Solution based preparation of Perovskite-type oxide films and powders

Thesis/Dissertation · Sat Apr 01 00:00:00 EST 1995

DOI:https://doi.org/10.2172/42452· OSTI ID:42452

McHale, Jr., James M. ^[1]

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1. Temple Univ., Philadelphia, PA (United States). Dept. of Chemistry

Conventional solid state reactions are diffusion limited processes that require high temperatures and long reaction times to reach completion. In this work, several solution based methods were utilized to circumvent this diffusion limited reaction and achieve product formation at lower temperatures. The solution methods studied all have the common goal of trapping the homogeneity inherent in a solution and transferring this homogeneity to the solid state, thereby creating a solid atomic mixture of reactants. These atomic mixtures can yield solid state products through "diffusionless" mechanisms. The effectiveness of atomic mixtures in solid state synthesis was tested on three classes of materials, varying in complexity. A procedure was invented for obtaining the highly water soluble salt, titanyl nitrate, TiO(NO₃)₂, in crystalline form, which allowed the production of titanate materials by freeze drying. The freeze drying procedures yielded phase pure, nanocrystalline BaTiO₃ and the complete SYNROC-B phase assemblage after ten minute heat treatments at 600{degrees}C and 1100{degrees}C, respectively. Two novel methods were developed for the solution based synthesis of Ba₂YCu₃O_7-x and Bi₂Sr₂Ca₂Cu₃O₁₀. Thin and thick films of Ba₂YCu₃O_7-x and Bi₂Sr₂Ca₂u₃O₁₀ were synthesized by an atmospheric pressure, chemical vapor deposition technique. Liquid ammonia solutions of metal nitrates were atomized with a stream of N₂O and ignited with a hydrogen/oxygen torch. The resulting flame was used to coat a substrate with superconducting material. Bulk powders of Ba₂YCu₃O_7-x and Bi₂Sr₂Ca₂Cu₃O₁₀ were synthesized through a novel acetate glass method. The materials prepared were characterized by XRD, TEM, SEM, TGA, DTA, magnetic susceptibility and electrical resistivity measurements.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 42452
• Report Number(s): LA-12825-T; ON: DE95009089; TRN: 95:003504
• Resource Relation: Other Information: TH: Thesis (Ph.D.); PBD: Apr 1995
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
TITANATES
CHEMICAL PREPARATION
BARIUM COMPOUNDS
CUPRATES
CALCIUM COMPOUNDS
BISMUTH COMPOUNDS
STRONTIUM COMPOUNDS
YTTRIUM COMPOUNDS
FILMS
POWDERS
X-RAY DIFFRACTION
TRANSMISSION ELECTRON MICROSCOPY
SCANNING ELECTRON MICROSCOPY
THERMAL GRAVIMETRIC ANALYSIS
DIFFERENTIAL THERMAL ANALYSIS
MAGNETIC SUSCEPTIBILITY
ELECTRIC CONDUCTIVITY