B2O3 Sintering Research Articles

Effect of Sr2+doping on the microwave dielectric properties of BaZrO3 ceramics

ABSTRACT In this study, undoped and Sr2+ doped BaZrO3 ceramics were prepared by solid-state reaction using 3 wt-% B2O3 as sintering aid. The phase composition and microstructure of BaZrO3 were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that introducing an appropriate amount of Sr2+ makes BaZrO3 ceramics Q × f value and density increase. In addition, the dielectric constant of BaZrO3 ceramics increases with the increase of Sr2+ addition. With excellent microwave dielectric properties, ϵ r = 34.17 and Q × f value of 39,070 GHz(@ 7.8 GHz) τf = + 140 ppm/°C were obtained in 6 at.-% Sr2+ doped BaZrO3 with 3 wt-% B2O3 sintering aid at 1275°C for 5 h. Using this material as the medium, the simulation of GPS antenna by HFSS software shows that this material has the potential to be used as the antenna medium material.

B2O3 as an effective sintering aid in enhancing the lithium-ion conductivity of LiTa2PO8 solid electrolyte

LiTa2PO8 (LTPO) is a newly developed oxide-type solid electrolyte. It is found to exhibit good ionic conductivity (>10−4 S/cm) at room temperature, making it suitable for application in all-solid-state Li-ion batteries. However, there are not many studies conducted on this material. In this study, we investigate the effects of B2O3 sintering aid on the various properties of LTPO synthesized via the solid-state reaction method. The samples containing three different concentrations of B2O3 (0.5, 1, and 1.5 wt%) are synthesized at various sintering temperatures ranging from 850 °C to 1050 °C. The various sample properties are characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and impedance spectroscopy techniques. The highest total ionic conductivity among all the samples is found to be 3.55 x 10−4 S/cm for LTPO containing 1 wt% B2O3 sintered at 950 °C. This ionic conductivity value is around 3.5 times higher than that of pure LTPO and is obtained at a relatively lower sintering temperature compared to pristine LTPO.

Optimization of Zn2GeO4 microwave dielectric ceramics via Cu substitution and B2O3 sintering aid for LTCC application

Optimization of Zn2GeO4 microwave dielectric ceramics via Cu substitution and B2O3 sintering aid for LTCC application

Effect of B2o3 Sintering Aid on the Structural, Morphological, and Electrical Properties of Lita2po8 Solid Electrolyte

Effect of B2o3 Sintering Aid on the Structural, Morphological, and Electrical Properties of Lita2po8 Solid Electrolyte

Reducing the sintering temperature of (In0.5Nb0.5)0.05Ti0.95O2 ceramics by adding B2O3 sintering aid

TiO2 ceramics co-doped with In and Nb exhibit unusual large dielectric-permittivity phenomena, but their sintering temperature is essentially higher than 1400 °C and the holding time is usually longer than 5 h, which is very uneconomical for industrial production and practical applications. Therefore, to maintain the relatively good dielectric properties of In and Nb co-doped TiO2 ceramics and reduce the sintering temperature to about 1300 °C, B2O3, was added as a sintering aid to prepare B2O3/(In0.5Nb0.5)0.05Ti0.95O2 ceramics in this paper. The crystalline structures, microstructures, and electrical properties were investigated and discussed. The results showed that the sintering temperature of B2O3/(In0.5Nb0.5)0.05Ti0.95O2 ceramics indeed prominently decreased, but their dielectric loss was relatively large, possibly caused by the pores left following B2O3 volatilization.

Structure and microwave dielectric properties of BaAl2Si2O8 ceramic with Li2O–B2O3 sintering additive

The BaAl2Si2O8 ceramics with x wt% Li2O–B2O3 sintering additive (x = 0, 1, 3, 5 and 7, respectively) were prepared by the solid-state reaction method. The sintering temperature, structure and microwave dielectric properties of the prepared samples were investigated. The results show that the sintering temperature of BaAl2Si2O8 ceramic can be significantly reduced from 1400 °C to below 950 °C when x ≥ 5. All of the hexacelsian transformed into celsian and no second phase was observed when 1 ≤ x ≤ 7. Moreover, the addition of Li2O–B2O3 can decrease the porosity and improve the microstructure of BaAl2Si2O8 ceramic. The BaAl2Si2O8 ceramic with 5 wt% Li2O–B2O3 sintering additive sintered at 950 °C for 3 h shows the good microwave dielectric properties of εr = 6.34, Q × f = 24366 GHz, and τf = −27.42 ppm/°C.

