Core-shell Structured Particles Research Articles

Effect of structural design of core-shell particles and core-shell-shell particles on PVDF dielectric energy storage composite films

The structure of added fillers can be used to regulate the balance between dielectric properties and energy storage efficiency in composite materials for dielectric energy storage. In this study, acid-treated carbon nanotubes (CNT-OH) were encapsulated with silicon dioxide (SiO2) and polydopamine (PDA) to create two types of core-shell particles with different structures. Composite films, namely CNT-OH@SiO2/PVDF and CNT-OH@SiO2@PDA/PVDF, were prepared using a solution casting method. The core-shell particles were characterized through TEM, SEM, and XPS, while the composite films microstructure was examined using XRD and SEM. By comparing the effects of different core-shell fillers and their amounts on the dielectric properties and energy storage efficiency, it was observed that the addition of CNT-OH@SiO2@PDA facilitated the transformation of the PVDF matrix crystalline phase from α and γ phases to the β phase. This resulted in an increased dielectric constant while maintaining a low dielectric loss in the composite film. Specifically, the PVDF composite films with 2.0 wt.% of CNT-OH@SiO2 and 2.0 wt.% CNT-OH@SiO2@PDA exhibited dielectric constants of 11.29 and 11.86 at 1000 Hz, with dielectric losses of 0.0129 and 0.0109, respectively. Furthermore, both composite films demonstrated enhanced energy storage density. At 0.5 wt.% of CNT-OH@SiO2 and CNT-OH@SiO2@PDA, the breakdown field strengths were 156.76 kV/mm and 172.30 kV/mm, the energy storage densities were 1.77 J/cm3 and 2.17 J/cm3, and the charge-discharge efficiencies were 55.0% and 56.8%, respectively. The core-shell particle structure developed in this study offers a novel approach for designing dielectric energy storage composite materials.

Solution-Based Synthesis of Cathode Materials for Lithium Ion Batteries

Electrochemical energy storage is expected to make an important contribution to combating global climate change, e.g. via electric vehicles and stationary storage. Currently, lithium-ion batteries are the most prominent candidate for rechargeable batteries to be used in this respect. However, performance of lithium-ion batteries is strongly influenced by the active material at the cathode side, which is often a complex multi-metal oxide. Such a material's properties are dictated by the fabrication method. The design of an appropriate synthesis strategy is then logically also aimed at optimal material properties. However, the design strategy should also take into account green chemistry principles, such as atom economy and energy efficiency. Solution-based routes towards (multi)metal oxide synthesis provide a large diversity of routes and therefore a strong versatility in their design. In this contribution, two groups of routes will be discussed: aqueous solution-gel and coprecipitation routes. The aqueous solution-gel route encompasses three stages: precursor solution synthesis, in which the metal ions are stabilized by complexation with carboxylate ligands, gelation to form an amorphous precursor gel in which the metal ions are homogeneously mixed, and decomposition into the final metal oxide. In this route, precipitation is to be avoided, since it would introduce inhomogeneities. In contrast, the coprecipitation route is entirely based on the formation of insoluble solid precipitates, which can be further transformed in a solid state reaction into lithiated compounds. Whereas solution-gel is ideally suited for complex metal oxides with a large number of metal ions, coprecipitation of many different metal ions at the same time can be challenging. On the other hand, the atom efficiency of the latter can be very high which is attractive for upscaling. Certainly, both of these routes have a high versatility because of the flexibility in compositions (starting products, solvents, ...) and conditions (temperature, time, ...) during the synthesis.In this presentation, an overview will be given of the application of these synthesis routes to the synthesis and/ or surface modification of various cathode materials for lithium ion batteries, which are of general interest and are ranging from Ni-rich compositions of NMC (NMC622), to lithium manganese rich NMC and to Co-free compositions such as LNMO and Li rich LMO. First, the classic NMC 622 is surface modified by a TiOx via a sol-gel route, leading to the formation of core-shell structured particles. The presence of TiOx improved the rate performance and electronic conductivity of the cathode material, and led to a higher initial coulombic efficiency and lower ageing rates in full cells with LTO. Furthermore, layered Li-rich/Mn-rich (LMR-)NMC, which is interesting because of its remarkably high specific discharge capacity was synthesized by two different routes, solution-gel and coprecipitation. It was shown that the solution-gel material in this case had a retarded voltage fade but larger capacity fade than the coprecipitated material. This was correlated to differences in particle morphology and the presence of Ni-enriched spinel-type surface layer. Furthermore, the effect of Sn4+ substitution in the LMR-NMC was investigated. The solubility of Sn4+ substituting for Mn4+ turned out to be a limiting factor here, and could not prevent the voltage fade sufficiently. Finally, we turned to Co-free cathode compositions. LiNi0.5Mn1.5O4-delta was prepared by an aqueous solution-gel route, which allowed to tune the particle size (a few µm versus 70 µm) and morphology. This led to optimized initial discharge capacity and its retention. Finally, Ti4+ substituted Li2MnO3 was synthesized as well via an aqueous solution-gel method. The substitution was shown to improve the structural stability, and galvanostatic cycling hinted at a delayed oxygen release during the first 10 cycles, however, followed by pronounced oxygen redox activity.In conclusion, solution-based routes are highly versatile and provide many opportunities to synthesize cathode materials for lithium ion batteries.

