Welding method of ceramic heater electrode

Abstract

The invention relates to a welding method of a ceramic heater electrode, in particular to the field of welding, and the welding method comprises the following steps: sequentially assembling an electrode stem, a soldering lug and a Kovar alloy sheet along the axial direction of the electrode stem to obtain an assembly; and placing the assembly in a hollow soldering lug cylinder, then placing the hollow soldering lug cylinder in a hollow single-face open sleeve to form the assembly, and then sequentially carrying out degassing and hot isostatic pressing welding to obtain the ceramic heater electrode. According to the welding method, the welding connector of the electrode is designed, efficient welding of the ceramic heater electrode is achieved, an electrode product obtained through welding has good welding uniformity and welding strength, the use effect of the electrode is guaranteed, and cracking of a ceramic base body in the heating process is avoided.

Description

Technical Field

[0001] This invention relates to the field of welding, and more specifically to a welding method for ceramic heater electrodes. Background Technology

[0002] Chemical vapor deposition (CVD) equipment is a core component of semiconductor chip manufacturing, and its key technology lies in ensuring the uniformity and repeatability of material growth. As a critical component of the CVD reaction chamber, the chip heating plate (usually made of ceramic) bears the crucial responsibility of uniformly heating the silicon wafer and promoting gas ionization to form a uniform plasma deposition layer. Radio frequency electrodes and heating components are pre-embedded within the heating plate, which need to be welded to external nickel electrode rods to introduce power. However, this welding process faces significant challenges: the heating plate fabrication requires exposure to high temperatures of 1700-1900℃, and its internal electrodes must be made of high-temperature resistant tungsten or molybdenum materials with thermal expansion coefficients close to those of aluminum nitride ceramics. However, the thermal expansion coefficients of these two materials differ significantly from those of the external nickel electrode rods. Improper welding design or process can easily lead to cracking of the ceramic substrate near the connection point due to thermal stress, rendering the entire expensive heating plate unusable.

[0003] Therefore, how to achieve reliable, low-stress welding between the tungsten / molybdenum electrode and the nickel electrode rod is a decisive factor in determining the performance of the ceramic heating plate (which in turn affects the uniformity and repeatability of the CVD process) and even the success or failure of the preparation.

[0004] The prior art CN216982138U discloses a "structure of lead-out electrodes for ceramic heating plates", which uses gold, Kovar alloy, silver-copper-nickel alloy, and gold-nickel alloy as solder, and uses vacuum brazing to weld the electrode rods of the ceramic heater.

[0005] However, current brazing methods suffer from low weld strength due to uneven filler metal and welding defects. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a welding method for ceramic heater electrodes, so as to solve the defects of poor welding uniformity and low welding strength in the current welding method.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] This invention provides a method for welding electrodes for a ceramic heater, the welding method comprising:

[0009] The electrode rod, welding sheet, and Kovar alloy sheet are assembled sequentially along the axial direction of the electrode rod to obtain the assembly.

[0010] The assembly is placed inside a hollow welding tube and then inside a hollow single-sided open sleeve to form an assembly. After that, degassing and hot isostatic pressing are performed in sequence to obtain the ceramic heater electrode.

[0011] The welding method provided by this invention achieves efficient welding of ceramic heater electrodes by designing the welding joint of the electrodes. The welded electrode products have good welding uniformity and welding strength, which helps to ensure the performance of the electrodes and avoid cracking of the ceramic matrix during heating.

[0012] As a preferred embodiment of the present invention, the electrode rod, welding sheet, Kovar alloy sheet and hollow welding sheet cylinder are all cleaned.

[0013] Preferably, the electrode rod is made of pure nickel.

[0014] As a preferred embodiment of the present invention, the welding sheet undergoes vacuum heat treatment.

[0015] Preferably, the temperature of the vacuum heat treatment is 700-800℃.

[0016] Preferably, the vacuum heat treatment time is 5-15 minutes.

[0017] As a preferred embodiment of the present invention, the thickness of the welding sheet is 0.1-0.2 mm.

[0018] Preferably, the material of the solder sheet includes a gold-nickel alloy.

[0019] Preferably, the diameter of the welding sheet is equal to the bottom diameter of the electrode rod.

[0020] As a preferred embodiment of the present invention, the thickness of the Kovar alloy sheet is 1-2.5 mm.

[0021] Preferably, the diameter of the Kovar alloy sheet is equal to the bottom diameter of the electrode rod.

