Method of reducing elution of lead in lead-containing copper alloy, and drinking water service fittings made of lead-containing copper alloy

Abstract

It is an object of the present invention to provide a processing method for preventing elution of lead in a lead-containing copper alloy to prevent lead from eluting from a faucet metal, etc. made of a lead-containing copper alloy, and a drinking water service fitting made of a lead-containing copper alloy in which elution of lead has been prevented. By forming a chromate film on the surface of a lead-containing copper alloy material, it is possible to reduce elution of the lead left in a limited amount on the surface. A drinking water service fitting made of a lead-containing copper alloy is immersed in an alkaline etching solution in a pre-processing step for a nickel chromium plating step to selectively remove lead on the surface of the lead-containing copper alloy material and is then activated in a solution such as sulfuric acid and hydrochloric acid. Nickel plating is subsequently effected, and then chromium plating is effected in a sargent chromium or chromium fluoride bath, and a chromate film may be formed by immersing the drinking water service fitting in a chromate solution.

What is claimed is:  
     
         1 . (Amended) A processing method of reducing elution of lead from a lead-containing copper alloy, characterized by the step of immersing the lead-containing copper alloy in an alkaline etching solution to which an oxidant has been added to remove lead on the surface thereof.  
     
     
         2 . (Amended) A processing method of reducing elution of lead from a lead-containing copper alloy according to  claim 1 , wherein either one of an oxidant or a chelating agent, or both, are added to the alkaline etching solution.  
     
     
         3 . (Amended) A processing method of reducing elution of lead from a lead-containing copper alloy, characterized by the step of immersing the lead-containing copper alloy in chromic acid solution to which fluoride has been added to remove lead on the surface thereof.  
     
     
         4 . (Deleted)  
     
     
         5 . (Amended) A processing method of reducing elution of lead from a lead-containing copper alloy, characterized by the step of immersing the lead-containing copper alloy in a chromate solution to which phosphoric acid has been added to form a chromate film on the surface thereof.  
     
     
         6 . (Deleted)  
     
     
         7 . (Amended) A processing method of reducing elution of lead from a lead-containing copper alloy, characterized by the step of immersing the lead-containing copper alloy in an alkaline etching solution to remove lead on the surface thereof, and subsequently immersing the same in a chromic solution to which fluoride has been added to remove lead on the surface thereof.  
     
     
         8 . (Amended) A processing method of reducing elution of lead from a lead-containing copper alloy, characterized by the step of immersing the lead-containing copper alloy in an alkaline etching solution to which an oxidant has been added to remove lead on the surface thereof, and subsequently immersing the same in a chromate solution to form a chromate film on the surface thereof.  
     
     
         9 . (Amended) A processing method of reducing elution of lead from a lead-containing copper alloy, characterized by the step of immersing the lead-containing copper alloy in chromic acid to which fluoride has been added to remove lead on the surface, and subsequently immersing the same in a chromate solution to form a chromate film on the surface thereof.  
     
     
         10 . (Amended) A processing method of reducing elution of lead from a lead-containing copper alloy, characterized by the step of immersing the lead-containing copper alloy in an alkaline solution to selectively remove lead on the surface thereof, and then immersing the same in chromic acid solution to remove further lead on the surface thereof, and subsequently immersing the same in a chromate solution to which phosphoric acid has been added to form a chromate film on the surface thereof.  
     
     
         11 . (Deleted)  
     
     
         12 . (Amended) A drinking water service fitting made of a lead-containing copper alloy, characterized by the step of immersing a lead-containing copper alloy material in an alkaline etching solution to which an oxidant has been added to remove lead on the surface thereof.  
     
     
         13 . (Amended) A drinking water service fitting made of a lead-containing copper alloy, characterized by the step of immersing a lead-containing copper alloy material in a chromic acid solution to which fluoride has been added to remove lead on the surface thereof.  
     
     
         14 . (Amended) A drinking water service fitting made of a lead-containing copper alloy, characterized by the step of immersing a lead-containing copper alloy material in a chromate solution to which phosphoric acid has been added to form a chromate film on the surface thereof.  
     
     
         15 . (Amended) A drinking water service fitting made of a lead-containing copper alloy, characterized by the step of immersing a lead-containing copper alloy material in an alkaline etching solution to which an oxidant has been added to remove lead on the surface thereof, and subsequently immersing the same in a chromate solution to form a chromate film on the surface thereof.  
     
     
         16 . (Amended) A drinking water service fitting made of a lead-containing copper alloy, characterized by the step of immersing a lead-containing copper alloy material in an alkaline etching solution to remove lead on the surface thereof, and subsequently immersing the same in a chromic acid solution to which fluoride has been added to remove lead on the surface thereof.  
     
