Download or read book Microstructural Characterization of Reaction Formed Silicon Carbide Ceramics Materials Characterization written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-10-23 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microstructural characterization of two reaction-formed silicon carbide ceramics has been carried out by interference layering, plasma etching, and microscopy. These specimens contained free silicon and niobium disilicide as minor phases with silicon carbide as the major phase. In conventionally prepared samples, the niobium disilicide cannot be distinguished from silicon in optical micrographs. After interference layering, all phases are clearly distinguishable. Back scattered electron (BSE) imaging and energy dispersive spectrometry (EDS) confirmed the results obtained by interference layering. Plasma etching with CF4 plus 4% O2 selectively attacks silicon in these specimens. It is demonstrated that interference layering and plasma etching are very useful techniques in the phase identification and microstructural characterization of multiphase ceramic materials. Singh, M. and Leonhardt, T. A. Glenn Research Center ...
Download or read book Processing and Microstructural Characterization of Reaction formed Silicon Carbide RFSC and Computer Simulations X ray Diffraction and High Resolution Transmission Electron Microscopy of Stacking Faults in Beta SiC written by Vijay Vasant Pujar and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book I Processing and Microstructural Characterization of Reaction formed Silicon Carbide RFSC and written by Vijay Vasant Pujar and published by . This book was released on 1997 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization of Ceramics written by Ronald E. Loehman and published by Momentum Press. This book was released on 2010 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ceramics are, in a general definition, materials that consist of man-made, inorganic, non-metallic solid material - either existing in a crystalline state or non-crystalline state (i.e., glasses). Materials characterization techniques are used to ensure the structural and surface integrity of ceramics for their use in a wide variety of applications, from thermal resistance to advanced electronic and optical technologies like fiber optics to structural uses. This book presents those techniques along with views on future trends in ceramics processing and advanced characterization technologies particularly appropriate to ceramics materials. Readers will find more on: Ceramic Materials preparation routes, including powder preparation by solution techniques and gas-phase techniques Formation techniques for ceramic films and coatings, thick films and bulk ceramics A review of ceramic microstructure, reactions, phase behavior, mechanical properties and electronic and magnetic ceramics
Download or read book Nondestructive Ultrasonic Characterization of Armor Grade Silicon Carbide written by Andrew Richard Portune and published by . This book was released on 2011 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ceramic materials have traditionally been chosen for armor applications for their superior mechanical properties and low densities. At high strain rates seen during ballistic events, the behavior of these materials relies upon the total volumetric flaw concentration more so than any single anomalous flaw. In this context flaws can be defined as any microstructural feature which detriments the performance of the material, potentially including secondary phases, pores, or unreacted sintering additives. Predicting the performance of armor grade ceramic materials depends on knowledge of the absolute and relative concentration and size distribution of bulk heterogeneities. Ultrasound was chosen as a nondestructive technique for characterizing the microstructure of dense silicon carbide ceramics. Acoustic waves interact elastically with grains and inclusions in large sample volumes, and were well suited to determine concentration and size distribution variations for solid inclusions. Methodology was developed for rapid acquisition and analysis of attenuation coefficient spectra. Measurements were conducted at individual points and over large sample areas using a novel technique entitled scanning acoustic spectroscopy. Loss spectra were split into absorption and scattering dominant frequency regimes to simplify analysis. The primary absorption mechanism in polycrystalline silicon carbide was identified as thermoelastic in nature. Correlations between microstructural conditions and parameters within the absorption equation were established through study of commercial and custom engineered SiC materials. Nonlinear least squares regression analysis was used to estimate the size distributions of boron carbide and carbon inclusions within commercial SiC materials. This technique was shown to additionally be capable of approximating grain size distributions in engineered SiC materials which did not contain solid inclusions. Comparisons to results from electron microscopy exhibited favorable agreement between predicted and observed distributions. Developed techniques were applied to large sample areas using scanning acoustic spectroscopy to map variations in the size distribution and concentration of grains and solid inclusions within the bulk microstructure. The experiments performed in this thesis form the foundation of a novel characterization technique capable of mapping variations in sample composition which could be extended to a wide range of dense polycrystalline heterogeneous materials.
