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Title: Electrically insulating films deposited on V-4%Cr-4%Ti by reactive CVD

Abstract

In the design of liquid-metal blankets for magnetic fusion reactors, corrosion resistance of structural materials and the magnetohydrodynamic forces and their influence on thermal hydraulics and corrosion are major concerns. Electrically insulating CaO films deposited on V-4%Cr-4%Ti exhibit high-ohmic insulator behavior even though a small amount of vanadium from the alloy become incorporated into the film. However, when vanadium concentration in the film is > 15 wt.%, the film becomes conductive. When the vanadium concentration is high in localized areas, a calcium vanadate phase that exhibits semiconductor behavior can form. The objective of this study is to evaluate electrically insulating films that were deposited on V-4%Cr-4%Ti by a reactive chemical vapor deposition (CVD) method. To this end, CaO and Ca-V-O coatings were produced on vanadium alloys by CVD and by a metallic-vapor process to investigate the electrical resistance of the coatings. The authors found that the Ca-V-O films exhibited insulator behavior when the ratio of calcium concentration to vanadium concentration R in the film > 0.9, and semiconductor or conductor behavior when R < 0.8. However, in some cases, semiconductor behavior was observed when CaO-coated samples with R > 0.98 were exposed in liquid lithium. Based on these studies, theymore » conclude that semiconductor behavior occurs if a conductive calcium vanadate phase is present in localized regions in the CaO coating.« less

Authors:
Publication Date:
Research Org.:
Argonne National Lab., Energy Technology Div., IL (United States)
Sponsoring Org.:
USDOE Office of Energy Research, Washington, DC (United States)
OSTI Identifier:
663566
Report Number(s):
ANL/ET/CP-95685; CONF-981023-
ON: DE98057804; TRN: 99:000237
DOE Contract Number:  
W-31109-ENG-38
Resource Type:
Conference
Resource Relation:
Conference: 12. surface modification technologies conference, Chicago, IL (United States), 12-15 Oct 1998; Other Information: PBD: Apr 1998
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 70 PLASMA PHYSICS AND FUSION; CHEMICAL VAPOR DEPOSITION; ELECTRIC CONDUCTIVITY; CALCIUM OXIDES; VANADIUM OXIDES; THERMONUCLEAR REACTOR MATERIALS; VANADIUM BASE ALLOYS; VAPOR DEPOSITED COATINGS; BREEDING BLANKETS

Citation Formats

Park, J H. Electrically insulating films deposited on V-4%Cr-4%Ti by reactive CVD. United States: N. p., 1998. Web.
Park, J H. Electrically insulating films deposited on V-4%Cr-4%Ti by reactive CVD. United States.
Park, J H. 1998. "Electrically insulating films deposited on V-4%Cr-4%Ti by reactive CVD". United States. https://www.osti.gov/servlets/purl/663566.
@article{osti_663566,
title = {Electrically insulating films deposited on V-4%Cr-4%Ti by reactive CVD},
author = {Park, J H},
abstractNote = {In the design of liquid-metal blankets for magnetic fusion reactors, corrosion resistance of structural materials and the magnetohydrodynamic forces and their influence on thermal hydraulics and corrosion are major concerns. Electrically insulating CaO films deposited on V-4%Cr-4%Ti exhibit high-ohmic insulator behavior even though a small amount of vanadium from the alloy become incorporated into the film. However, when vanadium concentration in the film is > 15 wt.%, the film becomes conductive. When the vanadium concentration is high in localized areas, a calcium vanadate phase that exhibits semiconductor behavior can form. The objective of this study is to evaluate electrically insulating films that were deposited on V-4%Cr-4%Ti by a reactive chemical vapor deposition (CVD) method. To this end, CaO and Ca-V-O coatings were produced on vanadium alloys by CVD and by a metallic-vapor process to investigate the electrical resistance of the coatings. The authors found that the Ca-V-O films exhibited insulator behavior when the ratio of calcium concentration to vanadium concentration R in the film > 0.9, and semiconductor or conductor behavior when R < 0.8. However, in some cases, semiconductor behavior was observed when CaO-coated samples with R > 0.98 were exposed in liquid lithium. Based on these studies, they conclude that semiconductor behavior occurs if a conductive calcium vanadate phase is present in localized regions in the CaO coating.},
doi = {},
url = {https://www.osti.gov/biblio/663566}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {4}
}

Conference:
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