[0022] As a preferred embodiment of the present invention, the wall thickness of the hollow welding tube is 0.1-0.2 mm.

[0023] Preferably, the hollow welding tube is made of a gold-nickel alloy.

[0024] Preferably, the inner diameter of the hollow welding tube is equal to the bottom diameter of the electrode rod.

[0025] Preferably, the hollow single-sided open sleeve is made of pure nickel.

[0026] Preferably, the inner diameter of the hollow single-sided open sleeve is equal to the outer diameter of the hollow welded sheet cylinder.

[0027] Preferably, the wall thickness of the hollow single-sided open sleeve is 0.2-1mm.

[0028] As a preferred technical solution of the present invention, the degassing operation temperature is 200-300℃.

[0029] Preferably, the absolute vacuum degree of the degassing is ≤0.001Pa.

[0030] As a preferred embodiment of the present invention, the degassing time is 10-15 minutes.

[0031] As a preferred embodiment of the present invention, the heating rate of the hot isostatic pressing welding is 5-10℃ / min;

[0032] Preferably, the holding temperature for hot isostatic pressing welding is 500-900℃;

[0033] Preferably, the pressure of the hot isostatic pressing is 100-150 MPa.

[0034] As a preferred technical solution of the present invention, the heat preservation and pressure holding time for hot isostatic pressing is 12-14 hours.

[0035] Compared with existing technical solutions, the present invention has the following beneficial effects:

[0036] The welding method provided by this invention can achieve effective welding of electrodes, and has the advantages of uniform welding and high welding strength. The welding uniformity of the obtained welding electrode product is ≥95.2% and the welding strength is ≥70.6MPa. Under the preferred scheme, the welding uniformity of the obtained welding electrode product is ≥98% and the welding strength is ≥100MPa. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the assembly in an embodiment of the present invention.

[0038] In the diagram: 100 - electrode rod, 200 - welding sheet, 300 - Kova alloy sheet, 400 - hollow welding sheet tube, 500 - hollow single-sided open sleeve.

[0039] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0040] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0041] I. This embodiment provides a welding method for ceramic heater electrodes, the welding method comprising:

[0042] The electrode rod 100, the welding piece 200 and the Kovar alloy piece 300 are assembled sequentially along the axial direction of the electrode rod 100 to obtain the assembly.

[0043] The assembly is placed inside the hollow welding sheet cylinder 400 and then inside the hollow single-sided open sleeve 500 to form the assembly. Figure 1 As shown, degassing and hot isostatic pressing welding are then performed sequentially to obtain the ceramic heater electrode.

[0044] In this invention, when assembling the various components, it is necessary to ensure that there is a certain assembly gap between the components to ensure that the components can be installed quickly without affecting the final welding effect.

[0045] The electrode rod 100, welding sheet 200, Kovar alloy sheet 300 and hollow welding sheet cylinder 400 are all cleaned.

[0046] In this invention, the cleaning process can be carried out by using one or more cleaning media such as degreaser, rust remover, alcohol, ketone, water, acid or alkali in a stepwise cleaning manner to remove rust, oil stains, dust and other impurities that affect welding from the surface. Furthermore, the cleaning process can be enhanced by means of ultrasound and / or microwave to enhance the cleaning effect. An exemplary cleaning process is as follows: degreaser, rust remover and isopropanol are ultrasonically cleaned for 5-10 minutes each, followed by cleaning with 10-30% nitric acid at room temperature for 5-15 minutes, rinsing with pure water and drying at 50-100℃ for ≥1 hour.

[0047] The electrode rod 100 is made of pure nickel.

[0048] In this invention, the purity of the pure nickel is ≥99.9%.

[0049] The welding sheet 200 is subjected to vacuum heat treatment.

[0050] The temperature of the vacuum heat treatment is 700-800℃, for example, it can be 700℃, 710℃, 720℃, 730℃, 740℃, 750℃, 760℃, 770℃, 780℃, 790℃ or 800℃, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0051] The vacuum heat treatment time is 5-15 min, for example, it can be 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min or 15 min, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0052] The thickness of the welding sheet 200 is 0.1-0.2mm, for example, it can be 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm or 0.2mm, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0053] The material of the welding piece 200 includes: gold-nickel alloy.

[0054] In this invention, the nickel mass percentage in the gold-nickel alloy is 15-25%, for example, it can be 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24% or 25%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0055] The diameter of the welding sheet 200 is equal to the bottom diameter of the electrode rod 100.

