The system HfO{sub 2}-Y{sub 2}O{sub 3}-Er{sub 2}O{sub 3}

Journal Article · Fri Mar 01 04:00:00 EST 1996 · Journal of the American Ceramic Society

OSTI ID:230745

Andrievskaya, E R; Lopato, L M; Smirnov, V P ^[1]

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1. Inst. of Materials Science Problems, Kiev (Ukraine)

A mathematical model of the liquidus surface based on a reduced polynomial method was proposed for the system HfO{sub 2}-Y{sub 2}O{sub 3}-Er{sub 2}O{sub 3}. The results of calculations according to this model agree fairly well with the experimental data. Phase equilibria in the system HfO{sub 2}-Y{sub 2}O{sub 3}-Er{sub 2}O{sub 3} were studied on melted (as-cast) and annealed samples using X-ray diffraction (at room and high temperatures) and microstructural and petrographic analyses. The crystallization paths in the system HfO{sub 2}-Y{sub 2}O{sub 3}-Er{sub 2}O{sub 3} were established. The system HfO{sub 2}-Y{sub 2}O{sub 3}-Er{sub 2}O{sub 3} is characterized by the formation of extended solid solutions based on the fluorite-type (F) form of HfO{sub 2} and cubic (C) and hexagonal (H) forms of Y{sub 2}O{sub 3} and Er{sub 2}O{sub 3}. The boundary curves of these solid solutions have the minima at 2,370 C (15.5 mol% HfO{sub 2}, 49.5 mol% Y{sub 2}O{sub 3}) and 2,360 C (10.5 mol% HfO{sub 2}, 45.5 mol% Y{sub 2}O{sub 3}). No compounds were found to exist in the system investigated.

• OSTI ID: 230745
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 3 Vol. 79; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
CHEMICAL COMPOSITION
CRYSTAL-PHASE TRANSFORMATIONS
CRYSTALLIZATION
ERBIUM OXIDES
HAFNIUM OXIDES
LIQUIDS
MATHEMATICAL MODELS
PHASE STUDIES
SOLID SOLUTIONS
SOLIDIFICATION
X-RAY DIFFRACTION
YTTRIUM OXIDES