CN101256924A

CN101256924A - Method for assembling magnetron cathod and a melting contact metal for connecting filament and mo hat thereof

Info

Publication number: CN101256924A
Application number: CNA2008100822208A
Authority: CN
Inventors: 安义铉
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-02-27
Filing date: 2008-02-26
Publication date: 2008-09-03
Also published as: KR100825832B1

Abstract

The invention relates to a weld body of a cathode structural body and a cathode structural body, as well as manufacturing methods thereof. The invention provides a weld body manufactured by sintering a metal power containing ferrous powder and molybdenum powder, the manufacturing method of the weld body comprises the steps of mixing ferrous and molybdenum in a weight proportion of (25% to 55%) : (75% to 45%); moulding a green body by moudling process; placing the green body to a predetermined position of a molybdenum cap; and sintering in hydrogen atmosphere in a sintering furnace at a temperature of 1200 DEG C to 1500 DEG C. A top cap and an end cap attached with the manufactured weld body and a filament are assembled to a predetermined position for heating, the weld body is melted, such that the filament, the top cap and the end cap are totally fused via the melted weld body, thus forming a cathode structural body.

Description

The fusion body of cathode structure, cathode structure and their manufacture method

Technical field

The present invention relates to magnetron cathode structure manufacture method, be used for the filament of structure and the fusion body and the manufacture method (Method for assembling magnetron cathodeand a melting contact metal for connecting filament and Mo hat thereof) thereof of molybdenum cap welding.

Background technology

The cathode structure of magnetron has the such structure of sectional view shown in Figure 1.

Existing magnetron cathode structure shown in Figure 1 constitutes and comprises: spiral-shaped filament 1; The top end shield (end shield) 2 of supporting filament 1 upper end; The bottom end shield 3 of supporting filament 1 bottom; The hollow hole 3a of bottom end shield 3; Central support body 4, these central support body 4 supporting top end shields 2, and double as is to the lead-in wire of filament 1 energising predetermined power; Side support body 5, its supporting bottom end shield 3, and double as is to the lead-in wire of filament 1 energising predetermined power; And air-breathing metal film (getter) 6, the upper surface that it is weldingly fixed on top end shield 2 and bottom end shield 3 is used for adsorbed gas.

In the magnetron cathode structure that as above constitutes, above-mentioned filament 1 is formed by thorium-tungsten line etc. usually, and air-breathing metal film 6 is formed by zirconium or titanium, and in addition, top end shield 2, bottom end shield 3, central support body 4 and side support body 5 adopt refractory metals such as molybdenum or tungsten to form.

It is fixing that junction surface between junction surface between the both ends of filament 1 and top end shield 2, the bottom end shield 3, top end shield 2 and the central support body 4 and bottom end shield 3 and junction surface between the side support body 5 utilize the eutectic alloy welding material 7 of ruthenium and molybdenum to engage, thereby link to each other with electricity, mechanical system.

During this magnetron regular event, the central part temperature of filament reaches about 1750 ℃, and the junction between filament and the end shield reaches about 1000 ℃, so being used at least will be more than 1000 ℃ with the brazing material (brazing material) of filament and end shield joint, but, if melt temperature is too high, the energy consumption increase that then temperature of soldering oven rises required when soldering.

For this glower structure, in the past between filament and end shield coating mix ruthenium powder and molybdenum powder with 43: 57 weight ratio and metal dust stick with paste, put into after the soldering oven that remains under the atmosphere of hydrogen gas, apply power supply to heater coil, thereby glower structure is heated to about 2000 ℃, at this moment, metal dust is stuck with paste fusion, and filament and end shield are engaged.

But, in this existing glower structure, the melt temperature that ruthenium-molybdenum metal powder is stuck with paste is 1950 ℃～2000 ℃, very high, so glower structure need be heated to more than 2000 ℃, not only electric power consumption is big, and heater coil is subjected to very big thermal stress because of the circulation of carrying out on/off, therefore has the short defective of life-span of heater coil.