Download or read book Advanced Ceramics for Dentistry written by Saso Sturm and published by Elsevier Inc. Chapters. This book was released on 2013-09-05 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microstructure characterization of advanced ceramics involves qualitative and quantitative analysis of surface topography, porosity, crystal defects, and interfaces. The structure of the surface controls interaction of ceramics with its surroundings, such as adhesion, gas adsorption, and electron exchange, which play an important role in determining overall properties of a material. Pores in ceramic materials originate from incomplete densification during the sintering process. Their presence interferes with functional properties such as mechanical strength, optical transparency, electrical conductivity, and dielectric response. Crystal defects mostly form either as a result of imperfections during the crystal growth process or as a consequence of structural phase transitions. They generally affect most functional properties of materials. So-called extended defects are interfaces that are boundaries between two solids. The most widespread tools for characterization of ceramic microstructures are microscopic techniques involving optical microscopy, different types of electron microscopy, and various scanning-probe methods. This chapter gives a brief introduction of the features of ceramic microstructure and the corresponding techniques for characterizing them.
Download or read book Process Development for Silicon Carbide Based Structural Ceramics written by Edward E. Hucke and published by . This book was released on 1982 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this program is to develop a process for making shaped silicon carbide based ceramic materials with reduced microstructural flaw size by in situ reaction of silicon with fine, ultra-uniform pored carbon skeletons that are produced from liquid polymer solutions without particulate additions. Subsidiary objectives are: (1) delineation of the maximum section size producible while maintaining microstructural uniformity; (2) production of microstructures with characteristic features reduced from the current level of approximately 5-10 microns to the level of 1 micron or less; (3) characterization of microstructure, corresponding strength levels, and statistical uniformity; and (4) delineation of dimensional tolerances and surface finish that can be held during processing without finished machining. Very uniform and reproducible carbon skeletons have been produced and modified to provide for easy siliconization without extensive grain coarsening or formation of silicon veins and/or lakes have been achieved from 1 cm thick samples of carbon skeleton with particle size of 3.2 microns and pore size of 1.9 micrometers. The siliconized material has a maximum grain size of
Download or read book Characterization and Control of Interfaces for High Quality Advanced Materials written by Kevin Ewsuk and published by John Wiley & Sons. This book was released on 2012-04-11 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interface characterization and control are critical in the design and manufacture of high quality advanced materials, particularly, for nanomaterials. This proceedings features papers on interface science and technology that provide a unique and state-of-the art perspective on interface characterization and control. Articles from scientists and engineers from 11 different countries address interface control, high temperature interfaces, nanoparticle design, nanotechnology, suspension control, novel processing, particulate materials, microstructure, and hot gas cleaning. This unique volume will serve as a valuable reference for scientists and engineers interested in interfaces, particulate materials, and nanotechnology. Proceedings of the International Conference on ICCCI 2003, Kurashiki, Japan, 2003; Ceramic Transactions, Volume 146.
Download or read book Ceramic Microstructures written by Antoni P. Tomsia and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 841 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume, titled Proceedings of the International Materials Symposium on Ce ramic Microstructures: Control at the Atomic Level summarizes the progress that has been achieved during the past decade in understanding and controlling microstructures in ceram ics. A particular emphasis of the symposium, and therefore of this volume, is advances in the characterization, understanding, and control of micro structures at the atomic or near-atomic level. This symposium is the fourth in a series of meetings, held every ten years, devoted to ceramic microstructures. The inaugural meeting took place in 1966, and focussed on the analysis, significance, and production of microstructure; the symposium emphasized the need for, and importance of characterization in achieving a more complete understanding of the physical and chemical characteristics of ceramics. A consensus emerged at that meeting on the critical importance of characterization in achieving a more complete understanding of ceramic properties. That point of view became widely accepted in the ensuing decade. The second meeting took place in 1976 at a time of world-wide energy shortages and thus emphasized energy-related applications of ceramics, and more specifically, microstructure-property relationships of those materials. The third meeting, held in 1986, was devoted to the role that interfaces played both during processing, and in influencing the ultimate properties of single and polyphase ceramics, and ceramic-metal systems.
