How can I Improve adhesion of decorative coating in blind points and corners of brass based faucet?
they do not all have the same preferential growth sites or directions. For example, like in your case, having a good adhesion for the Ni does not mean it will also happen with Cr. What I can advice concerning the Cr deposition is performing a surface pre-treatment prior to electroplating. I am more an expert in plasma pre-treatments but you should consider that this pre-treatment should not alter your faucets topography. This pre-treatment will be like a 'surface activation' that could create nucleation sites for your Cr on top of the desired areas and will enhance Cr adhesion (weak bonds, nucleation,...). I am quite sure that such pre-treatments exist in the literature so you can have a look.
As for TiN deposition by CAPVD, before anything check if your deposition parameters are well optimized. Because generally adhesion problems of PVD coatings come from using non optimized conditions. I can give you an example that I have faced during gold deposition by PVD: the Ar pressure (in plasma) was too low and there were not sufficient reactive species that are bombarding the target, so the film was thin, dense, fragile and with really bad adhesion. When we increased the Ar pressure, the elaborated films were stable, thicker and with really good adhesion even for elecrochemical tests. So you can perform a little parameters optimization to see if your TiN could be more adherent. Another alternative, since your TiN is deposition, is to perform a post-treatment (like annealing for example). Usually I do not support this step because it can oxidize the film (if the annealing is not exempt of O2), it can induce film sintering or cracking and it could also modify the film's cristallinity.