CN101335166B - Cathode three-element alloy film and method for preparing film covered dipping diffusion cathode - Google Patents
Cathode three-element alloy film and method for preparing film covered dipping diffusion cathode Download PDFInfo
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- CN101335166B CN101335166B CN200710118004XA CN200710118004A CN101335166B CN 101335166 B CN101335166 B CN 101335166B CN 200710118004X A CN200710118004X A CN 200710118004XA CN 200710118004 A CN200710118004 A CN 200710118004A CN 101335166 B CN101335166 B CN 101335166B
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Abstract
The invention is a cathode ternary alloy film and a method for preparing coating-film dipped proliferation cathode, which relates to the technology of microwave electric-vacuum device manufacturing. The cathode ternary alloy film is a film of tungsten-rhenium-osmium ternary alloy. The method for preparing the coating-film dipped proliferation cathode comprises the following steps: A. before dipping an emitting material, a rhenium film is sputtered and deposited on the surface of cathode by adopting a surface sputtering method; an osmium-tungsten film is sputtered and deposited; next, the emitting material is dipped; by utilizing a high-temperature dipping process of the emitting material, the alloying of the cathode surface film is realized; B. after dipping the emitting material, the film of tungsten-rhenium-osmium ternary alloy is sputtered and deposited on the surface of the cathode by utilizing tungsten-rhenium-osmium ternary alloy target. The cathode prepared by the cathode ternary alloy film of the invention can enhance the density of current emitted by the cathode in a several-fold manner, and the emitting capacity of cathode is greatly improved; various specifications can be prepared in a comparatively easy way and batch production can be realized easily. The cathode of the invention can be applied to various electric-vacuum devices, and also can be used in to electronic tubes of TV and electronic microscopes.
Description
Technical field
The present invention relates to microwave electron tube manufacturing technology field, is that a kind of negative electrode is used the ternary alloy three-partalloy film and prepared the method that overlay film floods dispenser cathode.
Background technology
In microwave electron tube manufacturing technology field, overlay film dipping dispenser cathode (being called for short M type negative electrode) is a kind of negative electrode that generally adopts.It is characterized in that emissive material (barium aluminate salt) dipping is stored in spongy body of tungsten (cathode base) inside of porous, cathode surface deposits noble metal or alloy (Os, Os-Ru, Os-W, Ir, the W-Ir etc.) film that one deck reduces electron work functon.
Along with the microwave electron tube constantly develops to high power, high-frequency direction, require negative electrode can draw higher current density, yet, conventional overlay film dipping dispenser cathode, the 950 ℃ of direct current density that can effectively draw only are 3～5A/cm
2Can improve current density though improve the negative electrode working temperature, the problem of often following evaporation to increase.Cathode vaporation increases, and directly causes microwave device electrode insulation to descend, and spark phenomenon increases, and also can cause device and systemic breakdown when serious.
Up to now, for improving the emissivities of overlay film dipping dispenser cathode, developed several different methods.For example, U.S. Varian company has taked three kinds of method (R.E.Thomas, J.W.Gibson, G.A.Hass et al.IEEE Transactions on electron devices.1990, the 37 (3): 850-861): the one, at the film of cathode surface deposit multilayer heterogeneity; The 2nd, before the negative electrode overlay film, on tungsten basal body, add small amount of precious metals, to reduce the diffusion of noble metal to tungsten basal body; The 3rd, deposit noble metal film at cathode surface, to improve the uniformity of emission with preferred direction growth structure.China CAS Electronics Research Institute then adopts the method for covering (Os-W)/Re duplicature at cathode surface, and the direct current density that can make 950 ℃ on negative electrode is from 4.9A/cm
2, be increased to 5.6A/cm
2, increase rate be 14% (Yutao L, Honglai Zhang, Pukun Liu, Ming Zhang.A new dispensercathode with dual-layer.Appl.Surf.Sci.2005,251:126-129).
Above several method, though the cathode emission ability is increased, increase rate is all very limited.
Up to the present, still do not have a kind of comparatively simple method, the emission level of overlay film dipping dispenser cathode is significantly improved.
Summary of the invention
The objective of the invention is to,, propose a kind of negative electrode with the ternary alloy three-partalloy film and prepare the method that overlay film floods dispenser cathode and solve this problem at the lower problem of the horizontal increase rate of cathode emission that overlay film dipping dispenser cathode manufacturing technology field exists.
For achieving the above object, technical solution of the present invention is: find W-Re osmium (W-Re-Os) ternary alloy three-partalloy film first based on us, compare with existing alloy film, can form more strong and effective absorption to Ba and O, the special new method that proposes a kind of negative electrode with ternary alloy three-partalloy film and preparation overlay film dipping dispenser cathode.
A kind of negative electrode is the ternary alloy three-partalloy film that tungsten (W), rhenium (Re) and three kinds of elements of osmium (Os) are formed with the ternary alloy three-partalloy film.A kind of new method for preparing overlay film dipping dispenser cathode: comprise spongy body of tungsten preparation, negative electrode car system, cathode surface overlay film, soak operation such as salt.The invention is characterized in, in overlay film dipping dispenser cathode preparation process, the cathode surface overlay film adopts the ternary alloy three-partalloy film of being made up of tungsten (W), rhenium (Re) and three kinds of elements of osmium (Os), alloy film composition (weight ratio) is W45～65wt%, Re25～45wt%, Os10～30wt%, and thickness is 0.5～0.8 micron.Prepare this negative electrode and two kinds of methods arranged with the ternary alloy three-partalloy film:
Method one be successively sputtering sedimentation Re film and Os-W (40～65: 40～65wt%) films carry out high-temperature alloy (high temperature and the temperature retention time of alloying utilization dipping emissive material are finished) again; Method two is preparation W-Re osmium (W-Re-Os) ternary alloy three-partalloy target, at the direct sputter-deposited thin films of cathode surface.
Method one can change the composition of alloy film by adjusting thickness, the high-temperature alloy temperature and time of Re film and Os-W film.The thickness of ground floor Re film is at least 0.3 micron and maximum 0.6 micron.When high-temperature alloy was handled, Re was simultaneously to cathode base and the diffusion of surperficial W-Os film, because the diffusion velocity of Re is apparently higher than W and Os, the Re film is thin partially, diffusion finishes that the Re composition may be on the low side in the surface alloy film, and the Re film is thick partially, and the high-temperature alloy diffusion can make in the alloy film Re composition higher again.It is complicated that this method preparation technology shows slightly, but target is target commonly used, and configuration be the more important thing is that the film of high-temperature alloy combines with cathode base firmly, thereby had very strong anti-ion bombardment ability easily.
Method two adopts W-Re osmium (W-Re-Os) ternary alloy three-partalloy target to carry out sputtering sedimentation.This method thin film preparation process is simple, but without high-temperature alloy with the cathode base adhesion slightly a little less than, thin film stability is poor slightly.
Adopt a kind of negative electrode of the present invention to be with ternary alloy three-partalloy film and the obtained actual effect of method for preparing overlay film dipping dispenser cathode:
1, the emission of overlay film dipping dispenser cathode is significantly improved.The direct current density that 950 ℃ of invention negative electrodes can effectively be drawn is 13.0～14.8A/cm
2, draw direct current density 3～5A/cm with 950 ℃ on conventional negative electrode
2Compare, current density increases more than 2 times.The present invention has solved the problem that the cathode emission ability adopts prior art to be difficult to increase substantially preferably.
2, this method is applicable to the overlay film dipping dispenser cathode of all size, can satisfy the needs that negative electrode is produced in batches.
A kind of negative electrode of the present invention floods dispenser cathode with ternary alloy three-partalloy film and overlay film, because cathode emission current density is significantly improved, and can more easily be prepared into all size and be easy to realize batch process, therefore, in following long period of time, adopt the negative electrode of the inventive method preparation may progressively become main force's negative electrode that the high performance microwave pipe adopts.
Negative electrode of the present invention can be applicable to all kinds of microwave electron tubes such as klystron, travelling wave tube, gyrotron etc., also can use in the electron tube of television set and electron microscope.
