High Temperature Ceramic Materials Research Articles

Comparison of ZrB2-SiC, HfB2-SiC and HfB2-SiC-Y2O3 oxidation mechanisms in air using LIF of BO2(g)

The oxidation behaviour of ZrB2-SiC, HfB2-SiC and HfB2-SiC-Y2O3 is studied using the real-time Laser-Induced Fluorescence (LIF) detection of BO2(g) evaporated from samples heated up to 1873K in dry air. For each composition, the relevant steps of oxidation (silica formation, volatilization, etc.) can be precisely determined. Moreover, the influence of composition on the oxidation behaviour, and more precisely on the B2O3/SiO2 ratio in the glassy phase, can be understood and described by monitoring the LIF signal from the BO2(g) radical. Thus, this technique has confirmed the potential of the HfB2-SiC-Y2O3 composition as a Ultra High Temperature Ceramic (UHTC) material.

Inspection of thermal stress parameters of high temperature ceramics and energy absorber materials

Thermal stress of ceramics and high temperature materials have gained much attentions in the recent years due to their involving and increasing interest in highly advanced and severe applications. However, ceramic materials experience a high degree of brittleness and sensitivity to mechanical damage under thermal and mechanical loadings. This in turn promote the generation of thermal stresses of high magnitude. Catastrophic thermal stress failure of ceramic materials affects mainly on their successful implementation in high temperature and energy applications. Concept of thermal stress, its causes, consequences and ways to prevent its distressing failure should be inclusively studied and introduced. Moreover, due to the increased importance of solar radiation and its great role in solving the global energy deficiency problem, much efforts and studies should be exerted in overcoming the thermal stress generated among its components. So that, this article will handle several aspects concerning the thermal stress of high temperature ceramic materials. Besides, its causes and different ways to enhance thermal stress durability and resistance will be included. In addition, for the first time we will discuss the direct relationship between the thermal stress, thermoelectricity and solar energy absorption. Finally, inclusive studies on thermal stress of laminated and multilayer composites will be covered and investigated.

Prospects of Nanotechnology and Design of Materials Based on Refractory Compounds

The prospects for the development of high-temperature ceramic materials science are considered as a matter of discussion. The substantiation of the development of hetero-modulus ceramic composites as the possibility to implement unique physicochemical features of refractory compounds (carbides, nitrides, borides, etc.) under their application conditions at high and ultrahigh temperatures is presented. The prospects for a nanotechnology-based approach to the fabrication of such materials in engineering are shown.

Effect of ZrB2 Particle Size on Pressureless Sintering of ZrB2 - ß-Sic Composites

Zirconium diboride is an ultra high temperature ceramic material that leads this emerging class of materials because of its distinct combination of properties, including high melting temperature (> 3000 °C) and the lowest theoretical density (6.09 g·cm-3) among the borides. This combination of properties makes ZrB2 candidate for airframe leading edges on sharp-bodied reentry vehicles. In this work, the effect of particle size of ZrB2 on the pressureless sintering of ZrB2-SiC composites was studied, using ZrB2 powder with average particle size of 2.6 and 14.2µm. Four different vol% concentration of ß-SiC (0, 10, 20 and 30 vol%) were added to as-received and planetary milled ZrB2 powder. Samples were pressureless sintered at 2050 °C/1h in argon atmosphere. The reduction of initial ZrB2 particle size led to composites with better results of densification, mechanical properties and oxidation resistance regardless ß-SiC addition, showing relative densities around 92.5 %Theoretical Density (Td) and flexural strength and microhardness around 260 MPa and 17.5 GPa, respectively. Composites processed with as-received ZrB2 powder showed increasing in densification and flexural strength with the SiC content increasing. Relative density varied from 74.7 to 90.8 %TD and flexural strength from 102 to 241 MPa, for 0 and 30 vol% of SiC, respectively.

