The synthesis, microstructure, and properties of high purity dense bulk Mo2TiAlC2 ceramics were studied. High purity Mo2TiAlC2 powder was synthesized at 1873 K starting from Mo, Ti, Al, and graphite powders with a molar ratio of 2:1:1.25:2. The synthesis mechanism of Mo2TiAlC2 was explored by analyzing the compositions of samples sintered at different temperatures. It was found that the Mo2TiAlC2 phase

A new class of high-entropy M3B4 borides of the Ta3B4-prototyped orthorhombic structure has been synthesized in the bulk form for the first time. Specimens with compositions of (V0.2Cr0.2Nb0.2Mo0.2Ta0.2)3B4 and (V0.2Cr0.2Nb0.2Ta0.2W0.2)3B4 were fabricated via reactive spark plasma sintering of high-energy-ball-milled elemental boron and metal precursors. The sintered specimens were ∼98.7% in relative

Hybrid improper ferroelectric Ca3Ti2O7 and Ca3Ti19Ru0.1O7 ceramics were successfully synthesized by conventional solid-state reaction method. Two strongest diffraction peaks located around 2θ = 33° shifted towards the lower angle region with Ru substitution, reflecting structure variation. Grain growth and higher oxygen vacancy concentration after doping resulted in a reduction in the coercive field

The in situ nano Ta4HfC5 reinforced SiBCN-Ta4HfC5 composite ceramics were prepared by a combination of two-step mechanical alloying and reactive hot-pressing sintering. The microstructural evolution and mechanical properties of the resulting SiBCN-Ta4HfC5 were studied. After the first-step milling of 30 h, the raw materials of TaC and HfC underwent crushing, cold sintering, and short-range interdiffusion

Thermoelectric (TE) performance of Ca3Co4O9 (CCO) has been investigated extensively via a doping strategy in the past decades. However, the doping sites of different sublayers in CCO and their contributions to the TE performance remain unrevealed because of its strong correlated electronic system. In this work, Sr and Ti are chosen to realize doping at the [Ca2CoO3] and [CoO2] sublayers in CCO. It

Polymer-ceramic composites are widely applied in microwave substrate materials due to the excellent dielectric properties and simple preparation process recently. Polytetrafluoroethylene-based (PTFE) composites filled with Zn0.5Ti0.5NbO4 (ZTN) ceramic particles were fabricated by hot-pressing. The particles were modified by C14H19F13O3Si to enhance the interface compatibility between PTFE and ZTN powders

A melilite Ba2CuGe2O7 ceramic was characterized by low sintering temperature and moderate microwave dielectric properties. Sintered at 960 °C, the Ba2CuGe2O7 ceramic had a high relative density 97%, a low relative permittivity (εr) 9.43, a quality factor (Q×f) of 20,000 GHz, and a temperature coefficient of resonance frequency (τf) −76 ppm/°C. To get a deep understanding of the relationship between

In this work, three-dimensional (3D) Cf/SiBCN composites were fabricated by polymer infiltration and pyrolysis (PIP) with poly(methylvinyl)borosilazane as SiBCN precursor. The 3D microstructure evolution process of the composites was investigated by an advanced X-ray computed tomography (XCT). The effect of dicumyl peroxide (DCP) initiator addition on the crosslinking process, microstructure evolution

The effect of etching environment (opened or closed) on the synthesis and electrochemical properties of V2C MXene was studied. V2C MXene samples were synthesized by selectively etching of V2AlC at 90 °C in two different environments: opened environment (OE) in oil bath pans under atmosphere pressure and closed environment (CE) in hydrothermal reaction kettles under higher pressures. In OE, only NaF

In this study, Ti3(Al,Ga)C2/Al2O3 composites were successfully synthesized by in situ hot pressing at 1350 °C for 2 h using Ti, Al, TiC, and Ga2O3 as raw materials. X-ray diffraction and scanning electron microscopy were used for characterizing the phase identities and microstructures of the sintered composites. The dependence of the Vickers hardness and flexural strength on the Al2O3 content was found

In this study, deep-red emitting Mg2TiO4:Mn4+ phosphor ceramics were synthesized by the high temperature solid-state reaction method. The ceramics can be excited by the 465 nm blue light and had a narrow emission with a full width at half maximum (FWMH) value of 31 nm. The peak wavelength was located at 658 nm, which matched the demanded wavelength for photosynthesis. The crystal field strength (Dq)