Description of drawings
The schematic diagram of Fig. 1 negative electrode of the present invention;
Fig. 2 is for covering the Os-W bianry alloy film immersion dispenser cathode direct current emission j (A/cm of unit
2) logarithm and voltage U (V of unit) logarithmic chart;
Fig. 3 is the embodiment of the present invention one overlay film dipping dispenser cathode direct current emission j (A/cm of unit
2) logarithm and voltage U (V of unit) logarithmic chart;
Fig. 4 is the embodiment of the present invention two overlay films dipping dispenser cathode direct current emission j (A/cm of unit
2) logarithm and voltage U (V of unit) logarithmic chart.
Embodiment
As shown in Figure 1, indicate among the figure: negative electrode tungsten sponge matrix 11, molybdenum support tube 21, overlay film layer 31, emissive material 41, heater 51, alumina filled thing 61.
Negative electrode of the present invention is made up of negative electrode tungsten sponge matrix 11, molybdenum support tube 21, emitting surface overlay film layer 31, emissive material 41, heater 51 and alumina filled thing 61 etc.Wherein suppress by tungsten powder is adopted tungsten sponge matrix 11, sintering, soak copper, car system, go acquisition such as copper by common process.Tungsten sponge matrix 11 adopts molybdenum ruthenium solder to carry out high temperature brazing (2050 ℃ * 1～2 minute) with molybdenum support tube 21.Helix heater heater (there is the aluminum oxide coating layer of one deck electrophoresis on the tungsten-rhenium wire surface) 51 is positioned in the molybdenum tube, fills and sintering (1650 ℃ * 2～3 minutes) with the alumina insulation thing.Emissive material 41 is immersed in the spongy body of tungsten hole by conventional high temperature.
In said structure, surface coating layer 21 with special composition is features of the present invention, this overlay film layer is a W-Re-Os ternary alloy three-partalloy film, and alloy film element wt ratio is W 45～65wt%: Re 25～45wt%: Os 10～30wt%, the thickness of alloy film are 0.5～0.8 micron.Prepare this alloy film and can adopt in the following dual mode any one.
Execution mode one: before the dipping emissive material, adopt the Re film of Re target, obtain first tunic in cathode surface sputtering sedimentation 0.3～0.4 micron thickness; (55: 45wt%) target deposits 0.3～0.4 micron Os-W film, obtains second tunic to adopt Os-W afterwards; Next flood emissive material, utilize the high temperature dipping process of emissive material, make between the cathode surface double-layer films, fully diffusion between film and cathode base, realize the alloying of cathode surface rete.
Execution mode two: after the dipping emissive material, utilize composition than the ternary alloy three-partalloy target that is W45～65wt%: Re25～45wt%: Os10～30wt%, at the W-Re-Os ternary alloy three-partalloy film of cathode surface sputtering sedimentation 0.5～0.8 micron thickness.
It is generally acknowledged that in the existing overlay film dipping dispenser cathode, the dipping dispenser cathode that covers Os-W bianry alloy film has the highest emission level relatively.For cathode emission ability of the present invention is described, the elite dipping dispenser cathode that covers Os-W bianry alloy film of selecting compares.Negative electrode preparation and contrast experiment are as follows:
Example 1: cover Os-W bianry alloy film immersion dispenser cathode
Experiment condition: it is 24% spongy body of tungsten that cathode base 11 is selected cell size for use, 2.5 millimeters of matrix diameters; Cathode base and molybdenum support tube 21 adopt molybdenum ruthenium solder to carry out high temperature brazing (2050 ℃ * 1 minute); Heater 51 is packed in the molybdenum support tube 21, fill alumina filled thing 61, high temperature sintering 1650 ℃ * 3 minutes; Emissive material 41 is selected BaO for use: CaO: Al
2O
3Mol ratio is 6: 1: 2 aluminates (being called for short 612 aluminates), with guncotton 612 aluminate furnishing pasty states is coated in the cathode emission surface, carries out high temperature dipping (1600 ℃ * 30 seconds) in the hydrogen stove, repeats 4 times, until salt being soaked full cathode base 11; Remove the residual salt marsh of cathode surface with mechanical polishing and chemical cleaning method, target carries out reduction processing in 1250 ℃ * 5 minutes in the hydrogen stove; Adopt the ion bombardment lithographic technique to remove cathode surface machining deformation layer; Os-W bianry alloy film in cathode surface sputtering sedimentation 0.4～0.6 micron thickness.Prepare 3 negative electrodes altogether.
After installing and activating, negative electrode is measured emission in the water-cooled diode apparatus, adopts DC load, and cathode temperature is 950 ℃ (brightness temperatures).
3 negative electrodes to preparation have carried out the direct current emission measurement, and the result is: 950 ℃ of negative electrode direct current emission deviation point are 4.3A/cm
2, 4.6A/cm
2And 4.9A/cm
2, (deviation point is 4.9A/cm to Fig. 2 for typical negative electrode voltage-current characteristic test curve
2).Get the deviation point current average, the direct current emissivities that obtain covering Os-W film immersion dispenser cathode are 4.6A/cm
24.6A/cm
2Substantially represented the emission level of existing film cathode.
Example 2: adopt execution mode one preparation overlay film dipping dispenser cathode
Experiment condition: adopt the cathode base 11 identical with example 1; Cathode base 11 adopts molybdenum ruthenium solder to carry out high temperature brazing (2050 ℃ * 1 minute) with molybdenum support tube 21; Heater 51 is packed in the molybdenum support tube 21, fill alumina filled thing 61, high temperature sintering 1650 ℃ * 3 minutes; Adopt the ion bombardment lithographic technique to remove cathode surface machining deformation layer; The Re film of cathode surface elder generation sputtering sedimentation 0.3～0.4 micron thickness, the Os-W of sputtering sedimentation 0.3～0.4 micron thickness (55: 45wt%) film again; Emissive material 41 is selected 612 aluminates for use, with guncotton 612 aluminate furnishing pasty states are coated in the cathode emission surface, in the hydrogen stove, carry out high temperature dipping (1600 ℃ * 30 seconds), repeat 4 times, until salt being soaked full cathode base 11, this high temperature dipping process will make cathode surface obtain required W-Re-Os ternary alloy three-partalloy rete 31; Remove the residual salt marsh of cathode surface with mechanical polishing and chemical cleaning, target carries out reduction processing in 1250 ℃ * 5 minutes in the hydrogen stove.Prepare 3 negative electrodes altogether.
Negative electrode installation, activation are identical with example 1 with direct current transmission test condition.
To adopting 3 negative electrodes of the present invention of execution mode one preparation, carried out the direct current emission measurement, the result is: under 950 ℃, 3 negative electrode direct current emission deviation point are 13.8A/cm
2, 14.3A/cm
2And 14.8A/cm
2, (deviation point is 14.3A/cm to Fig. 3 for typical negative electrode voltage-current characteristic test curve
2).Get the deviation point current average, obtaining adopting the negative electrode direct current emissivities of the present invention of execution mode one is 14.3A/cm
2
Example 3 adopts execution mode two preparation overlay film dipping dispenser cathodes
Experiment condition: negative electrode preparation process and example 1 are basic identical, and difference is, the cathode surface sputtering sedimentation be the W-Re-Os ternary alloy three-partalloy film 31 of 0.5～0.6 micron thickness, the composition of film is W55wt%, Re25wt%, Os20wt%.Prepare 3 negative electrodes altogether.
Negative electrode installation, activation are identical with example 1 with direct current transmission test condition.
Adopt 3 invention negative electrodes of execution mode two preparations, its direct current emission measurement result is: under 950 ℃, negative electrode direct current emission deviation point is respectively 13.0A/cm
2, 13.2A/cm
2And 14.0A/cm
2, (deviation point is 14.3A/cm to Fig. 4 for 1 negative electrode volt-ampere characteristic wherein
2).Get the deviation point current average, obtaining thus adopting the negative electrode direct current emissivities of the present invention of execution mode two is 13.4A/cm
2
Comparative example and table 1 can clearly be seen that, compare with conventional overlay film dipping dispenser cathode (example 1 negative electrode), and negative electrode of the present invention adopts execution mode 1, and emissivities are 3.1 times of conventional negative electrode; Negative electrode of the present invention adopts execution mode 2, and emissivities are 2.9 times of conventional negative electrode.In a word, no matter which kind of execution mode negative electrode of the present invention adopts, and the emissivities of negative electrode all improve more than 1 times than the emissivities of conventional negative electrode.
