DEVELOPMENT OF HIGH TEMPERATURE ALKALI METAL RESISTANT INSULATED WIRE.

Abstract : This report covers effort directed toward the development of an insulated electrical 1onductor resistant to saturated potassium (850 C) and mercury (538 C) vapors. Thirty-three samples were exposed to potassium vapor at 850 C. Six samples were exposed to mercury vapor at 540 C. Preformed coils of nickel clad silver were coated with molybdenum and nickel aluminide respectively by plasma-arc spraying techniques. These coils were then insulated by plasma-arc sprayed coatings of zirconia (99%), followed by high purity alumina (98%). Vibration, shock, acceleration, and humidity tests were conducted on these insulation combinations in a statorette. These tests were successfully passed by the insulated wire. An attempt was made to measure the leakage resistance of a sapphire to tantalum seal while the seal was exposed to potassium vapor at 850 C. This attempt was partially successful. The results of this test indicate potassium vapor at 850 C will not act as a conductor. (Author)