阅读说明：本技术 一种钍钨热丝引脚钎焊方法 (Thorium-tungsten hot wire pin brazing method ) 是由 王鹏康 沈旭东 赵艳珩 刘鲁伟 于 2020-06-15 设计创作，主要内容包括：本发明提供了一种钍钨热丝,包括热丝,所述热丝绕制成单螺旋形状,单螺旋热丝可以进一步加工成双螺旋形或盘香形,所述热丝的两端设有热丝引脚,两端所述热丝引脚引线的一端深入到热丝螺旋线4～8圈的位置上,在所述热丝引脚与所述热丝的连接处通过钨钴焊料粉进行焊接,本发明还提供了一种钍钨热丝引脚钎焊方法,包括a：钨钴焊料粉的配置；b：热丝引脚及热丝净化处理；c：热丝引脚与热丝组装；d：钨钴焊料粉的涂覆；e：氢炉焊接；f：钎焊质量检测；本发明提供的钍钨热丝引脚钎焊方法具有工艺重复性和一致性高,可操作性强和可靠性高的的特点,通过该方法制备的热丝,可提高热丝的抗震能力,同时可缩短电子源启动时间,提高加热效率。(The invention provides a thorium tungsten hot wire, which comprises a hot wire, wherein the hot wire is wound into a single spiral shape, the single spiral hot wire can be further processed into a double spiral shape or a incense coil shape, hot wire pins are arranged at two ends of the hot wire, one ends of leads of the hot wire pins at the two ends penetrate into the position of 4-8 circles of the hot wire spiral line, and tungsten-cobalt solder powder is used for welding at the connecting part of the hot wire pins and the hot wire, and the invention also provides a thorium tungsten hot wire pin brazing method which comprises the following steps: preparing tungsten cobalt solder powder; b: purifying the hot wire pins and the hot wires; c: assembling the hot wire pin with the hot wire; d: coating tungsten cobalt solder powder; e: welding a hydrogen furnace; f: detecting the brazing quality; the thorium tungsten hot wire pin brazing method provided by the invention has the characteristics of high process repeatability and consistency, strong operability and high reliability, and the hot wire prepared by the method can improve the shock resistance of the hot wire, shorten the starting time of an electron source and improve the heating efficiency.)

1. A thorium tungsten hot wire, comprising a hot wire (1), characterized in that: the hot wire (1) is wound into a single spiral shape, the single spiral hot wire can be further processed into a double spiral shape or a coiled incense shape, hot wire pins (2) are arranged at two ends of the hot wire (1), one end of a lead of each hot wire pin (2) penetrates into the position of 4-8 circles of the spiral line of the hot wire (1), and the joint of each hot wire pin (2) and the corresponding hot wire (1) is welded through tungsten-cobalt solder powder (3).

2. The thorium tungsten hot wire of claim 1, wherein: the preparation method of the tungsten-cobalt solder powder (3) comprises the following steps: according to the actual using amount, the tungsten powder and the cobalt powder are respectively weighed according to the weight ratio of 2:7, the tungsten powder and the cobalt powder are placed in an agate mortar, a pestle is used for stirring the mixture for 50-60 minutes until the tungsten powder and the cobalt powder are fully mixed, and finally the mixed powder is placed in a weighing bottle for later use.

3. A thorium tungsten hot wire pin brazing method is characterized in that: the method comprises the following steps:

a: preparing tungsten cobalt solder powder: according to the actual using amount, weighing tungsten powder and cobalt powder according to the weight ratio of 2:7, placing the tungsten powder and the cobalt powder in an agate mortar, stirring the mixture with a pestle for 50-60 minutes until the tungsten powder and the cobalt powder are fully mixed, and finally placing the prepared tungsten-cobalt solder powder in a weighing bottle for later use;

b: and (3) hot wire pins and hot wire purification treatment: soaking the cut hot wire pins (2) and the wound hot wire (1) by using an organic solvent trichloroethylene or acetone for deoiling, and then performing purification treatment in a hydrogen atmosphere, wherein the purification treatment process is specified to be that the temperature is 900-1100 ℃, and the temperature is kept for 3-10 minutes;

c: assembling the hot wire pin with the hot wire: c, arranging the leads of the hot wire pins (2) purified in the step b at two ends of the hot wire (1), wherein one end of each lead extends into 4-8 circles of the spiral line of the hot wire (1) or one end of each lead extends into 5-10 mm of the spiral line of the hot wire (1), and the leads and the hot wire (1) can be pre-fixed in a laser welding mode at proper time;

d: coating of tungsten cobalt solder powder: b, preparing a welding flux for coating by adding 15-30 mL of nitrocotton solution into the tungsten-cobalt welding flux powder (3) prepared in the step a according to the proportion that the nitrocotton solution is added into 100g of the tungsten-cobalt welding flux powder, fully stirring and blending the welding flux into a paste, coating the tungsten-cobalt welding flux brush (3) at the joint of the hot wire pin (2) and the hot wire (1) assembled in the step c by using a writing brush, and baking in an oven after coating is finished;

e: welding a hydrogen furnace: d, placing the assembly coated with the solder in the step d into a welding furnace in hydrogen atmosphere for brazing;

f: and (3) brazing quality detection: the brazing quality is observed under a microscope, the solder flows uniformly, and the gap between the hot wire pin (2) and the hot wire (1) is fully filled with the solder, so that the brazing of the hot wire (1) and the hot wire pin (2) is completed.

4. The method of brazing thorium tungsten hot wire pins of claim 3, wherein: the melting temperature of the tungsten-cobalt solder powder (3) in the step a is 1450-1500 ℃.

5. The method of brazing thorium tungsten hot wire pins of claim 3, wherein: in the step b, the hot wire (1) can be wound into a single-spiral shape, the single-spiral hot wire can be further processed into a double-spiral shape or a coil shape, and thorium tungsten alloy wires are selected as materials of the hot wire (1).

6. The method of brazing thorium tungsten hot wire pins of claim 3, wherein: and c, selecting one of tungsten, molybdenum, tungsten-rhenium, molybdenum-rhenium and the like as the lead of the hot wire pin (2) in the step c.

7. The method of brazing thorium tungsten hot wire pins of claim 3, wherein: and d, baking in the baking oven in the step d at the temperature of 80-100 ℃ for 10-20 minutes.

8. The method of brazing thorium tungsten hot wire pins of claim 3, wherein: the brazing temperature in the step e is 1450-1500 ℃, and the brazing time is 1-2 minutes.

Technical Field

The invention relates to the technical field of hot wire pin brazing processing, in particular to a thorium tungsten hot wire pin brazing method.

Background

In vacuum devices, a hot cathode is generally used as an electron source, and the hot cathode can be classified into a direct heating type and an indirect heating type. In either case, a core component, the "hot wire", is required, and the structure and performance of the hot wire, which serves as the heat source for the hot cathode, are directly related to the performance, lifetime and reliability of the device. Currently, the institute studies an electron source applied to an ion thruster, using thorium tungsten wire as a direct-heating cathode. The device requires that the shock resistance and the impact resistance are very high in level, the thorium tungsten wire hot wire pin is fixed in a large-current spot welding mode according to the traditional thorium tungsten wire hot wire pin, and breakage of the thorium tungsten wire at the position of the hot wire pin often occurs in the using process, so that the device is scrapped. Through problem analysis, the reason lies in adopting the mode of heavy current spot welding to fix, appears spot welding position oxidation serious, the defect that contact resistance is big, and the device during operation causes thorium tungsten filament hot wire pin position high temperature, and the problem that shock resistance descends appears.

Disclosure of Invention

The invention provides a thorium tungsten hot wire pin brazing method which is used for solving the technical problems in the background technology.

