Nd1-xSrxMnO3 (x = 0.3): A perovskite manganite ceramic that exhibits PTC and NTC double properties

Nd_1-xSr_xMnO₃ (NSMO, x = 0.280, 0.300, 0.330, 0.350, and 0.375) polycrystalline ceramics were fabricated using the sol-gel method. The crystal structure, surface morphology, valence state, elements distribution, and electrical properties were examined to understand the effect of Sr doping on NdMnO₃ ceramics. The resistivity of the NSMO ceramics was measured using a standard four-probe method. The results obtained revealed that Sr doping significantly decreased the resistivity of the ceramics, which can be explained by the double exchange (DE) interaction and small-polaron hopping (SPH) model. The Nd_0.70Sr_0.30MnO₃ ceramic had a positive temperature coefficient (PTC) of resistivity (16.69% K^?1) at 197.5 K, and is expected to be used for preparing electronic switches with high sensitivity. Additionally, the NSMO ceramics maintained a stable negative temperature coefficient (NTC) of resistivity (?1% K^?1) for x = 0.300 in the temperature range of 210.6–342.5 K. In conclusion, it is worth exploring materials with a high PTC and NTC over an extended temperature range, possessing the double potential function for high sensitivity or wide-temperature detection for electronic switches or infrared bolometers.     

Dielectric Properties and Low‐Temperature Sintering of the Ba0.6Sr0.4TiO3 Ceramics with B2O3/CuO Additions

The sintering behaviors and dielectric properties of Ba_0.6Sr_0.4TiO₃ ceramics were investigated as a function of B₂O₃ and CuO content. The addition of both B₂O₃ and CuO reduced the sintering temperature of Ba_0.6Sr_0.4TiO₃ about 500°C. It was suggested that a liquid phase BaCu(B₂O₅) was formed and assisted the densification of Ba_0.6Sr_0.4TiO₃ ceramics. Ba_0.6Sr_0.4TiO₃ ceramics co‐doped with 3.0 mol% B₂O₃, and 2.0 mol% CuO, sintered at 950°C for 5 h, had a dense microstructure and showed good microwave dielectric properties of a moderate dielectric constant (ε = 1048), low dielectric loss (0.0090) and high tunability (42.2%) at dc electric field of 30 kV/cm.     

Dielectric properties of [(Pb1 - xSrx)O.TiO2)]-[2SiO2.B2O3]-[K2O] glass ceramics

Abstract

Dielectric properties of glass ceramics prepared in the [(Pb_{1 - x}Sr_x)O.TiO₂)]- [2SiO₂.B₂O₃]-[K₂O] system have been studied. The Curie temperature of crystalline phases has been found to decrease with decreasing Pb²⁺/Sr²⁺ ratio in the initial glass. This adds support to the authors' previous findings from XRD peak intensity studies suggesting that the crystallites are in solid solution in the system (Pb_{1 - x}Sr_x)TiO₃.     

Influence of 4ZnO–B2O3 Addition on Dielectric Properties and Microstructures of Barium Strontium Titanate

This study investigates the effect of 4ZnO–B₂O₃ on the sintering behavior, dielectric properties, and microstructures of Ba_0.6Sr_0.4TiO₃ (BST) ceramics. These ceramics were sintered in air at temperatures ranging from 900°C to 1080°C. BST ceramics with 4ZnO–B₂O₃ addition can be sintered to a theoretical density higher than 95% at 1050°C. A secondary phase (Ba₂ZnTi₅O₁₃) is produced in the BST ceramics during 4ZnO–B₂O₃ addition. Compositional analysis using TEM-EDX of the BST ceramics with 3 wt% 4ZnO–B₂O₃ revealed that the Zn ion is generally located at the triple points. This result indicates that BaO, TiO₂, and ZnO form a liquid phase that acts as a secondary phase at the lower sintering temperatures. The amount of secondary phase was observed to increase as the amount of 4ZnO–B₂O₃ additives increased. In addition, the original Ba_0.6Sr_0.4TiO₃ phase was shifted to the Ba_0.5Sr_0.5TiO₃ phase by the addition of 3 wt% 4ZnO–B₂O₃ at 1050°C. The Ba_0.6Sr_0.4TiO₃ ceramic with 2 wt% 4ZnO–B₂O₃ sintered at 1050°C in air for 2 h exhibited dielectric properties of ɛ_r=1883 and dissipation loss=0.36%. Moreover, BST with 1 wt% 4ZnO–B₂O₃ addition sintered at 1080°C exhibits dielectric properties of ɛ_r=2330, dissipation loss=0.29%, and bulk density >95% of theoretical density.     

