Crystallization behavior and properties of BaO-Al sub 2 O sub 3 -2SiO sub 2 glass matrices

Conference · Thu Feb 01 04:00:00 EST 1990

OSTI ID:6818799

Drummond, III, C H; Bansal, N P

Glass of stoichiometric celsian composition, BaO-Al{sub 2}O{sub 3}-2SiO{sub 2}, is a potential glass-ceramic matrix for high-temperature composites. The glass has a density of 3.39 g/cu cm, thermal expansion coefficient of 6.6 x 10(exp -6)/deg C glass transition temperature of 910 C, and dilatometric softening point of 925 C. On heat treatment, only hexacelsian crystallized out on the surface, but both celsian and hexacelsian were present in the bulk. Effects of cold isostatic pressing (CIP), sintering, and hot pressing, in the presence and absence of an additive, on the formation of the celsian phase in the glass were studied. CIP'ed samples, after appropriate heat treatments, always crystallized out as celsian whereas the presence of 5 to 10 weight percent of an additive was necessary for formation of celsian in sintered as well as hot pressed specimens. Green density increased with CIP'ing pressure but had no effect on sintered density. Hot pressing resulted in fully dense samples.

• Research Organization: Ohio State Univ., Columbus, OH (USA)
• OSTI ID: 6818799
• Report Number(s): N-90-19374; NASA-CR--185209; E--5314; NAS--1.26:185209; CONF-900160--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
ADDITIVES
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COLD PRESSING
CRYSTALLIZATION
EXPANSION
FABRICATION
GLASS
HEAT TREATMENTS
HIGH TEMPERATURE
HOT PRESSING
MATERIALS
MATERIALS WORKING
MATRIX MATERIALS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PRESSING
SILICON COMPOUNDS
SILICON OXIDES
SINTERING
STOICHIOMETRY
THERMAL EXPANSION
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE