Nanocrystalline diamond films, as other forms of diamond, possess a set of extreme properties, such as high thermal conductivity, hardness and resistance to hazard environments. Although an enormous focus has been placed into the deposition of nanocrystalline diamond films, most of this research uses microwave plasma assisted CVD systems. However, the growth conditions used in microwave systems cannot be directly used in hot-filament CVD systems. In this paper, it is meant to enlarge the knowledge of the process of depositing nanocrystalline films on different engineering materials, by means of hot-filament CVD systems. The coated materials include silicon (Si); titanium (Ti); tungsten carbide with cobalt as binder (WC-Co); and tungsten carbide with nickel as binder (WC-Ni). On the former two substrates, the diamond films were achieved on the bare substrates and with the use of an interlayer. The interlayers used were chromium nitride (CrN) and titanium aluminium nitride (TiAlN). Additionally, the as-grown films were characterized for hardness, quality and microstructure using scanning electron microscopy, Raman spectroscopy and nanohardness testing.