Preparation of monolithic AlN and composite TiN-AlN powders and films from precursors synthesized by electrolysis

Aluminum nitride (AlN) and TiAlN precursor solutions were synthesized by room temperature galvanostatic electrolysis of Al metal and Ti-Al alloy, respectively, in isopropyl-amine at a current density of 50 mA cm−2. Monolithic AlN and composite TiAlN powders were prepared from these precursors by two-stage heat treatment at 400 °C in Ar and at 1200 °C in NH3. Nitride films were produced by dip-coating and two-stage heat treatment of the precursor solution on silica glass substrates. The precursor solution used for the film preparation was concentrated from one-third to one-seventh by volume. The powders and films were characterized by XRD, chemical analysis, XPS and SEM/TEM observation in terms of phase evolution, particle size, film thickness and impurity content. The AlN and TiN-AlN films prepared from the concentrated precursor were smooth and flat, and were composed of uniform grains less than 100 nm in size.