Pyrolytic boron nitride coatings on ceramic yarns and fabrication of insulations. Final Report, Dec. 1989 - Nov. 1991

Technical Report · Wed Jan 01 04:00:00 EST 1992

OSTI ID:5702098

Moore, A W

Pyrolytic boron nitride (PBN) was deposited on Nicalon NL 202 silicon carbide yarns at 1000 to 1200 C with the goal of improving the resistance of the Nicalon to deterioration in an aerodynamic environment at temperatures up to 1000 C. For continuous coating, the yarns were fed through the deposition chamber of a pilot plant sized CVD furnace at a rate of about 2 feet per minute. PBN coatings were obtained by reacting boron trichloride and ammonia gases inside the deposition chamber. Most of the PBN coatings were made at around 1080 C to minimize thermal degradation of the Nicalon. Pressures were typically below 0.1 Torr. The coated yarns were characterized by weight per unit length, tensile strength and modulus, scanning electron microscopy, and scanning Auger microscopy. The PBN coated Nicalon was woven into cloth, but was not entirely satisfactory as a high temperature sizing. Several 13 in. square pieces of Nicalon cloth were coated with PBN in a batch process in a factory sized deposition furnace. Samples of cloth made from the PBN coated Nicalon were sewn into thermal insulation panels, whose performance is being compared with that of panels made using uncoated Nicalon.

• Research Organization: Union Carbide Corp., Parma, OH (United States)
• OSTI ID: 5702098
• Report Number(s): N-92-16145; NASA-CR--189817; NAS--1.26:189817; CNN: NAS2-13109
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
AMMONIA
BORON COMPOUNDS
BORON NITRIDES
CARBIDES
CARBON COMPOUNDS
CERAMICS
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
COATINGS
DEPOSITION
ELECTRON MICROSCOPY
FABRICATION
HYDRIDES
HYDROGEN COMPOUNDS
MECHANICAL PROPERTIES
MICROSCOPY
NITRIDES
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
PNICTIDES
SILICON CARBIDES
SILICON COMPOUNDS
SURFACE COATING
TENSILE PROPERTIES
THERMAL DEGRADATION
THERMAL INSULATION
VAPOR DEPOSITED COATINGS