High-Temperature Ceramic Material with the Increased Erosive Firmness

Research & Development in Material Science High-Temperature Ceramic Material with the Increased Erosive Firmness Kharitonov DV*, Anashkina AA, Kulikova GI, Sher NE and Baranov SV JSC «ORPE «Technologiya» named after A. G. Romashin (Russia, Obninsk) *Corresponding author:Kharitonov DV, JSC «ORPE «Technologiya» named after A. G. Romashin (Russia, Obninsk) Submission: May 17, 2019;Published: May 22, 2019 DOI: 10.31031/RDMS.2019.11.000751 ISSN: 2576-8840 Volume11 Issue1

Lead-free 0.7BiFeO3-0.3BaTiO3 high-temperature piezoelectric ceramics: Nano-BaTiO3 raw powder leading to a distinct reaction path and enhanced electrical properties

Herein, nano-BaTiO3/Bi2O3/Fe2O3 and BaCO3/TiO2/Bi2O3/Fe2O3 were respectively used to prepare 0.7BiFeO3-0.3BaTiO3 (0.7BF-0.3BT) ceramics by conventional solid-state method and clarify the reaction path, phase structure, microstructure, ferroelectric, and piezoelectric properties. 0.7BF-0.3BT ceramic using nano-BaTiO3 with cubic phase (CBT) undergoes the formation of rhombohedral α-phase (Rα) and the transition from Rα and CBT to rhombohedral β-phase (Rβ) and pseudo-cubic (PC) phases, while the counterpart using BaCO3/TiO2 directly generates Rβ and PC. Nano-BaTiO3 can decrease pores and oxygen vacancies in the resultant ceramics comparing to BaCO3/TiO2, which is due to an inhibited decomposition of Rα and a weaker reduction of Fe3+ to Fe2+, leading to increased density and reduced leakage current density. Benefitting from a proper phase ratio, increased density and reduced leakage current density, the enhanced piezoelectric properties d33 = 210 pC/N, kp = 0.34, Pr = 31.2 μC/cm2 and TC = 514 °C are obtained in 0.7BF-0.3BT ceramic using nano-BaTiO3. Our work reveals the importance of raw materials and the potential of BF-BT as a high-temperature lead-free piezoelectric ceramic material.

Prospects of nanotechnology and materials design on the basis of refractory compounds

As a matter of discussion, the prospects for the development of high-temperature ceramic materials science are considered. The paper provides a rationale for developing hetero-modulus ceramic composites as a possibility to implement the unique physicochemical properties of refractory compounds (carbides, nitrides, borides, etc.) under the conditions of their application at high and ultra-high temperatures. The prospects of nanotechnology-based approach to the preparation of similar materials in engineering practice are shown.

Additive Manufacturing and size-dependent mechanical properties of three-dimensional microarchitected, high-temperature ceramic metamaterials

Abstract

Low temperature synthesis process of stabilization of cubic yttria stabilized zirconia spindles: an important high temperature ceramic material

Yttria stabilized zirconia (YSZ) is one of the promising materials for thermal barrier coating. In the present study, YSZ nanostructures have been synthesized in presence of a nonionic surfactant (Triton X-100) at low temperature (120 °C) using hydrothermal route. Our key observation is ‘Zirconia’ forms as spherical particles while ‘Yttria’ prefers the rod-like morphology in the presence of Triton X-100. Doping Yttria in zirconia up to 3 mol % (3YSZ), leads to the formation of rod-shaped Yttria (length = 100 nm, width = 25 nm) decorated with zirconia nanoparticles. However, increasing dopant concentration to 8 mol %, spindle shaped-particles (tip = 2 nm, width = 42 nm, length = 100 nm) were observed for the first time. These yttria doped zirconia show good thermal stability up to1200 °C (weight loss ~6–12%) without any secondary phase formation.Highlights • Cubic Yttria stabilized zirconia were synthesized at low temperature by hydrothermal route • Thermal stability of 8YSZ shows 5.5% weight loss only up to 1200 °C. • Doping of Yttria in zirconia leads to change in the morphology of the product. • Yttria prefers formation of the anisotropic shape of the product.

