Nickel plated zinc alloys for coinage
AssigneeArtazn LLC.
InventorsWilliam L. Rauch, Carl R. DelSorbo, Randy Beets
Life of this patent
Estimating the term…
Abstract
A lower melting point metal substrate such as zinc is covered with a higher melting point metal layer such as nickel. In order to render the nickel layer suitable for coining without cracking, it is quickly annealed with a burst of induction heat. The induction heat is limited so that only the metal layer is heated without allowing substantial heat transfer to the metal substrate. This protects the metal substrate from any substantial melting, deformation or warping and maintains the metal substrate substantially intact and without a change in properties and shape.
Claims14
A method of making a plated zinc planchet, comprising:
- plating a higher melting point metal layer comprising nickel, bronze, or brass over a lower melting point metal substrate consisting of zinc or a zinc alloy;
- and
- heating said higher melting point metal layer with a burst of predetermined amount of induction heat sufficient to anneal at least a portion of said higher melting point metal layer so as to limit heat transfer from said higher melting point metal layer to said lower melting point metal substrate so as to substantially avoid melting of said lower melting point metal substrate to form a plated zinc planchet that is suitable for a coining operation, wherein the burst of predetermined amount of induction heat is sufficient to anneal the at least a portion of said higher melting point metal layer to a temperature of more than 1000° F.
Dependencies are inferred from the claim text.