Ceramic Elements Research Articles

Ceramization of coordinated Zr4+ and Hf4+ in polysiloxane conferring silicone/phenolic hybrid resin with excellent thermal protection

Silicon/phenolic hybrid resins are one of the most commonly used materials for thermal protection. However, the weak ability of SiO2 generated by silicone during ablation to resist the impact of high-speed hot gas flow hinders further improvement of the performance. Therefore, in this work, the ultrahigh-temperature ceramic elements Zr4+ and Hf4+ were integrated into hyperbranched polysiloxanes in the form of coordination bond and then introduced into phenolic resin (PR), obtaining hybrid resin with excellent ablative resistance. During ablation, Zr4+ and Hf4+ will first undergo ceramization, producing ZrO2 and HfO2. Subsequently, they will undergo a solid solution sintering reaction to produce complex-phase ceramic particles (ZrxHf1-x)O2, which are embedded in the SiO2 liquid film and provide excellent pinning effect. This gives the hybrid resin excellent ablation resistance, whose linear ablation rate can be as low as 0.038 mm/s, a 58 % decrease compared to pure PR. This work not only provides a new pathway for ceramization through metal ion coordination bonding, but also provides a new way to prepare high-performance TPS materials.

Effect of additive type and amount on structural and mechanical properties of ZrO2/B4C/Al2O3/SiC added Al 1050 based composite structures produced by vacuum infiltration—Comparative study

With this experimental study, ZrO2/B4C/Al2O3/SiC ceramics in different weight ratios were added to 99.5% pure aluminum and composites were produced by vacuum infiltration, which is very rare in the literature. It is aimed to investigate how different ceramics will affect the technical properties of an aluminum composite. First, scanning electron microscope images were taken to examine their microstructures, and energy-dispersive x-ray spectroscopy analyses were performed. In addition, x-ray diffraction analyses of phase structures were performed. Then, the densities of the composite structures were measured. In the last stage of the experiments, hardness measurement, bending strength, and abrasive wear amount tests were carried out to determine the mechanical properties of the composite structures. According to the data obtained, a relatively homogeneous structure was obtained up to 10% of the ceramic particles in the structure. It was observed that thermal damage did not occur in the composite structures and no significant phase changes occurred. The highest infiltration distance was obtained from B4C-reinforced samples, and the lowest infiltration distances were obtained from ZrO2-reinforced samples. Ceramic reinforcement elements have reduced the density values of composite structures. With the increase in the ratio of ceramic reinforcement particles, the hardness values of the composites increased and the flexural strength values decreased. In the abrasive wear tests, the least wear loss was obtained from SiC-reinforced samples and the highest wear loss was obtained from ZrO2-reinforced samples. When the composites were evaluated according to their microstructure and mechanical strength, the best results were obtained with SiC and then Al2O3, B4C, and ZrO2 reinforcements, respectively. It has been concluded that SiC, Al2O3, B4C, and ZrO2 reinforcement elements in Al 1050-based composites produced by vacuum infiltration have a positive effect on most of the mechanical properties and a negative effect on some of them.

3D printing PMN-PT textured ceramics for transducer applications

3D printing stereolithography (SL) technique were successfully applied in the preparation of <001>-textured 0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 (PMN-29PT) ceramics in this work. The as-sintered textured ceramics show obvious grain orientation control effects, and the relative density reaches 93% of the theoretical density. The obtained ceramics demonstrate typical dielectric/ferroelectric/piezoelectric properties, enabling the device applications. The ultrasonic transducer with the center frequency of 6.7 MHz and the −6 dB bandwidth of 25% are designed and prepared based on the obtained textured ceramic. This work signifies the great potential of 3D printing SL technology on the fabrication of piezoelectric ceramic elements for advanced applications.

Localization of Vapors of Cesium Iodide on Ceramic Block-Cellular Contact Elements in an Oxidizing Environment

Localization of Vapors of Cesium Iodide on Ceramic Block-Cellular Contact Elements in an Oxidizing Environment

Traveling wave thermoacoustic refrigeration with variable phase-coordinated boundary conditions.

