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1.
《Ceramics International》2023,49(18):30224-30229
Dense MgO–12% TiO2(w) ceramics containing 12 wt% TiO2, which were doped with Li2CO3–Bi2O3 composite sintering aids, were prepared at a low sintering temperature of 950 °C in this study. The effects of sintering additives on the sintering characteristics, phase composition, microstructure, and dielectric and mechanical properties of the ceramic samples were systematically investigated, and the influences of their phase composition and microstructure on the dielectric and mechanical properties were examined. The introduction of sintering aids produced a new Bi4Ti3O12 phase in the sample structure, while the residual Bi2O3 mixed with the newly formed Mg2TiO4 and Bi4Ti3O12 phases distributed at MgO grain boundaries formed a structure surrounding MgO grains. This structure filled the pores in the ceramic sample, which increased its density and enhanced the mechanical properties. At a Li2CO3–Bi2O3 content of 15 wt%, the density, flexural strength, and Vickers hardness of the ceramic samples reached their maximum values of 3.4 g/cm3, 218.9 MPa, and 778.7 HV, respectively. However, the further increase in the Li2CO3–Bi2O3 content deteriorated their dielectric properties although the dielectric constant and dielectric loss remained below 13.4 and 2.1 × 10−3, respectively. The findings of this work indicate that Li2CO3–Bi2O3 sintering aids can significantly lower the sintering temperature of MgO–12% TiO2(w) ceramics and control their dielectric and mechanical properties through microstructural changes. 相似文献
2.
《Ceramics International》2021,47(19):27545-27552
B2O3 and CuO were codoped into 6Nd[(Zn0.7Co0.3)0.5Ti0.5]O3–4(Na0.5Nd0.5)TiO3 (abbreviated as 6NZCT–4NNT) ceramics as sintering aids. The influences of the sintering aids on the sintering characteristics, microstructure and microwave dielectric properties of the 6NZCT–4NNT ceramics were systematically investigated as a function of the proportion of B2O3 and CuO. Codoping could greatly reduce the sintering temperature from 1410 °C to 1150 °C, indicating that B2O3/CuO are good sintering aids for 6NZCT–4NNT ceramics. The B2O3/CuO sintering aids had no significant impact on the phase purity of the investigated ceramics, even though a solid solution was formed due to Cu2+ ion substitution. However, they had evident influences on the surface morphology and grain size. The average grain size was enlarged with increasing amounts of CuO in the B2O3/CuO sintering aids. Remarkable deterioration of the microwave dielectric properties for 6NZCT-4NNT ceramics was not observed when codoping an appropriate amount of B2O3 and CuO. The 6NZCT–4NNT ceramics codoped with 2.0 mol% B2O3 and 2.0 mol% CuO sintered at 1150 °C for 3 h exhibited a homogeneous microstructure and promising microwave dielectric properties: an appropriate dielectric constant (εr = 49.37), a high quality factor (QF = 47,295 GHz), and a near-zero temperature coefficient of resonant frequency (TCF = +0.9 ppm/°C). 相似文献
3.
Yusen Duan Jingxian Zhang Xiaoguang Li Hainan Bai Pavol Sajgalik Dongliang Jiang 《International Journal of Applied Ceramic Technology》2019,16(4):1399-1406
Silicon nitride ceramics were pressureless sintered at low temperature using ternary sintering additives (TiO2, MgO and Y2O3), and the effects of sintering aids on thermal conductivity and mechanical properties were studied. TiO2–Y2O3–MgO sintering additives will react with the surface silica present on the silicon nitride particles to form a low melting temperature liquid phase which allows liquid phase sintering to occur and densification of the Si3N4. The highest flexural strength was 791(±20) MPa with 12 wt% additives sintered at 1780°C for 2 hours, comparable to the samples prepared by gas pressure sintering. Fracture toughness of all the specimens was higher than 7.2 MPa·m1/2 as the sintering temperature was increased to 1810°C. Thermal conductivity was improved by prolonging the dwelling time and adopting the annealing process. The highest thermal conductivity of 74 W/(m∙K) was achieved with 9 wt% sintering additives sintered at 1810°C with 4 hours holding followed by postannealing. 相似文献
4.