[0056] The thickness of the Kovar alloy sheet 300 is 1-2.5mm, for example, it can be 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm or 2.5mm, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0057] The diameter of the Kovar alloy sheet 300 is equal to the bottom diameter of the electrode rod 100.

[0058] The wall thickness of the hollow welding tube 400 is 0.1-0.2 mm, for example, it can be 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm or 0.2 mm, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0059] The hollow welding tube 400 is made of a gold-nickel alloy.

[0060] The inner diameter of the hollow welding tube 400 is equal to the bottom diameter of the electrode rod 100.

[0061] The hollow single-sided open sleeve 500 is made of pure nickel.

[0062] The inner diameter of the hollow single-sided open sleeve 500 is equal to the outer diameter of the hollow welded sheet cylinder 400.

[0063] The wall thickness of the hollow single-sided open sleeve 500 is 0.2-1mm, for example, it can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1mm, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0064] In this invention, the welding area needs to be encased before degassing. This is done by sealing the welding area with a cavity, the surface of which is provided with pores for degassing. In this invention, a hollow single-sided open sleeve 500 is used for encasing and also serves as part of the electrode. The sealing between the hollow single-sided open sleeve 500 and the welding area is achieved by electron beam welding (accelerating voltage 60-80kV, beam current 5-30mA, welding speed 15-20mm / s, vacuum degree ≤0.005Pa). After hot isostatic pressing welding, the bottom of the hollow single-sided open sleeve 500 is removed by machining or other methods to expose the Kova alloy, thus obtaining the ceramic heater electrode.

[0065] The degassing operating temperature is 200-300℃, for example, it can be 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃ or 300℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0066] Wherein, the absolute vacuum degree of degassing is ≤0.001Pa, for example, it can be 0.001Pa, 0.0009Pa, 0.0008Pa, 0.0007Pa, 0.0006Pa, 0.0005Pa, 0.0004Pa, 0.0003Pa, 0.0002Pa or 0.0001Pa, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0067] The degassing time is 10-15 min, for example, it can be 10 min, 10.5 min, 11 min, 11.5 min, 12 min, 12.5 min, 13 min, 13.5 min, 14 min, 14.5 min or 15 min, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0068] The heating rate of the hot isostatic pressing welding is 5-10℃ / min, for example, it can be 5℃ / min, 5.5℃ / min, 6℃ / min, 6.5℃ / min, 7℃ / min, 7.5℃ / min, 8℃ / min, 8.5℃ / min, 9℃ / min, 9.5℃ / min or 10℃ / min, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0069] The heat preservation temperature for hot isostatic pressing welding is 500-900℃, for example, it can be 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃ or 900℃, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0070] The pressure of the hot isostatic pressing welding is 100-150 MPa, for example, it can be 100 MPa, 105 MPa, 110 MPa, 115 MPa, 120 MPa, 125 MPa, 130 MPa, 135 MPa, 140 MPa, 145 MPa or 150 MPa, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0071] The heat preservation and pressure holding time for hot isostatic pressing is 12-14 hours, for example, it can be 12 hours, 12.5 hours, 13 hours, 13.5 hours or 14 hours, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0072] II. To illustrate the excellent welding effect achievable by the ceramic heater electrode obtained by the welding method of the ceramic heater electrode provided by the present invention, the following practical example is used for explanation:

[0073] Example 1

[0074] This embodiment provides a method for welding electrodes for a ceramic heater, the specific process of which is as follows:

[0075] The electrode rod 100, the welding piece 200 and the Kovar alloy piece 300 are assembled sequentially along the axial direction of the electrode rod 100 to obtain the assembly.

[0076] The assembly is placed inside the hollow welding tube 400 and then inside the hollow single-sided open sleeve 500 to form an assembly. After that, degassing and hot isostatic pressing welding are performed in sequence to obtain the ceramic heater electrode.

[0077] The electrode rod 100, welding sheet 200, Kovar alloy sheet 300 and hollow welding sheet cylinder 400 are all cleaned, specifically including: each is ultrasonically cleaned for 6 minutes in sequence with degreasing agent, rust remover and isopropanol, then cleaned with 25% nitric acid at room temperature (25°C) for 10 minutes, rinsed with pure water and dried at 60°C for 1.5 hours.

[0078] The electrode rod 100 is made of pure nickel with a purity of 99.99%.

