Lead-free alloys, composition thereof, methods of preparation and uses for soldering and babbitting

Abstract

Lead-free alloys comprising tin, copper, antimony, silver and a lanthanide metal are disclosed. Also disclosed are methods of preparing the lead-free alloys and their use for soldering and babbitting. The lead-free solder alloys exhibit improved tensile and shear strength, and they exhibit flow characteristics similar to those of 50:50 tin:lead alloys.

We claim:  
     
         1 . A lead-free solder alloy useful for plumbing, refrigeration, and roofing applications, wherein the alloy comprises tin, antimony, copper, silver, and a lanthanide metal; and the alloy is substantially free of group IVa elements, group Va elements, bismuth, nickel, and zinc.  
     
     
         2 . The lead-free alloy of  claim 1 , wherein the lanthanide metal is selected from the group consisting of lanthanum, cerium, neodynium, samarium, europium and mixtures thereof.  
     
     
         3 . The lead-free alloy of  claim 2 , wherein the alloy comprises at least 96 wt. % tin, 0.25 to 1 wt. % antimony, 1 to 4 wt. % copper, 0.05 to 0.5 wt. % silver and 0.1 to 0.3 wt. % lanthanide metal.  
     
     
         4 . The lead-free alloy of  claim 3 , wherein the lanthanide metal content is 0.03% to 0.1 wt. % based on the weight of the alloy.  
     
     
         5 . The lead-free alloy of  claim 2 , wherein the lanthanide metal is cerium.  
     
     
         6 . The lead-free alloy of  claim 5 , wherein the alloy comprises at least 96 wt. % tin, 0.25 to 1% wt. % antimony, 1 to 4 wt. % copper, 0.05 to 0.5 wt. % silver, and 0.01 to 0.3 wt. % cerium.  
     
     
         7 . The lead-free alloy of  claim 6 , wherein the cerium content is 0.03% to 0.1 wt. % based on the weight of the alloy.  
     
     
         8 . The lead-free alloy of  claim 7 , wherein the melting range is from about 190° C. to about 300° C.  
     
     
         9 . The lead-free alloy of  claim 8 , wherein the melting range is from about 210° C. to about 280° C.  
     
     
         10 . A lead-free solder alloy useful for plumbing, refrigeration, and roofing applications wherein the alloy consists essentially of tin, antimony, copper, silver, and cerium; and the alloy is substantially free of group IVa elements, group Va elements, bismuth, nickel, and zinc.  
     
     
         11 . A method of preparing a lead free-alloy useful for plumbing, refrigeration, and roofing applications comprising: 
 preparing a molten first alloy comprising tin, antimony and copper;    adding a lanthanide-containing second alloy to the molten first alloy to form a molten lead-free alloy;    processing the molten lead-free alloy into a shape; and    cooling the lead-free alloy to form a solid form of said shape; wherein    the lead-free alloy is substantially free of group IVa elements, group Va elements, bismuth, nickel and zinc.    
     
     
         12 . The lead-free alloy of  claim 11 , wherein the lanthanide metal is selected from the group consisting of lanthanum, cerium, neodynium, samarium, europium and mixtures thereof.  
     
     
         13 . The method of  claim 12 , wherein the lanthanide metal is cerium.  
     
     
         14 . The method of  claim 12 , wherein the first alloy is prepared from 1.5 to 6 parts by weight copper, 0.5 to 2 parts by weight antimony, and 92 to 98 parts by weight tin.  
     
     
         15 . The method of  claim 14 , wherein the second alloy comprises 1-10 wt. % cerium, 3-30 wt. % silver and 60 to 96 wt. % tin.  
     
     
         16 . The method of  claim 14 , further comprising adding a third alloy to the molten first alloy, wherein the second alloy comprises 1-10 wt. % cerium and the balance tin; and the third alloy comprises 3-30 wt. % silver and the balance tin.  
     
