Hot-end anti-oxidation vacuum electrode and preparation method and application thereof

Abstract

The invention provides a hot-end anti-oxidation vacuum electrode and a preparation method and application thereof. Comprising an electrode bar and a pore plate nested on the electrode bar, the nested position of the pore plate and the electrode bar is covered with a composite sealing layer, and the composite sealing layer comprises a ceramic sealing layer and a colloid sealing layer; the ceramic sealing layer is used for filling a gap of the through hole of the pore plate and covering the electrode bar and the pore plate at the nested part; the colloid sealing layer is coated on the outer surface of the ceramic sealing layer; the electrode bar is divided into a first part and a second part by the pore plate, the first part is provided with a cold end connector, the second part is provided with a hot end connector, and an anti-oxidation coating is arranged on a bar body of the second part of the electrode bar. The hot-end anti-oxidation vacuum electrode has excellent temperature resistance, sealing performance and insulating performance, and can still meet the requirements of the sealing performance and the insulating performance even if the electrode is used under a high-temperature condition for a long time.

Description

Technical Field

[0001] The invention belongs to the field of optoelectronic manufacturing, and in particular relates to a hot-end oxidation-resistant vacuum electrode and a preparation method and application thereof. Background Art

[0002] In the photovoltaic industry, semiconductor and other new energy fields, the production process of cells and chips cannot be separated from the vacuum environment, and most of them are high-temperature vacuum equipment. The transmission of precision signals such as pressure and temperature inside the vacuum equipment and electrode signals needs to be transmitted to the atmosphere through lead wires. For the use of these components in a vacuum environment, in order to prevent the problem of air leakage and foreign matter entering and exiting the components, they need to be strictly sealed.

[0003] There are two main types of existing vacuum electrode joints. The one with high temperature resistance uses glass sintering to seal the end, but the manufacturing process requires high temperature sintering conditions of >600℃, which has high manufacturing costs and is often used in vacuum environments above 300℃. The other type is sealed by organic glue bonding, but the elasticity of the organic glue causes the vacuum electrode joint to shake, resulting in poor sealing effect.

[0004] Therefore, there is an urgent need to design a hot-end oxidation-resistant vacuum electrode with low manufacturing cost and excellent sealing performance. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a hot end anti-oxidation vacuum electrode and its preparation method and application. The hot end anti-oxidation vacuum electrode provided by the present invention has the following advantages: 1) excellent temperature resistance, the overall temperature resistance can reach above 350°C, and its hot end joint can withstand high temperatures of 600°C; 2) excellent sealing performance, helium test ≤10 -9 Pam 3 / s; 3) Excellent insulation performance, the insulation resistance between the electrode rod and the orifice plate is ≥500MΩ. In summary, the hot end oxidation-resistant vacuum electrode can still meet the requirements of sealing and insulation performance under long-term use under high temperature conditions.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a hot-end anti-oxidation vacuum electrode, comprising an electrode rod, and a perforated plate nested on the electrode rod, wherein the nesting position of the perforated plate and the electrode rod is covered with a composite sealing layer, wherein the composite sealing layer comprises a ceramic sealing layer and a colloid sealing layer; the ceramic sealing layer is used to fill the gap between the electrode rod and the perforated plate, and to cover at least part of the electrode rod and the perforated plate at the nesting position; the colloid sealing layer is coated on the outer surface of the ceramic sealing layer.

[0008] The orifice plate divides the electrode rod into a first part and a second part, wherein the first part has a cold end joint and a first rod body, and the second part has a hot end joint and a second rod body, the first rod body is connected to the second rod body, the cold end joint is arranged at an end of the first rod body away from the hot end joint, and the hot end joint is arranged at an end of the second rod body away from the cold end joint; wherein the outer surface of the second rod body is provided with an anti-oxidation coating.

[0009] In the hot-end anti-oxidation vacuum electrode provided by the present invention, the ceramic sealing layer serves as the initial seal and can play a fixing role, and the external colloid sealing layer cooperates with each other, which not only has a low manufacturing cost, but also can further improve the sealing effect. If only the colloid sealing method is used, deformation will occur during the installation, vacuuming and vacuum release processes; if only the ceramic sealing method is used, the required sealing performance cannot be achieved. By filling the gap between the electrode rod and the orifice plate with a ceramic sealing layer, the insulation resistance between the electrode rod and the orifice plate can be increased, thereby having better insulation performance. Combining the above-mentioned seals, the hot-end anti-oxidation vacuum electrode has the following advantages: 1) Excellent temperature resistance, the overall temperature resistance can reach above 350°C, and its hot-end joint can withstand high temperatures of 600°C; 2) Excellent sealing performance, helium inspection ≤10 -9 Pam 3 / s; 3) Excellent insulation performance, the insulation resistance between the electrode rod and the orifice plate is ≥500MΩ. In summary, the hot end oxidation-resistant vacuum electrode can still meet the requirements of sealing and insulation performance under long-term use under high temperature conditions.