In order to solve the technical problems, the invention adopts the technical scheme that: the utility model provides a thorium tungsten heater, includes the heater, the heater is coiled into single spiral shape, and single spiral heater can further be processed into two heliciform or incense coils shape, the both ends of heater are equipped with the heater pin, both ends the one end of heater pin lead wire is deepened to the position of 4 ~ 8 rings of heater helix the heater pin with the junction of heater welds through tungsten cobalt solder powder.

Further, the preparation method of the tungsten cobalt solder powder comprises the following steps: according to the actual dosage, weighing tungsten powder and cobalt powder according to the weight ratio of 2:7, placing the tungsten powder and the cobalt powder into an agate mortar, stirring the mixture with a pestle for 50-60 minutes until the tungsten powder and the cobalt powder are fully mixed, and finally placing the mixed powder into a weighing bottle for later use

The invention also provides a thorium tungsten hot wire pin brazing method, which comprises the following steps:

a: preparing tungsten cobalt solder powder: according to the actual using amount, weighing tungsten powder and cobalt powder according to the weight ratio of 2:7, placing the tungsten powder and the cobalt powder in an agate mortar, stirring the mixture with a pestle for 50-60 minutes until the tungsten powder and the cobalt powder are fully mixed, and finally placing the prepared tungsten-cobalt solder powder in a weighing bottle for later use;

b: and (3) hot wire pins and hot wire purification treatment: soaking the cut hot wire pins and the wound hot wire by using an organic solvent trichloroethylene or acetone for deoiling, and purifying in a hydrogen atmosphere after deoiling, wherein the purification treatment process is specified to keep the temperature within the range of 900-1100 ℃ for 3-10 minutes;

c: assembling the hot wire pin with the hot wire: c, arranging the hot wire pin leads purified in the step b at two ends of the hot wire, wherein one end of each lead is inserted into 4-8 circles of the hot wire spiral line or one end of each lead is inserted into a position 5-10 mm of the hot wire spiral line, and the leads and the hot wire can be pre-fixed in a laser welding mode at proper time;

d: coating of tungsten cobalt solder powder: b, adding 15-30 mL of nitrocotton solution into the tungsten-cobalt solder powder prepared in the step a according to the weight of 100g to prepare a coating solder, fully stirring and blending the solder into a paste, brushing the tungsten-cobalt solder on the joint of the hot wire pin and the hot wire assembled in the step c by using a writing brush, and baking in an oven after coating;

e: welding a hydrogen furnace: d, placing the assembly coated with the solder in the step d into a welding furnace in hydrogen atmosphere for brazing;

f: and (3) brazing quality detection: and (4) observing the brazing quality under a microscope, wherein the solder flows uniformly, and the gap between the hot wire pin and the hot wire is fully filled with the solder, so that the brazing of the thorium tungsten hot wire and the hot wire pin is completed.

Further, the melting temperature of the tungsten cobalt solder powder in the step a is 1450-1500 ℃.

Further, in the step b, the hot wire can be wound into a single spiral shape, the single-spiral hot wire can be further processed into a double-spiral shape or a coil shape, and the material of the hot wire is thorium tungsten alloy wire.

Furthermore, in the step c, the lead of the hot wire pin is made of one of tungsten, molybdenum, tungsten-rhenium, molybdenum-rhenium and the like.

Further, in the step d, the baking temperature in the baking oven is 80-100 ℃, and the baking time is 10-20 minutes.

Furthermore, the brazing temperature in the step e is 1450-1500 ℃, and the brazing time is 1-2 minutes.

Compared with the prior art, the invention has the beneficial effects that:

the thorium tungsten hot wire pin brazing method provided by the invention has the characteristics of high process repeatability and consistency, strong operability and high reliability, and the hot wire prepared by the method can improve the shock resistance of the hot wire, shorten the starting time of an electron source and improve the heating efficiency.

Drawings

Fig. 1 is a schematic structural view of a hot wire pin and a hot wire assembly after the welding of the present invention.

