Methods for preparing metallurgical powder compositions and compacted articles made from the same

Abstract

Provided are methods of preparing high density compacted components that increase that lubricity of metallurgical powder compositions while reducing the overall organic content of the compacted component. Method of preparing high density compacted components having a high density include the steps of providing a metallurgical powder composition having particles at least partially coated with a metal phosphate layer, and compacting the metallurgical powder composition in the die at a pressure of at least about 5 tsi. The metallurgical powder composition comprises a base-metal powder, optional alloying powders, and a particulate internal lubricant. The metal phosphate at least partially coats the base-metal powder, the optional alloying powder, or both. The metal phosphate coating increases the lubricity of metallurgical powders without the need for large quantities of organic material, e.g., lubricants and binders.

1 . A metallurgical powder composition comprising: 
 (a) at least 85 weight percent of a base-metal powder;    (b) from about 0.01 to about 1.0 weight percent, based on the weight of the base-metal powder, of metal phosphate that at least partially coats the base-metal powder.    
   
   
       2 . The metallurgical powder composition of  claim 1 , further comprising a particulate internal lubricant.  
   
   
       3 . The metallurgical powder composition of  claim 2 , wherein the particulate internal lubricant is a polyamide, a C 5  to C 30  fatty acid, a metal salt of a polyamide, a metal salt of a C 5  to C 30  fatty acid, an ammonium salt of a C 5  to C 30  fatty acid, lithium stearate, zinc stearate, manganese stearate, calcium stearate, ethylene bis-stearamide, polyethylene wax, polyolefin, or combinations thereof.  
   
   
       4 . The metallurgical powder composition of  claim 2 , wherein the particulate internal lubricant comprises: 
 (i) a polyamide lubricant, and    (ii) a stearate lubricant.    
   
   
       5 . The metallurgical powder composition of  claim 2 , wherein the particulate internal lubricant comprises: 
 about 0.2 weight percent of a polyamide lubricant composed of ethylene bis-stearamide having an initial melting point between about 200° C. and 300° C., and about 0.2 weight percent of Kenolube™.    
   
   
       6 . The metallurgical powder composition of  claim 1 , further comprising: 
 about 0.10 weight percent binding agent, wherein the particulate internal lubricant comprises:    about 0.15 weight percent of a polyamide lubricant composed of ethylene bis-stearamide having an initial melting point between about 200° C. and 300° C., and about 0.15 weight percent of Kenolube™.    
   
   
       7 . The metallurgical powder composition of  claim 2 , wherein the particulate internal lubricant is present in an amount from about 0.01 to about 2.0 weight percent by weight of base-metal powder.  
   
   
       8 . The metallurgical powder composition of  claim 1 , wherein said metal phosphate is manganese zinc phosphate, nickel phosphate, zinc phosphate, copper phosphate, or combinations thereof.  
   
   
       9 . The metallurgical powder composition of  claim 1 , wherein the metal phosphate is present in an amount from about 0.05 to about 0.40 weight percent by weight of base-metal powder.  
   
   
       10 . The metallurgical powder composition of  claim 1 , wherein the base-metal powder is an iron based powder.  
   
   
       11 . The metallurgical powder composition of  claim 10 , wherein the iron based powder comprises an alloying powder.  
   
   
       12 . The metallurgical powder composition of  claim 10 , wherein the iron based powder is a prealloyed iron base powder.  
   
   
       13 . The metallurgical powder composition of  claim 10 , wherein the iron based powder is a diffusion bonded iron based powder.  
   
   
       14 . The metallurgical powder composition of  claim 1 , wherein the iron based powder is a ferromagnetic powder.  
   
   
       15 . A compacted article comprising a compacted metallurgical powder composition comprising: 
 (i) at least 85 weight percent of a base-metal powder;    (ii) from about 0.01 to about 1.0 weight percent, based on the weight of the base-metal powder, of metal phosphate that at least partially coats the base-metal powder.    
   
   
       16 . The compacted article of  claim 15 , wherein the compacted article is sintered.  
   
   
       17 . The compacted article of  claim 15 , wherein the metal phosphate is manganese zinc phosphate, nickel phosphate, copper phosphate, or zinc phosphate.  
   
   
       18 . A method of preparing a metallurgical powder composition comprising: 
 (a) providing a base-metal powder,    (b) providing a coating solution of metal phosphate and protonic acid, and    (c) contacting the iron based particles with the coating solution so as to at least partially coat said iron particles with the metal phosphate.    
   
   
       19 . The method of preparing a metallurgical powder composition of  claim 18 , further comprising a step of providing a particulate internal lubricant.  
   
   
       20 . The method of preparing a metallurgical powder composition of  claim 19 , wherein the metallurgical powder composition comprises from about 0.01 to about 2.0 weight percent by weight of a particulate internal lubricant.  
   
   
       21 . The method of preparing a metallurgical powder composition of  claim 18  further comprising the step of admixing a particulate internal lubricant with the base metal powder prior to being coated with the metal phosphate, the particulate internal lubricant thereby also being contacted with the coating solution.  
   
   
       22 . The method of preparing a metallurgical powder composition of  claim 18  further comprising the step of admixing a particulate internal lubricant with the base metal powder after the base metal powder is coated with the metal phosphate.  
   
