Ceramic Technology Research Articles

Effect of Bismuth Oxide on the Structure, Electrical Resistance and Magnetization of Lithium Zinc Ferrite

The structural, electrical, and magnetic properties of lithium zinc ferrite prepared by ceramic technology have been studied. The composition of lithium zinc ferrite is Li0.4Fe2.4Zn0.2O4 with 1 and 2 wt % bismuth oxide. The addition of Bi2O3 prior to sintering of the samples has been shown to affect the structural, electrical, and magnetic properties of the ferrite. A significant increase in density from 4.47 to 4.65 g/cm3 and a decrease in porosity from 4.8 to 2.3% have been observed when the concentration of bismuth oxide has been increased to 2 wt %. The Bi2O3-containing samples have higher specific electrical resistivity compared to that of the additive-free lithium zinc ferrite. The introduction of bismuth oxide has reduced the specific saturation magnetization from 70.55 to 54.76 G cm3/g. The Curie temperature has not changed significantly. An optimal combination of macroscopic properties of ferrite has been found at 1 wt % Bi2O3 concentration.

Magnetic Properties of a Nickel–Zinc Ferrite Powder with Different Degrees of Dispersion

The influence of the degree of dispersion of a nickel–zinc ferrite powder of a Ni0.7Zn0.3Fe2O4 composition on its magnetic properties has been considered. The material has been synthesized using the ceramic technology with preliminary mechanical activation of precursors. The degree of dispersion has been varied using different modes of its dry grinding in a ball mill. The patterns of the changes in saturation magnetization and the coercive force as a function of grinding modes and a specific surface area of the ferrite powder have been established. The changes in the pattern of the magnetic phase transition in the region of the Curie temperature of materials with different degrees of dispersion have been determined.

Enhancing the Performance of Oxide‐Based Transverse Thermoelectric Generators by Optimized Internal Geometry

AbstractIn transverse thermoelectric generators (TTEGs), comprising an artificially anisotropic material formed by a layered and tilted structure of two materials, the induced thermoelectric voltage is generated perpendicular to the applied temperature gradient. The performance of TTEGs composed of alternate layers of La1.99Sr0.01CuO4 (LSCO) and silver (Ag), tilted at an angle φ, with metal‐to‐ceramic thickness ratio νt, is investigated. Improvement in performance is achieved by optimizing the internal geometry parameters, φ and νt of the tilted layered structure. The transverse power factor PFtr and figure‐of‐merit ZtrT of the artificially tilted material composite are analytically calculated and presented in color contours. Experimentally, a power output Pout of 14.5 mW at ΔT = 140 K is measured for a TTEG with φ = 66°, compared to 2.8 mW and 11 mW for generators with φ of 20° and 45°, respectively. Moreover, TTEGs with different values of νt are prepared. Furthermore, transverse multilayer thermoelectric generators (TMLTEG) with output power of 14.3 mW at ΔT = 225 K are fabricated utilizing the ceramic multilayer technology. It is demonstrated that the transverse thermoelectric effect using an artificial anisotropic material consisting of ceramic and metal can be explored for autonomous thermoelectric energy generation for low‐power applications.

Characterization of Ceramic Tile Bodies Prepared From Clays Collected from Four

Sierra Leone has high potentials for the setting-up of ceramic industry because of its huge virgin deposits of raw materials, chiefly clay, but lacks the technological know-how to utilize these materials to an economically sound level. Tile body offers a foundation for the performance of a glaze. The chemical and mineralogical composition of these clay bodies coupled with some physical properties, such a plasticity, bulk density, porosity, and water absorption, play significant role in determining the quality of the glazed surface.This is attested by certain glaze defects like pinholes, crazing and crawling on the glaze surface resulting mainly from bubble development within the body matrix during firing. The study aims at contributing to the promotion and use of appropriate ceramic building materials technology in Sierra Leone, by providing relevant research data to guide the production of quality ceramic products. The three key objectives, were to determine (1) the physical properties (2) chemical properties (3) mechanical properties of the clay samples investigated for their suitability in clay tile bodies production. Clay samples were collected from four sites in Sierra Leone namely Matankay (C-M) in the Western Rural District, Bo (C-B) in Bo District, Koribondo (C-K) in Pujehun District and Yele (C-Y) in Tonkolili District. Based on their plasticity index values, grain size distribution, bulk density, porosity and dry-fired shrinkage results obtained from this study, the four clay samples investigated are suitable for clay tile body production provided grog, frits, fluxes and other components are added proportionately and fired at temperatures above 1100oC to improve vitrification of the clay tile body during biscuit firing before application of the glaze.

