fracture modes were investigated by elaborative observation of 5764 crack deflections, generated at 77 K, 159 K, 293 K and 500 K, in silicon nitride (Si3N4) ceramics. In addition, the effects of grain boundary toughness on crack propagation in Si3N4 ceramics were statistically analyzed based on a two-dimensional, polycrystalline model. The results demonstrated that temperature (77–500 K) had little influence on crack advance, but the change of grain boundary toughness contributed a lot to the change of crack propagation. The distribution of deflection angles varied distinctly and the fraction of transgranular fracture increased when the grain boundary toughness increased.

Flexible field emission (FE) arrays have a wide range of applications in next generation low-cost, lightweight and wearable electronics, roll-up displays, and large-area circuits on curved objects, yet the growth of tapered, high-quality single-crystalline nanostructure-based emitters on flexible substrates with superior FE properties remains challenging and related work is limited. On the other hand, our recent studies have shown that silicon carbide (SiC) 1D nanostructures could meet nearly any stringent requirement for an ideal FE emitter. In this contribution, we report the growth of quasi-aligned, single-crystalline n-type doped (N-doped) 3C-SiC nanoneedles (3C-SiCNNs) on highly flexible carbon fabric via the catalyst assisted pyrolysis of polysilazane. The as-synthesized SiCNNs possess a tapered structure with tiny clear tips with sizes of several to tens of nanometers. The fabricated 3C-SiCNNs have extremely low emission turn-on fields (Eon) in the range of 0.5–1.6 V μm−1 with an average of 1.1 V μm−1, which is comparable to the lowest value ever reported for 1D nanostructure emitters that, however, are grown on rigid substrates. Specifically, our SiCNN arrays on carbon fabric are mechanically and electrically robust, and can withstand mechanical bending up to 500 times and still retain excellent FE performance with Eon of ∼1.1 V μm−1. The field-enhancement factor has been calculated to be 6.5 × 103. The superior FE properties can be attributed to the significant enhancements of the tapered unique morphology and N-doping of the SiCNNs. Calculations based on local density functional theory suggest that nitrogen dopants in the 3C-SiC nanostructure could favor a more localized impurity state near the conduction band edge, which improves the electron field emission. We strongly believe that the present work will provide a new insight into the fabrication of flexible field emission arrays with ultralow turn-on fields enhanced by both shape and doping.

In this work, we adopt a combination of low molecular weight PEG (L-PEG) and high molecular weight PEG (H-PEG) as water-soluble binder to fabricate injection-moulded ceramic parts with large section. The mechanism of the combination of PEGs removal was proposed for the first time. Defect-free near gear parts with large-sized-section (thickness – 16 mm) were successfully fabricated through water extraction (15 h) followed by rapid thermal pyrolysis (4.5 h). It solves the difficulty of fabricating injection-moulded ceramic parts with large section and our approach is energy saving and high-efficiency as compared with conventional thermal debinding. The results demonstrate that our approach of partially water-debinding followed by rapid thermal pyrolysis could solve the problems of conventional thermal debinding, providing an effective route for the production of injection moulded ceramic parts with large section.

Alumina ceramic composites toughened with various contents of fine-sized zirconia particulates were fabricated via cyclic infiltrating pre-sintered alumina preforms with zirconium oxychloride solution and immersion in ammonia solution to induce in situ precipitation. Homogeneous distribution of zirconia throughout the bulk material has been substantiated by line-scan analysis and backscattering images taken from sections with different distances from surface. It was found that a higher drying temperature and increase in infiltration numbers lead to a greater zirconia content and bigger grain size. The hardness of fabricated zirconia toughened alumina composite was firstly improved probably due to the microstructure refining effect, while a further increase in zirconia content results in the decrease of hardness. A significantly higher indentation toughness has been observed for samples containing >10 wt.% zirconia compared with other specimens, which could be attributed to the coarser zirconia grain size and the related greater tendency to transformation into monoclinic phase.Research highlights► Homogeneous ZTA with fine microstructure can be fabricated via cyclic infiltration. ► Drying temperature and infiltration numbers decide zirconia content and grain size. ► Transformation tendency of ZrO2 is probably responsible for the improved toughness.

