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.