The liquid phase screening method was used to search for sintering aids for 0.88(Bi0.4K0.2Na0.2Ba0.2)TiO3–0.12Sr(Mg1/3Nb2/3)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. 相似文献
5.
Xiao-Tong Jia Zhao-Hui Zhang Tian-Hao Xu Luo-Jin Liu Yuan-Hao Sun Xian-Yu Li Qiang Wang Zhao-Hu Jia Yang-Yu He Xing-Wang Cheng 《Journal of the American Ceramic Society》2023,106(10):6301-6316
Aluminum oxynitride (AlON) ceramics doped with different sintering aids were synthesized by spark plasma sintering process. The microstructures, mechanical, and optical properties of the ceramics were investigated. The results indicate that the optimal amount of sintering aids is 0.06 wt% La2O3 + 0.16 wt% Y2O3 + 0.30 wt% MgO. The addition of La3+ and Mg2+ decreases the rate of grain boundary migration in ceramics, promotes pore elimination, and inhibits grain growth. The addition of Y3+ facilitates liquid-phase sintering of AlON ceramics. Moreover, the addition of Mg2+ effectively promotes twin formation in the ceramics, which hinders crack propagation and dislocation motion when the ceramics are loaded. Hence, the AlON ceramic doped with 0.06 wt% La2O3 + 0.16 wt% Y2O3 + 0.30 wt% MgO exhibits a relative density of 99.95%, an average grain size of 9.42 μm, and a twin boundary content of 10.3%, which contributes to its excellent mechanical and optical properties. 相似文献
6.
A ternary solid-solution piezoelectric ceramic of rare-earth oxides modified 0.03 Pb(Mn1/3Sb2/3)O3-0.97 Pb(Zr0.505Ti0.495)O3 + x wt.% CuO + y wt.% Bi2O3 (PMS-PZT + x wt.% CuO + y wt. % Bi2O3) (x, y = 0–0.2) was successfully prepared via a transient-liquid-phase sintering. Both Cu2+ and Bi3+ were believed to replace the A-site Pb ions and to evidently induce the lattice shrinkage and the distortion decrease. However, the addition of only a small amount of CuO was found to effectively reduce the sintering temperature, sustain good piezoelectric properties and predominant transgranular fracture modes, but obviously increase the average grain size and high-field dielectric loss. Further experimental results indicate that the grain growth of the ceramics was inhibited effectively and the high-field dielectric loss was reduced through CuO and Bi2O3 co-doping. The 0.05 wt% CuO and 0.15 wt% Bi2O3 co-doped PMS-PZT ceramics sintered at 1050 °C exhibit excellent dielectric and piezoelectric properties of d33 = 410 pC/N, kp = 0.62, Qm = 1478, εr = 1550, tan δ = 0.8% (400 V/mm) and Tc = 330 °C. The experimental results can provide a solid fundament for multilayer piezoelectric actuating devices. 相似文献
7.
Pallavi Suhasinee Behera Sunipa Bhattacharyya 《International Journal of Applied Ceramic Technology》2021,18(1):81-90
Mullite ceramic was prepared using kaolinite and synthesized alumina (combustion route) by solid-state interaction process. The influence of TiO2 and MgO additives in phase formation, microstructural evolution, densification, and mechanical strengthening was evaluated in this work. TiO2 and MgO were used as sintering additives. According to the stoichiometric composition of mullite (3Al2O3·2SiO2), the raw materials, ie kaolinite, synthesized alumina, and different wt% of additives were wet mixed, dried, and uniaxially pressed followed by sintering at different temperature. 1600°C sintered samples from each batch exhibit enhanced properties. The 1 wt% TiO2 addition shows bulk density up to 2.96 g/cm3 with a maximum strength of 156.3 MPa. The addition of MgO up to 1 wt% favored the growth of mullite by obtaining a density and strength matching with the batch containing 1 wt% TiO2. These additives have shown a positive effect on mullite phase formation by reducing the temperature for complete mullitization by 100°C. Both additives promote sintering by liquid phase formation. However, the grain growth, compact microstructure, and larger elongated mullite crystals in MgO containing batch enhance its hardness properties. 相似文献
8.