Characterizations of low-temperature sintered BaCo1.3Ti1.3Fe9.4O19 M-type ferrite for high-frequency antenna application

BaCo1.3Ti1.3Fe9.4O19 ferrite was synthesized by solid-state reaction route. Co and Ti ions were substituted for Fe cation to modify the anisotropy field of the ferrite. The effects of B2O3 and CuO sintering additives on the phase stability, sintering behavior at 900 °C, microstructure development, magnetic and dielectric properties of the ferrite were investigated. The densification of the ferrite at 900 °C was found to increase upon B2O3 and CuO addition. A permittivity of 19 and initial permeability of 11 was obtained in the ferrite containing 5 wt% B2O3 sintering additive. There was a nominal decrease in saturation magnetization of the ferrite with increasing sintering additive. An antenna based on the low temperature sintered ferrite substrate was designed. Antenna parameters such as resonance frequency, return loss, voltage standing wave ratio (VSWR), and bandwidth were simulated and reported. The antenna miniaturization factor (n) was calculated and found n = 11 for the sample with 5 wt% B2O3. The sample containing 3 wt% B2O3 plus 2 wt% CuO showed an impedance of about Zi = 1.

The effects of B2O3 on the microstructure and properties of lithium aluminosilicate glass-ceramics for LTCC applications

Lithium aluminosilicate glass-ceramics were prepared using melt-quenching method. B2O3 was added into glass-ceramics as sintering aids. The effects of B2O3 addition and sintering temperature on the microstructure, phase composition, dielectric properties, thermal and mechanical properties and densification of glass-ceramics were investigated. The addition of B2O3 lowered the sintering temperature of the glass-ceramics from 950 to 800 °C, and improved the bending strength from 97 to 195 MPa. The coefficient of thermal expansion of materials increased with the increasing sintering temperature and B2O3 content. The results show that B2O3 is helpful to densification sintering of glass-ceramics. The samples with 3 wt% B2O3 sintered at 800 °C showed εr of 7.2, tanδ of 1.4 × 10−3, bending strength of 195 MPa, and CTE of 2.67 × 10−6 K−1. The results indicated that the LAS glass-ceramic can be a possible candidate for LTCC substrate applications.

Structure, Microwave Dielectric Properties, and Novel Low‐Temperature Sintering of xSrTiO3–(1−x)LaAlO3 Ceramics with LTCC Application

xSrTiO3–(1−x)LaAlO3 ceramics with ZnO–B2O3 sintering aid were prepared by solid‐state reaction method leading to a significant decrease in sintering temperature from 1550°C to 1050°C. The structure, microwave dielectric properties, and low‐temperature sintering behavior were systematically investigated. The results revealed the relationships among ionic size, ionic polarizability and cell volume. With increasing additive, chemical ordering of B‐site cations was indicated with selected area electron diffraction (SAED) patterns, HRTEM images and Raman spectrum, which contributed to the greatly enhanced microwave dielectric properties. Particularly, the 0.7Sr0.85 Mg0.15TiO3–0.3LaAlO3 ceramics modified with 10 wt % ZnO‐B2O3 can further decrease the sintering temperature down to 950°C without deteriorating its performance. Thermal tests implied ceramics featured good chemical compatibility with Cu/Ag electrode. Thus, they can be cofired with internal Cu/Ag electrodes in special patterns to fulfill different electrical functions for LTCC (low‐temperature cofired ceramic) application.

Microwave dielectric properties of B2O3-added Li2MgTiO4 ceramics for LTCC applications

ABSTRACTLi2MgTiO4 (LMT) ceramics which are synthesized using a conventional solid-state reaction route. The LMT ceramic sintered at 1250°C for 4 h had good microwave dielectric properties. However, this sintering temperature is too high to meet the requirement of low-temperature co-fired ceramics (LTCC). In this study, the effects of B2O3 additives and sintering temperature on the microstructure and microwave dielectric properties of LMT ceramics were investigated. The B2O3 additive forms a liquid phase during sintering, which decreases the sintering temperature from 1250°C to 925°C. The LMT ceramic with 8 wt% B2O3 sintered at 925°C for 4 h was found to exhibit optimum microwave dielectric properties: dielectric constant 15.16, quality factor 64,164 GHz, and temperature coefficient of resonant frequency -28.07 ppm/°C. Moreover, co-firing of the LMT ceramic with 8 wt% B2O3 and 20 wt% Ag powder demonstrated good chemical compatibility. Therefore, the LMT ceramics with 8 wt% B2O3 sintered at 925°C for 4 h is suitable for LTCC applications.

