CN110776330A

CN110776330A - Brazing method of ceramic and metal

Info

Publication number: CN110776330A
Application number: CN201911268867.4A
Authority: CN
Inventors: 王蕾; 卢陆旺
Original assignee: Shenzhen Sibionics Technology Co Ltd
Current assignee: Shenzhen Sibionics Technology Co Ltd
Priority date: 2018-12-31
Filing date: 2019-12-11
Publication date: 2020-02-11
Also published as: CN109734469A; CN211522037U; CN110734298A; CN110776329A

Abstract

The present disclosure provides a method of brazing ceramic to metal, comprising: preparing ceramics to be welded and metals to be welded, and carrying out surface treatment on the ceramics to be welded so as to form the surfaces of the ceramics to be welded into smooth surfaces; carrying out metallization treatment on the surface of the ceramic to be welded to form an intermediate metal layer combined with the ceramic to be welded, wherein the thermal expansion coefficient of the ceramic to be welded is matched with that of the intermediate metal layer; and sequentially stacking the ceramics to be welded, the brazing metal and the metals to be welded for brazing, wherein the brazing metal is arranged between the middle metal layer and the metals to be welded, the brazing metal is melted by heating during brazing, the melted brazing metal infiltrates the middle metal layer and keeps a melting state for a preset time, so that a welding surface is formed on an interface between the brazing metal and the ceramics to be welded with the middle metal layer, and annealing and curing are carried out. According to the present disclosure, a method of brazing ceramic to metal capable of reducing thermal stress of an interface layer and improving the airtightness and shear strength of the interface layer can be provided.

Description

Brazing method of ceramic and metal

Technical Field

The present disclosure relates particularly to a method of brazing ceramic to metal.

Background

Ceramics are widely used in various fields as high-temperature structural materials because of their excellent biocompatibility, heat resistance, corrosion resistance, electrical insulation properties, and the like. However, in practical applications, in order to solve the problem of poor workability due to excessive hardness of the ceramic itself, it is necessary to form a metal-ceramic composite structure by joining the ceramic and the metal by a certain method.

Currently, the most common method of joining ceramic and metallic materials is brazing. The brazing has the advantages of small heat affected zone, reliable formed joint and the like, and is very suitable for connecting different materials. However, the ceramic itself has poor wettability, which makes it difficult to form a good connection between the ceramic and the metal material. Moreover, the thermal expansion coefficient difference between the ceramic and the metal is large, which causes the thermal stress in the joint to be too large, and affects the strength, the air tightness and other performances of the joint.

Disclosure of Invention

The present disclosure has been made in view of the above-described state of the art, and an object thereof is to provide a method for brazing a ceramic and a metal, which can reduce thermal stress of an interface layer and improve the airtightness and the shear strength of the interface layer.

To this end, the present disclosure provides a method of brazing ceramic to metal, comprising: preparing ceramics to be welded and metals to be welded, and performing surface treatment on the ceramics to be welded to form the surface of the ceramics to be welded into a smooth surface; carrying out metallization treatment on the surface of the ceramic to be welded to form an intermediate metal layer combined with the ceramic to be welded, wherein the thermal expansion coefficient of the ceramic to be welded is matched with that of the intermediate metal layer; and sequentially stacking and brazing the ceramics to be welded, the brazing metal and the metal to be welded, wherein the brazing metal is positioned between the middle metal layer and the metal to be welded, in the brazing process, the brazing metal is melted by heating, the melted brazing metal infiltrates the middle metal layer, the molten state of the predetermined time is kept, and a welding surface is formed on an interface between the brazing metal and the ceramics to be welded with the middle metal layer, and annealing and solidifying are carried out.

In the disclosure, the method for brazing ceramic and metal includes the steps of performing surface treatment on the ceramic to be brazed, performing metallization treatment on the surface of the ceramic to be brazed to form an intermediate metal layer with a matched thermal expansion coefficient, and melting and infiltrating the intermediate metal layer by using a metal solder during brazing.

In addition, in the brazing method according to the present disclosure, the roughness of the surface of the ceramic to be welded may be less than 0.05 μm. In this case, the surface of the ceramic to be welded can be smooth and flat, which is beneficial to the subsequent brazing between the ceramic and the metal.

In the brazing method according to the present disclosure, the metallization may be performed by sputtering, vapor deposition, PVD, CVD, plating, or high-temperature sintering. Thereby, a tightly bonded intermediate metal layer can be formed on the surface of the ceramic to be welded.