Short-carbon-fibers (Csf) reinforced Ti3SiC2 matrix composites (Csf/Ti3SiC2, the Csf content was 0 vol%, 2 vol%, 5 vol%, and 10 vol%) were fabricated by spark plasma sintering (SPS) using Ti3SiC2 powders and Csf as starting materials at 1300 °C. The effects of Csf addition on the phase compositions, microstructures, and mechanical properties (including hardness, flexural strength (σf), and KIC) of

The Yb:Lu2O3 precursor made up of spherical particles was synthesized through the co-precipitation method in the water/ethanol solvent. The 5 at% Yb:Lu2O3 powder is in the cubic phase after calcination at 1100 °C for 4 h. The powder also consists of spherical nanoparticles with the average particle and grain sizes of 96 and 49 nm, respectively. The average grain size of the pre-sintered ceramic sample

Rare earth (RE = La3+, Sm3+, Pr3+) ion doped Pb(Mg1/3Nb2/3)O3-PbTiO3 (RE-PMN-PT) ferroelectric thin films with compositions near the morphotropic phase boundary were grown on the Pt/TiO2/SiO2/Si(100) substrate using sol-gel/spin coating method. The phase structure, electrical properties, and photoluminescence performance of thin films were investigated systematically. The highly (100)-preferred orientation

Considering the emergence of severe electromagnetic interference problems, it is vital to develop electromagnetic (EM) wave absorbing materials with high dielectric, magnetic loss and optimized impedance matching. However, realizing the synergistic dielectric and magnetic losses in a single phase material is still a challenge. Herein, high entropy (HE) rare earth hexaborides (REB6) powders with coupling

High-entropy boride-silicon carbide (HEB-SiC) ceramics were fabricated using boride-based powders prepared from borothermal and boro/carbothermal reduction methods. The effects of processing routes (borothermal reduction and boro/carbothermal reduction) on the HEB powders were examined. HEB-SiC ceramics with > 98% theoretical density were prepared by spark plasma sintering at 2000 °C. It was demonstrated

Porous mullite hollow fiber membranes were prepared with a combined phase-inversion and sintering method, using three sintering additives including yttrium stabilized zirconia (YSZ), small mullite particles (SMP), and titanium oxide (TiO2) to promote the particle sintering. The results indicated that all the three additives could improve the sintering performance of mullite hollow fiber membranes due

Calcium stabilized nitrogen rich sialon ceramics having a general formula of CaxSi12-2xAl2xN16 with x value (x is the solubility of cation Ca in α-sialon structure) in the range of 0.2–2.2 for compositions lying along the Si3N4:1/2Ca3N2:3AlN line were synthesized using nano/submicron size starting powder precursors and spark plasma sintering (SPS) technique. The development of calcium stabilized nitrogen

The critical requirements for the environmental barrier coating (EBC) materials of silicon-based ceramic matrix composites (CMCs) include good tolerance to harsh environments, thermal expansion matches with the interlayer mullite, good high-temperature phase stability, and low thermal conductivity. Cuspidine-structured rare-earth aluminates RE4Al2O9 have been considered as candidates of EBCs for their

In order to enhance dielectric properties of polymer-derived SiC ceramics, a novel single-source-precursor was synthesized by the reaction of an allylhydrido polycarbosilane (AHPCS) and divinyl benzene (DVB) to form carbon-rich SiC. As expected, the free carbon contents of resultant SiC ceramics annealed at 1600 °C are significantly enhanced from 6.62 wt% to 44.67 wt%. After annealing at 900–1600 °C

Multiferroic BiFeO3-based ceramics were synthesized using the rapid liquid-phase sintering method. The rare-earth ion (Sm3+, Gd3+, Y3+) doping causes structural distortion without changing the intrinsic rhombohedral perovskite structure. Raman analysis shows that the effect of doping on E modes is greater than A1 modes, and the microstructure of FeO6 octahedron can be regulated by ion doping. A-site

Y2O3:Yb3+ 5 at% ceramics have been synthesized by the reactive sintering method using different commercial yttria powders (Alfa-Micro, Alfa-Nano, and ITO-V) as raw materials. It has been shown that all Y2O3 starting powders consist from agglomerates up to 5–7 µm in size which are formed from 25–60 nm primary particles. High-energy ball milling allows to significantly decreasing the median particle

Hetero-element doped lithium orthosilicates have been considered as advanced tritium breeders due to the superior performances. In this work, Li4Si1−xTixO4 ceramics were prepared by proprietary hydrothermal process and multistage reactive sintering. The reaction mechanism of Li4Si1−xTixO4 was put forward. XRD and SEM analyses indicate that insertion of Ti leads to lattice expansion, which promotes