Effects of glass additions on high pyroelectric response of low-temperature sintered Pb0.87Ba0.1La0.02(Zr0.7Sn0.24Ti0.06)O3 antiferroelectric ceramics

To find a solution to the problem that antiferroelectric materials could not be used in thick-film based uncooled infrared detectors because of their high sintering temperature, Pb0.87Ba0.1La0.02(Zr0.7Sn0.24Ti0.06)O3+6wt%PbO antiferroelectric ceramics were first prepared at 1000°C by using 0.8PbO–0.2B2O3 glass as a sintering aid. The results showed that the addition of 0.8PbO–0.2B2O3 sintering aids was beneficial for reducing the sintering temperature without deteriorating the electric properties when the content of glass was practical. The ceramics containing 1wt% 0.8PbO–0.2B2O3 sintering aids demonstrated optimal electrical field induced pyroelectric properties. The largest pyroelectric coefficient of 6100μC/m2K and figure of merit of 17×10−5Pa−0.5 were obtained in Pb0.87Ba0.1La0.02(Zr0.7Sn0.24Ti0.06)O3+6wt%PbO antiferroelectric ceramics with 1wt% glass doping, which can be comparable to that of conventional phase transition materials at a high temperature sintering. The large pyroelectric coefficient and figure of merit of low temperature sintered antiferroelectric ceramics provide a basis for antiferroelectric materials used in thick-film based infrared detectors.

A Study of Low-Temperature Sintering of (Ba0.6Sr0.4)(Ti0.94Cu0.06)O3 Ceramics with B2O3 Addition

The low-temperature sintering of (Ba0.6Sr0.4)(Ti0.94Cu0.06)O3 (BSTC) ceramics was investigated by conventional ceramics processing using a B2O3 sintering aid, and the dielectric properties and microstructures of the ceramics were examined. BSTC powders without B2O3 could not be fully densified at sintering temperatures lower than 1150°C. However, the addition of B2O3 markedly enhanced the sinterbility of BSTC powders, and the sintering temperature decreased from 1150 to 980°C. This may be due to the promotion of liquid-phase sintering. The 3 at.% B2O3-doped BSTC ceramics sintered at 980°C for 2 h exhibited a high density of 5.48 g/cm3. Transmission electron microscopy examination indicated that there are two kinds of secondary phases produced in BSTC ceramics during B2O3 addition; one is BaTi(BO3)2 with rhombohedral structure, and the other is Ba4Ti12O27 with monoclinic structure. The BSTC ceramics with 3 at.% B2O3 sintered at 980°C in air for 2 h exhibited a maximum permittivity, ϵ max = 1216, and a bulk density > 96% of theoretical density.

Efeito da adição de óxido de zinco e de óxido de boro nas propriedades do zirconato de bário dopado com ítrio

Compostos condutores protônicos de BaZr0,8Y0,2O3-δ, preparados por síntese de estado sólido, foram compactados e sinterizados com ZnO e B2O3 como aditivos. Os corpos cerâmicos sinterizados foram analisados por difração de raios X e espectroscopia de impedância. Superfícies polidas e atacadas termicamente foram observadas em microscópio de varredura por sonda. As medidas de densidade mostraram que a maior densificação foi obtida com óxido de zinco nas proporções de 2 e 5 peso%, atingindo aproximadamente 95% da densidade teórica. As medidas de resistividade elétrica evidenciaram a menor resistividade elétrica do composto cerâmico BaZr0,8Y0,2O3-δ com 5 peso% de ZnO. Os aditivos de sinterização, óxido de boro e óxido de zinco, foram eficientes para obter compostos com menores valores de resistividade elétrica que os obtidos em compostos sinterizados sem aditivos.

Microwave dielectric properties and low-temperature sintering of (Zn0.8Mg0.2)2SiO4–TiO2 ceramics with Li2O–B2O3

Effects of Li2O–B2O3 on the sintering behavior and the microwave dielectric properties of (Zn0.8Mg0.2)2SiO4–TiO2 ceramics were investigated as a function of Li2O–B2O3 content and sintering temperature. The Li2O–B2O3 combined additives successfully reduced the sintering temperature of (Zn0.8Mg0.2)2SiO4–TiO2 ceramics from 1,250 °C to 900 °C. With the increase of Li2O–B2O3 content, the TiO2 phase decreased and the unknown second phase increased, which led to the dielectric constant (e r ) and the maximum Q × f value decrease, and the temperature coefficient of resonant frequency (τ f ) shift to a negative value. The specimens with 3 wt%Li2O–B2O3 sintered at 900 °C for 2 h showed e r of 8.84, Q × f value of 15,500 GHz, and τ f of 17.8 ppm/°C. And the material was compatible with Ag electrodes, which made it a promising ceramic for low temperature co-fired ceramics technology application.