Hydrogen interaction with solid and liquid tin

Abstract

Hydrogen interacts with most metals, and basic thermodynamic parameters enable estimating equilibrium concentration in a wide range of pressures and temperatures. Tin is a common metal whose hydrogen solubility has not been adequately determined yet. A series of solid and liquid tin experiments within the temperature range from 150 to 350 °C exhibit high inertness to hydrogen. Its equilibrium concentration at the melting point of 231.9 °C and 1 bar pressure was below the detection limit of 1 ppb H/Sn. Similarly, the deuterium permeation rate j through the 0.25 mm thick tin membrane at 200 °C was below ∼2.5 × 109 D2/cm2/s, the uncertainty limit due to the isotope exchange reaction forming HD. The main experimental challenges were eliminating weak hydrogen interaction with tin oxide atop the solid and liquid tin and suppressing the setup's hydrogen background outgassing. Tin's inertness to molecular hydrogen may have relevance in some specific technologies. Unfortunately, it has been recently published that tin interacts intensively with hydrogen plasma, which is incompatible with liquid metal divertor demands.