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1.
Defect engineering on phase structure and temperature stability of KNN‐based ceramics sintered in different atmospheres
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Zhenyong Cen Xiaohui Wang Yu Huan Yichao Zhen Wei Feng Longtu Li 《Journal of the American Ceramic Society》2018,101(7):3032-3043
Lead‐free MnO‐doped 0.955K0.5Na0.5NbO3‐0.045Bi0.5Na0.5ZrO3 (Abbreviated as KNN‐0.045BNZ) ceramics have been prepared by the conventional solid‐state sintering method in reducing atmosphere ( = 1 × 10?10 atm) and air. For ceramics sintered in reducing atmosphere, only Mn2+ ions exist in ceramics who preferentially occupy the cation vacancies in A‐site at x = 0.2‐0.4, whereas Mn2+ ions substitute for Zr4+ ions in B‐site to form defects () at x > 0.4. For ceramics sintered in air, mixed Mn2+, Mn3+, and Mn4+ ions coexist here. The Mn2+ ions preferentially occupy the cation vacancies in A‐site at x = 0.2‐0.4 and then Mn2+ ions substitute for Zr4+ ions in B‐site at x > 0.4. Meanwhile, the Mn3+ ions and Mn4+ ions substitute for Nb5+ ions in B‐site to form defects () at x = 0.2‐0.8. The (, , and ) dipolar defects show a positive dipolar defect contribution (DDC) to the , whereas the dipolar defects () show a negative DDC to the . The dipolar defects ( ‐ and ) can help improve the temperature stability of . The 0.4% MnO‐doped KNN‐0.045BNZ ceramics sintered in reducing atmosphere show excellent piezoelectric constant d33 = 300 pC/N and 0.2% MnO‐doped KNN‐0.045BNZ ceramics sintered in air possess optimal piezoelectric constant d33 = 290 pC/N. 相似文献
2.
Tatsuo Kumagai 《Journal of the American Ceramic Society》2013,96(3):852-858
The rapid densification behavior of 8 mol% Y2O3‐stabilized ZrO2 polycrystalline (8Y‐SZP) powder compacts at the initial stage of pressure sintering (relative density () below 0.92) has been investigated using an electric current‐activated/assisted sintering (ECAS) system. Data points corresponding to a fixed heating rate were extracted from the densification rate () versus ρ and versus temperature (T) curves. These curves were obtained experimentally by consolidation at a fixed current. Under fixed current ECAS, the heating rate () decreases continuously over sintering time. Using a quasi‐ constant heating rate (CHR) method, data points were extracted to plot vs. ρ, vs. T, and ρ vs. T curves at a fixed . The stress exponent (n), estimated from a log‐log plot of grain size (d)‐corrected /ρ and effective stress (σeff) at 1300–1400 K, shows an almost constant value of 1. In addition, the activation energy (Q) for rapid densification, estimated from an Arrhenius plot of d‐corrected /ρ also shows an almost constant value of 350 kJ/mol, which is considerably lower than the previously reported value of the activation energy for Zr4+ lattice diffusion of about 440 kJ/mol. These results suggest that rapid densification of 8Y‐SZP by ECAS seems to proceed by diffusional creep controlled by grain‐boundary diffusion of Zr4+ ions. 相似文献
3.
A piezomicrobalance system for high‐temperature mass relaxation characterization of metal oxides: A case study of Pr‐doped ceria
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Philipp Simons Ho‐Il Ji Timothy C. Davenport Sossina M. Haile 《Journal of the American Ceramic Society》2017,100(3):1161-1171
A system for mass relaxation studies based on a gallium phosphate piezocrystal microbalance has been developed, built, and successfully used to characterize a representative mixed ionic and electronic conducting material. The apparatus is constructed to achieve reactor gas exchange times as short as 2 seconds and temporal resolution in mass measurement of 0.1 seconds. These characteristics enabled evaluation of mass relaxations that occurred on the 6 seconds time scale. Proof of concept for materials characterization capabilities of the system was carried out using 10% praseodymium‐doped cerium oxide (PCO), a material that undergoes, at selected temperatures and oxygen partial pressures, changes in mass but not in conductivity. Thin films were deposited on the piezocrystals via pulsed laser deposition (PLD). Mass relaxation curves were collected at 700°C upon application of a small step change in oxygen partial pressure, . Using two different films, the surface reaction constant, kS, was obtained over the range from 10?4 to 0.1 atm. Its value is found to vary between 9.7 × 10?6 and 1.7 × 10?4 cm/s, displaying a power law dependence on , with a law exponent of 0.67 ± 0.02, as averaged over the two sets of results. This steep dependence of kS on is surprisingly independent of a change in dominant defect type within the range of measurement. 相似文献
4.
Effect of the (Ba + Sr)/Ti ratio on the microwave‐tunable properties of Ba0.6Sr0.4TiO3 ceramics
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Takashi Teranishi Riku Kanemoto Hidetaka Hayashi Akira Kishimoto 《Journal of the American Ceramic Society》2017,100(3):1037-1043
The impact of the (Ba + Sr)/Ti (A/B) ratio on the microwave‐tunable characteristics of diffuse phase transition (DPT) ferroelectric Ba0.6Sr0.4TiO3 (0.6‐BST) ceramics was investigated. The reduction in the lattice constant with increasing nonstoichiometry was attributed to introduced partial Schottky defects, i.e., and . The magnitude of the dielectric constant, ε′, at room temperature in the absence of an applied electric field was governed by the shift in the dielectric maximum temperature, Tm, because Tm was close to room temperature for the 0.6‐BST. The dielectric loss, tanδ, diminished as the ε′ decreased for 0.98≤A/B≤1.05, while the tanδ was much higher for A/B=0.95 having the greatest A‐site vacancy loading. The negatively charged and were mainly compensated by oxygen vacancies and likely partly compensated by holes, h?, which contributed to the electrical conduction. The tunability, T, at 100 MHz was almost constant at 20%–25% for A/B≥1.00 despite the reduction of the ε′, whereas T decreased for A/B<1.00 to ca. 10% for A/B=0.95 having the greatest A‐site vacancy loading. The results implied that the for larger A/B values was more efficient in generating nucleation sites in the polar nanoregions (PNRs) than the for smaller A/B values, thereby providing greater dipole polarization. Consequently, the figure of merit, FOM, reached its maximum of 250 at A/B=0.9875, which was ca. 155% higher than that of the stoichiometric BST. 相似文献
5.
Malahalli Vijaya Kumar Kazuhiko Kuribayashi Jianding Yu Junpei.T. Okada Takehiko Ishikawa 《Journal of the American Ceramic Society》2013,96(3):995-1002
Containerless levitation technique, where the undercooling can be treated as one of the major thermodynamic parameters, was used to study the influence of oxygen partial pressure () on the microstructure and physical properties of rare‐earth orthoferrites RFeO3 (where R = Rare‐earth element) in the ranges from 105 to 10?1 Pa. The microstructure of the as‐solidified samples changed into orthorhombic RFeO3 (o‐RFeO3), metastable hexagonal RFeO3 (h‐RFeO3), and Fe2+‐containing RFe2O4 and a new metastable R3Fe2O7 phases with decreasing . The effect of on the magnetic properties was indicated as that the saturation magnetization gradually increased for R = La to Yb and decreased for R = Lu with decreasing due to the formation of metastable and magnetic phases such as Fe3O4 and Fe. 相似文献
6.
Composition‐induced structural transitions and enhanced strain response in nonstoichiometric NBT‐based ceramics
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Xing Liu Feng Li Jiwei Zhai Bo Shen Peng Li Baihui Liu 《Journal of the American Ceramic Society》2017,100(8):3636-3645
In this work, the nonstoichiometric 0.99Bi0.505(Na0.8K0.2)0.5‐xTiO3‐0.01SrTiO3 (BNKST(0.5‐x)) ceramics with x=0‐0.03 were synthesized by conventional solid‐state reaction method. The composition‐induced structural transitions were investigated by Raman spectra, dielectric analyses, and electrical measurements. It is found that the relaxor phase can be induced through the modulation of the (Na, K) content. The (Na, K) deficiency in BNKST(0.5‐x) ceramics favors a more disordered local structure and can result in the loss of long‐range ferroelectricity. The x=0.015 critical composition possesses relatively high positive strain Spos of 0.42% and large signal piezoelectric constant d33* of 479 pm V?1 at 6 kV mm?1, along with the good temperature (25‐120°C) and frequency (1‐20 Hz) stability. The recoverable large strain responses in nonstoichiometric ceramics can be attributed to the reversible relaxor‐ferroelectric phase transition, which is closely related to the complex defects (, , and ) and the local random fields. This work may be helpful for the exploration of high‐performance NBT‐based lead‐free materials by means of A‐site compositional modification. 相似文献
7.