In the figure: 1-heating wire; 2-hot wire pins; 3-tungsten cobalt solder powder.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

The invention provides a thorium tungsten hot wire which comprises a hot wire 1, wherein the hot wire 1 is wound into a single spiral shape, the single spiral hot wire can be further processed into a double spiral shape or a incense coil shape, hot wire pins 2 are arranged at two ends of the hot wire 1, one ends of leads of the hot wire pins 2 at two ends are inserted into the position of 4-8 circles of a hot wire 1 spiral line, and tungsten-cobalt solder powder 3 is welded at the connecting part of the hot wire pins 2 and the hot wire 1.

The preparation method of the tungsten-cobalt solder powder 3 comprises the following steps: according to the actual dosage, weighing tungsten powder and cobalt powder according to the weight ratio of 2:7, placing the tungsten powder and the cobalt powder into an agate mortar, stirring the mixture with a pestle for 50-60 minutes until the tungsten powder and the cobalt powder are fully mixed, and finally placing the mixed powder into a weighing bottle for later use

The invention also provides a thorium tungsten hot wire pin brazing method, which comprises the following steps:

a: preparing tungsten cobalt solder powder: according to the actual using amount, weighing tungsten powder and cobalt powder according to the weight ratio of 2:7, placing the tungsten powder and the cobalt powder in an agate mortar, stirring the mixture with a pestle for 50-60 minutes until the tungsten powder and the cobalt powder are fully mixed, and finally placing the prepared tungsten-cobalt solder powder 3 in a weighing bottle for later use, wherein the melting temperature of the tungsten-cobalt solder powder is 1450-1500 ℃;

b: and (3) hot wire pins and hot wire purification treatment: soaking the cut hot wire pins 2 and the wound hot wire 1 by using an organic solvent trichloroethylene or acetone for deoiling, purifying the deoiled hot wire in a hydrogen atmosphere, wherein the purification treatment process is specified to be that the temperature is 900-1100 ℃, and the temperature is kept for 3-10 minutes, wherein the wound hot wire 1 can be wound into a single-spiral shape, the single-spiral hot wire can be further processed into a double-spiral shape or a incense coil shape, and the hot wire 1 is made of thorium tungsten alloy wires with the brand number WTH10 or WTH 15;

c: assembling the hot wire pin with the hot wire: c, arranging the leads 2 of the hot wire pins purified in the step b at two ends of the hot wire 1, wherein one end of each lead is inserted into 4-8 circles of the spiral line of the hot wire 1 or one end of each lead is inserted into the position of 5-10 mm of the spiral line of the hot wire 1, and the leads and the hot wire 1 can be pre-fixed in a laser welding mode at proper time, wherein the leads 2 of the hot wire pins are made of one of tungsten, molybdenum, tungsten-rhenium, molybdenum-rhenium and the like;

d: coating of tungsten cobalt solder powder: b, adding 15-30 mL of nitrocotton solution into the tungsten-cobalt solder powder 3 prepared in the step a according to the weight of 100g to prepare a coating solder, fully stirring and blending the solder into a paste, then brushing 3 the tungsten-cobalt solder on the joint of the hot wire pin 2 and the hot wire 1 assembled in the step c by using a writing brush, and after the coating is finished, baking in an oven at the baking temperature of 80-100 ℃ for 10-20 minutes;

e: welding a hydrogen furnace: d, placing the assembly coated with the solder in the step d into a welding furnace in hydrogen atmosphere for brazing, wherein the brazing temperature is 1450-1500 ℃, and the brazing time is 1-2 minutes;

f: and (3) brazing quality detection: the brazing quality is observed under a microscope, the solder flows uniformly, and the gap between the hot wire pin 2 and the hot wire 1 is fully filled with the solder, so that the brazing of the thorium tungsten hot wire and the hot wire pin 2 is completed.

With a conventional thorium tungsten hot wire, the vacuum device start-up time is typically 3 minutes, which the present invention can reduce to 2 minutes.

While there have been shown and described what are at present considered the fundamental principles of the invention, its essential features and advantages, it will be understood by those skilled in the art that the invention is not limited by the foregoing embodiments, which are merely illustrative of the principles of the invention, but is capable of numerous changes and modifications without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.