CN102157319A - Method for producing cathode component for flashlight - Google Patents

Abstract

The invention provides a new method for producing a cathode component for a flashlight. The method comprises the following steps of: carrying out calcining, ball milling and sieving on powdered raw materials, uniformly mixing the powdered raw materials with a thermoplastic or thermoset organic matter under the heating state, preparing the mixture into a green body having a certain shape by adopting the metal injection molding process, removing the organic matter in the green body through a chemical or heating method, obtaining a cathode basal body with certain porosity through high-temperature sintering, immersing an electron emission substance in a gap on the cathode basal body, and finally obtaining the cathode component for the flashlight through surface cleaning, washing and high-temperature treatment. The method has the advantage of preparing the cathode basal body material with considerably uniform density, controllable porosity and pore diameters, uniform pore diameters and narrow pore diameter distribution, simplifying the process for preparing the cathode component for the flashlight, reducing the production cost, and achieving volume production, low cost and considerably complex production shapes.

Description

A kind of photoflash lamp manufacture method of negative electrode part

Technical field

The present invention relates to the manufacture method of a kind of photoflash lamp with the negative electrode part.

Background technology

Cathode assembly is that photoflash lamp (typically comprises xenon flash lamp, helium photoflash lamp etc.) core component, negative electrode then is the heart of cathode assembly, be mainly used in emitting electrons, the matrix of negative electrode part is a loose structure, and the performance of cathode assembly is mainly determined by pore size, pore-size distribution situation, the kind of electron emission substrate and the dipping situation of electron emission substrate of cathode base.

Cathode assembly generally is made up of negative electrode part and support bar, and as shown in Figure 1,1 is the negative electrode part among the figure, and 2 is support bar, and 1 and 2 make up by welding manner.

Traditional photoflash lamp cathode assembly manufacture method mainly contains three kinds, and is as follows:

Method 1: tungsten filament is wrapped on the tungsten bar, in tungsten filament, floods electron emission substrate then, through obtaining cathode assembly after oven dry and the heat treated;

Method 2: material powder and electron emission substrate are mixed, after granulation, make material powder have certain fluidity, with moulding press material powder is pressed into the fairly simple green compact of shape, after degreasing is removed in the green compact because the organic substance that granulation is introduced, obtain the negative electrode part through sintering, at last negative electrode part and support bar welding assembly are obtained cathode assembly;

Method 3: make it have certain fluidity the material powder granulation, with moulding press tungsten powder is pressed into the fairly simple green compact of shape, remove in the green compact because the organic substance that granulation is introduced through degreasing, obtain having the tungsten piece of loose structure by follow-up sintering, at high temperature copper (or polymer) is dissolved and infiltrates in the tungsten piece then, obtain the designed shape of cathode base through machining, by chemistry and high-temperature process copper (or polymer) is removed again, in cathode base, flood electron emission substrate, through removing surface, obtain the negative electrode part after cleaning and the high-temperature process, if the negative electrode part shape is fairly simple, also can omit and ooze copper, machine work and remove process for copper, directly in the tungsten piece that sintering forms, flood electron emission substrate, after removing surface, obtain the negative electrode part after cleaning and the high-temperature process, at last negative electrode part and support bar welding assembly are obtained cathode assembly;

Adopt traditional handicraft to make photoflash lamp and have following problem with the negative electrode part:

(1) there are shortcomings such as the electronics emission is unstable, electron emissivity is weak, easily poisonings, not anti-electron bombard, life-span weak point in the negative electrode part ofmethod 1 preparation, in can only being applied to, low power photoflash lamp, can not be applied to high-power photoflash lamp;

(2) utilize the performance of the photoflash lamp negative electrode part ofmethod 2 preparations to be better thanmethod 1, but this method can only prepare the fairly simple photoflash lamp negative electrode part of shape, owing to added the portions of electronics emitting substance in the tungsten powder, these electron emission substrates can hinder tungsten powder and shrink in sintering process, make the cathode base mesopore bigger and inhomogeneous, the electron emission capability and the electronics launch stability of negative electrode part have been reduced, simultaneously, the existence of electron emission substrate in such negative electrode also can reduce the weld strength of negative electrode and support bar;