Presented are new measurements of the standard Gibbs free energy of formation of rhombohedral LaCrO3 from component oxides La2O3 and Cr2O3 in the temperature range from 875 to 1175 K, using a bielectrolyte solid‐state cell incorporating single crystal CaF2 and composition‐graded solid electrolyte (LaF3)y·(CaF2)1?y (y = 0–0.32). The results can be represented analytically as (±2270)/J·mol?1 = ?72329 + 4.932 (T/K). The measurements were undertaken to resolve serious discrepancies in the data reported in the literature. A critical analysis of previous electrochemical measurements indicates several deficiencies that have been rectified in this study. The enthalpy of formation obtained in this study is consistent with calorimetric data. The standard enthalpy of formation of orthorhombic LaCrO3 from elements at 298.15 K computed from the results of this study is /kJ·mol?1 = ?1536.2 (±7). The standard entropy of orthorhombic LaCrO3 at 298.15 K is estimated as 99.0 (±4.5) J·(mol·K)?1. 相似文献
8.
Temperature stability and electrical properties of MnO‐doped KNN‐based ceramics sintered in reducing atmosphere
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Zhenyong Cen Xiaohui Wang Yu Huan Longtu Li 《Journal of the American Ceramic Society》2018,101(6):2391-2407
Lead‐free MnO‐doped 0.955K0.5Na0.5NbO3‐0.045Bi0.5Na0.5ZrO3 (abbreviate as KNN‐0.045BNZ) ceramics have been prepared by a conventional solid‐state sintering method in reducing atmosphere. The MnO addition can suppress the emergence of the liquid phase and improve the homogenization of grain size. All ceramics sintered in reducing atmosphere show a two‐phase coexistence zone composed of rhombohedral (R) and tetragonal (T) phase. MnO dopant results in the content increase in R phase and slight increase in Curie temperature TC. For KNN‐0.045BNZ ceramics, Mn2+ ions preferentially occupy the cation vacancies in A‐site to decrease oxygen vacancy concentration for 0.2%‐0.4% MnO content, whereas Mn2+ ions substitute for Zr4+ ions in B‐site to form oxygen vacancies at x ≥ 0.5. The defect dipole is formed at the moderate concentration from 0.5 to 0.6, which can provide a preserve force to improve the temperature stability of piezoelectric properties for kp and . The Mn0.4 ceramics show excellent electrical properties with quasistatic piezoelectric constant d33 = 300 pC/N, electromechanical coupling coefficient kp = 51.2%, high field piezoelectric constant = 430 pm/V (at Emax = 25 kV/cm) and TC = ~345°C, insulation resistivity ρ = 6.13 × 1011 Ωcm. 相似文献
9.
Kazimierz Kowalski Katarzyna Obal Zbigniew Pedzich Krystyna Schneider Mieczyslaw Rekas 《Journal of the American Ceramic Society》2014,97(10):3122-3127
Aluminum oxide was deposited on the surface of 3 mol% yttria‐stabilized tetragonal zirconia polycrystals (3Y‐TZP). The samples were annealed at temperatures from 1523 to 1773 K. Diffusion profiles of Al in the form of mean concentration vs. depth in B‐type kinetic region were investigated by secondary ion mass spectroscopy. The experimental results for the lattice diffusion (DB) and grain boundary diffusion (DGB) are as follows: and where δ is the grain‐boundary width and s is the segregation factor. 相似文献
10.
Electrical Properties and Relaxor Phase Evolution of Li‐Modified BNT‐BKT‐BT Lead‐Free Ceramics
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Ye‐Jing Dai Zhe Zhao Xiao‐Wen Zhang Si‐Hui Wang 《Journal of the American Ceramic Society》2016,99(7):2354-2360
By conventional ceramics sintering technique, the lead‐free 0.85Bi0.5Na0.5(1?x)Li0.5xTiO3‐0.11Bi0.5K0.5TiO3‐0.04BaTiO3 (x =0–0.15) piezoelectric ceramics were obtained and the effects of Li dopant on the piezoelectric, dielectric, and ferroelectric properties were studied. With increasing Li addition, the temperature‐dependent permittivity exhibited the normal ferroelectric‐to‐ergodic relaxor (FE‐to‐ER) transition temperature (TFE‐ER, abbreviated as TF‐R) decreasing down to room temperature. The increasing Li content also enhanced the diffuseness of the FE‐to‐ER transition behavior. For composition with x = 0.15, a large unipolar strain of 0.37% ( = Smax/Emax = 570 pm/V) was achieved under 6.5 kV/mm applied electric field at room temperature. Both unipolar and bipolar strain curves related to the temperature closely, and when the temperature reached the TF‐R, the normalized strain achieved a maximum value (e.g., for x = 0.10, = 755 pm/V) owing to the electric‐field‐induced ER‐to‐FE state transition. 相似文献
11.
