Design and optimization of silicon carbide mirrors for the Canadian Large Optical Telescope (LOT)

2017 ◽  
Author(s):  
Joeleff Fitzsimmons
Keyword(s):  
Silicon Carbide ◽  
Optical Telescope ◽  
Design And Optimization

Busbar Design and Optimization for Voltage Overshoot Mitigation of a Silicon Carbide High-Power Three-Phase T-Type Inverter

2021 ◽  
Vol 36 (1) ◽  
pp. 204-214 ◽  
Author(s):  
Zhongjing Wang ◽  
Yuheng Wu ◽  
Mohammad Hazzaz Mahmud ◽  
Zhao Yuan ◽  
Yue Zhao ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
High Power ◽  
Design And Optimization ◽  
Three Phase

scholarly journals Complex elements of aerospace equipment from reaction silicon carbide ceramics

2020 ◽  
Vol 64 (6) ◽  
pp. 730-738
Author(s):  
A. Ph. Ilyushchenko ◽  
L. N. Dyachkova ◽  
V. A. Osipov
Keyword(s):  
Silicon Carbide ◽  
Braze Alloy ◽  
The Body ◽  
Carbide Powder ◽  
Complex Profile ◽  
Optical Telescope ◽  
Profile Element ◽  
Carbide Ceramics ◽  
Silicon Carbide Ceramics ◽  
Silicon Carbide Powder

The results of studying the process of obtaining complex-profile elements of the substrate of mirrors of optical telescopes from reaction-sintered silicon carbide ceramics are presented. It is shown that the strength of silicon carbide ceramics depends on the dispersion of the silicon carbide powder and on the temperature of reaction sintering. An increase in the sintering temperature from 1500 to 1650 °C leads to an increase in strength by 60 MPa, and to 1800 °C – to a decrease in strength by 40 MPa. An increase in strength is explained by a decrease in free silicon and an increase in the content of secondary silicon carbide, a decrease in strength is explained by an increase in the size of carbide grains. The study of the influence of the modes of soldering of hexagonal elements to obtain a complex-profile element of the substrate of the mirror of an optical telescope on the strength of the soldered seam showed that the introduction of silicon carbide powder 7 μm in size and amorphous boron in an amount of 6 % into the solder composition based on silicon carbide has a positive effect on the strength of the soldered seam. Tests of the brazed specimens at three-point bending showed that fracture occurs along the body of the specimens being brazed, and not the brazed seam. The structure of the brazed joint depends on the composition of the braze alloy and the gap between the samples to be brazed.

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

Microstructural Evaluation of Silicon Carbide Whisker Reinforced Alumina Fabricated with Carbon-Coated Whiskers

1991 ◽  
Vol 49 ◽  
pp. 920-921
Author(s):  
K. B. Alexander ◽  
P. F. Becher
Keyword(s):  
Silicon Carbide ◽  
High Resolution Electron Microscopy ◽  
Ceramic Composites ◽  
Interface Debonding ◽  
Resolution Electron ◽  
Microstructural Evaluation ◽  
Carbon Coated ◽  
Electron Energy Loss ◽  
Interfacial Films ◽  
Debonding Process

The presence of interfacial films at the whisker-matrix interface can significantly influence the fracture toughness of ceramic composites. The film may alter the interface debonding process though changes in either the interfacial fracture energy or the residual stress at the interface. In addition, the films may affect the whisker pullout process through the frictional sliding coefficients or the extent of mechanical interlocking of the interface due to the whisker surface topography.Composites containing ACMC silicon carbide whiskers (SiCw) which had been coated with 5-10 nm of carbon and Tokai whiskers coated with 2 nm of carbon have been examined. High resolution electron microscopy (HREM) images of the interface were obtained with a JEOL 4000EX electron microscope. The whisker geometry used for HREM imaging is described in Reference 2. High spatial resolution (< 2-nm-diameter probe) parallel-collection electron energy loss spectroscopy (PEELS) measurements were obtained with a Philips EM400T/FEG microscope equipped with a Gatan Model 666 spectrometer.

TEM of grain growth and phase transformations during creep of SCS-6 silicon carbide fibers

1995 ◽  
Vol 53 ◽  
pp. 350-351
Author(s):  
L. A. Giannuzzi ◽  
C. A. Lewinsohn ◽  
C. E. Bakis ◽  
R. E. Tressler
Keyword(s):  
Silicon Carbide ◽  
Creep Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Primary Creep ◽  
Excess Carbon ◽  
Silicon Carbide Fibers ◽  
Sic Fiber ◽  
Carbon Core ◽  
Grain Width

The SCS-6 SiC fiber is a 142 μm diameter fiber consisting of four distinct regions of βSiC. These SiC regions vary in excess carbon content ranging from 10 a/o down to 5 a/o in the SiC1 through SiC3 region. The SiC4 region is stoichiometric. The SiC sub-grains in all regions grow radially outward from the carbon core of the fiber during the chemical vapor deposition processing of these fibers. In general, the sub-grain width changes from 50nm to 250nm while maintaining an aspect ratio of ~10:1 from the SiC1 through the SiC4 regions. In addition, the SiC shows a <110> texture, i.e., the {111} planes lie ±15° along the fiber axes. Previous has shown that the SCS-6 fiber (as well as the SCS-9 and the developmental SCS-50 μm fiber) undergoes primary creep (i.e., the creep rate constantly decreases as a function of time) throughout the lifetime of the creep test.

Design and Optimization of a Novel Strategy for the Local Treatment of Helicobacter pylori Infections

2020 ◽  
Author(s):  
Taddese Mekonnen Ambay ◽  
Philipp Schick ◽  
Michael Grimm ◽  
Maximilian Sager ◽  
Felix Schneider ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Local Treatment ◽  
Design And Optimization ◽  
Novel Strategy

LASER INDUCED ORDERING AND DEFECTS IN ION-IMPLANTED HEXAGONAL SILICON CARBIDE

1980 ◽  
Vol 41 (C4) ◽  
pp. C4-111-C4-112 ◽  
Author(s):  
V. V. Makarov ◽  
T. Tuomi ◽  
K. Naukkarinen ◽  
M. Luomajärvi ◽  
M. Riihonen
Keyword(s):  
Silicon Carbide ◽  
Ion Implanted
Sign in / Sign up

Export Citation Format

Share Document