About electroplating, electroplating color preservation and other questions?

1. All stainless steel of our company uses PVD plating, and there is no problem in normal use for 3 years;
2 copper silver is water plated, color preservation is not stainless steel long;
3. At present, the thickness of PVD and water plating in our company is 0.03~0.05u, and both PVD and water plating can be added
Thick plating, thick plating can be 0.05~0.1u;
4. Vacuum plating can be plated 14K,18K,24K, black, silver, rose gold (and color plate color)