First‐principles investigation of the thermodynamic stability of MB2 materials surfaces (M = Ti/Zr/Hf)
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Some of the renewed interest in transition metal diborides (MB2, M = Ti/Zr/Hf) arises from their potential use as matrices in ultrahigh‐temperature ceramic matrix composites (UHTCMCs). Crucial to the understanding of such composites is the study of the fiber/matrix interfaces, which in turn requires a deep knowledge of the surface structures and the thermodynamics of the matrix material. Here we investigate the surface stability of MB2 compounds by first‐principles calculations. Five surfaces are stabilized when going from a M‐rich to a B‐rich environment, respectively (0001)M, (100)M, (101)B(M), (113)M and (0001)B, with the highly stable (100)M, (101)B(M) and (113)M surfaces being discussed here for the first time. The mechanism behind the surface stability is analyzed in terms of cleavage energy, surface strain and surface bonding states. Our results provide important information for a better understanding of the most likely surfaces exposed to the fibers in UHTCMCs, thereby for the construction of reliable interfaces and ultimately UHTCMCs models. 相似文献
12.
First‐Principles Study of Sc1−xTixF3 (x ≤ 0.375): Negative Thermal Expansion,Phase Transition,and Compressibility
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Lei Wang Cong Wang Ying Sun Sihao Deng Kewen Shi Huiqing Lu Pengwei Hu Xiaoyun Zhang 《Journal of the American Ceramic Society》2015,98(9):2852-2857
We present the first‐principles investigation of (x ≤ 0.375). Controllable thermal expansion of is achieved by different Ti contents. The negative thermal expansion (NTE) behavior is weakened gradually with increasing Ti content, which is consistent with experimental measurements. The Jahn–Teller effect plays an important role in the cubic‐to‐rhombohedral phase transition, which stems from the enhanced energy stability when the 3d orbitals of cation split into triply degenerate and sets. The unusual thermal stiffening of is found, which is similar to that of and but contrary to other NTE materials. 相似文献
13.
Jonathan M. Polfus Wen Xing Marit Riktor Martin F. Sunding Paul Inge Dahl Sidsel M. Hanetho Tommy Mokkelbost Yngve Larring Marie‐Laure Fontaine Rune Bredesen 《Journal of the American Ceramic Society》2016,99(3):1071-1078
Dense symmetric membranes of CaTi0.85?xFe0.15MnxO3?δ (x = 0.1, 0.15, 0.25, 0.4) are investigated in order to determine the optimal Mn dopant content with respect to highest O2 flux. O2 permeation measurements are performed as function of temperature between 700°C–1000°C and as function of the feed side ranging between 0.01 and 1 bar. X‐ray photoelectron spectroscopy is utilized to elucidate the charge state of Mn, and synchrotron radiation X‐ray powder diffraction (SR‐XPD) is employed to investigate the structure symmetry and cell volume of the perovskite phase at temperatures up to 800°C. The highest O2 permeability is found for x = 0.25 over the whole temperature and ranges, followed by x = 0.4 above 850°C. The O2 permeability for x = 0.25 reaches 0.01 mL(STP) min?1 cm?1 at 925°C with 0.21 bar feed side and Ar sweep gas. X‐ray photoelectron spectroscopy indicates that the charge state of Mn changes from approx. +3 to +4 when x > 0.1, which implies that Mn mainly improves electronic conductivity for x > 0.1. The cell volume is found to decrease linearly with Mn content, which coincides with an increase in the activation energy of O2 permeability. These results are consistent with the interpretation of the temperature and dependency of O2 permeation. The sintering behavior and thermal expansion properties are investigated by dilatometry, which show improved sinterability with increasing Mn content and that the thermal expansion coefficient decreases from 12.4 to 11.9 × 10?6 K?1 for x = 0 and x = 0.25, respectively. 相似文献
14.
