MATERIALS & DESIGN Vol. 8 No, 5 SEPTEMBER/OCTOBER 1987 271 High Strength & Modulus Filaments of Boron & Silicon Carbide M E Buck, Avco Specialty Materials, Textron, 2 Industrial Avenue, Lowell, MA 01851 USA Abstract The manufacture and application of boron and silicon …
A method for surface nitriding boron filaments to make the filaments useful as reinforcement agents in composite materials. The method involves initially forming a liquid boron oxide coating on the filament, for example, by heating the filament at temperatures of from about 560* C. to 800* C. in an oxidizing atmosphere and then converting the liquid oxide coating to a solid, continuous boron ...
The Czochralski process is a method of crystal growth used to obtain single crystals of semiconductors (e.g. silicon, germanium and gallium arsenide), metals (e.g. palladium, platinum, silver, gold), salts and synthetic gemstones.The process is named after Polish scientist Jan Czochralski, who invented the method in 1915 while investigating the crystallization rates of metals.
The primary use of elemental boron is as boron filaments with applications similar to carbon fibers in some high-strength materials. Boron is primarily used in chemical compounds. About half of all boron consumed globally is an additive in fiberglass for insulation and structural materials.
Silicon carbide-coated boron filaments have been produced both in a continuous and in a two-step process. The silicon carbide coating inhibits the oxidation of boron and also impedes the diffusion of boron into an aluminum or titanium matrix at elevated temperatures.
Because boron carbide has the highest fraction of boron of the three, it holds the highest potential. With this in mind, a hot filament chemical vapor deposition (HFCVD) system was designed and built in order to grow thin films of boron carbide onto n-type silicon substrates.
This patent describes a method for coating a substrate with a boron nitride film. It comprises: providing a substrate and a hot filament in a gas chamber; and introducing a borazine gas into the gas chamber so as to heat the borazine gas with the hot filament and deposit the boron nitride film on the substrate, wherein the hot filament is heated to a temperature of from about 1000[degrees] to ...
Nov 06, 1984· In the present invention, boron-based refractory material coatings are applied on silicon carbide filament by chemical vapor deposition. The silicon carbide filament may be produced by the method taught by DeBolt et al. The coatings are applied by passing the silicon carbide filament through a chemical vapor deposition reactor.
posites) the filament has to be protected by means of a thermo-mechan-ically and chemically compatible coating. During the last fifteen years 3 17* to develop new high temperature metal matrix composite systems, the compatibility of a number of coating materials for such filaments as tungsten, graphite, boron, silicon carbide, alumina, etc.,
Boron Silicon Filaments XiMiT. Abstract THE increasing use of boron filaments coated with boron and silicon carbide in composites has resulted in greater interest in the properties of these fibres . Interfacial Stability of Silicon Carbide Coated Boron .
Filament activated chemical vapor deposition of boron carbide coatings Sadanand V. Deshpande and Erdogan Gulari Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109 Stephen J. Harris and Anita M. Weiner Physical Chemistry, General Motors Research & Development Center, Warren, Michigan 48090-9055
Silicon carbide filaments are coated to protect them from attack by a titanium matrix material when incorporating them into a metal matrix composite. The coating method comprises coating the filaments firstly with a carbon layer and then with a titanium carbide or boride layer whose carbon or boron content decreases progressively from its interface with the carbon layer to its exterior surface.
Halide-Process Boron Filaments The halide-process boron filaments are so designated because they are pro- duced by the hydrogen reduction of a boron halide such as trichloride (BC13) or boron tribromi.de (BBr3) at the surface of a substrate wire (in this study, tungsten). borhood of …
A very special application is doping in Si MBE growth by using highly boron or phosphorus doped silicon filaments. Adjusting of the doping level is performed by changing the ratio of the flux rates between undoped silicon source and the boron / phosphorus doped silicon from the SUSI.
Silicon carbide filament is produced by overcoating a carbon monofilament core using continuous process vapor deposition. The deposition takes place by passing the carbon monofilament through a reactor into which gaseous sources of silicon and carbon are injected. At a deposition temperature of about 2370.degree. F., a deposit of fine grained beta crystals of silicon carbide are formed.
BORON FIBER Produced in single-filament reactors by Chemical Vapor Deposition (CVD), boron fiber exhibits a unique combination of High Strength, High Modulus and Large Diameter. Elemental boron is deposited on a fine tungsten wire substrate and produced in …
Continuous boron monofilaments (BF) and silicon carbide monofilaments (SCF) on substrates are among the main reinforcement fillers for modern high-strength and -modulus composites. ... Inorganic filaments on a substrate: boron and silicon carbide fibres. In: Kostikov V.I. (eds) Fibre Science and Technology. Soviet Advanced Composites Technology ...
The maximum boron concentration in the epitaxial film is about 2x10 19 cm-3 (during silicon sublimation some boron segregates on the surface of the silicon filament). For phosphorus doping the source material is P doped to about (3-4)x10 19 cm -3 .
Abstract. During the decade, 1960–1970, boron filament progressed from its position of a $5000 per pound laboratory curiosity to its present status of a production level reinforcement fiber exhibiting superior properties for advanced composite applications.
FUNDAMENTAL MECHANISMS OF TENSILE FRACTURE IN ALUMINUM SHEET UNIDIRECTIONALLY REINFORCED WITH BORON FILAMENT by Harvey Wayne Herring ... X. Strengths of 4.1 mils Diameter Silicon Carbide Coated Boron Filament Reclaimed from Commercially Fabricated Composite, ksi (Fig. 51) .. 114
Filament activated chemical vapor deposition of boron carbide coatings Sadanand V. Deshpande and Erdogan Gulari Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109 Stephen J. Harris and Anita M. Weiner Physical Chemistry, General Motors Research & Development Center, Warren, Michigan 48090-9055 ~Received 10 May 1994; accepted for publication 25 July 1994!
Boron filaments have high strength, yet are lightweight. The energy band gap of elemental boron is 1.50 to 1.56 eV, which is higher than that of silicon or germanium. Although elemental boron is not considered to be a poison, assimilation of boron compounds has a cumulative toxic effect.
Boron exists naturally as 19.78% 10B isotope and 80.22% 11B isotope. High-purity crystalline boron may be prepared by the vapor phase reduction of boron trichloride or tribromide with hydrogen on electically heated filaments. The impure or amorphous, boron, a brownish-black powder, can be obtained by heating the trioxide with magnesium powder.
Oct 12, 2016· Boron is a chemical element with symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it …
Boron fiber properties including, diameters, modulus, substrate,tensile strength,hardness,compression strength and thermal expansion rates.
Boron coated silicon carbide filaments; Boron coated silicon carbide filaments. Filament rein for cement impregnated with resin of thickenable composition based on an adduct of alkadiene polymers and acid anhydride Scnatore, G. (P... Download PDF . 137KB Sizes 6 Downloads 140 Views.
documented for technologically important filaments (except for c-axis sapphire). Experiments were conducted at the AFML over the past year to determine the mechanical and chemical properties of polycrystalline silicon carbide and single crystal sapphire filaments and are reported herein.
Nov 23, 1968· THE increasing use of boron filaments coated with boron and silicon carbide in composites has resulted in greater interest in the properties of these …
fraction of boron of the three, it holds the highest potential. With this in mind, a hot filament chemical vapor deposition (HFCVD) system was designed and built in order to grow thin films of boron carbide onto n-type silicon substrates. Deposition was accomplished via the thermal decomposition of B 2 H 6 [diborane] and CH 4 [methane].