Hydrogen Permeation through Iron, Nickel, and Heat Resisting Alloys at Elevated Temperatures

Abstract

Hydrogen permeability of several metals and alloys was measured in the temperature range between 200 and 1 OOOC and some factors affecting the hydrogen permeability were discussed. Materials studied were iron, nickel, BONi-20Cr alloy, 50Fe-30 li-20Cr alloy, HK 40, Incoloy BOO, H astelloy X , and fnc onel 600. The hydrogen permeability of nickel was proportional to the square root of the p ressure and inversely jJroportional to the membrane thickness . The activation energy and pre-exponential factor for the hy drogen permeation through these metals and alloys were derived from the temperature codficient. The hydrogen permeability of nickel was larger than that of iron (r) , and the permeabilities of the heat resisting alloys were between those of nickel and iron (r). There was a close correlation between the hydrogen permeability and nickel conlent in the alloys, tha t is, the permeability increased with the increase of the nickel content in the alloys. The formatioll of the oxide film on the alloy surface in wet hy drogen resulted in a remarkable reduction rif the hy drogen permeability at elevated temperatures.