CN100446898C - Method for sintering multielement composite electron emission material of rare earth tungsten - Google Patents
Method for sintering multielement composite electron emission material of rare earth tungsten Download PDFInfo
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- 238000005245 sintering Methods 0.000 title claims abstract description 79
- 238000000034 method Methods 0.000 title claims abstract description 22
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 title claims description 51
- 229910052721 tungsten Inorganic materials 0.000 title claims description 51
- 239000010937 tungsten Substances 0.000 title claims description 51
- 229910052761 rare earth metal Inorganic materials 0.000 title claims description 23
- 239000000463 material Substances 0.000 title claims description 19
- 150000002910 rare earth metals Chemical class 0.000 title claims description 19
- 239000002131 composite material Substances 0.000 title claims description 9
- 229910017583 La2O Inorganic materials 0.000 claims description 26
- 230000004927 fusion Effects 0.000 claims description 23
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims description 22
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims description 17
- 229910001404 rare earth metal oxide Inorganic materials 0.000 claims description 15
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 13
- 239000000314 lubricant Substances 0.000 claims description 13
- 229910052751 metal Inorganic materials 0.000 claims description 13
- 239000002184 metal Substances 0.000 claims description 13
- 229910052750 molybdenum Inorganic materials 0.000 claims description 13
- 239000011733 molybdenum Substances 0.000 claims description 13
- 239000000843 powder Substances 0.000 claims description 13
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 11
- 235000011187 glycerol Nutrition 0.000 claims description 11
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 239000000470 constituent Substances 0.000 description 15
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 11
- 239000001257 hydrogen Substances 0.000 description 11
- 229910052739 hydrogen Inorganic materials 0.000 description 11
- 238000003466 welding Methods 0.000 description 11
- 238000004458 analytical method Methods 0.000 description 10
- 238000002156 mixing Methods 0.000 description 10
- 239000000126 substance Substances 0.000 description 10
- WLTSUBTXQJEURO-UHFFFAOYSA-N thorium tungsten Chemical compound [W].[Th] WLTSUBTXQJEURO-UHFFFAOYSA-N 0.000 description 10
- 238000010792 warming Methods 0.000 description 10
- 238000005491 wire drawing Methods 0.000 description 10
- 229910052727 yttrium Inorganic materials 0.000 description 10
- 239000000203 mixture Substances 0.000 description 9
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- 238000009770 conventional sintering Methods 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 230000003068 static effect Effects 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000005204 segregation Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- IADRPEYPEFONML-UHFFFAOYSA-N [Ce].[W] Chemical compound [Ce].[W] IADRPEYPEFONML-UHFFFAOYSA-N 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 239000003870 refractory metal Substances 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical group [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 229910004369 ThO2 Inorganic materials 0.000 description 1
- 239000011149 active material Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 239000002932 luster Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002285 radioactive effect Effects 0.000 description 1
- 238000003904 radioactive pollution Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- ZCUFMDLYAMJYST-UHFFFAOYSA-N thorium dioxide Chemical compound O=[Th]=O ZCUFMDLYAMJYST-UHFFFAOYSA-N 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 238000004056 waste incineration Methods 0.000 description 1
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Abstract
A sintering method for the multi-element RE-W bar as an electron-emitting body with high finished product rate (more than 70%) features that the sintering current is properly decreased, and the density of sintered bar is controlled to 17.0-17.8 g/cu.cm.
Description
Technical field:
A kind of industrial sintering preparation method of multielement composite electron emission material of rare earth tungsten belongs to Rare Earth Doped Refractory Metal material technology field.
Background technology:
The tungsten electron emitter is the critical material in vacuum electronic components and parts, inert gas-shielded arc welding, Plasma Welding, cutting, spraying, melting and the particular electrical light source, and using at present more is that thorium tungsten material (contains ThO2) and cerium tungsten material (contain CeO2). Thorium tungsten material has naturally radioactive, all will bring harm to environmental and human health impacts in its production and use procedure; Cerium tungsten electron emitter has lower work function, but is difficult to carry large current capacity, thereby is of limited application, and can not substitute thorium tungsten electron emitter comprehensively.
