The family of oxide glasses is very wide and it is continuously developing. The rapid development of advanced and innovative glasses is under progress. Oxide glasses have a variety of applications in articles for daily use as well as in advanced technological fields such as X-ray protection, fibre glasses, optical instruments and lab glassware. Oxide glasses basically consist of network formers, such as borate, silicate, phosphate, borosilicate, borophosphate, and network modifiers such as alkali, alkaline earth and transition metals. In the present review article, Raman spectroscopy results for the structures of borate, silicate, phosphate, borosilicate, borophosphate, aluminosilicate, phosphosilicate, alumino-borosilicate and tellurite glasses are summarized.

A review of the structures of oxide glasses by Raman spectroscopy

Thermal transport in polymeric materials and across composite interfaces

Li2ATi3O8 (A=Mg, Zn) ceramics are prepared by the conventional solid-state ceramic route, and the phase purity, microstructure, and microwave dielectric properties are investigated. Li2MgTi3O8 ceramics show ɛr=27.20, Qu×f=42 000 GHz, and τf=(+) 3.2 ppm/°C, and Li2ZnTi3O8 ceramics have ɛr=25.6, Qu×f=72 000 GHz, and τf=(−) 11.2 ppm/°C, respectively, when sintered at 1075°C/4 h.

Synthesis and Microwave Dielectric Properties of Novel Temperature Stable High Q, Li2ATi3O8 (A=Mg, Zn) Ceramics

Investigation of bismuth borate glass system modified with barium for structural and gamma-ray shielding properties.

Composite technology, where a novel artificial material is fabricated by combining, for example, ceramic and polymer materials in an ordered manner or just by mixing, was earlier used widely for sonar, medical diagnostics, and NDT purposes. However, in recent decades, large numbers of ceramic–polymer composites have been introduced for telecommunication and microelectronic applications. For these purposes, composites of 0–3 connectivity (a three-dimensionally connected polymer phase is loaded with isolated ceramic particles) are the most attractive from the application point of view. Composites of 0–3 connectivity enable flexible forms and very different shapes with very inexpensive fabrication methods including simply mixing and molding. In this brief review, we gather together the research carried out within 0–3 ceramic–polymer composites for microwave substrates, also including embedded capacitor, inductor, or microwave-absorbing performances.

Polymer–Ceramic Composites of 0–3 Connectivity for Circuits in Electronics: A Review

Development of a low-temperature sintered dielectric material derived from Li2MgSiO4 (LMS) for low-temperature cofired ceramic (LTCC) application is discussed in this paper. The LMS ceramics were prepared by the solid-state ceramic route. The calcination and sintering temperatures of LMS were optimized at 850°C/4 h and 1250°C/2 h, respectively, for the best density and dielectric properties. The crystal structure and microstructure of the ceramic were studied by the X-ray diffraction and scanning electron microscopic methods. The microwave dielectric properties of the ceramic were measured by the cavity perturbation method. The LMS sintered at 1250°C/2 h had ɛr=5.1 and tan δ=5.2 × 10−4 at 8 GHz. The sintering temperature of LMS is lowered from 1250°C/2 h to 850°C/2 h by the addition of both lithium borosilicate (LBS) and lithium magnesium zinc borosilicate (LMZBS) glasses. LMS mixed with 1 wt% LBS sintered at 925°C/2 h had ɛr=5.5 and tan δ=7 × 10−5 at 8 GHz. Two weight percent LMZBS mixed with LMS sintered at 875°C/2 h had ɛr=5.9 and tan δ=6.7 × 10−5 at 8 GHz.

