CN117820005A - Flat seal structure assembly of flat seal structure porcelain seal piece and high-precision sealing method thereof - Google Patents

Abstract

The application relates to the technical field of ceramic packaging bodies, and discloses a high-precision sealing method of a flat-sealing structure ceramic packaging piece, which comprises the following method steps: s1, firstly plating T i films on the upper end face and the lower end face of ceramic to realize metallization, wherein a Ti film is used as a base film for ceramic metallization; s2, heating and insulating the plated porcelain piece in a vacuum atmosphere environment, and improving the binding force of the T i film layer and the ceramic; s3, plating Cu films and Ag films on the upper end face and the lower end face of the porcelain piece in sequence; s4, after the film is covered, the ceramic and the metal piece are clamped and fixed by the special flat sealing structure component and then heated and kept warm for a period of time in a vacuum furnace. The Cu and Ag metal films with the grade of mu m are plated after the ceramic is plated with the T i film, so that the Cu and Ag metal films are used as a reaction film layer for transitional liquid phase diffusion welding, the variation of the component in the height direction before and after sealing is obviously improved, the high-precision sealing effect is realized, and the control consistency of the electrode spacing of the porcelain sealing piece of the flat sealing structure of the vacuum electronic device is improved.

Description

Flat seal structure component of flat seal structure porcelain seal and high-precision sealing method thereof

Technical Field

The invention relates to the technical field of ceramic packaging bodies, in particular to a flat sealing structure component of a flat sealing structure ceramic sealing piece and a high-precision sealing method thereof.

Background technique

Vacuum electronic devices are widely used in broadcasting, communications, television, radar, navigation, medical diagnosis and other fields. With the improvement of the performance of the whole system, higher requirements are placed on the performance of vacuum electronic devices, and it is necessary to achieve improvement in indicators such as high efficiency, long life and high power. Ceramic and metal sealing structures are insulating structures inside vacuum electronic devices. On the premise of meeting the voltage resistance of each pole, it is necessary to ensure that the distance between each pole meets the design requirements and that the electron trajectory meets the design requirements to ensure indicators such as power and efficiency. The height dimension of the existing flat-seal structure porcelain seal changes greatly before and after sealing, which has a great impact on the shape of electron injection in the electron gun. Due to the existence of these problems, the further improvement of the efficiency and power of vacuum electronic devices is hindered.

After technical investigation and process research, it was found that the use of advanced thin film metallization technology, the rational selection of film layer types and the combination of appropriate heat treatment temperatures can achieve high-precision connection of flat-seal structure porcelain seals.

Summary of the invention

In view of the shortcomings of the prior art, the present invention provides a flat-seal structure component of a flat-seal structure porcelain seal and a high-precision sealing method thereof, with the aim of solving the problem of excessive change in height direction before and after sealing, improving the conformity between actual sealing dimensions and design values, improving the consistency of inter-electrode spacing and pressure-resistant reliability of vacuum electronic devices, and helping to improve indicators such as overall tube efficiency and power.

To achieve the above objectives, the present invention is implemented through the following technical solutions: A high-precision sealing method for a flat-seal structure porcelain seal comprises the following method steps:

S1, firstly coating the upper and lower end surfaces of the ceramic with a Ti film to achieve metallization, wherein the Ti film serves as a base film for ceramic metallization;

S2, heating and heat-insulating the plated ceramic parts in a vacuum atmosphere to enhance the bonding strength between the Ti film layer and the ceramic, prevent the film layer from peeling and falling off, and meet the subsequent sealing strength requirements;

S3, coating the upper and lower end surfaces of the ceramic component with a Cu film and an Ag film in sequence;

S4. After coating, the ceramic and metal parts are clamped and fixed in a special flat sealing structure assembly, and then heated and kept warm for a period of time in a vacuum furnace, so that the atoms in the Cu film and the Ag film diffuse with each other to form a silver-copper eutectic alloy solder.

Preferably, in the step S1, the coating thickness of the Ti film on the upper and lower end surfaces of the ceramic is 2±0.2 μm.

