Accession Number : AD0658041

Title :   A STUDY OF THE ZIRCONIA-HAFNIA SYSTEM.

Descriptive Note : Summary rept. 1 May 63-30 Apr 64,

Corporate Author : IIT RESEARCH INST CHICAGO ILL

Personal Author(s) : Domagala,R. F.

Report Date : APR 1964

Pagination or Media Count : 28

Abstract : A definitive study of phase relationships in the ZrO2-HfO2 system was conducted. Metallographic, X-ray, differential-thermal, and microprobe analyses were applied to annealed and quenched specimens of arc-melted compositions. The system forms a continuous series of solid solutions in the low-temperature monoclinic structure as well as the high-temperature tetragonal structure. There is a relatively small intervening monoclinic plus tetragonal two-phase solid solution field. This field lies approximately on a straight line connecting the inversion temperatures of the two oxides. The melting points of ZrO2-HfO2 compositions likewise lie roughly on a line connecting the melting point of each oxide. There are no intervening complex oxides. Effort was also directed toward a better definition of the high-temperature, high-hafnium region of the Hf-O system. This study was brought to a conclusion and a final Hf-O diagram is presented. (Author)

Descriptors :   (*CERAMIC MATERIALS, PHASE DIAGRAMS), (*ZIRCONIUM OXIDES, PHASE STUDIES), (*HAFNIUM COMPOUNDS, PHASE STUDIES), OXIDES, SOLID SOLUTIONS, METALLOGRAPHY, X RAY DIFFRACTION, DIFFERENTIAL THERMAL ANALYSIS, PROBES, THERMOCOUPLES, CRYSTAL STRUCTURE, MELTING POINT

Subject Categories : Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE