Corrosion of Some Pure Metals in Basaltic Lava and Simulated Magmatic Gas at 1150 exp 0 C

摘要

The work summarized was designed to provide an understanding of the reaction mechanisms and modes of degradation of various metals so that the best generic types of alloys can be selected for structural components and instrumentation. Fifteen pure metals were studied. These included base metals such as iron, nickel, and cobalt; some precious metals: platinum, rhodium and palladium (possible thermocouple or lead wire materials); refractory metals: tungsten, molybdenum, tantalum, niobium, vanadium, rhenium; plus other high melting metals such as titanium and zirconium. Samples were exposed to basaltic lava at 1150 exp 0 C for periods of 24 and 96 hours. A cover gas was used to produce oxygen and sulfur fugacities corresponding to those of the gases dissolved in basaltic melts. The corrosion behavior is described. Extensive analyses of the reaction products by scanning electron microscopy, x-ray energy dispersive analysis, electron microprobe analysis, and metallography are presented for each metal. The products formed are discussed with reference to thermodynamic stability diagrams, and the reaction path concept is used to explain some of the corrosion product morphologies. (ERA citation 05:011785)