Bin Liu Benjamin Petersen Yanwen Zhang Jingyang Wang William J. Weber 《Journal of the American Ceramic Society》2016,99(8):2693-2698
Low‐energy recoil events in Ti3SiC2 are studied using ab initio molecular dynamics simulations. We find that the threshold displacement energies are orientation dependent because of anisotropic structural and/or bonding characteristic. For Ti and Si in the Ti–Si layer with weak bonds that have mixed covalent, ionic, and metallic characteristic, the threshold displacement energies for recoils perpendicular to the basal planes are larger than those parallel to the basal planes, which is an obvious layered‐structure‐related behavior. The calculated minimum threshold displacement energies are 7 eV for the C recoil along the direction, 26 eV for the Si recoil along the direction, 24 eV for the Ti in the Ti–C layer along the direction and 23 eV for the Ti in the Ti–Si layer along the direction. These results will advance the understanding of the cascade processes of Ti3SiC2 under irradiation and are expected to yield new perspective on the MAX phase family that includes more than 100 compounds. 相似文献
15.
Takashi Teranishi Koji Osaki Hidetaka Hayashi Akira Kishimoto 《Journal of the American Ceramic Society》2018,101(2):723-731
Domain engineering via oxygen vacancy, , loading achieved by A/B modification as well as quenching treatment, was utilized for Ba0.8Sr0.2TiO3 (0.8 BSTs) in an attempt to enhance the microwave tunable characteristics. For similar grain sizes, the domain sizes were notably reduced for all nonstoichiometric BSTs, indicating that the loaded (as a consequence of Ti defects, ) played a role in the nuclei for new domain walls. The tunability T at 100 MHz under a direct current field of 30 V/20 μm increased steadily as the domain size (d.s.) declined for all BSTs, regardless of the A/B ratio, due to the d.s. effect. The tunable characteristics in nonstoichiometric BSTs having a similar d.s. of ?190 nm were then compared. The tunability and tan δ decreased for A/B = 1.002 (0.2 mol% Ti defects). The introduced formed pinning centers that restricted domain wall motion, leading directly to lower tunability and smaller dielectric loss. However, ‐overloaded samples (i.e., A/B ≥ 1.005) exhibited increased values for tan δ due to conduction in the domains. The quench treatment of 0.8 BST (with A/B = 1.002) samples resulted in a d.s. reduction from 191 to 170 nm. These quenched specimens showed greater tunability, Ttotal, originating from the strengthened dipole contribution, Tdipole, as a consequence of the d.s. effect. The tan δ of the quenched specimens was essentially unchanged, indicating a homogenous distribution via the quench, effectively reducing the mobile (which contributes to electrical conduction) in the domains. Consequently, the achieved figure of merit via domain engineering was 2.25 at 100 MHz for the quenched BST with A/B = 1.002, which was 1.54 times larger than that of unmodified BST. 相似文献
16.
Jongseong Park Dae‐Hyeon Kim Su‐Jin Park Tae‐gon Lee Mir Im Jeong‐Seog Kim Sahn Nahm 《Journal of the American Ceramic Society》2016,99(7):2229-2232
A specimen having a stoichiometric composition of KSbO3·(KSb) calcined at 800°C has an R rhombohedral structure (RS), and changes to a Pn cubic structure (CS) when calcined at 1100°C. Finally, a <111>‐oriented rhombohedral phase is formed in the specimen calcined at 1230°C. K/Sb ratio decreases from 1.0 in RS, 0.93 in CS, and finally to 0.85 in <111>‐oriented rhombohedral phases. On the other hand, a specimen having a K‐excess composition of K1.1SbO3 calcined at 800°C shows a RS that is maintained in the K‐excess specimen calcined at 1230°C. The composition of these specimens is very close to KSb. Therefore, the RS with a space group of R is a stable form of KSbO3. The formation of Pn cubic and <111>‐oriented R phases can be explained by the evaporation of K2O during the calcination process at temperatures above 1100°C. 相似文献
17.
