Promising ultra-high-temperature ceramic materials for aerospace applications

Some aspects of heat transfer upon the interaction between components with a sharp leading edge and high-enthalpy high-speed flow of dissociated air have been considered; some material characteristics, which should be primarily taken into account when prognosticating the behavior of materials that are promising for using as components of hypersonic flight vehicles, have been substantiated; specific features of the oxidation of materials based on zirconium and hafnium diborides have been touched briefly; the methods of increasing oxidation resistance of these materials that have been developed by various groups of researchers have been demonstrate; some works concerning the behavior of samples under the effect of high-enthalpy flows of dissociated air have been described, including those that simulate sharp leading domes and edges of wings of hypersonic flight vehicles.     

The raw-material base of adhesives and paint materials

The state of the national raw-material base for production of epoxy adhesive and paint materials and components of polyurethane compositions—isocyanates and polyesters—is presented.     

Functional ceramic materials database: an online resource for materials research

We present work on the creation of a ceramic materials database which contains data gleaned from literature data sets as well as new data obtained from combinatorial experiments on the London University Search Instrument. At the time of this writing, the database contains data related to two main groups of materials, mainly in the perovskite family. Permittivity measurements of electroceramic materials are the first area of interest, while ion diffusion measurements of oxygen ion conductors are the second. The nature of the database design does not restrict the type of measurements which can be stored; as the available data increase, the database may become a generic, publicly available ceramic materials resource.     

Characterization of metallic and ceramic high-temperature materials for energy systems

For the development of metallic and ceramic high temperature materials used, for example, in heat exchanger components, in turbine blades for stationary gas turbines, in ceramic industrial products and fusion reactor components, modern physico-chemical characterization methods are required. The formation stability of naturally formed protective scales is of prime importance in the successful application of metallic materials at high temperatures in aggressive atmospheres. For the characterization and investigation of the growth mechanisms of such surface scales, the main emphasis is placed on such modern spectroscopical methods as SIMS, SNMS, GDOS, EPMA and RBS. The morphology and composition of oxide scales have been investigated by imaging and diffraction techniques. The thermal and mechanical damage behaviour of high-temperature materials for application in fusion reactor components is of importance. Damage behaviour has been simulated by electron beam and laser irradiation experiments, especially by means of in situ techniques in a scanning electron microscope. By such techniques the material erosion, crack formation and crack propagation were studied for ceramic high temperature materials as a function of load parameters. The erosion and the crack formation processes are superim-posed by a redeposition of vaporized material and by thermally activated creep of the binder phases. The application potential for all methods discussed is outlined and available results are presented.     

Perspective high-temperature ceramic composite materials

The high-temperature glass-matrix and ceramic-matrix composites developed by the RIAM are overviewed. The distinctive properties of the developed composites are their high stability at temperatures above 1200°C in an oxidizing medium, high endurance and corrosion resistance, and low density and thermal expansion. Therefore, these composites are unique for production of heat-loaded units and parts of advanced engines. A characteristic feature of the SiC/SiC ceramic-matrix composite is its high resistance (by contrast to traditional monolithic ceramics) to thermocyclic loadings in the medium of fuel combustion products, which is due to its regulated and manageable structure.     

Electrochemistry of proton-conducting ceramic materials and cells

Journal of Solid State Electrochemistry -     

Properties of adhesives and adhesive materials used in aviation industry

Methods for developing adhesives and adhesive material used in the structures of almost all units of aviation machinery are described step by step. The properties of high-strength film-forming adhesives; adhesive prepregs; sandwich-type aluminum-polymer materials (SIALs); cold- and hot-setting adhesives intended for gluing metals, different nonmetallic materials, and combined joints; and self-adhesive film materials of ZPPK and FAS grades are given. It is also shown where and for which purposes these adhesives are applied.     

Microanalytical investigation of fibre-reinforced ceramic materials

Summary Microanalytical investigations have been made on samples of ceramic fibres (SiC fibres, (Nicalon) C fibre coated with TiN) and fibre-reinforced ceramics (SiC- and glass-matrices). High resolution Auger electron spectroscopy (HRAES), electron probe microanalysis (EPMA) and scanning electron microscopy were employed for these examinations. Analysis was best performed with HRAES on account of its lateral and depth resolution. Some of the problems involved in this technique are discussed e.g. electron beam effects. AES depth profiles of ceramic fibres are reported and compared with the surface analysis of fibres in the composites after being broken in situ.

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Mikroanalytische Untersuchungen faserverstärkter keramischer Werkstoffe

     

Computational evidence for stable inorganic fullerene-like structures of ceramic and semiconductor materials

Theoretical electronic structure techniques have become an indispensible and powerful means for predicting molecular properties and designing new materials. Based on a density functional approach and guided by geometric considerations we provide evidence for some specific inorganic fullerene-like cage molecules of ceramic and semiconductor materials which exhibit high energetic stability and point group symmetry as well as nearly perfect spherical shape.     