In order to solve existing defective, following grafting material has been proposed, this grafting material uses the lower metal dust paste that is made of nickel-ruthenium-molybdenum of melt temperature that filament and end shield are engaged.

This grafting material be with 30: 30: 40 weight ratio mixed Ni, ruthenium and molybdenum and carry out mixing and nickel-ruthenium-molybdenum stick with paste, its apparent specific gravity is 0.9～1.3, is used for the top and the bottom of filament 1 are bonded on

end shield

2,3.

This nickel-ruthenium-molybdenum is stuck with paste the junction that is applied to filament and end shield, put in the soldering oven that remains under the atmosphere of hydrogen gas, for with above-mentioned filament 1 and these two part bonding of end shield, the heater coil in soldering oven applies power supply, thereby this bonding part is heated.

Thus, nickel-ruthenium-molybdenum is stuck with paste fusion, forms soldering portion, and filament engages with end shield, at this moment, nickel-ruthenium-molybdenum paste by the good nickel powder of flammability in about 1500 ℃ of following fusions, with filament and end shield joint.

A kind of " end shield in the magnetron and the connecting ring of filament and electrically connected method " disclosed in Korean Patent 96-014521 number of on October 16th, 1996 registration; asked for protection and put down in writing " end shield in a kind of magnetron and the connecting ring of filament; it is characterized in that; the powders compression of ruthenium-molybdenum-nickel is sintered into the shape of ring (ring) (4; 7) " in the claim 1; put down in writing " end shield in the magnetron according to claim 1 and the connecting ring of filament; it is characterized in that; also be formed with lead-in wire (5) on any one in the above-mentioned ring (4; 7), the medial surface butt of this lead-in wire (5) and end shield (2; 6) " in the claim 2.

A kind of " scolder (SOLDERING MATERIALFOR FIXATION OF MAGNETRON END HAT IN MICROWAVEOVEN) that is used for fixing the magnetron end cap that uses in the microwave oven etc. " disclosed in Korean Patent 10-0207812 number of registration on 07 15th, 1999, at this, as the electrode support that is used for fixing the magnetron (Magnetron) that uses in the microwave oven is the scolder of top and the bottom end cap (END HAT) and filament with molybdenum (Mo) parts, used scolder 4, the iridium (Ir) that this scolder 4 utilizes at 5Wt%～70Wt%, the Ir-Mo-Ni or the Ir-Mo-Co mixed-powder that contain the cobalt (Co) of the nickel (Ni) of 5Wt%～70Wt% or 5Wt%～70Wt% in the molybdenum of 10Wt%～70Wt% (Mo) are made annular.At this, said top end shield or bottom end shield are same parts in top end cap and bottom end cap and other specifications, are formed by molybdenum, play supporting conductor effect to the filament supply capability filament time.

A kind of " scolder that is used for fixing the magnetron end cap that uses in the microwave oven etc. " disclosed in Korean Patent 10-0207811 number of registration on 07 15th, 1999, wherein, the scolder utilization Rh-Mo-Ni or the Rh-Mo-Co mixed-powder that contain the cobalt (Co) of the nickel (Ni) of 5Wt%～70Wt% or 5Wt%～70Wt% in the molybdenum (Mo) of the rhodium (Rh) of 5Wt%～70Wt%, 10Wt%～70Wt% made annular.

A kind of " scolder that is used for fixing the magnetron end cap that uses in the microwave oven etc. " disclosed in Korean Patent 10-0207813 number of registration on 07 15th, 1999, wherein, the scolder utilization Pd-Mo-Ni or the Pd-Mo-Co mixed-powder that contain the cobalt (Co) of the nickel (Ni) of 5Wt%～70Wt% or 5Wt%～70Wt% in the molybdenum (Mo) of the palladium (Pd) of 5Wt%～70Wt%, 10Wt%～70Wt% made annular.