Nano-magnetic ferrites with composition Mg1−xZnxFe2O4 (x = 0.3, 0.4, 0.5, 0.6, and 0.7) have been prepared by coprecipitation method. X-ray diffraction (XRD) studies showed that the lattice parameter was found to increase from 8.402 to 8.424 Å with Zn2+ ion content from 0.3 to 0.7. Fourier transform infrared (FTIR) spectra revealed two prominent peaks corresponding to tetrahedral and octahedral at

The non-stoichiometric Li3Mg2Sb1−xO6 (0.05 ⩽ x ⩽ 0.125) compounds have been prepared via the mixed oxide method. The influences of Sb nonstoichiometry on the sintering behavior, microstructure, phase composition along with microwave dielectric performances for Li3Mg2Sb1−xO6 ceramics were studied. Combined with X-ray diffraction (XRD) and Raman spectra, it was confirmed that phase composition could

The binary skutterudite CoSb3 is a narrow bandgap semiconductor thermoelectric (TE) material with a relatively flat band structure and excellent electrical performance. However, thermal conductivity is very high because of the covalent bond between Co and Sb, resulting in a very low ZT value. Therefore, researchers have been trying to reduce its thermal conductivity by the different optimization methods

TaB2-SiC coating modified by different content of MoSi2 was fabricated on graphite substrate with SiC inner coating by liquid phase sintering to elevate the anti-oxidation capability of the TaB2-SiC coatings. As compared to the sample with the TaB2—40wt%SiC coating, the coating sample modified with MoSi2 exhibited a weight gain trend at lower temperatures, the fastest weight loss rate went down by

Inspired by the micro-nano structure on the surface of biological materials or living organisms, micro-nano structure has been widely investigated in the field of functional coatings. Due to its large specific surface area, porosity, and dual-scale structure, it has recently attracted special attention. The typical fabrication processes of micro-nano structured coatings include sol-gel, hydrothermal

The dense ZnO-Bi2O3-MnO2-xSiO2 (ZBMS) varistors for x = 0, 1, 2, 3 wt% were fabricated by flash sintering method under the low temperature of 850 °C within 2 min. The sample temperature was estimated by a black body radiation model in the flash sintering process. The crystalline phase assemblage, density, microstructure, and electrical characteristics of the flash-sintered ZBMS varistors with different

In this study, low-temperature fired CaMg1−xLi2xSi2O6 microwave dielectric ceramics were prepared via the traditional solid-state reaction method. In this process, 0.4 wt% Li2CO3-B2O3-SiO2-CaCO3-Al2O3 (LBSCA) glass was added as a sintering aid. The results showed that ceramics consisted of CaMgSi2O6 as the main phase. The second phases were CaSiO3 always existing and Li2SiO3 occurring at substitution

Guided by the theoretical prediction, a new MAX phase V2SnC was synthesized experimentally for the first time by reaction of V, Sn, and C mixtures at 1000 °C. The chemical composition and crystal structure of this new compound were identified by the cross-check combination of first-principles calculations, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and high resolution scanning

The effects of Mn doping on the microstructure and magnetic properties of CuFeO2 systems were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy, scanning electron microscopy (SEM), and a physical property measurement method. The microstructure measurements demonstrated that the substitution of Mn for Fe can cause lattice distortion, promote grain growth, and change the valence

Er3+-doped Ba0.85Ca0.15Ti0.9Zr0.1O3 (xEr-BCTZ, x = 0, 0.005, 0.01, 0.015) multifunctional thick films were prepared by the tape-casting method, using sol-gel-derived nano-sized powders as the matrix material. The surface morphologies, photoluminescence, and electrical properties were investigated. Dense microstructures with pure perovskite structure were obtained in the thick films. By doping an appropriate

Residual stress originated from thermal expansion mismatch determines the mechanical properties of ceramic matrix composites (CMCs). Here, continuous SiC fiber reinforced SiC matrix (SiCf/SiC) composites were fabricated by nano-infiltration and transient eutectic-phase (NITE) method, and the residual stress of the composites was investigated using high-temperature Raman spectrometer. With temperature

Cu1.8S has been considered as a potential thermoelectric (TE) material for its stable electrical and thermal properties, environmental benignity, and low cost. Herein, the TE properties of nanostructured Cu1.8S1−xTex (0 ⩽ x ⩽ 0.2) bulks fabricated by a facile process combining mechanical alloying (MA) and room-temperature high-pressure sintering (RT-HPS) technique were optimized via eliminating the

