Harald Hantsche

Decorative properties and chemical composition of hard coatings

Transition metal compounds (nitrides, carbides, etc.) find increasing use as decorative coatings combining intensive colours, high wear resistance and good corrosion resistance. While golden TiN and dark-grey TiC are limited in their colour variation, the addition of a second metal or a second metalloid widens the spectrum of decorative colours, e.g. to dark blue with (Ti, Al)N. In the search for new colours, a number of nitrides of binary IVa metal-based alloys were deposited by reactive magnetron sputtering. The correlation between colour and stoichiometry was determined by surface analytical methods. Proper selection of the process parameters (target composition, N2 flow rate, etc.) results in coatings with different colours exceeding the conventional spectrum of decorative coatings.