Gelcasting of sub-micron alumina, sialon, and silicon nitride powders

Conference · Mon Jan 01 00:00:00 EST 1990

OSTI ID:6550865

Omatete, O O; Strehlow, R A; Walls, C A

Gelcasting is a near-net-shape forming technique that is applicable to various types of powders. It is accomplished by casting a concentrated suspension of a commercial ceramic powder in a solution of a polymerizable monomer and then polymerizing. A filled gel is formed, which is dried and processed further. Alumina, sialon, and silicon nitride parts of various geometries have been made and are described. Emphasis is placed on the unit-operations of the process. Because a requirement of the process is a castable suspension of more than 50 vol % solids loading, good dispersion is crucial. Drying, another key process, has been studied extensively. Shrinkage from the cast size occurs during drying and further shrinkage occurs during sintering. Data on the relationship of physical properties of products to some of the more significant processing variables is discussed. Emphasis is also placed on the machinability of the dried gelled body. Because the body at this stage is quite durable, green part machining is feasible. The monomer used in the process is acrylamide, which undergoes a vinyl polymerization. Environmental, safety and hygiene issues are summarized. 9 refs., 6 figs.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: DOE/CE
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6550865
• Report Number(s): CONF-9010201-1; ON: DE91000618
• Resource Relation: Conference: 37. Sagamore army materials research conference, Plymouth, MA (USA), 1-4 Oct 1990
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CASTING
SILICON NITRIDES
DRYING
GELS
POLYMERIZATION
POWDERS
SHRINKAGE
TENSILE PROPERTIES
TESTING
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
COLLOIDS
DISPERSIONS
FABRICATION
MECHANICAL PROPERTIES
NITRIDES
NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PNICTIDES
SILICON COMPOUNDS
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication