Method for manufacturing spherical metal powder

Abstract

An embodiment of the present invention provides a method for manufacturing spherical metal powder, comprising the steps of: (a) forming a slurry by mixing ultra-fine raw metal with a binder and a solvent; (b) forming granular powders by granulating the slurry through spray drying; (c) adding a separating agent to prevent sintering between the granular powders; (d) forming spherical metal powder by continuously degreasing and sintering the granular powders; (e) adding a deoxidizer for high purity of the sintered spherical metal powder to carry out deoxidation treatment; and (f) removing the separating agent and an oxide from the deoxidized spherical metal powder.

1 . A method of preparing spherical metal powder, comprising:
 (a) mixing an ultra-fine raw metal with a binder and a solvent to form a slurry;   (b) granulating the slurry through spray drying to form granular powder;   (c) adding a separating agent to prevent sintering between granular powder particles;   (d) continuously performing degreasing and sintering on the granular powder to form spherical metal powder;   (e) performing deoxidation treatment by adding a deoxidizer to achieve high purity of the sintered spherical metal powder; and   (f) removing the separating agent and oxide from the deoxidized spherical metal powder.   
     
     
         2 . The method of  claim 1 , wherein the spherical metal powder is selected from the group consisting of CP—Ti-based alloys, Ti—Al-based alloys, Ti—Al—V-based alloys, and a combination thereof. 
     
     
         3 . The method of  claim 1 , wherein a particle size range of the spherical metal powder is 1 to 300 μm. 
     
     
         4 . The method of  claim 1 , wherein the ultra-fine raw metal is one or more selected from the group consisting of titanium hydride, titanium, aluminum, vanadium, tin, palladium, nickel, molybdenum, chromium, cobalt, zirconium, zirconium hydride, niobium, and a combination thereof. 
     
     
         5 . The method of  claim 1 , wherein the ultra-fine raw metal is prepared from a raw material selected from the group consisting of titanium sponge, titanium scrap, and a combination thereof. 
     
     
         6 . The method of  claim 1 , wherein in step (a), the solvent includes water and ethyl alcohol, the binder includes a polyvinyl pyrrolidone (PVP) binder, which are physically mixed using a mixing device. 
     
     
         7 . The method of  claim 6 , wherein in step (a), 100 to 500 ml of ethyl alcohol, 50 to 650 g of an ultra-fine raw metal, and 16 to 150 ml of PVP are mixed with respect to 1 L of water. 
     
     
         8 . The method of  claim 1 , wherein in step (b), the spray drying is performed by intermittently spraying the slurry at a pneumatic pressure of 2 to 8 kg/cm 2  in a chamber maintained at a vacuum of 10 −1  torr or less to form granular powder. 
     
     
         9 . The method of  claim 1 , wherein a particle size range of the granular powder is 1 to 350 μm. 
     
     
         10 . The method of  claim 9 , wherein in step (b), the granular powder that is outside the particle size range after granulation is re-granulated. 
     
     
         11 . The method of  claim 1 , wherein in step (c), the separating agent includes MgO powder, K 2 O powder, or a mixture thereof. 
     
     
         12 . The method of  claim 1 , wherein in step (d), a degreasing initial vacuum degree is 10 −6  to 10 −2  torr. 
     
     
         13 . The method of  claim 1 , wherein in step (d), a degreasing temperature is 100 to 500° C., and a temperature increase rate consists of two stages of 2 to 8° C./min and 9 to 20° C./min. 
     
     
         14 . The method of  claim 1 , wherein in step (d), a sintering temperature is 600° C. to 1500° C. 
     
     
         15 . The method of  claim 14 , wherein in step (d), a sintering temperature increase rate consists of two stages of 2 to 8° C./min and 9 to 20° C./min, and a sintering holding time is 1 min to 50 h. 
     
     
         16 . The method of  claim 1 , wherein in step (d), sintering is performed until pores inside the granular powder is controlled to 10% or less. 
     
     
         17 . The method of  claim 1 , wherein in step (d), sintering is performed until pores inside the granular powder is controlled to 5% or less. 
     
     
         18 . The method of  claim 1 , wherein in step (e), the deoxidizer is Ca gas, Mg gas, or a combination thereof. 
     
     
         19 . The method of  claim 1 , wherein in step (e), a deoxidation initial vacuum degree is 10 −6  to 10 −2  torr. 
     
     
         20 . The method of  claim 1 , wherein in step (e), a deoxidation temperature is 800 to 1100° C. 
     
     
         21 . The method of  claim 20 , wherein a deoxidation temperature increase rate is 5 to 10° C./min, and a deoxidation holding time after the temperature increase is 1 to 5 h. 
     
     
         22 . The method of  claim 1 , wherein in step (f), the deoxidized spherical metal powder is pickled and washed with water in dilute hydrochloric acid, dilute sulfuric acid, or a mixture thereof to remove remaining oxides. 
     
     
         23 . The method of  claim 1 , wherein in step (f), the spherical metal powder from which the separating agent and oxide have been removed is dried at 50 to 150° C. 
     
     
         24 . The method of  claim 23 , wherein in step (f), a drying time is 1 min to 5 h.