Design of perovskite solar brick for textile ceramic technology

Textile Ceramic Technology (TCT) is an innovative industrialised façade cladding system that consist of a steel wire mesh in where ceramic pieces are inserted in. This paper presents the first steps in the design of a Solar Brick (SB) for TCT capable of producing energy. The perovskite solar thin-film emerging technology is the photovoltaic system considered for the design in this study considering its excellent electrical performances and its ability to be fabricated on flexible substrate. The present research shows the first SB prototype and the experimental tests carried out to check the performance and market viability possibilities.

Printing highly sensitive strain gauges with polymer-derived ceramics and In2O3 composites for high-temperature applications

The development of high-temperature thick film strain gauges (TFSGs) that offer both durability and a high gauge factor (GF) remains a formidable challenge. This study integrates polymer-derived ceramic technology with filler techniques to introduce the SiCNO/In2O3 TFSG. The proposed TFSG demonstrates a stable strain response and exceptional thermal stability, enabling its application at temperatures up to 1100°C. Notably, the SiCNO/In2O3 TFSG exhibits minimal resistance drift of 0.31%/h at 1100°C, and an impressive GF of 10.94 at 1000°C. These advancements underscore its significant potential for applications requiring precise strain monitoring under harsh thermal conditions, such as propulsion systems and industrial processes.

Sintering activation energy and low-temperature sinterable process of Boron-lanthanide glass/Li2Zn3Ti4O12 ceramic composite systems for LTCC technology

This work investigates the characteristics of wettability, activation energy for sintering, evolution of phase structure, and behavior during the low-temperature sintering process of B2O3-La2O3-MgO-TiO2 (BLMT) glass/Li2Zn3Ti4O12 ceramic composites for low temperature co-fried ceramics technology (LTCC). As the BLMT glass content increases from 0 to 10 wt%, the average sintering activation energy (Ea) of the composite decreases from 450 ± 8 to 356 ± 37 kJ/mol. There are two phases the primary Li2Zn3Ti4O12 phase and the secondary LaBO3 phase, the latter precipitates from the BLMT glass after sintering at 700 °C. This indicates that BLMT glass promotes the sintering of Li2Zn3Ti4O12 ceramic below 900 °C. In composites containing 20 wt% or more glass, sintering is governed by both liquid-phase sintering and reactive viscous sintering. As the BLMT glass content increases, the impact of viscous flow on the densification process becomes more pronounced. Simultaneously, when the glass content is greater than 20 wt%, the glass precipitates LaBO3, TiO2, and MgLaB5O10 phases between 700 and 750 °C. After 850 °C, the glass melts and reacts with Li2Zn3Ti4O12 phase to produce a new TiO2 phase. Accordingly, the activation energy (Ea) of sintering the composite material increases from 393 ± 17 to 667 ± 1 kJ/mol.

Influence of V substitutions on sintering behaviors and microwave dielectric properties of Ba4LiNb3O12 ceramic

AbstractIn this study, a series of Ba4Li(Nb1‐xVx)3O12 (x = 0.05∼0.3) ceramics were synthesized using the solid‐state reaction method. X‐ray powder diffraction (XRD) analysis shows that the composite ceramics contain both Ba4LiNb3O12 and Ba3(VO4)2 phases, without any other phases present. The grains consist of Ba4LiNb3O12 and Ba3(VO4)2, as illustrated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Additionally, with the increase of V content, the grain size decreases, and the (microwave dielectric constant) decreases, the (resonant frequency temperature coefficient) value decreases, and the value increases (where = quality factor = 1 / dielectric loss, and = resonant frequency). The densest Ba4Li(Nb0.7V0.3)3O12, with a of 31.3, of + 70 ppm/°C, and high of 42 850 GHz, was obtained at a sintering temperature of 1350°C. Furthermore, the addition of 5 wt.% BaCu(B2O5) (BCB) into Ba4Li(Nb0.7V0.3)3O12 resulted in obtaining dense ceramics at a sintering temperature of 925°C, with a of 23.5, a high value of 14 370 GHz, and of + 88 ppm/°C. Further investigations have shown that Ba4Li(Nb1‐xVx)3O12 ceramics are chemically compatible with Ag, suggesting its potential use in low‐temperature cofired ceramics technology.

КЕРАМИЧЕСКИЕ ИЗДЕЛИЯ ИЗ СРЕДНЕВЕКОВОГО ГОРОДИЩА ЖАЙЫК(по материалам раскопок 2015 г.)

The presented article is devoted to one of the most common artifacts of archaeological complexes – ceramics. Based on the archaeological analysis of the products, the morphology and technical characteristics of some types are briefly revealed. The research base of the article consists of materials from the archaeological excavation of the Zhaiyk settlement, carried out during the 2015 field season. Ceramic production, as one of the specialized types of craft, has a certain set of special technical means and devices. Generalization of data on technology and, above all, the design of roasting furnaces over a certain, rather long, chronological period within one region makes it possible to trace the evolution of special roasting devices. This, in turn, allows us to make a conclusion about the level of ceramic production technology in a particular period, as well as judge the degree of specialization of the craft at various stages of the development of pottery. In addition, a detailed analysis of the design of the forges makes it possible to identify mutual influences, and often direct borrowings in pottery technology. For the medieval settlements of the North-Eastern Caspian region, this is all the more relevant, since based on the analysis of the earliest structures, it is possible to resolve the issue of the time and ways of the appearance of the region and the direction of its further evolution.

High-entropy processed high quality and low-temperature cofired LiMgPO4-based dielectric ceramics for low-loss packaged millimeter-wave filters

In this work, we successfully integrated the high-entropy concept into LiMgPO4-based ceramics by strategically substituting Mg2+ with various divalent ions. Through a low-temperature solid-phase reaction method, a series of high-entropy LiMg0.9R0.1PO4 (R = Ni, NiCo, NiCoZn, NiCoZnCu, NiCoZnCuMn) ceramics were prepared successfully, and their MW dielectric properties were found to be heavily influenced by the ionic character, lattice energy, bond energy, entropy, ion radius disorder, and electronegativity of chemical bonds. Remarkably, LiMg0.9(Ni0.2Co0.2Zn0.2Cu0.2Mn0.2)0.1PO4 (LM5RP) ceramics exhibited exceptional MW dielectric properties (εr = 7.43, τf = − 27.6 ppm/°C, and Q × f = 83,216 GHz@13 GHz and 105,889 GHz@28 GHz) when sintered at an extraordinarily low temperature of 900 °C for 2 h. To demonstrate the real-world applicability of the LM5RP high-entropy ceramic, we designed and fabricated a state-of-the-art millimeter-wave (mmWave) filter, operating at 28 GHz, using low-temperature co-fired ceramic (LTCC) packaging technology. The filter exhibited unparalleled performance, featuring a low insertion loss (0.9 dB) and wide stopband suppression (> 17 dB @ 2.14 f0). These groundbreaking findings underscore the immense potential of high-entropy ceramics in revolutionizing advanced MW applications, particularly in the domain of B5G/6 G mmWave communication systems.

Новый катодный материал La2/3Cu3Ti4−xFex O12−δ для твердооксидного топливного элемента: синтез и электропроводность

Copper lanthanum titanate La2/3Cu3Ti4−xFexO12−δ x = 0–1 was doped with Fe3+ cations. The diagram of the dependence of the tolerance factor on the relative electronegativity of cations for all studied compositions was represented. It was shown that all the compositions exist in the region of existence of distorted perovskite. X-ray diffraction and X-ray phase analysis methods established the region of existence of solid solutions of La2/3Cu3Ti4−xFexO12−δ obtained by ceramic technology, which was 0 ⩽ x ⩽ 0.4. The temperature dependences of electrical conductivity for the compositions from the region of existence of solid solutions La2/3Cu3Ti4−xFexO12−δ were obtained. The ionic-electronic nature of conductivity was suggested. It was shown that the decrease of electronic conductivity under the increase of iron content was due to the compensation of electronic carriers formed during acceptor doping.

