Investigation of the lanthanide sesquioxides as high temperature transformation toughening agents

Book · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5929270

Jero, P D

One of the recent bright spots in the field of engineered materials was the developed of transformation toughened ZrO/sub 2/ ceramics. This one discovery led to a whole new class of strong, tough engineered ceramics. Recently, Kriven reviewed phase transformations in a number of inorganic materials which show potential as transformation toughening agents. Amongst those materials are the lanthanide sesquioxides. Known for their thermal stability, several of the lanthanide sesquioxides exhibit, on cooling, the requisite rapid phase transformation from a high temperature monoclinic (B) phase to a less dense low temperature cubic (C) phase. The volume expansion is about 8 to 10%, but the transformation mechanism is not known. The transformation is in several ways similar to the martensitic tetragonal to monoclinic transformation in ZrO/sub 2/. The aim of this work was to investigate the C/Longleftrightarrow/B transformation in the lanthanide sesquioxides and evaluate their potential as transformation toughening agents, particularly at high temperature. A detailed description of the lanthanide sesquioxides serves (1) to introduce the reader to a subject which may well be new to him or her and (2) to indicate the complexity of the materials being examined. The literature is voluminous and yet relatively few researchers have studied these materials. Two groups, one in France, the other in the USSR, account for much of the basic research done so far. This results, undoubtedly, from the fact that ultra high temperatures are often required in the study of these materials. Both of the above groups have ultra high temperature solar furnaces with x-ray diffraction and thermal analysis attachments. 218 references.

• OSTI ID: 5929270
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ACTIVATION ENERGY
ADSORPTION
ALKALINE EARTH METAL COMPOUNDS
ALLOY SYSTEMS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BENDING
BINARY ALLOY SYSTEMS
BRITTLENESS
CALCIUM COMPOUNDS
CALCIUM OXIDES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CERAMICS
CHALCOGENIDES
CHEMICAL ANALYSIS
COHERENT SCATTERING
COLOR
COMPRESSION STRENGTH
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DENSITY
DIAGRAMS
DIFFERENTIAL THERMAL ANALYSIS
DIFFRACTION
DYSPROSIUM COMPOUNDS
DYSPROSIUM OXIDES
ELECTRON MICROSCOPY
ENERGY
EUROPIUM COMPOUNDS
EUROPIUM OXIDES
EXPANSION
FRACTURE PROPERTIES
GADOLINIUM COMPOUNDS
GADOLINIUM OXIDES
GRAVIMETRIC ANALYSIS
HARDNESS
HEAT TREATMENTS
HOLMIUM COMPOUNDS
HOLMIUM OXIDES
HYDROGEN COMPOUNDS
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MECHANICAL PROPERTIES
METALLURGY
MICROSCOPY
OPTICAL PROPERTIES
ORGANOLEPTIC PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PARTICLE SIZE
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POWDER METALLURGY
PRESSURE EFFECTS
QUANTITATIVE CHEMICAL ANALYSIS
RARE EARTH COMPOUNDS
SAMARIUM COMPOUNDS
SAMARIUM OXIDES
SCANNING ELECTRON MICROSCOPY
SCATTERING
SIZE
SORPTION
STOICHIOMETRY
TEMPERATURE EFFECTS
TERBIUM COMPOUNDS
TERBIUM OXIDES
THERMAL ANALYSIS
THERMAL EXPANSION
THERMAL GRAVIMETRIC ANALYSIS
TRANSITION ELEMENT COMPOUNDS
TRANSMISSION ELECTRON MICROSCOPY
TWINNING
WATER
X-RAY DIFFRACTION
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES