CN102120258B - Thermal treatment method of tantalum powder - Google Patents
Thermal treatment method of tantalum powder Download PDFInfo
- Publication number
- CN102120258B CN102120258B CN 201110039272 CN201110039272A CN102120258B CN 102120258 B CN102120258 B CN 102120258B CN 201110039272 CN201110039272 CN 201110039272 CN 201110039272 A CN201110039272 A CN 201110039272A CN 102120258 B CN102120258 B CN 102120258B
- Authority
- CN
- China
- Prior art keywords
- tantalum powder
- powder
- crucible
- porosity
- tantalum
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Powder Metallurgy (AREA)
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; and then 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
The present invention relates to tantalum powder production field, and more specifically relate to the heat treatment method of electrolytic capacitor with the tantalum powder.
Background technology
The maximum purposes of metal tantalum is to make tantalum electrolytic capacitor.The manufacture process of tantalum electrolytic capacitor is normally suppressed in pressing mold with the tantalum powder and is formed briquet; Sintering briquet between particle interconnective porous body in the vacuum drying oven; Then above-mentioned porous sintered body is carried out anodic oxidation in suitable electrolyte, make the porous body surface form the dielectric oxide film that interconnects uniformly, promptly form anode; At the surface-coated cathode material of oxide-film, seal and form capacitor anode and negative electrode then again.The parameter of estimating tantalum electrolytic capacitor mainly contains capacitance, DC (direct current) leakage current and equivalent series resistance (ESR).The development trend of capacitor is to have high capacitance, low leakage current and low equivalent series resistance.Impurity content as the Ta powder used in capacitor of the primary raw material of tantalum electrolytic capacitor; Particularly oxygen content is very big to the influence of leakage current; The tantalum powder of too high oxygen content has crystallized tantalum oxide to separate out after the sintered body that is sintered forms anode, and the tantalum-oxide film withstand voltage properties is poor, and leakage current is high.In general, the specific area of tantalum powder is high more, and oxygen content is also high more, expects that usually the oxygen content of Ta powder used in capacitor is calculated not above 3300ppm/m according to per surface area
2Be used to make the tantalum powder of electrolytic capacitor, the leakage current of tantalum anode can not be too high, is that the leakage current of 65000～75000 μ FV/g tantalum powder should not be higher than 30 μ A/g like specific volume.
The method of making Ta powder used in capacitor has two types usually, one type be with electronic torch melting tantalum ingot or electric arc melting tantalum ingot through the over hydrogenation grinding flour, vacuum heat is carried out dehydrogenation heat treatment more then.Another kind of method is to contain tantalum compound with the reducing agent reduction, and the salt grumeleuse that melts that contains the tantalum powder that obtains obtains former fecula (without heat treatment) through washing, pickling leaching, carries out vacuum heat and deoxidation heat treatment then.The described heat treatment of this specification is meant the tantalum powder is placed the process that under the temperature more than 300 ℃, heats in vacuum or the reducing atmosphere, comprises the sintering of above-mentioned two kinds of heat treatments and tantalum powder briquet.
The tantalum powder of using as electrolytic capacitor; Usually all will carry out vacuum heat, on the one hand the tantalum powder purified, be to make fine tantalum particle coacervation become the flocculated particle of porous on the other hand; Improve the physical characteristic of tantalum powder; Like the flowability of tantalum powder, thereby improve performance, like capacitor volume, leakage current and equivalent series resistance (ESR) with the electrolytic capacitor of its manufacturing.Early stage heat treatment such as U.S. Pat 3473915 disclosed heat treatments are that the tantalum powder with average grain diameter 2～30 μ m carries out heat-coagulation at 1200 ℃～1500 ℃ and handles under non-activity atmosphere, form the multiple-contact porous particle of adhesion, obtain condensing the tantalum powder.The tantalum powder producer and capacitor manufacturer have been carried out number of research projects to the heat treatment of tantalum powder in the process of exploitation high specific surface area tantalum powder and midget capacitor in recent decades.In order to reach good flocculating result, when packing the tantalum powder into the heat treatment crucible, make porosity less more favourable, disclose like US6479012B2 and the tantalum powder is added water form wet powder, and vibrated and form closely knit tantalum muffin piece, grind after the heat treatment and obtain the tantalum powder.The density of this method oven dry back gained tantalum muffin piece is 2.3g/cm
3More than, its porosity has only 83%, is below 86% of former tantalum powder porosity approximately.Grind after the heat treatment and obtain the tantalum powder.Carrying out change (cohesion) heat treatment technics about the tantalum powder also can be referring to flat 2-34701 of Japanese documentation TOHKEMY and the flat 4-362101 of TOHKEMY; Wherein disclosed tantalum powder heat treatment technics is the tantalum powder to be immersed in the water form slurry; Remove moisture with centrifugation and form tantalum cake piece; Heat-treat after the oven dry, the tantalum cake piece porosity that obtains like this is below 85% of former tantalum powder porosity below 80% approximately again.The heat treatment method of above-mentioned these two kinds of tantalum powder is big to the specific area loss of tantalum powder, and oxygen content is high.The condenser capacity that makes with such tantalum powder is low, and leakage current is high.
An amount of reducing agent alkaline-earth metal or rare earth metal or its hydride are normally sneaked in tantalum powder deoxidation heat treatment in the tantalum powder, in vacuum or inert atmosphere, heat-treat at 700 ℃～1100 ℃, make the tantalum powder obtain condensing and removing oxygen.
Because the tantalum metal is a kind of and the very big metal of oxygen affinity, tantalum and oxidation are closed and formed tantalum pentoxide is exothermic reaction, and there is one deck dense oxidation film on the surface of tantalum powder, can prevent the continuation oxidation of tantalum.The tantalum particle one that this oxidized film covers is when being heated to about temperature more than 300 ℃, and tantalum-oxide film ftractures and is destroyed, and partial oxygen is dissolved in the tantalum matrix, partial oxygen loss, enrichment.And when the tantalum powder after the heating contacts with oxygen-containing medium in the back that is cooled, begin oxidation again from the surface, even cause the spontaneous combustion of tantalum powder, so people have developed the passivating technique of tantalum powder controllable oxidization.The passivation of described tantalum powder is when after the oxide-film of tantalum powder is destroyed, contacting with oxygen-containing medium again; Control the feed speed of oxygen artificially; Thereby the oxidation rate and the temperature of control tantalum powder under controlled situation make tantalum powder surface form the passive oxidation film, avoid fierce oxidation.So specific area is at 0.2m
2The above tantalum powder of/g will carry out Passivation Treatment usually after heat treatment.
Along with the development of the miniaturization of electronic devices and components, require to use to have the finer tantalum powder of bigger serface.For the tantalum powder of high-specific surface area, because the heat that produces during in passivation at the tantalum powder in the unit volume scope is more, temperature is also higher.It is thicker under higher temperature, to form tantalum-oxide film, and the oxygen content of tantalum powder is high.If the passivation of tantalum powder is insufficient, the fierce oxidation of meeting when the tantalum powder is taken out in heat-treatment furnace, even can cause that the tantalum powder catches fire.In a single day the tantalum powder catches fire, and will bring about great losses.
In the existing tantalum powder heat treatment technics, the state of charge in the heat treatment of tantalum powder is not scrutinized.The inventor is surprised to find in further investigation, and the tantalum powder can have very big relation in the heat treatment state of charge to heat treatment tantalum mealiness, and too thick if the tantalum powder is piled up, porosity is low, will cause the local peroxidating of tantalum powder; On the other hand, inappropriate if the tantalum powder loads when heat treatment, can cause that then the passivation of tantalum powder is insufficient, after the tantalum pruinescence took out in the vacuum drying oven, uncontrollable fierce oxidation also can take place, make that the oxygen content of tantalum powder is high, sometimes even can cause and catch fire.
Therefore this area still needs the method that can heat-treat safely the tantalum powder.
Summary of the invention
The purpose of this invention is to provide a kind of method that the tantalum powder is heat-treated, this method is not only as safe as a house, and can avoid local peroxidating or the inadequate problem of passivation.
The present invention provides a kind of heat treatment method of tantalum powder to realize above-mentioned purpose, and this method comprises following the processing stage:
(1) the vacuum heat stage: with porosity is 80～98% the former tantalum powder crucible of packing into, makes in the crucible that the thickness of tantalum powder is below the 60mm and its porosity is more than 95% of former tantalum powder porosity; Place heating furnace under 900 ℃～1400 ℃ temperature, to heat in a vacuum then; Be cooled to room temperature subsequently and gained tantalum powder is carried out Passivation Treatment, obtain condensing the tantalum powder; With
(2) deoxidation heat treatment stages: higher cohesion tantalum powder and even the mixing of reducing agent of oxygen content that the stage (1) is obtained obtains mixed-powder; Said mixed-powder is packed in the crucible, make in the crucible that the thickness of mixed-powder is below the 60mm and its porosity is more than 98% of former tantalum powder porosity; Place heating furnace under 700 ℃～1100 ℃ temperature, to heat then in vacuum or inert atmosphere; Be cooled to room temperature subsequently and gained tantalum powder is carried out Passivation Treatment; Thereby the tantalum powder that remaining reducing agent and dried and screened obtain being applicable to electrolytic capacitor is removed in pickling.
In a preferred embodiment of the inventive method, in the said vacuum heat stage (1), the porosity of the tantalum powder in the crucible of packing into is more than 98% of former tantalum powder porosity, and more preferably 99%～100%.
In another preferred embodiment of the inventive method, in the said vacuum heat stage (1), the thickness of tantalum powder is 40～50mm in the crucible.
In another preferred embodiment of the inventive method, in the said vacuum heat stage (1), be 30～90 minutes heat time heating time.
In a preferred embodiment of the inventive method, wherein in said deoxidation heat treatment stages (2), described reducing agent is selected from alkaline-earth metal, rare earth metal and hydride thereof.In the more preferred of the inventive method, wherein said reducing agent is the magnesium powder.
In another preferred embodiment of the inventive method, wherein in said deoxidation heat treatment stages (2), the porosity of the mixed-powder in the crucible of packing into is more than 98% of former tantalum powder porosity, and more preferably 99%～100%.
In a preferred embodiment of the inventive method, wherein in said deoxidation heat treatment stages (2), the thickness of mixed-powder is 40～60mm in the crucible.
In another preferred embodiment of the inventive method, wherein in said deoxidation heat treatment stages (2), be 1～6 hour heat time heating time.
According to the tantalum powder that the inventive method is heat-treated, the oxygen content of tantalum powder is low, and the tantalum powder takes out the fierce oxidation in back from heat-treatment furnace problem can not occur.According to the tantalum powder that the inventive method is heat-treated, tantalum powder specific volume is high, and leakage current is low.
Should be appreciated that above generality is described and all be exemplary below in conjunction with the detailed description of accompanying drawing and the detailed description of preferred embodiment, its objective is and further explain the present invention for required protection, is not limitation of the present invention.
Description of drawings
Fig. 1 is the sketch map that the tantalum powder is carried out the used vacuum heat treatment furnace of vacuum heat according to method of the present invention.
Fig. 2 carries out the used schematic representation of apparatus of deoxidation heat treatment according to method of the present invention to the tantalum powder.
The specific embodiment
In this manual, only if offer some clarification in addition, " PPM " that the ppm of unit refers to represent with mass ratio.
The present invention provides a kind of heat treatment method of tantalum powder; Wherein said tantalum powder can be the former powder without Overheating Treatment of electronation, for example adopts the tantalum powder of sodium reduction potassium floutaramite preparation, the former powder that the tantalum ingot obtains through over hydrogenation powder process; Also can be through heat treated tantalum powder, be not limited thereto.Before heat treatment, preferably former powder is carried out granulation, preferred especially nodularization granulation is handled.Any shrinkage factor when helping controlling the tantalum powder at high temperature sintering that can in tantalum powder granulation process, add the ratio that requires is burnt agent with the chemical substance that reduces surface area losses as resistance, like the material of phosphorous, nitrogen, boron, oxygen.In the inventive method; Can adopt known technology; For example Chinese patent number is handled for disclosed the whole bag of tricks among CN1240688A, CN1382548A, CN1410209A, CN1238251A and the CN1899730A carries out granulation, and above-mentioned file is introduced the application as a reference in full.
According to the inventive method,, can be granular, sheet, polygonal or their combination in any for the not restriction of particle shape of the tantalum powder that will heat-treat.Specific area for the tantalum powder does not have special requirement yet, can be 0.1m
2/ g～10m
2/ g, preferred 0.3m
2/ g～5m
2/ g.
The porosity of the tantalum powder described in the present invention (former tantalum powder) is meant the ratio of the whole volume that pore volume and tantalum powder in the tantalum powder is shared, i.e. pore volume/(tantalum powder particles cumulative volume+pore volume).A simple method of calculating the porosity of tantalum powder is to calculate according to formula:
(1-Db/16.6)×100％
Db is apparent density (apparent density) value of tantalum powder in the formula, and unit is g/cm
3
The porosity that is loaded into the tantalum powder in the crucible also is to obtain according to following formula, and the apparent density of tantalum powder is divided by the shared volume (cm of tantalum powder with tantalum grain weight amount (g)
3).If lightly the tantalum powder is poured in the crucible, avoid vibration, then the porosity of its porosity and former tantalum powder is basic identical, and the porosity that promptly is loaded into the tantalum powder in the crucible is near 100% of former tantalum powder porosity.
Described tantalum powder heat treatment shove charge is meant packs the tantalum powder in the crucible into, puts into above-mentioned crucible in the vacuum heat treatment furnace according to certain method again.The instance of the vacuum heat treatment furnace that the present invention uses is as shown in Figure 1, and heat-treatment furnace comprises: burner hearth 110, the shell 111 of forming the band water-cooling jacket of said burner hearth 110, the pressure vacuum ga(u)ge 112 that communicates with burner hearth, the pipeline 141 of finding time, passivation with inlet 120, the argon gas of oxygen-containing gas enter the mouth 140, be positioned at thermocouple 160, the tantalum powder 170 of the heat protection screen 130 of burner hearth, the heater 150 that is positioned at heat protection screen 130, measurement temperature, the crucible 180 that holds heat treatment tantalum powder, the heat treatment crucible 180 that holds said tantalum powder 170 be placed in the thermal treatment zone of burner hearth 110.Consider that from the even adequacy of uniformity, nitriding and passivation of heating the tantalum powder of packing in each crucible is less for well; And consider from productivity ratio, should adorn as much as possible.According to the present invention, the tantalum powder in the crucible of packing into the thickness on the one dimension direction at least is 60mm or following, and for not only safe but also higher productivity ratio is arranged, the thickness of tantalum powder is preferably 40～50mm.The present invention adopts the more shallow circular or square crucible of the degree of depth usually, is respectively the crucible 180 of about 350mm * 210mm * 75mm like a plurality of length x width x depth that adopt.For fear of the pollution of tantalum powder when the heat treatment, adopt metal tantalum or tantalum alloy to process tantalum powder heat treatment crucible, pending tantalum powder 170 is loaded into 180 li in crucible, and upper surface is wipeed off, avoids vibration as far as possible.Higher porosity helps the diffusion of gaseous exchange and heat, promptly helps nitriding, the passivation of tantalum powder.According to the present invention, the porosity of the tantalum powder of the heat treatment crucible of packing into be former tantalum powder porosity 95% or more than, be preferably 98% or more than, more preferably 99～100%.Crucible divides multilayer to put in the vacuum drying oven, and the space between the bottom surface of the upper edge of following crucible and last layer crucible is about 3 centimetres.
The heat treated temperature of tantalum powder and temperature retention time are to confirm with requiring according to dissimilar tantalum powder, generally are lower than 1.33 * 10 at vacuum pressure
-1900 ℃～1400 ℃ are incubated 30～90 minutes in the vacuum of handkerchief.
The tantalum powder is through after 900 ℃～1400 ℃ insulations, in vacuum drying oven under the vacuum or/and feed argon gas and cool off, when cool to room temperature or after, carry out Passivation Treatment near room temperature.The Passivation Treatment of tantalum powder is that oxygen-containing gas is sent in the vacuum drying oven lentamente, and in several hours to tens of hours time period, makes in the vacuum drying oven from low oxygen concentration and change to the oxygen concentration the atmosphere.The used oxygen-containing gas of Passivation Treatment can be the mist of oxygen and inert gas (like nitrogen, argon gas, helium etc.).In preferred embodiments, use air (it is the mist of oxygen and nitrogen basically) to use oxygen-containing gas usually as passivation.When using air to carry out Passivation Treatment as oxygen-containing gas, initially feed the air of less flow, make that the oxygen partial pressure in the stove keeps reduced levels (for example 1.5Pa); In several hours to tens of hours time period, improve the dividing potential drop of oxygen then gradually, make that finally the oxygen partial pressure in the stove changes to the oxygen partial pressure in the atmosphere.
Tantalum powder after the heat treatment can randomly carry out nitriding in temperature-fall period.
After heat-treating according to the inventive method, analyze the oxygen content and the nitrogen content of gained tantalum powder, measure apparent density, specific area.The tantalum powder is after Overheating Treatment, and oxygen content increases, and therefore can carry out deoxidation treatment.