Download or read book Production and Characterization of Three dimensional Cellular Metal filled Ceramics written by Duncan Cree and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ceramic Microstructures 86 written by Joseph A. Pask and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Proceedings of the International Materials Symposium on Ceramic Microstructures '86: Role of Interfaces presents a comprehensive coverage of the past decade's advances in ceramic science and technology related to microstructures. The term microstructure is used in the broad sense and is synonymous with char~cter. Character is defined as a complete detailed description of chemical and physical characteristics of a material. This symposium is the third in a series, held every ten years, on ceramic microstructures. The first symposium, in 1966, had as a subtitle "Their Analysis, Significance and Production" and emphasized the need and importance of characterization in order to fully understand the chemical and physical properties of materials. The second Symposium, in 1976, placed emphasis on the exploration of characters most suited and needed for "Energy-Related Applications." By the time of that conference, the sequence of processing--characterization--properties was fully accepted. It was recognized that characterization was the basis of materials science; the objective of processing was to produce a desired character that was considered necessary to realize a given property or behavior. To further emphasize the importance of character, the symposium dealt primarily with the property/character coupling.
Download or read book Silicon Carbide Ceramics written by S. Somiya and published by Springer Science & Business Media. This book was released on 1991-08-31 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silicon carbides have major industrial uses as high temperature structural ceramic materials. These two volumes are translated from the Japanese and provide a comprehensive account of the seminal work going on in Japan.
Download or read book Mechanical Properties and Microstructure of Biomorphic Silicon Carbide Ceramics Fabricated from Wood Precursors written by Nasa Technical Reports Server (Ntrs) and published by BiblioGov. This book was released on 2013-08 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silicon carbide based, environment friendly, biomorphic ceramics have been fabricated by the pyrolysis and infiltration of natural wood (maple and mahogany) precursors. This technology provides an eco-friendly route to advanced ceramic materials. These biomorphic silicon carbide ceramics have tailorable properties and behave like silicon carbide based materials manufactured by conventional approaches. The elastic moduli and fracture toughness of biomorphic ceramics strongly depend on the properties of starting wood preforms and the degree of molten silicon infiltration. Mechanical properties of silicon carbide ceramics fabricated from maple wood precursors indicate the flexural strengths of 3441+/-58 MPa at room temperature and 230136 MPa at 1350C. Room temperature fracture toughness of the maple based material is 2.6 +/- 0.2 MPa(square root of)m while the mahogany precursor derived ceramics show a fracture toughness of 2.0 +/- 0.2 Mpa(square root of)m. The fracture toughness and the strength increase as the density of final material increases. Fractographic characterization indicates the failure origins to be pores and chipped pockets of silicon.
Download or read book written by סולומון בן אברהם אדרת and published by . This book was released on 1972 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ceramography written by Richard E. Chinn and published by ASM International. This book was released on 2002 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Ceramography" provides detailed instructions on how to saw, mount, grind, polish, etch, examine, interpret and measure ceramic microstructures. This new book includes an atlas of ceramic microstructures, quantitative microstructural example problems with solutions, properties and data tables specific to ceramic microstructures, more than 100 original photographs and illustrations, and numerous practical tips and tricks of the trade. An excellent reference guide for technicians in quality control and R&D, process engineers in ceramic manufacturing, and their counterparts in engineering firms, national laboratories, research institutes, and universities.
Download or read book Characterization of Ceramics and Intermetallics Fabricated by Self propagating High temperature Synthesis written by and published by . This book was released on 1989 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microhardness Friction and Wear of SiC and Si3N4 Materials as a Function of Load Temperature and Environment written by M. G. S. Naylor and published by . This book was released on 1981 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasticity and fracture processes in engineering ceramics based on silicon carbide, silicon nitride, a sialon and boron carbide have been investigated as a function of temperature (in the range 25 - 1000 C) using indentation microhardness techniques. The effects of specimen microstructure on indentation processes were determined by using materials formed by a wide range of fabrication routes (sintering, hot-pressing, reaction-bonding and pyrolytic deposition) and comparison was made with the behaviour of single crystals (SiC and Si). Microstructural characterization was carried out by light microscopy, electron-optical and X-ray techniques. The variation of Vickers and, in some cases, Knoop microhardness with temperature was measured, and deformation structures around indentations were examined optically and by scanning electron microscopy. Indentation plasticity in silicon carbide was further investigated by measuring Knoop hardness anisotropy on basal and non-basal faces of single crystal SiC at various temperatures. The effect of dopant on hardness was investigated for Si and SiC.