[0079] The thickness of the welding piece 200 is 0.15 mm, the material is gold-nickel alloy (Ni mass percentage is 18%, balance is Au), the diameter of the welding piece 200 is equal to the bottom diameter of the electrode rod 100, and the welding piece 200 is subjected to vacuum heat treatment at a temperature of 750℃ for 10 min.

[0080] The thickness of the Kovar alloy sheet 300 is 1.5 mm, and the diameter of the Kovar alloy sheet 300 is equal to the bottom diameter of the electrode rod 100.

[0081] The hollow welding tube 400 has a wall thickness of 0.15 mm and is made of gold-nickel alloy (Ni mass percentage of 20%). The inner diameter of the hollow welding tube 400 is equal to the bottom diameter of the electrode rod 100.

[0082] The hollow single-sided open sleeve 500 is made of pure nickel with a purity of 99.9%. The inner diameter of the hollow single-sided open sleeve 500 is equal to the outer diameter of the hollow welded sheet cylinder 400, and the wall thickness of the hollow single-sided open sleeve 500 is 0.5 mm.

[0083] The degassing process is performed at a temperature of 250°C, an absolute vacuum of 0.001 Pa, and a time of 12 min.

[0084] The heating rate of the hot isostatic pressing welding is 6℃ / min, the holding temperature is 700℃, the pressure is 125MPa, and the holding time is 13h.

[0085] Example 2

[0086] This embodiment provides a method for welding electrodes for a ceramic heater, the specific process of which is as follows:

[0087] The electrode rod 100, the welding piece 200 and the Kovar alloy piece 300 are assembled sequentially along the axial direction of the electrode rod 100 to obtain the assembly.

[0088] The assembly is placed inside the hollow welding tube 400 and then inside the hollow single-sided open sleeve 500 to form an assembly. After that, degassing and hot isostatic pressing welding are performed in sequence to obtain the ceramic heater electrode.

[0089] The electrode rod 100, welding sheet 200, Kovar alloy sheet 300 and hollow welding sheet cylinder 400 are all cleaned, specifically including: each is ultrasonically cleaned for 8 minutes in sequence with degreasing agent, rust remover and isopropanol, then cleaned with 20% nitric acid at room temperature (25°C) for 12 minutes, rinsed with pure water and dried at 80°C for 1 hour.

[0090] The electrode rod 100 is made of pure nickel with a purity of 99.99%.

[0091] The thickness of the welding piece 200 is 0.12 mm, and the material is gold-nickel alloy (Ni mass percentage is 21%, balance is Au). The diameter of the welding piece 200 is equal to the bottom diameter of the electrode rod 100. The welding piece 200 is subjected to vacuum heat treatment at a temperature of 780℃ for 8 minutes.

[0092] The thickness of the Kovar alloy sheet 300 is 2mm, and the diameter of the Kovar alloy sheet 300 is equal to the bottom diameter of the electrode rod 100.

[0093] The hollow welding tube 400 has a wall thickness of 0.18 mm and is made of gold-nickel alloy (Ni mass percentage of 22%). The inner diameter of the hollow welding tube 400 is equal to the bottom diameter of the electrode rod 100.

[0094] The hollow single-sided open sleeve 500 is made of pure nickel with a purity of 99.9%. The inner diameter of the hollow single-sided open sleeve 500 is equal to the outer diameter of the hollow welded sheet sleeve 400, and the wall thickness of the hollow single-sided open sleeve 500 is 0.8 mm.

[0095] The degassing process is performed at a temperature of 280°C, an absolute vacuum of 0.0001 Pa, and a time of 14 min.

[0096] The heating rate for hot isostatic pressing (HIP) welding is 8℃ / min, the holding temperature is 800℃, the pressure is 130MPa, and the holding time is 12.5h.

[0097] Example 3

[0098] This embodiment provides a method for welding electrodes for a ceramic heater, the specific process of which is as follows:

[0099] The electrode rod 100, the welding piece 200 and the Kovar alloy piece 300 are assembled sequentially along the axial direction of the electrode rod 100 to obtain the assembly.

[0100] The assembly is placed inside the hollow welding tube 400 and then inside the hollow single-sided open sleeve 500 to form an assembly. After that, degassing and hot isostatic pressing welding are performed in sequence to obtain the ceramic heater electrode.

[0101] The electrode rod 100, welding sheet 200, Kovar alloy sheet 300 and hollow welding sheet cylinder 400 are all cleaned, specifically including: each is ultrasonically cleaned for 5 minutes in sequence with degreasing agent, rust remover and isopropanol, then cleaned with 30% nitric acid at room temperature (30°C) for 5 minutes, rinsed with pure water and dried at 100°C for 1 hour.

