Minimum nickel electroplate thickness for bright finish

I would like to know if there is a minimum thickness neccessary for a nickel electroplate over a copper alloy substrate in order to obtain a bright finish, and the same for a semi-bright finish. Also, if there is an ASTM standard or similar that defines what is a bright, semi-bright and dull nickel electroplate. Thank you for your help.

Eduardo,

Thickness is only one of the variables which help determine brightness of a nickel deposit. Some other variables are:
Primary Brightener
Secondary Brightener
Leveling (leveler)
Brightness/refelectivity of substrate
Operating temperature, etc.
In general, a bright nickel plating solution operated at the proper parameters of all of the above will show more leveling with greater time up to a point. This leveling action is the ability to fill scratches. The reflectivity and refraction of light is changed by this leveling and more of it is perceived as a brighter finish. (a simplification). Semi bright can mean many things. Is it a finish "look" you desire or is it part of duplex or triplex nickel? If it is part of a multilayer nickel, it is the structure of the deposit which is of importance not the brightness.

I suggest that you read up a bit on the subject of bright nickel plating so that you can ask the proper questions of your supplier.