Impacts of P-site non-stoichiometry on the structure and properties of BaZnP2O7 ceramics

In this work, a series of P5+-enriched BaZnP2+xO7 ceramics were synthesized using the solid-state method at temperatures ranging from 825°C to 925°C. All ceramics exhibited a single triclinic phase. A suitable excess of P5+ promoted grain growth and densification, which also affected εr and Q×f. Subsequently, the relationship between total lattice energy and Q×f was explored, as well as the connection between total bond energy and τf. At 850°C, the BaZnP2.01O7 ceramics achieved a relative density of 97.7 % and demonstrated optimal properties: εr∼8.78, Q×f∼149,008 GHz, τf∼-28.92 ppm/°C. These ceramics present an outstanding combination of low εr, high Q×f and low sintering temperature, indicating their potential for application in Low-Temperature Co-fired Ceramics (LTCC) technology.

Industrial potential of additive manufacturing of transparent ceramics: A review

Transparent ceramics is a unique class of materials, with performance comparable to single crystals, but a high process flexibility given by ceramic technology. Currently, traditional ceramic shaping technologies reliably produce components but are limited in terms of shapes and the use of multiple compositions in a single component. The presented review aims to illustrate how the introduction of additive manufacturing (AM) technology in the production of transparent ceramic components opens new possibilities, both thanks to the high variability of shapes and thanks to the high precision in producing parts with a controlled variation of composition. Within this review, several AM techniques and their current state of the art are analysed, with focus on their advantages in producing transparent ceramics, along with the associated challenges and limitations. The future perspective and possibilities for an industrial production are discussed, with emphasis on the most promising AM techniques, direct ink writing and vat photopolymerisation, pointing out the future scenario for the transparent ceramics market.

Compressive Strength Analysis of Additively Manufactured Zirconia Honeycomb Sandwich Ceramic Parts with Different Cellular Structures

In this study, ZrO2 honeycomb sandwich structures with different cellular geometry were manufactured by SLA 3D-printing technology to analyze the compressive strength behaviour. After the printing procedure, the samples were sintered at 1450 °C for 2h. Among the samples with different cellular geometry, ZrO2 parts with circular cells were superior to that of square and triangular honeycomb structures and 1867±320 MPa compressive strength was obtained for this structure. The stress distributions in honeycomb structures were investigated using the COMSOL Multiphysics® for exposing the effect of cellular geometry on compressive strength. While more uniform stress distributions were seen on the inner wall of the circular honeycomb sample, the cellular structure of the square and triangle honeycomb samples mostly displayed compressive stress concentration on the joints of the honeycomb structure. Also, according to Rankine failure criterion, the parts with square cellular geometries were found to be more prone to failure. The highest specific compressive strength was obtained for the ZrO2 parts with circular cellular geometry. These findings demonstrated that the ZrO2 honeycomb sandwich structures with circular cellular geometry produced using SLA ceramic 3D-printing technology may be a suitable material to utilize in lightweight structural designs.

Cold sintering of α- and γ-modifications of aluminum oxohydroxides: A low-temperature route to porous corundum ceramics

Objectives. To obtain porous corundum ceramics using an innovative cold sintering process starting from different phase modifications of aluminum oxohydroxide — boehmite γ-AlOOH and diaspore α-AlOOH; to study the phase and structural properties of the resulting materials; and to assess their permeability to water.Results. Cold sintering enables the formation of single-phase corundum ceramics with an open porosity of 47.9% directly from the initial boehmite powder with the addition of 5 wt % corundum in the presence of 20 wt % water at a temperature of 450°C, mechanical pressure of 220 MPa, and isothermal exposure for 30 min. Under the same conditions of cold sintering, a mixture of diaspore and boehmite was transformed into α-AlOOH ceramics. This then turned into corundum with an open porosity of 39% when calcined in air at 600°C for 1 h. The resulting materials had permeability for pure water above 5000 L/(m2∙h∙bar).Conclusions. Cold sintering is a promising approach to producing porous corundum ceramics which can be used in filtration systems. Compared to traditional ceramic technology, the new approach reduces energy, time, and labor costs in the material manufacturing. It also eliminates the need to use auxiliary substances (binders, pore-forming agents, etc.).