Low‐Temperature Sintering and Microwave Dielectric Properties of Li2MgSiO4 Ceramics

Cerium oxide (CeO2) filled polytetrafluoroethylene (PTFE) composites prepared by powder processing technique for microwave substrate application is presented in this paper. The PTFE is used as the matrix and the dispersion of CeO2 in the composite is varied up to 0.6 by volume fraction, and the dielectric properties were studied at 1 MHz and microwave frequencies. The relative permittivity and dielectric loss increased with increase in CeO2 content. For 0.6 volume fraction loading of the ceramic, the composite has ɛr of 5 and tan δ of 0.0064 at 7 GHz. Different theoretical approaches have been employed to predict the effective permittivity of composite systems and the results were compared with that of experimental data. The serial mixing model shows good correlation with the experimental results.

https://ceramics.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1744-7402.2008.02228.x

Low Dielectric Loss PTFE/CeO2 Ceramic Composites for Microwave Substrate Applications

The effect of glass additives on the microstructure, densification, and microwave dielectric properties of cerium oxide for low-temperature co-fired applications was investigated. Different weight percentages of quenched glass such as B2O3, B2O3–SiO2, Al2O3–SiO2, ZnO–B2O3, BaO–B2O3–SiO2, MgO–B2O3–SiO2, PbO–B2O3–SiO2, ZnO–B2O3–SiO2, 2MgO–Al2O3–5SiO2, LiO–B2O3–SiO2, Bi2O3–ZnO–B2O3–SiO2, and LiO–MgO–ZnO–B2O3–SiO2 were added to CeO2 powder. The crystal structure of the ceramic–glass composites was studied by X-ray diffraction, microstructure by scanning electron microscopy, and phase composition using the energy-dispersive X-ray analysis technique. The microwave dielectric properties such as relative permittivity (ɛr), quality factor (Quxf), and coefficient of temperature variation of resonant frequency (τf) of the ceramics have been measured in the frequency range 4–6 GHz. Addition of B2O3 and Bi2O3–ZnO–B2O3–SiO2 lowered the sintering temperature of ceria to about 900°C. The 20 wt% B2O3 and 10 wt% Bi2O3–ZnO–B2O3–SiO2-added CeO2 and sintered at 900° and 950°C showed: Quxf=24 200 and 12 000 GHz, ɛr= 13.2 and 22.4, and τf=−46 and –57.2 ppm/°C, respectively.

https://ceramics.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1551-2916.2008.02756.x

Microwave Dielectric Properties and Low-Temperature Sintering of Cerium Oxide for LTCC Applications

Cadmium selenide (CdSe) thin films of high crystalline quality on glass substrate have been prepared by chemical bath deposition technique from an aqueous bath containing tetramine cadmium and sodium selenosulphate. Structural analysis using XRD shows that the film is single phase, crystallized in hexagonal structure with preferred growth in (111) direction. The energy band gap calculated from the absorption spectra of unannealed CdSe thin films shows an optical band gap of 1.8 eV and absorption coefficient near band edge (α)—0.58 × 105 cm−1. The conductivity of CdSe thin films is n-type.

Chemical bath deposition and characterization of CdSe thin films for optoelectronic applications

The ATiO 3 (A= Co, Mn, Ni) dielectric ceramics have been synthesized by the conventional solid-state ceramic route. The structure and microstructure of these ceramic samples have been studied using powder X-ray diffraction and scanning electron microscopy. The microwave dielectric properties such as relative permittivity (e r ), quality factor (Q u ×f), and coefficient of temperature variation of resonant frequency (τ f ) of the ceramics have been measured in the frequency range 4-6 GHz using resonance methods. The dielectric constant of ATiO 3 (A = Co, Mn, Ni) varies from 19 to 25 and if close to 50 ppm/°C. The ceramics have high-quality factors (Q u †f) of 62500 GHz (at 5.42 GHz) for CoTiO 3 , 15200 GHz (at 5.22 GHz) for MnTiO 3 , and 13900 GHz (at 5.24 GHz) for NiTiO 3 , respectively.

P. S. Anjana

Papers

Low‐Temperature Sintering and Microwave Dielectric Properties of Li2MgSiO4 Ceramics

Low Dielectric Loss PTFE/CeO2 Ceramic Composites for Microwave Substrate Applications

Microwave Dielectric Properties and Low-Temperature Sintering of Cerium Oxide for LTCC Applications

Chemical bath deposition and characterization of CdSe thin films for optoelectronic applications

Synthesis, characterization, and microwave dielectric properties of ATiO3 (A = Co, Mn, Ni) ceramics