Structure and nanostructure in ionic liquids.

Design, preparation and properties of non-oxide CMCs for application in engines and nuclear reactors: an overview

The present invention provides nanometer-sized diameter silica fibers that exhibit high diameter uniformity and surface smoothness. The silica fibers can have diameters in a range of a about 20 nm to about 1000 nm. An exemplary method according to one embodiment of the invention for generating such fibers utilizes a two-step process in which in an initial step a micrometer sized diameter silica preform fiber is generated, and in a second step, the silica preform is drawn while coupled to a support element to form a nanometer sized diameter silica fiber. The portion of the support element to which the preform is coupled is maintained at a temperature suitable for drawing the nansized fiber, and is preferably controlled to exhibit a temporally stable temperature profile.

/pdf/subwavelength-diameter-silica-wires-for-low-loss-optical-2e6789b5ae.pdf

Subwavelength-diameter silica wires for low-loss optical waveguiding

Progress in material selection for solid oxide fuel cell technology: A review

Humankind's aerospace aspirations are placing unprecedented demands on vehicle propulsion systems. Advanced structural ceramics are playing a key role in addressing these challenges.

Advanced structural ceramics in aerospace propulsion.

Introduction. Commercial Glasses: Vitreous Silica. Commerical Glasses. Thermodynamic and Thermal Properties: Density. Surface Tension. Coefficient of Thermal Expansion. Heat Capacity. Thermal Conductivity. Mechanical Properties: Viscosity. Elastic Properties. Microhardness. Strength. Electrical and Transport Properties: Electrical Conductivity. Dielectric Properties. Ionic Diffusion. Other Properties: Refractive Index and Dispersion. Solubility, Permeability, and Diffusion of Gases in Glass. Chemical Durability. Estimation of Properties. Appendices. Systems Index. Subject Index.

Handbook of glass properties

Rare earth silicates have been investigated to evaluate their potential as an advanced environmental barrier coating (EBC) having higher temperature capability than current EBCs. Volatility data in high steam environments indicate that rare earth monosilicates (RE 2 SiO 5 ; RE: rare earth element) have lower volatility than the current barium strontium aluminum silicate (BSAS) EBC top coat in combustion environments. Rare earth silicates also exhibit superior chemical compatibility compared to BSAS. The superior chemical compatibility and low volatility are key attributes to achieve higher temperature capability. The chemical compatibility is especially critical for EBCs on Si 3 N 4 because of the high chemical reactivity of some of the oxide additives in Si 3 N 4 . In simulated combustion environments, EBCs with a rare earth monosilicate top coat exhibit superior temperature capability and durability compared to the current state-of-the art EBCs with a BSAS top coat.

Rare earth silicate environmental barrier coatings for SiC/SiC composites and Si3N4 ceramics

Preface Ceramic Fibers Oxide Fibers A R Bunsell Non-oxide (Silicon Carbide) Fibers J A DiCarlo and H-M Yun Non-oxide/Non-oxide Composites Chemical Vapor Infiltrated SiC/SiC Composites (CVI SiC/SiC) J Lamon SiC/SiC Composites for 1200 C and Above J A DiCarlo, H-M Yun, G N Morscher, and R T Bhatt Silicon Melt Infiltrated Ceramic Composites (HiPerCompTM) G S Corman and K L Luthra Carbon Fibre Reinforced Silicon Carbide Composites (C/SiC, C/C-SiC) W Krenkel Silicon Carbide Fiber-Reinforced Silicon Nitride Composites R T Bhatt MoSi2-Base Composites M G Hebsur Ultra High Temperature Ceramic Composites M J Gasch, D T Ellerby and S M Johnson Non-oxide/Oxide Composites SiC Fiber-Reinforced Celsian Composites N P Bansal In Situ Reinforced Silicon Nitride - Barium Aluminosilicate Composite K W White, F Yu and Y Fang Silicon Carbide and Oxide Fiber Reinforced Alumina Matrix Composites Fabricated Via Directed Metal Oxidation A S Fareed SiC Whisker Reinforced Alumina T Tiegs Mullite-SiC Whisker and Mullite-ZrO2-SiC Whisker Composites R Ruh NextelTM 312/Silicon Oxycarbide Ceramic Composites S T Gonczy and J G Sikonia Oxide/Oxide Composites Oxide-Oxide Composites K A Keller, G Jefferson and R J Kerans WHIPOX All Oxide Ceramic Matrix Composites M Schmucker and H Schneider Alumina-Reinforced Zirconia Composites S R Choi and N P Bansal Glass andGlass-Ceramic Composites Continuous Fibre Reinforced Glass and Glass-Ceramic Matrix Composites AR Boccaccini Dispersion-Reinforced Glass and Glass-Ceramic Matrix Composites J A Roether and A R Boccaccini Glass Containing Composite Materials: Alternative Reinforcement Concepts AR Boccaccini

Handbook of Ceramic Composites

Current state-of-the-art environmental barrier coatings (EBCs) for Si-based ceramics consist of three layers: a silicon bond coat, an intermediate mullite (3Al2O3-2SiO2) or mullite + BSAS (1-xBaO-xSrO-Al2O3-2SiO2) layer, and a BSAS top coat. Areas of concern for long-term durability are environmental durability, chemical compatibility, silica volatility, phase stability, and thermal conductivity. Variants of this family of EBCs were applied to monolithic SiC and melt infiltrated SiC/SiC composites. Reaction between BSAS and silica results in low melting (approx. 1300 C) glasses at T > 1400 C, which can cause the spallation of the EBC. At temperatures greater than 1400 C, the BSAS top coat also degrades by formation of a porous structure, and it suffers significant recession via silica volatilization in water vapor-containing atmospheres. All of these degradation mechanisms can be EBC life-limiting factors. BSAS undergoes a very sluggish phase transformation (hexagonal celsian to monoclinic celsian), the implications of which are not fully understood at this point. There was evidence of rapid sintering at temperatures as low as 1300 C, as inferred from the sharp increase in thermal conductivity.

/pdf/upper-temperature-limit-of-environmental-barrier-coatings-svtgf4isg7.pdf

Upper Temperature Limit of Environmental Barrier Coatings Based on Mullite and BSAS

The present work provides selected data with value judgements for an additional set of 107 salt systems of interest as candidate materials for thermal energy storage sub-systems, for electrochemical energy storage systems, and in electrochemical aluminum production The physical properties assessed are: melting points; phase diagrams; eutectic compositions; density; surface tension; viscosity; electrical conductivity; diffusion constants for ions; heat of fusion; heat capacity; volume change on fusion; vapor pressure; thermal conductivity (liquid and solid); and cryoscopic constant The status of corrosion studies in the form of annotated bibliographic summaries, and salient observations on safety and hazards are also reported A summarizing series of tables is provided as index to the data-gaps status for this set of candidate materials

Narottam P. Bansal

Papers

Handbook of glass properties

Rare earth silicate environmental barrier coatings for SiC/SiC composites and Si3N4 ceramics

Handbook of Ceramic Composites

Upper Temperature Limit of Environmental Barrier Coatings Based on Mullite and BSAS

Physical properties data compilations relevant to energy storage. ii: molten salts: data on single and multi-component salt systems