In reducing atmosphere, the tantalum powder is carried out deoxidation treatment; Usually; In the tantalum powder, sneak into a small amount of reducing agent bigger than the affinity of tantalum and oxygen with the affinity of oxygen, like alkaline-earth metal, rare earth metal and hydride thereof, the most frequently used is the metal magnesium powder of in the tantalum powder, sneaking into tantalum grain weight amount 0.5%～4%.
According to the inventive method, the porosity of carrying out the heat treated tantalum powder of deoxidation in the crucible of packing into be former tantalum powder porosity 95% or more than, preferred 98% or more than, more preferably 99%～100%.
Device shown in Figure 2 is according to the present invention the tantalum powder to be carried out the heat treated preferred embodiment of deoxidation; Said device comprises: the discharge duct 241 of finding time, pressure vacuum ga(u)ge 212 arranged on air-tightness reaction vessel 210, loam cake 211, the said loam cake 211, fill nitrogen admission line 242, passivation with oxygen-containing gas admission line 220, argon inlet pipe road 240, be placed on crucible 280 in the reactor, the tantalum powder 270 of 280 li in the said crucible of packing into and the heat protection screen on the tantalum powder crucible 250, measure on the reaction vessel respectively, in and the thermocouple 261,262 and 263 of the temperature of lower position; Wherein the diameter of tantalum system crucible 280 is about 500mm; Its degree of depth is about 80mm; The tantalum powder 270 of sneaking into the magnesium powder is loaded into respectively in above-mentioned a plurality of crucible, and its thickness is about 40～60mm; The crucible of tantalum powder is housed, and the distance between the bottom surface of the upper edge of following crucible and adjacent upward crucible is about 4 centimetres.
The mixed-powder of tantalum powder and reducing agent is placed crucible, and in the enclosed vacuum reactor of packing into, under inert atmosphere and/or vacuum, be heated to 700 ℃～1100 ℃ insulations 1～6 hour.
Can adopt nitridation technique well known to those skilled in the art, in tantalum powder deoxidation process, carry out nitriding.As adopt disclosed technology among Chinese patent CN101234425A, the CN101113510A.
In reactor, feed argon gas and cool off,, carry out Passivation Treatment when cool to room temperature or after near room temperature.
Tantalum powder after the deoxidation heat treatment is taken out, carry out pickling, washing, drying, sieving obtains the tantalum powder.Analyze the oxygen content and the nitrogen content of gained tantalum powder, measure its apparent density, BET specific area, and carry out the electrical property analysis.
The oxygen content of tantalum powder disclosed in this specification and nitrogen content data are to adopt TC-436 oxygen nitrogen combined measuring instrument to measure.The ASAP2021 type specific surface area measuring instrument that the BET specific surface area data of disclosed powder is to use Micromerities company to produce in this specification is measured.The apparent density of powder disclosed in this specification (SBD) is to test according to the method for CNS GB5060-85 regulation.The wet type electrical performance data of tantalum powder disclosed in this specification is to measure through following mode: it is 5.5g/cm that the tantalum powder is pressed into density
3, diameter 4.0mm, height is embedded with the cylindrical briquet of 0.3mm tantalum wire for 6.76mm, and each briquet contains the about 467mg of tantalum powder; Above-mentioned briquet formed agglomerate in 10 minutes at 1320 ℃ of sintering; Above-mentioned agglomerate is placed the phosphate aqueous solution of 80 ℃ 0.1 quality %; Current density up voltage with 150mA/g formed the anode that the tantalum particle surface is coated with the dielectric oxidation rete in 120 minutes to the 30V constant voltage; In the phosphoric acid of 25 ℃ 0.1 quality %, measure the anode leakage current, in 20 quality % sulfuric acid solutions, measure specific capacitance (specific volume) and loss.
In order to further specify the present invention, below in conjunction with embodiment and accompanying drawing the preferred embodiment of the invention is described, describe just to further specifying feature and advantage of the present invention but should be appreciated that these, rather than limitation of the scope of the invention.
Embodiment
Embodiment 1-1, embodiment 1-2, embodiment 1-3, embodiment 1-4, embodiment 1-5 and embodiment 1-6, the experiment of vacuum heat stage tantalum powder charging thickness
Use specific area to be 1.6m
2/ g, apparent density is 0.57g/cm
3, having 96.56% porosity, its oxygen content is the original tantalum powder of the sodium reduction potassium floutaramite preparation of 4800ppm, mixes the phosphorus by tantalum grain weight amount 80ppm, carries out the nodularization granulation, obtaining apparent density is 1.08g/cm
3Granulation tantalum powder.After above-mentioned nodularization granulation tantalum powder being poured into lightly in the tantalum crucible of 350mm * 210mm * 75mm, the tantalum powder in the crucible have 93.2% porosity (for former tantalum powder porosity 96.52%).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 crucible is about 30mm, 40mm, 50mm, 60mm, 70mm, 75mm respectively; Packing in the vacuum heat treatment furnace as shown in Figure 1, is 1.33 * 10 at pressure
-1Be heated to 1250 ℃ of insulations 30 minutes in the vacuum below the Pa; Cooling then feeds the argon gas cool to room temperature, uses air with oxygen-containing gas the tantalum powder to be carried out passivation as passivation subsequently; Then the tantalum powder after the passivation is taken out in heat-treatment furnace, the tantalum powder is poured out in crucible.With 80 mesh the tantalum powder is sieved; Obtain-80 purpose heat treatment tantalum powder S1-1h, S1-2h, S1-3h, S1-4h, S1-5h and S1-6h respectively; Analyze the oxygen content and the nitrogen content of above-mentioned tantalum powder, measure the apparent density and the BET specific area of tantalum powder, the result lists in the table 1.
Table 1
Data from table 1 find out that wherein the oxygen content of the tantalum powder of embodiment 1-5 (S1-5h) and embodiment 1-6 (S1-6h) is obviously much higher than the oxygen content of embodiment 1-1 (S1-1h), embodiment 1-2 (S1-2h), embodiment 1-3 (S1-3h), embodiment 1-4 (S1-4h).
The vacuum heat tantalum powder that uses the foregoing description 1-1 (S1-1h), embodiment 1-2 (S1-2h), embodiment 1-3 (S1-3h), embodiment 1-4 (S1-4h), embodiment 1-5 (S1-5h) and embodiment 1-6 (S1-6h) tantalum powder to obtain; Mix magnesium powder by tantalum grain weight amount 1.8%; Form mixed-powder respectively; Above-mentioned mixed-powder is respectively charged in the deoxidation heat treatment crucible lightly; The thickness of powder is about 58mm, the porosity that the tantalum powder in the crucible of deoxidation heat treatment at this moment has with vacuum heat tantalum powder is identical separately (be approximately vacuum heat tantalum powder porosity 100%).Pack in the deoxidation heat-treatment furnace according to method shown in Figure 2, under the argon pressure of 0.10～0.12MPa, be heated to 900 ℃ of insulations 3 hours, in argon gas, lower the temperature then; Carry out nitriding at 250 ℃, nitriding is evacuated to about 200 handkerchiefs with reaction vessel after accomplishing, and charges into the argon gas cool to room temperature then; Subsequently the tantalum powder is carried out passivation; After accomplishing passivation, the crucible that the tantalum powder after the passivation is housed is taken out in the deoxidation heat-treatment furnace, the tantalum powder is poured out in crucible.Above-mentioned tantalum powder is then dried with inorganic acid washing and washing, obtains the tantalum powder of S1-1d, S1-2d, S1-3d, S1-4d, S1-5d and S1-6d respectively.Analyze the oxygen content and the nitrogen content of tantalum powder, measure the apparent density and the BET specific area of tantalum powder, embodiment 1d result lists in the table 2.
Table 2
Result from table 1 and table 2 can find out; Increase along with vacuum heat stage tantalum powder filling thickness; The oxygen content of tantalum powder increases; After tantalum powder filling thickness surpassed 60mm, when under same deoxygenation conditions, carrying out deoxidation heat treatment, wherein the oxygen content of embodiment 1-5 (S1-5d) and embodiment 1-6 (S1-6d) gained tantalum powder after deoxidation heat treatment had surpassed desired value.
Measure the electrical property of the tantalum powder of S1-1d, S1-2d, S1-3d, S1-4d, S1-5d and S1-6d, the result lists in table 3.
Table 3
Can find out from the result of table 3, the tantalum powder after the deoxidation heat treatment, embodiment 1-1 (S1-1d), embodiment 1-2 (S1-2d), embodiment 1-3 (S1-3d), embodiment 1-4 (S1-4d) result are similar, and specific capacitance is higher, and leakage current is lower; And the specific capacitance of embodiment 1-5 (S1-5d) and embodiment 1-6 (S1-6d) tantalum powder is low, and leakage current is high, exceeds desired value.Reach a conclusion thus, when vacuum heat, the tantalum powder pack into the thickness of crucible be 60mm or following be the scope of the invention.
Embodiment 2-1, embodiment 2-2, embodiment 2-3, embodiment 2-4 and embodiment 2-5, the influence of the loading density/porosity of vacuum heat stage tantalum powder
Embodiment 2-1, embodiment 2-2, embodiment 2-3, embodiment 2-4 and embodiment 2-5 use and the same porosity of embodiment 1-1 use are 96.56% Ta powder, carry out the nodularization granulation, and obtaining apparent density is 1.08g/cm
3Granulation tantalum powder, granulation tantalum powder is packed in the vacuum heat crucible and is made that wherein tantalum powder thickness all is 51mm.Embodiment 2-1 pours the tantalum powder into the vacuum heat crucible lightly, and its porosity is 93.49%, is 96.8% of former tantalum powder porosity; Embodiment 2-2 be to pour the tantalum powder into the vacuum heat crucible, shake crucible lightly, the loading density of tantalum powder is 1.13g/cm
3, porosity is 93.19%, is 96.51% of former tantalum powder porosity; Embodiment 2-3 after pouring the tantalum powder into the vacuum heat crucible, vibrates 3 minutes, and loading density reaches 1.34g/cm
3, porosity is 91.93%, is 95.20% of former tantalum powder porosity; Embodiment 2-4 is with the water of the Ta powder adding 40% identical with embodiment 2-1, puts the vacuum heat crucible into and vibrates, and one deck water on the tantalum powder, occurs, drains top water, and the oven dry back forms the tantalum cake, and measuring its density is 2.17g/cm
3, its porosity is 86.73%, is 89.82% of former tantalum powder porosity; Embodiment 2-5 adds pack into behind 36% water vacuum heat crucible and compacting with Ta powder, and its apparent density is 2.52g/cm
3, its porosity is 84.8%, is 87.82% of former tantalum powder porosity; Above-mentioned tantalum powder carries out vacuum heat according to the identical condition of embodiment 1-1; Obtain S2-1h, S2-2h, S2-3h, S2-4h and S2-5h vacuum heat tantalum powder; Analyze the oxygen content and the nitrogen content of tantalum powder, measure the apparent density and the BET specific area of tantalum powder, the result lists in the table 4.
The above-mentioned S2-1h that obtains, S2-2h, S2-3h, S2-4h and S2-5h vacuum heat tantalum powder are carried out deoxidation heat treatment according to the condition identical with the S1-3h of embodiment 1-3, obtain S2-1d, S2-2d, S2-3d, S2-4d and S2-5d tantalum powder.The oxygen content of tantalum powder and nitrogen content, the result of apparent density and BET specific area lists in the table 5.
S2-1d after the above-mentioned deoxidation heat treatment, S2-2d, S2-3d, S2-4d and S2-5d tantalum powder are carried out electrical property detect, the result lists in the table 6.
Table 4
Table 5
Table 6
See from the oxygen content result of above-mentioned table 4, table 5 tantalum powder; In embodiment 2-1, embodiment 2-2, embodiment 2-3, embodiment 2-4 and embodiment 2-5, owing to increase gradually in the loading density of vacuum heat tantalum powder during the stage, the oxygen content of tantalum powder increases gradually after the vacuum heat; The BET specific area of tantalum powder reduces gradually; Apparent density increases gradually, and wherein embodiment 2-4 and the oxygen content of embodiment 2-5 tantalum powder after deoxidation heat treatment surpass desired value, do not belong to the scope of the invention.
Can find out from the tantalum powder electrical property result of table 6; The leakage current of tantalum anode is to increase along with the increase of its oxygen content; The leakage current of embodiment 2-1 (S2-1d), embodiment 2-2 (S2-2d), embodiment 2-3 (S2-3d) tantalum anode is low, and specific volume is high, belongs to the scope of the invention; And the specific volume of the tantalum anode of embodiment 2-4 (S2-4d) and embodiment 2-5 (S2-5d) is low, and leakage current exceeds desired value, does not belong to the scope of the invention.
In sum, tantalum powder filling porosity is more than 95% of former tantalum powder porosity when vacuum heat, and the oxygen content of tantalum powder is low, and the specific area loss is few, and the specific volume of electrical property is high, and leakage current is low, belongs to the scope of the invention; S2-4d and S2-5d tantalum powder filling hole crack rate when vacuum heat is below 90% of former tantalum powder porosity, and oxygen content is too high, and specific volume is low, and leakage current is high, and electrical property also is unacceptable, does not belong to the scope of the invention.
Comparative example 1
With the Ta powder of embodiment 1-1, according to the method for embodiment 2-4,, to put crucible into and vibrate the water of Ta powder adding 40%, the oven dry back forms the tantalum cake, and obtaining its density is 2.17g/cm
3, porosity is 86.73%, the thickness of tantalum powder in crucible is 75mm; Heat-treat condition according to embodiment 1-3 is identical is carried out vacuum heat; Carry out passivation after the cooling, the crucible that the tantalum powder after the passivation will be housed then takes out in vacuum heat treatment furnace, and the tantalum powder is poured out in crucible; The heating of tantalum powder is serious, and causes that the tantalum powder catches fire.The tantalum powder is described when vacuum heat, filling tantalum powder density is excessive in the crucible, and thickness is too big, causes that easily the tantalum powder catches fire.
Embodiment 3-1, embodiment 3-2, embodiment 3-3 and embodiment 3-4, deoxidation heat treatment tantalum powder charging thickness is to tantalum powder Effect on Performance
Use specific area to be 0.95m
2/ g, apparent density is 1.82g/cm
3(having 89.04% porosity); Oxygen content is the heat treated sodium reduction tantalum powder of 5600ppm, N content 90ppm; Mix magnesium powder by tantalum grain weight amount 1.6%; Form mixed-powder, above-mentioned mixed-powder is packed in the deoxidation heat treatment crucible, the charging thickness of powder is respectively 35mm, 45mm, 55mm and 75mm among embodiment 3-1, embodiment 3-2, embodiment 3-3 and the embodiment 3-4; Having 87.9%, 88.3%, 88.8% and 88.5% porosity respectively, is respectively 98.7%, 99.2%, 99.7% and 99.4% of former tantalum powder porosity.Condition according to embodiment 1-1 is carried out deoxidation heat treatment and subsequent treatment, obtains embodiment S3-1d, S3-2d, S3-3d and S3-4d tantalum powder, analyzes the oxygen content and the nitrogen content of tantalum powder, measures the apparent density and the BET specific area of tantalum powder, and the result lists in the table 7.Measure the electrical property of tantalum powder, the result lists in table 8.
Table 7
Table 8
Find out from the result of table 7 and table 8, in the deoxidation heat treatment of tantalum powder, tantalum powder charging thickness be oxygen content and the nitrogen content of S3-3d of S3-2d and 55mm of S3-1d, 45mm of 35mm all within desired value, and good electrical properties is arranged, within the scope of the present invention; Tantalum powder charging thickness is that the S3-4d oxygen content of 75mm is too high, and nitrogen content is lower, and electrical property is unacceptable, not within the scope of the present invention.
Embodiment 4-1, embodiment 4-2, embodiment 4-3 and embodiment 4-4, deoxidation heat treatment stages tantalum powder loading density is to tantalum powder Effect on Performance
The vacuum heat tantalum powder S1-3h (oxygen content 5880ppm, nitrogen content 100ppm, the BET specific area 0.98m that obtain with embodiment 1-3
2/ g, apparent density 1.83g/cm
3), being respectively charged into 4 deoxidation heat treatment crucibles, its thickness is 57mm, and tantalum powder loading density is respectively 1.83g/cm in embodiment 4-1, embodiment 4-2, embodiment 4-3 and embodiment 4-4
3, 1.95g/cm
3, 2.06g/cm
3And 2.65g/cm
3, its porosity is respectively 88.98%, 88.25%, 87.59% and 84.04%; It is respectively 100%, 99.18%, 98.44% and 94.48% of former tantalum powder porosity.Carry out deoxidation heat treatment and subsequent treatment according to embodiment 1-1 deoxygenation conditions, obtain embodiment S4-1d, S4-2d, S4-3d and S4-4d tantalum powder, analyze the oxygen content and the nitrogen content of tantalum powder, measure the apparent density and the BET specific area of tantalum powder, the result lists in the table 9.Measure the electrical property of tantalum powder, the result lists in table 10.