In the brazing method according to the present disclosure, the intermediate metal layer may be made of at least one selected from Nb, Au, Ti, and alloys thereof. Therefore, the brazing filler metal can well wet the ceramics to be welded with the intermediate metal layer on the surface.

In the brazing method according to the present disclosure, the brazing filler metal may be at least one selected from Au, Ag, Ti, Nb, and alloys thereof. In this case, the wettability of the brazing filler metal to the ceramics to be welded and the metal to be welded can be improved.

In addition, in the brazing method according to the present disclosure, optionally, the sizes of the ceramics to be welded, the metals to be welded, and the brazing filler metal are matched. Therefore, the brazing of the ceramic to be welded and the metal to be welded can be facilitated.

In addition, in the brazing method according to the present disclosure, pressure is optionally applied to the to-be-welded members formed by stacking the to-be-welded ceramics, the brazing metal, and the to-be-welded metal in this order. Thereby, the piece to be welded can be fixed at the time of brazing, and the uniformity of the width of the brazing seam and the edge thereof can be controlled. In addition, in the brazing method according to the present disclosure, the metal to be welded is optionally subjected to a surface treatment before brazing. Thereby, the surface wettability of the metal to be welded can be increased.

In addition, in the brazing method according to the present disclosure, optionally, in the brazing, the temperature is raised to 1060 ℃ to 1150 ℃ at a heating rate of 1 ℃ to 1mi1 to 50 ℃ and 1mi1, the temperature is kept at 1mi1 to 30mi1, and then the temperature is lowered to 200 ℃ to 400 ℃ at a cooling rate of 2 ℃ to 1mi1 to 20 ℃ and 1mi1, and then the temperature is cooled to 150 ℃ or below along with a furnace. Under the condition, the generation and distribution of brittle phases between interfaces can be improved, the strength is increased, the thermal stress and the thermal deformation of a base metal are reduced, cracks in a welding seam are eliminated, and the air tightness and the shearing strength of the interface layer between the ceramic to be welded and the metal to be welded are improved.

In the brazing method according to the present disclosure, the ceramic to be welded may be made of at least one selected from the group consisting of alumina, zirconia, silica, a carbon material, silicon nitride, silicon carbide, titanium oxide, aluminosilicate, and a calcium-aluminum system. In this case, a ceramic to be welded having biocompatibility can be obtained.

According to the present disclosure, a method of brazing ceramic to metal capable of reducing thermal stress of an interface layer and improving the airtightness and shear strength of the interface layer can be provided.

Drawings

Fig. 1 shows a schematic flow diagram of a ceramic to metal brazing method according to an example of the present disclosure.

Fig. 2 shows a perspective view of a jig according to an example of the present disclosure.

Fig. 3 shows a cross-sectional view of the jig shown in fig. 2 along line a-a'.

Fig. 4 shows a cross-sectional view of a jig equipped with a weldment according to an example of the present disclosure.

Fig. 5 shows an assembly structure view of a member to be welded according to an example of the present disclosure.

Fig. 6 illustrates a cross-sectional view of a part to be welded according to an example of the present disclosure.

FIG. 7 shows Al involved in embodiments of the present disclosure ₂O ₃Slice of brazed joint of ceramic to pure Ti metal.

Detailed Description

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same components are denoted by the same reference numerals, and redundant description thereof is omitted. The drawings are schematic and the ratio of the dimensions of the components and the shapes of the components may be different from the actual ones.

The brazing method for ceramic and metal according to the present embodiment includes: preparing ceramics 31 to be welded and a metal 33 to be welded, and surface-treating the ceramics 31 to be welded so as to form the surface of the ceramics 31 to be welded into a smooth surface (step S10); performing metallization processing on the surface of the ceramic to be welded 31 to form an intermediate metal layer bonded to the ceramic to be welded 31, the coefficient of thermal expansion of the ceramic to be welded 31 matching that of the intermediate metal layer (step S20); the ceramics 31 to be welded, the brazing metal 32, and the metals 33 to be welded are stacked in this order and brazed (step S30). In the present embodiment, the parts to be welded 30 may include ceramics to be welded 31, a metal filler 32, and a metal to be welded 33. The shape of the to-be-welded member 30 is not particularly limited, and in some examples, the to-be-welded member 30 may be cylindrical.

