Synthesis of Ba sub 2 YCu sub 3 O sub 7 by the SCD method using amino acid salt reducing agents

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Journal of Solid State Chemistry; (USA)

DOI:https://doi.org/10.1016/0022-4596(90)90187-3· OSTI ID:6624085

Kourtakis, K; Robbins, M; Gallagher, P K ^[1]

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1. AT T Bell Labs., Murray Hill, NJ (USA)

The anionic oxidation-reduction or SCD method relies on an internal oxidation-reduction reaction which converts spray-dried precursors into intimately mixed and highly reactive metal oxide powders. Earlier studies focused on precursor mixtures containing oxidizing components such as NO{sub 3}{sup {minus}} salts with reducing salts (RCOO{sup {minus}}, where R is H, CH{sub 3} or CH{sub 2}CH{sub 3}) which react to form Ba{sub 2}YCu{sub 3}O{sub 7} powder. In this work, amino acid reducing agents are used. The impact of the functional group change, in the reducing agent of the NO{sub 3}{sup {minus}}/amino acid precursors, is shown by DSC to result in sharp (and therefore rapid) oxidation-reduction reactions which occur at lower temperatures. The trend in reaction temperature correlates inversely with the expected basicity of the amino group in the series (numbers in parentheses represent mole ratios): CH{sub 3}CH(NH{sub 3})COO{sup {minus}}/NO{sub 3}{sup {minus}} (4/9) = 206{degree}C > NH{sub 2}CH{sub 2}COO{sup {minus}}/NO{sub 3}{sup {minus}} (4/9) = 195{degree}C > NH{sub 2}CH{sub 2}CH{sub 2}COO{sup {minus}}/NO{sub 3}{sup {minus}} (4/9) = 191{degree}C. The mixed oxide product is highly reactive and can be converted to single-phase Ba{sub 2}YCu{sub 3}O{sub x} when fired at 900-910{degree}C for 10 min in flowing oxygen.

• OSTI ID: 6624085
• Journal Information: Journal of Solid State Chemistry; (USA), Journal Name: Journal of Solid State Chemistry; (USA) Vol. 84:1; ISSN 0022-4596; ISSN JSSCB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400200 -- Inorganic
Organic
& Physical Chemistry
ALKALINE EARTH METALS
BARIUM
CHALCOGENIDES
CHEMICAL REACTIONS
COMPOSITE MATERIALS
COPPER COMPOUNDS
COPPER OXIDES
DATA
DATA ANALYSIS
ELEMENTS
EXPERIMENTAL DATA
INFORMATION
MATERIALS
MEASURING INSTRUMENTS
MEASURING METHODS
METALS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
REDOX REACTIONS
SUPERCONDUCTING COMPOSITES
SYNTHESIS
THERMAL ANALYSIS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YTTRIUM