Combinations of physically vapour deposited (PVD) coatings and electro
plated layers are widely used for decorative applications. The electro
plated layer beneath the PVD coating acts as a diffusion barrier. Conv
entionally electroplated barrier layers make use of nickel which has t
o be replaced in allergy-free systems by for example Ni/NiPd and CuSn(
Zn). The PVD coating has to meet a variety of requirements: attractive
colour, high wear resistance and good corrosion resistance. Within th
e scope of the search for new colours a number of nitrides of binary I
Va metal-based alloys such as (Ti,V)N, (Zr,V)N, (Zr,Al)N, (Zr,Cr)N, (Z
r,Y)N were deposited by reactive magnetron sputtering. To describe the
colour the CIE La*b* system was used. Spectroscopic ellipsometry (SE
) was introduced to determine material related parameters. In general,
both the stoichiometry and the structure can influence the colour of
a coating. The correlation between colour, stoichiometry and structure
was determined by surface analytical methods (glow discharge optical
spectroscopy, Auger electron spectroscopy, X-ray diffraction). Proper
selection of process parameters (target composition, N2 flow rate, etc
.) results in coatings with colours exceeding the conventional spectru
m of decorative coatings. As an example of structural and stoichiometr
ic influences on colour, ZrN and (Zr,Y)N coatings are discussed.