ИССЛЕДОВАНИЕ ТЕРМОХИМИЧЕСКОГО ВОЗДЕЙСТВИЯ ПОТОКА ВОЗДУШНОЙ ПЛАЗМЫ НА ВЫСОКОТЕМПЕРАТУРНЫЙ КЕРАМИЧЕСКИЙ КОМПОЗИЦИОННЫЙ МАТЕРИАЛ

ИССЛЕДОВАНИЕ ТЕРМОХИМИЧЕСКОГО ВОЗДЕЙСТВИЯ ПОТОКА ВОЗДУШНОЙ ПЛАЗМЫ НА ВЫСОКОТЕМПЕРАТУРНЫЙ КЕРАМИЧЕСКИЙ КОМПОЗИЦИОННЫЙ МАТЕРИАЛ

(Invited) Impedance Characterization of High-Temperature Spinned Fiber Ceramic Materials

Materials based on cubic ZrO2 stabilized with Y2O3 have good ionic conductivity at higher temperatures, which makes them suitable or promising candidates for use as a membrane in the solid oxide fuel cells (SOFC). The zirconia materials are mainly used as a compact ion conductive membrane, allowing the separation of the positive and negative electrodes while allowing ionic conduction via the oxygen ion. Another possible use in SOFC consists in the idea of creating a highly porous structure coated with a suitable catalyst (e.g., Ni) for the negative electrode. This would lead to a rapid increase in the active surface of the electrode and thereby increase the nominal current density of the fuel cell. The fibrous structure and its large porosity, while ionically bonding, appear to be very suitable for this purpose. The methods of forming fibers in our laboratory are both the force spinning and electrospinning. From the spinned nanofibrous materials we prepared disc samples (pellets) with opposite flat sides coated with a conductive platinum paste and wee annealed. The prepared samples were contacted using platinum mesh electrodes (a two-electrode connection) to the heated chamber of instrument ProboStat (Dept. of Chemistry, University of Oslo). The whole probe device shrouded in ceramic tube was inserted into a tubular furnace. The sample was held at different temperatures and the impedance spectroscopy data were obtained for a series of temperatures. From this the total impedance of the system, as a function of temperature, was collected. A relative simple equivalent circuit was used to fit the data end extract mostly the conductivity of the sample at each given temperature. Impedance was collected using spectrometer Solartron 1260 at suitable temperature steps (usually 25 ° C) at AC amplitude 100 mV. The equivalent circuit fit was done using ZView (Scribner Associates). Fig. 1 shows an example of impedance plot compared for a bulk (nonfibrous) substrate and one, with prepared from the fibrous material. The conductivity of ceramic materials is a thermally activated process, and therefore depends on temperature. Thermal conductivity changes are often described using the Arrhenius. In this case, the dependence of the logarithmic conductivity changes upon change of the inverse of the absolute temperature is linear and from the slope of the Arrhenius plot one can calculated the activation energy of the process (Fig. 2). From the figure it is apparent that the bulk and the fibrous material the activation energies are essentially identical, while the actual conductivities are significantly different for each; expectedly lower for the fibrous substrate. Figure 1

Electrical Performance of a 32-I/O HTCC Alumina Package for High-Temperature Microelectronics

A high-temperature cofired ceramic (HTCC) alumina material was previously electrically tested at temperatures up to 550°C and demonstrated improved dielectric performance at high temperatures compared with the 96% alumina substrate that we used before, suggesting its potential use for high-temperature packaging applications. This article introduces a prototype 32-input/output (I/O) HTCC alumina package with platinum conductor for 500°C low-power SiC-integrated circuits. The design and electrical performance of this package, including parasitic capacitance and parallel conductance of neighboring I/Os from 100 Hz to 1 MHz in a temperature range from room temperature to 550°C, are discussed in detail. The parasitic capacitance and parallel conductance of neighboring I/Os of this package in the entire frequency and temperature ranges measured do not exceed 1.5 pF and 0.05 μS, respectively. SiC-integrated circuits using this package and a compatible alumina circuit board have been successfully tested at 500°C for more than 3,736 h continuously, and at 700°C for more than 140 h. Some test examples of SiC-integrated circuits with this packaging system are presented.

Prospects for using high-temperature ceramic and glass-ceramic materials and antioxidant coatings in aeronautical engineering

The study focuses on the prospects and advantages of high-temperature ceramic, glass-ceramic materials and oxidation-resistant coatings use for fabrication of high-speed aircraft structures. The paper describes achievements of Federal State Unitary Enterprise “All-Russian Research Institute of Aircraft Materials” in the field of ceramic materials development via hybrid method of spark plasma sintering, sol-gel method and thermochemical synthesis. Moreover, the article shows the research results concerning the development of oxidation-resistant coatings for C/SiC and C/C materials.

