Mechanism and kinetics of sintering of nonstoichiometric Y-Ba-Cu-O powders
- Kharkov State Univ. (Russian Federation); and others
Using high-resolution optical and scanning electron microscopy with x-ray microanalysis at temperatures of 880 to 920{degrees}C, we studied the kinetics and mechanism of the formation of intergranular contacts during sintering of powder-substrate models and also studied the mechanism of shrinkage during sintering of Y-Ba-Cu-O compacts with a stoichiometric composition and two nonstoichiometric compositions, YO{sub O.95}Ba{sub 2}CU{sub 3}O{sub Y} and Y{sub 1.05}Ba{sub 2}CU{sub 3}O{sub Y}. The formation and the shrinkage of powders of different compositions were found to be described by equations of different degrees, which points to different diffusion sintering mechanisms. Powders with stoichiometric and hyperstoichiometric compositions are sintered by a volume diffusion mechanism, which is controlled by the slowest ion, Y{sup 3+}. Powders with a substoichiometric composition (Y-0.95) are sintered like a liquid phase, i.e., is controlled by diffusion through liquid or solid layers where new phases with higher diffusion coefficients are formed as a result of segregation effects.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 237596
- Journal Information:
- Powder Metallurgy and Metal Ceramics, Vol. 33, Issue 9-10; Other Information: PBD: Mar 1995; TN: Translated from Poroshkovaya Metallurgiya; Nos. 9-10, 11-16(Sep-Oct 1994)
- Country of Publication:
- United States
- Language:
- English
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