High pressure/high temperature hydrogen permeability in candidate Stirling engine alloys

摘要: Hydrogen permeation tests of eight high-temperature engineering alloys were conducted in 20.7 MPa hydrogen at 923 to 1088 K for assessing suitability Stirling engine application heater head and tubing. A specially designed balancedpressure reactor was built this purpose test materials over a wide temperature range. The results show that alloy 19-9DL had the best overall performance both diffusion properties. Alloys N-155, IN 800, A-286 properties slightly inferior higher temperatures, but lower temperatures N-155 significantly coefficients than 800. Solubility 19-9DL, similar; with 800 A-286, solubility seems decrease increasing temperature. For tubes, appears be most suitable material based on its low permeability rates. activation energies compared well available literature data. No correlation noted between chemistry—specifically levels interstitial elements such as carbon boron, hydride forming Cb, Ta, Ti, V—and permeation/diffusion/solubility.