Laboratory, on-ground and in-flight investigation of ultra high temperature ceramic composite materials

The capsule SHARK (Sounding Hypersonic Atmospheric Re-entering “Kapsule”) was designed and realized for testing in real flight conditions a ZrB2-based Ultra High Temperature Ceramic (UHTC) Nose Tip. The capsule was instrumented with accelerometers, rate and pressure sensors, and thermocouples of which three were inserted inside the UHTC Nose Tip.The capsule was launched by the European Space Agency (ESA) rocket MAXUS-8 performing an atmospheric re-entry after a parabolic trajectory with an apogee at 700 km of altitude.The temperature profile recorded by the thermocouples inserted inside the Nose Tip reported a discontinuity at about 762 s after the release from the rocket, revealing the failure of the ceramic component during the flight. The capsule was recovered and the Nose Tip was found damaged: the fore half was missing while the inner part, fractured in three pieces, was recovered.The fractographic analysis of the three recovered fragments was carried out by optical microscopy techniques which allowed identifying the main fracture marks, such as fracture mirror, hackle lines, arrest lines, and Wallner lines.The fracture dynamic has been outwardly reconstructed and the stress at fracture was evaluated by means of the Orr's equation involving the measurement of the fracture mirror radius. Then applying the Griffith's relationship, the flaw size was estimated. The origin of the main fracture was identified on the edge of the hole manufactured by Electrical Discharge Machining (EDM) to lodge thermocouples inside the nose tip, causing the strength-limiting flaw.Thermal shock was recognized as the probable failure cause as already observed by on-ground tests performed in the Plasma Wind Tunnel (PWT) “Scirocco” by the Italian Aerospace Research Centre (CIRA) on a similar UHTC Nose Tips manufactured with the same machining technology.

ВЫСОКОТЕМПЕРАТУРНЫЕ РАДИОПРОЗРАЧНЫЕ КЕРАМИЧЕСКИЕ КОМПОЗИЦИОННЫЕ МАТЕРИАЛЫ ДЛЯ ОБТЕКАТЕЛЕЙ АНТЕНН И ДРУГИХ ИЗДЕЛИЙ АВИАЦИОННОЙ ТЕХНИКИ (обзор)

ВЫСОКОТЕМПЕРАТУРНЫЕ РАДИОПРОЗРАЧНЫЕ КЕРАМИЧЕСКИЕ КОМПОЗИЦИОННЫЕ МАТЕРИАЛЫ ДЛЯ ОБТЕКАТЕЛЕЙ АНТЕНН И ДРУГИХ ИЗДЕЛИЙ АВИАЦИОННОЙ ТЕХНИКИ (обзор)

Reaction kinetics of mechanically activated cordierite-based ceramics studied via DTA

Since cordierite, 2MgO·2Al2O3·5SiO2 (MAS), is a very useful high-temperature ceramic material, it is important to decrease its sintering temperature. In order to accelerate the process of sintering, 5.00 mass% MoO3 was added to the starting mixtures. The mechanical activation of the starting mixtures was performed in a high-energy ball mill in time intervals from 0 to 160 min. After the activation, starting mixtures were sintered at 1300 °C for 2 h. In order to determine the impact of mechanical activation on particle size distribution and powders morphology, the mechanically treated powders were characterized by a laser light-scattering particle size analyzer and scanning electron microscopy. The phase composition of the starting mixtures and sintered samples was analyzed by the X-ray diffraction method. In order to determine temperature intervals of chemical reactions and phase transitions, differential thermal analyses (DTA) and thermo-gravimetric analysis were used. Kissinger’s equation was employed to calculate apparent activation energies of various processes that occur within the system during heating. Based on the obtained DTA results, it was established that mechanical activation along with MoO3 additive has influence on sintering temperature which was decreased for more than 100 °C, comparing to the literature data.