But, develop the alloy that the scolder that uses uses rare metals such as molybdenum and palladium, nickel, cobalt, rhodium, iridium, ruthenium, platinum so far.Yet these metals belong to produces limited metal, is difficult to guarantee raw material, and the price height, so the unit price height of product, and competitiveness descends.

Also once attempted to mix molybdenum and iron uses in the past, but, the iron powder of easily oxidation in air and molybdenum powder are mixed when carrying out sintering, and because of adhesive (binder) and the iron that is used to mix, the gas that is adsorbed on the sintered body leaks into high vacuum (10 in magnetron moves ^-5Holder) in, there is the easy problem that worsens of performance of magnetron, so can't use.

Summary of the invention

The invention provides a kind of fusion body, molybdenum (Mo) parts that this fusion body is used for magnetron cathode structure that microwave oven is used i.e. top cap (top hat) and end cap (End Hat) engage with the filament electricity, are made of the alloy of iron and molybdenum.

The objective of the invention is to, a kind of fusion body that comprises molybdenum-ferroalloy is provided, wherein, substitute in the material of the fusion body (scolder) that in the past used rare metals such as mixing the palladium that uses, nickel, cobalt, rhodium, iridium, ruthenium with molybdenum, use iron (Fe).

The invention effect

Among the present invention, substitute rare precious metals such as existing platinum, palladium, cobalt, rhodium, iridium, ruthenium, use and failed the iron that uses in the past, therefore, solved prior art problems, buy raw material easily, can reduce price.And, can also make very big contribution to economizing on resources.

According to the present invention, can solve following existing issue: owing to utilize chopsticks or syringe to carry out and to be applied to the coating operation of welding position after ruthenium (Ru), molybdenum (Mo), nickel (Ni) mixing, therefore, the preparation work efficient of welding is low, the coating state is inhomogeneous, be difficult to obtain uniform welded condition, very large deviation appears in weld strength; When making top cap and end cap, melted material is made pasty state, be coated with one by one, thereby when producing product, be difficult to realize the production automation.

Using the sintered body of annular among the present invention is fusion body, therefore, handles easily, employed anchor clamps are simple, thereby need not preparation work, can efficiently carry out operation, and be distributed in the junction of cap and filament, welding property excellent, weld strength height with homogeneous thickness.

According to the present invention, can improve the quality of the middle magnetrons that use such as microwave oven, can reduce the manufacturing expense in the manufacturing process, thereby further have economic effect.

Description of drawings

Fig. 1 is the sectional view of existing magnetron cathode structure.

Fig. 2 is the sectional view of magnetron cathode structure of the present invention.

Embodiment

With reference to Fig. 2 the preferred embodiments of the present invention are described.Among the present invention the molybdenum powder that contains iron powder is carried out compression sintering, rather than " powder of ruthenium-molybdenum-nickel " of registration in Korean Patent 96-014521 number carried out compression sintering.In the magnetron usefulness operation of in making microwave oven etc., using of cathode structure, to be used to support negative electrode with filament and apply the molybdenum top cap of electric power and operation that end cap is electrically connected as shown in Figure 2, fusion body 24 is adhered in periphery upper end at the protuberance 25 that is formed at top cap 22, on the depressed part basal surface of end cap 26, adhere to fusion body 27, the top and bottom of filament 23 are connected between fusion body 24 and the fusion body 27 mutually, heat then, make

fusion body

24,27 fusions, thereby with filament 23 and top cap 22 and end cap 26 weldings.At this, the molybdenum powder that contains iron powder is meant and contains iron powder in the molybdenum powder, can also optionally contain other powder except that iron powder, metal dusts such as nickel, ruthenium, palladium, cobalt, rhodium, iridium, platinum for example, but must contain iron powder.

In this way with the cathode structure of filament assembling in, by going between 21 and during lead-in wire 28 power supplies, electric current flows through to top cap 22-filament 23-end cap 26, thus filament is heated, and emits hot electron, plays the magnetron cathode effect.

