Having 2 different substrates under the same deposit conditions (TiN coating) why it is possible to obtain different colours in the 2 dif substrates?

Coating is made by same deposit conditions. substrates are HSS Drill bit and Shim SS 300 series. On the drill bit we are getting some golden color, however on the shim we got no color it is like...

09 February 2021 9,515 7 View