   
       23 . The method of preparing a metallurgical powder composition of  claim 19  wherein the base-metal powder is bonded with about 0.10 weight percent binding agent, and the particulate internal lubricant comprises: 
 about 0.15 weight percent of a polyamide lubricant composed of ethylene bis-stearamide having an initial melting point between about 200° C. and 300° C., and    about 0.15 weight percent of Kenolube™.    
   
   
       24 . The method of preparing a metallurgical powder composition of  claim 19 , wherein the particulate internal lubricant comprises: 
 about 0.2 weight percent of a polyamide lubricant composed of ethylene bis-stearamide having an initial melting point between about 200° C. and 300° C., and    about 0.2 weight percent of Kenolube™.    
   
   
       25 . The method of preparing a metallurgical powder composition of  claim 18 , further comprising a step of admixing an alloying powder with the base metal powder after the base metal powder is coated with the metal phosphate.  
   
   
       26 . The method of preparing a metallurgical powder composition of  claim 25 , wherein the alloying powder comprises graphite, Ni, Cu, FeP, ferroalloy, or combinations thereof.  
   
   
       27 . The method of preparing a metallurgical powder composition of  claim 18 , wherein the metallurgical powder composition comprises from about 0.05 to about 1.0 weight percent of metal phosphate.  
   
   
       28 . The method of preparing a metallurgical powder composition of  claim 18 , wherein the base-metal powder is an iron based powder.  
   
   
       29 . The method of preparing a metallurgical powder composition of  claim 28 , wherein the iron based powder comprises an alloying powder.  
   
   
       30 . The method of preparing a metallurgical powder composition of  claim 28 , wherein the iron based powder is a prealloyed iron base powder.  
   
   
       31 . The method of preparing a metallurgical powder composition of  claim 28 , wherein the iron based powder is a diffusion bonded iron based powder.  
   
   
       32 . The method of preparing a metallurgical powder composition of  claim 28 , wherein the iron based powder is a ferromagnetic powder.  
   
   
       33 . Methods of preparing compacted articles comprising the steps of: 
 (a) providing a metallurgical powder composition comprising: 
 (i) at least 85 weight percent of a base-metal powder; and  
 (ii) from about 0.01 to about 1.0 weight percent, based on the weight of the base-metal powder, of metal phosphate that at least partially coats the base-metal powder;  
   (b) compacting the metallurgical powder composition in a die at a pressure of at least about 5 tsi.    
   
   
       34 . The methods of preparing compacted articles of  claim 33 , further comprising the step of sintering the compact part.  
   
   
       35 . The methods of preparing compacted articles of  claim 33 , wherein said metal phosphate is manganese zinc phosphate, nickel phosphate, zinc phosphate, copper phosphate, or combinations thereof.  
   
   
       36 . The methods of preparing compacted articles of  claim 33 , wherein the metal phosphate is present in an amount from about 0.05 to about 0.40 weight percent by weight of base-metal powder.  
   
   
       37 . The methods of preparing compacted articles of  claim 33 , wherein the metallurgical powder composition further comprises a particulate internal lubricant.  
   
   
       38 . The methods of preparing compacted articles of  claim 37 , wherein the particulate internal lubricant is present in an amount from about 0.01 to about 2.0 weight percent by weight of base-metal powder.  
   
   
       39 . The methods of preparing compacted articles of  claim 37 , wherein the particulate internal lubricant is a polyamide, a C 5  to C 30  fatty acid, a metal salt of a polyamide, a metal salt of a C 5  to C 30  fatty acid, an ammonium salt of a C 5  to C 30  fatty acid, lithium stearate, zinc stearate, manganese stearate, calcium stearate, ethylene bis-stearamide, polyethylene wax, polyolefin or combinations thereof.  
   
   
       40 . The methods of preparing compacted articles of  claim 33 , wherein the base-metal powder is an iron based powder.  
   
   
       41 . The methods of preparing compacted articles of  claim 33 , wherein the iron based powder comprises an alloying powder.  
   
   
       42 . The methods of preparing compacted articles of  claim 40 , wherein the iron based powder is a prealloyed iron base powder.  
   
   
       43 . The methods of preparing compacted articles of  claim 40 , wherein the iron based powder is a diffusion bonded iron based powder.  
   
   
       44 . The methods of preparing compacted articles of  claim 40 , wherein the iron based powder is a ferromagnetic powder.  
   
   
       45 . The methods of preparing compacted articles of  claim 33 , wherein the base-metal powder is coated by the steps comprising: 
 (a) providing a base-metal powder,    (b) providing a coating solution of metal phosphate and protonic acid,    (c) contacting the iron based particles with the coating solution to at least partially coat said iron particles with the metal phosphate.    
   
   
       46 . The methods of preparing compacted articles of  claim 45 , wherein the protonic acid is diluted in acetone.  
   
   
       47 . The methods of preparing compacted articles of  claim 45 , wherein the protonic acid is sulphuric acid, nitric acid, hydrochloric acid, phosphoric acid, or combinations thereof.  
   
   
       48 . The methods of preparing compacted articles of  claim 33 , further comprising the step of sintering the compacted metallurgical powder composition.