Insulation Performance of Heat-Resistant Material for High-Speed Aircraft Under Thermal Environments

Lightweight insulation materials are widely used to thermally protect high-speed aircraft, such as missiles. Thermal conductivity is an important parameter used to evaluate the efficiency of a material’s thermal insulation performance. Since thermal conductivities provided from material handbooks or manufacturers are discrete data for different temperature ranges, there is a deviation between those and actual parameters in terms of continuous nonlinear variations. Therefore, this study measures the thermal conductivities of lightweight thermal insulation materials at high temperatures, and the relationship between the thermal conductivity and temperature is obtained. A finite element model of the thermal insulation materials is also established and applied to numerically calculate the thermal insulation properties for high-temperature ceramic fiber insulation materials using the experimentally obtained nonlinear relationship between thermal conductivity and temperature. Additionally, a transient aerodynamic heating experiment simulation system is used to thermally test the same materials; the calculated and experimental results for the same materials are compared, which exhibit good consistency that demonstrates that accurate results can be obtained from the numerical computation using the relationship established from the experimentally measured conductivity and temperature.

Collapse criteria for high temperature ceramic lattice truss materials

Based on the temperature dependent behaviors of the Young's modulus and the strength of high temperature ceramics, temperature dependent failure characteristics of high temperature ceramic lattice truss materials were analyzed to build temperature-dependent failure theory. In compression, compression fracture and buckling are the competing failure modes. In shearing, tensile fracture and buckling are the competing failure modes. High temperature softening of the ceramic strut induces fatal buckling collapse for the lightweight lattice truss structure at ultra-high temperature. Collapse criteria under different planar stress states were built and are supported by high temperature experiments. Instructed by the criteria, collapse surfaces consisting of fracture surface and buckling surface were plotted and give helpful suggestions to design high temperature resistant as well as lightweight lattice truss ceramic composites.

Three-dimensional foam-like hexagonal boron nitride nanomaterials via atmospheric pressure chemical vapor deposition

Hexagonal boron nitride (h-BN) is a high temperature ceramic material with a graphite-like layered atomic arrangement and excellent basal-plane thermal conduction properties. Unlike graphite, however, h-BN is electrically insulating and possesses superior chemical stability, thereby making it attractive for many applications for which carbon allotropes are not suitable. In this work, freestanding three-dimensional foam-like h-BN nanomaterials tens of millimeters in size are realized by a low-cost atmospheric pressure chemical vapor deposition (APCVD) process. These three-dimensional foams were found to be ultralight with an effective density of 1.7 ± 0.6 mg/cm3. Strut wall thicknesses were observed to be 311 ± 82 nm, significantly thicker than reported in previous works using alternative CVD approaches. The samples were further analyzed using Raman spectroscopy, electron beam energy dispersive spectroscopy, and X-ray diffraction revealing the samples to exhibit characteristics consistent with h-BN. APCVD processes like the one presented here may provide a simple, scalable means of realizing ultralight hierarchical h-BN nanomaterials with tunable mechanical and thermal properties.

YAlO3:Ce3+ powders: Synthesis, characterization, thermoluminescence and optical studies

Yttrium aluminum perovskite (YAP) is a promising high temperature ceramic material, known for its mechanical, structural and optical properties. YAP’s also known as an ideal host material for solid-state lasers and phosphors. In this work, Ce3+ doped YAlO3 phosphors were synthesized by solid state reaction method, which is very suitable technique for large scale production. A prepared phosphor was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Photoluminescence spectra and Thermoluminescence (TL) glow curve study. The starting reagents used for sample preparation are Y2O3, Al2O3 and CeO2, boric acid used as a flux. Ratio of Y:Al was 1:1 which shows perovskite structure confirmed by the X-ray diffraction (XRD) study. The entire prepared sample was studied by PL excitation and emission spectra. Prominent peak at 446nm (blue emission) which shows broad emission spectra of photoluminescence. It proves that prepared phosphor can act as a single host for blue emission of light and can be used for display applications. Commission Internationale de I’Eclairage (CIE) techniques proves the blue emission of light (x=.148, y=.117). TL glow curve analysis of prepared phosphor shows the prominent peak at 189°C for the variable UV exposure time and high temperature peak shows the more stability and less fading in the prepared phosphor. Kinetic data of prepared phosphor were evaluated by peak shape method for variable UV exposure time (5–25min).