Thermoacoustic refrigerators exploit the thermodynamic interaction between oscillating gas particles and a porous solid to generate a temperature gradient that provides a cooling effect. In this work, we present a resonator with dual enclosed driver end-caps and show that the temperature gradient across a ceramic thermoacoustic element placed in the cavity could be controlled by modifying the phase difference of the drivers, thus enabling precise control of the refrigeration capability via the temperature difference. Through deltaec simulation results, the response of the temperature gradient to various dynamic boundary conditions that alter the time-phasing and wave dynamics in the resonator are demonstrated. An experimental apparatus is constructed with two moving-coil speakers and a ceramic stack, which is shown to exhibit a temperature gradient along its length, based on the traveling-wave-like nature of the acoustic wave excited by the speakers. By adjusting the relative phase lag between the two speakers, the temperature gradient across the stack is made to increase, decrease, or flip sign. Finally, a desired temperature difference that changes in time is achieved. The results presented in this work represent a key conceptual advancement of thermoacoustic-based temperature control devices that can better serve in extreme environments and precision applications.

Coextrusion of Clay-Based Composites: Using a Multi-Material Approach to Achieve Gradient Porosity in 3D-Printed Ceramics

3D printing of ceramics has started gaining traction in architecture over the past decades. However, many existing paste-based extrusion techniques have not yet been adapted or made feasible in ceramics. A notable example is coextrusion, a common approach to extruding multiple materials simultaneously when 3D-printing thermoplastics or concrete. In this study, coextrusion was utilized to enable multi-material 3D printing of ceramic elements, aiming to achieve functionally graded porosities at an architectural scale. The research presented in this paper was carried out in two consecutive phases: (1) The development of hardware components, such as distinct material mixtures and a dual extruder setup including a custom nozzle, along with software environments suitable for printing gradient materials. (2) Material experiments including material testing and the production of exemplary prototypes. Among the various potential applications discussed, the developed coextrusion method for clay-based composites was utilized to fabricate ceramic objects with varying material properties. This was achieved by introducing a combustible as a variable additive while printing, resulting in a gradient porosity in the object after firing. The research’s originality can be summarized as the development of clay-based material mixtures encompassing porosity agents for 3D printing, along with comprehensive material-specific printing parameter settings for various compositions, which collectively enable the successful creation of functionally graded architectural building elements. These studies are expected to broaden the scope of 3D-printed clay in architecture, as it allows for performance optimization in terms of structural performance, insulation, humidity regulation, water absorption and acoustics.

Evolutionary design method for transforming ceramic cultural elements into cultural and creative products

Cultural and creative products are empowered through cultural connotation in the market with ever-changing customer needs. Analyzing user preferences and matching them with product design elements has become the focus of research. Taking ceramic bracelet as the research example, this study proposed an evolutionary system which integrates the interactive genetic algorithm with artificial neural network and fuzzy analytic hierarchy process based on evaluation grid method. First, the cultural genes were extracted from cultural products as the design elements. Second, the attractiveness characteristics of the products and customer demand dimension information were analyzed by evaluation grid method. Third, the fuzzy analytic hierarchy process was used to assign weight values to the 3 users’ perceptual evaluation vocabularies. Fourth, the artificial neural network algorithm was incorporated into the fitness evaluation stage of the interactive algorithm to reduce information distortion caused by evaluation fatigue. Finally, after training the samples using the back propagation neural network, 8 design schemes with a fitness value exceeding 4.5 were obtained. The iterative curve indicated that after the 51st generation, the error accuracy approached 0.09. The experimental results verified that the system could help to improve the efficiency of product design, and design products that are more in line with user needs.

Functionalization of All-Oxide Ceramic Matrix Composites Elements Using Three-Dimensional Braiding and Pressure Slip Casting for Composite Processing: Approaches to Reduce the Filter Effect of Dense Reinforcement Textiles

