Thermochemical properties of group IVB and VB transition metal alloys with platinum group metals: acid-base stabilization

Technical Report · Tue Jul 01 00:00:00 EDT 1986

OSTI ID:5034940

Cima, M J

Solid-state galvanic cell measurements and oxide equilibration experiments are used to derive thermochemical quantities for a variety of acid-base stabilized alloys such as Nb-Pd, Nb-Rh, Ti-Pd, and Ti-Rh. The experiments have effectively resulted in the titration of palladium by niobium metal. The excess partial molar Gibbs energy of niobium at infinite dilution was determined to be -62 kcal/mole at 1000/sup 0/C and the Gibbs energy of formation of NbPd/sub 3.55/ is -42 kcal/mole. These results and those for the other systems are used to assess the importance of crystal field effects in the context of the generalized Lewis acid-base theory. The ternary phase diagrams for the Pd-Nb-O and Rh-Nb-O systems were obtained from the characterization of samples equilibrated at 1000/sup 0/C. Powder x-ray diffraction patterns were measured for several equilibrium oxides that are substoichiometric of Nb/sub 2/O/sub 5/ and are found to be consistent with crystal structures previously determined from single crystals of similar composition. An improved method was developed for composition measurements of binary metallic alloy grains using energy dispersive x-ray analysis and a scanning electron microscope. The effects of different processing methods were also explored in the preparation of optically transparent yttria doped thoria (YDT) pellets, and techniques for the preparation of reliable YDT solid electrolytes are presented.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5034940
• Report Number(s): LBL-21951; ON: DE87001879
• Resource Relation: Other Information: Thesis. Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
25 ENERGY STORAGE
NIOBIUM OXIDES
PHASE DIAGRAMS
PALLADIUM OXIDES
PLATINUM METAL ALLOYS
THERMODYNAMIC PROPERTIES
RHODIUM OXIDES
SOLID ELECTROLYTES
PRODUCTION
THORIUM OXIDES
TRANSITION ELEMENT ALLOYS
CRYSTAL FIELD
DOPED MATERIALS
X-RAY DIFFRACTION
YTTRIUM OXIDES
ACTINIDE COMPOUNDS
ALLOYS
CHALCOGENIDES
COHERENT SCATTERING
DIAGRAMS
DIFFRACTION
ELECTROLYTES
MATERIALS
NIOBIUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PALLADIUM COMPOUNDS
PHYSICAL PROPERTIES
REFRACTORY METAL COMPOUNDS
RHODIUM COMPOUNDS
SCATTERING
THORIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
360104* - Metals & Alloys- Physical Properties
360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies
250903 - Energy Storage- Batteries- Materials
Components
& Auxiliaries