Effect of La doping on tunable behavior of sol–gel-derived PST thin film

Pb_xSr_1−xTiO₃ and (Pb_0.4Sr_0.6)_1−xLa_2x/3TiO₃ thin films were prepared on ITO/glass substrate by sol–gel technique. The crystalline phase structures of thin films were investigated by XRD. The dielectric properties were measured by LCZ meter. Results show that the perovskite phase was stable in Pb_xSr_1−xTiO₃ thin film. Its lattice constant was found to increase with the increase of x. When Pb/Sr ratio was about 50/50, the transformation of the perovskite phase between cubic and tetragonal took place at room temperature. To ensure better tunability, Pb_0.4Sr_0.6TiO₃ thin film was selected in both paraelectric state (cubic structure) and near the phase transformation point between cubic and tetragonal. The tunability of more than 80% and figure of merit (FOM) of 14.17 were obtained. (Pb_0.4Sr_0.6)_1−xLa_2x/3TiO₃ was also prepared as La-doped thin film. Its dielectric constant was decreased below x = 0.4 and then increased above x = 0.4 with the increase in x. The inharmonic coefficient depicting ability of tunability of (Pb_0.4Sr_0.6)_1−xLa_2x/3TiO₃ thin film kept constant due to the changeable shape of the crystal cell under electric field at a fixed temperature below x = 0.4, which is in good agreement with Johnson's theory. And the coefficient reveals a distinctive variable because of easily changeable shape under different bias above x = 0.4. The tunability of about 70% and FOM of about 7 were obtained in the (Pb_0.4Sr_0.6)_1−xLa_2x/3TiO₃ thin film.     

Microstructures and dielectric properties of spark plasma sintered Ba0.4Sr0.6TiO3/CaCu3Ti4O12 composite ceramics

(1 − x)Ba_0.4Sr_0.6TiO₃/xCaCu₃Ti₄O₁₂ composite ceramics were prepared by spark plasma sintering. Sintering behavior, microstructures and dielectric properties of the composite ceramics were investigated by XRD, SEM, EDS and dielectric spectrometer. Dense composite ceramics consisting of Ba_0.4Sr_0.6TiO₃ phase and CaCu₃Ti₄O₁₂ phase were prepared at 800 °C for 0 min. The dielectric loss of the composite ceramic decreased with increasing amount of Ba_0.4Sr_0.6TiO₃, and the high dielectric constant were retained. Moreover, the better temperature stability of dielectric constant was obtained. These improvements of dielectric characteristics have great scientific significance for potential application.     

Dielectric relaxation behavior and energy storage properties in Ba0.4Sr0.6Zr0.15Ti0.85O3 ceramics with glass additives

Ba_0.4Sr_0.6Zr_0.15Ti_0.85O₃ ceramics with SrO–B₂O₃–SiO₂ glass additives were prepared via the solid state reaction route. The effects of glass contents on the sintering behavior, dielectric properties, microstructures, and energy storage properties of BSZT ceramics were investigated. Dielectric breakdown strength of 22.4 kV/mm was achieved for BSZT ceramics with 20 wt% glass addition. Dielectric relaxation behavior was observed in dielectric loss versus temperature plots. In order to investigate the mechanism of dielectric breakdown performance, the relationship between dielectric breakdown strength and grain boundary barrier was studied by the measurements of breakdown strength and activation energy. A discharged energy density of 0.45 J/cm³ with an energy efficiency of 88.2% was achieved for BSZT ceramics with 5 wt% glass addition.     

Screening sintering aids for 0.88(Bi0.4Na0.2K0.2Ba0.2)TiO3–0.12Sr(Mg1/3Nb2/3)O3 high-entropy dielectric ceramics

The liquid phase screening method was used to search for sintering aids for 0.88(Bi_0.4K_0.2Na_0.2Ba_0.2)TiO₃–0.12Sr(Mg_1/3Nb_2/3)O₃ ceramics. The efficiency of the method was tested by studying the effect of three selected oxides on the densification and properties of the ceramics. The results showed that all three selected sintering aids can improve the sintering ability and energy storage performance. The sample with 1.5 mol% SiO₂ exhibited a recoverable energy storage density and storage efficiency of 2.61 J/cm³ and 77.4% at an electric field of 270 kV/cm, indicating its promising applications in the low-to-moderate fields.     