Table 9
Table 10
Find out from the result of table 9; In tantalum powder deoxidation heat treatment, tantalum powder loading density has very big influence to the performance of tantalum powder, and oxygen content increases and increases along with tantalum powder loading density; Nitrogen content increases and reduces along with tantalum powder loading density; The specific area of tantalum powder increases and reduces along with loading density, and the apparent density of tantalum powder increases and increases along with tantalum powder loading density, and the oxygen content of embodiment 4-4 surpasses desired value.Find out that from the electrical property of table 10 tantalum powder the leakage current of embodiment 4-4 exceeds desired value.See from above experimental result, when deoxidation heat treatment, should tantalum powder loading density be controlled at low scope, make that preferably the tantalum powder porosity in the deoxidation heat treatment crucible is more than 99% of former tantalum powder porosity.
In sum, according to the low and good electrical property of oxygen content of the tantalum powder of the inventive method preparation.
In above explanation, describe though be primarily aimed at the tantalum powder, can expect that like those skilled in the art the present invention also goes for other active metal powder, like niobium powder etc.
Claims (19)
1. the heat treatment method of a tantalum powder, this method comprise following the processing stage:
(1) the vacuum heat stage: with porosity is 80～98% the former tantalum powder crucible of packing into; Make in the crucible that the thickness of tantalum powder is below the 60mm and its porosity is more than 95% of former tantalum powder porosity; Place heating furnace under 900 ℃～1400 ℃ temperature, to heat in a vacuum then; Be cooled to room temperature subsequently and gained tantalum powder is carried out Passivation Treatment, obtain condensing the tantalum powder; With
(2) deoxidation heat treatment stages: cohesion tantalum powder and even the mixing of reducing agent that the stage (1) is obtained obtain mixed-powder; Said mixed-powder is packed in the crucible; Make in the crucible that the thickness of mixed-powder is below the 60mm and its porosity is more than 98% of former tantalum powder porosity, place heating furnace then and under 700 ℃～1100 ℃ temperature, heat in vacuum or inert atmosphere; Be cooled to room temperature subsequently and gained tantalum powder is carried out Passivation Treatment, thereby the tantalum powder that remaining reducing agent and dried and screened obtain being applicable to electrolytic capacitor is removed in pickling.
2. method according to claim 1 wherein in the said vacuum heat stage (1), makes that the porosity of tantalum powder is more than 98% of former tantalum powder porosity in the crucible.
3. method according to claim 1 wherein in the said vacuum heat stage (1), makes that the porosity of tantalum powder is 99%～100% of a former tantalum powder porosity in the crucible.
4. method according to claim 1, wherein in the said vacuum heat stage (1), the thickness of tantalum powder is 40～50mm in the crucible.
5. method according to claim 1, wherein in the said vacuum heat stage (1), be 30～90 minutes heat time heating time.
6. method according to claim 1 wherein in said deoxidation heat treatment stages (2), makes that the porosity of mixed-powder is 99%～100% of a former tantalum powder porosity in the crucible.
7. method according to claim 1, wherein in said deoxidation heat treatment stages (2), described reducing agent is selected from alkaline-earth metal, rare earth metal and hydride thereof.
8. method according to claim 7, wherein said reducing agent are the magnesium powder.
9. method according to claim 1, wherein in said deoxidation heat treatment stages (2), the thickness of mixed-powder is 40～60mm in the crucible.
10. method according to claim 1, wherein in said deoxidation heat treatment stages (2), be 1～6 hour heat time heating time.
11. the vacuum heat-treating method of a tantalum powder may further comprise the steps:
1) a kind of initial porosity being provided is the tantalum powder more than 80%;
2) said tantalum powder is packed in the vacuum heat crucible, make that tantalum powder thickness is below the 60mm in the crucible, and the porosity that is loaded into the tantalum powder in the crucible is more than 95% of tantalum powder initial porosity;
3) under vacuum, heat-treat in 900 ℃～1400 ℃ tantalum powder to the crucible of packing into;
4) cooling tantalum powder carries out Passivation Treatment to room temperature; With
5) the tantalum powder is taken out, thus dry and sieve and obtain heat treatment tantalum powder.
12. method according to claim 11, the wherein said porosity that is loaded into the tantalum powder in the crucible is more than 98% of tantalum powder initial porosity.
13. method according to claim 11, the wherein said porosity that is loaded into the tantalum powder in the crucible is 99%～100% of a tantalum powder initial porosity.
14. method according to claim 11, the thickness that wherein is loaded into the tantalum powder in the crucible is 40～50mm.
15. the deoxidation heat treatment method of a tantalum powder comprises step:
1) a kind of initial porosity being provided is the tantalum powder more than 80%;
2) the tantalum powder is mixed the formation mixed-powder with the reducing agent of 0.5%～3% tantalum grain weight amount, said reducing agent is selected from alkaline-earth metal, rare earth metal and hydride thereof;
3) said mixed-powder is packed in the heat treatment crucible, make that the porosity of the mixed-powder in the heat treatment crucible is more than 95% of tantalum powder initial porosity; And the thickness of the mixed-powder in the heat treatment crucible is below the 60mm;
4) under vacuum or inert atmosphere, heat-treat in 800 ℃～1100 ℃ tantalum powder to said adding reducing agent;
5) cooling tantalum powder carries out Passivation Treatment to room temperature; With
6) the tantalum powder is taken out, pickling, washing, drying are also sieved and are obtained the heat treated tantalum powder of deoxidation.
16. method according to claim 15 makes that wherein the porosity of the mixed-powder in the heat treatment crucible is more than 98% of tantalum powder initial porosity.
17. method according to claim 15 makes that wherein the porosity of the mixed-powder in the heat treatment crucible is 99%～100% of a tantalum powder initial porosity.
18. method according to claim 15, wherein said reducing agent are the magnesium powder.