Abstract A key element for the transition to sustainable energy lies in the transformation of the power plant fleet, which is dominated by fossil fuels, toward sustainable energy production from renewable energy sources. An increase in efficiency and reduction of exhaust gas emissions, especially the minimization of CO2 emissions, is possible through the use of new turbine materials, which can withstand higher temperature levels. Oxide ceramics are well known for their high stability in aggressive environments, low density, high melting point, high stiffness, and great creep resistance, but their brittleness has strongly limited their number of applications. Therefore, the implementation of fiber reinforcement using the three-dimensional (3D) braiding process shows great potential to increase the damage tolerance of ceramic matrix composites (CMC) and consequently the performance of thermal machines significantly. Currently, the impregnation of 3D braids for the reinforcement of ceramic composites poses a challenge due to the high packing density of the textiles. In order to enable a homogeneous impregnation of the fiber structures using highly viscous ceramic slurries, the CMC research group at RWTH Aachen University's Institute of Textile Technology (ITA) is investigating the combination of 3D braiding and pressure slip casting for an economical production of all-oxide CMCs. To increase the impregnation quality of dense textiles, this paper describes approaches to reduce the filter effect of braids. The results of an initial investigation into the functionalization of two-dimensional braided reinforcement structures by using support structures and flow aids are described. The effectiveness of the impregnation ability is assessed by evaluating the residual porosity of generated green compacts via μCT analysis.

CURRENT TRENDS IN THE DEVELOPMENT OF HIGH-ENERGY LASERS

Current trends in developing high-energy lasers with pulse energies in the tens and hundreds of joules are considered. Active media are analyzed for their use in such lasers. Yb:YAG active crystalline and ceramic elements (AE) of Russian production are experimentally investigated at temperatures from 100 K to 295 K. The data of the AE cryogenic cooling system are presented. A diode pumping system for AE and a homogenizer of its radiation are described. The physical and technical characteristics of the pumping system are given. Fresnel losses, absorption losses, and losses due to amplified spontaneous emission (ASE), which reduce the energy stored in an inverted population, are experimentally measured. The results of measuring the gain in multipass circuits with different sets of AEs are presented.

Localization of Vapors of Cesium Iodide on Ceramic Block-Cellular Contact Elements in an Oxidizing Environment

Localization of Vapors of Cesium Iodide on Ceramic Block-Cellular Contact Elements in an Oxidizing Environment

The investigation of the contact and wear of railway axle bearings under various race conformities

The bearing race conformity is a design parameter that determines the degree of contact between rollers and races. This paper investigates the effect of race conformity on wear distribution in a railway spherical roller bearing under boundary lubricated condition in which contact behaves like a dry contact. The results showed that the traction/micro-slip distributions were substantially dependent on the level of conformity. The wear is found to be highly sensitive to the race conformity, with lower conformity resulting in lower wear. For example, 5.2% increase of conformity factor, a parameter that represents race conformity mathematically, reduces worn area by 52% in inner contact that is 60% in outer contact where conformity factor increase is 5.8%. This is mainly due to high value micro-slip being truncated at the edges as the traction distribution is compressed into the smaller contact patch. The bearings with ceramic rolling elements show lower wear than for steel rolling elements due to lower wear coefficient. The higher elastic modulus of ceramic causes the traction magnitude to be higher in the ceramic-steel case over the steel-steel case. Therefore, race conformity can be taken into consideration to optimize roller bearing wear life.

Intelligent Element Layout Algorithm of Ceramic Design Drawing Based on Genetic Algorithm

Conventional intelligent layout algorithm of ceramic design drawing elements mainly uses density distribution method to obtain ceramic design drawing element units, which is vulnerable to the influence of pattern density, resulting in a low distribution balance of design drawing elements. Therefore, a new intelligent layout algorithm for ceramic design drawing elements needs to be designed based on a genetic algorithm. That is, combining the characteristics of ceramic design drawing elements, the intelligent parting structure of ceramic design drawing elements is constructed, and then the brilliant layout model of ceramic design drawing elements is designed using genetic algorithm. The experimental results show that the developed intelligent layout algorithm of ceramic design elements has a high distribution balance, which proves that the designed intelligent layout algorithm of ceramic design elements has good performance, reliability, and certain application value, and has made specific contributions to improving the aesthetic quality of ceramic design drawings.