Preferably, in step S2, the heating temperature of the ceramic piece in a vacuum atmosphere is 700° C., and the holding time is 5 minutes.

Preferably, in the step S3, the plating thickness of the Cu film is 1±0.2 μm, and the plating thickness of the Ag film is 2±0.2 μm.

Preferably, in the step S4, the vacuum furnace is heated to 800°C and kept warm for 10 min, the heating rate is ≤500°C/h, the cooling rate is ≤300°C/h, and the vacuum degree is controlled to be better than 1×10-3Pa.

The flat seal structure component of the flat seal structure porcelain seal comprises an upper mold and a lower mold, a gun housing component is installed between the upper mold and the lower mold, a screw is installed on one side of the lower mold, the top end of the screw passes through one side of the upper mold and extends out a part, and a nut is threadedly connected on the outer wall of the screw.

The present invention provides a flat seal structure component of a flat seal structure porcelain seal and a high-precision sealing method thereof. It has the following beneficial effects:

The present invention plates Cu and Ag metal films of μm level on ceramics after metallization by Ti film as reaction film layers for transitional liquid phase diffusion welding. The assembled ceramic and metal sealing components are kept at 800°C for 10 minutes in a vacuum atmosphere. Atoms in the Cu film and the Ag film diffuse to form eutectic alloy solder, thus realizing transitional liquid phase diffusion welding. The change in height direction before and after sealing of the components is significantly improved, and the change in height direction of a single weld is reduced from the original 20 to 30 μm to 4 μm, thereby realizing a high-precision sealing effect and improving the control consistency of the inter-electrode spacing of porcelain seals of a flat-sealed structure of vacuum electronic devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the assembly of a flat seal structure assembly of the present invention;

FIG. 2 is a schematic diagram of a ceramic component with a coating layer according to the present invention.

Among them, 1. screw; 2. nut; 3. upper mold; 4. lower mold; 5. gun housing assembly.

Detailed ways

The following will be combined with the drawings of the present invention specification to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Please refer to Figures 1-2, the present invention provides a high-precision sealing method for a flat-seal structure porcelain seal, including the following method steps:

S1. First, Ti film is plated on the upper and lower end surfaces of the ceramic to achieve metallization. The Ti film is used as the base film for ceramic metallization and is very critical to ensure the sealing quality of the ceramic sealing component. In this step, the plating thickness of the Ti film on the upper and lower end surfaces of the ceramic is 2±0.2μm;

S2, heating and heat-insulating the plated ceramic piece in a vacuum atmosphere to enhance the bonding strength between the Ti film layer and the ceramic, prevent the film layer from peeling and falling off, and meet the subsequent sealing strength requirements. In this step, the heating temperature of the ceramic piece in a vacuum atmosphere is 700° C., and the heat preservation time is 5 minutes;

S3, as shown in FIG. 2, Cu film and Ag film are plated on the upper and lower end surfaces of the ceramic component in sequence. In this step, the plating thickness of the Cu film is 1±0.2 μm, and the plating thickness of the Ag film is 2±0.2 μm;

S4. Please refer to Figure 1. After the coating, the ceramic and metal parts are clamped and fixed in a special flat sealing structure component, and then heated and kept warm for a period of time in a vacuum furnace, so that the atoms in the Cu film and the Ag film diffuse with each other to form a silver-copper eutectic alloy solder. In this step, the vacuum furnace is heated to 800°C and kept warm for 10 minutes, the heating rate is ≤500°C/h, the cooling rate is ≤300°C/h, and the vacuum degree is controlled to be better than 1×10-3Pa.

Furthermore, an embodiment of the present invention also provides a flat-seal structural component of a flat-seal structural porcelain seal, which is applied to the high-precision sealing method of the flat-seal structural porcelain seal mentioned in this embodiment. The structural component includes an upper mold 3 and a lower mold 4, a gun housing component 5 is installed between the upper mold 3 and the lower mold 4, a screw 1 is installed on one side of the lower mold 4, the top of the screw 1 passes through one side of the upper mold 3 and extends a part, and a nut 2 is threadedly connected on the outer wall of the screw 1, wherein the nut 2 is located on the upper part of one side of the upper mold 3 and is connected to the screw 1. Through this structure, the ceramic and metal parts can be clamped and fixed after coating, and then heated and kept warm in a vacuum furnace.