In some examples, the braze metal 32 may be located between the middle metal layer and the metal to be welded 33. In addition, in some examples, optionally, in the brazing process, the brazing filler metal 32 is melted by heating, the melted brazing filler metal 32 infiltrates the intermediate metal layer, and is maintained in a melted state for a predetermined time, the interface between the brazing filler metal 32 and the to-be-welded ceramic 31 having the intermediate metal layer is formed into a welding surface, and annealing and solidification are performed.

In the method for brazing ceramic and metal according to the embodiment, the method for brazing ceramic and metal includes performing surface treatment on the ceramic 31 to be brazed, performing metallization treatment on the surface of the ceramic 31 to be brazed to form an intermediate metal layer with a matched thermal expansion coefficient, and melting and infiltrating the intermediate metal layer with the brazing filler metal 32 during brazing, in which case, the melted brazing filler metal 32 can infiltrate the ceramic 31 to be brazed with a metalized surface well, and the intermediate metal layer can make the thermal expansion coefficient of the brazing interface between the ceramic 31 to be brazed and the metal 33 to be brazed present gradient transition, so that the difference of the thermal expansion coefficients caused by different materials between the interfaces can be reduced, the thermal stress of the interface layer can be reduced, and the airtightness can be improved.

In addition, in the present embodiment, during brazing, by selecting an appropriate brazing temperature and holding time, generation and distribution of brittle phases (brittle compounds) between interfaces can be improved, strength is increased, thermal stress and thermal deformation of base materials (to-be-welded ceramics 31 and to-be-welded metals 33) are reduced, cracks in a weld are eliminated, and airtightness and shear strength of an interface layer between the to-be-welded ceramics 31 and the to-be-welded metals 33 are improved.

In some examples, in step S10, the surface of the ceramic 31 to be soldered may be ground and polished to a surface roughness of less than 0.05 μm. In this case, the surface of the ceramic 31 to be welded is smooth and flat, facilitating the subsequent brazing between the ceramic and the metal. In some examples, in step S10, the surface of the ceramic 31 to be welded may be subjected to a grinding process to form a ground surface.

In some examples, the ceramic to be welded 31 may include upper and lower surfaces. This makes it possible to obtain a polished surface obtained by polishing at least one of the upper and lower surfaces of the ceramic 31 to be welded. In this case, since the object to be ground is at least one of the upper and lower surfaces of the ceramic 31 to be welded, the difficulty of the grinding process can be reduced, which facilitates the grinding of the surface of the ceramic 31 to be welded to be flat and smooth, thereby improving the surface wettability of the ceramic 31 to be welded.

In addition, in some examples, the roughness of at least one of the upper and lower surfaces of the ceramic to be welded 31 may be less than 0.05 μm. In this case, the surface of the ceramic 31 to be welded can be made smooth and flat, facilitating subsequent brazing between the ceramic and the metal. In some examples, the roughness of the surface of the ceramic to be welded 31 may be 0.04 μm, 0.03 μm, 0.02 μm, 0.01 μm, or the like.

In some examples, the ceramic to be welded 31 may be biocompatible. This can reduce the destruction to the human body and can adapt to the human tissue. In addition, in some examples, the ceramic to be welded 31 may be an oxide ceramic. Thereby, the ceramics to be welded 31 having stable chemical properties can be obtained.

In some examples, the ceramic 31 to be welded may be made of a material selected from alumina (Al) ₂O ₃) Zirconium oxide (ZrO) ₂) Silicon oxide (SiO2), titanium oxide (TiO 2) ₂) Aluminosilicate (Na) ₂O·Al ₂O ₃·SiO ₂) Or calcium-aluminum (CaO. Al) ₂O ₃) At least one of (1). Thereby, the to-be-welded ceramic 31 having biocompatibility can be obtained.

In the present embodiment, the ceramic to be welded 31 may be alumina (Al) ₂O ₃) A ceramic. In some examples, the ceramic to be welded 31 is preferably composed of alumina (Al) with a mass fraction of 96% or more ₂O ₃) And (4) forming. More preferably, the ceramic to be welded 31 is composed of alumina (Al) with a mass fraction of 99% or more ₂O ₃) Most preferably, the ceramic to be welded 31 is composed of alumina (Al) of 99.99% by mass or more ₂O ₃) And (4) forming. In general, among the ceramics 31 to be welded, alumina (Al) ₂O ₃) It is considered that the mass fraction of alumina (Al) higher than the mass fraction is increased because the main crystal phase is increased and the physical properties of the to-be-welded ceramic 31, such as the pre-compression strength, the bending strength, and the elastic modulus are improved accordingly ₂O ₃) Better biocompatibility and long-term reliability are exhibited. In other examples, the ceramic to be welded 31 may also be zirconium oxide (ZrO) ₂) A ceramic.