Solid loading is a critical key to the fabrication of ceramic compacts with high densities via ceramic injection molding. As reported in most previous work, solid loading of ultra-fine alumina feedstock system could be achieved only up to ∼58 vol% with stearic acid (SA) as the surface modification agent. In present work, different from the traditional work in which SA has been introduced just in the powder blending process, we have successfully prepared the feedstock with a much higher solid loading up to ∼64 vol% by a prior ball milling treatment of ceramic powders with a small amount of SA before the traditional blending process. It can be attributed to that SA can be coated homogeneously around the powder surfaces by a chemical reaction induced by ball milling treatment. Highly translucent Al2O3 ceramics have been fabricated, which suggests an alternative route for fabrication of translucent ceramics with high quality.

The mechanical properties of reaction-bonded silicon carbide (RBSC) composites at cryogenic temperatures have been reported for the first time. The results show that the flexural strength and fracture toughness increase from 277.93 ± 23.21 MPa to 396.74 ± 52.74 MPa and from 3.69 ± 0.45 MPa·m1/2 to 4.98 ± 0.53 MPa·m1/2 as the temperature decreases from 293 K to 77 K, respectively. The XRD analysis of the phase composition reveals that there is no phase transformation in the composites at cryogenic temperatures, indicating cryogenic mechanical properties are independent of phase composition. The enhancement of mechanical properties at 77 K over room temperature could be explained by the transition of fracture mode from predominant transgranular fracture to intergranular fracture and stronger resistance to crack propagation resulting from higher residual stress at 77 K. The above results demonstrate that such composites do not undergo similar deteriorations in the fracture toughness as other materials (some kinds of metals and polymers), so it is believed that such composites could be a potential material applied in cryogenic field.Highlights► We reported the mechanical properties of RBSC composites at cryogenic temperatures. ► Fracture strength and toughness increase obviously at 77 K. ► Fracture mode transition and higher stress result in enhanced mechanical properties. ► Such composites could be a potential material applied in cryogenic field.

We have reported the enhanced field emission properties of quasialigned 3C-SiC nanowires synthesized via catalyst assisted pyrolysis of polysilazane. The as-synthesized Al-doped SiC nanowires possess a tapered and bamboo-like structure with clear and tiny tips sized in several to tens of nanometers. The fabricated SiC nanowires have extremely low turn-on fields of 0.55−1.54 V μm−1 with an average of ∼1 V μm−1, which is the lowest one ever reported for any type of SiC emitters. The field-enhancement factor has been calculated to be 2983. The superior FE properties can be clearly attributed to the significant enhancements of the tapered and bamboo-like unique morphology and Al doping of SiC nanowires. Density functional theory calculations suggest that Al dopants in 3C-SiC nanowires could favor a more localized state near the Fermi energy, which improves the electron field emissions. We strongly believe that the present work will open a new insight in the fabrication of field emission sources with ultralow turn-on fields enhanced by both shape and doping.

A technique to directly synthesize highly oriented SiC nanowire arrays on single-crystalline SiC substrates was present in this paper. The great impacts of substrate orientation on the growth habits of nanowires were systematically investigated. It has been found that nanowires can grow along the [1̅102] direction or its’ equivalent ones on SiC (0001) substrates, while nanowires grow along the [101̅0] direction or its’ equivalent ones on SiC (101̅0) and (112̅0) substrates. This technique for the preferred growth of SiC nanostructures can largely improve the quality of SiC nanowire arrays, which have wide applications in the fields of electronic nanodevices, optoelectronic nanodevices, and photocatalytic nanomaterials.