     
         17 . (Amended) A drinking water service fitting made of a lead-containing copper alloy, characterized by the step of immersing a lead-containing copper alloy material in a chromic acid solution to which fluoride has been added to remove lead on the surface thereof, and subsequently immersing the same in a chromate solution to form a chromate film on the surface thereof.  
     
     
         18 . (Amended) A drinking water service fitting made of a lead-containing copper alloy, characterized by the step of immersing a lead-containing copper alloy material in an alkaline solution to remove lead on the surface thereof, and then immersing the same in a chromic acid solution to remove lead on the surface thereof, and subsequently immersing the same in a chromate solution to which phosphoric acid has been added to form a chromate film on the surface thereof.  
     
     
         19 . (Added) A plating method of reducing elution of lead from a lead-containing copper alloy for plating the outer surface of the lead-containing copper alloy and at the same time, removing lead on the inner surface thereof.  
     
     
         20 . (Added) A plating method of reducing elution of lead from a lead-containing copper alloy according to  claim 19 , wherein chromium plating is effected after nickel plating.  
     
     
         21 . (Added) A plating method of reducing elution of lead from a lead-containing copper alloy according to claims  19  and  20 , wherein an oxidant is contained in an alkaline degreasing solution for a cleaning step before plating.  
     
     
         22 . (Added) A plating method of reducing elution of lead from a lead-containing copper alloy according to  claim 20 , wherein fluoride is contained in a plating solution for chromium plating.  
     
     
         23 . (Added) A plating method of reducing elution of lead from a lead-containing copper alloy according to claims  19  and  20 , wherein the lead-containing copper alloy is immersed in a chromate solution after plating the outer surface thereof to form a chromate film on the inner surface thereof.  
     
     
         24 . (Added) A plating method of reducing elution of lead from a lead-containing copper alloy according to claims  19  and  20 , wherein the lead-containing copper alloy is immersed in an alkaline degreasing solution for a cleaning step before plating in which an oxidant is contained, and plating is effected, after nickel plating, in a chromium plating solution in which fluoride is contained.  
     
     
         25 . (Added) A drinking water service fitting made of a lead-containing copper alloy, characterized by the step of plating the outer surface of the lead-containing copper alloy and at the same time, removing lead on the inner surface thereof.  
     
     
         26 . (Added) A drinking water service fitting made of a lead-containing copper alloy according to  claim 25 , wherein chromium plating is effected after nickel plating.  
     
     
         27 . (Added) A drinking water service fitting made of a lead-containing copper alloy according to claims  25  and  26 , wherein an oxidant is contained in an alkaline degreasing solution for a cleaning step before plating.  
     
     
         28 . (Added) A drinking water service fitting made of a lead-containing copper alloy according to  claim 26 , wherein fluoride is contained in a plating solution for chromium plating.  
     
     
         29 . (Added) A drinking water service fitting made of a lead-containing copper alloy according to claims  25  and  26 , wherein the lead-containing copper alloy is immersed in a chromate solution after plating the outer surface thereof, to form a chromate film on the inner surface thereof.  
     
     
         30 . (Added) A drinking water service fitting made of a lead-containing copper alloy according to claims  25  and  26 , wherein the lead-containing copper alloy is immersed in an alkaline degreasing solution for a cleaning step before plating in which an oxidant is contained, and chromium plating is effected, after nickel plating, in a chromium plating solution in which fluoride is contained.  
     
     
         31 . (Added) A plating method of reducing elution of lead from a lead-containing copper alloy according to claims  19  and  20 , wherein the lead-containing copper alloy is immersed in an alkaline degreasing solution for a cleaning step before plating in which an oxidant is contained, and plating is effected, after nickel plating, in a chromium plating solution in which fluoride is contained, and the lead-containing copper alloy is subsequently immersed in a chromate solution to form a chromate film on the inner surface thereof.  
     
     
         32 . (Added) A drinking water service fitting made of a lead-containing copper alloy according to claims  25  and  26 , wherein the lead-containing copper alloy is immersed in an alkaline degreasing solution for a cleaning step before plating in which an oxidant is contained, and plating is effected, after nickel plating, in a chromium plating solution in which fluoride is contained, and the lead-containing copper alloy is subsequently immersed in a chromate solution to form a chromate film on the inner surface thereof.  
     
     
         33 . (Added) A plating method of reducing elution of lead according to claims  19  and  20 , wherein phosphoric acid is contained in a chromate solution.  
     
     
         34 . (Added) A plating method of reducing elution of lead according to claims  25  and  26 , wherein phosphoric acid is contained in a chromate solution, and a drinking water service fitting made of a lead-containing copper alloy available from the plating method.