[0010] It should be noted that the material of the electrode rod may be copper or the like, and the material of the orifice plate may be stainless steel, such as 304 stainless steel or 316 stainless steel or the like.

[0011] It should be noted that the cold end connector is a connector connected to an external data line and is used to transmit temperature data to the outside; the hot end connector is a connector connected to an electrode in the furnace and is used to collect the temperature in the furnace.

[0012] Preferably, the slurry of the ceramic sealing layer comprises the following components in parts by weight:

[0013] 50-80 parts of inorganic powder, for example, 50 parts, 60 parts, 70 parts or 80 parts, etc., 20-50 parts of inorganic binder, for example, 20 parts, 30 parts, 40 parts or 50 parts, etc., 0.1-10 parts of coagulant, for example, 0.1 parts, 1 parts, 5 parts or 10 parts, etc.

[0014] In the present invention, the synergistic combination of the components in the above ratio is helpful to enable the ceramic sealing layer to fully exert the effect of low-temperature curing.

[0015] Preferably, the inorganic powder includes aluminum oxide and / or silicon oxide.

[0016] Preferably, the inorganic binder includes any one of aluminum dihydrogen phosphate, sodium water glass or potassium water glass, or a combination of at least two thereof.

[0017] Preferably, the coagulant includes an organic coagulant and / or an inorganic coagulant. Exemplarily, the organic coagulant may be, for example, calcium formate, ammonium formate, triethanolamine or glyoxal, and the inorganic coagulant may be, for example, calcium fluoride, sodium chloride, sodium sulfate, aluminum sulfate, silicon phosphate, sodium silicate or sodium metasilicate.

[0018] Preferably, the material of the gelatin sealing layer includes single-component room temperature vulcanized silicone rubber and / or two-component room temperature vulcanized silicone rubber.

[0019] In the present invention, the single-component room temperature vulcanized silicone rubber is composed of a base polymer (usually terminal hydroxyl polydimethylsiloxane, etc.), a crosslinking agent (such as methyltriacetoxysilane, etc.), a catalyst (generally an organic tin catalyst, etc.), and some fillers (such as fumed silica, etc.) and additives. The components are pre-mixed in a sealed package, but the crosslinking reaction is temporarily inhibited by an inhibitor, and the vulcanization reaction will not begin until it comes into contact with conditions such as moisture in the air. The two-component room temperature vulcanized silicone rubber contains two independently packaged components. Component A is mainly a polysiloxane base polymer containing active groups such as terminal hydroxyl groups or terminal vinyl groups, as well as fillers and additives, and component B is a mixed system of a crosslinking agent (such as tetraethyl orthosilicate, etc.) and a catalyst (such as dibutyltin dilaurate, etc.). When used, component A and component B need to be mixed in a certain proportion before the vulcanization reaction occurs.

[0020] Preferably, the working temperature of the gelatin sealing layer is 25-350°C, for example, it may be 25°C, 50°C, 100°C, 150°C, 200°C, 250°C, 300°C or 350°C.

[0021] In the present invention, the colloid sealing layer obtained by using the above-mentioned material can work at the above-mentioned temperature for a long time, which is beneficial to improving the sealing performance and making the output signal in the electrode more stable.

[0022] Preferably, the thickness of the gelatin sealing layer is 30-50 μm, for example, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm.

[0023] Preferably, the thickness of the anti-oxidation coating is 50-100 μm, for example, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm.

[0024] In the present invention, an anti-oxidation coating with a suitable thickness is beneficial to improving the electrode's ability to resist oxygen corrosion at high temperatures.

[0025] Preferably, the material of the anti-oxidation coating includes any one of oxide, silicide or aluminide, or a combination of at least two of them.

[0026] Preferably, the oxide includes any one of aluminum oxide, silicon dioxide, zirconium oxide, titanium oxide or magnesium oxide, or a combination of at least two thereof.

[0027] Preferably, the silicide includes any one of molybdenum silicide, chromium silicide, titanium silicide or zirconium silicide, or a combination of at least two thereof.