The effect of Sr2+ and thermal treatment conditions on electrochemical characteristics of Li3OCl solid electrolyte in batteries

Lithium-rich oxychloride anti-perovskite solid electrolytes have the potential to be promising for the next generation of batteries. Here, the influence of Sr2+ doping and heat treatment regime on the structure evolution, microstructure, and electrochemical properties of Li3–2xSrxOCl prepared by the hydrothermal route was reported. This research shows that both strategies of doping Sr2+ and the thermal treatment conditions lead to increase ionic conductivity. The lithium-ion conductivity increased with doping Sr2+ content and reached a maximum by x = 0.007 substitution of Sr2+ for Li+. A novel sintering approach is employed with ceramic elements for faster heat treatment that provids more homogeneity with a lower penetration barrier for lithium ions to diffuse in comparison with regular sintering in a furnace. Through this technique, the Li3-2×0.007Sr0.007OCl composition shows a high ionic conductivity of 0.38 × 10−3 S cm−1 at 60 °C. According to differential scanning calorimetry (DSC) measurements, the secondary hydroxide phases were found to have been transformed into the Li3-2xSrxOCl phase upon the first heat treatment cycle. Furthermore, the chemical stability of the Li/Li3-2×0.007Sr0.007OCl/Cu electrochemical cell was verified by cyclic voltammetry at 130 °C during lithiation/delithiation in a wide potential window (−1 to 8 V). The total impedance of the interfaces (RB) and the impedance of the bulk electrolyte (RA) in Li/ Li3-2×0.007Sr0.007OCl /NCM half-cell were obtained at 3690 and 723 Ω, respectively. The electrochemical stability of the Li3-2×0.007Sr0.007OCl electrolyte in contact with lithium metal is confirmed by chronopotentiometry test during charge/discharge conducted for 216 h at 60 °C. Moreover, the charge/discharge performance of Li/ Li3-2×0.007Sr0.007OCl/NCM half-cell showed an initial discharge capacity of 163 mAh/g and a discharge efficiency of 80 % after 20 cycles.

Application of Digital Ceramic Art Elements in the Landscape Design of Rural Ecological Environment Based on Virtual Reality

Application of Digital Ceramic Art Elements in the Landscape Design of Rural Ecological Environment Based on Virtual Reality

PRODUCTION TECHNOLOGY OF RADIO-TRANSPARENT CERAMIC MATERIALS

Ceramic radiotransparent materials are non-metallic materials that ensure the transmission of electromagnetic radiation in the radio frequency range of 105–1012 Hz with minimal dielectric losses in the operating temperature range (tgδ 10-2–10-5, ε &lt; 10) and a low value of the radio wave reflection coefficient (P &lt; 1 %). Ceramic radiotransparent materials are used to create rocket and aircraft fairings that protect antenna systems from external factors. For the synthesis of radiotransparent ceramic materials, it is expedient and promising to use such crystalline phases as celsian (BaAl2Si2O8) and slawsonite (SrAl2Si2O8) due to their low dielectric constant and dielectric loss tangent, as well as rather high thermal stability and melting point compared to other aluminosilicate compounds (mullite, spodumene, cordierite, etc.). The development of technology for obtaining radio-transparent ceramic antenna fairings and elements of protective structures of antenna systems of aviation facilities based on the BaO (SrO) – Al2O3 – SiO2 system is relevant. For the formation of complex profile ceramic radiotransparent materials slurry casting in porous gypsum molds is used. In order to compare the developed ceramic compositions, the physico-mechanical, dielectric and electrodynamic properties were studied under normal conditions and in the millimeter frequency range (26-38 GHz). As a result of the research, the following have been developed: a technology for the production of ceramic radiotransparent materials based on slawsonite by semi-dry pressing method, based on celsian-slawsonite by slip casting method and based on celsian or slawsonite by slip casting method. It has been established that the developed materials meet the technical requirements for radio-transparent ceramic materials and can be used to produce elements of protective structures of antenna equipment, such as nose fairings for aircraft.

Vibration Characteristics of Piezoelectric Ceramic Elements with Large Anisotropy and Their Application in Ultrasonic Probes

Vibration Characteristics of Piezoelectric Ceramic Elements with Large Anisotropy and Their Application in Ultrasonic Probes

ТЕХНОЛОГИЯ ИЗГОТОВЛЕНИЯ ЧУВСТВИТЕЛЬНЫХ ЭЛЕМЕНТОВ ДАТЧИКОВ ДАВЛЕНИЯ НА ОСНОВЕ СПАЯ САПФИР – СТЕКЛОВИДНЫЙ ДИЭЛЕКТРИК – КЕРАМИКА

