WO2017113382A1

WO2017113382A1 - Carburising treatment process for thorium-tungsten electrode

Info

Publication number: WO2017113382A1
Application number: PCT/CN2015/100300
Authority: WO
Inventors: 蔡志国; 谭翠丽; 张米好; 杨洋
Original assignee: 深圳凯世光研股份有限公司
Priority date: 2015-12-31
Filing date: 2015-12-31
Publication date: 2017-07-06

Abstract

A carburising treatment process for a thorium-tungsten electrode, the electrode being subjected to pre-treatment, hydrogen burning, carbon coating, high frequency treatment, secondary carbon coating, and high-temperature vacuum treatment. For the high frequency processing of the electrode, concentrated heating of a high frequency coil can cause a phase change of the electrode material, the carbon atoms extending deeply into the metal, and the carbon material permeating deeper into the electrode surface.

Description

Description: The invention relates to a carburizing treatment process of tantalum tungsten electrode

[0001] The present invention relates to a carburizing treatment method for the manufacture of ultra high pressure short arc lamps, and more particularly to a tantalum tungsten electrode carburizing treatment process.

Background technique

[0002] The cathodes of short-arc mercury lamps and xenon lamps are made of tantalum-tungsten material, which emits electrons after being energized to produce light, which is a core component of power products. The cathode without surface carbonization is unstable, which is easy to cause stroboscopic and arcing.

Problems such as large light decay have severely restricted the use effect and longevity of the product.

[0003] Chinese patent CN101967654A "Using a titanium substrate to carburize modified cerium-containing oxide electrode material and preparation method" in the electrode material is carburized, the titanium substrate is heated pickling, water washing, and drying High temperature carburization was then carried out.

[0004] Chinese Patent No. CN102828143A discloses a high temperature carburizing process for a workpiece in which high temperature carburizing is divided into two stages, a temperature of 980 ° C in the first half and a temperature of 1010 ° C in the second half.

[0005] In the above carburizing process, simply modifying the material by high-temperature carburizing improves the mechanical stability of the material, and the mechanism of improving the electron-emitting performance of the carburizing process of the present invention is different, and the carbon material penetrates into the surface of the material. It is shallow and affects the life of the material.

technical problem

In order to solve the above problems, an object of the present invention is to provide a carburizing treatment process for a tantalum tungsten electrode, which aims to solve the problem of limited carburization of the tantalum tungsten electrode, so that the carbon powder penetrates deeper in the surface layer of the tantalum tungsten electrode, and the electrode is increased. Service life.

Problem solution

Technical solution

[0007] The technical solution adopted by the present invention to solve the above technical problems is:

[0008] A method for carburizing a tantalum tungsten electrode adopts the following steps:

[0009] Step (1): pre-treating, cleaning the electrode and the presser, and then drying;

[0010] Step (2): burning hydrogen, the pretreated electrode is subjected to high temperature hydrogen burning at a temperature of 950 to 1200 ° C, After cooling to normal temperature;

[0011] Step (3): coating carbon, coating carbon powder on the surface of the electrode and the inner surface of the presser, coating a total thickness of 0.6 mm - 1.2 mm, and then drying;

[0012] Step (4): high-frequency treatment, placing the electrode coated with carbon powder in a presser coated with carbon powder, the electrode is placed in the middle portion of the high-frequency coil, and the high-frequency coil used for high-frequency processing The current gradually increases and stays at the maximum current for 10 to 15 minutes, then anneals in the high frequency coil, and cools the electrode to 550~600.

°C, then take out and naturally cool to normal temperature;

[0013] Step (5): secondary carbon coating, coating the surface of the high frequency treated electrode and the inner surface of the presser with carbon powder

, the total thickness of the coating is about 0.6mm~1.2mm, and then dried;

[0014] Step (6): high-temperature vacuum treatment, re-coating the high-frequency treated electrode with carbon powder, performing high-temperature vacuum treatment, increasing the temperature, staying at the highest temperature for 2~3h, then annealing and then cooling, A carburized layer is formed on the surface of the electrode.