[0028] Preferably, the aluminide includes any one of nickel aluminum, iron aluminum, cobalt aluminum or chromium aluminum, or a combination of at least two thereof.

[0029] In a second aspect, the present invention provides a method for preparing the hot end anti-oxidation vacuum electrode as described in the first aspect, the preparation method comprising the following steps:

[0030] (a) A jig is provided, and the orifice plate and the electrode rod are positioned by the jig.

[0031] (b) adding a ceramic sealing layer slurry to the gap between the orifice plate and the electrode rod, and then performing a heat treatment so that the formed ceramic sealing layer fills the through-hole gap of the orifice plate and covers the electrode rod and the orifice plate at the nesting position.

[0032] (c) coating a colloid sealing layer on the outer surface of the ceramic sealing layer, and then coating an anti-oxidation coating on the second part of the electrode rod having the hot end joint, and then performing heat treatment to obtain the hot end anti-oxidation vacuum electrode.

[0033] The preparation method provided by the invention has simple and rapid process, low cost and good development potential.

[0034] Preferably, the jig in step (a) has a groove, a blocking piece is provided at the opening of the groove, and a through hole is provided at the center of the groove, passing through the jig.

[0035] Preferably, in step (a), the electrode rod passes through the orifice plate, the blocking sheet and the fixture.

[0036] Preferably, after the slurry of the ceramic sealing layer is added in step (b), curing and demoulding are first performed, and then the heat treatment in step (b) is performed.

[0037] In the present invention, the purpose of curing and demoulding is to remove the jig.

[0038] Preferably, the heat treatment in step (b) comprises primary heat treatment, secondary heat treatment and tertiary heat treatment performed sequentially.

[0039] Preferably, the temperature of the primary heat treatment is 100-140°C, for example, 100°C, 110°C, 120°C, 130°C or 140°C, etc., and the time is 0.5-1.5h, for example, 0.5h, 1h or 1.5h, etc.

[0040] Preferably, the temperature of the secondary heat treatment is 140-160°C, for example, 140°C, 145°C, 150°C, 155°C or 160°C, etc., and the time is 0.5-1.5h, for example, 0.5h, 1h or 1.5h, etc.

[0041] Preferably, the temperature of the tertiary heat treatment is 160-200°C, such as 160°C, 170°C, 180°C, 190°C or 200°C, etc., and the time is 0.2-1h, such as 0.2h, 0.5h or 1h, etc.

[0042] In the present invention, a multi-stage heat treatment method is adopted, which not only makes the formed ceramic sealing layer uniform and dense, but also requires low temperature and low energy consumption, thereby greatly reducing the manufacturing cost.

[0043] Preferably, the method for preparing the slurry of the ceramic sealing layer in step (b) comprises the following steps:

[0044] The inorganic powder and the coagulant are mixed, and then an inorganic binder is added and solidified to obtain the slurry of the ceramic sealing layer.

[0045] Preferably, the inorganic binder is added with stirring.

[0046] Preferably, the mixing method is dry mixing, and the dry mixing time is 1-3 minutes, for example, 1 minute, 2 minutes or 3 minutes.

[0047] Preferably, the stirring time is 1-3 min, for example, 1 min, 2 min or 3 min.

[0048] Preferably, the solidification atmosphere is an air atmosphere.

[0049] It should be noted that the solidified slurry can be placed for 7 days without contact with air and can still be used after 7 days.

[0050] Preferably, the coating method of the colloid sealing layer in step (c) comprises:

[0051] The hot end side outer surface of the ceramic sealing layer is coated with a colloid sealing layer, and after solidification, the cold end side outer surface of the ceramic sealing layer is coated with a colloid sealing layer. Exemplarily, the coating method includes a spin coating method and the like.

[0052] Preferably, the coating method of the anti-oxidation coating in step (c) includes any one of a dip coating method, a spray coating method or a vapor deposition method. Exemplarily, the vapor deposition method may be a chemical vapor deposition method or a physical vapor deposition method.

[0053] Preferably, the temperature of the heat treatment in step (c) is 80-120°C, for example, 80°C, 90°C, 100°C, 110°C or 120°C, etc., and the time is 0.5-1.5h, for example, 0.5h, 1h or 1.5h, etc.

[0054] In a third aspect, the present invention provides a use of the hot-end anti-oxidation vacuum electrode as described in the first aspect in a vacuum device.