19. method according to claim 15, wherein, the thickness that is loaded into the mixed-powder in the crucible is 40～60mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110039272 CN102120258B (en) | 2011-02-14 | 2011-02-14 | Thermal treatment method of tantalum powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110039272 CN102120258B (en) | 2011-02-14 | 2011-02-14 | Thermal treatment method of tantalum powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102120258A CN102120258A (en) | 2011-07-13 |
| CN102120258B true CN102120258B (en) | 2012-12-26 |
Family
ID=44248975
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201110039272 Active CN102120258B (en) | 2011-02-14 | 2011-02-14 | Thermal treatment method of tantalum powder |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102120258B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023109172A1 (en) | 2021-12-15 | 2023-06-22 | 宁夏东方钽业股份有限公司 | Tantalum powder production method and tantalum powder obtained thereby |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102382993B (en) * | 2011-10-09 | 2013-08-28 | 广东致远新材料有限公司 | Preparation method of target-grade ultrahigh-purity tantalum metal |
| CN102847934B (en) * | 2012-09-28 | 2014-04-09 | 泰克科技(苏州)有限公司 | Method for realizing heat treatment of capacitor tantalum powder through heat sources |
| CN103084568B (en) * | 2012-12-05 | 2014-12-03 | 江门富祥电子材料有限公司 | Device used for reducing tantalum powder by using magnesium to reduce oxygen content and provided with cooler and method for reducing tantalum powder by using magnesium to reduce oxygen content |
| CN103600086B (en) * | 2013-12-03 | 2016-05-04 | 宁夏东方钽业股份有限公司 | Powder used in metallurgy tantalum and/or niobium powder and preparation method thereof |
| EP3112059B1 (en) | 2014-02-27 | 2020-01-15 | Ningxia Orient Tantalum Industry Co., Ltd. | Preparation of high-purity tantalum powder |
| CN104493156B (en) * | 2014-12-12 | 2016-09-14 | 中国兵器科学研究院宁波分院 | The heat treatment method of nano-tantalum |
| CN105665731B (en) * | 2016-04-15 | 2017-10-27 | 陈尚军 | A kind of tantalum powder preparation method |
| RU2734851C2 (en) * | 2016-07-13 | 2020-10-23 | Нинся Ориэнт Танталум Индастри Ко.,Лтд. | Flaky tantalum powder and a method for production thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1197707A (en) * | 1997-04-29 | 1998-11-04 | 宁夏有色金属冶炼厂 | Production method of agglomerated tantalum powder |
| CN101139110A (en) * | 2007-08-25 | 2008-03-12 | 宁夏东方钽业股份有限公司 | Method for preparing low chemical valence niobium oxide or niobium powder |
| CN101348891A (en) * | 2008-08-29 | 2009-01-21 | 株洲硬质合金集团有限公司 | Tantalum powder controlled passivation magnesium processing deoxidization method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102004049039B4 (en) * | 2004-10-08 | 2009-05-07 | H.C. Starck Gmbh | Process for the preparation of finely divided valve metal powder |
-
2011
- 2011-02-14 CN CN 201110039272 patent/CN102120258B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1197707A (en) * | 1997-04-29 | 1998-11-04 | 宁夏有色金属冶炼厂 | Production method of agglomerated tantalum powder |
| CN101139110A (en) * | 2007-08-25 | 2008-03-12 | 宁夏东方钽业股份有限公司 | Method for preparing low chemical valence niobium oxide or niobium powder |
| CN101348891A (en) * | 2008-08-29 | 2009-01-21 | 株洲硬质合金集团有限公司 | Tantalum powder controlled passivation magnesium processing deoxidization method |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023109172A1 (en) | 2021-12-15 | 2023-06-22 | 宁夏东方钽业股份有限公司 | Tantalum powder production method and tantalum powder obtained thereby |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102120258A (en) | 2011-07-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102120258B (en) | Thermal treatment method of tantalum powder | |
| JP4215911B2 (en) | Niobium powder agglomerates | |
| EP2696406B1 (en) | Method for producing positive-electrode active material for lithium-ion battery | |
| AU2005293876B2 (en) | Method for the production of valve metal powders | |
| KR101129764B1 (en) | Process for Producing Niobium Suboxide | |
| EP1291100B2 (en) | Niobium or tantalum powder and method for production thereof | |
| CN105339512B (en) | The method of hypoxemia valve metal sintered body of the manufacture with high surface area | |
| JP2000508378A (en) | Method for reducing oxygen content in valve metal | |
| EP1236682A1 (en) | Silicon oxide powder and its manufacture | |
| US20050103638A1 (en) | Sintered bodies based on niobium suboxide | |
| BRPI0611216A2 (en) | process for heat treatment of metal dust and products made from it | |
| MX2010007621A (en) | Valve metal particles and the method for preparing the same. | |
| JP4828016B2 (en) | Tantalum powder manufacturing method, tantalum powder and tantalum electrolytic capacitor | |
| TW202325860A (en) | Method for producing tantalum powder for capacitor by reducing tantalum oxide with alkaline earth metal | |
| CN100535174C (en) | Nitrogen coping method for valve metal powder and nitrogen-containing tantalum powder and nitrogen-containing niobium powder acquired therefrom | |
| EP1891651A2 (en) | Capacitor | |
| CN103934452A (en) | Grouping method of tantalum powder with ultra-high specific volume and tantalum powder prepared through method | |
| WO2002004152A1 (en) | Metallic powder containing nitrogen, process for producing the same, and porous sinter and solid electrolytic capacitor both obtained from the same | |
| JPH01107089A (en) | High-purity internal lining for electric furnace | |
| WO2018010108A1 (en) | Flaky microcapsule and method for preparing same | |
| CN113560561B (en) | Spherical tantalum powder, preparation method and application thereof | |
| US20140076462A1 (en) | Method for passivating tantalum metal surface and apparatus thereof | |
| RU2649099C2 (en) | Method for producing valve metal powder | |
| JP2011249338A (en) | Method for sintering lithium-containing electrode material | |
| CN202072754U (en) | Tantalum metal surface passivation device provided with oxygen-containing gas refrigeration system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |