In this article we report on investigations of the nucleation and growth of TiN on tungsten by use of scanning tunneling microscopy (STM) in distilled water. In water tip wear is significantly reduced and the STM images are reproducible by successive scannings. Simultaneous measurements of topography and tunneling barrier signals give new information on material compositions, which is supplementary to the results obtained by transmission electron microscopy and scanning electron microscopy combined with energy dispersive x-ray analysis and Auger electron spectroscopy. The combination of methods give an improved understanding of the nucleation and growth of TiN on W not available by the different methods separately.