Powder metal with solid lubricant and powder metal scroll compressor made therefrom

Abstract

A powder metal formulation includes a solid lubricant and is particularly useful for the production of powder metal scroll compressors.

What is claimed is: 
     
         1 . A powder metal scroll compressor comprising:
 a hub and a scroll adjoined to one another;   a powder metal forming at least a portion of the powder metal scroll compressor including the scroll, the powder metal including iron powder, carbon in an amount of less than 0.9% by weight of the powder metal, and a solid lubricant in the powder metal.   
     
     
         2 . The powder metal scroll compressor of  claim 1 , wherein the iron powder and solid lubricant are admixed with one another prior to compaction and sintering of the powder metal scroll compressor. 
     
     
         3 . The powder metal scroll compressor of  claim 1 , wherein the solid lubricant is 0.25% to 3.0% by weight of the powder metal and the powder metal includes iron powder, carbon, the solid lubricant and is substantially free of other constituents. 
     
     
         4 . The powder metal scroll compressor of  claim 1 , wherein the powder metal further includes copper powder in an amount of less than 3.0% by weight of the powder metal. 
     
     
         5 . The powder metal scroll compressor of  claim 4 , wherein the iron powder, the copper powder, and the solid lubricant are admixed with one another prior to compaction and sintering of the powder metal scroll compressor and the powder metal includes iron powder, carbon, copper powder, and the solid lubricant and is substantially free of other constituents. 
     
     
         6 . The powder metal scroll compressor of  claim 4 , wherein the copper powder is elemental copper powder. 
     
     
         7 . The powder metal scroll compressor of  claim 1 , wherein the solid lubricant is talc (Mg 3 Si 4 O 10 (OH) 2 ). 
     
     
         8 . The powder metal scroll compressor of  claim 7 , wherein the talc has a nominal 15 to 25 micron mean particle size (d50). 
     
     
         9 . The powder metal scroll compressor of  claim 1 , wherein the solid lubricant is hexagonal boron nitride (BN). 
     
     
         10 . The powder metal scroll compressor of  claim 9 , wherein the hexagonal boron nitride has a nominal 5 to 30 micron mean particle size (d50). 
     
     
         11 . The powder metal scroll compressor of  claim 1 , wherein the solid lubricant remains inert and stable in an Fe—C or an Fe—Cu—C system through processing of temperatures up to 1080 degrees Centigrade. 
     
     
         12 . The powder metal scroll compressor of  claim 1 , wherein the solid lubricant is a nickel-coated graphite powder and in which the carbon in an amount of less than 0.9% by weight of the powder metal material is exclusive of the graphite of the nickel-coated graphite powder. 
     
     
         13 . The powder metal scroll compressor of  claim 12 , wherein a nickel coating of the nickel-coated graphite powder substantially surrounds the graphite to protect the graphite during sintering of the powder metal scroll compressor and to prevent the graphite from combining with the iron powder. 
     
     
         14 . The powder metal scroll compressor of  claim 12 , wherein a nickel content of the nickel-coated graphite powder is in a range of 55 to 80 wt % with the remainder being graphite. 
     
     
         15 . The powder metal scroll compressor of  claim 12 , wherein a total amount of graphite in the powder metal scroll compressor is in the range of 0.5 to 5.0 wt % exclusive of the carbon in an amount of less than 0.9% by weight of the powder metal material. 
     
     
         16 . The powder metal scroll compressor of  claim 12 , wherein a total amount of graphite in the powder metal scroll compressor is in the range of 1.0 to 3.0 wt % exclusive of the carbon in an amount of less than 0.9% by weight of the powder metal material. 
     
     
         17 . The powder metal scroll compressor of  claim 12 , wherein the nickel-coated graphite powder has an average particle size of approximately 100 microns. 
     
     
         18 . A powder metal comprising:
 iron powder;   carbon in an amount of less than 0.9% by weight of the powder metal material; and   a solid lubricant;   in which the iron powder and solid lubricant are admixed with one another.   
     
     
         19 . The powder metal of  claim 18 , wherein the solid lubricant is 0.25% to 3.0% by weight of the powder metal. 
     
     
         20 . The powder metal of  claim 18 , wherein the powder metal further includes copper powder in an amount of less than 3.0% by weight of the powder metal. 
     
     
         21 . The powder metal of  claim 20 , wherein the iron powder, the copper powder, and the solid lubricant are admixed with one another and the powder metal includes iron powder, carbon, copper powder, and the solid lubricant and is substantially free of other constituents. 
     
     
         22 . The powder metal of  claim 20 , wherein the copper powder is elemental copper powder. 
     
     
         23 . The powder metal of  claim 20 , wherein the solid lubricant is talc (Mg 3 Si 4 O 10 (OH) 2 ). 
     
     
         24 . The powder metal of  claim 23 , wherein the talc has a nominal 15 to 25 micron mean particle size (d50). 
     
     
         25 . The powder metal of  claim 18 , wherein the solid lubricant is hexagonal boron nitride (BN). 
     
     
         26 . The powder metal of  claim 25 , wherein the hexagonal boron nitride has a nominal 5 to 30 micron mean particle size (d50). 
     
     
         27 . The powder metal of  claim 18 , wherein the solid lubricant remains inert and stable in an Fe—C or an Fe—Cu—C system through processing of temperatures up to 1080 degrees Centigrade. 
     
     
         28 . The powder metal of  claim 18 , wherein the powder metal includes iron powder, carbon, the solid lubricant and is substantially free of other constituents. 
     
     
         29 . The powder metal of  claim 18 , wherein the solid lubricant is a nickel-coated graphite powder and in which the carbon in an amount of less than 0.9% by weight of the powder metal material is exclusive of the graphite of the nickel-coated graphite powder. 
     
     
         30 . The powder metal of  claim 29 , wherein a nickel coating of the nickel-coated graphite powder substantially surrounds the graphite to protect the graphite during sintering of the powder metal scroll compressor and to prevent the graphite from combining with the iron powder. 
     
     
         31 . The powder metal of  claim 29 , wherein a nickel content of the nickel-coated graphite powder is in a range of 55 to 80 wt % with the remainder being graphite. 
     
     
         32 . The powder metal of  claim 29 , wherein a total amount of graphite in the powder metal scroll compressor is in the range of 0.5 to 5.0 wt % exclusive of the carbon in an amount of less than 0.9% by weight of the powder metal material. 
     
     
         33 . The powder metal of  claim 29 , wherein a total amount of graphite in the powder metal scroll compressor is in the range of 1.0 to 3.0 wt % exclusive of the carbon in an amount of less than 0.9% by weight of the powder metal material. 
     
     
         34 . The powder metal of  claim 29 , wherein the nickel-coated graphite powder has an average particle size of approximately 100 microns. 
     
     
         35 . A part made using the powder metal of  claim 18 , wherein the powder metal is compacted and sintered to form the part and the solid lubricant is retained throughout the process and is dispersed throughout the part including the surface of the part.