[0055] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The hot end anti-oxidation vacuum electrode provided by the present invention has the following advantages: 1) excellent temperature resistance, the overall temperature resistance can reach above 350°C, and the hot end joint can withstand a high temperature of 600°C; 2) excellent sealing performance, helium test ≤10 -9 Pam 3 / s; 3) Excellent insulation performance, the insulation resistance between the electrode rod and the orifice plate is ≥500MΩ. In summary, the hot end oxidation-resistant vacuum electrode can still meet the requirements of sealing and insulation performance under long-term use under high temperature conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 This is a schematic structural diagram of the hot-end anti-oxidation vacuum electrode provided in Example 1 of the present invention.

[0059] Figure 2 This is a process flow chart provided for Example 1 of the present invention.

[0060] Figure 3 This is a schematic diagram of the structure after step (1) in the preparation method provided in Example 1 of the present invention.

[0061] Figure 4 This is a schematic diagram of the structure after step (2) in the preparation method provided in Example 1 of the present invention.

[0062] Figure 5 This is a schematic diagram of the structure after step (3) in the preparation method provided in Example 1 of the present invention.

[0063] Figure 6This is a schematic diagram of the structure after step (4) in the preparation method provided in Example 1 of the present invention.

[0064] Among them, 1-electrode rod; 11-first rod body; 12-second rod body; 2-orifice plate; 3-ceramic sealing layer; 4-colloid sealing layer; 41-colloid sealing layer on the hot end side; 42-colloid sealing layer on the cold end side; 5-anti-oxidation coating; 6-hot end joint; 7-cold end joint; 8-jig; 9-blocking piece. DETAILED DESCRIPTION

[0065] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0066] Example 1

[0067] This embodiment provides a hot end anti-oxidation vacuum electrode, and its structural schematic diagram is as follows: Figure 1 As shown, it includes an electrode rod 1 and a perforated plate 2 nested on the electrode rod 1, and the nesting position of the perforated plate 2 and the electrode rod 1 is covered with a composite sealing layer, and the composite sealing layer includes a ceramic sealing layer 3 and a gelatin sealing layer 4; the ceramic sealing layer 3 is used to fill the gap between the electrode rod 1 and the perforated plate 2, and cover at least part of the electrode rod 1 and the perforated plate 2 at the nesting position; the gelatin sealing layer 4 is coated on the outer surface of the ceramic sealing layer 3.

[0068] The orifice plate 2 divides the electrode rod 1 into a first part and a second part, wherein the first part has a cold end joint 7 and a first rod body 11, and the second part has a hot end joint 6 and a second rod body 12, the first rod body 11 is connected to the second rod body 12, the cold end joint 7 is arranged at an end of the first rod body 11 away from the hot end joint 6, and the hot end joint 6 is arranged at an end of the second rod body 12 away from the cold end joint 7; wherein the outer surface of the second rod body 12 is provided with an anti-oxidation coating 5.

[0069] The slurry of the ceramic sealing layer 3 includes the following components in parts by weight:

[0070] 65 parts of inorganic powder, 35 parts of inorganic binder, 5 parts of coagulant; the inorganic powder is alumina, the inorganic binder is sodium water glass, the coagulant is an inorganic coagulant, and the inorganic coagulant is silicon phosphate.

[0071] The material of the colloid sealing layer 4 is single-component room temperature vulcanized silicone rubber, and the thickness is 40 μm.

[0072] The material of the anti-oxidation coating 5 is oxide, the oxide is aluminum oxide, and the thickness is 50 μm.

[0073] This embodiment also provides a method for preparing the hot end anti-oxidation vacuum electrode, and its process flow chart is as follows: Figure 2As shown, the preparation method comprises the following steps:

[0074] (1) A jig 8 is provided, wherein the jig 8 has a groove, a blocking piece 9 is provided at the opening of the groove, and a through hole is provided at the center of the groove, which passes through the jig 8; the orifice plate 2 and the electrode rod 1 are positioned by using the jig 8 so that the electrode rod 1 passes through the orifice plate 2, the blocking piece 9 and the jig 8.

[0075] The structural diagram after step (1) is as follows Figure 3 shown.

[0076] (2) The inorganic powder and the coagulant are dry-mixed for 1 minute, and then the inorganic binder is slowly added while stirring for 2 minutes. After stirring, it is exposed to air and solidified for about 30 minutes to obtain a slurry for the ceramic sealing layer.

[0077] The slurry of the ceramic sealing layer is added to the gap where the orifice plate and the electrode rod meet, and the mold is first cured and demolded, and then heat treated, so that the formed ceramic sealing layer fills the through-hole gap of the orifice plate and covers the electrode rod and orifice plate at the nesting position. Figure 4 A schematic diagram of the structure after step (2) is shown.