Core-shell structure with reversible composition of Al-Bi immiscible alloy particles prepared by pulsated orifice ejection method

The effect of different step time on the liquid phase separation process and macroscopic morphology of Al-60 wt% Bi immiscible alloys were investigated by pulsated orifice ejection method (POEM). The results show that the decrease of the step time will accelerate the solidification and growth of the minor-phase globule in the liquid phase separation process, which will have a significant effect on the macroscopic morphology after solidification. The Al-60 wt% Bi core–shell structure particles with Al as the core and Bi as the shell were successfully prepared when the step time was 100 μs. In the same experiment, Al-60 wt% Bi core–shell structure particles with Bi as the core and Al as the shell at a step time of 50 μs were successfully prepared. The same particle size and the same overheat of Al-60wt.%Bi particles with reversed core and shell composition were achieved under containerless solidification conditions.

Sodium alginate/chitosan-coated TiO2NPs hybrid fiber with photocatalytic self-cleaning property, UV resistance and enhanced tensile strength

SA/CS-coated TiO2NPs hybrid fibers with photocatalytic self-cleaning properties, UV resistance and enhanced tensile strength were successfully prepared by adding CS-coated TiO2NPs to SA matrix. The FTIR and TEM results demonstrate the successful preparation of CS-coated TiO2NPs core-shell structured composite particles. SEM and Tyndall effect results showed that the core-shell particles were uniformly dispersed in the SA matrix. When the content of Core-shell particles increased from 0.1 to 0.3 wt%, the tensile strength of SA/CS-coated TiO2NPs hybrid fibers increased from 26.89 to 64.45 % compared with SA/TiO2NPs hybrid fibers. The SA/CS-coated TiO2NPs hybrid fiber (0.3 wt%) exhibits excellent photocatalytic degradation performance, achieving a 90 % degradation rate for the RhB solution. And the fibers also exhibit outstanding photocatalytic degradation performance towards various dyes and stains commonly encountered in daily life, including methyl orange, malachite green, Congo red, coffee and mulberry juice. The UV transmittance of the SA/CS-coated TiO2NPs hybrid fibers decreased significantly from 90 % to 75 % with the increase in core-shell particle addition, and correspondingly, the UV absorption capacity increased. The SA/CS-coated TiO2NPs hybrid fibers prepared lay the groundwork for potential applications in various fields, including textiles, automotive engineering, electronics and medicine.

Preparation of Al52Sn28Bi20 particles with morphology-controlled core–shell structure by the pulsated orifice ejection method

The core–shell structure is commonly found in immiscible alloy droplets, but their formation route is hindered by the uncontrollable thermal history of droplets prepared through traditional methods. To address this issue, the pulsated orifice ejection method was used to prepare core–shell structure particles with a consistent thermal history. Our study identified a formation route for core–shell structures, wherein the second phase of the outer layer of the particle migrates and coalesces to form the core. It was found that the step time of the pulsated orifice ejection method strongly influenced the final morphology. These findings have significant implications for understanding the formation mechanism of core–shell structures.