We have demonstrated, for the first time, the fabrication of uniformly blue-colored CoAl2O4−ZrO2 ceramics via a heterogeneous nucleation method. Polyethylene glycol (PEG2000) was used as the dispersant for the ZrO2 powders followed by Al and Co hydrates introduced to the suspension for preparation of coated powders. Then NH3 was added into the suspension to tailor the pH values to favor the heterogeneous nucleation of CoAl2O4 spinels. It is found that heterogeneous nucleation can promote the formation of coloring phases, significantly decrease the volatilization, and improve the uniformity of coloring elements by reducing the mass transferring distance during sintering. It is believed that the method of heterogeneous nucleation could be a facile and cost saving route to facilitate solid-state reaction and guarantee the uniform distribution of new phases within the matrix for the fabrication of colored ceramics.

We report that cylinder-shaped Si3N4 nanowires are not stable and can gradually transform into nanobelts via surface diffusion during high-temperature annealing. We demonstrate that such instability is driven by the requirements for reducing overall surface energy. The resultant nanobelts have the same width-to-thickness ratio, suggesting a stable morphology. A model in terms of surface energy is proposed to explain the formation of such stable morphology, which agrees well with experimental results. Our result suggests that instability could be a limiting factor for high-temperature applications of 1D nanostructures.

In this paper, we report a new technique to manipulate and control the morphology of vapor−liquid−solid (VLS) grown SiC nanowires by varying the pressure of the source species. We demonstrate that the diameter of the nanowires is strongly related to the pressure and pressure variation rate of the source species. SiC nanowires with Eiffel-tower shape, spindle shape, and modulated diameters and periods have been synthesized. In principle, the technique is applicable to other material systems.

The influences of various additives in the slurry on the process of gel-tape-casting were studied. Alumina powder dispersion can be improved by dispersants, and a solids loading of more than 55 vol.% can be reached by using effective dispersant. With the help of plasticizer, the green tape can be bent without cracks. A proper surfactant is employed to reduce the contact angle of slurry on the carrier film and improve wetting. Foams in slurry resulting from the surfactant can be effectively eliminated using defoamer. A green tape with high strength, flexibility and smooth surface has been obtained.

Gelcasting is a very useful technique for producing ceramic green parts with complex shapes. Although it has been successfully applied to ceramic systems consisting of submicron size powders, there is little report on gelcasting of ceramics containing coarse particles. In this work, we report the study on gelcasting of silicon nitride bonded silicon carbide (SNBSC) refractory. It was found that density of SNBSC made by gelcasting is strongly dependent on the solids loading and the organic binder content in slurry. A high solids loading in the slurry is desirable for achieving high density of the materials after sintering. Less amount of monomer is required for gelcasting of this material compared to ultra-fine ceramic powders. Moreover, excessive amounts of monomer could lead to low density after polymer burnout or sintering and low strength for the final products after sintering.

Gelcasting is a very useful technique for producing ceramic green parts with near-net-shapes. Although it has been successfully applied to shape fine ceramic systems where micrometer- and submicrometer-size particles are used as starting powders, there is little report on gelcasting of refractories manufactured by coarse raw materials. In the present paper, dispersion and rheological properties of concentrated suspensions of SiC/Si mixtures with coarse particles (∼350 μm) and their gelcasting processes were discussed. A stable SiC/Si suspension with solids loading up to 70 vol.% was prepared, from which uniform green bodies with complex shapes were successfully gelcast. The performances of green bodies and sintered samples were measured and their microstructures were studied. After nitridation of the gelcast components at 1450 °C for 10 h in 0.1 MPa nitrogen atmosphere, the bulk density of 2.61 g cm−3 and flexural strength of 55.4 MPa were obtained.

