Download or read book Characterisation of Polycrystalline Silicon Carbide by Scanning and Transmission Electron Microscopy written by Atomic Energy of Canada Limited and published by . This book was released on 1970 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanical Chemical and Microstructural Characterization of Monazite Coated Silicon Carbide Fibers written by Narottam P. Bansal and published by . This book was released on 2000 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tensile strengths of as-received Hi-Nicalon and Sylramic fibers and those having monazite surface coatings, deposited by atmospheric pressure chemical vapor deposition, were measured at room temperature and the Weibull statistical parameters determined. The average tensile strengths of uncoated Hi-Nicalon and Sylramic fibers were 3.19 +/- 0.73 and 2.78 +/- 0.53 GPa with a Weibull modulus of 5.41 and 5.52, respectively. The monazite-coated Hi-Nicalon and Sylramic fibers showed strength loss of approx. 10 and 15 percent, respectively, compared with the as-received fibers. The elemental compositions of the fibers and the coatings were analyzed using scanning Auger microprobe and energy dispersive X-ray spectroscopy. The LaPO4 coating on Hi-Nicalon fibers was approximately stoichiometric and about 50 nm thick. The coating on the Sylramic fibers extended to a depth of about 100 to 150 nm. The coating may have been stoichiometric LaPO4 in the first 30 to 40 nm of the layer. However, the surface roughness of Sylramic fiber made this profile somewhat difficult to interpret. Microstructural analyses of the fibers and the coatings were done by scanning electron microscopy, transmission electron microscopy, and selected area electron diffraction.

Download or read book Mechanical Chemical and Microstructural Characterization of Monazite Coated Silicon Carbide Fibers written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-09-27 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tensile strengths of as-received Hi-Nicalon and Sylramic fibers and those having monazite surface coatings, deposited by atmospheric pressure chemical vapor deposition, were measured at room temperature and the Weibull statistical parameters determined. The average tensile strengths of uncoated Hi-Nicalon and Sylramic fibers were 3.19 +/- 0.73 and 2.78 +/- 0.53 GPa with a Weibull modulus of 5.41 and 5.52, respectively. The monazite-coated Hi-Nicalon and Sylramic fibers showed strength loss of approx. 10 and 15 percent, respectively, compared with the as-received fibers. The elemental compositions of the fibers and the coatings were analyzed using scanning Auger microprobe and energy dispersive X-ray spectroscopy. The LaPO4 coating on Hi-Nicalon fibers was approximately stoichiometric and about 50 nm thick. The coating on the Sylramic fibers extended to a depth of about 100 to 150 nm. The coating may have been stoichiometric LaPO4 in the first 30 to 40 nm of the layer. However, the surface roughness of Sylramic fiber made this profile somewhat difficult to interpret. Microstructural analyses of the fibers and the coatings were done by scanning electron microscopy, transmission electron microscopy, and selected area electron diffraction. Hi-Nicalon fiber consists of fine beta-SiC nanocrystals ranging in size from 1 to 30 mn embedded in an amorphous matrix. Sylramic is a polycrystalline stoichiometric silicon carbide fiber consisting of submicron beta-SiC crystallites ranging from 100 to 300 nm. Small amount of TiB2 nanocrystallites (approx. 50 nm) are also present. The LaPO4 coating on Hi-Nicalon fibers consisted of a chain of peanut shape particles having monazite-(La) structure. The coating on Sylramic fibers consisted of two layers. The inner layer was a chain of peanut shape particles having monazite-(La) structure. The outer layer was comprised of much smaller particles with a microcrystalline structure. Bansal, N. P. and Wheeler, D. R. and Chen, Y. L. Glenn Rese

Download or read book Structural Characterization of Hard Materials by Transmission Electron Microscopy TEM written by Chun-sŏk Park and published by . This book was released on 2008 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Proceedings of The Twenty eighth Annual Meeting Houston Texas October 5 6 7 and 8 1970 written by Electron Microscopy Society of America and published by . This book was released on 1970 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Surface Characterization and Manipulation of Silicon Nitride and Silicon Carbide Powders written by Yves Boiteux and published by . This book was released on 1986 with total page 182 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 Polysilicon Films by Raman Spectroscopy and Transmission Electron Microscopy written by and published by . This book was released on 1993 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Samples of chemically-vapor-deposited micrometer and sub-micrometer-thick films of polysilicon were analyzed by transmission electron microscopy (TEM) in cross-section and by Raman spectroscopy with illumination at their surface. TEM and Raman spectroscopy both find varying amounts of polycrystalline and amorphous silicon in the wafers. Raman spectra obtained using blue, green and red excitation wavelengths to vary the Raman sampling depth are compared with TEM cross-sections of these films. Films showing crystalline columnar structures in their TEM micrographs have Raman spectra with a band near 497 cm−1 in addition to the dominant polycrystalline silicon band (521 cm−1). The TEM micrographs of these films have numerous faulted regions and fringes indicative of nanometer-scale silicon structures, which are believed to correspond to the 497cm−1 Raman band.

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 Characterization of Process related Defects in Silicon Carbide by Electron Microscopy written by Per O. Å Persson and published by . This book was released on 2001 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Growth and Characterization of Silicon Carbide on AIN Si written by John H. Goldsmith and published by . This book was released on 2008 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: Epitaxial silicon carbide (SiC) was grown using chemical vapor deposition (CVD) on silicon substrates with Aluminum Nitride (AIN) buffer layers. Subsequent films where characterized by Raman Spectroscopy, Scanning Electron microscopy, Atomic Force microscopy, and X-ray diffraction. There is a large lattice mismatch between SiC and silicon, by introducing an AIN buffer layer, which has a close lattice match to SiC, the strain on the film is reduced and hence the density of defects is reduced. Trimethylsilane, an relatively inert alternative to silane, was used as the precursor providing both the required silicon and carbon atoms.

