Vapor transport of zirconium and silicon during heat-treatment of Zircaloy in silica

Journal Article · Mon Dec 31 23:00:00 EST 1979 · J. Electrochem. Soc.; (United States)

DOI:https://doi.org/10.1149/1.2129642· OSTI ID:5509870

Knittel, D R; Cubicciotti, D

When pieces of Zircaloy are heated above 600/sup 0/C in sealed silica capsules, silicon is deposited on the Zircaloy surface as zirconium silicides and zirconium is deposited on the silica in two forms: as an oxide layer in the high temperature region and as a metallic mirror on lower temperature surfaces. Samples of Zircaloy were heated in silica capsules under various conditions and analyzed by scanning electron microscopy. The results indicate that the deposits resulted from vapor transport processes involving volatile zirconium and silicon fluorides. Residual fluoride on Zircaloy surfaces, remaining from acid pickling treatments, was observed by Auger electron spectroscopy and mass spectroscopy in amounts sufficient to cause the transport. The thermodynamics of the vapor transport reactions are in accord with the fluoride mechanism. 4 figures.

• Research Organization: SRI International, Menlo Park, CA
• OSTI ID: 5509870
• Journal Information: J. Electrochem. Soc.; (United States), Journal Name: J. Electrochem. Soc.; (United States) Vol. 127:1; ISSN JESOA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
DEPOSITION
ELECTRON MICROSCOPY
ELEMENTS
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
GASES
HALIDES
HALOGEN COMPOUNDS
HEAT TREATMENTS
HIGH TEMPERATURE
METALS
MICROSCOPY
SCANNING ELECTRON MICROSCOPY
SEMIMETALS
SILICIDES
SILICON
SILICON COMPOUNDS
SILICON FLUORIDES
TEMPERATURE EFFECTS
THERMODYNAMICS
TIN ALLOYS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VAPORS
ZIRCALOY
ZIRCONIUM
ZIRCONIUM ALLOYS
ZIRCONIUM BASE ALLOYS
ZIRCONIUM COMPOUNDS
ZIRCONIUM FLUORIDES
ZIRCONIUM SILICIDES