Low mist chromium plating method and system
AssigneeOptical Radiation Corporation
InventorDon Dupree
Life of this patent
Estimating the term…
Abstract
A low mist chromium plating system is disclosed which comprises a closed plating tank containing chromium plating solution preferably covered by a layer of mist suppressing foam. Nitrogen carrier gas is introduced into the plating tank above the plating solution and carries chromium mist to a series of aqueous traps. The first trap contains sodium bisulfite for reducing hexavalent chromium ions to trivalent chromium ions. The last trap contains 1,5-diphenylcarbohydrazide for indicating the presence of hexavalent chromium.
Claims18
A plating system for reducing the amount of plating solution mist escaping into the atmosphere comprising:
- a plating tank for containing a metal plating solution and at least one anode;
- a cover for removably sealing the plating tank;
- means for establishing a current between a cathode and an anode submersed in a plating solution contained in the plating tank;
- means for introducing a carrier gas into the sealed plating tank above a plating solution contained in the plating tank;
- a first aqueous trap comprising a container for containing an aqueous rinse;
- means for passing carrier gas and plating solution mist from the sealed plating tank to the trap and for bubbling said carrier gas and plating solution mist through aqueous rinse contained in said trap;
- and
- means for preventing current from passing between a substrate and anode submerged in a plating solution contained in the plating tank unless the plating tank is covered and sealed.
A plating system for reducing the amount of plating solution mist escaping into the atmosphere comprising:
- a plating tank for containing a metal plating solution and at least one anode;
- a cover for establishing a current between a cathode and an anode submersed in a plating solution contained in the plating tank;
- means for introducing a carrier gas into the sealed plating tank above a plating solution contained in the plating tank;
- a first aqueous trap comprising a container for containing an aqueous rinse;
- means for passing carrier gas and plating solution mist from the sealed plating tank to the trap and for bubbling said carrier gas and plating solution mist through an aqueous rinse contained in said trap;
- and
- means for preventing the opening of the cover for a predetermined period of time after the passage of current between an anode and cathode submerged in plating solution contained in the plating tank.
A method for reducing the amount of plating solution mist escaping into the atmosphere comprising:
- providing a plating tank containing a metal plating solution and at least one anode;
- immersing a substrate to be plated into the plating solution;
- covering and sealing the plating tank with a removable cover;
- establishing a current between the substrate and the anode to thereby electrolytically deposit metal onto the substrate for a select period of time;
- introducing a carrier gas into the covered plating tank above the surface of the plating solution;
- passing carrier gas containing mist of the plating solution from the plating tank to an aqueous rinse and bubbling said carrier gas containing mist of the plating solution through the aqueous rinse;
- and
- covering the plating solution with a mist suppressing foam.
A method for reducing the amount of hexavalent chromium escaping into the atmosphere above a chromium plating solution comprising:
- providing a plating tank containing a chromium plating solution and an anode;
- immersing a substrate to be plated into the plating solution;
- covering and sealing the plating tank with a removable cover;
- establishing a current for a select period of time between the substrate and the anode to thereby electrolytically deposit chromium onto the substrate;
- introducing a carrier gas into the covered plating tank over the surface of the plating solution;
- and
- passing carrier gas containing mist of the chromium plating solution from the plating tank to a first trap comprising aqueous solution containing a reducing agent for reducing hexavalent chromium ions to trivalent chromium ions and bubbling said carrier gas containing chromium mist through said aqueous solution.
Dependencies are inferred from the claim text.