Y. Kubota H. Hatta T. Yoshinaka Y. Kogo T. Goto T. Rong 《Journal of the American Ceramic Society》2013,96(4):1317-1323
Quantitative evaluation of oxidation behavior of high‐temperature materials is imperative for applications in a Silicon carbide (SiC)‐based thermal protection system (TPS) of reentry space vehicles. However, the reported oxidation rates obtained using thermogravimetric analysis (TGA) have been widely varied among researchers. In this study, this variation is assumed to be attributable to differences in the oxygen partial pressure at the sample surface due to different configuration of the experimental devices. Existing data are usually given as a function of the surface temperature of a specimen TS with the partial pressure of oxygen in the input gas as a main parameter. However, even if and TS are set to the same, the oxygen partial pressure on specimen surface and gas temperature TG are expected to vary widely, respectively, from , TS, and according to the difference in the oxidative environments. To evaluate these effects in various apparatuses, numerical calculations were conducted for the case of SiC. From these results, was found to be main source of the variation in oxidation rates. 相似文献
18.
Yu Shi Bao‐Wei Li Ming Zhao Ming‐Xing Zhang 《Journal of the American Ceramic Society》2018,101(9):3968-3978
CaO–Al2O3–MgO–SiO2 (CAMS)‐based glass‐ceramics were prepared using body crystallization method. Adding Cr2O3 into the ceramics not only effectively lowered the crystallization temperature, but also led to significant grain refinement of diopside that crystallized in the CAMS glass‐ceramic after crystallization treatment at 900°C for 2 hours. Experimental work verified that the epitaxial growth of the diopside on the spinel particles, which formed during nucleation treatment when fabricating the glass‐ceramics, facilitated the heterogeneous nucleation of diopside on the spinel and refined the diopside. In addition, two energetically favored crystallographic orientation relationships between the epitaxial growth diopside and spinel were experimentally observed. They are //[001]diopside,////(200)diopside and //[101]diopside, (311)spinel//. These two novel results can be potentially used to develop new glass‐ceramic materials with improved performance. 相似文献
19.
Structure and Microwave Dielectric Behavior of A‐Site‐Doped Sr(1−1.5x)CexTiO3 Ceramics System
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Burhan Ullah Wen Lei Qing‐Song Cao Zheng‐Yu Zou Xue‐Kai Lan Xiao‐Hong Wang Wen‐Zhong Lu 《Journal of the American Ceramic Society》2016,99(10):3286-3292
The ion valence state, phase composition, microstructure, and microwave dielectric properties of Sr(1?1.5x)CexTiO3 (x = 0.1–0.67, SCT) ceramics were systematically investigated. Sr(1?1.5x)CexTiO3 ceramics were produced with gradual structural evolution from a cubic to a tetragonal and turned to an orthorhombic structure in the range of 0.1 ≤ x ≤ 0.67. Above a critical Ce proportion (x = 0.4), microstructural changes and normal grain growth initially occurred. On the basis of chemical analysis results, the reduction of Ti4+ ions was hastened by tetravalent ions (Ce4+). By contrast, this reduction was inhibited by trivalent ions (Ce3+). The observed dielectric behavior was strongly influenced by phase composition, oxygen vacancies (), and defect dipoles, namely, () and (). Temperature stable ceramics sintered at 1350°C for 3 h in air yielded an intermediate value of dielectric constant (εr = 40), with the smallest reported value of temperature coefficient of resonant frequency (τf = +0.9 ppm/°C), and quality factor (Q × f = 5699 GHz) at x = 0.6. 相似文献
20.
Joon Sung Choi Youngjoo Park Sunghee Lee Dong Joon Min 《Journal of the American Ceramic Society》2018,101(7):2856-2867
The effect of CaO on the sulfide capacity of CaO‐Al2O3‐SiO2 slags was studied from the viewpoint of the ionic structure of alumina in slag. The aluminum coordination number was analyzed using 27Al 500‐MHz solid nuclear magnetic resonance spectroscopy and the results were compared with those of the sulfide capacity analysis. The sulfide capacity of slag, in the peralkaline region (), exhibited a linear relationship with respect to basicity () as excess free Ca2+ formed a 4‐coordinated aluminum unit structure ([IV]Al; ) and stabilized the sulfide ions (). However, sulfide capacity in the peraluminous region () exhibited a nonlinear relationship with respect to basicity () owing to the structure of higher‐coordinated aluminum units ([V]Al, [VI]Al; Al3+) and the relative lack of Ca2+. Therefore, the sulfide capacity of high Al2O3‐bearing slags strongly depended on the basicity () and stability of sulfide ions (), which depended on the competitive behavior of Ca2+ owing to the structural changes in Al2O3. The effect of the aluminum coordination number on the sulfide capacity was discussed in detail using an analysis of the slag structure and thermodynamics model. 相似文献