《Ceramics International》2016,42(9):10690-10696
PLZT 9/65/35 (Pb0.91La0.09(Zr0.65Ti0.35)0.9775O3) ceramics with addition of 0.25, 0.5 and 1.0 wt% of Bi2O3/CuO (where the ratio of Bi2O3:CuO=9:1 by mole) were prepared by sintering at the temperatures between 1000 and 1200 °C. It was found that Bi2O3/CuO could bring the sintering temperature down ~50 °C to obtain PLZT with no second phase. Dielectric and ferroelectric properties were investigated. Bi2O3/CuO decreased both coercive field and remnant polarization, which was caused by an increase of the degree of diffuseness in relaxor ferroelectric materials. Electric field induced strain behavior was also investigated and it was found that the addition of Bi2O3/CuO increased the maximum induced strain and maximized electrostrictive effect. Therefore, Bi2O3/CuO was useful as a sintering aid, which improved the dielectric and the relaxor ferroelectric properties as well as the electric field induced strain of PLZT ceramics. 相似文献
9.
Low sintering temperature ZnNb2O6 microwave ceramics were prepared by doping with mixed oxides of V2O5–Bi2O3 and V2O5–Bi2O3–CuO. The effects of additives on the microstructure and dielectric properties of the ceramics were investigated. The results show that doping with V2O5–Bi2O3 can reduce the sintering temperature of ZnNb2O6 from 1150 °C to 1000 °C due to the formation of V2O5 and Bi2O3 based eutectic phases. The combined influence of V2O5 and Bi2O3 resulted in rod-like grains. Co-doping CuO with 1 wt.% V2O5–1 wt.% Bi2O3 further lowered the sintering temperature to 880 °C, because eutectic phases could be formed between the CuO, V2O5 and Bi2O3. A second phase of (Cu2Zn)Nb2O8 also forms when the content of CuO is greater than 2.5 wt.%. A pure ZnNb2O6 phase can be obtained when the amount of CuO was 1.0–2.5 wt.%. The Q × f values of ZnNb2O6 ceramics doped with V2O5–Bi2O3–CuO were all higher than 25,000 GHz. The dielectric constants were 22.8–23.8 at microwave frequencies. In addition, theτf values decreased towards negative as the content of CuO increased. The ceramic with composition of ZnNb2O6 + 1 wt.%V2O5 + 1 wt.% Bi2O3 + 2.5 wt.% CuO sintered at 880 °C exhibited the optimum microwave dielectric properties, is 23.4, Q × f is 46,975 GHz, and τf is −44.89 ppm/°C, which makes it a promising material for low-temperature co-fired ceramics (LTCCs). 相似文献
10.
《Ceramics International》2022,48(7):9362-9370
Ultrafine-grained O′-Sialon-based ceramics were prepared by two-stage sintering at 1250 °C, with large particle GH4169 superalloy powder and nano Al2O3–Y2O3 as composite sintering aids. The effects of these aids on the densification, microstructure, and mechanical properties of O′-Sialon-based ceramics during two-stage sintering were also studied. Studies have shown that the densification process of O′-Sialon-based ceramics promoted by composite sintering additives, presents with the characteristics of two-stage liquid-phase sintering. In the first stage, GH4169 formed ultrafine-grained sintered clusters in the sintered material through liquid phase diffusion. In the second stage, the uniformly dispersed nano Al2O3–Y2O3 realized the uniform sintering of the material. In the fracture process, the ultrafine-grained sintered clusters hindered the crack propagation and promoted multiple deflections of the crack around the edge of the clusters, achieving the effect of crack deflection toughening. This effect, dominated by ultrafine-grained sintered clusters, significantly improved the fracture toughness of O′-Sialon-based ceramics up to 8.52 MPa m1/2. 相似文献
11.
《Ceramics International》2023,49(12):20429-20436
In solar thermal technology, solar receiver materials with high solar absorptivity and photocatalytic efficiency have recently become a mandatory requirement for promoting and maximizing the released thermal and electrical energy. This paper presents a detailed study of the optical performance and thermal stress durability of the promising solar receiver material, black Al2O3/CuO ceramics. Different Al2O3/CuO ceramics with different CuO content (10–40 wt%) were obtained by the pressureless sintering method. Optical properties such as solar absorbance and reflectance, band gap energy and photoluminescence are inclusively investigated. The thermal stress resistance of the obtained ceramic receivers is simulated using the finite element modeling (FEM) method at different temperatures. Results indicated that adding and increasing the content of CuO to Al2O3 has a significant role in transforming alumina from a non-solar light-absorbed material to a solar absorber material with high absorptivity in the Ultraviolet–Visible-Near Infrared (UV-VIS-NIR) spectrum. Composite with 40 wt% CuO has recorded the maximum absorbance of 75% in the visible light region. Moreover, Al2O3/CuO ceramics gave multiple graded band-gaps in the range of (1.6–5 eV). Composites with high wt% of CuO have the most increased photocatalytic activity and light emissivity efficiency. Thermal stress analysis of the different ceramics showed outstanding stress durability with uniform heat distribution. Hence, black Al2O3/CuO ceramics can be considered ideal solar absorber materials with high sustainability and durability at high temperatures. 相似文献
12.
《Ceramics International》2023,49(15):24960-24971
Stereolithography based 3D printing provides an efficient pathway to fabricate alumina ceramics, and the exploration on the mechanical properties of 3D printed alumina ceramics is crucial to the development of 3D printing ceramic technology. However, alumina ceramics are difficult to sinter due to their high melting point. In this work, alumina ceramics were prepared via stereolithography based 3D printing technology, and the improvement in the mechanical properties was investigated based on the content, the type and the particle size of sintering aids (TiO2, CaCO3, and MgO). The flexural strength of the sintered ceramics increased greatly (from 139.2 MPa to 216.7 MPa) with the increase in TiO2 content (from 0.5 wt% to 1.5 wt%), while significant anisotropy in mechanical properties (216.7 MPa in X-Z plane and 121.0 MPa in X–Y plane) was observed for the ceramics with the addition of 1.5 wt TiO2. The shrinkage and flexural strength of the ceramics decreased with the increase in CaCO3 content due to the formation of elongated grains, which led to the formation of large-sized residual pores in the ceramics. The addition of MgO help decrease the anisotropic differences in shrinkage and flexural strength of the sintered ceramics due to the formation of regularly shaped grains. This work provides guidance on the adjustment in flexural strength, shrinkage, and anisotropic behavior of 3D printed alumina ceramics, and provides new methods for the fabrication of 3D printed alumina ceramics with superior mechanical properties. 相似文献
13.
Wenke Liang Bin Meng Qingfei Xiao Xinyu Ping Qian Zheng Chen Li Zhidong Xia 《International Journal of Applied Ceramic Technology》2021,18(4):1153-1163
A second phase of Y2O3-stabilized Bi2O3 (Bi0.75Y0.25O1.5,YSB) is introduced into Y2O3-doped CeO2 (Ce0.8Y0.2O1.9,YDC) as a sintering additive and the composite ceramics of YDC-xYSB (x = 0, 5, 10, 20, 30, 40 wt%) are prepared through sintering at 1100°C for 6 h in air atmosphere. The YDC-xYSB ceramics are composed of both YDC and YSB with cubic fluorite structure, and no other impurity phases are detected in XRD patterns. The relative density of YDC-xYSB rises firstly for x ≤5 wt%, and then it declines with YSB addition from 5 to 40 wt%. The average grain size of YDC decreases from 270 nm to 85.7 nm with YSB addition from 0 to 40 wt%. The YSB phase segregates at the grain boundaries of YDC based on the TEM analysis result. The ionic conductivity of YDC-xYSB (x ≥5 wt%) is lower than that of YDC in the test temperature of 200°C–500°C, while it gradually exceeds that of YDC in 500°C–750°C. At 750°C, the conductivity of YDC-30%YSB (6.22 × 10−2 S/cm) is 1.35 times higher than that of YDC (4.6 × 10−2 S/cm). The YSB addition can improve the ionic conductivity of YDC in 500°C–750°C and decrease its sintering temperature. 相似文献
14.
