Heat treatment and additive effects on microstructure and properties of tetragonal-(2-3 mol%) yttria-stabilized zirconia

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:5945982

Baskaran, S

The role of selected additives (Al{sub 2}O{sub 3}, yttrium aluminum garnet and Zr) in microstructural development, phase stability and mechanical behavior of predominantly-tetragonal (2-3 mol%) yttria-stabilized-zirconia (YSZ) was investigated. Preliminary studies on compositional effects were studied in 2-3 mol% YSZ prepared from a mixed oxide powder. Microstructure-property relationships were then investigated as a function of heat treatment conditions in 3 mol% YSZ prepared from a commercially available co-precipitated powder. Additive effects on microstructure and mechanical properties were studied for optimized heat treatment schedules in the 3mol% YSZ system. For the YSZ-Al{sub 2}O{sub 3} system, microstructures developed from mechanical mixing of YSZ powder were compared with microstructures obtained from nitrate-synthesized powders. The strength-toughness relationships observed in the 3 mol% YSZ system were correlated with the grain size dependence of the mechanical properties. Grain sizes were optimized for either high toughness or high strengths ({approx}820 MPa). The role of Al{sub 2}O{sub 3} in microstructural control was found to depend strongly on the mode of dispersion during processing. Additions of up to 6.5 wt% Al{sub 2}O{sub 3} resulted in less than {plus minus} 15% variation in strength and toughness for all heat treatments studied. The intergranular dispersion of Al{sub 2}O{sub 3} was accompanied by a decrease in conductivity in 3 mol% YSZ prepared from the commercially available powder. Addition of yttrium aluminum garnet (YAG) resulted in the formation of cubic-related phases, improved low-temperature phase stability and low strengths.

• Research Organization: Illinois Univ., Urbana, IL (USA)
• OSTI ID: 5945982
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
METALLURGICAL EFFECTS
YTTRIUM OXIDES
MECHANICAL PROPERTIES
MICROSTRUCTURE
ZIRCONIUM
ZIRCONIUM OXIDES
ADDITIVES
GRAIN SIZE
HEAT TREATMENTS
OPTIMIZATION
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CRYSTAL STRUCTURE
ELEMENTS
METALS
OXIDES
OXYGEN COMPOUNDS
SIZE
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YTTRIUM COMPOUNDS
ZIRCONIUM COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360203 - Ceramics
Cermets
& Refractories- Mechanical Properties