[0078] Among them, the heat treatment includes primary heat treatment, secondary heat treatment and tertiary heat treatment carried out in sequence. The temperature of the primary heat treatment is 120°C and the time is 1 hour. The temperature of the secondary heat treatment is 150°C and the time is 1 hour. The temperature of the tertiary heat treatment is 180°C and the time is 0.5 hour.

[0079] (3) With the hot end joint of the electrode rod facing upward, a gelatinous sealing layer is coated on the outer surface of the hot end side of the ceramic sealing layer by a spin coating method to form a gelatinous sealing layer on the hot end side. Figure 5 A schematic diagram of the structure after step (3) is shown.

[0080] (4) After the gelatinous sealing layer coated in step (3) solidifies, the electrode rod is turned over and the gelatinous sealing layer is coated on the outer surface of the cold end side of the ceramic sealing layer by a spin coating method, and then naturally solidifies to form a gelatinous sealing layer on the cold end side. Figure 6 A schematic diagram of the structure after step (4) is shown.

[0081] (5) An anti-oxidation coating is applied to the second part of the electrode rod having the hot end joint by artificial spraying, and after the surface is dried, a heat treatment is performed at 100° C. for 1 h to obtain a hot end anti-oxidation vacuum electrode.

[0082] Example 2

[0083] The present embodiment provides a hot-end anti-oxidation vacuum electrode, comprising an electrode rod and a perforated plate nested on the electrode rod, wherein the nesting position of the perforated plate and the electrode rod is covered with a composite sealing layer, wherein the composite sealing layer comprises a ceramic sealing layer and a colloid sealing layer; the ceramic sealing layer is used to fill the gap between the electrode rod and the perforated plate, and to cover at least part of the electrode rod and the perforated plate at the nesting position; the colloid sealing layer is coated on the outer surface of the ceramic sealing layer.

[0084] The orifice plate divides the electrode rod into a first part and a second part, wherein the first part has a cold end joint and a first rod body, and the second part has a hot end joint and a second rod body, the first rod body is connected to the second rod body, the cold end joint is arranged at an end of the first rod body away from the hot end joint, and the hot end joint is arranged at an end of the second rod body away from the cold end joint; wherein the outer surface of the second rod body is provided with an anti-oxidation coating.

[0085] The slurry of the ceramic sealing layer includes the following components in parts by weight:

[0086] 50 parts of inorganic powder, 20 parts of inorganic binder, and 0.1 parts of coagulant; the inorganic powder is silicon oxide, the inorganic binder is aluminum dihydrogen phosphate, the coagulant includes an organic coagulant and an inorganic coagulant, the organic coagulant is glyoxal, and the inorganic coagulant is sodium metasilicate.

[0087] The material of the colloid sealing layer is two-component room temperature vulcanized silicone rubber with a thickness of 30 μm.

[0088] The material of the anti-oxidation coating is oxide, the oxide is silicon dioxide, and the thickness is 60 μm.

[0089] This embodiment also provides a method for preparing the hot end anti-oxidation vacuum electrode, the preparation method comprising the following steps:

[0090] (1) A jig is provided, wherein the jig has a groove, a material blocking piece is provided at the opening of the groove, and a through hole is provided at the center of the groove, which passes through the jig; the orifice plate and the electrode rod are positioned by using the jig so that the electrode rod passes through the orifice plate, the material blocking piece and the jig.

[0091] (2) The inorganic powder and the coagulant are dry-mixed for 2 minutes, and then the inorganic binder is slowly added while stirring for 1 minute. After stirring, it is exposed to air and solidified for about 30 minutes to obtain a slurry for the ceramic sealing layer.

[0092] The slurry of the ceramic sealing layer is added to the gap where the orifice plate and the electrode rod meet, and the mold is first cured and demolded, and then heat treated, so that the formed ceramic sealing layer fills the through-hole gap of the orifice plate and covers the electrode rod and orifice plate at the nesting position.

[0093] Among them, the heat treatment includes primary heat treatment, secondary heat treatment and tertiary heat treatment carried out in sequence. The temperature of the primary heat treatment is 100°C and the time is 1.5 hours, the temperature of the secondary heat treatment is 140°C and the time is 1.5 hours, and the temperature of the tertiary heat treatment is 160°C and the time is 1 hour.

[0094] (3) With the hot end joint of the electrode rod facing upward, a colloid sealing layer is coated on the outer surface of the hot end side of the ceramic sealing layer by a spin coating method.