A quasi-implicit and coupled multiscale scheme for simulating combustion of pellets of core-shell structured intermetallic particles

A comprehensive theoretical and computational framework is developed to simulate combustion and flame propagation in a packed pellet of core-shell structured intermetallic energetic particles. A coupled multiscale approach is adopted, in which the atomic diffusion process in micron-scale particles is strongly linked to the macro-scale energy transport in the pellet. Species transport equations are solved for the core-shell structured particle, with the diffusivity treated as a temperature-dependent parameter. The energy equation is solved for the pellet, with the source term governed by the evolution of species concentrations in the core-shell structured particle. A quasi-implicit numerical scheme is developed to ensure stability and a generalized Crank-Nicholson scheme is adopted to tune the degree of implicitness and control the order of temporal accuracy. Further, the temperature dependence of properties and phase change of materials are considered. The theoretical and computational framework is applied to simulate combustion of pellets with Ni/Al core-shell particles of diameters in the range of 10–100 µm. An attempt is made to simulate experiments as closely as possible and the predictions are compared with the available experimental data. Suitable diffusivity model parameters that best describes the experimental data are identified. Parametric studies are conducted to study the effects of particle size, interstitial gas, and pressure on the combustion velocity. Results provide novel insights on the combustion process and directions for future studies.

In-flame soot structure of a jet fuel with 24% aromatics in a small-bore optical compression-ignition engine

This study applies a multi-location soot sampling method in a small-bore optical compression ignition engine to show in-flame particle evolution of a surrogate jet fuel with 24% aromatics (AR24) and a conventional diesel fuel. Four soot sampling probes are installed on the piston-bowl wall with 60° spacing angles for simultaneous sampling from the same firing cycle. These sampling locations represent a jet-wall impingement point (JW), an up-swirl point (US), a down-swirl point 1 (DS1) and a down-swirl point 2 (DS2) along the sooting flame path identified by high-speed soot luminosity images and planar laser induced incandescence (PLII) images. The sampled soot particles are examined with transmission electron microscope (TEM) and the images are post processed for the analysis of morphology. The results showed both fuels produce a large amount of small soot aggregates at JW point due to fuel-rich mixtures while AR24 soot aggregate number count is much less than diesel, indicating less soot formation for AR24. They grow as the flame travels along the bowl wall through aggregation, which is more significant at DS1 point than that of US point. Simultaneously, some small soot aggregates disappear due to oxidation, which is more significant at US point. As the sooting flame reaches DS2 point, only large aggregates with compact structures survived intense oxidation. The soot sampling performed for high resolution TEM and internal structure analysis of AR24 showed that the core-shell particle structure becomes clearer and the carbon-layer fringe-to-fringe gap decreases during the flame penetration, indicating the soot oxidation continued. From the results, the in-flame soot evolution is characterised by high formation of small aggregates at JW point, simultaneous aggregation and oxidation at US and DS1 point with the latter more prone to aggregation, and significant oxidation at DS2 point.

One-pot solvothermal synthesis of S-doped LiMn0.5Fe0.5PO4@N/S-doped C core-shell structured composites for lithium-ion batteries

A self-assembled core-shell structured S-doped LiMn0.5Fe0.5PO4@N/S-doped C composites were prepared by a convenient one-step solvothermal process. The glucose-derived carbon microspheres are coated with LiMn0.5Fe0.5PO4 particles and form secondary particles of core-shell structure. Thioacetamide (TAA) and cetyltrimethylammonium bromide (CTAB) regulate the growth of LiMn0.5Fe0.5PO4 particles and provide N and S atoms for doping the composites. Electrochemical tests show that appropriate additions of TAA and CTAB can improve the discharge capacity of LiMn0.5Fe0.5PO4 cathodes. The [email protected] delivers high specific discharge capacities of 166.83 mAh·g−1 (0.1 C) and 96.47 mAh·g−1 (10 C).

Liquid-liquid phase separation reduces radiative absorption by aged black carbon aerosols

Black carbon aerosols absorb radiation and their absorptive strength is influenced by particle mixing structures and coating compositions. Liquid-liquid phase separation can move black carbon to organic particle coatings which affects absorptive capacity, but it is unclear which conditions favour this redistribution. Here we combine field observations, laboratory experiments, and transmission electron microscopy to demonstrate that liquid-liquid phase separation redistributes black carbon from inorganic particle cores to organic coatings under a wide range of relative humidity. We find that the ratio of organic coating thickness to black carbon size influences the redistribution. When the ratio is lower than 0.12, over 90% of black carbon is inside inorganic salt cores. However, when the ratio exceeds 0.24, most black carbon is redistributed to organic coatings, due to a change in its affinity for inorganic and organic phases. Using an optical calculation model, we estimate that black carbon redistribution reduces the absorption enhancement effect by 28–34%. We suggest that climate models assuming a core-shell particle structure probably overestimate radiative absorption of black carbon aerosols by approximately 18%.

