Improved silicon nitride for advanced heat engines. Final report

Technical Report · Mon Apr 01 04:00:00 EST 1991

OSTI ID:6254972

Yeh, H C; Fang, H T

The results of a four year program to improve the strength and reliability of injection-molded silicon nitride are summarized. Statistically designed processing experiments were performed to identify and optimize critical processing parameters and compositions. Process improvements were monitored by strength testing at room and elevated temperatures, and microstructural characterization by optical, scanning electron microscopes, and scanning transmission electron microscope. Processing modifications resulted in a 20 percent strength and 72 percent Weibull slope improvement of the baseline material. Additional sintering aids screening and optimization experiments succeeded in developing a new composition (GN-10) capable of 581.2 MPa at 1399 C. A SiC whisker toughened composite using this material as a matrix achieved a room temperature toughness of 6.9 MPa m(exp .5) by the Chevron notched bar technique. Exploratory experiments were conducted on injection molding of turbocharger rotors.

• Research Organization: Allied-Signal Aerospace Co., Torrance, CA (United States)
• OSTI ID: 6254972
• Report Number(s): N-93-29451; NASA-CR--182193; REPT--88-61608; NAS--1.26:182193; CNN: NAS3-24385; RTOP 533-05-01
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360203 -- Ceramics
Cermets
& Refractories-- Mechanical Properties
360601 -- Other Materials-- Preparation & Manufacture
360603 -- Materials-- Properties
CARBIDES
CARBON COMPOUNDS
CRYSTALS
FABRICATION
FRACTURE PROPERTIES
INJECTION
INTAKE
MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
MOLDING
MONOCRYSTALS
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
PROCESSING
REINFORCED MATERIALS
SILICON CARBIDES
SILICON COMPOUNDS
SILICON NITRIDES
SINTERING
WHISKERS