Preparation and characterization of a green emitting Li2Ca0.4Sr0.6SiO4:Tb3+ phosphor with afterglow behavior

A novel green emitting long afterglow phosphor Li₂Ca_0.4Sr_0.6SiO₄:Tb³⁺ was obtained via a high temperature solid-state reaction in air atmosphere. X-ray diffraction (XRD), photoluminescence spectroscope (PLS), long afterglow spectroscope (LAS) and thermal luminescence spectroscope (TLS) were performed to characterize the physical properties of the phosphors. Typical ⁵D₄-⁷F_j transitions of Tb³⁺ ions were detected by PL spectra, corresponding to CIE chromaticity coordinates of x =0.3456, y =0.5745. An optimal concentration of Tb³⁺ in the substrate was determined as 0.8 at%. The Li₂Ca_0.4Sr_0.6SiO₄ phosphors showed a typical afterglow behavior when the UV source was switched off. A typical triple exponential decay behavior was confirmed after fitting the experimental data. Thermal simulated luminescence study further indicated that the afterglow behavior of Li₂Ca_0.4Sr_0.6SiO₄:Tb³⁺ phosphors was generated by the recombination of electrons with the holes resulted from the doping of rare-earth ions (Tb³⁺) in Li₂Ca_0.4Sr_0.6SiO₄ host. The long afterglow luminescence mechanism of Li₂Ca_0.4Sr_0.6SiO₄:Tb³⁺ is illustrated and discussed in detail on the basis of experimental results.     

The Influence of La Doping and Heterogeneity on the Thermoelectric Properties of Sr3Ti2O7 Ceramics

La‐doping mechanisms and thermoelectric properties of Sr₃Ti₂O₇ Ruddlesden–Popper (RP) ceramics sintered under air and flowing 5% H₂ at 1773 K for 6 h have been investigated. Changes in lattice parameters and conductivity revealed a limited interstitial anion mechanism (~1 at.%) based on La³⁺ + ½O^2?→Sr²⁺, which resulted in insulating samples when processed in air. In contrast, electronic donor‐doping (La³⁺ + e^? → Sr²⁺) and oxygen loss [O^2? → ½ O₂ (g) + 2 e^?] are the dominant mechanism(s) in 5% H₂‐sintered ceramics with a solution limit of ~5 at.%. The increased solubility limit is attributed to the formation of Ti³⁺ during reduction, which compensates for the extra positive charge associated with La on the A‐site and also to the occurrence of oxygen loss due to the reducing conditions. For 5% H₂‐sintered samples, an insulating surface layer was formed associated with SrO volatilization and oxygen uptake (during cooling) from the sintering. Unless removed, the insulating layer masked the conductive nature of the ceramics. In the bulk, significantly higher power factors were obtained for ceramics that were phase mixtures containing highly conductive perovskite‐based (Sr,La)TiO_3?δ (ST). This highlights the superior power factor properties of reduced perovskite‐type ST phases compared to reduced RP‐type Sr₃Ti₂O₇ and serves as a precaution for the need to identify low levels of highly conducting perovskite phases when exploring rare‐earth doping mechanisms in RP‐type phases.     

Colossal dielectric permittivity in (Al+Nb) co-doped Ba0.4Sr0.6TiO3 ceramics

Stimulated by the outstanding colossal permittivity behavior achieved in trivalent and pentavalent cations co-doped rutile TiO₂ ceramics, the co-doping effects on the dielectric behavior of Ba_0.4Sr_0.6TiO₃ ceramics were further explored. In this work, (Al + Nb) co-doped Ba_0.4Sr_0.6TiO₃ ceramics were synthesized via a standard solid state ceramic route. The structural evolution was analyzed using X-ray diffraction patterns and Raman spectra. Dense microstructures with no apparent change of grain morphology were observed from the scanning electron microscopy. A huge enhancement of dielectric permittivity was obtained with 1 mol% (Al + Nb) doping and excellent dielectric performances (ε_r ∼ 20,000, tanδ ∼ 0.06 at 1 kHz) were achieved after further heat treatment. The formation of electron pinned defect dipoles localized in grains may account for the optimization of dielectric behaviors and the corresponding chemical valence states were confirmed from the XPS results.     