Lubrication behaviors of core-shell structured particles formed by whey proteins and xanthan gum

Whey protein isolate and xanthan gum were used to form pure whey protein particles at 75 °C (WPI-75) or composite particles prepared at 75 °C (WPI/XG-75) and 95 °C (WPI/XG-95) to investigate the relationship between the particle characteristics and lubrication properties of biopolymer particles. A spherical core-shell structure was formed in the composite particles, wherein WPI/XG-75 showed more complete coating by XG than WPI/XG-95. WPI/XG-75 presented a similar particle size to WPI-75, while a much larger particle size was observed for WPI/XG-95. The composite particles showed higher surface hydrophobicity (H0) than WPI-75, with WPI/XG-75 the highest. AFM results indicated the possibility of clustering of WPI/XG-75 particles. Tribology results showed that WPI/XG composite particles exhibited a rather higher friction coefficient than WPI-75 during the initial sliding, due to the particles clustering or the large particle size. However, similar or even lower friction was observed with WPI/XG-95 than WPI-75 when the sliding speed was over 0.5 mm/s. Particles with or without XG showed different lubricating behaviors with the presence of artificial saliva. WPI/XG-95 was also found to exhibit excellent fat replacing function in the o/w emulsion. Thus, particles with core (WPI)-shell (XG) structure are very promising in fat replacement. However, particle size and particle clustering issue need to be further improved.

Formation mechanism of CuNiAl-rich multi-structured precipitation and its effect on mechanical properties for ultra-high strength low carbon steel obtained via direct quenching and tempering process

Ultra-high low carbon baintic steel strengthened by CuNiAl-rich multistructured particles was studied in this work. The influence of direct quenching and tempering (DQ-T) process on microstructural transformation and precipitation behavior of CuNiAl-rich particles were investigated. The high-density dislocations formed in DQ process provide a large number of nucleation sites for the CuNiAl-rich particles. According to the results of phase field method simulation, the coarsening mechanisms of CuNiAl-rich particles included merger mechanism and Ostwald maturation mechanism. The formation of 9R–B2 core-shell structural CuNiAl-rich particles was owing to the inverse concentration gradient diffusion of Cu between particles with different Cu content. The yield strength was 1228 MPa, because of the co-precipitation of 9R–B2 core-shell structural particles with ∼12.5 nm and B2-ordered particles with ∼3.4 nm. The impact absorbed energy was 44.2J at −40 °C. The small grain size contervailed for toughness reduction from co-precipitation.

Connectedness percolation in the random sequential adsorption packings of elongated particles.

Connectedness percolation phenomena in the two-dimensional packing of elongated particles (discorectangles) were studied numerically. The packings were produced using random sequential adsorption off-lattice models with preferential orientations of the particles along a given direction. The partial ordering was characterized by the order parameter S, with S=0 for completely disordered films (random orientation of particles) and S=1 for completely aligned particles along the horizontal direction x. The aspect ratio (length-to-width ratio) of the particles was varied within the range ɛ∈[1;100]. Analysis of connectivity was performed assuming a core-shell structure of the particles. The value of S affected the structure of the packings, the formation of long-range connectivity, and the behavior of the electrical conductivity. The effects can be explained by taking accounting of the competition between the particles' orientational degrees of freedom and excluded volume effects. For aligned deposition, anisotropy in the electrical conductivity was observed with the values along the alignment direction σ_{x} being larger than the values in the perpendicular direction σ_{y}. Anisotropy in the localization of the percolation threshold was also observed in finite-sized packings, but it disappeared in the limit of infinitely large systems.

Microstructural evolution and mechanical properties of the friction stir welded Al[sbnd]Cu dissimilar joint enhanced by post-weld heat treatment

Dissimilar butt joint of pure aluminum and commercially pure copper was prepared using friction stir welding (FSW) process and subsequent post-weld heat treatment (PWHT) was also performed to improve the mechanical properties of the joints. The microstructural evolution of the intermetallic compounds (IMCs) was principally characterized by optical microscopy (OM), scanning electron microscopy equipped with energy diffraction spectrometer (SEM-EDS), X-ray diffraction (XRD), electron backscatter diffraction (EBSD) and high-resolution transmission electron microscopy (HRTEM). The results suggested that the IMCs layer played a critical role on the metallurgical bounding. A 1.9 μm thickness of AlCu IMCs layer successfully achieved by the post annealing treatment which was composed of dominated Al2Cu phase with average grain size of 0.72 μm and small proportion of Al4Cu9 phase. This thin IMCs layer with very fine grain structure and further refined Al matrix in stir zone promoted the improvement of total joint strength from 79% towards 95% of Al base material. Moreover, the failure mode of the FS Welds converted into the mixed fracture from original brittle fracture. While the very low strength with high brittleness of the joint was mainly attributed to the thicker thickness of IMCs layer containing coarse Al2Cu grains with average grain size of 2.6 μm, which produced by the solution treatment. It was established that the existence of the IMCs layer was the main contribution to the distinct rise in microhardness. In addition, the high fraction of high angle grain boundaries of Al2Cu phase indicated the occurrence of grain bulging mechanism through grain boundary migration during annealing treatment. The grain growth behavior of IMCs layer revealed that a core-shell structured AlCu-Al4Cu9 particles probably occurred in the Al2Cu matrix.