[0095] (4) After the gelatinous sealing layer applied in step (3) solidifies, the electrode rod is turned over and the gelatinous sealing layer is applied to the outer surface of the cold end side of the ceramic sealing layer by a spin coating method, and then solidified naturally.

[0096] (5) An anti-oxidation coating is applied to the second part of the electrode rod having the hot end joint by artificial spraying, and after the surface is dried, a heat treatment is performed at 80° C. for 1.5 h to obtain a hot end anti-oxidation vacuum electrode.

[0097] Example 3

[0098] The present embodiment provides a hot-end anti-oxidation vacuum electrode, comprising an electrode rod and a perforated plate nested on the electrode rod, wherein the nesting position of the perforated plate and the electrode rod is covered with a composite sealing layer, wherein the composite sealing layer comprises a ceramic sealing layer and a colloid sealing layer; the ceramic sealing layer is used to fill the gap between the electrode rod and the perforated plate, and to cover at least part of the electrode rod and the perforated plate at the nesting position; the colloid sealing layer is coated on the outer surface of the ceramic sealing layer.

[0099] The orifice plate divides the electrode rod into a first part and a second part, wherein the first part has a cold end joint and a first rod body, and the second part has a hot end joint and a second rod body, the first rod body is connected to the second rod body, the cold end joint is arranged at an end of the first rod body away from the hot end joint, and the hot end joint is arranged at an end of the second rod body away from the cold end joint; wherein the outer surface of the second rod body is provided with an anti-oxidation coating.

[0100] The slurry of the ceramic sealing layer includes the following components in parts by weight:

[0101] 80 parts of inorganic powder, 50 parts of inorganic binder, and 10 parts of coagulant; the inorganic powder is silicon oxide, the inorganic binder is aluminum dihydrogen phosphate, the coagulant is an inorganic coagulant, and the inorganic coagulant is sodium metasilicate.

[0102] The material of the colloid sealing layer is single-component room temperature vulcanized silicone rubber with a thickness of 40 μm.

[0103] The material of the anti-oxidation coating is oxide, the oxide is molybdenum disilicide, and the thickness is 60 μm.

[0104] This embodiment also provides a method for preparing the hot end anti-oxidation vacuum electrode, the preparation method comprising the following steps:

[0105] (1) A jig is provided, wherein the jig has a groove, a material blocking piece is provided at the opening of the groove, and a through hole is provided at the center of the groove, which passes through the jig; the orifice plate and the electrode rod are positioned by using the jig so that the electrode rod passes through the orifice plate, the material blocking piece and the jig.

[0106] (2) The inorganic powder and the coagulant are dry-mixed for 3 minutes, and then the inorganic binder is slowly added while stirring for 3 minutes. After stirring, it is exposed to air and solidified for about 30 minutes to obtain a slurry for the ceramic sealing layer.

[0107] The slurry of the ceramic sealing layer is added to the gap where the orifice plate and the electrode rod meet, and the mold is first cured and demolded, and then heat treated, so that the formed ceramic sealing layer fills the through-hole gap of the orifice plate and covers the electrode rod and orifice plate at the nesting position.

[0108] Among them, the heat treatment includes primary heat treatment, secondary heat treatment and tertiary heat treatment carried out in sequence. The temperature of the primary heat treatment is 140°C and the time is 0.5h, the temperature of the secondary heat treatment is 160°C and the time is 0.5h, and the temperature of the tertiary heat treatment is 200°C and the time is 0.2h.

[0109] (3) With the hot end joint of the electrode rod facing upward, a colloid sealing layer is coated on the outer surface of the hot end side of the ceramic sealing layer by a spin coating method.

[0110] (4) After the gelatinous sealing layer applied in step (3) solidifies, the electrode rod is turned over and the gelatinous sealing layer is applied to the outer surface of the cold end side of the ceramic sealing layer by a spin coating method, and then solidified naturally.

[0111] (5) An anti-oxidation coating is applied to the second part of the electrode rod having the hot end joint by artificial spraying, and after the surface is dried, a heat treatment is performed at 120° C. for 0.5 h to obtain a hot end anti-oxidation vacuum electrode.

[0112] Example 4

[0113] The difference between this embodiment and embodiment 1 is that the slurry of the ceramic sealing layer does not contain organic coagulant and inorganic coagulant.

[0114] The rest of the structure, preparation method and parameters remain the same as those in Example 1.

[0115] Example 5

[0116] The difference between this embodiment and embodiment 1 is that the thickness of the colloid sealing layer is 30 μm.

[0117] The rest of the structure, preparation method and parameters remain the same as those in Example 1.

