HOMOGENEOUS GRANULATED METAL BASED and METAL-CERAMIC BASED POWDERS

Abstract

A method of making a homogeneous granulated metal-based powder, comprises steps of: providing preselected amounts of at least one metal element or metal alloy, at least one ceramic compound, and/or at least one non-metallic element; forming a homogeneous slurry/suspension or wet mixture comprising the preselected amounts of metal element(s) and/or metal alloys, ceramic compound(s), and/or non-metallic element(s), a liquid phase comprising at least one liquid, and at least one binder material; drying the slurry/suspension or mixture to remove at least a portion of the liquid phase and form a powder mixture comprising partially or completely dried granules; and subjecting the granules to a thermal de-binder process for effecting: additional removal of any remaining liquid phase, if necessary; removal of the at least one binder material; reduction of carbon content; reduction of oxygen on the surfaces or interior of the metal or metal alloy phases in the granules; and optional partial sintering for strengthening for withstanding subsequent processing. The resultant granules are useful in fabricating magnetic sputtering targets employed in the manufacture of magnetic data/information storage and retrieval media.

1 . A method of making a homogeneous granulated metal-based powder, comprising steps of:
 (a) providing a preselected amount of at least one metal element or metal alloy and a preselected amount of at least one ceramic compound and/or at least one non-metallic element;   (b) forming a homogeneous slurry/suspension or wet mixture comprising said preselected amounts of said at least one metal element or metal alloy and said at least one ceramic compound and/or said at least one non-metallic element, and a liquid phase comprising at least one liquid, at least one binder material, and at least one optional additive;   (c) drying said slurry/suspension or said mixture to remove at least a portion of said liquid phase and form a powder mixture comprising partially or completely dried granules; and   (d) subjecting said partially or completely dried granules to a thermal de-binder process for effecting:
 (i) additional removal of any liquid phase, if required; 
 (ii) removal of said at least one binder material; 
 (iii) reduction of carbon content; 
 (iv) reduction of oxygen on the surfaces or interior of the metal constituent(s); and optional 
 (v) partial sintering for strengthening the particles for withstanding subsequent processing. 
   
     
     
         2 . The method according to  claim 1 , wherein:
 step (a) comprises providing a preselected amount of a powder containing said at least one metal element or metal alloy, a preselected amount of another powder containing said at least one ceramic compound, and/or a preselected amount of another powder containing the at least one non-metallic element.   
     
     
         3 . The method according to  claim 2 , wherein:
 step (a) comprises providing preselected amounts of a plurality of powders containing respective metal elements and/or metal alloys, respective ceramic compounds, and/or respective non-metallic elements.   
     
     
         4 . The method according to  claim 3 , wherein:
 step (a) comprises providing preselected amounts of two powders respectively containing first and second metal elements and/or alloys and/or preselected amounts of two powders respectively containing first and second ceramic compounds and/or non-metallic elements.   
     
     
         5 . The method according to  claim 1 , wherein:
 step (a) comprises providing a preselected amount of a compound of said at least one metal or metal alloy and a preselected amount of a sol-gel of said at least one ceramic compound or said at least one non-metallic element.   
     
     
         6 . The method according to  claim 1 , wherein:
 step (a) comprises providing a preselected amount of at least one metal element or metal alloy comprising metals selected from the group consisting of: Co, Cr, Fe, Pt, Pd, Ru, Re, Ta, Al, Sm, and Nd, a preselected amount of at least one non-metallic compound selected from the group consisting of: TiO 2 , SiO 2 , MgO, Ta 2 O 5 , Nb 2 O 5 , A 1   2 O 3 , TaC, BN, ZrO 2 , HfO 2 , ZnO, CaO, La 2 O 3 , WO 3 , CoO, Co 2 O 3 , Y 2 O 3 , Cr 2 O 3 , MnO 2 , NiO, CuO, CeO 2 , Eu 2 O 3 , V 2 O 5 , Sm 2 O 3 , Sb 2 O 5 , BeO, BaO, B 2 O 3 , IrO 2 , PbO, MoO 3 , ReO 2 , RuO 2 , Ag 2 O, SrO, TaC, NbC, BN, B, and C.   
     
     
         7 . The method according to  claim 6 , wherein:
 step (a) comprises providing preselected amounts of a plurality of metal elements and/or metal alloys, ceramic compounds, and/or non-metallic elements selected from said groups.   
     