《Ceramics International》2023,49(7):10238-10248
High-strength ceramics were prepared from high alumina fly ash (HAFA) and activated alumina as raw materials with magnesia as a sintering additive. The growth kinetics and influence mechanism of secondary mullite whiskers were investigated. Meanwhile, the effects of the Al2O3/SiO2 mass ratio (A/S) and the amount of magnesia on the content and morphology of mullite in the green body were investigated, so as to emphasize the effect of the liquid phase in the sintering process on the growth of secondary mullite whiskers. The results showed that the aspect ratio of secondary mullite whiskers increased significantly after adding activated alumina to increase the A/S ratio of raw materials. When 30 wt% activated alumina was added, the mullite content increased by 5.39%, and the whisker length increased from 1.36 μm to 4.18 μm. The addition of magnesia improved the liquid phase formed during the sintering process and the K value method was used to determine the sintering liquid phase content under various conditions. It was observed that increasing the magnesia level by 1 wt% could raise the liquid phase content by 5–7%. When the total liquid content of the system was 30–40%, the growth activation energy in the diameter direction of the whisker reduced significantly, promoting the growth of secondary mullite whiskers along the C axis. The morphology of mullite gradually developed from fibrous to long columnar crystal, making it combine more densely with the green body matrix. Furthermore, the staggered long columnar mullite crystal structure changes the fracture mode of ceramics from intergranular to transgranular fracture, which fully uses the high mechanical strength of mullite. As a result, the fracture energy and strength of ceramics are significantly improved. 相似文献
15.
《Ceramics International》2016,42(16):18333-18337
The effect of CuO/MnO additives on phase composition, microstructures, sintering behavior, and microwave dielectric properties of 3ZrO2-3TiO2-ZnNb2O6 (3Z-3T-ZN) ceramics prepared by conventional solid-state route were systematically investigated. CuO/MnO doped ceramics exhibited a main phase of α-PbO2-structured ZrTi2O6 and a secondary phase of rutile TiO2. SEM results showed that the grain size of MnO doped ceramics became larger with increasing amount of dopants. The presence of CuO/MnO additives effectively reduced the sintering temperature of 3Z-3T-ZN ceramics to 1220 °C. MnO doped into ceramics could enhance the Q×f values significantly. The 0.5 wt% CuO doped 3Z-3T-ZN ceramics with 0.5 wt% of MnO, sintered at 1220 °C for 4 h, was measured to show superior microwave dielectric properties, with an εr of 41.02, a Q×f value of 44,230 GHz (at 5.2 GHz), and τf value of +2.32 ppm/°C. 相似文献
16.
Partha Haldar Tapas Kumar Bhattacharya Nipu Modak 《International Journal of Applied Ceramic Technology》2021,18(1):110-118
Sintering of alumina from 1500°C to 1650°C and tribo-mechanical properties at room temperature had been investigated using nano CuO as a sintering aid. Bulk density gradually increases with sintering temperature from 1500°C to 1600°C and is optimized at 1600°C, beyond this, bulk density does not significantly increase at 1650°C. The addition of 2 wt% CuO showed the best result on densification. Densification of about 97.74% was attained at 1600°C with the incorporation of 2 wt% CuO. Nano CuO at grain boundaries forms CuAl2O4 liquid which modifies the morphology of the grain and improves mechanical properties. The formation of self-lubricating tribo-film on the wear track results in a low coefficient of friction <0.2 and reduces specific wear rate. 4 wt% CuO addition increases contact tensile stress (σmax) by 51.2% and high Hertzian contact pressure (Pmax≈1.51 GPa) causes plastic deformation of wear track. The re-solidified strengthening bond phase on the wear track simultaneously increases in friction coefficient and wear resistance with CuO addition. The optimizing effect of CuO addition shows that 2 wt% significantly decreases wear rate, and increases hardness and fracture toughness. 相似文献
17.
Hai Tao Jiang Ji Wei Zhai Jing Ji Zhang Xi Yao 《International Journal of Applied Ceramic Technology》2013,10(5):873-878
The sintering behaviors and dielectric properties of Ba0.6Sr0.4TiO3 ceramics were investigated as a function of B2O3 and CuO content. The addition of both B2O3 and CuO reduced the sintering temperature of Ba0.6Sr0.4TiO3 about 500°C. It was suggested that a liquid phase BaCu(B2O5) was formed and assisted the densification of Ba0.6Sr0.4TiO3 ceramics. Ba0.6Sr0.4TiO3 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. 相似文献
18.
