Application of chemical vapor deposited yttria for the protection of silicon carbide fibers in a SiC/Ni3Al composite

1990 ◽  
Vol 5 (11) ◽  
pp. 2706-2717 ◽  
Author(s):  
D. J. Larkin ◽  
L. V. Interrante ◽  
A. Bose
Keyword(s):  
Silicon Carbide ◽  
Nickel Aluminide ◽  
Chemical Vapor ◽  
Degradation Process ◽  
Auger Spectroscopy ◽  
Silicon Carbide Fibers ◽  
Sic Fiber ◽  
Chemical Vapor Deposited ◽  
Volatile Products ◽  
Before And After

A CVD process has been developed for coating Textron-Avco SCS-6 SiC fiber with yttria. Both Y(fod)3·H2O and Y(thd)3 (fod = 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedionato; thd = 2,2,6,6-tetramethyl-3,5-heptanedionato) were examined as potential Y2O3 CVD precursors. Analysis of the deposits by Auger spectroscopy indicated significant F and C'incorporation in the case of Y(fod)3 · H2O whereas, under appropriate conditions, Y(thd)3 gave a deposit which was essentially free of C and other impurities. GCFTIR analysis of the volatile products of the CVD process indicated isobutylene, tetrafluoroethylene, 1,1-difluoroethylene, fluoroform, and fluoroethylene for Y(fod)3 · H2O and mainly isobutylene and propylene for Y(thd)3. The precursor Y(thd)3 was chosen to deposit 1–2 μm of yttria on short lengths of silicon carbide fibers. The coated fibers were then incorporated into a nickel aluminide (Ni3Al) matrix by reactive sintering, with yttria affording protection from the known SiC + 2Ni ⇉ Ni2Si + C degradation process. The SiC/Ni3Al composites, before and after annealing at 1000 °C for up to 100 h, were studied by using SEM and EMPA to determine the extent of reaction. With the exception of certain portions of the fibers that were inadequately coated with yttria, complete protection of the fibers was indicated.

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.

scholarly journals The Effect of Excess Carbon on the Crystallographic, Microstructural, and Mechanical Properties of CVD Silicon Carbide Fibers

2006 ◽  
Vol 982 ◽  
Author(s):  
James V Marzik ◽  
William J. Croft ◽  
Richard J. Staples ◽  
Warren J. MoberlyChan
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Silicon Carbide ◽  
Elastic Modulus ◽  
Chemical Vapor ◽  
High Strength ◽  
Excess Carbon ◽  
X Ray ◽  
Silicon Carbide Fibers ◽  
Sic Fiber

ABSTRACTSilicon carbide (SiC) fibers made by chemical vapor deposition (CVD) are of interest for organic, ceramic, and metal matrix composite materials due their high strength, high elastic modulus, and retention of mechanical properties at elevated processing and operating temperatures. The properties of SCS-6™ silicon carbide fibers, which are made by a commercial process and consist largely of stoichiometric SiC, were compared with an experimental carbon-rich CVD SiC fiber, to which excess carbon was added during the CVD process. The concentration, homogeneity, and distribution of carbon were measured using energy dispersive x-ray spectroscopy (SEM/EDS). The effect of excess carbon on the tensile strength, elastic modulus, and the crystallographic and microstructural properties of CVD silicon carbide fibers was investigated using tensile testing, x-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM).

Ultraprecision Surface Grinding of Chemical Vapor Deposited Silicon Carbide for X-Ray Mirrors Using Resinoid-Bonded Diamond Wheels

CIRP Annals ◽  
1999 ◽  
Vol 48 (1) ◽  
pp. 277-280 ◽  
Author(s):  
Y. Namba ◽  
H. Kobayashi ◽  
H. Suzuki ◽  
K. Yamashita ◽  
N. Taniguchi
Keyword(s):  
Silicon Carbide ◽  
Chemical Vapor ◽  
Surface Grinding ◽  
X Ray ◽  
Chemical Vapor Deposited

scholarly journals The structure of chemical vapor deposited silicon carbide

1977 ◽  
Vol 40 ◽  
pp. 57-72 ◽  
Author(s):  
J. Chin ◽  
P.K. Gantzel ◽  
R.G. Hudson
Keyword(s):  
Silicon Carbide ◽  
Chemical Vapor ◽  
Chemical Vapor Deposited

Hot wire chemical vapor deposited multiphase silicon carbide (SiC) thin films at various filament temperatures

2016 ◽  
Vol 27 (12) ◽  
pp. 12340-12350 ◽  
Author(s):  
Amit Pawbake ◽  
Vaishali Waman ◽  
Ravindra Waykar ◽  
Ashok Jadhavar ◽  
Ajinkya Bhorde ◽  
...  
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Chemical Vapor Deposited

Oxidation of PECVD SiC Deposited from Trimethylsilane

1998 ◽  
Vol 555 ◽  
Author(s):  
Peter A. DiFonzo ◽  
Mona Massuda ◽  
James T. Kelliher
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Oxidation Kinetics ◽  
Stoichiometric Composition ◽  
Chemical Vapor ◽  
Oxidation Rates ◽  
Chemical Vapor Deposited ◽  
Kinetics Of ◽  
Sic Films ◽  
Deposition Conditions

AbstractThe stoichiometric composition and oxidation rates ( wet or dry ) of plasma enhanced chemical vapor deposited (PECVD) silicon carbide (SiC) films are effected by the deposition conditions of trimethylsilane (3MS) and carrier gas. We report the oxidation kinetics of SiC thin films deposited in a modified commercial PECVD reactor. A standard horizontal atmospheric furnace in the temperature range of 925–1100°C was used in the oxidation. Oxidized films were measured optically by commercially available interferometer and ellipsometer tools in addition to mechanically using a commercially available profilometer. Activation energies of the parabolic rates were in the range of 20.93 to 335.26 kJ/mol.

Doping of phosphorus in chemical-vapor-deposited silicon carbide layers: A theoretical study

2005 ◽  
Vol 87 (21) ◽  
pp. 212114 ◽  
Author(s):  
T. Hornos ◽  
A. Gali ◽  
R. P. Devaty ◽  
W. J. Choyke
Keyword(s):  
Silicon Carbide ◽  
Theoretical Study ◽  
Chemical Vapor ◽  
Chemical Vapor Deposited
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