Fusion body the 24, the 27th of the present invention comprises the sintered body of ferromolybdenum, different with existing scolder (fusion body) in this, especially described fusion body is the sintered body that contains the molybdenum powder of iron powder, preferably in weight ratio, the iron that in molybdenum, mixes 25Wt%～55Wt%, carry out sintering, make sintered body.

Enumerate preferred embodiment, following explanation sintering fusion body of the present invention and manufacture method thereof.

At first, prepare after iron powder and the molybdenum powder, they are mixed with adhesive, put into then in the mould (mold), making external diameter with disc (disk) or open circle (doughnut) shape is that 3.5mm～4.5mm, internal diameter are that 3mm～4mm, thickness are the molded base substrate of 0.5mm～0.8mm, then, molded base substrate is put in the sintering furnace, being heated under the atmosphere of hydrogen gas about Celsius temperature 1200 degree～1500 degree, kept 24 hours, preferred about 40 hours, carry out sintering.

Thereby, can all be emitted from sintered body by the gas of adhesive and iron absorption.Sintering time is long more, and gas is emitted complete more, thus preferably long-time as far as possible sintering, but also can sintering about 10 hours.At this, adhesive uses the adhesive of the granulating agent, lubricant and other additives that are mixed with necessary amount.Sintered body carries out moulding by predetermined mould, and moulding adopts extrusion formings such as hydraulic press or automatic press to be predetermined shape (for example shapes such as disc, ring, four side plates).At this moment, the compression pressure during moulding remains on the intensity that can not hinder degree of treatment in the operation of back.

Organic bonds such as use vinyl adhere to one-time formed so molded base substrate on the main body of molybdenum cap.This organic bond uses the organic bond that gasifies when being heated to high temperature and disperse.At this moment, place molded base substrate in the precalculated position of top cap (the top cap is positioned at from the position of shown position upset), and on the precalculated position of end cap, place molded base substrate, in sintering furnace, carry out sintering.Sintering temperature is set at the temperature of carrying out sintering and top cap or end cap and contact site part welding degree when keeping molded base substrate, carries out sintering.Because fusing point is according to the mixed proportion of iron and molybdenum and different, so suitably set this temperature according to mixed proportion.This temperature is by calculating or rule of thumb finding out and use through test of many times.

If adhere to fusion body like this in advance, then be used for carrying out the manufacturing process that cathode structure connects, need not fusion body is inserted between filament and the cap one by one, after being attached with the assembling of the top cap of fusion body and end cap and filament in advance, heat, make their complete weldings, therefore, operation is very simple, and can implement reliably.

Molded base substrate can be in a vacuum or non-oxidizable atmosphere gas such as atmosphere of hydrogen gas in pre-burning at a lower temperature.If sharply heat when above-mentioned pre-burning, the possibility that then forms be full of cracks on the formed body becomes big, so sintering is very useful at low temperatures.

If above-mentioned pre-burning finishes, then at high temperature carry out main sintering, at this moment, main sintering is also identical with pre-burning to carry out in a vacuum or under the non-oxidizable atmosphere gas such as atmosphere of hydrogen gas, and sintering temperature also should be set at the temperature that can keep suitable intensity.

It is as follows that cathode structure connects operation.

Fusion body

24,27 is positioned at carries out sintering on top cap and the end cap, thereby with fusion body attached on top cap and the end cap, between two fusion bodies that are attached on top cap and the end cap, insert filament 23, be assembled into structure, in high-frequency induction furnace, apply the high heat that fusion body is melted fully, thus the welding as welding of filament and cap.The temperature of this moment should can be set suitable temperature according to the alloy ratio of sintered body about 1400 degree～2000 degree Celsius.As an example, apply high heat in 10 seconds, make their weldings.Filament is thorium oxide-tungsten (ThO ₂W) filament uses the filament that mixes 1% thorium of having an appointment.