Herein, we put forward a simple combustion synthesis strategy for the highly efficient preparation of Eu-doped Ca-α-SiAlON yellow phosphors with different composition of Ca(m/2−x)EuxSi12−m-nAlm+nOnN16−n. The as-synthesized phosphors were endowed with outstanding photoluminescence behavior of yellow emission peaking at ~580 nm under excitation of near-ultraviolet (UV) or blue light. In the designed experiments, products with different compositions, which were determined by the varying m and n values, were obtained by adjusting the proportion of starting reactants. Further, the dependence of composition on the overall properties of products was systematically studied. It was found that the m and n values could have distinct impact on the phase composition, microstructure and photoluminescence properties of as-synthesized phosphors. The most prominent enhancement of spectral intensity was achieved in the sample with composition of m=1.5 and n=0.8 in this research system. The resultant Ca-α-SiAlON:Eu2+ phosphors were simultaneously featured with high purity, favorable uniformity and equiaxial morphology. A continuous red shift phenomenon in emission wavelength with the increase of m value and an inverse blue shift with the increase of n value were both observed and rationally uncovered.

ZTA ceramics containing 20 wt% ZrO2 were fabricated at different sintering temperatures (1450, 1500 and 1550 °C) by SPS and HP processes, respectively. The influence of sintering process on the mechanical properties of ZTA ceramics at 298 K and 77 K was investigated. It can be seen that the bending strength and fracture toughness of samples prepared by the two processes both improved at cryogenic temperature. The stress-induced martensitic transformation toughening mechanism was confirmed by the in-situ Raman technique. The tetragonal ZrO2 would be even more easy to transform because of the residual stress generated when temperature decreased from 298 K to 77 K. Therefore, the transformation toughening effect would become stronger, result in the increase of mechanical properties.

Silicon carbide (SiC) nanostructures are considered as an excellent candidate for field emitters, owning to their versatile superior properties. The field emission with a low turn-on field (Eto) is crucial and highly desired for their practical application. In the present study, SiC nanowires (SiCNWs) were grown on carbon fabrics via the pyrolysis of a polymeric precursor, followed by surface decoration with Au nanoparticles by a sputtering process. The characterizations of their field emission (FE) properties revealed that the Au nanoparticle-decorated SiC nanowires exhibit remarkably enhanced FE performances. Compared to those of the bare counterparts (i.e., without the Au nanoparticle decoration), the Eto of Au decorated SiCNWs was decreased drastically from 2.10 to 1.14 V μm−1. The field enhancement factor (β) of the Au decorated SiCNWs was ca. 6244 ± 50, which is nearly 6 times that of the bare counterparts. The enhanced FE behaviors were mainly attributed to the synergistically increased β and decreased Φ of the SiCNWs induced by Au decoration.

Flexible field emission (FE) arrays have a wide range of applications in next generation low-cost, lightweight and wearable electronics, roll-up displays, and large-area circuits on curved objects, yet the growth of tapered, high-quality single-crystalline nanostructure-based emitters on flexible substrates with superior FE properties remains challenging and related work is limited. On the other hand, our recent studies have shown that silicon carbide (SiC) 1D nanostructures could meet nearly any stringent requirement for an ideal FE emitter. In this contribution, we report the growth of quasi-aligned, single-crystalline n-type doped (N-doped) 3C-SiC nanoneedles (3C-SiCNNs) on highly flexible carbon fabric via the catalyst assisted pyrolysis of polysilazane. The as-synthesized SiCNNs possess a tapered structure with tiny clear tips with sizes of several to tens of nanometers. The fabricated 3C-SiCNNs have extremely low emission turn-on fields (Eon) in the range of 0.5–1.6 V μm−1 with an average of 1.1 V μm−1, which is comparable to the lowest value ever reported for 1D nanostructure emitters that, however, are grown on rigid substrates. Specifically, our SiCNN arrays on carbon fabric are mechanically and electrically robust, and can withstand mechanical bending up to 500 times and still retain excellent FE performance with Eon of ∼1.1 V μm−1. The field-enhancement factor has been calculated to be 6.5 × 103. The superior FE properties can be attributed to the significant enhancements of the tapered unique morphology and N-doping of the SiCNNs. Calculations based on local density functional theory suggest that nitrogen dopants in the 3C-SiC nanostructure could favor a more localized impurity state near the conduction band edge, which improves the electron field emission. We strongly believe that the present work will provide a new insight into the fabrication of flexible field emission arrays with ultralow turn-on fields enhanced by both shape and doping.