Sulfur-rich corrosion-resistant copper-zinc alloy

Abstract

Copper-zinc alloys exhibiting enhanced oxidation resistance are provided by adding an amount of sulfur that is effective to enhance oxidative resistance. Such sulfur addition can be achieved by forming a sulfur-rich pre-mix that is added to a base alloy composition. This technique provides improved homogeneity and distribution of the sulfur predominantly in the form of a metal sulfide.

What is claimed is: 
     
         1 . A copper-zinc alloy having an elemental composition comprising:
 from about 10% to about 45% zinc by weight;   at least 50% copper by weight; and   an amount of sulfur that is effective to enhance oxidative resistance.   
     
     
         2 . An alloy according to  claim 1 , in which the sulfur is present in the form of a sulfide chosen from the group comprising zinc-sulfide, copper-sulfide, and a combination thereof. 
     
     
         3 . An alloy according to  claim 2 , in which the sulfide is homogenously distributed throughout the alloy. 
     
     
         4 . An alloy according to  claim 1 , in which the element zinc is present in an amount from about 10% to about 40% by weight. 
     
     
         5 . An alloy according to  claim 1 , in which the element zinc is present in an amount form about 35% to about 45% by weight. 
     
     
         6 . An alloy according to  claim 1 , further comprising one or more additives selected from the group consisting of silicon, selenium, tellurium, lead, tin, manganese, bismuth, antimony, phosphorous, iron, nickel, aluminum, and arsenic, each of the one or more additives present in an amount of from about 0.006% to about 6% by weight. 
     
     
         7 . An alloy according to  claim 1 , in which the sulfur is present in an amount that is between about 0.006% and about 4% by weight. 
     
     
         8 . An alloy according to  claim 1 , in which the sulfur is present in an amount of from about 2.1% to about 4% by weight. 
     
     
         9 . An alloy according to  claim 1 , in which the sulfur is present in an amount of from about 0.006% to about 2.0% by weight. 
     
     
         10 . An alloy according to  claim 1 , in which the sulfur is present in an amount of from about 0.006% to about 0.10% by weight. 
     
     
         11 . An alloy according to  claim 1 , in which the sulfur is predominantly present in the form of an intermetallic sulfide. 
     
     
         12 . A water-conveying conduit system comprising:
 a conduit component fabricated from a copper-zinc alloy according to  claim 1 .   
     
     
         13 . A process for preparing an oxidation resistant copper-zinc alloy, comprising:
 combining sulfur and a pre-mix metal under conditions to form a molten alloy pre-mix, wherein the pre-mix metal is chosen from the group consisting of copper, zinc, aluminum, lead, bismuth, tin, and a combination thereof;   preparing a base alloy; and   combining the alloy pre-mix and the base alloy.   
     
     
         14 . A process according to  claim 13 , wherein the pre-mix metal comprises zinc. 
     
     
         15 . A process according to  claim 13 , wherein the pre-mix metal comprises copper. 
     
     
         16 . A process according to  claim 15 , wherein the pre-mix metal further comprises aluminum. 
     
     
         17 . A process according to  claim 16 , wherein the pre-mix metal further comprises tin and lead. 
     
     
         18 . A process according to  claim 13 , wherein the base alloy comprises copper. 
     
     
         19 . A process according to  claim 13 , wherein the base alloy comprises zinc. 
     
     
         20 . A process according to  claim 19 , wherein the base alloy further comprises copper. 
     
     
         21 . A process according to  claim 13 , in which the resulting alloy is solidified and subsequently heat treated to enhance machinability.