In-situ infrared imaging methodology for measuring heterogeneous growth process of a hydride phase

In the paper we report on a new methodology, which allows measuring in-situ heterogeneous growth rates of hydride phase in films during metal-hydride phase transformation. This optical method is based on infrared imaging of a wedge-shaped thin film during hydrogen loading. In the paper the method is demonstrated for Mg 98.4Ti 1.6 wedge-shaped thin film and main conclusions are supported by results of transmission electron microscopy. The methodology combined with the structural characterizations verified fast formation of MgH 2 layer on top followed by drastically slower growth of the MgH 2 phase. The initial averaged growth rate of the MgH 2 phase was estimated as ∼1.3 nm/s, and as ∼0.03 nm/s subsequently.