Today pressure transmitters have high requirements such as reliability, quality, measurementaccuracy, the ability to work in extreme conditions and resistance to aggressive environments.The main problems in achieving these target indicators are: the high cost of the originalproducts, the laboriousness of the technological process in serial production, and the limitationsthat affect the accuracy of the indicators of the original devices. Solving these problems is thesubject of this article. To solve these problems and improve the physical and mechanical propertiesof pressure sensor’s sensitive elements, the following tasks are considered in the article: developmentof a pressure-sensing element design based on the silicon-on-sapphire (SOS) structureresearch on the method of its connection with a ceramic body element and development of a technologicalroute for manufacturing the structure based on “sapphire – vitreous dielectric – ceramic”junction. As a result, the pressure sensor based on the SOS structure has high sensitivity,stability, practically no mechanical hysteresis, and can operate in a wide temperature range from-60 to +350°C when exposed to radiation. In turn, the use of a ceramic base makes it possible toreduce the temperature error of the sensor due to better matching of the coefficient of linear thermalexpansion (CLTE) of ceramic (85–100×10-7 K-1) and sapphire substrate (60–75×10-7 K-1), aswell as reduce the cost of the technological process due to the use of ceramics instead of expensivetitanium alloys and complex metalworking. Thus, the structure "sapphire – vitreous dielectric –ceramic" shows the possibility of increasing the sensitivity of the sensor and reducing the errorwhile expanding its functionality, simplifying the design and improving manufacturability

A novel low temperature and low loss Ba2Bi2/3TeO6 microwave dielectric ceramic with double perovskite structure for LTCC applications

This research demonstrates the microwave dielectric properties of Ba2Bi2/3TeO6 ceramics, synthesized for the first time via the solid-state method, for LTCC applications. The analysis of X-ray diffraction (XRD) patterns and structural refinement verify the double perovskite structure of Ba2Bi2/3TeO6 ceramics. Transmission electron microscopy (TEM) validates the ordered layered structure of the double perovskite Ba2Bi2/3TeO6 ceramics. Scanning electron microscopy (SEM) characterizes the grain microstructure, revealing a relative density of 99.1% for the sample. An inverse proportionality is observed between the Raman full-width at half maximum (FWHM) and the Q × f value. X-ray photoelectron spectroscopy (XPS) elucidates the chemical composition and valence states of the Ba2Bi2/3TeO6 ceramic elements. The microwave dielectric properties of Ba2Bi2/3TeO6 ceramics calcined at 935 °C were discovered to be εr = 11.94, Q × f = 21,579 GHz (f = 9.8 GHz), and τf = −22.4 ppm/°C. Ba2Bi2/3TeO6 ceramics emerge as an excellent candidate for LTCC applications.

Vibration Signal Diagnostic Information of Reinforced Masonry Elements Destruction

Reinforced masonry constructions and their elements must meet strength and stability requirements. These conditions determine wall structure safety during construction and operation. Safety depends on diagnostically aimed tests that check the objects’ quality or locate damages to structural elements that arise during operation. This article is focused on the experimental modal analysis research of reinforcement ceramic masonry elements. The aim of the research was to check whether it is possible to observe the damage in reinforced masonry structures and the accompanying vibration of signal transition functions by conducting pilot studies and using different types of reinforcements. The experiment was conducted on three samples of various types of reinforced brick walls. During the vibration tests, the segments were subjected to various loads, and it was observed how the increasing cracks and damage changed the courses of the measured functions of the vibration process, reflecting the damage to the segments. This made it possible to assess the variability of the vibration characteristics of the tested reinforced wall elements and the usefulness of the applied test method. The aim of the study was to check the assessed effectiveness by testing the degradation of the reinforced wall elements. The research confirmed the usefulness of the SISO methodology in identifying damages, which has been implemented in selected precast factories in Poland.

3D Printing of Ceramic Elements with Q-Surface Geometry for the Fabrication of Protective Barrier

The work proposes the use of aluminum oxide-based ceramic objects with a TPMS-Q-surface geometry as elements of armor structures. The samples were produced using the SLA-DLP 3D printing method. The main properties of the sample were determined using physical-chemical analysis methods: apparent density ρap = 3.6 g/cm3, open porosity Popn = 8.5%, microhardness Hµ = 15.3 GPa, water absorption W = 2.4%, elastic modulus E = 405 GPa. The Stiglich criterion M = 1.72 EPa2·m3/kg, and the Shevchenko criterion K = 0.8.