ZnBO-doped (Ba, Sr)TiO3 ceramics for the low-temperature sintering process

ZnBO-doped (Ba, Sr)TiO₃ ceramics were investigated for low-temperature co-fired ceramics (LTCCs) applications. Until now, B₂O₃ and Li₂CO₃ dopants have been commonly employed as the low-temperature sintering aids. In this paper, we suggest ZnBO as an alternative dopant to the B₂O₃ and Li₂CO₃. To reduce the sintering temperature of (Ba, Sr)TiO₃, we have added 1–5 wt.% of ZnBO to (Ba, Sr)TiO₃. ZnBO-doped (Ba, Sr)TiO₃ ceramics were respectively sintered from 750 to 1350 °C by 50 °C to confirm the sintering temperature with different dopant contents. By adding 5 wt.% of ZnBO to the (Ba, Sr)TiO₃ ceramics, the sintering temperature of (Ba, Sr)TiO₃ ceramics can be reduced to 1100 °C. From the XRD analysis, ZnBO-doped (Ba, Sr)TiO₃ has no pyro phase. By adding ZnBO dopants to (Ba, Sr)TiO₃ ceramics, both of relative dielectric permittivity and loss tangent were decreased. From the frequency dispersion of dielectric properties, the relative dielectric permittivity and loss tangent of 5 wt.% ZnBO-doped (Ba, Sr)TiO₃ were 1180 and 3.3 × 10⁻³, while those of BST were 1585 and 4.8 × 10⁻³, respectively.     

Effects of raw materials on nonhydrolytic sol-gel synthesis of Ba0.6Sr0.4TiO3

The effects of raw materials on the nonhydrolytic sol-gel synthesis of Ba_0.6Sr_0.4TiO₃ were systematically studied in this work. The samples were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM). Ba(CH₃COO)₂, Sr(CH₃COO)₂, BaCO₃ and SrCO₃ can undergo deesterification substitution reaction with Ti(OC₄H₉)₄ to synthesize Ba_0.6Sr_0.4TiO₃ phase. Sample taking Ba(CH₃COO)₂ and Sr(CH₃COO)₂ as barium and strontium source has better Ba_0.6Sr_0.4TiO₃ synthesis results than that of samples using BaCO₃ or SrCO₃. Ba_0.6Sr_0.4TiO₃ phase can not be synthesized at low temperature taking BaCl₂, SrCl₂ and TiOSO₄ as barium, strontium or titanium source due to their strong ionic bonding. TiCl₄ undergoes an alcoholysis reaction with (oxygen donor) alcohol to form a multimolecular association structure and solvated complex chlorotitanium alkoxide, which reduces the possibility of a deesterification polycondensation reaction. The Ba_0.6Sr_0.4TiO₃ phase cannot be synthesized at low temperatures when CH₃CH₂OH or C₃H₇OH is used as the solvent. The synthesis of Ba_0.6Sr_0.4TiO₃ is insufficient because of the coordination ability and solvation effect when CH₃COOH is used as the solvent. The synthesis of Ba_0.6Sr_0.4TiO₃ is the best when Ba(CH₃COO)₂, Sr(CH₃COO)₂, Ti(OC₄H₉)₄ and glycerol (C₃H₈O₃) are used as the barium source, strontium source, titanium source and solvent, respectively. Pure Ba_0.6Sr_0.4TiO₃ phase with a particle size of 17–43 nm and high dispersion is synthesized when the molar ratio of barium-strontium-titanium is 0.6:0.4:1.2.     

