Patent ID: 6270590
Filing Date: 2001-08-07
Classification: C23F,E03B,Y10S

Abstract:
A method for treating a metal for use in water distribution, said method comprising the steps of:(i) providing a water distribution component comprising a copper-based alloy containing lead as an alloy element a portion of the lead being segregated in a plurality of discrete concentrations at a surface of the water distribution component in the form of lead or lead salts;(ii) etching the surface of the component selectively to remove almost entirely the Pb and Pb salts from the surface, said etching comprising treating said surface with an acidic aqueous solution selected from the group consisting of a) a non-oxidizing acidic aqueous solution comprising an acid capable of forming soluble Pb salts and, b) an oxidizing acidic aqueous solution comprising an organic acid mixed with peroxide; and(iii) passivating said etched surface whereby to inhibit release of any Pb or Pb salts remaining in the component when the passivated surface is in contact with water.