     
         17 . The method of  claim 11 , further comprising: 
 adding a scavenger to the molten first alloy to form a scavenger-contaminant complex; and    removing the scavenger-contaminant complex from the molten first alloy prior to addition of the second alloy.    
     
     
         18 . The method of  claim 11 , wherein the shape of the solid form of the lead-free alloy is selected from the group consisting of a wire, bar, paste, foil, preform and powder.  
     
     
         19 . The method of  claim 18 , further comprising the step of combining the powder with a flux to form a solder paste.  
     
     
         20 . A method of using a lead-free solder alloy for joining metal surfaces in plumbing, refrigeration, and roofing applications, wherein the alloy comprises tin, antimony, copper, silver, and a lanthanide metal; and the alloy is substantially free of group IVa elements, group Va elements, bismuth, nickel, and zinc.  
     
     
         21 . The method of  claim 20 , wherein the lanthanide metal is selected from the group consisting of lanthanum, cerium, neodynium, samarium, europium and mixtures thereof.  
     
     
         22 . The method alloy of  claim 21 , wherein the lead-free alloy comprises at least 96 wt. % tin, 0.25 to 1 wt. % antimony, 1 to 4 wt. % copper, 0.05 to 0.5 wt. % silver and 0.1 to 0.3 wt. % lanthanide metal.  
     
     
         23 . The method of  claim 22 , wherein the lanthanide content is 0.03% to 0.1 wt. % based on the weight of the alloy.  
     
     
         24 . The lead-free alloy of  claim 21 , wherein the lanthanide metal is cerium.  
     
     
         25 . The method of  claim 24 , wherein the lead-free alloy comprises at least 96 wt. % tin, 0.25 to 1% wt. % antimony, 1 to 4 wt. % copper, 0.05 to 0.5 wt. % silver, and 0.01 to 0.3 wt. % cerium.  
     
     
         26 . The method of  claim 25 , wherein the cerium content is 0.03% to 0.1 wt. % based on the weight of the alloy.  
     
     
         27 . The method of  claim 20 , wherein the metal surface is selected from the group consisting of brass, bronze, copper, steel, stainless steel, monel and galvanized metal.  
     
     
         28 . A lead-free babbitt alloy wherein the alloy comprises tin, antimony, copper, silver, and a lanthanide metal; and the alloy is substantially free of group IVa elements, group Va elements, bismuth, nickel, and zinc.  
     
     
         29 . The lead-free babbitt alloy of  claim 28 , wherein the lanthanide metal is selected from the group consisting of lanthanum, cerium, neodynium, samarium, europium and mixtures thereof.  
     
     
         30 . The lead-free babbitt alloy of  claim 29 , wherein the alloy comprises at least 84 wt. % tin, 3 to 8 wt. % antimony, 3 to 8 wt. % copper, 0.05 to 0.5 wt. % silver, and 0.01 to 0.3 wt. % lanthanide metal.  
     
     
         31 . The lead-free babbitt alloy of  claim 30 , wherein the lanthanide metal content is 0.03 to 0.1 wt. % based on the total weight of the alloy.  
     
     
         32 . The lead-free babbitt alloy of  claim 29 , wherein the lanthanide metal is cerium.  
     
     
         33 . The lead-free babbitt alloy of  claim 32 , wherein the alloy comprises at least 84 wt. % tin, 3 to 8 wt. % antimony, 3 to 8 wt. % copper, 0.05 to 0.5 wt. % silver, and 0.01 to 0.3 wt. % cerium.  
     
     
         34 . The lead-free babbitt alloy of  claim 33 , wherein the cerium-content is 0.03 to 0.1 wt. % based on the total weight of the alloy.  
     
     
         35 . The lead-free babbitt alloy of  claim 33 , wherein the melting range is from about 275° C. to about 375° C.  
     
     
         36 . The lead-free babbitt alloy of  claim 35 , wherein the melting range is from about 300° C. to about 350° C.  
     
