John A. Hanigofsky

Georgia Institute of Technology

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W. J. Lackey

Georgia Institute of Technology

E. Kent Barefield

Georgia Institute of Technology

D. N. Hill

Georgia Institute of Technology

G. B. Freeman

Analysis Group (United States)

T. S. Moss

University of Houston

David F. O’Brien

Internet Society

M. Shapiro

Mayo Clinic in Arizona

Karren L. More

Oak Ridge National Laboratory

Woo Y. Lee

Stevens Institute of Technology

Elizabeth Ann Judson

Georgia Institute of Technology

Cooperative Institutions

Georgia Institute of Technology

Oak Ridge National Laboratory

American Ceramic Society

Georgia Tech Research Institute

IBM (United States)

University of Tennessee at Knoxville

Technology Assessment and Transfer (United States)

Wright-Patterson Air Force Base

University of Arizona

University of Rochester

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Composition and Microstructure of Chemically Vapor‐Deposited Boron Nitride, Aluminum Nitride, and Boron Nitride + Aluminum Nitride Composites

Journal of the American Ceramic Society (1991)

John A. Hanigofsky Karren L. More W. J. Lackey Woo Y. Lee G. B. Freeman

The composition and microstructure of dispersed‐phase ceramic composites containing BN and AIN as well as BN and AIN single‐phase ceramics prepared by chemical vapor deposition have been characterized using X‐ray diffraction, scanning electron microscopy, electron microprobe, and transmission electron microscopy techniques. Under certain processing conditions, the codeposited coating microstructure consists of small single‐crystal AIN fibers (whiskers) surrounded by a turbostratic BN matrix. Other processing conditions resulted in single‐phase films of AIN with a fibrous structure. The compositions of the codeposits range from 2 to 50 mol% BN, 50 to 80 mol% AIN with 7% to 25% oxygen impurity as determined by electron microprobe analysis.

Microprobe

10.1111/j.1151-2916.1991.tb06879.x

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Citations (23)

Preparation of superconducting wire by deposition of YBa2Cu3O(x) onto fibers

W. J. Lackey John A. Hanigofsky M. J. Shapiro W. B. Carter D. N. Hill

Deposition

Superconducting wire

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Citations (1)

Ceramic composite combustor cans for expendable turbine engines. Final report, 29 April 1993-15 February 1994

L. Fehrenbacher John A. Hanigofsky

Ceramic matrix composite fabrication by microwave assisted chemical vapor infiltration (MWCVI) has been demonstrated as a feasible, faster, and more economical technique as compared to conventional CVI. Two deposition systems, carbon and silicon carbide, were investigated using this processing technique. Densification rates over an order of magnitude higher have been achieved on small cylindrical Nicalon fiber preforms. Economic forecasts based on previous SiC deposition and this Phase I work shows a significant improvement in part cost as compared to conventional CVI work. A reduction in cost of a factor of 20 has been calculated. A larger, commercial microwave system has been designed for scaled up prototype part fabrication.

Chemical vapor infiltration

Ceramic matrix composite

Deposition

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Grain Structure and Growth of Dispersed Phase BN-AlN Coatings Grown via Chemical Vapor Deposition

MRS Proceedings (1990)

G. B. Freeman Woo Y. Lee W. J. Lackey John A. Hanigofsky Karren L. More

10.1557/proc-202-155

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Continuous Fabrication of Silicon Carbide Fiber Tows by Chemical Vapor Deposition

Journal of the American Ceramic Society (1995)

W. J. Lackey John A. Hanigofsky G. B. Freeman Regina D. Hardin Ajit Prasad

The feasibility of preparing small‐diameter, high‐strength, thermally stable silicon carbide fiber tows by the continuous chemical vapor deposition (CVD) of SiC onto carbon fiber tows was experimentally evaluated. Calculations of bending stresses and stresses caused by thermal expansion mismatch between the substrate and coating were used to evaluate the influence of coating thickness and substrate fiber diameter and type. Statistically designed and analyzed processing studies quantitatively showed the influence of key CVD process variables (temperature, pressure, and flow rates of CH 3 SiCl 3 and H 2 ) on fiber attributes such as coating thickness and uniformity, surface roughness, percent agglomeration, and strength. Emphasis was given to conceiving and evaluating various fiber spreading devices in order to enhance coating uniformity and to minimize filament agglomeration within a tow. Uniform coatings and fiber tensile strengths as high as 4 GPa were achieved.

Deposition

10.1111/j.1151-2916.1995.tb08852.x

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Citations (30)

Thermodynamic analysis for the chemical vapor deposition of composite coatings from the Al–B–Ti–N–H–Cl–Ar system

Journal of materials research/Pratt's guide to venture capital sources (1992)

T. S. Moss John A. Hanigofsky W. J. Lackey

Deposition

Molar ratio

10.1557/jmr.1992.0754

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Citations (3)

Continuous Fiber Coating System

Ceramic engineering and science proceedings (2008)

W. J. Lackey John A. Hanigofsky Michael T. Groves Jospeh A. Heaney

A chemical vapor deposition (CVD) system for continuously coating fiber tows and monofilaments was designed, fabricated, and successfully operated. The fiber travels vertically up through the center of the gas injector and then through a hot wall CVD furnace. Fiber handling equipment is contained in gas-tight enclosures located above and below the reactor. The system is capable of operation at reduced pressure and has been used successfully for the deposition of YBa2Cu3Ox, BN, SiC, and other coatings.

Deposition

10.1002/9780470313831.ch11

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Citations (23)

Ceramic Composite Combustor Cans for Expendable Turbine Engines.

Larry Fehrenbacher John A. Hanigofsky

Abstract : Ceramic matrix composite fabrication by microwave assisted chemical vapor infiltration (MWCVI) has been demonstrated as a feasible, faster, and more economical technique as compared to conventional CVI. Two deposition systems, carbon and silicon carbide, were investigated using this processing technique. Densification rates over an order of magnitude higher have been achieved on small cylindrical Nicalon fiber preforms. Economic forecasts based on previous SiC depositionandthis Phase I work shows a significant improvement in part cost as compared to conventional CVI work. A reduction in cost of a factor of 20 has been calculated. A larger, commercial microwave system has been designed for scaled up prototype part fabrication.

Chemical vapor infiltration

Ceramic matrix composite

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Experimental Whisker Growth and Thermodynamic Study of the Hafnium-Carbon System for Chemical Vapor Deposition Applications

Journal of the American Ceramic Society (1990)

W. J. Lackey John A. Hanigofsky G. B. Freeman

Chemical vapor deposition of nonstoichiometric hafnium carbide is studied by computer minimization of the Gibbs free energy of the system. Isostoichiometric curves in the HfC 1‐ x region of the deposition diagram are calculated as a function of HfCI 4 , CH 4 , and H 2 concentration and reaction temperature. Possible experimental reactions are investigated using thermodynamic efficiency and partial pressure diagrams. A comparison between the calculated solid‐phase regions and the HfC phase diagram is given, and experimental results for HfC whiskers are also compared with the calculations.

Hafnium

Deposition

Partial pressure

10.1111/j.1151-2916.1990.tb09801.x

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Citations (16)

Rapid Chemical Vapor Deposition of Yba₂cu₃o_x Coatings

MRS Proceedings (1989)

W. J. Lackey W.B. Carter D. N. Hill E. Kent Barefield John A. Hanigofsky

Sublimation

Deposition

10.1557/proc-169-585

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Citations (2)