US2017069429A1PendingUtilityA1

Low Energy Milling to Produce Flake Powders

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Assignee: KEMET ELECTRONICS CORPPriority: Mar 13, 2013Filed: Oct 31, 2016Published: Mar 9, 2017
Est. expiryMar 13, 2033(~6.6 yrs left)· nominal 20-yr term from priority
Inventors:Brady JonesMatthew W. DufurJames Allan Fife
B22F 1/05B22F 1/068B22F 2009/043B22F 9/04C22C 30/00B02C 17/00H01G 9/042H01G 9/15H01G 9/0029Y10T428/12014C22C 27/02H01G 9/0525B22F 2998/10B22F 2301/20H01G 2009/05B22F 1/0011
53
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Claims

Abstract

A method for increasing surface area of a valve metal particle is provided as is an improved valve metal particle provided thereby. The method includes charging a mill apparatus with a valve metal powder and a media wherein the media has an average diameter of at least 0.01 cm to no more than 0.3175 cm. The valve metal powder is then milled at an average kinetic energy of no more than 3,000 ergs per media particle to obtain a milled powder.

Claims

exact text as granted — not AI-modified
1 . A method for increasing surface area of a valve metal particle comprising:
 charging a mill apparatus with a valve metal powder and a media wherein said media has an average diameter of at least 0.01 cm to no more than 0.3175 cm;   milling at an average kinetic energy of no more than 3,000 ergs per media particle to obtain a milled powder.   
     
     
         2 . The method for increasing surface area of a valve metal particle of  claim 1  comprising milling at an average kinetic energy of no more than 1,000 ergs per media particle. 
     
     
         3 . The method for increasing surface area of a valve metal particle of  claim 2  comprising milling at an average kinetic energy of no more than 100 ergs per media particle. 
     
     
         4 . The method for increasing surface area of a valve metal particle of  claim 3  comprising milling at an average kinetic energy of no more than 5 ergs per media particle. 
     
     
         5 . The method for increasing surface area of a valve metal particle of  claim 4  comprising milling at an average kinetic energy of no more than 2 ergs per media particle. 
     
     
         6 . The method for increasing surface area of a valve metal particle of  claim 5  comprising milling at an average kinetic energy of no more than 2 ergs per media particle. 
     
     
         7 . The method for increasing surface area of a valve metal particle of  claim 6  comprising milling at an average kinetic energy of no more than 1 erg per media particle. 
     
     
         8 . The method for increasing surface area of a valve metal particle of  claim 1  wherein said valve metal powder is selected from the group consisting of tantalum, niobium, tungsten, titanium, aluminum and alloys thereof. 
     
     
         9 . The method for increasing surface area of a valve metal particle of  claim 8  wherein said valve metal powder is tantalum. 
     
     
         10 . The method for increasing surface area of a valve metal particle of  claim 1  wherein said media comprises a material selected from the group consisting of steel, zirconia, yttria stabilized zirconia, 440 stainless steel, glass, tungsten carbide, tantalum, niobium, tantalum nitride, niobium nitride, tantalum carbide and mixtures thereof. 
     
     
         11 . The method for increasing surface area of a valve metal particle of  claim 1  wherein said media is spherical. 
     
     
         12 . The method for increasing surface area of a valve metal particle of  claim 1  wherein said milled powder has a BET surface area of greater than 4 M 2 /g. 
     
     
         13 . The method for increasing surface area of a valve metal particle of  claim 12  wherein said milled powder has a BET surface area of greater than 5 M 2 /g. 
     
     
         14 . The method for increasing surface area of a valve metal particle of  claim 13  wherein said milled powder has a BET surface area of greater than 6 M 2 /g. 
     
     
         15 . The method for increasing surface area of a valve metal particle of  claim 14  wherein said milled powder has a BET surface area of greater than 7 M 2 /g. 
     
     
         16 . The method for increasing surface area of a valve metal particle of  claim 15  wherein said milled powder has a BET surface area of greater than 8 M 2 /g. 
     
     
         17 . The method for increasing surface area of a valve metal particle of  claim 16  wherein said milled powder has a BET surface area of greater than 9 M2/g. 
     
     
         18 . The method for increasing surface area of a valve metal particle of  claim 1  wherein said milled powder no more than 30 ppm metallic impurity. 
     
     
         19 . The method for increasing surface area of a valve metal particle of  claim 1  wherein said milled powder no more than 30 ppm impurity selected from iron, nickel and chromium. 
     
     
         20 . The method for increasing surface area of a valve metal particle of  claim 1  wherein said milled powder has no more than 30 ppm impurity selected from iron, nickel, chromium, silicon and zirconium. 
     
     
         21 . The method for increasing surface area of a valve metal particle of  claim 1  wherein said valve metal powder has a CV/g of less than 30,000 micro-farad volts per gram. 
     
     
         22 . The method for increasing surface area of a valve metal particle of  claim 21  wherein said valve metal powder has a CV/g of less than 50,000 micro-farad volts per gram. 
     
     
         23 . The method for increasing surface area of a valve metal particle of  claim 22  wherein said valve metal powder has a CV/g of less than 100,000 micro-farad volts per gram. 
     
     
         24 . The method for increasing surface area of a valve metal particle of  claim 1  wherein said milled powder has a CV/g of at least 180,000 micro-farad volts per gram. 
     
     
         25 . The method for increasing surface area of a valve metal particle of  claim 24  wherein said milled powder has a CV/g of at least 200,000 micro-farad volts per gram. 
     
     
         26 . The method for increasing surface area of a valve metal particle of  claim 25  wherein said milled powder has a CV/g of at least 250,000 micro-farad volts per gram. 
     
     
         27 . The method for increasing surface area of a valve metal particle of  claim 1  wherein said average kinetic energy is achieved at a rotation rate of a drive shaft of no more than 120 RPM. 
     
     
         28 . The method for increasing surface area of a valve metal particle of  claim 1  wherein said mill apparatus is selected from the group consisting of attritor mill, jar mill, vibratory ball mill and a horizontal stirred ball mill. 
     
     
         29 . A valve metal powder formed by the method of  claim 1 . 
     
     
         30 . (canceled) 
     
     
         31 . A valve metal powder comprising:
 a CV/g of at least 30,000 micro-farad volts per gram;   a BET surface area of greater than 4 M 2 /g; and   an aspect ratio of at least 3.   
     
     
         32 . The valve metal powder of  claim 31  with an aspect ratio of at least 10. 
     
     
         33 . The valve metal powder of  claim 32  with an aspect ratio of at least 100. 
     
     
         34 . The valve metal powder of  claim 30  with an aspect ratio of at least 200. 
     
     
         35 . The valve metal powder of  claim 31  with an aspect ratio of no more than 300. 
     
     
         36 . The valve metal powder of  claim 31  comprising no more than 30 ppm metallic impurity. 
     
     
         37 . The valve metal powder of  claim 31  comprising no more than 30 ppm impurity selected from iron, nickel, chromium, silicon and zirconium. 
     
     
         38 . The valve metal powder of  claim 37  comprising no more than 30 ppm impurity selected from iron, nickel and chromium. 
     
     
         39 . The valve metal powder of  claim 31  wherein said valve metal powder is selected from the group consisting of tantalum, niobium, tungsten, titanium, aluminum and alloys thereof. 
     
     
         40 . The valve metal powder of  claim 39  wherein said valve metal powder is tantalum. 
     
     
         41 . The valve metal powder of  claim 40  wherein said milled powder has a BET surface area of greater than 5 M 2 /g. 
     
     
         42 . The valve metal powder of  claim 41  wherein said milled powder has a BET surface area of greater than 6 M 2 /g. 
     
     
         43 . The valve metal powder of  claim 42  wherein said milled powder has a BET surface area of at least 7 M 2 /g. 
     
     
         44 . The valve metal powder of  claim 43  wherein said milled powder has a BET surface area of at least 8 M 2 /g. 
     
     
         45 . The valve metal powder of  claim 44  wherein said milled powder has a BET surface area of at least 9 M 2 /g. 
     
     
         46 . The valve metal powder of  claim 31  wherein said milled powder has a CV/g of at least 180,000 micro-farad volts per gram. 
     
     
         47 . The valve metal powder of  claim 46  wherein said milled powder has a CV/g of at least 200,000 micro-farad volts per gram. 
     
     
         48 . The valve metal powder of  claim 47  wherein said milled powder has a CV/g of at least 250,000 micro-farad volts per gram. 
     
     
         49 - 61 . (canceled)

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