[0015] Preferably, in the step (1), the cleaning process is: sequentially cleaning the electrode and the pressure tool with an alkali solution, an acid solution, a hydrogen peroxide solution, a formic acid solution, and the cleaning process is: placing the electrode in the alkali solution In the middle, the ultrasonic wave is shaken, taken out, and then washed in 99.999% pure water. Then the electrode cleaned with pure water is placed in the acid solution, ultrasonically shaken, taken out, washed in pure water, taken out, and then Put in a solution of H ₂ 0 ₂ : CH ₂ 0 ₂ : H ₂ 0 in a volume ratio of 1: 1: 1, ultrasonically shake, then rinse with pure water, then add 99.999% hot pure water for ultrasonic cleaning, and finally use Alcohol is dehydrated and dried.

[0016] Preferably, in the step (3), the surface of the electrode and the inner surface of the presser are coated with at least 2 layers of carbon, and each layer is coated with a thickness of 0.2 mm to 0.5 mm _{; in} step (5), the electrode The surface of the surface and the inner surface of the presser is coated with at least 2 layers of carbon, and each layer is coated with a carbon thickness of 0.2 mm to 0.5 mm.

[0017] Preferably, in step (3), the surface of the electrode and the inner surface of the press are coated with 3 layers of carbon, and each layer is coated with a thickness of 0.2 mm; in step (5), the surface of the electrode and the presser The inner surface is coated with 3 layers of carbon, and each layer is coated with a carbon thickness of 0.2 mm.

[0018] Preferably, the dispersant and the carbon powder used in the step (3) and the step (5) have the same concentration, and the carbon powder is coated by dispersing the carbon powder in a mixed solvent of butyl acetate and nitrocellulose, and dispersing The concentration is 20%~25<3⁄4, and the above solution with carbon powder is coated on the surface of the electrode and the inner surface of the press, and then dried. [0019] In the carbon coating process, the surface of the electrode and the inner surface of the presser are coated with carbon from one-time carbon coating to multiple carbon coating, in order to coat the carbon layer more uniformly, high-frequency carburizing and high In vacuum carburizing, carburization is more uniform, prolonging the life of the electrode.

[0020] Preferably, in step (4), the current of the high frequency processing is stepped up, and the maximum current of the high frequency processing is 45~50A.

[0021] Preferably, in step (4), after high frequency processing, the electrode temperature is gradually increased, and the maximum temperature range is 150 0 to 1800. C.

[0022] Preferably, in step (6), the temperature is gradually increased from 0 ° C to 1000 ° C, then stay for 10 minutes, continue to heat up, the maximum temperature is 1750 ~ 2100 ° C, and then stay at the highest temperature 2 2 ~ 3h, then annealed to 60 0~700 °C, then naturally cooled.

[0023] A tantalum tungsten electrode produced by the above process, the carburized layer of the tantalum tungsten electrode, having a thickness of 80 μηι to 110 μm.

Advantageous effects of the invention

Beneficial effect

[0024] In the present invention, the electrode is protected by a presser to avoid carbon loss or evaporation. In the step (2), high temperature hydrogen burning can remove impurities, ensure the purity of the electrode material, and prevent the bulb from being blackened. , to avoid problems such as weakened light intensity. Due to the high frequency treatment of the electrode during the carburizing process, the step (4) electrode material phase change, the carbon atom easily penetrates into the metal interior, and the electrode is twice coated with carbon, as in steps (3) and (5), The same is to enable the electrode material to be combined with carbon to a maximum extent to form a thick carburized layer, which can increase the electrode life.

Brief description of the drawing

DRAWINGS

[0025] FIG. 1 : High-frequency processing current variation curve of Embodiment 1

2: High vacuum processing temperature change curve of Example 1

BEST MODE FOR CARRYING OUT THE INVENTION

[0027] The paragraphs describing the best mode of the invention are entered here. Embodiments of the invention

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0029] Embodiment 1,

[0030] The step of carburizing the tungsten electrode is as follows:

[0031] (1) Electrode pretreatment: The electrode is first placed in a 0.06 g/mL NaOH solution, and ultrasonically shaken for 15 min.

, then rinse with distilled water and then place HC1:H ₂

0 in a volume ratio of 1: 1 solution, ultrasonically shake for 10 min, then rinse with distilled water, then place the electrode in a solution of H ₂ 0 ₂ : CH ₂ 0 ₂ : H ₂ 0 of 1: 1:1, ultrasonically oscillate for 10 min. Then, it is washed with distilled water, ultrasonically cleaned in hot pure water, dehydrated with alcohol, and dried with a hot air blower.

[0032] The processing method of the presser is the same as above.

(2) Hydrogen burning: The electrode and the presser were respectively subjected to hydrogen reduction under conditions of 1000 ° C to remove impurities in the electrode material, and then cooled to normal temperature.

[0034] (3) carbon coating: on the surface of the electrode and the inner surface of the press is coated with a 20% carbonic acid butyl acetate-nitrocellulose solution, placed in a 50 ° C constant temperature drying oven for drying, carbon powder The thickness is about 0.2 mm, and then the above carbon coating method is repeated twice, and the total thickness of the carbon powder on the surface of the crucible electrode is 0.6 mm.

[0035] (4) High-frequency treatment: The electrode coated with carbon powder is placed in a presser coated with carbon powder, and the electrode is placed in the middle portion of the high-frequency coil, according to the current change curve shown in FIG. High-frequency treatment, the processing method is: the current of 17A will be passed for 2 minutes, the electrode and the press will be preheated, then the current will increase to 25A, heat for 5 minutes, then the current will increase to 45A, and the current will stay at 45A. Minutes, during this process, the electrode temperature gradually rises to a temperature of up to 1500 ° C. After 10 minutes, the electrode is annealed, the electrode is cooled to 550 ° C, and then naturally cooled to room temperature.

[0036] (5) Secondary carbon coating: The surface of the electrode and the inner surface of the presser are again coated with an organic solution containing carbon powder, dried, and then carbon coated twice, and the total thickness of the coating is 0.6. Mm.

[0037] (6) High-temperature vacuum treatment: The electrode is placed in the press, and the electrode is treated according to the temperature change curve shown in FIG. 2, the temperature is gradually increased from the normal temperature, and when the temperature is raised to 1000 ° C, the heat is maintained. 10 minutes, at The metallographic structure is homogenized in this section, and the electrode is heated more evenly to achieve the tissue transformation required for temperature rise.

[0038] Then the temperature continues to rise to 1750 ° C, stay at 1750 ° C for 2.5 h, then annealed to 600 ° C, and then naturally cooled to room temperature, forming a uniform W ₂ C carburized layer on the surface of the electrode, the internal grain boundary is Granular texture, grainy grain of the grain can stabilize the light of the electrode and slow down the consumption of the electrode.

[0039] The thickness of the carburized layer was measured by a metallographic microscope to be 100 μm.

[0040] Embodiment 2

[0041] The step of carburizing the tungsten electrode is as follows:

[0042] (1) Electrode pretreatment: First, the electrode is placed in a 0.06 g/mL NaOH solution, and the ultrasonic vibration is lOmin.

, then rinse with distilled water, then place HCl: H ₂

0 in a volume ratio of 1:1 solution, ultrasonically oscillated for 10 min, then rinsed with distilled water, and then the electrode was placed in a solution of ₂ 0 ₂ : CH ₂ 0 ₂ : H ₂ 0 of 1: 1:1, ultrasonically oscillated for 10 min, Then, it is washed with distilled water, ultrasonically cleaned in hot pure water, dehydrated with alcohol, and dried by a hot air blower.

[0043] The processing method of the presser is the same as above.

(2) Hydrogen burning: The electrode and the presser were respectively subjected to hydrogen reduction under the condition of 1200 ° C to remove impurities in the electrode material.

[0045] (3) carbon coating: coating the surface of the electrode and the inner surface of the press with an organic butyl acetate-nitrocellulose solution containing a carbon powder concentration of 25%, placed in a constant temperature drying oven at 50 ° C, dried, carbon powder The thickness was 0.5 mm, and then coated again, dried, and the total thickness of the twice coated toner was 1.0 mm.

[0046] (4) High-frequency treatment: the electrode coated with carbon powder is placed in a presser coated with carbon powder, and the electrode is placed in the middle portion of the high-frequency coil for high-frequency treatment, and the treatment method is Passing the current of 18A for 2 minutes, preheating the electrode and presser, then increasing the current to 25A, heating for 5 minutes, then increasing the current to 5 OA, and staying, the temperature of the electrode is gradually increased, the highest temperature After reaching 1800 ° C, the current of 50 A was left to stand for 15 minutes, and then the electrode was cooled to 600 ° C, and then taken out and naturally cooled to normal temperature.

(5) Secondary carbon coating: The surface of the electrode and the inner surface of the presser were again coated with an organic solution containing carbon powder, dried, and the total thickness of the coating was repeated four times with a thickness of 1.2 mm.

[0048] (6) High-temperature vacuum treatment: The electrode is placed in the press, the temperature is raised from normal temperature to 2100 ° C, stayed at 2100 ° C for 3 h, then annealed to 700 ° C, and then naturally cooled to room temperature to form on the electrode surface. Uniform W ₂ C Carburized layer, internal grain boundary is granular texture.

[0049] The thickness of the carburized layer was measured by a metallographic microscope to be 80 μm.

[0050] Embodiment 3

[0051] The step of carburizing the tungsten electrode is as follows:

[0052] (1) Pretreatment of the electrode: First, the electrode is placed in a 0.06 g/mL NaOH solution, ultrasonically shaken, then washed with distilled water, and then placed in a 1:1 HCl solution, ultrasonically shaken, and then used. Rinse with distilled water and place the electrode in 11 ₂ 0 _2:. 8 ₂ 0 _2: H ₂ 0 is 1: 1: 1 solution, ultrasonically shaken, then washed with distilled water, and then placed in hot pure water for ultrasonic cleaning, then dehydrated with alcohol, and then dried with a hot air blower.

[0053] The processing method of the presser is the same as above.

(2) Hydrogen burning: The electrode and the presser were respectively subjected to hydrogen reduction under conditions of 1000 ° C to remove impurities in the electrode material.

(3) Carbon coating: An organic solution containing a carbon powder concentration of 23% was applied to the surface of the electrode and the inner surface of the presser three times, and the total thickness of the carbon powder after drying was 0.8 mm.

[0056] (4) High-frequency treatment: The electrode coated with carbon powder is placed in a presser coated with carbon powder, and the electrode is located in the middle portion of the high-frequency coil, and is high according to the current change curve shown in FIG. Frequency processing, the processing method is: the current of 17A will be passed for 2 minutes, the electrode and the presser are preheated, then the current is increased to 25A, heated for 5 minutes, then the current is increased to 45A, and the temperature is maintained. Continued to rise, the maximum temperature reached 1 750 ° C, the current of 45 A stayed for 6 minutes and then annealed, the electrode was cooled to 550 ° C, and then naturally cooled to room temperature.

(5) Secondary carbon coating: The surface of the electrode and the inner surface of the presser were again coated with the organic solution containing carbon powder three times, and the total thickness of the carbon powder after drying was 0.8 mm.

[0058] (6) High-temperature vacuum treatment: the electrode is placed in the press, the temperature is raised from normal temperature to 2000 ° C, stayed at 2000 ° C for 2 h, then annealed to 680 ° C, and then naturally cooled to room temperature, on the electrode surface A uniform W ₂ C carburized layer is formed, and the inner grain boundary is a granular texture.

[0059] The thickness of the carburized layer measured by a metallographic microscope was 80 μm.

The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, and any person skilled in the art can easily think of within the technical scope disclosed by the present invention. Changes or substitutions are intended to be included within the scope of the invention. Therefore, the scope of protection of the present invention The scope of protection of the claims shall prevail.

Claims

Claim

[Claim 1] A process for carburizing a tantalum tungsten electrode, characterized in that the following steps are taken:

[Claim 2] Step (1): Pretreatment, cleaning the electrode and the press, and then drying;

[Claim 3] Step (2): Hydrogen burning, high temperature hydrogen burning of the pretreated electrode at a temperature of 950 12

00 ° C, and then cooled to room temperature;

[Claim 4] Step (3): coating carbon, applying carbon powder on the surface of the electrode and the inner surface of the presser, coating a total thickness of 0.6 mm to 1.2 mm, and then performing drying treatment;

[Claim 5] Step (4): High-frequency treatment, the electrode coated with carbon powder is placed in a presser coated with carbon powder, and the electrode is placed in the middle portion of the high-frequency coil, which is used for high-frequency processing. The current of the frequency coil gradually increases, and stays at the maximum current for 10 to 15 minutes, then anneals in the high frequency coil, cools the electrode to 550~600 °C, and then naturally cools to normal temperature;

[Claim 6] Step (5): secondary carbon coating, coating the surface of the high-frequency treated electrode and the inner surface of the press with a total thickness of 0.6 mm to 1.2 mm, followed by drying ;

[Claim 7] Step (6): High-temperature vacuum treatment, re-coating the high-frequency treated electrode with carbon powder, performing high-temperature vacuum treatment, increasing the temperature, staying at the highest temperature for 2~3h, then annealing and then cooling , a carburized layer is formed on the surface of the electrode.

[Claim 8] The carburizing treatment process of the tantalum tungsten electrode according to claim 1, wherein: in the step (1), the cleaning process is: sequentially using an alkali solution, an acid solution, and an electrode and a presser, respectively. The hydrogen peroxide solution and the formic acid solution are cleaned. The cleaning process is as follows: the electrode is placed in an alkali solution, ultrasonically shaken, taken out, and then washed in 99.999% pure water; then the electrode cleaned with pure water is placed in the acid. In the solution, ultrasonically shake, take out, and then put it in pure water for cleaning, take it out; then put H ₂ 0 ₂ : CH ₂ 0 ₂ : H ₂ 0 in a volume ratio of 1: 1:1, the ultrasonic vibration, It is then washed with pure water, then ultrasonically cleaned with 99.999% hot water, finally dehydrated with alcohol and dried.

[Claim 9] The carburizing treatment process of the tantalum tungsten electrode according to claim 1, wherein: in the step (3), the surface of the electrode and the inner surface of the presser are coated with at least two layers of carbon layers, each layer The thickness of the coated carbon is 0.2 mm to 0.5 mm _{; in the} step (5), the surface of the electrode and the inner surface of the presser are coated with at least 2 layers of carbon, and the thickness of each layer is 0.2 mm to 0.5 mm. The carburizing treatment process of the tantalum tungsten electrode according to claim 3, wherein in the step (3), the surface of the electrode and the inner surface of the press are coated with 3 layers of carbon, and each layer is coated with a thickness of 0.2 mm. In step (5), the surface of the electrode and the inner surface of the presser are coated with 3 layers of carbon, and each layer is coated with a thickness of 0.2 mm.

The tantalum tungsten electrode carburizing treatment process according to claim 3, wherein:

(3) In step (5), the process of coating the carbon powder is to disperse the carbon powder in the butyl acetate-nitrocellulose solvent at a dispersion concentration of 20%~25<3⁄4, on the surface of the electrode and the pressure tool. The above formulated solution in which carbon powder is dispersed is applied to the surface, followed by drying.

The carburizing treatment process of the tantalum tungsten electrode according to claim 1, wherein in the step (4), the current of the high frequency processing is stepwisely increased, and the maximum current of the high frequency processing is 45 to 50 A.

The carburizing treatment process of the tantalum tungsten electrode according to claim 1, wherein in the step (4), the high temperature treatment is performed, and the temperature of the electrode is gradually increased, and the maximum temperature range is 1500 to 180 0. C.

The tantalum tungsten electrode carburizing treatment process according to claim 1, wherein in step (6), the temperature is gradually increased from room temperature, the maximum temperature is 1750-2100 ° C, and then stays at the highest temperature 2 2~ 3h, then annealed to 600~700 °C, then naturally cooled.

A tantalum tungsten electrode produced by the process of any of 1 to 8, characterized in that: the carburized layer of the tantalum tungsten electrode has a thickness of 80 μηι to 110 μιη.