[0102] The electrode rod 100 is made of pure nickel with a purity of 99.99%.

[0103] The thickness of the welding piece 200 is 0.1 mm, the material is gold-nickel alloy (Ni mass percentage is 15%, balance is Au), the diameter of the welding piece 200 is equal to the bottom diameter of the electrode rod 100, and the welding piece 200 is subjected to vacuum heat treatment at a temperature of 700℃ for 15 min.

[0104] The thickness of the Kovar alloy sheet 300 is 1 mm, and the diameter of the Kovar alloy sheet 300 is equal to the bottom diameter of the electrode rod 100.

[0105] The hollow welding tube 400 has a wall thickness of 0.2 mm and is made of gold-nickel alloy (Ni mass percentage is 15%, balance is Au). The inner diameter of the hollow welding tube 400 is equal to the bottom diameter of the electrode rod 100.

[0106] The hollow single-sided open sleeve 500 is made of pure nickel with a purity of 99.9%. The inner diameter of the hollow single-sided open sleeve 500 is equal to the outer diameter of the hollow welded sheet cylinder 400, and the wall thickness of the hollow single-sided open sleeve 500 is 0.2 mm.

[0107] The degassing process is performed at a temperature of 200°C, an absolute vacuum of 0.0008 Pa, and a time of 15 minutes.

[0108] The heating rate of the hot isostatic pressing welding is 5℃ / min, the holding temperature is 500℃, the pressure is 150MPa, and the holding time is 14h.

[0109] Example 4

[0110] This embodiment provides a method for welding electrodes for a ceramic heater, the specific process of which is as follows:

[0111] The electrode rod 100, the welding piece 200 and the Kovar alloy piece 300 are assembled sequentially along the axial direction of the electrode rod 100 to obtain the assembly.

[0112] The assembly is placed inside the hollow welding tube 400 and then inside the hollow single-sided open sleeve 500 to form an assembly. After that, degassing and hot isostatic pressing welding are performed in sequence to obtain the ceramic heater electrode.

[0113] The electrode rod 100, welding sheet 200, Kovar alloy sheet 300 and hollow welding sheet cylinder 400 are all cleaned, specifically including: each is ultrasonically cleaned for 10 minutes in sequence with degreasing agent, rust remover and isopropanol, then cleaned with 10% nitric acid at room temperature 25°C for 15 minutes, rinsed with pure water and dried at 50°C for 2 hours.

[0114] The electrode rod 100 is made of pure nickel with a purity of 99.99%.

[0115] The thickness of the welding piece 200 is 0.2 mm, and the material is gold-nickel alloy (Ni mass percentage is 25%, balance is Au). The diameter of the welding piece 200 is equal to the bottom diameter of the electrode rod 100. The welding piece 200 is subjected to vacuum heat treatment at a temperature of 800℃ for 5 minutes.

[0116] The thickness of the Kovar alloy sheet 300 is 2.5 mm, and the diameter of the Kovar alloy sheet 300 is equal to the bottom diameter of the electrode rod 100.

[0117] The hollow welding tube 400 has a wall thickness of 0.1 mm and is made of gold-nickel alloy (Ni mass percentage is 25%, balance is Au). The inner diameter of the hollow welding tube 400 is equal to the bottom diameter of the electrode rod 100.

[0118] The hollow single-sided open sleeve 500 is made of pure nickel with a purity of 99.9%. The inner diameter of the hollow single-sided open sleeve 500 is equal to the outer diameter of the hollow welded sheet cylinder 400, and the wall thickness of the hollow single-sided open sleeve 500 is 1mm.

[0119] The degassing process is performed at a temperature of 300°C, an absolute vacuum of 0.0005 Pa, and a time of 10 min.

[0120] The heating rate of the hot isostatic pressing welding is 10℃ / min, the holding temperature is 900℃, the pressure is 100MPa, and the holding time is 12h.

[0121] Comparative Example 1

[0122] The only difference from Example 1 is that the solder pad 200 is not provided.

[0123] Comparative Example 2

[0124] The only difference from Example 1 is that the hollow welding tube 400 is not provided.

[0125] Example 5

[0126] The only difference from Example 1 is that the solder sheet 200 is not subjected to vacuum heat treatment.