(3) cathode base of method 3 preparations has suitable pore size and distribution, can make the negative electrode part of shape more complicated, the performance of the photoflash lamp negative electrode part of this method preparation is better thanmethod 1 andmethod 2, but when adopting the negative electrode part of this method production shape more complicated, has the shortcoming that skeletal density is inhomogeneous, operation is long, efficient is low, cost is high, and the very difficult removal fully of the copper in the infiltration matrix, remaining copper can cause the poisoning of cathode, thereby influences the life-span of negative electrode part.

Summary of the invention

Utilize traditional handicraft to prepare photoflash lamp negative electrode part, have that electronics emission is unstable, electron emissivity is weak, easily poisonings, not anti-electron bombard, life-span are short, be difficult for welding, the complicated shape that can not be shaped, efficient is low and shortcoming such as cost height, the present invention aims to provide a kind of stable performance, strong, the anti-bombardment of strong, the anti-poisoning capability of electron emissivity, life-span length, easy welding, the complicated shape that can be shaped, efficient height and the low photoflash lamp negative electrode part preparation method of cost.

The present invention realizes by following steps:

(1) material powder is calcined, ball milling and the processing of sieving.

(2) under heated state, material powder and binding agent are mixed, binding agent generally is made up of one or more materials in the organic substances such as similar paraffin, polypropylene, polyethylene, polyformaldehyde, ethylene-vinyl acetate copolymer, dioctyl phthalate, stearic acid, zinc stearate, utilize injection forming equipment that mixture is prepared into the green compact that possess definite shape then, forming temperature is 120-200 ℃.

(3) pass through the method for chemical degreasing or hot degreasing with the organic matter removal in the green compact, as utilize organic solvent from green compact, to extract, utilize sour gas to make the method for binder decomposed or utilization heating make binder decomposed binding agent, obtain having the cathode base of certain porosity then by high temperature sintering in hydrogen, sintering temperature is 1400-2200 ℃, sintering time is 1-6h, the mean pore size 1-5 μ m of matrix is for porosity is 10-30%.

(4) electronic emitting material be impregnated in the cathode base.

(5) cathode material after will flooding carries out removing surface, cleaning and high-temperature process, promptly obtains photoflash lamp negative electrode part.

The invention has the advantages that:

(1) compares with traditional handicraft, the present invention can pass through the mixed proportion of kind, material powder and the binding agent of selection material powder, and the sintering process of matrix prepare density very evenly, pore size is controlled, the aperture is even, pore-size distribution is narrow cathode base material, thereby increased substantially cathode performance;

(2) compare with traditional handicraft, the present invention can disposable shaping photoflash lamp special-shaped cathode part, need not to ooze copper (or oozing polymer), machining and go copper technologies such as (or removing polymer), simplified the preparation technology of photoflash lamp with the negative electrode part, greatly improve stock utilization, saved expensive machine work cost, reduced manufacturing cost;

(3) compare with traditional handicraft, the invention provides one in enormous quantities, the method for negative electrode part that production shape at low cost is very complicated, improved the design freedom of cathode shape greatly.

Description of drawings

Fig. 1 is a photoflash lamp cathode assembly schematic diagram;

Fig. 2 is a green body shapes schematic diagram in the example 1;

Fig. 3 is a green body shapes schematic diagram in the example 2;

Fig. 4 is the pore-size distribution test result (testing equipment is the full-automatic mercury injection apparatus of Autopore IV series of Micromeritics Instrument Corp. U.S.A) of example 3 preparation cathode bases;

Fig. 5 is the electronic scanning photo in example 3 preparation cathode base cross sections, and the black region in the picture is equally distributed interconnected pore;

Embodiment

The present invention will be further described below with reference to example:

Example 1

The tungsten powder that with the 2500g Fisher particle size is 7 μ m is calcined 3h in 1500 ℃ of hydrogen furnaces, with ball mill ball milling 1h, cross 200 eye mesh screens then with standby.Under 150 ℃ temperature, tungsten powder and 48g paraffin, 20g polypropylene, 8g polyethylene and the 4g stearic acid of above-mentioned processing are mixed with double Z shaped blender, with injection moulding machine and mould mixture is prepared into shape green compact shown in the accompanyingdrawing 2, forming temperature is 160 ℃.With green compact as for soaking 4h in 40 ℃ the trichloroethylene to remove most paraffin of green compact and stearic acid, then with it as for slowly being warming up to 500 degrees centigrade and be incubated 2h in the hydrogen furnace, to remove remaining organic substance in the green compact, be warming up to 2000 ℃ of insulation 3h again and obtain cathode base, cathode base mesopore rate is about 20%, and average pore size is 2.6 μ m.Impregnation formulation is 411 aluminate electron emission substrate in above-mentioned cathode base, with the cotton remaining negative electrode salt in cathode base surface of removing of tungsten filament, and carry out ultrasonic waves for cleaning, at last with part as for calcining 30min in 1200 ℃ the hydrogen furnace, promptly obtain photoflash lamp negative electrode part.

Example 2

With the 2250g Fisher particle size is that the tungsten powder of 3 μ m and rhenium powder that the 250g Fisher particle size is 10 μ m mix, and calcines 5h in 1000 ℃ of hydrogen furnaces, with ball mill ball milling 2h, crosses 150 eye mesh screens then with standby.Under 190 ℃ temperature, material powder and 68g polyformaldehyde, 4.8g polyethylene, 4g ethylene-vinyl acetate copolymer, 1.6g paraffin and the 1.6g zinc stearate of above-mentioned processing are mixed with double Z shaped blender, with injection moulding machine and mould mixture is prepared into shape green compact shown in the accompanyingdrawing 2, forming temperature is 180 ℃.With green compact as for 4h in the mixed atmosphere of nitrogen and nitric acid, utilize the nitric acid branch to take off polyformaldehyde in the green compact, then green compact slowly are warming up to 700 degrees centigrade and be incubated 2.5h, to remove remaining organic substance in the green compact, be warming up to 1700 ℃ of insulation 4h again and obtain cathode base, cathode base mesopore rate is about 18%, and average pore size is 1.3 μ m.Impregnation formulation is 632 aluminate electron emission substrate in above-mentioned cathode base, with the cotton remaining negative electrode salt in cathode base surface of removing of tungsten filament, and carry out ultrasonic waves for cleaning, at last with part as for calcining 20min in 1000 ℃ the hydrogen furnace, promptly obtain photoflash lamp negative electrode part.

Example 3

With the 2250g Fisher particle size is that the tungsten powder of 5 μ m and rhenium powder, 125g Fisher particle size that the 125g Fisher particle size is 6 μ m are that the iridium powder of 6 μ m mixes, and calcines 1h in 1200 ℃ of hydrogen furnaces, with ball mill ball milling 4h, crosses 250 eye mesh screens then with standby.Under 160 ℃ temperature, tungsten powder and 52g paraffin, 16g polypropylene, 5.6g polyethylene, 4g ethylene-vinyl acetate copolymer and the 2.4g zinc stearate of the above-mentioned processing of 2500g are mixed with double Z shaped blender, with injection moulding machine and mould mixture is prepared into shape green compact shown in the accompanying drawing 3, forming temperature is 165 ℃.Green compact as for slowly being warming up to 800 degrees centigrade and be incubated 3h in the hydrogen furnace, to remove organic substance in the green compact, are warming up to 1900 ℃ of insulation 5h again and obtain cathode base, and cathode base mesopore rate is about 28%, and average pore size is 1.6 μ m.Dipping barium tungstate strontium calcium electron emission substrate in above-mentioned cathode base is removed the remaining negative electrode salt in cathode base surface with tungsten filament is cotton, and is carried out ultrasonic waves for cleaning, at last with part as for calcining 40min in 900 ℃ the hydrogen furnace, promptly obtain photoflash lamp negative electrode part.

Example 4

The tungsten powder that with Fisher particle size is 10 μ m is calcined 2h in 1400 ℃ of hydrogen furnaces, with ball mill ball milling 4h, cross 200 eye mesh screens then with standby.Under 140 ℃ temperature, tungsten powder and 60g polyethylene glycol, 18.4g polyformaldehyde, the 0.8g stearic acid of the above-mentioned processing of 2500g are mixed with double Z shaped blender, with injection moulding machine and mould mixture is prepared into shape green compact shown in the accompanying drawing 3, forming temperature is 180 ℃.With green compact as for soaking 3h in 75 ℃ the water to remove the polyethylene glycol in the green compact, then with green compact as for slowly being warming up to 700 degrees centigrade and be incubated 4h in the hydrogen furnace, to remove organic substance in the green compact, be warming up to 2300 ℃ of insulation 5h again and obtain cathode base, cathode base mesopore rate is about 24%, and average pore size is 2.9 μ m.Dipping BaO removes the remaining negative electrode salt in cathode base surface with tungsten filament is cotton, and carries out ultrasonic waves for cleaning as electron emission substrate in above-mentioned cathode base, at last with part as for calcining 10min in 600 ℃ the hydrogen furnace, promptly obtain photoflash lamp negative electrode part.

The above, only for preferred embodiment of the present invention, so can not limit scope of the invention process with this, i.e. the equivalence of doing according to the present patent application claim and description changes and modification, all should still belong in the scope that patent of the present invention contains.

Claims (5)

1. a photoflash lamp is characterized in that processing according to the following steps with the manufacture method of negative electrode part:

(1) material powder is calcined, ball milling and the processing of sieving;

(2) under heated state, material powder and binding agent are mixed, utilize metal injection molded technology mixture to be prepared into the green compact that possess definite shape then, binding agent passes through the method for chemistry, heating with the organic matter removal in the green compact, obtains having the cathode base of loose structure then by high temperature sintering;

(4) electronic emitting material be impregnated in the cathode base;

(5) cathode material after will flooding carries out removing surface, cleaning and oven dry and handles, and promptly obtains photoflash lamp negative electrode part.

2. according to the manufacture method of the described a kind of photoflash lamp of claim 1, it is characterized in that described binding agent is one or more materials compositions in paraffin or the organic substances such as polypropylene or polyethylene or polyformaldehyde or ethylene-vinyl acetate copolymer or dioctyl phthalate or stearic acid or zinc stearate with the negative electrode part.

3. according to the manufacture method of the described a kind of photoflash lamp of claim 2 with the negative electrode part, it is characterized in that material powder and binding agent are mixed under heated condition, mixing temperature is 120-200 ℃, utilize metal injection molded technology mixture to be prepared into the green compact that possess definite shape then, forming temperature is 120-200 ℃, by the chemistry or the heating method with the organic matter removal in the green compact, obtain having the cathode base of loose structure again by high temperature sintering, sintering temperature is 1400-2200 ℃.

4. according to the manufacture method of the described a kind of photoflash lamp of claim 3 with the negative electrode part, the mixed proportion that it is characterized in that kind, material powder and binding agent that will be by selecting material powder, and the sintering process of matrix can prepare, and pore size is controlled, the aperture even, the very narrow cathode base material of pore-size distribution, the porosity of cathode base is 10-30%, and mean pore size is 1-5 μ m.

5. according to the manufacture method of the described a kind of photoflash lamp of claim 1, it is characterized in that described photoflash lamp comprises xenon flash lamp, the helium photoflash lamp with the negative electrode part.

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