The contrast of table 1 cathode emission situation
The present invention is not limited to above-mentioned concrete elaboration, can also visualize several variations within the scope of the invention.For example, alternating deposit Re film and Os-W film; Codeposition Re, Os, W film etc.In addition, when negative electrode adopts W-Re-Os ternary alloy three-partalloy film, also can change emissive material type (as the aluminate and the scandate of different mol ratio) or the like.
Claims (4)
1. a negative electrode ternary alloy three-partalloy film is characterized in that, is W-Re osmium ternary alloy three-partalloy film, and alloy film element wt ratio is: tungsten (W) 45～65wt%: rhenium (Re) 25～45wt%: osmium (Os) 10～30wt%, the thickness of alloy film is 0.5～0.8 micron.
2. negative electrode ternary alloy three-partalloy film as claimed in claim 1 is characterized in that, is used for the microwave electron tube, or the electron tube of television set or electron microscope.
3. negative electrode ternary alloy three-partalloy film as claimed in claim 1 is characterized in that, is used for the microwave electron tube, or uses in the electron tube of television set or the electron microscope.
4. a method of using ternary alloy three-partalloy film preparation overlay film to flood dispenser cathode with negative electrode as claimed in claim 1 comprises cathode surface overlay film, dipping emissive material operation; It is characterized in that two kinds of execution modes are arranged:
A: before the dipping emissive material, adopt the rhenium film of rhenium target, obtain first tunic in cathode surface sputtering sedimentation 0.3～0.4 micron thickness; Afterwards, adopt the osmium tungsten film of 0.3～0.4 micron of osmium tungsten 55:45wt% target deposition, obtain second tunic; Next flood emissive material, utilize the high temperature dipping process 1600 ℃ * 30 seconds of emissive material, make between the cathode surface double-layer films, fully diffusion between film and cathode base, realize the alloying of cathode surface rete;
B: after the dipping emissive material, utilize composition than being tungsten 45～65wt%: rhenium 25～45wt%: the ternary alloy three-partalloy target of osmium 10～30wt%, starve the ternary alloy three-partalloy film at the W-Re of cathode surface sputtering sedimentation 0.5～0.8 micron thickness.
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| CN101872707B (en) * | 2010-07-08 | 2013-06-05 | 中国电子科技集团公司第十二研究所 | Method for preparing dispenser cathode by using lithium magnesium silicate as shaping media |
| CN103050354A (en) * | 2011-10-17 | 2013-04-17 | 中国科学院电子学研究所 | Storage film-coating dipped barium-tungsten cathode and preparation method |
| CN103182508B (en) * | 2011-12-27 | 2014-12-10 | 北京有色金属研究总院 | Preparation method for alloy target material applied to M-typed cathode coating film with high current density |
| CN102945781B (en) * | 2012-10-17 | 2015-08-26 | 安徽华东光电技术研究所 | Dual-mode multi-beam electron gun for dual-mode traveling wave tube and control method thereof |
| CN113808892B (en) * | 2021-09-22 | 2023-10-20 | 中国科学院空天信息创新研究院 | Composite thermal subassembly and method of making the same |
| CN113936981B (en) * | 2021-09-29 | 2023-06-23 | 北京工业大学 | Preparation method of impregnated tungsten-rhenium-osmium ternary mixed base diffusion cathode |
| CN114203500A (en) * | 2021-11-29 | 2022-03-18 | 北京航空航天大学 | Method for producing emitter base assembly, emitter base assembly and electron gun |
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| CN1379703A (en) * | 1999-10-20 | 2002-11-13 | 陶氏化学公司 | Catalytic powder and electrode made therewith |
| US20060153539A1 (en) * | 2002-09-10 | 2006-07-13 | Sanyo Electric Co., Ltd. | Motion image recording device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1379703A (en) * | 1999-10-20 | 2002-11-13 | 陶氏化学公司 | Catalytic powder and electrode made therewith |
| US20060153539A1 (en) * | 2002-09-10 | 2006-07-13 | Sanyo Electric Co., Ltd. | Motion image recording device |
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