In view of there is radioactive pollution in thorium tungsten electron emitter, from nineteen seventies, the novel electron emitter material is developed in succession to substitute thorium tungsten in countries in the world, wherein take electron emission material of rare earth tungsten as main, research finds that electron emission material of rare earth tungsten has good electron emission capability, the electron emitter of multiple compound rare-earth metal oxide particularly mixes, electron emission capability is excellent, can load by bearing great current, combination property is better than the thorium tungsten emitter, technology of preparing according to traditional tungsten electron emitter, should make the sintered blank bar densified during the incipient fusion sintering as far as possible, be beneficial to following process, therefore usually adopt large electric current sintering, the sintered blank rod density is controlled at 18.1-18.7g/cm3Yet the following process of sintered blank bar is very undesirable, yield rate is very low, only about 50%, yield rate 70% far below thorium tungsten electron emitter, thereby the product that sintered state is only arranged at present is applied to plasma-torch cutting and plasma waste incineration etc. emitter shape, state required undemanding field, and for more broad other field, higher production cost has hindered its application. Therefore be difficult to realize substituting thorium tungsten electron emitter comprehensively.
Summary of the invention:
The present invention changes tradition and improves sintering temperature, and to obtain high sintered density, the traditional habit of high processed finished products rate changes sintering curre, obtains the suitable sintered blank bar of density thereby suitably reduce sintering current, this base bar even tissue, and properties for follow is good.
The invention provides a kind of sintering method of multielement composite electron emission material of rare earth tungsten, it is characterized in that, may further comprise the steps:
1) by weight percentage, will contain La2O
3、Y
2O
3And CeO2The total content that every kind of rare earth oxide content is 0.4～1.4%, three kinds of rare earth oxides is 2～2.2%, and surplus is that the Rare-Earth Tungsten metal powder of tungsten adds lubricant, is pressed into the base bar of 13 * 13 * 450mm under 6-8MPa;
The above-mentioned base bar that 2) will suppress is put into molybdenum filament net stove and is carried out presintering, and sintering temperature is controlled at 1150-1350 ℃, is incubated 35-40 minute;
3) the base bar after the pre-burning is carried out the incipient fusion sintering, sintering current keeps 2 minutes speed by every increase 200A, increase to 2400A, be incubated after 2 minutes, increase electric current to 2500A, keep after 1 minute, continue to increase electric current to 2700A, kept 1 minute, then ultimate current is added to 2775-2825A, keep to obtain the sintered blank bar after 14-16 minute.
Hydrogen flowing quantity should be controlled at 1.0-1.4m during sintering3/ h. The com-pact density of sintering is at 17.0-17.8g/cm as stated above3, the base bar is silver gray, and metallic luster is arranged, the phenomenons such as free from flaw, bubbling and superfusion.
For tungsten, molybdenum and other refractory metals, for making the sintered blank bar have good processing characteristics, General Requirements sintered blank bar is DB, traditional sintering method generally adopts and keep carrying out in 30 minutes sintering under base bar 90% blowout current, for base bar 13 * 13 * 450mm that the tungsten industry is commonly used, its sintering current is 2900A-3100A, if adopt the method the multiplex composite rare-earth electron emitter is carried out sintering, though can improve the density of sintered blank bar, but can increase simultaneously segregation and the scaling loss of rare earth element, the rare earth element segregation will cause tissue odds even, directly affect following process, cause the finished product rate to be low to moderate about 50%, the scaling loss of rare earth element means the minimizing of the active material of low work function in the electron emitter, and the emitting performance of multielement composite electron emission material of rare earth tungsten descends when directly understanding. Therefore the base bar electron emission capability and the poor processability that adopt conventional sintering method sintering to go out.
For the parameter in above-mentioned the 3rd be only applicable to tungsten produce in 13 * 13 * 450mm compacting base bar of stock size, for the compacting base bar of other size, sintering current can determine according to the base bar sintering current density in the 3rd, namely , I whereina，S
aRespectively sintering current and the cross-sectional area of 13 * 13 * 450mm compacting base bar, Ib，S
bBe respectively the sintering current of institute's sintered blank bar and transversal and long-pending. Need to adjust by a small margin on this sintering current basis in general, finally to guarantee sintered blank rod density 17.0-17.8g/cm3In the scope.
This sintering method provided by the invention is different from the conventional sintering method, consider that the rare earth element segregation can directly cause material structure inhomogeneous and affect properties for follow, present technique changes conventional sintering and improves sintering current to pursue the technological thought of high com-pact density, adopt suitably reduce sintering current take the expendable material high density as cost to obtain uniform sintering structure technical thought, suitable reduction sintering current is controlled at 17.0-17.8g/cm with the sintered blank rod density3, the rare earth tungsten strip that obtains behind the sintering, even tissue, tungsten grain is equiax crystal, and the rare earth second-phase is evenly distributed on grain boundaries, and deformation can be coordinated by this low-density uniform formation in the following process process, and yield rate is more than 75%. And the rare earth composition scaling loss is little, and welding performance is good.
Description of drawings
Fig. 1. sintered blank bar tissue in the example 1, base bar tissue is similar with it in other examples.
Fig. 2. multiplex composite rare-earth tungsten electrode static characteristic of arc curve
The specific embodiment:
Comparative Examples
By weight percentage, with rare earth oxide content be: 0.44%La2O
3、1.32％Y
2O
3、
0.44％CeO
2Surplus is that the mixed metal powder of tungsten is 1: 1.5 lubricant by every 1Kg adding 5-7ml alcohol glycerine weight ratio, behind the batch mixing 1 hour, cross 80 mesh sieves, then under 6MPa, be pressed into the base bar of 13X13X450mm, when molybdenum filament net stove is preheated to 600-800 ℃, put into the base bar that suppresses, be warming up to 1200 ℃ of sintering 35 minutes, after pre-burning finishes, the base bar is put into the incipient fusion machine carry out the incipient fusion sintering, sintering current keeps 2 minutes speed by every increase 200A, increases to 2600A, be incubated after 2 minutes, increase electric current to 2700A, keep after 1 minute, continue to increase electric current to 2800A, kept 1 minute, then electric current is finally added to 2900A, keep to obtain the sintered blank bar after 30 minutes. Hydrogen flowing quantity should be controlled at 1.0m during sintering3/ h. The density of sintered blank bar is: 18.8g/cm3, chemical analysis sintered blank bar actual constituent is: 0.38% (weight) La2O
3, 1.18% (weight) Y2O
3, 0.35% (weight) CeO2Surplus is tungsten, proceeds B203, and B202, B201 swage and the finished electrode of Φ 1.6 is made in wire drawing, and the product integrated yield is 51%.
The B203 that mentions, B202, B201 are the common process process in the tungsten processing, are generally used for segmenting rotary swaging process, refer to the processing of swaging of adopting B-203, B-202, B-201 swager to carry out. B-203, B-202, B-201 are the unit type of swager.
Example 1:
By weight percentage, with rare earth oxide content be: 0.44%La2O
3、1.32％Y
2O
3、
0.44％CeO
2Surplus is that the mixed metal powder of tungsten is 1: 1.5 lubricant by every 1Kg adding 5-7ml alcohol glycerine weight ratio, behind the batch mixing 1 hour, cross 80 mesh sieves, then under 6MPa, be pressed into the base bar of 13X13X450mm, when molybdenum filament net stove is preheated to 600-800 ℃, put into the base bar that suppresses, be warming up to 1150 ℃ of sintering 35 minutes, after pre-burning finishes, the base bar is put into the incipient fusion machine carry out the incipient fusion sintering, sintering current keeps 2 minutes speed by every increase 200A, increases to 2400A, be incubated after 2 minutes, increase electric current to 2500A, keep after 1 minute, continue to increase electric current to 2700A, kept 1 minute, then electric current is finally added to 2825A, keep to obtain the sintered blank bar after 14 minutes. Hydrogen flowing quantity should be controlled at 1.0m during sintering3/ h. The density of sintered blank bar is: 17.1g/cm3, chemical analysis sintered blank bar actual constituent is: 0.49% (weight) La2O
3, 1.21% (weight) Y2O
3, 0.41% (weight) CeO2Surplus is tungsten, proceeds B203, and B202, B201 swage and the finished electrode of Φ 1.6 is made in wire drawing, and the product integrated yield is 75%.
Example 2:
By weight percentage, with rare earth oxide content be: 0.44%La2O
3、1.32％Y
2O
3、
0.44％CeO
2Surplus is that the mixed metal powder of tungsten is 1: 1.5 lubricant by every 1Kg adding 5-7ml alcohol glycerine weight ratio, behind the batch mixing 1 hour, cross 80 mesh sieves, then under 8MPa, be pressed into the base bar of 13X13X450mm, when molybdenum filament net stove is preheated to 600-800 ℃, put into the base bar that suppresses, be warming up to 1350 ℃ of sintering 45 minutes, after pre-burning finishes, the base bar is put into the incipient fusion machine carry out the incipient fusion sintering, sintering current keeps 2 minutes speed by every increase 200A, increases to 2400A, be incubated after 2 minutes, increase electric current to 2500A, keep after 1 minute, continue to increase electric current to 2700A, kept 1 minute, then electric current is finally added to 2875A, keep to obtain the sintered blank bar after 16 minutes. Hydrogen flowing quantity should be controlled at 1.4m during sintering3/ h. The density of sintered blank bar is: 17.8g/cm3, chemical analysis sintered blank bar actual constituent is: 0.45% (weight) La2O
3, 1.22% (weight) Y2O
3, 0.40% (weight) CeO2Surplus is tungsten, proceeds B203, and B202, B201 swage and the finished electrode of Φ 1.6 is made in wire drawing, and the product integrated yield is 79%.
Example 3:
By weight percentage, with rare earth oxide content be: 0.44%La2O
3、1.32％Y
2O
3、
0.44％CeO
2Surplus is that the mixed metal powder of tungsten is 1: 1.5 lubricant by every 1Kg adding 5-7ml alcohol glycerine weight ratio, the batch mixing material is after 1 hour, cross 80 mesh sieves, then under 7MPa, be pressed into the base bar of 13X13X450mm, when molybdenum filament net stove is preheated to 600-800 ℃, put into the base bar that suppresses, be warming up to 1250 ℃ of sintering 40 minutes, after pre-burning finishes, the base bar is put into the incipient fusion machine carry out the incipient fusion sintering, sintering current keeps 2 minutes speed by every increase 200A, increases to 2400A, be incubated after 2 minutes, increase electric current to 2500A, keep after 1 minute, continue to increase electric current to 2700A, kept 1 minute, then electric current is finally added to 2850A, keep to obtain the sintered blank bar after 15 minutes. Hydrogen flowing quantity should be controlled at 1.2m during sintering3/ h. The density of sintered blank bar is: 17.6g/cm3, chemical analysis sintered blank bar actual constituent is: 0.42% (weight) La2O
3, 1.23% (weight) Y2O
3, 0.40% (weight) CeO2Surplus is tungsten, proceeds B203, and B202, B201 swage and the finished electrode of Φ 1.6 is made in wire drawing, and the product integrated yield is 76%.
Example 4:
By weight percentage, with rare earth oxide content be: 0.73%La2O
3、0.73％Y
2O
3、
0.73％CeO
2Surplus is that the mixed metal powder of tungsten is 1: 1.5 lubricant by every 1Kg adding 5-7ml alcohol glycerine weight ratio, behind the batch mixing 1 hour, cross 80 mesh sieves, then under 6MPa, be pressed into the base bar of 13X13X450mm, when molybdenum filament net stove is preheated to 600-800 ℃, put into the base bar that suppresses, be warming up to 1150 ℃ of sintering 35 minutes, after pre-burning finishes, the base bar is put into the incipient fusion machine carry out the incipient fusion sintering, sintering current keeps 2 minutes speed by every increase 200A, increases to 2400A, be incubated after 2 minutes, increase electric current to 2500A, keep after 1 minute, continue to increase electric current to 2700A, kept 1 minute, then electric current is finally added to 2825A, keep to obtain the sintered blank bar after 14 minutes. Hydrogen flowing quantity should be controlled at 1.0m during sintering3/ h. The density of sintered blank bar is: 17.0g/cm3, chemical analysis sintered blank bar actual constituent is: 0.70% (weight) La2O
3, 0.72% (weight) Y2O
3, 0.69% (weight) CeO2Surplus is tungsten, proceeds B203, and B202, B201 swage and the finished electrode of Φ 1.6 is made in wire drawing, and the product integrated yield is 75%.
Example 5:
By weight percentage, with rare earth oxide content be: 0.73%La2O
3、0.73％Y
2O
3、
0.73％CeO
2Surplus is that the mixed metal powder of tungsten is 1: 1.5 lubricant by every 1Kg adding 5-7ml alcohol glycerine weight ratio, behind the batch mixing 1 hour, cross 80 mesh sieves, then under 8MPa, be pressed into the base bar of 13X13X450mm, when molybdenum filament net stove is preheated to 600-800 ℃, put into the base bar that suppresses, be warming up to 1350 ℃ of sintering 45 minutes, after pre-burning finishes, the base bar is put into the incipient fusion machine carry out the incipient fusion sintering, sintering current keeps 2 minutes speed by every increase 200A, increases to 2400A, be incubated after 2 minutes, increase electric current to 2500A, keep after 1 minute, continue to increase electric current to 2700A, kept 1 minute, then electric current is finally added to 2875A, keep to obtain the sintered blank bar after 16 minutes. Hydrogen flowing quantity should be controlled at 1.4m during sintering3/ h. The density of sintered blank bar is: 17.2g/cm3, chemical analysis sintered blank bar actual constituent is: 0.71% (weight) La2O
3, 0.72% (weight) Y2O
3, 0.68% (weight) CeO2Surplus is tungsten, proceeds B203, and B202, B201 swage and the finished electrode of Φ 1.6 is made in wire drawing, and the product integrated yield is 79%.
Example 6:
By weight percentage, with rare earth oxide content be: 0.73%La2O
3、0.73％Y
2O
3、
0.73％CeO
2Surplus is that the mixed metal powder of tungsten is 1: 1.5 lubricant by every 1Kg adding 5-7ml alcohol glycerine weight ratio, the batch mixing material is after 1 hour, cross 80 mesh sieves, then under 7MPa, be pressed into the base bar of 13X13X450mm, when molybdenum filament net stove is preheated to 600-800 ℃, put into the base bar that suppresses, be warming up to 1250 ℃ of sintering 40 minutes, after pre-burning finishes, the base bar is put into the incipient fusion machine carry out the incipient fusion sintering, sintering current keeps 2 minutes speed by every increase 200A, increases to 2400A, be incubated after 2 minutes, increase electric current to 2500A, keep after 1 minute, continue to increase electric current to 2700A, kept 1 minute, then electric current is finally added to 2850A, keep to obtain the sintered blank bar after 15 minutes. Hydrogen flowing quantity should be controlled at 1.2m during sintering3/ h. The density of sintered blank bar is: 17.6g/cm3, chemical analysis sintered blank bar actual constituent is: 0.70% (weight) La2O
3, 0.72% (weight) Y2O
3, 0.65% (weight) CeO2Surplus is tungsten, proceeds B203, and B202, B201 swage and the finished electrode of Φ 1.6 is made in wire drawing, and the product integrated yield is 78%.
Example 7:
By weight percentage, with rare earth oxide content be: 0.55%La2O
3、1.1％Y
2O
3、
0.55CeO
2Surplus is that the mixed metal powder of tungsten is 1: 1.5 lubricant by every 1Kg adding 5-7ml alcohol glycerine weight ratio, behind the batch mixing 1 hour, cross 80 mesh sieves, then under 6MPa, be pressed into the base bar of 13X13X450mm, when molybdenum filament net stove is preheated to 600-800 ℃, put into the base bar that suppresses, be warming up to 1150 ℃ of sintering 35 minutes, after pre-burning finishes, the base bar is put into the incipient fusion machine carry out the incipient fusion sintering, sintering current keeps 2 minutes speed by every increase 200A, increases to 2400A, be incubated after 2 minutes, increase electric current to 2500A, keep after 1 minute, continue to increase electric current to 2700A, kept 1 minute, then electric current is finally added to 2825A, keep to obtain the sintered blank bar after 14 minutes. Hydrogen flowing quantity should be controlled at 1.0m during sintering3/ h. The density of sintered blank bar is: 17.1g/cm3, chemical analysis sintered blank bar actual constituent is: 0.56% (weight) La2O
3, 0.99% (weight) Y2O
3, 0.53% (weight) CeO2Surplus is tungsten, proceeds B203, and B202, B201 swage and the finished electrode of Φ 1.6 is made in wire drawing, and the product integrated yield is 75%.
Example 8:
By weight percentage, with rare earth oxide content be: 0.55%La2O
3、1.1％Y
2O
3、
0.55％CeO
2Surplus is that the mixed metal powder of tungsten is 1: 1.5 lubricant by every 1Kg adding 5-7ml alcohol glycerine weight ratio, behind the batch mixing 1 hour, cross 80 mesh sieves, then under 8MPa, be pressed into the base bar of 13X13X450mm, when molybdenum filament net stove is preheated to 600-800 ℃, put into the base bar that suppresses, be warming up to 1350 ℃ of sintering 45 minutes, after pre-burning finishes, the base bar is put into the incipient fusion machine carry out the incipient fusion sintering, sintering current keeps 2 minutes speed by every increase 200A, increases to 2400A, be incubated after 2 minutes, increase electric current to 2500A, keep after 1 minute, continue to increase electric current to 2700A, kept 1 minute, then electric current is finally added to 2875A, keep to obtain the sintered blank bar after 16 minutes. Hydrogen flowing quantity should be controlled at 1.4m during sintering3/ h. The density of sintered blank bar is: 17.5g/cm3, chemical analysis sintered blank bar actual constituent is: 0.55% (weight) La2O
3, 1.02% (weight) Y2O
3, 0.54% (weight) CeO2Surplus is tungsten, proceeds B203, and B202, B201 swage and the finished electrode of Φ 1.6 is made in wire drawing, and the product integrated yield is 79%.
Example 9:
By weight percentage, with rare earth oxide content be: 0.55%La2O
3、1.1％Y
2O
3、
0.55％CeO
2Surplus is that the mixed metal powder of tungsten is 1: 1.5 lubricant by every 1Kg adding 5-7ml alcohol glycerine weight ratio, the batch mixing material is after 1 hour, cross 80 mesh sieves, then under 7MPa, be pressed into the base bar of 13X13X450mm, when molybdenum filament net stove is preheated to 600-800 ℃, put into the base bar that suppresses, be warming up to 1250 ℃ of sintering 40 minutes, after pre-burning finishes, the base bar is put into the incipient fusion machine carry out the incipient fusion sintering, sintering current keeps 2 minutes speed by every increase 200A, increases to 2400A, be incubated after 2 minutes, increase electric current to 2500A, keep after 1 minute, continue to increase electric current to 2700A, kept 1 minute, then electric current is finally added to 2850A, keep to obtain the sintered blank bar after 15 minutes. Hydrogen flowing quantity should be controlled at 1.2m during sintering3/ h. The density of sintered blank bar is: 17.4g/cm3, chemical analysis sintered blank bar actual constituent is: 0.53% (weight) La2O
3, 0.99% (weight) Y2O
3, 0.50% (weight) CeO2Surplus is tungsten, is proceeding B203, and B202, B201 swage and the finished electrode of Φ 1.6 is made in wire drawing, and the product integrated yield is 76%.
Because sintered blank bar rare earth composition scaling loss is serious in this visual contrast example, the processing rate variance, and sintered blank bar actual constituent and theoretical composition are more or less the same in the example, and the processed finished products rate all is higher than 75%, for comparing its welding performance difference, it is as follows that comparative selection example electrode and example 1, example 4, the electrode in the example 7 (because other electrodes and this electrode composition are more or less the same) carry out the welding performance test result:
1 electrode numbering:
Electrode numbering 1#: Comparative Examples 1 composition, actual constituent: 0.38% (weight) La2O
3, 1.18% (weight) Y2O
3, 0.35% (weight) CeO2Surplus is tungsten.
Electrode numbering 2#: example 1 composition, actual constituent: 0.49% (weight) La2O
3, 1.21% (weight) Y2O
3, 0.41% (weight) CeO2Surplus is tungsten.
Electrode numbering 3#: example 4 compositions, actual constituent: 0.70% (weight) La2O
3, 0.72% (weight) Y2O
3, 0.69% (weight) CeO2Surplus is tungsten.
Electrode numbering 4#, example 7 compositions, actual constituent: 0.56% (weight) La2O
3, 0.99% (weight) Y2O
3, 0.53% (weight) CeO2Surplus is tungsten.
2. striking performance:
(1) experiment condition:
The tungsten filament diameter is Φ 2.4mm, tip cone angle 45 degree, and electrode extension 8mm, arc duration 10s stops arc time 20s, arc length 3mm, number of repetition 30 times, argon flow amount 8L/min, straight polarity direct current, anode is the water-cooled red copper.
(2) experimental facilities
The thyristor control DC TIG welding connects power supply, model YC-300TSPVTA. Electronic stopclock, model JREREX.
(3) experimental result
When 30A, 80A, 150A welding current, each repeats striking 30 times respectively for 1#, 2#, 3#, 4# electrode, arcing initiation success rate 100%, striking function admirable.
3. anti-scorching performance:
(1) experiment condition
Electrode diameter is Φ 2.4mm, and used anode is the water-cooled red copper in the test, welding current 180A, and arc duration 20min, electrode extension 3mm, arc length 3mm, argon flow amount 8L/min, current type and polarity are straight polarity direct current.
(2) experimental facilities
The thyristor control DC TIG welding connects power supply, model YC-300TSPVTA. Slide measure, model 025, numbering 096583. Electronic balance AEL-200.
(3) result of the test
The test result of 1#, 2#, 3# and thorium tungsten electrode shown in table 3-2, can be known the scaling loss amount of these several multiplex composite rare-earth tungsten electrodes all less than thorium tungsten electrode respectively, illustrates that the novel rare-earth tungsten electrode that filters out has better anti-scorching performance.
Table 3-2 tungsten electrode anti-scorching performance
| Sample number into |
1# | 2# | 3# | 4# |
| Average scaling loss amount (mg) | 2.25 | 0.95 | 1.00 | 1.25 |
4 static characteristic of arc curves
(1) experiment condition
The tungsten filament diameter is Φ 1.6mm, tip cone angle 45 degree, and argon flow amount is 8L/min, electrode extension 3mm, arc length 3mm. Adopt the straight polarity direct current mode, tungsten filament is negative electrode, and anode is the water-cooled red copper.
(2) experimental facilities
The thyristor control DC TIG welding connects power supply, model YC-300TSPVTA. Digital multimeter, model Bestillingsnr.
(3) experimental technique and result
After the arcing, rapidly loop current being transferred to 20A, is 10A at electric current by from small to large order successively, 20A, 30A, 40A, 50A, 60A, 70A, 80A, 90A, 100A, 110A, 120A, 130A, 140A, 150A is during 160A, after arc burning is stable, measure corresponding steady-state current, magnitude of voltage, make respectively the static characteristic of arc curve (VA characteristic curve) of each electrode according to the voltage that records, current value, as shown in Figure 2. Can find out the 1# electrode owing to the composition scaling loss, its static characteristic of arc curve all is higher than other three kinds of electrodes, illustrates that the electron emission capability of this electrode is poor.
By top welding performance test result, can know that the product electron emission capability that adopts sintering method sintering provided by the present invention to go out is better than the product that adopts conventional sintering method sintering to go out.
Claims (1)
1, a kind of sintering method of multielement composite electron emission material of rare earth tungsten is characterized in that, may further comprise the steps:
1) by weight percentage, will contain La2O
3、Y
2O
3And CeO2Every kind of rare earth oxide content is 0.4～1.4%, the total content of three kinds of rare earth oxides is 2～2.2%, surplus is that the Rare-Earth Tungsten metal powder of tungsten adds lubricant, it is 1: 1.5 lubricant that mixed metal powder adds 5-7ml alcohol glycerine weight ratio by every 1Kg, is pressed into the base bar of 13 * 13 * 450mm under 6-8MPa;
The above-mentioned base bar that 2) will suppress is put into molybdenum filament net stove and is carried out presintering, and sintering temperature is controlled at 1150-1350 ℃, is incubated 35-40 minute;
3) the base bar after the pre-burning is carried out the incipient fusion sintering, sintering current keeps 2 minutes speed by every increase 200A, increase to 2400A, be incubated after 2 minutes, increase electric current to 2500A, keep after 1 minute, continue to increase electric current to 2700A, kept 1 minute, then ultimate current is added to 2775-2825A, keep to obtain the sintered blank bar after 14-16 minute.
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| CN106834780B (en) * | 2017-01-20 | 2018-09-25 | 赣州有色冶金研究所 | A kind of W-REO alloys and preparation method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1060709C (en) * | 1998-06-25 | 2001-01-17 | 北京工业大学 | Ternary compound rare-earth tungsten electrode material and its preparing process |
| US20050095163A1 (en) * | 2003-09-30 | 2005-05-05 | Hitachi Powdered Metals Co., Ltd. | Production method for sintered component made of stainless steel with high corrosion resistance |
| CN1234147C (en) * | 2004-06-28 | 2005-12-28 | 北京工业大学 | Discharge plasma method for preparing nano composite rare-earth tungsten electron emitting material |
| JP2006144064A (en) * | 2004-11-18 | 2006-06-08 | Neomax Co Ltd | Method for cleaning holder for sintering rare-earth sintering magnet, and method for manufacturing rare-earth sintering magnet |
| CN1274456C (en) * | 2004-09-30 | 2006-09-13 | 北京矿冶研究总院 | Preparation method of multicomponent composite rare earth-tungsten electrode material |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1060709C (en) * | 1998-06-25 | 2001-01-17 | 北京工业大学 | Ternary compound rare-earth tungsten electrode material and its preparing process |
| US20050095163A1 (en) * | 2003-09-30 | 2005-05-05 | Hitachi Powdered Metals Co., Ltd. | Production method for sintered component made of stainless steel with high corrosion resistance |
| CN1234147C (en) * | 2004-06-28 | 2005-12-28 | 北京工业大学 | Discharge plasma method for preparing nano composite rare-earth tungsten electron emitting material |
| CN1274456C (en) * | 2004-09-30 | 2006-09-13 | 北京矿冶研究总院 | Preparation method of multicomponent composite rare earth-tungsten electrode material |
| JP2006144064A (en) * | 2004-11-18 | 2006-06-08 | Neomax Co Ltd | Method for cleaning holder for sintering rare-earth sintering magnet, and method for manufacturing rare-earth sintering magnet |
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