High capacitance tantalum flakes and methods of producing the same

A technology of permittivity and sheet thickness, applied in the field of high capacitance tantalum sheet and its preparation, tantalum flake powder

Inactive Publication Date: 2007-08-01
CABOT CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there is a general lack of guidance in the art as to how thick a tantalum sheet should be used to ensure a specific capacitance at a specific formation voltage

Method used

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  • High capacitance tantalum flakes and methods of producing the same
  • High capacitance tantalum flakes and methods of producing the same
  • High capacitance tantalum flakes and methods of producing the same

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Experimental program
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Embodiment 1

[0059] In order to obtain a tighter flake thickness distribution and a lower average flake thickness, various samples were prepared using the standard starting material Kdel tantalum powder, which is a basic lot powder (basic lotpowder) that has undergone sodium reduction and acid leaching. Used to make C275Ta pellets from Cabot Corporation. 5 lbs of Kdel tantalum was slowly added to a 1S attritor mill with 50 lbs of 3 / 16" stainless steel media and 2700 ml of ethanol. After 2 hours of grinding at 250 rpm, the powder was removed from the mill. After the stainless steel media replaced the 3 / 16" media, the grinder was loaded with 2700ml of fresh ethanol and 2.5 lbs of powder ground from the 3 / 16". After milling at 250 rpm for 6 hours, the flakes were then removed and rinsed with DI water. The flakes are then subjected to acid leaching to remove surface contamination accumulated during grinding. Analyze the Scott density and chemical composition of the flake samples.

[0060] T...

Embodiment 2

[0064] C275 tantalum flakes commercially available from Cabot Corporation were compared with tantalum flakes prepared by multi-stage milling. In an embodiment, flakes of the present invention were prepared using a 2-stage milling process. 5 lbs of Kdel tantalum base batch powder, standard starting material for C275 Cabot flakes, were milled in a 1S attritor mill using 3 / 16 inch media at 250 rpm for 2 hours (first stage). Then, 2.5 lbs of ground material was ground for an additional 6 hours in the same grinder using 1 / 8 inch media (second stage). Then, the 2-stage milled flake samples were subjected to acid leaching and drying. Next, the flake samples were hydrogenated to a hydrogen content of 4000 ppm and ground in a Vortec mill to reduce the Scott density from about 4-5 g / in 3 Increase to about 20-25g / inch 3 . The samples were then processed using the standard C275 process with adjusted heat treatment temperatures of 1200°C and 1300°C for the first heat treatment and the ...

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Abstract

Methods of maximizing a tantalum capacitor's capacitance are disclosed, as well as tantalum flake powder and anodes. A two step milling process can be used to mill tantalum particles into tantalum flake powder having flakes of the desired thickness. This flake powder can then be pressed and sintered thereby forming an anode. Other flake capacitance methods and products are also disclosed.

Description

[0001] This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 60 / 583,498, filed June 28, 2004, the entire contents of which are hereby incorporated by reference. Background technique [0002] The invention relates to a high-capacity tantalum sheet and a preparation method thereof. The invention also relates to capacitors and anodes. [0003] With the ever-increasing demand for capacitor materials such as tantalum, it is highly desirable to ensure maximum capacitance per cell of capacitor material. Tantalum capacitors are usually prepared by pressing tantalum powder into pellets, sintering the pellets to form a porous tantalum body (electrode), and then anodizing the porous body in a suitable electrolyte to form a continuous dielectric oxide film on the sintered body . [0004] The amount of electricity that can be stored in a capacitor (hereinafter denoted CV) is the capacitor capacitance multiplied by the voltage. The CV (in μFV...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F1/00B22F9/24C22C1/04H01G9/042B22F1/052B22F1/068
CPCB22F1/0014B22F2998/10H01G9/0525H01G9/042B22F1/0055B22F2998/00C22C1/045C22C27/02B22F1/052B22F1/068B22F9/20B22F9/04
Inventor 邱永坚
Owner CABOT CORP
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