Production Strategies of TiN(x) Coatings via Reactive High Power Impulse Magnetron Sputtering for Selective H(2) Separation

This scientific work aims to optimize the preparation of titanium nitride coatings for selective H(2) separation using the Reactive High Power Impulse Magnetron Sputtering technology (RHiPIMS). Currently, nitride-based thin films are considered promising membranes for hydrogen. The first series of TiN(x)/Si test samples were developed while changing the reactive gas percentage (N(2)%) during the process. Obtained coatings were extensively characterized in terms of morphology, composition, and microstructure. A 500 nm thick, dense TiN(x) coating was then deposited on a porous alumina substrate and widely investigated. Moreover, the as-prepared TiN(x) films were heat-treated in an atmosphere containing hydrogen in order to prove their chemical and structural stability; which revealed to be promising. This study highlighted how the RHiPIMS method permits fine control of the grown layer’s stoichiometry and microstructure. Moreover, it pointed out the need for a protective layer to prevent surface oxidation of the nitride membrane by air and the necessity to deepen the study of TiN(x)/alumina interface in order to improve film/substrate adhesion.