     
         8 . The method according to  claim 1 , wherein:
 step (b) comprises forming said homogeneous slurry/suspension or wet mixture to comprise a liquid phase comprising at least one of water, an alcohol, and at least one organic solvent, and further comprising at least one inorganic or organic binder material.   
     
     
         9 . The method according to  claim 8 , wherein:
 step (b) comprises forming said homogeneous slurry/suspension or wet mixture to comprise a liquid phase comprising at least one of water, an alcohol, and at least one organic solvent selected from the group consisting of: acetone, toluene, hexane, heptane, xylene, and decane.   
     
     
         10 . The method according to  claim 8 , wherein:
 step (b) comprises forming said homogeneous slurry/suspension or wet mixture to further comprise at least one organic binder material selected from the group consisting of: polyvinyl alcohol (PVA), polyethylene glycol (PEG), gum arabic, other natural gums, methyl cellulose, acrylic resin emulsions, ethylene oxide polymers, water soluble phenolics, alginates, natural or synthetic waxes, flour, starches, or at least one inorganic binder material selected from the group consisting of: carbonates, nitrides, oxylates, and oxychlorides.   
     
     
         11 . The method according to  claim 8 , wherein:
 step (b) comprises forming said homogeneous slurry/suspension or wet mixture to further comprise at least one of a deflocculating agent, wetting agent, de-foaming agent, plasticizer, and suspending agent.   
     
     
         12 . The method according to  claim 1 , wherein:
 step (c) comprises spray drying.   
     
     
         13 . The method according to  claim 1 , wherein:
 step (d) comprises performing said thermal de-binder process to reduce said carbon content of said granules to less than about 500 ppm.   
     
     
         14 . The method according to  claim 13 , wherein:
 step (d) comprises performing said thermal de-binder process in an atmosphere comprising at least one reducing gas.   
     
     
         15 . The method according to  claim 14 , wherein:
 step (d) comprises performing said thermal de-binder process in an atmosphere comprising at least one reducing gas selected from the group consisting of: H 2 , NH 3 , CO, forming gas, dissociated NH 3 , H 2 /N 2  mixtures, and reformed hydrocarbon gases.   
     
     
         16 . The method according to  claim 14 , wherein:
 step (d) comprises performing said thermal de-binder process in an atmosphere further comprising at least one weak oxidizing agent.   
     
     
         17 . The method according to  claim 16 , wherein:
 step (d) comprises performing said thermal de-binder process in an atmosphere comprising at least one weak oxidizing agent selected from the group consisting of: H 2 O, CO 2 , air, O 2 , and air or O 2  diluted in an inert gas or a weakly oxidizing or non-oxidizing gas.   
     
     
         18 . The method according to  claim 14 , wherein:
 step (d) comprises performing said thermal de-binder process in an atmosphere comprising said at least one reducing gas only in a latter portion of said thermal de-binder process, and at a same or different temperature than in an earlier portion of said process.   
     
     
         19 . A homogeneous granulated metal based or metal-ceramic based powder formed by the method according to  claim 1 . 
     
     
         20 . A homogeneous granulated metal-based powder as in  claim 19 , comprising at least one metal element or metal alloy comprising elements selected from the group consisting of: Co, Cr, Fe, Pt, Pd, Ru, Re, Ta, Al, and Sm, and at least one ceramic compound or non-metallic element selected from the group consisting of: TiO 2 , SiO 2 , MgO, Ta 2 O 5 , Nb 2 O 5 , Al 2 O 3 , TaC, BN, ZrO 2 , HfO 2 , ZnO, CaO, La 2 O 3 , WO 3 , CoO, Co 2 O 3 , Y 2 O 3 , Cr 2 O 3 , MnO 2 , NiO, CuO, CeO 2 , Eu 2 O 3 , V 2 O 5 , Sm 2 O 3 , Sb 2 O 5 , BeO, BaO, B 2 O 3 , IrO 2 , PbO, MoO 3 , ReO 2 , RuO 2 , Ag 2 O, SrO, TaC, NbC, BN, B, and C. 
     
     
         21 . A magnetic sputtering target fabricated from a homogeneous granulated metal-based magnetic powder of  claim 20 . 
     
     
         22 . The method according to  claim 1 , wherein:
 step (a) comprises providing only a fraction of the requisite metal or metal alloy powders and a fraction or all of the requisite ceramic, oxide, and/or non-metallic element powders; and the method further comprises a step of:   (e) blending the resultant granulated powder with the balance of requisite metal or metal alloy powders and ceramic, oxide, and/or non-metallic element powders for consolidation therewith.