Development of electrical insulator coatings for liquid-metal blanket applications
Based on a preliminary survey of more than 15 oxides and nitrides, four ceramic materials (CaO, MgO, Y{sup 2}O{sup 3}, and BN) were identified as candidates for insulator coating development. These compounds were fabricated by various techniques and exposed to flowing Li at 400-410{degrees} to assess chemical compatibility. Yttrium oxide exhibited excellent corrosion resistance in flowing liquid Li at 400{degrees}C; its corrosion rate was calculated to be 0.042 {mu}m/hr. Resistivity measurements by a standard four-probe method on Y{sup 2}O{sup 3} in air at temperatures between {approximately}450 and 1000{degrees}C, before and after exposure to Li for 675 h at 410{degrees}C, indicated no deterioration in resistivity. The resistivity of in-situ-formed (V,Ti){sup x}N reaction-product layers on V-20Ti and TiN on Ti was determined at room temperature and 80{degrees}C by a two-probe method. The resistivity of the film on the V-20Ti alloy was low ({approximately}20 {Omega}m) and the film on Ti exhibited metallic conduction. Adhesion bonding between Y{sup 2}O{sup 3} and Y, V, Ti, Y, V-20Ti, V-3Ti-1Si, and Types 304 and 316 stainless steel was investigated in reducing and oxidizing gaseous environments at 927{degrees}C. Except for the V-20Ti alloy, the V-base alloys, Ti, and Type 304 stainless steel were well bonded to Y{sup 2}O{sup 3} in the reducing atmosphere. In the oxidizing atmosphere, bond regions of Types 304 and 316 stainless steel were better than in the reducing atmosphere because of reaction between the oxide scale on the steels (Cr{sup 2}O{sup 3}) and Y{sup 2}O{sup 3} to form YCrO{sup 3}. Neither V, Ti, nor the V-alloys bonded with Y{sup 2}O{sup 3}. These results suggest that a low-melting eutectic layer forms between Y{sup 2}O{sup 3} and the oxides layers present on V, Ti, and V-alloys.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- OSTI ID:
- 139234
- Report Number(s):
- DOE/ER-0313/13; ORNL/M-2722; ON: DE93013462; TRN: 93:001624-040
- Resource Relation:
- Other Information: PBD: [1992]; Related Information: Is Part Of Fusion reactor materials semiannual progress report for period ending September 30, 1992; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
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Strength, ductility, and ductile-brittle transition temperature for MFR (magnetic fusion reactor) candidate vanadium alloys
Related Subjects
36 MATERIALS SCIENCE
BREEDING BLANKETS
PROTECTIVE COATINGS
THERMONUCLEAR REACTORS
OXIDES
NITRIDES
YTTRIUM
CORROSION RESISTANCE
ADHESION
BONDING
TEMPERATURE RANGE 0400-1000 K
CALCIUM OXIDES
MAGNESIUM OXIDES
YTTRIUM OXIDES
BORON NITRIDES
LITHIUM
ELECTRIC CONDUCTIVITY
TITANIUM
VANADIUM BASE ALLOYS
TITANIUM ALLOYS
VANADIUM
YTTERBIUM
SILICON ALLOYS
STAINLESS STEEL-304
STAINLESS STEEL-316
THERMONUCLEAR REACTOR MATERIALS
ELECTRICAL INSULATORS
PROGRESS REPORT