Especially in the present invention, filament is put into the depressed part of the end cap 26 that is attached with fusion body 27 in advance, the top cap 22 that is attached with lead-in wire 21 and fusion body 24 is in advance inserted lead-in wire to the filament shaft portion, make in advance attached to after the end in contact on fusion body on the peripheral part of the protuberance 25 of top cap and the filament, in high-frequency induction furnace, apply high heat in 10 seconds, make the fusion body fusion, thereby with filament and the welding of molybdenum cap, so operation is very simple.

Claims

1, a kind of fusion body of cathode structure, this fusion body is used for filament being fused to top cap and the end cap that supports filament and apply electric power to filament at the magnetron cathode structure, it is characterized in that, this fusion body be the molybdenum powder that will contain iron powder be molded as carry out sintering after the shape such as disc and sintered body.

2, the fusion body of cathode structure according to claim 1, it is characterized in that, the following manufacturing of above-mentioned sintered body: with (25%～55%): the weight ratio of (75%～45%) is mixed iron and molybdenum obtains the iron molybdenum powder, this iron molybdenum powder is mixed with the adhesive that contains granulating agent and lubricant, the preparation mixed-powder, prepare molded base substrate with mixed-powder is molded, should put in the sintering furnace by molded base substrate, under atmosphere of hydrogen gas, with 1200 degree～1500 Celsius, spend and carry out sintering, thereby make sintered body.

3, a kind of manufacture method of fusion body of cathode structure, this method are used for being manufactured on the magnetron cathode structure for filament being fused to the fusion body that uses on top cap and the end cap, it is characterized in that described method comprises:

Mix molybdenum powder that contains iron powder and the adhesive that contains granulating agent and lubricant, make the step of fusion body base substrate by molding process; And

The fusion body base substrate that forms in the above-mentioned molding process put in the sintering furnace heat, make the step of sintered body.

4, a kind of manufacture method of fusion body of cathode structure, this method are used for being manufactured on the magnetron cathode structure for filament being fused to the fusion body that uses on top cap and the end cap, it is characterized in that described method comprises:

Mix the blend step of iron molybdenum powder and adhesive, in weight ratio, iron: molybdenum is (25%～55%): (75%～45%) in this iron molybdenum powder;

Utilize molding process the mixed-powder that obtains in the above-mentioned blend step to be made the molded step of fusion body base substrate;

The base substrate for preparing in the above-mentioned molded step is placed into the step on the precalculated position of molybdenum cap; And

Above-mentioned molybdenum cap and fusion body base substrate are put in the sintering furnace, under 1200 degree～1500 degree Celsius, made the step of sintered body.

5, a kind of manufacture method of cathode structure, this method is used to assemble the magnetron cathode structure, it is characterized in that, and described method comprises:

The step of mixing the molybdenum powder and the adhesive that contain iron powder;

Be molded into the molded step of fusion body base substrate by molding process;

Molded fusion body base substrate is placed into the step on the precalculated position of molybdenum cap;

Make in sintering furnace, under atmosphere of hydrogen gas, be heated to Celsius 1200 the degree～1500 the degree and the fusion body of sintering is attached to the step on the molybdenum cap; And

Heat after being assembled into assigned address being attached with the molybdenum cap of fusion body and filament in advance, the fusion body fusion, thereby with the step of the complete welding of above-mentioned filament.

6, a kind of cathode structure, this cathode structure is the magnetron cathode structure, it is characterized in that, this cathode structure comprises:

Be attached with the molybdenum top cap and the end cap of fusion body, this fusion body is a sintered body, it forms as follows: mix the molybdenum powder and the adhesive that contain iron powder, be molded as the molded base substrate of fusion body shape by molding process, molded base substrate is placed into the precalculated position of molybdenum cap, in sintering furnace, heat, form sintered body; And

Filament is assembled into this filament between the above-mentioned top cap that is attached with above-mentioned fusion body and the end cap and heats after the preposition, the fusion body fusion, thus filament is fused on above-mentioned top cap and the end cap.