Development of electrically insulating coatings for service in a lithium environment

[摘要] Several experiments were conducted to develop electrically insulating CaO coatings on a V-4Cr-4Ti alloy for application in a Li environment. The coatings were developed by vapor-phase transport external to Li, and also in situ in a Li-Ca environment at elevated temperature. In the vapor-phase study, several geometrical arrangements were examined to obtain a uniform coating of Ca on the specimens, which were typically coupons measuring 5 to 10 x 5 x 1 mm(3). After Ca deposition from the vapor phase, the specimens were oxidized in a high-purity argon environment at 600 degreesC to convert the deposited metal into oxide. The specimens exhibited insulating characteristics after this oxidation step. Several promising coated specimens were then exposed to high-purity Li at 500 degreesC for 48-68 h to determine coating integrity. Microstructural characteristics of the coatings were evaluated by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis. Electrical resistances of the coatings were measured by a two-probe method between room temperature and 700 degreesC before and after exposure to Li. (C) 2000 Elsevier Science B.V. All rights reserved.

[发布日期] 2000-12-01

[效力级别]  Proceedings Paper