Microstructure and magnetic properties of SiO2/FeCoNiSi0.25 high-entropy alloy with a core/shell structure

This study aimed to improve the mechanical and soft magnetic properties of HEAs with core–shell structure. Core-shell structured SiO2 particles and interparticle insulative SiO2/FeCoNiSi0.25 soft cores were prepared by in situ chemical deposition combined with the following spark plasma sintering (SPS) process. The structure of the high-entropy alloy (HEA) formed was a single face-centered-cubic solid-solution phase. The Ms and Hc of FeCoNiSi0.25 HEA powders without and with SiO2 shell were 103.41 emu/g and 85.96 emu/g, and 177.60 Oe and 184.12 Oe, respectively. On the contrary, the Ms and Hc of the bulk FeCoNiSi0.25HEAs (SPS-ed) without and with SiO2 shell were 135.92 emu/g and 142.8 emu/g, and 5.92 Oe and 167.83Oe, respectively. The magnetic properties of SiO2/FeCoNiSi0.25 HEAs (SPS-ed) were significantly stronger than those of SiO2-free FeCoNiSi0.25, indicating that the coupling phenomenon between magnetic crystals existed.

Thin Ta/Ta oxide core-shell nanoparticle film size-dependent energy structure

The paper presents the research of thin films, consisting of spherical monodisperse Ta particles. For different samples particle sizes varied from 1.3 nm to 5.8 nm. The films were also exposed to the atmosphere for oxidation, which resulted in formation of a core-shell particle structure, where core was metal and shell was Ta oxide (Ta2O5). Dependency of bandgap Egap and valence band offset (VBO) on particle size has been investigated for the structure by using the X-ray photoelectron spectroscopy (XPS) and reflected electron energy loss spectroscopy (REELS) methods. We have found, that Egap decreases from 4.72 eV to 4.47 eV whereas VBO decreases from 3.50 eV to 2.95 eV with increasing the particle size. A new method of a fine regulation of the electronic structure is suggested, particularly for the application in ultraviolet (UV) photodetector design for low-lying nuclear and electron transitions detection.

Experimental investigation into the number, micromorphology, functional group composition, and oxidation activity of particles from diesel engine with biodiesel blend

Biodiesel is a promising alternative clean fuel for vehicles. In this paper, comprehensive particulate characteristics, including the particle number (PN), particle mass (PM), particle size distribution, particle micromorphology, chemical functional groups and particle oxidation activity from biodiesel blend B20 (20% biodiesel and 80% diesel by volume), were investigated based on a diesel bus using a heavy chassis dynamometer bench. Results showed that B20 could reduce the PN by 18.8% and the PM by 27.3%. The reduction efficiency of B20 on the accumulation mode particles was higher than that of the nucleation mode ones, which were 43.2 and 7.6%, respectively, thereby causing the proportion of the nucleation mode particles in B20 to increase from 54 to 66% in comparison with that of D100 (pure diesel). In terms of the particle micromorphology, the average fractal dimension of the particles from B20 was higher than that of D100, indicating that the particles from B20 were more compact. The proportion of typical core–shell structure particles in the basic carbon particles of B20 was higher than that of D100, and the coincidence degree between particles was also higher for B20; additionally, B20 preferred to produce basic carbon particles with a regular spherical shape. The graphitization degree of the particles increased with increasing oxidation temperature, but the lattice defect degree decreased. The Raman analysis reflected that the particles of B20 had a higher lattice defect degree but a lower graphitization degree compared with the particles of D100. The ratio of O/C, as well as the sp3/sp2 ratio of the B20 particles, were higher than those of the D100 particles, also indicating that more defects were present in the B20 particles. The particles from B20 exhibited higher oxidation activity in comparison with the particles from D100.

Hollow Mesoporous Microspheres Coating for Super-Hydrophobicity Wood with High Thermostability and Abrasion Performance.

Super-hydrophobic phenomena generally exist in nature, and wood can also obtain hydrophobicity by specific processing on the surface, being like the construction of microscale rough surface or decoration with low surface energy materials. In this research, the formation of hydrophobic layers on wood surface was investigated without breaking the wood’s original structure. The core-shell structure particles were prepared by penetrating orthosilicate and polystyrene into the hollow mesoporous microsphere structure with tetrahydrofuran. A wood sample was coated with polydimethylsiloxane (PDMS) resin layer to enhance the adhesion of nano and micron hollow mesoporous microsphere on its surface. According to the surface structure of super-hydrophobic subjects in nature, the nano and micron hollow mesoporous microsphere were sprayed with different ratios several times to form a hydrophobic surface. The water contact angle could reach 150°, revealing that the hydrophobic behavior of the nano and micron hollow mesoporous microsphere coating was achieved. The microstructures of wood samples were examined by the scanning electron microscopy, and the chemical functional groups were investigated by the Fourier transform infrared; both verified that the hydrophobic surface was successfully coated. The thermogravimetric examination revealed the improved thermal stability of the hydrophobic wood. The scratch test was used to measure the abrasion resistance of the nano and micron hollow mesoporous microsphere coatings on wood surface. It was suggested that the nano and micron hollow mesoporous microsphere coating was an effective method to fabricate extremely hydrophobic wood products.

Synthesis of Core-Shell Micro/Nanoparticles and Their Tribological Application: A Review.

Owing to the diverse composition, adjustable performance, and synergistic effect among components, core–shell micro/nanoparticles have been widely applied in the field of tribology in recent years. The strong combination with the matrix and the good dispersion of reinforcing fillers in the composites could be achieved through the design of core–shell structural particles based on the reinforcing fillers. In addition, the performance of chemical mechanical polishing could be improved by optimizing the shell material coated on the abrasive surface. The physical and chemical state of the core–shell micro/nanoparticles played important effects on the friction and wear properties of materials. In this paper, the synthesis methods, the tribological applications (acted as solid/liquid lubricant additive, chemical mechanical polishing abrasives and basic units of lubricant matrix), and the functionary mechanisms of core–shell micro/nanoparticles were systematically reviewed, and the future development of core–shell micro/nanoparticles in tribology was also prospected.

Shielding composites for neutron and gamma-radiation with Gd2O3@W core-shell structured particles

Particles of micron gadolinium oxide core and nano tungsten shell were introduced into aluminum matrix to prepare neutron and gamma ray co shielding materials. The neutron and gamma ray simulation results show that the absorption efficiency for neutron and the half value layers for primary and secondary gamma ray meet the shielding application. Morphology of core-shell structures and composites have been analyzed using scanning electron microscopy. Compared with the original particles reinforced aluminum matrix composite, tensile strength is improved by the core-shell structure particles. The tensile fracture morphology shows that the main reason for the transgranular fracture of composite is that the grain boundary Gd2O3@W particles prevent the crack growth.

Mechanical properties optimization of Si3N4 ceramics by in-situ introduction of core-shell structural W-Fe5Si3

It is one inevitable problem that optimizing properties of Si3N4 ceramics by introducing second phase would produce thermal mismatch stress, which may lead to interfacial bonding and strength deterioration. In this work, a novel strategy for regulating the residual thermal stress and inhibiting the interfacial debonding in Fe5Si3/Si3N4 ceramics was proposed, which results in the simultaneous increase of strength and toughness of Si3N4 ceramics. Instead of Fe5Si3 particle, the core-shell structural W-Fe5Si3 particles were in situ generated in the Si3N4 matrix by introducing a new WSi2/FeSi2 powder directly. The maximum principal stress, residual radial and tangential stress around the core-shell structural W-Fe5Si3 and Fe5Si3 particle were compared by using the finite element method. The W core inhibits the radial contraction of the Fe5Si3 shell during the cooling process and alters the residual thermal stress distribution. Both the Griffith fracture equation and Lange's energy model indicate that the core-shell structural W-Fe5Si3 inhibits the interfacial debonding, which is consistent with the experiment result. As a result, with the increase of WSi2/FeSi2 addition from 0 to 1 wt%, the fracture toughness of Si3N4 ceramics increases from 7.1 to 7.7 MPa m1/2, and the strength improves from 1016 to 1173 MPa.