A-site compositional modulation in barium titanate based relaxor ceramics to achieve simultaneously high energy density and efficiency

Dielectric ceramics capacitors (DCC) with excellent energy storage performance (ESP) and charge-discharge performance (CDP) is very critical in the field of advanced electronics and power systems. A strategy that improves the ESP of 0.6Ba(Zr_0.2Ti_0.8)O₃-0.4(Na_0.5Bi_0.5)TiO₃ (BZT-NBT) ceramics was proposed via Sr²⁺ doping. XRD and SEM results confirmed that 0.6(Ba_1-xSr_x)(Zr_0.2Ti_0.8)O₃-0.4(Na_0.5Bi_0.5)TiO₃ (x = 0, 0.1, 0.2, 0.3, 0.4) (BSZT-NBT) ceramics formed dense and stable perovskite solid solutions. The relaxor ferroelectric (RFE) properties of BSZT-NBT ceramics were also well proved by dielectric behaviors. A large recoverable energy storage density (W_rec) and large efficiency (η) of 3.72 J cm⁻³ and 94.03 % (x = 0.3) can be simultaneously obtained at 289 kV cm^-1. ESP of BSZT-NBT (x = 0.3) ceramics at 180 kV cm^-1 exhibit good frequency (1−100 Hz) and temperature (room temperature (RT)-120 °C) stability. BSZT-NBT (x = 0.3) ceramics at 120 kV cm⁻¹ exhibit a prominent power density (P_D) and rapid discharge rate (t_0.9) of of 37.62 MW cm⁻³ and 70.6 ns. All evidences confirm that introduction of Sr²⁺ into A-site of barium titanate-based ceramics could effectively improve ESP.     

Anomalous Correlation between Dielectric Constant and Tunability in (Ba,Sr)TiO3–MgO–Mg2SiO4 Composite Ceramics

(Ba, Sr)TiO₃–MgO–Mg₂SiO₄ composite ceramics were prepared by a solid‐state reaction method. The microstructures, microwave dielectric characteristics, and tunability of composite ceramics were investigated. An anomalous correlation between tunability and dielectric constant was observed: with the increase in Mg₂SiO₄ content and the decrease in MgO content, the dielectric constant of (Ba, Sr)TiO₃–MgO–Mg₂SiO₄ composite ceramics decreases, but the tunability increases. The anomalous increased tunability is beneficial for tunable microwave applications and can be attributed to the redistribution of the electric field. For 50Ba_0.5Sr_0.5TiO₃–(50?x)MgO–xMg₂SiO₄, the dielectric constant was decreased from 164.2 to 126.5 by increasing Mg₂SiO₄ content from 5 to 45 wt% and the tunability at 3.9 kV/mm increased from 11.5% to 15.2%.     

Effect of SiO2 additive on dielectric response and energy storage performance of Ba0.4Sr0.6TiO3 ceramics

SiO₂-added barium strontium titanate ceramics Ba_0.4Sr_0.6TiO₃-xwt%SiO₂ (x=0, 0.5, 1, 3, BSTSx) were prepared via a traditional solid state reaction method. The effect of SiO₂ additive on the microstructure, dielectric response and energy storage properties was investigated. The results confirmed that with the increase of SiO₂ additive, diffuse phase transition arises and the dielectric constant decreases. An equivalent circuit model and Arrhenius law were used to calculate the activation energy of grain and grain boundary, which indicated that the dielectric relaxation at high temperature was caused by oxygen vacancy. While appropriate SiO₂ additive led to improve the breakdown strength, further increase of SiO₂ deteriorated the energy storage because of the low densification. Finally, optimized energy storage performance was obtained for BSTS0.5 ceramics: dielectric constant of 1002, dielectric loss of 0.45%, energy density of 0.86 J/cm³ and energy storage efficiency of 79% at 134 kV/cm.     

The structures and dielectric properties of Ba0.80Sr0.20TiO3/Pb0.82La0.18TiO3 composite thick films with addition of PbO–B2O3 glass

Sol–gel derived Ba_0.80Sr_0.20TiO₃ (BST) and Pb_0.82La_0.18TiO₃ (PLT) powders and a low-melting PbO–B₂O₃ glass powder were mixed to prepare paste. The composite thick films (∼40 μm) were fabricated by screen-printing the paste onto the Al₂O₃ substrates with screen-printed silver bottom electrode and then sintered at the low temperature 650–800 °C, respectively. X-ray diffraction (XRD), transmission microscope (TEM), scanning electron microscope (SEM) and an impedance analyzer were used to analyze the structures, microstructures and dielectric properties of the powders and the composite thick films. The results show that the composite thick films containing sol–gel derived Ba_0.80Sr_0.20TiO₃ and Pb_0.82La_0.18TiO₃ perovskite phases have been fabricated by using the PbO–B₂O₃ glass as a sintering aid. Compared to conventional sintering at ≥1200 °C, high densification of the composite thick films is achieved at temperature as low as 800 °C by the “wetting” and “infiltration” of the liquid phase on the particles. The homogenization of the BST and PLT perovskite phase in the composite thick films is evitable by controlling the sintering temperature and time. The formation of the small amount of pyrochlore phase in composite thick films sintered at 800 °C is resulted from both the volatilization of PbO and the interaction between the PLT and PbO–B₂O₃ glass. The relative dielectric properties of the composite thick films exhibit good temperature-stable behavior, and the variation of the relative dielectric constant is less than 10% in the temperature range 0–300 °C.     

