Need help with Titanium Nitride TiN coatings

A. Yes, it is difficult to coat TiN on glass whereas it is straightforward to deposit Ti on it. My experience is that immediately after coating TiN looks beautiful on glass. But pretty soon it shrinks, cracks and crumbles into tiny flakes. I guess it is due to built in stresses both in glass and TiN and a mismatch in the crystalline properties. In fact it is not possible to deposit even gold directly on glass. But commercially it ( I.e TiN as well gold) is routinely done. I think one could try the following:
1. Pay utmost attention to pre cleaning and in situ cleaning and ion etching.
2. I don't know the technique you are using for depositing TiN. Unbalanced magnetron might be more suitable than others.
3. An inter layer of either Cr or Ti helps in depositing gold on glass. You may try this. I use cathodic arc technique. Ti inter layer was not of any help. But there are a number of factors.
4. It may also depend on the type of glass one uses. I guess it would be much easier to coat on quartz because of its crystalline properties.
5. Deposition temperature is another important factor.

Good luck! Please share your experience.

A. I don't have any ready-made answer. You have a really big machine. I don't know what is the glass object you are trying to coat, configuration of the machine, purpose of coating, your current cleaning steps etc. However you cannot apply a DC bias to glass as it is not electrically conducting. In principle one can apply RF bias. But it may not be practical in such a big machine. You may perhaps generate a glow discharge using the DC supply and expose the glass objects to the plasma thus generated before coating TiN. The manufacturers of the machine could be of some help.

A. Often a cathodic arc tends to go off and the machine is designed to automatically re-trigger it. It depends on the nature of the target material, operating conditions like gas, pressure, current, target condition etc. It would be a problem if it happens too (?) frequently. It could also be indicating that the target is worn out and a replacement is required. The operator has to develop an instinct for these things !

A. Experience is the best teacher. Take out the magnet and see what happens. It may also be useful to read some literature on cathodic arc coating. Google search will yield plenty of references.