[0118] Example 6

[0119] The difference between this embodiment and embodiment 1 is that the thickness of the colloid sealing layer is 50 μm.

[0120] The rest of the structure, preparation method and parameters remain the same as those in Example 1.

[0121] Example 7

[0122] The difference between this embodiment and embodiment 1 is that the thickness of the anti-oxidation coating is 40 μm.

[0123] The rest of the structure, preparation method and parameters remain the same as those in Example 1.

[0124] Example 8

[0125] The difference between this embodiment and embodiment 1 is that the thickness of the anti-oxidation coating is 100 μm.

[0126] The rest of the structure, preparation method and parameters remain the same as those in Example 1.

[0127] Example 9

[0128] The difference between this embodiment and embodiment 1 is that the heat treatment in step (2) is a one-step heat treatment, that is, heating at 180° C. for only 2.5 h.

[0129] The rest of the structure, preparation method and parameters remain the same as those in Example 1.

[0130] Example 10

[0131] The difference between this embodiment and embodiment 1 is that the temperature of the third-stage heat treatment in step (2) is 250°C.

[0132] The rest of the structure, preparation method and parameters remain the same as those in Example 1.

[0133] Comparative Example 1

[0134] The difference between this comparative example and Example 1 is that no gelatin sealing layer is provided.

[0135] The rest of the structure, preparation method and parameters remain the same as those in Example 1.

[0136] Comparative Example 2

[0137] The difference between this comparative example and Example 1 is that the positions of the ceramic sealing layer and the colloid sealing layer are exchanged, that is, the colloid sealing layer is coated first, and then the ceramic sealing layer is coated.

[0138] The rest of the structure, preparation method and parameters remain the same as those in Example 1.

[0139] Comparative Example 3

[0140] The difference between this comparative example and Example 1 is that no anti-oxidation coating is provided.

[0141] The rest of the structure, preparation method and parameters remain the same as those in Example 1.

[0142] Performance Testing

[0143] The hot-end anti-oxidation vacuum electrodes provided in the above-mentioned embodiments and comparative examples were tested for sealing performance, insulation performance and temperature resistance performance.

[0144] The testing method for sealing performance is: using a helium mass spectrometer leak detector for detection.

[0145] The test method for insulation performance is: using a voltage resistance tester for testing.

[0146] The test method for temperature resistance is: using a thermogravimetric analyzer and an oven, that is, after the product is prepared, it is aged in an oven and then the sealing performance is tested.

[0147] The above test results are shown in Table 1.

[0148] Table 1

[0149]

[0150]

[0151] analyze:

[0152] The hot end anti-oxidation vacuum electrode provided by the present invention has the following advantages: 1) excellent temperature resistance, the overall temperature resistance can reach above 350°C, and the hot end joint can withstand a high temperature of 600°C; 2) excellent sealing performance, helium test ≤10 -9 Pam 3 / s; 3) Excellent insulation performance, the insulation resistance between the electrode rod and the orifice plate is ≥500MΩ. In summary, the hot end oxidation-resistant vacuum electrode can still meet the requirements of sealing and insulation performance under long-term use under high temperature conditions.

[0153] From the comparison between Example 1 and Example 4, it can be seen that if the slurry of the ceramic sealing layer does not contain organic coagulant and inorganic coagulant, it is not conducive to the curing and densification of the sealing layer.

[0154] From the comparison between Example 1 and Examples 5-6, it can be seen that if the thickness of the colloid sealing layer is too thin, it is not conducive to improving the sealing performance. If the thickness of the colloid sealing layer is too thick, it is not conducive to installation.

[0155] From the comparison between Example 1 and Examples 7-8, it can be seen that if the thickness of the anti-oxidation coating is too thin, it is not conducive to the anti-oxidation ability of the electrode. If the thickness of the anti-oxidation coating is too thick, it is not conducive to the adhesion performance between the coating and the electrode and is easy to fall off.

[0156] From the comparison between Example 1 and Examples 9-10, it can be seen that if the heat treatment method is a one-step heat treatment, the slurry layer will crack, which is not conducive to the sealing performance. If the temperature of the three-stage heat treatment is too high, the electrode will be at risk of oxidation.