[0127] Example 6

[0128] The only difference from Example 1 is that the vacuum heat treatment temperature of the solder sheet 200 is 500°C.

[0129] Example 7

[0130] The only difference from Example 1 is that the vacuum heat treatment temperature of the solder sheet 200 is 900°C.

[0131] Example 8

[0132] The only difference from Example 1 is that the Ni mass percentage in solder sheet 200 is 10%.

[0133] Example 9

[0134] The only difference from Example 1 is that the Ni mass percentage in solder sheet 200 is 30%.

[0135] The ceramic heater electrode products obtained in the above embodiments and comparative examples were subjected to welding uniformity tests and welding bond strength tests. The welding uniformity test was conducted using ultrasonic testing technology. The welding interface was analyzed by ultrasonic waves to determine the proportion of unbonded defects such as pores on the welding interface. The welding bond strength was tested in accordance with GB / T39163-2020 "Test Method for Bond Strength of Target Material and Backing Plate". The results are shown in Table 1 below.

[0136] Table 1

[0137] Weld uniformity / % Welding strength / MPa Example 1 98.5 102.1 Example 2 98.6 103.8 Example 3 99.1 105.6 Example 4 98.9 103.4 Comparative Example 1 89.6 53.6 Comparative Example 2 85.4 56.8 Example 5 95.2 70.6 Example 6 96.5 75.9 Example 7 97.3 84.3 Example 8 95.3 72.3 Example 9 94.7 74.8

[0138] As shown in Table 1, the solution provided by the present invention achieves efficient welding of ceramic heater electrodes by designing the welding joint of the electrodes. The welded electrode products have good welding uniformity and welding strength, which helps to ensure the performance of the electrodes and avoid cracking of the ceramic matrix during heating.

[0139] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0140] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0141] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for welding electrodes for a ceramic heater, characterized in that, The welding method includes: The electrode rod, welding sheet, and Kovar alloy sheet are assembled sequentially along the axial direction of the electrode rod to obtain the assembly. The assembly is placed inside a hollow welding tube and then inside a hollow single-sided open sleeve to form an assembly. After that, degassing and hot isostatic pressing are performed in sequence to obtain the ceramic heater electrode.

2. The welding method as described in claim 1, characterized in that, The electrode rod, welding sheet, Kovar alloy sheet, and hollow welding sheet cylinder are all cleaned. Preferably, the electrode rod is made of pure nickel.

3. The welding method as described in claim 1 or 2, characterized in that, The welding sheet undergoes vacuum heat treatment; Preferably, the temperature of the vacuum heat treatment is 700-800℃; Preferably, the vacuum heat treatment time is 5-15 minutes.

4. The welding method according to any one of claims 1-3, characterized in that, The thickness of the welding sheet is 0.1-0.2 mm; Preferably, the material of the solder sheet includes: a gold-nickel alloy; Preferably, the diameter of the welding sheet is equal to the bottom diameter of the electrode rod.

5. The welding method according to any one of claims 1-4, characterized in that, The thickness of the Kovar alloy sheet is 1-2.5 mm; Preferably, the diameter of the Kovar alloy sheet is equal to the bottom diameter of the electrode rod.

6. The welding method according to any one of claims 1-5, characterized in that, The wall thickness of the hollow welding sheet tube is 0.1-0.2 mm; Preferably, the hollow welding tube is made of a gold-nickel alloy; Preferably, the inner diameter of the hollow welding tube is equal to the bottom diameter of the electrode rod; Preferably, the hollow single-sided open sleeve is made of pure nickel; Preferably, the inner diameter of the hollow single-sided open sleeve is equal to the outer diameter of the hollow welded sheet cylinder; Preferably, the wall thickness of the hollow single-sided open sleeve is 0.2-1mm.

7. The welding method according to any one of claims 1-6, characterized in that, The degassing operation temperature is 200-300℃; Preferably, the absolute vacuum degree of the degassing is ≤0.001Pa.

8. The welding method according to any one of claims 1-7, characterized in that, The degassing time is 10-15 minutes.

9. The welding method according to any one of claims 1-8, characterized in that, The heating rate for hot isostatic pressing is 5-10℃ / min; Preferably, the holding temperature for hot isostatic pressing welding is 500-900℃; Preferably, the pressure of the hot isostatic pressing is 100-150 MPa.

10. The welding method according to any one of claims 1-9, characterized in that, The heat and pressure holding time for the hot isostatic pressing welding is 12-14 hours.

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