Microbalance study of the corrosion kinetics of lithium hydride by water

The corrosion kinetics of commercial LiH powder (∼100 μm, Alfa Aesar) by gaseous water in a humidified nitrogen stream was found to be constant in time and first order in gas phase water (<1% relative humidity). Data obtained using a customized microbalance system equipped with a precision water saturator, dew point analyzer, and magnetic sectoring mass spectrometer were used to derive a rough empirical rate expression for the corrosion of the powder by water at low (0.1-0.9%) RH values. The present data are consistent with two models: (i) the tri-layer model [J. Phillips, J. Tanski, Int. Mater. Rev. 50 (2005) 265], and (ii) rate control by diffusion through a barrier layer.