Novel carbon materials for thermal energy harvesting

To decrease the consumption of fossil fuels, research has been done on utilizing low grade heat, sourced from industrial waste streams. One promising thermoenergy conversion system is a thermogalvanic cell; it consists of two identical electrodes held at different temperatures that are placed in contact with a redox-based electrolyte [1, 2]. The temperature dependence of the direction of redox reactions allows power to be extracted from the cell [3, 4]. This study aims to increase the power conversion efficiency and reduce the cost of thermogalvanic cells by optimizing the electrolyte and utilizing a carbon based electromaterial, reduced graphene oxide, as electrodes. Thermal conductivity measurements of the K₃Fe(CN)₆/K₄Fe(CN)₆ solutions used, indicate that the thermal conductivity decreases from 0.591 to 0.547?W/m?K as the concentration is increased from 0.1 to 0.4?M. The lower thermal conductivity allowed a larger temperature gradient to be maintained in the cell. Increasing the electrolyte concentration also resulted in higher power densities, brought about by a decrease in the ohmic overpotential of the cell, which allowed higher values of short circuit current to be generated. The concentration of 0.4?M K₃Fe(CN)₆/K₄Fe(CN)₆ is optimal for thermal harvesting applications using R-GO electrodes due to the synergistic effect of the reduction in thermal flux across the cell and the enhancement of power output, on the overall power conversion efficiency. The maximum mass power density obtained using R-GO electrodes was 25.51?W/kg (three orders of magnitude higher than platinum) at a temperature difference of 60?°C and a K₃Fe(CN)₆/K₄Fe(CN)₆ concentration of 0.4?M.     

Zeolite-templated carbon materials for high-pressure hydrogen storage

Zeolite-templated carbon (ZTC) materials were synthesized, characterized, and evaluated as potential hydrogen storage materials between 77 and 298 K up to 30 MPa. Successful synthesis of high template fidelity ZTCs was confirmed by X-ray diffraction and nitrogen adsorption at 77 K; BET surface areas up to ~3600 m(2) g(-1) were achieved. Equilibrium hydrogen adsorption capacity in ZTCs is higher than all other materials studied, including superactivated carbon MSC-30. The ZTCs showed a maximum in Gibbs surface excess uptake of 28.6 mmol g(-1) (5.5 wt %) at 77 K, with hydrogen uptake capacity at 300 K linearly proportional to BET surface area: 2.3 mmol g(-1) (0.46 wt %) uptake per 1000 m(2) g(-1) at 30 MPa. This is the same trend as for other carbonaceous materials, implying that the nature of high-pressure adsorption in ZTCs is not unique despite their narrow microporosity and significantly lower skeletal densities. Isoexcess enthalpies of adsorption are calculated between 77 and 298 K and found to be 6.5-6.6 kJ mol(-1) in the Henry's law limit.     

Polypyrrole composites with carbon materials for supercapacitors

Supercapacitors fill the gap between batteries and conventional solid state and electrolytic capacitors. Polypyrrole (PPy) is a very important electrode material for supercapacitors. However, the repeated volume changes usually damage PPy structure and result in PPy poor stability during a long-term charging/discharging process. PPy/carbon material composites were prepared to overcome the defects of pure PPy electrodes, and significant enhancement for the specific capacitance, charging/discharging rate and electrodes stability was demonstrated thereafter. The development of composite electrodes based on PPy and carbon materials is reviewed in this paper.     

Microbe-derived carbon materials for electrical energy storage and conversion

Microbes are microscopic living organisms that surround us which include bacteria, archaea, most protozoa, and some fungi and algae. In recent years, microbes have been explored as novel precursors to synthesize carbon-based(nano)materials and as substrates or templates to produce carbon-containing(nano)composites. Being greener and more affordable, microbe-derived carbons(MDCs) offer good potential for energy applications. In this review, we describe the unique advantages of MDCs and outline the common procedures to prepare them. We also extensively discuss the energy applications of MDCs including their use as electrodes in supercapacitors and lithium-ion batteries, and as electrocatalysts for processes such as oxygen reduction, oxygen evolution, and hydrogen evolution reactions which are essential for fuel cell and water electrochemical splitting cells. Based on the literature trend and our group's expertise, we propose potential research directions for developing new types of MDCs. This review, therefore, provides the state-of-the-art of a new energy chemistry concept. We expect to stimulate future research on the applications of MDCs that may address energy and environmental challenges that our societies are facing.     

New developments in the field of reactive acrylic adhesives and sealing materials

The influence of oligomeric base on the properties of acrylic adhesives and sealants cured by radical mechanism is studied. New anaerobic materials on the basis of oligourethane(meth)acrylates (OUMs) are developed. It is shown that, by adjusting the OUM nature, it is possible to increase the heat and moisture stability of adhesive compositions. As a result of these works, UV-cured adhesive compositions, heat-cured adhesive for bonding untreated aluminum, and two-part adhesive compounds cured at both positive and negative temperatures are developed.     

Inorganic p-type semiconductors and carbon materials based hole transport materials for perovskite solar cells

Incorporation of proper inorganic p-type semiconductors as hole transport layer has great potential to increase long-term stability while maintaining high power conversion efficiency of perovskite solar cells with low material cost.     

Copolymers dispersions designed to shaping of ceramic materials

Journal of Thermal Analysis and Calorimetry - To study the effect of ionic liquids (ILs) of the microstructure on the surface of the coal, four ILs ([Emim][BF4], [Bmim][BF4], [Bmim][NO3], and...     

Functional carbon materials for high-performance Zn metal anodes

The realization of ‘‘carbon peak” and ‘‘carbon neutralization” highly depends on the efficient utilization of renewable energy sources. Exploring reliable and low-cost electrochemical energy storage systems is an ever-growing demand for renewable energy integration. Among available candidates, aqueous zinc-ion batteries(AZIBs) receive extensive researchers’ attention because of their material abundance, high capacity, high safety, and environmental friendliness. However, the irreversible issues ...     

Tempura-like carbon/carbon composite as advanced anode materials for K-ion batteries

Graphite as a promising anode candidate of K-ion batteries (KIBs) has been increasingly studied currently,but corresponding rate performance and cycling stabili...