Porous silver powders and method for preparing the same

Abstract

Provided is a porous silver powder and a preparation method thereof. More specifically, the present invention relates to porous silver powder that is easy to prepare, improves a sterilization effect because an specific surface area and a porosity are easily adjustable, improves electrical conductivity when molded as sintered body, contributes to reducing use of expensive silver when applied in various industrial fields, thus achieving price competitiveness, and is harmless to the human body because a particle size is adjustable to prevent the porous silver powder from being absorbed into the body; and a preparation method thereof.

What is claimed is: 
     
         1 . Porous silver powder, wherein pores are formed by etching alloy powder containing silver (Ag) and an alloying element other than silver (Ag) with an acid solution or a basic solution to remove at least part of the alloying element. 
     
     
         2 . The porous silver powder of  claim 1 , wherein residual content of the alloying element is 0.5 to 3% by weight based on the total weight of the porous silver powder. 
     
     
         3 . The porous silver powder of  claim 1 , wherein the alloying element comprises at least one material selected from the group consisting of silicon (Si), bismuth (Bi), germanium (Ge), copper (Cu), iron (Fe), nickel (Ni), chromium (CR), and cobalt (Co). 
     
     
         4 . The porous silver powder of  claim 3 , wherein the alloying element further comprises at least one transition metal element. 
     
     
         5 . The porous silver powder of  claim 1 , wherein the basic solution comprises at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, an ammonia solution, zinc chloride, tetramethyl ammonium hydroxide (TMAH), and ethyltrimethyl ammonium hydroxide (ETMAH). 
     
     
         6 . The porous silver powder of  claim 1 , wherein an average particle size D50 of the porous silver powder is in a range of 100 to 20,000 nm. 
     
     
         7 . The porous silver powder of  claim 1 , wherein a porosity is in a range of 5 to 50% and a specific surface area (BET) is in a range of 4.0 to 8.0 m 2 /g. 
     
     
         8 . The porous silver powder of  claim 1 , wherein an atomic ratio between silver (Ag) and the alloying element contained in the alloy powder is 1:9 or 8:2. 
     
     
         9 . A preparation method of the porous silver powder of  claim 1 , comprising:
 preparing a master alloy containing silver (Ag) and an alloying element other than silver (Ag);   manufacturing an alloy casting by dissolving and rapidly solidifying the master alloy;   grinding the alloy casting into alloy powder; and   removing at least part of the alloying element by etching the alloy powder with an acid solution or a basic solution.   
     
     
         10 . The preparation method of  claim 9 , wherein the rapidly solidifying of the master alloy is carried out by melt spinning, wherein, in the melt spinning, an average cooling rate is 10 6  to 10 8 ° C./sec. 
     
     
         11 . The porous silver powder of  claim 2 , wherein the alloying element comprises at least one material selected from the group consisting of silicon (Si), bismuth (Bi), germanium (Ge), copper (Cu), iron (Fe), nickel (Ni), chromium (CR), and cobalt (Co). 
     
     
         12 . The porous silver powder of  claim 11 , wherein the alloying element further comprises at least one transition metal element. 
     
     
         13 . The porous silver powder of  claim 2 , wherein the basic solution comprises at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, an ammonia solution, zinc chloride, tetramethyl ammonium hydroxide (TMAH), and ethyltrimethyl ammonium hydroxide (ETMAH). 
     
     
         14 . The porous silver powder of  claim 2 , wherein an average particle size D 50  of the porous silver powder is in a range of 100 to 20,000 nm. 
     
     
         15 . The porous silver powder of  claim 2 , wherein a porosity is in a range of 5 to 50% and a specific surface area (BET) is in a range of 4.0 to 8.0 m 2 /g. 
     
     
         16 . The porous silver powder of  claim 2 , wherein an atomic ratio between silver (Ag) and the alloying element contained in the alloy powder is 1:9 or 8:2. 
     
     
         17 . A preparation method of the porous silver powder of  claim 2 , comprising:
 preparing a master alloy containing silver (Ag) and an alloying element other than silver (Ag);   manufacturing an alloy casting by dissolving and rapidly solidifying the master alloy;   grinding the alloy casting into alloy powder; and   removing at least part of the alloying element by etching the alloy powder with an acid solution or a basic solution.   
     
     
         18 . The preparation method of  claim 17 , wherein the rapidly solidifying of the master alloy is carried out by melt spinning, wherein, in the melt spinning, an average cooling rate is 10 6  to 10 8 ° C./sec.