Reduced leakage current,enhanced energy storage and dielectric properties in (Ce,Mn)-codoped Ba0.6Sr0.4TiO3 thin film

Ba_0.6Sr_0.4TiO₃, Ce-doped Ba_0.6Sr_0.4TiO₃, Mn-doped Ba_0.6Sr_0.4TiO₃, (Ce,Mn) co-doped Ba_0.6Sr_0.4TiO₃ (abbreviated as BST, BSTCe, BSTMn, BSTCeMn) thin films were deposited on LaNiO₃(LNO)/Si substrates. The effects of ion doping on the microstructure and electrical properties of BST-based thin film have been researched and discussed. The X-ray diffraction pattern shows that each sample has pure perovskite phase structure with high (l00) peaks. The microstructure of each film is quite dense with uniform size. Compared with pure BST, improved insulating properties can be found in ion-doped BST thin films. For all the films, Ohmic conduction, space charge limited conduction and interface-limited Fowler-Nordheim tunneling should be the main conduction mechanisms within different electric field regions. For the case of BSTCeMn thin film, it possesses enhanced energy storage performance with a recoverable energy storage density (18.01?J/cm³) and a energy storage efficiency (75.1%) under 2000?kV/cm. This can be closely related to the small remanent polarization value (P_r=?1.89 μC/cm²), large maximum polarization value (P_max=?28.08?μC/cm²) as well as big maximum electric field (2000?kV/cm). Also, it exhibits a large dielectric constant of 405 and a small dissipation factor of 0.075 at 500?kHz.     

In situ doping of BaTiO3 and visualization of pressure solution in flux-assisted cold sintering

Cold sintering process (CSP) has attracted great interest due to its extremely low processing temperatures, fast processing times, and simplicity to allow for the densification of ceramics and composites. Understanding the detailed mechanisms underlying low temperature densification is crucial to develop advanced materials and facilitate sustainable and cost-effective industrial implementation to come. Here, by taking BaTiO₃ powder and Sr(OH)₂·8H₂O transient chemical flux as a model system, chemical transformation at solid/flux interfaces driving the dissolution-precipitation creep mechanism were investigated. We demonstrate that Sr(OH)₂·8H₂O acts both as a sintering flux and a solid solution doping additive, resulting in the formation of BaTiO₃ - Ba_1-xSr_xTiO₃ with lower Curie temperatures. Using strontium (Sr) as a tracer chemistry, transmission electron microscopy chemical mapping with energy-dispersive X-ray analysis indicates that there is a precipitation of a Ba_1-xSr_xTiO₃ mainly at grain/grain interfaces, while grain cores remain undoped. In addition, the difference in the interfacial Sr concentration, which is influenced by the applied uniaxial pressure direction, was clearly observed. This successful visualization of compositional distribution after CSP underlines the significant role of the pressure solution creep in densification process.     

Low-temperature synthesis of superfine barium strontium titanate powder by the citrate method

Ba_0.6Sr_0.4TiO₃ powder was synthesized by a citrate method. The phase development was examined with respect to calcining temperature and heating rate during the calcining process. The results reveal a crucial role of the heating rate to the formation of a pure perovskite phase at low calcining temperatures. It was found that keeping relatively low heating rates ≤0.7 °C/min during the calcining process after 300 °C was favorable to a sufficient decomposition of (Ba,Sr)₂Ti₂O₅·CO₃ intermediate phase at low temperatures and consequently led to the formation of a pure perovskite phase at 550 °C. Ba_0.6Sr_0.4TiO₃ powder calcined at the temperature under the heating rate of 0.7 °C/min showed a superfine and uniform particle morphology and high sintering reactivity. As a result, the ceramic specimens prepared from the powder attained reasonable relative densities (94–95%) at sintering temperatures of 1250–1270 °C.