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A kind of heat treatment method of tantalum powder

A heat treatment method, tantalum powder technology, applied in transportation and packaging, electrolytic capacitors, capacitors, etc., can solve the problems of high oxygen content of tantalum powder, large temperature difference, small temperature rise of tantalum powder, etc., to achieve uniform particle oxygen content, Oxygen content deviation is small and the effect of avoiding intense oxidation

Active Publication Date: 2019-08-23
江门富祥电子材料有限公司
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Problems solved by technology

Moreover, the tantalum oxide film formed at a lower temperature is amorphous, thin and dense; while the tantalum oxide film formed at a higher temperature is thicker, and there will be crystallization, and the oxygen content of the tantalum powder high
[0006] In recent years, people have studied the technology of passivating tantalum powder with higher specific surface area, such as Chinese patents CN103429782B and CN102181818B, which passivate the surface of tantalum powder after heat treatment. This technology has some effects in some cases However, there are still some defects: 1. Since the measured temperature is outside the tantalum crucible, when the temperature changes, the measured temperature will lag for several minutes; 2. When the temperature of a small local tantalum powder rises, due to The total heat is small, and the temperature difference is very large when it is transmitted to the temperature detector; 3. Due to the different temperatures of the tantalum powder in various places during passivation, the partial high temperature of the tantalum powder results in the intense oxidation of the local tantalum powder; 4. In the final stage of passivation of tantalum powder, due to the small temperature rise of tantalum powder, it is difficult to identify the completion of passivation of tantalum powder, which may cause insufficient passivation of tantalum powder
This shows that the temperature at the white spot is higher than that of other tantalum powder at the beginning, and the oxidation speed is faster, it is easier to absorb oxygen in the furnace to oxidize and release heat, and suddenly the temperature rises and even burns, so that the oxygen in the furnace is concentrated rapidly Go there until the oxygen in the furnace is almost completely consumed, resulting in a large temperature difference between the center of the crucible and the part outside the crucible where the temperature detector was placed before, that is to say, the sudden temperature rise when the tantalum powder is oxidized cannot be detected in time and accurately. High, resulting in local intense oxidation of tantalum powder, which is the defect in the prior art
[0008] In addition, during the final stage of passivation of tantalum powder, the temperature rises very little. If the temperature detector is a certain distance away from the tantalum powder, it is not easy to detect the temperature change, so it cannot be judged whether the tantalum powder has completely formed a dense oxide film , may cause insufficient passivation of tantalum powder

Method used

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  • A kind of heat treatment method of tantalum powder
  • A kind of heat treatment method of tantalum powder
  • A kind of heat treatment method of tantalum powder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0076] The tantalum powder prepared by reducing potassium fluorotantalate with sodium is washed with water, pickled with acid, washed with water and filtered, and the specific surface area after drying is 0.61m 2 / g, the oxygen content is 3050ppm, and the tantalum powder that nitrogen content is 80ppm is packed into tantalum crucible 4 lis, and the above-mentioned crucible 4 that tantalum powder is housed is packed again such as Figure 5 The heat treatment is carried out in the shown vacuum heat treatment furnace. The heat treatment furnace has a furnace shell 1 with a cooling water jacket 91 and a cooling water outlet 92. The inner and outer layers of the furnace are insulation screens composed of multi-layer heat-resistant metals. 2. Inside the insulation screen is a heater 3 made of high-temperature-resistant metals such as tantalum. Three layers of crucibles 4 are placed in the heater. row, 3 in each row, a total of 27 tantalum crucibles, a bendable thermocouple T i1 51 ...

Embodiment 2

[0084] use as Figure 6 In the passivation device shown, the specific surface area obtained after heat treatment of 130kg is 0.428m 2 / g, tantalum powder with an oxygen content of 4010ppm and a nitrogen content of 110ppm, add 2080 grams of magnesium powder, mix the magnesium powder and tantalum powder evenly, put them into 11 tantalum crucibles 17, and put 3 bendable thermocouples 3A , 3B and 3C are respectively placed on the tantalum powder 16 in the center of the bottom layer of the tantalum crucible, the sixth layer of the tantalum crucible and the top layer of the tantalum crucible (the three thermocouples of 3A, 3B and 3C are distributed in the reactor On a concentric circle of the outer circle of the cover, there is an included angle of about 10° to 15° between 3A and 3B and 3B and 3C, Figure 6 The middle thermocouples 3A, 3B and 3C just mean that three thermocouples are placed in tantalum crucibles of different heights from the reactor cover downwards), and the materi...

Embodiment 3

[0094]The oxygen content that has carried out deoxidation treatment with embodiment 2 is 2000ppm, and specific surface area is 0.42m 2 / g of tantalum powder is used as the raw material of the capacitor anode, and 0.21mm tantalum wire is used as the lead wire to bury it in the tantalum powder. Each anode block uses 1.245 grams of tantalum powder and presses it into a cylinder with a diameter of 6 mm and a thickness of 8 mm. The density of tantalum pressing is about 5.5g / cm 3 Put the compact into a tantalum crucible, place a thermocouple on the tantalum anode compact, put the tantalum compact into a vacuum sintering furnace for sintering, and evacuate until the vacuum degree reaches 1×10 －5 Torr, heat up to 1480°C for sintering for 20 minutes, then power off to cool down to 25°C. Since the sintered tantalum block is relatively large, it is difficult to dissipate the internal heat during passivation. The passivation treatment is carried out with argon and air cooled to about -5°...

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Abstract

The invention relates to a heat treatment method for tantalum powder, which is characterized in that when the tantalum powder is heat-treated in a vacuum container, at least two temperature detectors are brought into contact with the tantalum powder to be processed, and after the tantalum powder is heat-treated, the temperature is lowered to 35°C or Below, and the temperature difference between any two places is lower than 3°C, feed oxygen-containing gas into the vacuum container, and control the amount of oxygen-containing gas introduced, so that when the surface of tantalum powder is oxidized, the temperature of tantalum powder will not rise higher than 10°C continuously . The obtained tantalum powder product has low oxygen content, uniform oxygen content among particles, and good electrical performance.

Description

technical field [0001] The present invention relates to a heat treatment method for tantalum powder. Specifically, during the heat treatment of tantalum powder, at least two temperature detectors are brought into contact with the tantalum powder to be processed. , to passivate tantalum powder. Background technique [0002] The largest use of tantalum powder is to manufacture tantalum electrolytic capacitors. The tantalum sintered body electrochemically reacts in the electrolyte to form an amorphous tantalum oxide film, which is used as the dielectric layer of the anode and cathode of the capacitor. As the main raw material of tantalum electrolytic capacitors, the impurity content of capacitor-grade tantalum powder, especially the oxygen content, has a great influence on the leakage current. Also, if the tantalum powder is composed of particles with uneven oxygen content, such tantalum powder is in After the sintered body obtained by sintering forms an anode, crystalline tan...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F1/00H01G9/042H01G9/052
CPCH01G9/042H01G9/0525B22F1/142B22F1/145
Inventor 郑浩宇廖志刚朱德忠
Owner 江门富祥电子材料有限公司
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