Large recoverable energy storage density and low sintering temperature in potassium‐sodium niobate‐based ceramics for multilayer pulsed power capacitors
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Bingyue Qu Hongliang Du Zetian Yang Qinghui Liu 《Journal of the American Ceramic Society》2017,100(4):1517-1526
Multilayer pulsed power ceramic capacitors require that dielectric ceramics possess not only large recoverable energy storage density (Wrec) but also low sintering temperature (<950°C) for using the inexpensive metals as the electrodes. However, lead‐free bulk ceramics usually show low Wrec (<2 J/cm3) and high sintering temperature (>1150°C), limiting their applications in multilayer pulsed power ceramic capacitors. In this work, large Wrec (~4.02 J/cm3 at 400 kV/cm) and low sintering temperature (940°C) are simultaneously achieved in 0.9(K0.5Na0.5)NbO3–0.1Bi(Mg2/3Nb1/3)O3–1.0 mol% CuO ceramics prepared using transition liquid phase sintering. Wrec of 4.02 J/cm3 is 2‐3 times as large as the reported value of other (Bi0.5Na0.5)TiO3 and BaTiO3‐based lead‐free bulk ceramics. The results reveal that 0.9(K0.5Na0.5)NbO3–0.1Bi(Mg2/3Nb1/3)O3–1.0 mol% CuO ceramics are promising candidates for fabricating multilayer pulsed power ceramic capacitors. 相似文献
19.
Han Luo Yuanbing Li Ruofei Xiang Wenbao Jia Minghui Li Shujing Li Dong Lao Hailu Wang Qingfeng Yan Cheng Dong 《Ceramics International》2021,47(11):15508-15519
The efficient optimisation of radiation shielding materials (RSMs), which protect people from potential radiant threats, is highly desirable; however, it remains challenging. This study addresses the low-cost fabrication of the ceramic-based RSMs, aluminium borate-based ceramics using Bi2O3 as a novel simultaneous shielding agent and sintering promoter. The phase compositions, microstructures, sintering kinetics, and performances of the as-prepared Bi2O3 doped aluminium borate ceramics (BDABCs) are systematically researched. Finally, co-shielding tests for neutron and gamma radiation are performed. The results demonstrate that Bi2O3 can positively influence the sintering densification process of BDABCs via the evident reduction in the sintering activation energy. The migration of the Bi2O3–B2O3 liquid phase affects the pore structure, crystal morphology, and thermal conductivity of the samples. The obtained BDABCs exhibited highly reliable mechanical properties with a maximum elastic modulus and modulus of rupture of 124.3 GPa and 54.9 MPa, respectively; controllable thermal conductivity from 1.32 to 6.16 W m?1 K?1; and 12 wt% Bi2O3-doped sample (1400 °C × 3 h, 1.5 cm) shows the best radiation shielding performance, including 58.6% neutron and 26.6% γ rays. The obtained results manifest the enormous potential of BDABCs as structural materials and functional RSMs. 相似文献
20.
Development of a lead‐free copper co‐fired BNT‐based piezoceramic sintered at low temperature
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Compatibility of Bi‐based piezoelectric ceramic and copper electrodes is demonstrated by co‐firing 0.88Bi1/2Na1/2TiO3–0.08Bi1/2K1/2TiO3–0.04BaTiO3 (BNKBT88) with copper. A combination of Bi2O3, CuO, ZnO, Li2CO3, and B2O3 are used as additives to reduce firing temperature to 900°C with minimal effect on the electromechanical properties compared to sintering at 1150°C without additives. Co‐firing with copper electrodes requires controlled oxygen sintering at low temperature. The atmosphere is controlled using carbon dioxide and hydrogen gas to maintain an oxygen partial pressure of 6.1 × 10?8 atm, which is necessary for the coexistence of Cu metal and Bi2O3. The thermodynamic activity of bismuth oxide in BNKBT88 is calculated to be 0.38. BNKBT88 ceramics were successfully co‐fired with internal as well as surface Cu metal electrodes. The copper co‐fired ceramics were successfully polarized and the dielectric and piezoelectric properties are evaluated. 相似文献