The plated metal is copper in color; and
can be deposited matte to very bright . Copper has good corrosion resistance
when used as an undercoat. A number of copper processes are available,
each designed for a specific purpose;
Bright (to eliminate the need
High speed (for electroforming).
Fine grain (to prevent casehardening).
All steel parts having a hardness of
Rockwell C35 and higher shall be baked at 375°F±25F° for
24 hours within 4 hours after plating to provide hydrogen embrittlement
relief. Plated springs and other parts subject to flexure should not be
flexed prior to baking operations.
Class 0: (Unless otherwise specified
.001-.005") For heat treatment stop-off.
Class 1: (.001" minimum thickness)
For carburizing and decarburizing shield, also plated through printed circuit
Class 2: (.0005" minimum thickness)
As an undercoat for nickel and other plating.
Class 3: (.0002" minimum thickness)
To prevent basis metal migration into tin (prevents poisoning of solderability).
Class 4: (.0001" minimum thickness).