APLICAÇÕES ESTÉTICAS DE PORCELANA NA ODONTOLOGIA CONTEMPORÂNEA – REVISÃO SISTEMÁTICA

Since the early 1800s, porcelain and ceramic materials have been used in the production of aesthetic dental restorations. Advances in dental ceramic technology and adhesive systems have made porcelain veneers a highly sought after aesthetic option. Thus, this work aims to review the literature, with the aim of discussing the use of porcelain veneers in modern dentistry, emphasizing their advantages, disadvantages, indications and limitations. The databases used were PubMed, SciELO, Google Scholar where a total of 21 articles published in the last 10 years were selected. The findings revealed that this technique has several indications and advantages, among its benefits are the minimal compromise of tooth wear during the tooth preparation phase and the achievement of harmony in the patient's smile, in addition to longevity. Its contraindications and disadvantages include, in some cases, detachments and fractures, among others.

APLICAÇÕES ESTÉTICAS DE PORCELANA NA ODONTOLOGIA CONTEMPORÂNEA – REVISÃO SISTEMÁTICA

Since the early 1800s, porcelain and ceramic materials have been used in the production of aesthetic dental restorations. Advances in dental ceramic technology and adhesive systems have made porcelain veneers a highly sought after aesthetic option. Thus, this work aims to review the literature, with the aim of discussing the use of porcelain veneers in modern dentistry, emphasizing their advantages, disadvantages, indications and limitations. The databases used were PubMed, SciELO, Google Scholar where a total of 21 articles published in the last 10 years were selected. The findings revealed that this technique has several indications and advantages, among its benefits are the minimal compromise of tooth wear during the tooth preparation phase and the achievement of harmony in the patient's smile, in addition to longevity. Its contraindications and disadvantages include, in some cases, detachments and fractures, among others.

Characteristics of low-temperature plasma for activation of plastic-degrading microorganisms

Plastic pollution is a problem that threatens the future of humanity, and various methods are being researched to solve it. Plastic biodegradation using microorganisms is one of these methods, and a recent study reported that plastic-degrading microorganisms activated by plasma increase the plastic decomposition rate. In contrast to microbial sterilization using low-temperature plasma, microbial activation requires a stable plasma discharge with a low electrode temperature suitable for biological samples and precise control over a narrow operating range. In this study, various plasma characteristics were evaluated using SDBD (Surface Dielectric Barrier Discharge) to establish the optimal conditions of plasma that can activate plastic-degrading microorganisms. The SDBD electrode was manufactured using low-temperature co-fired ceramic (LTCC) technology to ensure chemical resistance, minimize impurities, improve heat conduction, and consider freedom in designing the electrode metal part. Plasma stability, which is important for microbial activation, was investigated by changing the frequency and pulse width of the voltage applied to the electrode, and the degree of activation of plastic-degrading microorganisms was evaluated under each condition. The results of this study are expected to be used as basic data for research on the activation of useful microorganisms using low-temperature plasma.

Compαrαtive chαrαcteristics of luminescent detector mαteriαls bαsed on α-Αl2O3-δ for neutron dosimetry

The optically stimulated luminescence (OSL) and the separation efficiency of the neutron and gamma components by OSL outputs were studied for samples of anion-deficient corundum (α-Αl2O3-δ) in ceramic and single-crystal forms with various neutron converters. For OSL dosimetry in mixed gamma-neutron fields, a detector material synthesized using ceramic technology consisting of a mixture of OSL active α-Αl2O3-δ and neutron-converter 6LiF powders in a ratio of 7:3 was selected as a promising one. The lower limit of the individual dose equivalent for such material under neutron irradiation does not exceed 30 μSv, and the dose dependence is linear up to 1 Sv.

Technology and Dielectric Properties of BLT4 Ceramics Modified with Special Glass

Lead-boron special glass was doped into Ba0.996La0.004Ti0.999O3 (BLT4) ceramics in order to control the sintering process and grain growth, consequently obtaining materials with a well-developed microstructure. Changes in the microstructure resulted in a significant decrease in electrical permittivity along with a substantial increase in its frequency dispersion. Glass-doped ceramics, similar to pure BLT4, are characterized by a first-order phase transition from the ferroelectric phase to the paraelectric phase. The temperature of this transition shifts slightly towards higher values with the increase in glass dopant concentration.