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