Formation, characterization, and hot isostatic pressing of Cr{sub 2}O{sub 3}-doped ZrO{sub 2} (0,3 mol% Y{sub 2}O{sub 3}) prepared by hydrazine method

Journal Article · Mon Jan 01 00:00:00 EST 1996 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1996.tb07895.x· OSTI ID:203548

Hirano, Shingo; Yoshinaka, Masaru; Hirota, Ken; Yamaguchi, Osamu ^[1]

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1. Doshisha Univ., Kyoto Tanabe (Japan)

In the ZrO{sub 2}-Cr{sub 2}O{sub 3} system, metastable t-ZrO{sub 2} solid solutions containing up to 11 mol% Cr{sub 2}O{sub 3} crystallize at low temperatures from amorphous materials prepared by the hydrazine method. The lattice parameter c decreases linearly from 0.5149 to 0.5077 nm with increased Cr{sub 2}O{sub 3} content, whereas the lattice parameter a is a constant value (a = 0.5077 nm) regardless of the starting composition. At higher temperatures, transformation (decomposition) of the solid solutions proceeds in the following way: t(ss) {yields} t(ss) + m + Cr{sub 2}O{sub 3} {yields} m + Cr{sub 2}O{sub 3}. Above 11 mol% Cr{sub 2}O{sub 3} addition, c-ZrO{sub 2} phases are formed in the presence of Cr{sub 2}O{sub 3}. The t-ZrO{sub 2} solid solution powders have been characterized for particle size, shape, and surface area. They consist of very fine particles (15--30 nm) showing thin platelike morphology. Dense ZrO{sub 2}(3Y)-Cr{sub 2}O{sub 3} composite ceramics ({approx} 99.7% of theoretical) with an average grain size of 0.3 {micro}m have been fabricated by hot isostatic pressing for 2 h at 1,400 C and 196 MPa. Their fracture toughness increases with increased Cr{sub 2}O{sub 3} content. The highest K{sub 1c} value of 9.5 MPa {center_dot} m{sup 1/2} is achieved in the composite ceramics containing 10 mol% Cr{sub 2}O{sub 3}.

• Sponsoring Organization: USDOE
• OSTI ID: 203548
• Journal Information: Journal of the American Ceramic Society, Vol. 79, Issue 1; Other Information: PBD: Jan 1996
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
30 DIRECT ENERGY CONVERSION
08 HYDROGEN FUEL
ZIRCONIUM OXIDES
SYNTHESIS
CRYSTAL STRUCTURE
HOT PRESSING
FRACTURE PROPERTIES
YTTRIUM OXIDES
CHROMIUM OXIDES
MHD GENERATORS
MATERIALS
HYDROGEN GENERATORS
CHLORIDES
AQUEOUS SOLUTIONS
DOPED MATERIALS
LATTICE PARAMETERS
SOLID SOLUTIONS
PARTICLE SIZE
SHAPE
SURFACE AREA
SINTERING