The screw 1 is made of kovar material with a coefficient of expansion close to that of ceramics, ensuring that the ceramic parts and metal parts can be in close contact at high temperatures; the upper and lower fastening molds are made of stainless steel, and the thickness of the upper mold 3 reaches 5-6mm, relying on the mold's own weight to fully squeeze the liquid silver-copper eutectic alloy formed by the Cu film and Ag film at high temperatures, further reducing the change in the height direction after sealing;

Furthermore, the gun housing assembly 5 is an important component of the vacuum electronic device, and its main function is to support and control the spacing between the metal parts, and at the same time achieve the pressure resistance between the poles through the ceramics in the middle, ensuring that the product working state meets the design requirements.

The present invention will be further explained below in conjunction with specific embodiments:

Embodiment 1:

The high-precision sealing method of a flat seal structure porcelain seal comprises the following steps:

S1. First, Ti film is plated on the upper and lower end surfaces of the ceramic to achieve metallization. In this step, the plating thickness of the Ti film on the upper and lower end surfaces of the ceramic is 1.8 μm;

S2, heating and heat-insulating the plated porcelain piece in a vacuum atmosphere. In this step, the heating temperature of the porcelain piece in the vacuum atmosphere is 700° C., and the heat-insulating time is 5 minutes;

S3, as shown in FIG. 2, Cu film and Ag film are plated on the upper and lower end surfaces of the ceramic component in sequence. In this step, the plating thickness of the Cu film is 0.8 μm, and the plating thickness of the Ag film is 1.8 μm;

S4. After coating, the ceramic and metal parts are clamped and fixed in a special flat sealing structure assembly, and then heated and kept warm for a period of time in a vacuum furnace, so that the atoms in the Cu film and the Ag film diffuse with each other to form a silver-copper eutectic alloy solder. In this step, the vacuum furnace is heated to 800°C and kept warm for 10 minutes, the heating rate is 460°C/h, the cooling rate is 260°C/h, and the vacuum degree is controlled to be better than 1×10-3Pa.

Embodiment 2:

The high-precision sealing method of a flat seal structure porcelain seal comprises the following steps:

S1. First, Ti film is plated on the upper and lower end surfaces of the ceramic to achieve metallization. In this step, the plating thickness of the Ti film on the upper and lower end surfaces of the ceramic is 2 μm;

S2, heating and heat-insulating the plated porcelain piece in a vacuum atmosphere. In this step, the heating temperature of the porcelain piece in the vacuum atmosphere is 700° C., and the heat-insulating time is 5 minutes;

S3, as shown in FIG. 2, Cu film and Ag film are plated on the upper and lower end surfaces of the ceramic component in sequence. In this step, the plating thickness of the Cu film is 1 μm, and the plating thickness of the Ag film is 2 μm;

S4. After coating, the ceramic and metal parts are clamped and fixed in a special flat sealing structure assembly, and then heated and kept warm for a period of time in a vacuum furnace, so that the atoms in the Cu film and the Ag film diffuse with each other to form a silver-copper eutectic alloy solder. In this step, the vacuum furnace is heated to 800°C and kept warm for 10 minutes, the heating rate is 480°C/h, the cooling rate is 280°C/h, and the vacuum degree is controlled to be better than 1×10-3Pa.