Mn2+ and the trivalent europium (Eu3+)-doped MgGa2O4 ceramics are characterized using a multi-experimental approach. The formation of spinel-structured ceramics is ascertained from X-ray diffraction (XRD) analysis. Morphology investigations with transmission electron microscopy (TEM) show irregularly shaped grains and grain boundaries with a homogeneous distribution of Eu3+ ions. The inability of Eu

High strength SiC whisker-reinforced Ti3SiC2 composites (SiCw/Ti3SiC2) with an improved thermal conductivity and mechanical properties were fabricated by spark plasma sintering. The bending strength of 10 wt% SiCw/Ti3SiC2 was 635 MPa, which was approximately 50% higher than that of the monolithic Ti3SiC2 (428 MPa). The Vickers hardness and thermal conductivity (k) also increased by 36% and 25%, respectively

A series of Sm2Zr2O7-SiC composites doped with different volume fraction and particle size of SiC were prepared by hot pressing at 1300 °C. The phase of the composites prepared is P-Sm2Zr2O7 and C-SiC, and no other diffraction peaks exist, which indicates that Sm2Zr2O7 has great chemical compatibility with SiC. The thermal conductivity and phonon thermal conductivity of the Sm2Zr2O7-SiC composites

Bismuth ferrite (BiFeO3)-based materials are multiferroic materials widely studied. This study reports that strong ferroelectricity and enhanced magnetic performance are simultaneously obtained in the quenched (1−x)BiFeO3−xBaTiO3 (BFBT100x, x = 0.2 and 0.3) ceramics. Quenching treatment can reduce the amount of defects and Fe2+ ions and make the defect dipole in a random state, which is conducive to

A rapid and facile approach was developed for the synthesis of ultrafine SmAlO3 powders through the combustion of stearic acid precursors. The obtained products were characterized by typical techniques including X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), and transmission electron microscopy

ZrB2-SiBCN ceramics with ZrO2 additive are hot-pressed under a constant applied pressure. The densification behavior of the composites is studied in a view of creep deformation by means of the Bernard-Granger and Guizard model. With determination of the stress exponent (n) and the apparent activation energy (Qd), the specific deformation mechanisms controlling densification are supposed. Within lower

As an optical material, Y2O3 transparent ceramics are desirable for application as laser host materials. However, it is difficult to sinter and dense of Y2O3 hinders the preparation of high-quality optical ceramics via traditional processes. In this work, we use La2O3 as a sintering aid for fabricating high-transparency Y2O3 ceramics using a vacuum sintering process. It is demonstrated that the in-line

Three dimensional (3D) printing technology by direct ink writing (DIW) is an innovative complex shaping technology, possessing advantages of flexibility in fabrication, high efficiency, low cost, and environmental-friendliness. Herein, 3D printing of complex alumina ceramic parts via DIW using thermally induced solidification with carrageenan swelling was investigated. The rheological properties of

Graphene with excellent comprehensive properties has been considered as a promising filler to reinforce ceramics. While numerous studies have been devoted to the improvement of mechanical and electrical properties, incorporating graphene to ceramics also offers new opportunities for endowing ceramics with versatility. In this review, the recent development of graphene/ceramic bulk composites is summarized

Multilayer ceramic capacitors (MLCCs) for energy storage applications require a large discharge energy density and high discharge/charge efficiency under high electric fields. Here, 0.87BaTiO3-0.13Bi(Zn2/3(Nb0.85Ta0.15)1/3)O3 (BTBZNT) MLCCs with double active dielectric layers were fabricated, and the effects of inner electrode and sintering method on the energy storage properties of BTBZNT MLCCs were

The thermal stability and fatigue resistance of piezoelectric ceramics are of great importance for industrialized application. In this study, the electrical properties of (0.99-x)(K0.48Na0.52)(Nb0.975Sb0.025)O3-0.01CaZrO3-x(Bi0.5Na0.5)HfO3 ceramics are investigated. When x = 0.03, the ceramics exhibit the optimal electrical properties at room temperature and high Curie temperature (TC = 253 °C). In

Pressure measurement with excellent stability and long time durability is highly desired, especially at high temperature and harsh environments. A polymer-derived silicoboron carbonitride (SiBCN) ceramic pressure sensor with excellent stability, accuracy, and repeatability is designed based on the giant piezoresistivity of SiBCN ceramics. The SiBCN ceramic sensor was packaged in a stainless steel case