[0157] The applicant declares that the present invention illustrates the process method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A hot end oxidation resistant vacuum electrode, characterized in that: It comprises an electrode rod, and a perforated plate embedded in the electrode rod, wherein the embedding position of the perforated plate and the electrode rod is covered with a composite sealing layer, wherein the composite sealing layer comprises a ceramic sealing layer and a colloid sealing layer; the ceramic sealing layer is used to fill the gap between the electrode rod and the perforated plate, and to cover at least part of the electrode rod and the perforated plate at the embedding position; the colloid sealing layer is coated on the outer surface of the ceramic sealing layer; The orifice plate divides the electrode rod into a first part and a second part, wherein the first part has a cold end joint and a first rod body, and the second part has a hot end joint and a second rod body, the first rod body is connected to the second rod body, the cold end joint is arranged at an end of the first rod body away from the hot end joint, and the hot end joint is arranged at an end of the second rod body away from the cold end joint; wherein the outer surface of the second rod body is provided with an anti-oxidation coating.

2. The hot end oxidation resistant vacuum electrode according to claim 1, characterized in that: The slurry of the ceramic sealing layer includes the following components in parts by weight: 50-80 parts of inorganic powder, 20-50 parts of inorganic binder, 0.1-10 parts of coagulant; Preferably, the inorganic powder comprises aluminum oxide and / or silicon oxide; Preferably, the inorganic binder comprises any one of aluminum dihydrogen phosphate, sodium water glass or potassium water glass, or a combination of at least two thereof; Preferably, the coagulant comprises an organic coagulant and / or an inorganic coagulant.

3. The hot end oxidation resistant vacuum electrode according to claim 1 or 2, characterized in that: The material of the colloid sealing layer includes single-component room temperature vulcanized silicone rubber and / or two-component room temperature vulcanized silicone rubber; Preferably, the working temperature of the gelatinous sealing layer is 25-350°C; Preferably, the gelatin sealing layer has a thickness of 30-50 μm.

4. The hot end oxidation resistant vacuum electrode according to any one of claims 1 to 3, characterized in that: The thickness of the anti-oxidation coating is 50-100 μm; Preferably, the material of the anti-oxidation coating includes any one of oxide, silicide or aluminide, or a combination of at least two of them.

5. A method for preparing a hot end oxidation-resistant vacuum electrode according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: (a) providing a jig, using the jig to position the orifice plate and the electrode rod; (b) adding a slurry of a ceramic sealing layer to the gap between the orifice plate and the electrode rod, and then performing a heat treatment so that the formed ceramic sealing layer fills the gap between the through holes of the orifice plate and covers the electrode rod and the orifice plate at the nesting position; (c) coating a colloid sealing layer on the outer surface of the ceramic sealing layer, and then coating an anti-oxidation coating on the second part of the electrode rod having the hot end joint, and then performing heat treatment to obtain the hot end anti-oxidation vacuum electrode.

6. The preparation method according to claim 5, characterized in that: The jig in step (a) has a groove, a blocking piece is provided at the opening of the groove, and a through hole is provided at the center of the groove, passing through the jig; Preferably, in step (a), the electrode rod passes through the orifice plate, the material blocking sheet and the fixture; Preferably, after the slurry of the ceramic sealing layer is added in step (b), curing and demoulding are first performed, and then the heat treatment in step (b) is performed; Preferably, the heat treatment in step (b) comprises a primary heat treatment, a secondary heat treatment and a tertiary heat treatment performed sequentially; Preferably, the temperature of the primary heat treatment is 100-140°C and the time is 0.5-1.5h; Preferably, the temperature of the secondary heat treatment is 140-160°C and the time is 0.5-1.5h; Preferably, the temperature of the three-stage heat treatment is 160-200° C. and the time is 0.2-1 h.

7. The preparation method according to claim 5 or 6, characterized in that: The method for preparing the slurry of the ceramic sealing layer in step (b) comprises the following steps: The inorganic powder and the coagulant are mixed, and then an inorganic binder is added and solidified to obtain the slurry of the ceramic sealing layer; Preferably, the inorganic binder is added with stirring; Preferably, the solidification atmosphere is an air atmosphere.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The coating method of the colloid sealing layer in step (c) comprises: The outer surface of the hot end side of the ceramic sealing layer is coated with a colloid sealing layer, and after solidification, the outer surface of the cold end side of the ceramic sealing layer is coated with a colloid sealing layer.

9. The preparation method according to any one of claims 5 to 8, characterized in that: The coating method of the anti-oxidation coating in step (c) includes any one of a dip coating method, a spray coating method or a vapor deposition method; Preferably, the heat treatment in step (c) is carried out at a temperature of 80-120° C. and for a time of 0.5-1.5 h.

10. Use of the hot end anti-oxidation vacuum electrode according to any one of claims 1 to 4 in vacuum equipment.

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