Crystallization of MgO-Al/sub 2/O/sub 3/-SiO/sub 2/-ZrO/sub 2/ glasses
The crystallization of MgO-Al/sub 2/O/sub 3/-SiO/sub 2/-ZrO/sub 2/ glasses at 1000/sup 0/C was studied. Isothermal heat treatments of a cordierite-based glass (2MgO.2Al/sub 2/O/sub 3/.5SiO/sub 2/ equal to Mg/sub 2/Al/sub 4/Si/sub 5/O/sub 18/) with 7 wt% ZrO/sub 2/ produced surface crystallization of ..cap alpha..-cordierite and tetragonal ZrO/sub 2/ (t-ZrO/sub 2/). These phases advanced into the glass by cocrystallization of t-ZrO/sub 2/ rods in an ..cap alpha..-cordierite matrix with a well-defined orientation relation. The t-ZrO/sub 2/ were unstable with respect to diffusional breakup (a Raleigh instability) and decomposed into rows of aligned ellipsoidal and spheroidal particles. The t-ZrO/sub 2/ was very resistant to transformation to monoclinic symmetry. With a similar glass containing 15 wt% ZrO/sub 2/, surface crystallization of ..cap alpha..-cordierite and t-ZrO/sub 2/ was accompanied by internal crystallization of t-ZrO/sub 2/ dendrites. Transformation of the dendrites to monoclinic symmetry was observed under some conditions.
- Research Organization:
- Dept. of Metallurgy and Materials Science, Case Western Reserve Univ., Cleveland, OH 44106
- OSTI ID:
- 5743546
- Journal Information:
- J. Am. Ceram. Soc.; (United States), Vol. 69:3
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mechanical properties of cordierite-based composites obtained by sol-gel techniques
Sintering and grain growth of silicon nitride ceramics in presence of reactive liquid
Related Subjects
ALUMINIUM OXIDES
CRYSTALLIZATION
MAGNESIUM OXIDES
SILICON OXIDES
ZIRCONIUM OXIDES
DENDRITES
GLASS
GRAIN ORIENTATION
PARTICLES
SYMMETRY
VERY HIGH TEMPERATURE
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CRYSTAL STRUCTURE
CRYSTALS
MAGNESIUM COMPOUNDS
MICROSTRUCTURE
ORIENTATION
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360602 - Other Materials- Structure & Phase Studies