Thermal treatment method of tantalum powder

A heat treatment method and vacuum heat treatment technology, applied in the field of tantalum powder production, can solve the problems of low porosity, high oxygen content of tantalum powder, uncontrollable intense oxidation, etc., and achieve the effects of low leakage current, low oxygen content and high specific volume

Active Publication Date: 2011-07-13
NINGXIA ORIENT TANTALUM IND
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The present inventors have surprisingly found in in-depth research that the tantalum powder has a great relationship to the performance of the heat-treated tantalum powder in the state of heat treatment charging. If the tantalum powder is piled up too thick and the porosity is low, it will cause partial overoxidation of the tantalum powder; another

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  • Thermal treatment method of tantalum powder
  • Thermal treatment method of tantalum powder
  • Thermal treatment method of tantalum powder

Examples

Experimental program
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Effect test

Embodiment

[0047] Embodiment 1-1, Embodiment 1-2, Embodiment 1-3, Embodiment 1-4, Embodiment 1-5 and Embodiment 1-6, experiment on the thickness of tantalum powder charge in vacuum heat treatment stage

[0048] With a specific surface area of ​​1.6m 2 / g, bulk density is 0.57g / cm 3 , has a porosity of 96.56%, and its oxygen content is the original tantalum powder prepared by sodium reduction potassium fluorotantalate of 4800ppm, mixed with 80ppm of phosphorus by weight of the tantalum powder, spheroidized and granulated, and the bulk density obtained is 1.08g / cm 3 granulated tantalum powder. After the above-mentioned spheroidized and granulated tantalum powder was gently poured into a tantalum crucible of 350mm×210mm×75mm, the tantalum powder in the crucible had a porosity of 93.2% (96.52% of the porosity of the original tantalum powder). In embodiment 1-1, embodiment 1-2, embodiment 1-3, embodiment 1-4, embodiment 1-5 and embodiment 1-6, the thickness of tantalum powder in the cruci...

Embodiment 2-1、 Embodiment 2-2、 Embodiment 2-3、 Embodiment 2-4 and Embodiment 2-5

[0061] Example 2-1, Example 2-2, Example 2-3, Example 2-4 and Example 2-5, the influence of packing density / porosity of tantalum powder in vacuum heat treatment stage

[0062] Embodiment 2-1, embodiment 2-2, embodiment 2-3, embodiment 2-4 and embodiment 2-5 use the same raw material tantalum powder with a porosity of 96.56% as embodiment 1-1, carry out Spheroidizing and granulating to obtain a bulk density of 1.08g / cm 3 The granulated tantalum powder is packed into a vacuum heat treatment crucible so that the thickness of the tantalum powder is 51mm. Embodiment 2-1 is to pour tantalum powder into a vacuum heat treatment crucible gently, and its porosity is 93.49%, which is 96.8% of the original tantalum powder porosity; embodiment 2-2 is to pour tantalum powder into a vacuum heat treatment crucible , shake the crucible gently, the packing density of tantalum powder is 1.13g / cm 3 , the porosity is 93.19%, which is 96.51% of the porosity of the original tantalum powder; in emb...

Embodiment 3-1、 Embodiment 3-2

[0076] Embodiment 3-1, embodiment 3-2, embodiment 3-3 and embodiment 3-4, the impact of deoxidation heat treatment tantalum powder charging thickness on the performance of tantalum powder

[0077] With a specific surface area of ​​0.95m 2 / g, bulk density is 1.82g / cm 3 (with a porosity of 89.04%), the heat-treated sodium-reduced tantalum powder with an oxygen content of 5600ppm and a N content of 90ppm is mixed with 1.6% magnesium powder by weight of the tantalum powder to form a mixed powder, and the above mixed powder is loaded into a deoxidized In the heat treatment crucible, the charging thicknesses of the powders in Example 3-1, Example 3-2, Example 3-3 and Example 3-4 are respectively 35mm, 45mm, 55mm and 75mm, respectively having 87.9%, 88.3% , 88.8% and 88.5% porosity, respectively 98.7%, 99.2%, 99.7% and 99.4% of the original tantalum powder porosity. Carry out deoxidation heat treatment and follow-up treatment according to the condition of embodiment 1-1, obtain em...

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Abstract

The invention relates to a thermal treatment method of tantalum powder. The method comprises the following stages: (1) a vacuum thermal treatment stage: placing the raw tantalum powder with the porosity of 80-98% into a crucible in such a manner that the thickness of the tantalum powder in the crucible is less than 60 mm; heating the crucible in a heating furnace in vacuum at 900-1,400 DEG C; andthen cooling the crucible to the room temperature and passivating the tantalum powder to obtain the condensed tantalum powder; and (2) a deoxidization thermal treatment stage: uniformly mixing the condensed tantalum powder obtained in the stage (1) with a reducing agent to obtain the mixed powder; placing the mixed powder in the crucible in such a manner that the thickness of the mixed powder in the crucible is less than 60 mm; heating the crucible in a heating furnace in vacuum or inert atmosphere at 700-1,100 DEG C; then cooling the crucible to the room temperature and passivating the obtained tantalum powder; performing pickling to remove the residual reducing agent; and drying and screening to obtain the tantalum powder suitable for an electrolytic capacitor. The tantalum powder prepared by the method provided by the invention has low oxygen content and good electrical performance.

Description

technical field [0001] The invention relates to the field of tantalum powder production, and more specifically relates to a heat treatment method for tantalum powder used in electrolytic capacitors. Background technique [0002] The largest use of metal tantalum is to make tantalum electrolytic capacitors. The manufacturing process of tantalum electrolytic capacitors is usually to press tantalum powder in a die to form a compact, sinter the compact in a vacuum furnace to form a porous body with interconnected particles, and then anode the porous sintered body in a suitable electrolyte. Oxidation to form a uniform interconnected dielectric oxide film on the surface of the porous body, that is, to form an anode, and then coat the cathode material on the surface of the oxide film, and then encapsulate and form the capacitor anode and cathode. The parameters for evaluating tantalum electrolytic capacitors mainly include capacitance, DC (direct current) leakage current and equiv...

Claims

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Application Information

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IPC IPC(8): B22F1/00
Inventor 陈林冒海红董学成程越伟任萍雒国清林辅坤王治道张学清梁宏原王志清王秋迎
Owner NINGXIA ORIENT TANTALUM IND
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