METHOD OF PREVENTING ELUTION OF LEAD FROM FAUCET FITTING MADE OF LEAD-CONTAINING COPPER ALLOY

摘要

PROBLEM TO BE SOLVED: To provide a method of preventing the elution of lead to be implemented in order to prevent the elution of the lead into tap water from faucet fittings made of a lead-containing copper alloy having good machinability. SOLUTION: The faucet fittings made of the lead-containing copper alloy are immersed into a neutral, weakly basic or weakly acidic etchant containing a complexing agent having high complex ion formability with the lead, by which the lead particles on the surface are selectively removed. Gas, such as air, containing oxygen or the oxygen is blown into the etchant in order to increase the diffusion rate of the components at the reaction boundary of the lead-containing copper alloy material and the etchant during immersion and to prevent the readhesion of the copper alloy to the treated surface, by which the etchant is stirred. Weak voltage of about -0.3 to +0.2 VvsNHE is recommended to be impressed from outside to the lead-containing copper alloy material as anode for the purpose of oxidizing and dissolving the lead.