Download or read book Progress in SOI Structures and Devices Operating at Extreme Conditions written by Francis Balestra and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 349 pages. Available in PDF, EPUB and Kindle. Book excerpt: A review of the electrical properties, performance and physical mechanisms of the main silicon-on-insulator (SOI) materials and devices. Particular attention is paid to the reliability of SOI structures operating in harsh conditions. The first part of the book deals with material technology and describes the SIMOX and ELTRAN technologies, the smart-cut technique, SiCOI structures and MBE growth. The second part covers reliability of devices operating under extreme conditions, with an examination of low and high temperature operation of deep submicron MOSFETs and novel SOI technologies and circuits, SOI in harsh environments and the properties of the buried oxide. The third part deals with the characterization of advanced SOI materials and devices, covering laser-recrystallized SOI layers, ultrashort SOI MOSFETs and nanostructures, gated diodes and SOI devices produced by a variety of techniques. The last part reviews future prospects for SOI structures, analyzing wafer bonding techniques, applications of oxidized porous silicon, semi-insulating silicon materials, self-organization of silicon dots and wires on SOI and some new physical phenomena.

Download or read book Proceedings Annual Meeting Electron Microscopy Society of America written by Electron Microscopy Society of America and published by . This book was released on 1970 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamentals of Silicon Carbide Technology written by Tsunenobu Kimoto and published by John Wiley & Sons. This book was released on 2014-09-23 with total page 565 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive introduction and up-to-date reference to SiC power semiconductor devices covering topics from material properties to applications Based on a number of breakthroughs in SiC material science and fabrication technology in the 1980s and 1990s, the first SiC Schottky barrier diodes (SBDs) were released as commercial products in 2001. The SiC SBD market has grown significantly since that time, and SBDs are now used in a variety of power systems, particularly switch-mode power supplies and motor controls. SiC power MOSFETs entered commercial production in 2011, providing rugged, high-efficiency switches for high-frequency power systems. In this wide-ranging book, the authors draw on their considerable experience to present both an introduction to SiC materials, devices, and applications and an in-depth reference for scientists and engineers working in this fast-moving field. Fundamentals of Silicon Carbide Technology covers basic properties of SiC materials, processing technology, theory and analysis of practical devices, and an overview of the most important systems applications. Specifically included are: A complete discussion of SiC material properties, bulk crystal growth, epitaxial growth, device fabrication technology, and characterization techniques. Device physics and operating equations for Schottky diodes, pin diodes, JBS/MPS diodes, JFETs, MOSFETs, BJTs, IGBTs, and thyristors. A survey of power electronics applications, including switch-mode power supplies, motor drives, power converters for electric vehicles, and converters for renewable energy sources. Coverage of special applications, including microwave devices, high-temperature electronics, and rugged sensors. Fully illustrated throughout, the text is written by recognized experts with over 45 years of combined experience in SiC research and development. This book is intended for graduate students and researchers in crystal growth, material science, and semiconductor device technology. The book is also useful for design engineers, application engineers, and product managers in areas such as power supplies, converter and inverter design, electric vehicle technology, high-temperature electronics, sensors, and smart grid technology.

Download or read book Microstructural Chemical and Mechanical Characterization of Polymer Derived Hi Nicalon Fibers with Surface Coatings written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-05 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Room temperature tensile strengths of as-received Hi-Nicalon fibers and those having BN/SiC, p-BN/SiC, and p-B(Si)N/SiC surface coatings, deposited by chemical vapor deposition, were measured using an average fiber diameter of 13.5 microns. The Weibull statistical parameters were determined for each fiber. The average tensile strength of uncoated Hi-Nicalon on was 3.19 +/- 0.73 GPa with a Weibull modulus of 5.41. Strength of fibers coated with BN/SiC did not change. However, coat with p-BN/SiC and p-B(Si)N/SiC surface layers showed strength loss of approx. 10 and 35 percent, respectively, compared with as-received fibers. The elemental compositions of the fibers and the coatings were analyzed using scanning Auger microprobe and energy dispersive x-ray spectroscopy. The BN coating was contaminated with a large concentration of carbon and some oxygen. In contrast, p-BN, p-B(Si)N, and SiC coatings did not show any contamination. Microstructural analyses of the fibers and the coatings were done by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction. Hi-Nicalon fiber consists of the P-SIC nanocrystals ranging in size from 1 to 30 nm embedded in an amorphous matrix. TEM analysis of the BN coating revealed four distinct layers with turbostatic structure. The p-BN layer was turbostratic and showed considerable preferred orientation. The p-B(Si)N was glassy and the silicon and boron were uniformly distributed. The silicon carbide coating was polycrystalline with a columnar structure along the growth direction. The p-B(Si)N/SiC coatings were more uniform, less defective and of better quality than the BN/SiC or the p-BN/SiC coatings. Bansal, Narottam P. and Chen, Yuan L. Glenn Research Center RTOP 523-21-31...

Download or read book Thermal Modification of Microstructures and Grain Boundaries in Silicon Carbide written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polycrystalline SiC samples hot-pressed with aluminum, boron, and carbon sintering additions (ABC-SiC) were characterized using transmission electron microscopy. The study focused on the effects of high temperature treatment on microstructure.