A novel single-source-precursor for SiC-TaC-C nanocomposites was successfully synthesized by the chemical reaction between a polycarbosilane (allylhydridopolycarbosilane, AHPCS) and tantalum(V) chloride (TaCl5), which was confirmed by Fourier transform infrared spectra (FTIR) measurement. After pyrolysis of the resultant single-source-precursors at 900 °C, amorphous ceramic powders were obtained. The

Rare-earth tantalates and niobates (RE3TaO7 and RE3NbO7) have been considered as promising candidate thermal barrier coating (TBC) materials in next generation gas-turbine engines due to their ultra-low thermal conductivity and better thermal stability than yttria-stabilized zirconia (YSZ). However, the low Vickers hardness and toughness are the main shortcomings of RE3TaO7 and RE3NbO7 that limit their

Hydroxyapatite (HA) bioceramic scaffolds were fabricated by using digital light processing (DLP) based additive manufacturing. Key issues on the HA bioceramic scaffolds, including dispersion, DLP fabrication, sintering, mechanical properties, and biocompatibility were discussed in detail. Firstly, the effects of dispersant dosage, solid loading, and sintering temperature were studied. The optimal dispersant

Carbon fiber reinforced silicon carbide-hafnium carbide (C/SiC-HfC) composite was prepared by precursor infiltration and pyrolysis process. Then, ablation behavior of C/SiC-HfC was evaluated in plasma wind tunnel. It was found that oxide layer formed during ablation significantly influenced the surface temperature. Formation of dense HfO2-SiO2 layer under low heat flux led to stable surface temperature

In this paper, both the 1D radial mode and the equivalent circuit of a piezoceramic disk resonator were theoretically analyzed based on IEEE standards. And then, the radial resonance frequency spectra of the PZT-based (Nb/Ce co-doped Pb(Zr0.52Ti0.48)O3, abbreviated as PZT-NC) piezoceramic circular disks were measured by an impedance analyzer. A set of resonance frequency spectra including six electrical

Pure K0.5Na0.5NbO3 (KNN) and KNN doped with Li+ (6% mole), La3+(1.66%, 5%, 6% mole), and Ti4+ (10% mole) were prepared by mixture of oxides using high-energy milling and conventional solid-state reaction. The effects of the dopant on the physical properties of pure KNN have been evaluated based on the structural, ferroelectric, pyroelectric, and dielectric measurements. The XRD measurements show that

High-entropy nanomaterials have been arousing considerable interest in recent years due to their huge composition space, unique microstructure, and adjustable properties. Previous studies focused mainly on high-entropy nanoparticles, while other high-entropy nanomaterials were rarely reported. Herein, we reported a new class of high-entropy nanomaterials, namely (Ta0.2Nb0.2Ti0.2W0.2Mo0.2)B2 high-entropy

High-entropy ceramics attract more and more attention in recent years. However, mechanical properties especially strength and fracture toughness for high-entropy ceramics and their composites have not been comprehensively reported. In this work, high-entropy (Ti0.2Zr0.2Hf0.2Nb0.2Ta 0.2)B2 (HEB) monolithic and its composite containing 20 vol% SiC (HEB–20SiC) are prepared by hot pressing. The addition

N-type Se&Lu-codoped Bi2Te3 nanopowders were prepared by hydrothermal method and sintered by spark plasma sintering technology to form dense samples. By further doping Se element into Lu-doped Bi2Te3 samples, the thickness of the nanosheets has the tendency to become thinner. The electrical conductivity of Lu0.1Bi1.9Te3−xSex material is reduced with the increasing Se content due to the reduced carrier

In this study, the upconversion (UC) emissions of Er3+ and Yb3+ co-doped SrZrO3 nanocrystals (NCs) were investigated in terms of the thermal annealing temperature and concentration of Er3+ ions and compared with the emissions under a near-ultraviolet (near-UV) excitation. The NCs were synthesized by the combustion method, and the as-synthesized NCs were post-annealed at high temperatures. The X-ray

This article reports the first example of 3D printed continuous SiO2 fiber reinforced wave-transparent ceramic composites via an adaptation of direct ink writing technology to improve the mechanical and dielectric properties of ceramics. The ceramic inks showed good printability by adding nano-SiO2 powder. The effective continuous fiber-reinforced printing progress was achieved through the design and

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Polarization switching in lead-free (K0.40Na0.60)NbO3 (KNN) single crystals was studied by switching spectroscopy piezoresponse force microscopy (SS-PFM). Acquisition of multiple hysteresis loops on a closely spaced square grid enables polarization switching parameters to be mapped in real space. Piezoresponse amplitude and phase hysteresis loops show collective symmetric/asymmetric characteristics