Embodiment three:

The high-precision sealing method of a flat seal structure porcelain seal comprises the following steps:

S1. First, Ti film is plated on the upper and lower end surfaces of the ceramic to achieve metallization. In this step, the plating thickness of the Ti film on the upper and lower end surfaces of the ceramic is 2.2 μm;

S2, heating and heat-insulating the plated porcelain piece in a vacuum atmosphere. In this step, the heating temperature of the porcelain piece in the vacuum atmosphere is 700° C., and the heat-insulating time is 5 minutes;

S3, referring to FIG. 2, the upper and lower end surfaces of the ceramic piece are plated with a Cu film and an Ag film in sequence. In this step, the plating thickness of the Cu film is 1.2 μm, and the plating thickness of the Ag film is 2.2 μm;

S4. After coating, the ceramic and metal parts are clamped and fixed in a special flat sealing structure assembly, and then heated and kept warm for a period of time in a vacuum furnace, so that the atoms in the Cu film and the Ag film diffuse with each other to form a silver-copper eutectic alloy solder. In this step, the vacuum furnace is heated to 800°C and kept warm for 10 minutes, with a heating rate of 500°C/h and a cooling rate of 300°C/h. The vacuum degree is controlled to be better than 1×10-3Pa.

Table 1: Parameter setting table for steps of Examples 1 to 3

The present invention plates Cu and Ag metal films of μm level on ceramic parts after metallization by Ti film as reaction film layers for transitional liquid phase diffusion welding. The assembled ceramic and metal sealing components are kept at 800°C for 10 minutes in a vacuum atmosphere, and atoms in the Cu film and the Ag film diffuse to form eutectic alloy solder, thus achieving transitional liquid phase diffusion welding.

This method significantly improves the height variation of the component before and after sealing. The height variation of a single weld is reduced from the original 20 to 30 μm to 4 μm, achieving a high-precision sealing effect and improving the consistency of control of the inter-electrode spacing of the flat-sealed porcelain seals of vacuum electronic devices.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims (6)

1. The high-precision sealing method of the porcelain seal piece with the flat seal structure is characterized by comprising the following steps of:

s1, firstly plating Ti films on the upper end face and the lower end face of the ceramic to realize metallization, wherein the Ti films are used as basic films for ceramic metallization;

s2, heating and preserving heat of the plated porcelain piece in a vacuum atmosphere environment, improving the bonding force of the Ti film layer and the ceramic, avoiding peeling and falling of the film layer, and meeting the requirement of subsequent sealing strength;

s3, plating Cu films and Ag films on the upper end face and the lower end face of the porcelain piece in sequence;

s4, after the film is covered, the ceramic and the metal piece are clamped and fixed by the special flat sealing structure component, and then are heated and kept warm for a period of time in a vacuum furnace, so that atoms in the Cu film and the Ag film are mutually diffused to form silver-copper eutectic alloy solder.

2. The high-precision sealing method of a flat-seal structured porcelain seal according to claim 1, wherein in the step S1, the plating thickness of the Ti films on the upper and lower end surfaces of the ceramic is 2±0.2 μm.

3. The high-precision sealing method of the flat-seal structured porcelain seal according to claim 1, wherein in the step S2, the heating temperature of the porcelain seal in a vacuum atmosphere environment is 700 ℃, and the heat preservation time is 5min.

4. The high precision sealing method of flat seal structure porcelain seal according to claim 1, wherein in the step S3, the plating thickness of Cu film is 1±0.2 μm, and the plating thickness of Ag film is 2±0.2 μm.

5. The high-precision sealing method of the flat-seal structured porcelain seal according to claim 1, wherein in the step S4, the vacuum furnace is heated to 800 ℃ for 10min, the heating rate is less than or equal to 500 ℃/h, the cooling rate is less than or equal to 300 ℃/h, and the vacuum degree control is better than 1X 10-3Pa.

6. The flat sealing structure component of the flat sealing structure porcelain sealing member is characterized by being applied to the high-precision sealing method of the flat sealing structure porcelain sealing member according to any one of claims 1 to 5, and comprises an upper die (3) and a lower die (4), wherein a gun shell component (5) is arranged between the upper die (3) and the lower die (4), a screw rod (1) is arranged on one side of the lower die (4), the top end of the screw rod (1) penetrates through one side of the upper die (3) and stretches out of one part, and a nut (2) is connected to the outer wall of the screw rod (1) in a threaded mode.