     
         37 . A method of preparing a lead free-babbitt alloy comprising: 
 preparing a molten first alloy comprising tin, antimony and copper;    adding a lanthanide-containing second alloy to the molten first alloy to form a molten lead-free alloy;    forming the molten lead-free alloy into a shape; and    cooling the lead-free alloy to form a solid form of said shape; wherein    the lead-free alloy is substantially free of group IVa elements, group Va elements, bismuth, nickel and zinc.    
     
     
         38 . The method of  claim 37 , wherein the lanthanide metal is selected from the group consisting of lanthanum, cerium, neodynium, samarium, europium and mixtures thereof.  
     
     
         39 . The method of  claim 38 , wherein the lead-free alloy comprises at least 84 wt. % tin, 3 to 8 wt. % antimony, 3 to 8 wt. % copper, 0.05 to 0.5 wt. % silver, and 0.01 to 0.30 wt. % lanthanide metal.  
     
     
         40 . The method of  claim 39 , wherein the lanthanide metal content is 0.03 to 0.1 wt. % based on the total weight of the alloy.  
     
     
         41 . The method of  claim 38 , wherein the lanthanide metal is cerium.  
     
     
         42 . The method of  claim 41 , wherein the lead-free alloy comprises at least 84 wt. % tin, 3 to 8 wt. % antimony, 3 to 8 wt. % copper, 0.05 to 0.5 wt. % silver, and 0.01 to 0.3 wt. % cerium.  
     
     
         43 . The method of  claim 42 , wherein the cerium content is 0.03 to 0.1 wt. % based on the total weight of the alloy.  
     
     
         44 . The method of  claim 41 , wherein the molten first alloy is prepared from 3 to 8 parts by weight copper, 3 to 8 parts by weight antimony, and 85 to 94 parts weight tin.  
     
     
         45 . The method of  claim 44 , wherein the second alloy comprises 1-10 wt. % cerium, 3-30 wt. % silver and 60 to 96 wt. % tin.  
     
     
         46 . The method of  claim 44 , further comprising adding a third alloy to the molten first alloy, wherein the second alloy comprises 1-10 wt. % cerium and the balance tin; and the third alloy comprises 3-30 wt. % silver and the balance tin.  
     
     
         47 . The method of  claim 37 , further comprising: 
 adding a scavenger to the molten first alloy to form a scavenger-contaminant complex; and    removing the scavenger-contaminant complex from the molten first alloy prior to addition of the second alloy.    
     
     
         48 . A method of using a lead-free alloy for babbiting wherein the alloy comprises tin, antimony, copper, silver, and a lanthanide metal; and the alloy is substantially free of group IVa elements, group Va elements, bismuth, nickel, and zinc.  
     
     
         49 . The method of  claim 48 , wherein the lanthanide metal is selected from the group consisting of lanthanum, cerium, neodynium, samarium, europium and mixtures thereof.  
     
     
         50 . The method of  claim 49 , wherein lead-free alloy comprises at least 84 wt. % tin, 3 to 8 wt. % antimony, 3 to 8 wt. % copper, 0.05 to 0.5 wt. % silver, and 0.01 to 0.3 wt. % lanthanide metal.  
     
     
         51 . The method of  claim 50 , wherein the lanthanide metal content is 0.03 to 0.10 wt. % based on the total weight of the babbitt alloy.  
     
     
         52 . The method of  claim 49 , wherein the lanthanide metal is cerium.  
     
     
         53 . The method of  claim 52 , wherein lead-free alloy comprises at least 84 wt. % tin, 3 to 8 wt. % antimony, 3 to 8 wt. % copper, 0.05 to 0.5 wt. % silver, and 0.01 to 0.3 wt. % cerium.  
     
     
         54 . The method of  claim 53 , wherein the cerium content is 0.03 to 0.10 wt. % based on the total weight of the babbitt alloy.