In some examples, the ceramic to be welded 31 may be a non-oxide ceramic. For example, the ceramic 31 to be welded may be a carbon material (C), silicon nitride (Si) ₃N ₄) Silicon carbide (SiC)One of the components is omitted.

In some examples, the ceramic 31 to be welded may also be made of silicon oxide (SiO), depending on the application ₂) Potassium oxide (K) ₂O), sodium oxide (Na) ₂O), calcium oxide (CaO), magnesium oxide (MgO), iron oxide (Fe) ₂O ₃) At least one of (1).

In some examples, the ceramic to be welded 31 may be disk-shaped. But examples of the present invention are not limited thereto, and for example, the ceramic to be welded 31 may have a square shape.

In the present embodiment, the metal to be welded 33 may have biocompatibility. This can reduce the destruction to the human body and can adapt to the human tissue. In some examples, in step S10, the metal to be welded 33 may be selected from at least one of Ti (titanium), Nb (niobium), Ni (nickel), Zr (zirconium), Ta (tantalum), and alloys thereof. Thereby, the metal to be welded 33 having biocompatibility can be obtained. In addition, in one example, the metal 33 to be welded may be pure Ti. In another example, the metal to be welded 33 may be a Ti alloy. In addition, in yet another example, the metal to be welded 33 may be an iron-nickel alloy.

In some examples, the metal to be welded 33 may be a non-biocompatible metal. For example, the metal to be welded 33 may be made of at least one selected from copper (Cu), iron (Fe), magnesium (Mg), lead (Pb), aluminum (Al), and alloys thereof, and the like.

Fig. 6 shows a cross-sectional view of a to-be-welded part 30 according to an example of the present disclosure.

In some examples, as shown in fig. 6, the metal to be welded 33 may have an annular protrusion 331. In this case, subsequent cooperation of the part to be welded 30 with other components (not shown) is facilitated. In some examples, the metal to be welded 33 may be integrally formed.

In some examples, the annular protrusion 331 may extend along the inner diameter direction. In addition, in some examples, the inner diameter of the annular protrusion 331 may be smaller than the inner diameter of the brazing filler metal 32 (described later), i.e., the inner diameter of the annular protrusion 331 may be smaller than the inner diameter of the brazing filler metal 32. This enables the brazing material to be fitted to the brazing filler metal 32, thereby facilitating brazing.

In this embodiment, before step S20, a surface treatment may be performed on the metal 33 to be welded. Thereby, the surface wettability of the metal 33 to be welded can be increased.

In some examples, the metal to be welded 33 may be surface-treated using sanding in stages to treat the metal to be welded 33. This makes it possible to polish the surface of the metal 33 to be welded to an appropriate roughness and increase the wettability of the metal 33 to be welded. For example, in one example, the metals 33 to be welded may be progressively ground with #200, #400, #600, #1200, #2000, and #4000 sandpaper. In another example, the metals to be welded 33 may be progressively ground with #100, #300, #500, #1000, #1500, #2500, and #4000 sandpaper. In addition, in yet another example, the metals 33 to be welded may be progressively ground with #280, #400, #800, #1600, #2500, #3500, and #5000 sandpaper.

In some examples, the flatness of the metal to be welded 33 after surface treatment may be 8 to 10 μm. In this case, the brazing filler metal 32 can be bonded better, which is advantageous for brazing. For example, the flatness of the metal 33 to be welded after surface treatment may be 8 μm, 8.2 μm, 8.5 μm, 8.8 μm, 9 μm, 9.2 μm, 9.5 μm, 9.8 μm, or 10 μm.

In addition, in some examples, the flatness of the metal 33 to be welded may take into account factors in the thickness of the metal filler metal 32. In some examples, the thicker the thickness of the metal braze 32, the greater the flatness that can be tolerated by the metal to be welded 33, and conversely, the smaller the flatness that can be tolerated by the metal to be welded 33.

In addition, in the present embodiment, before step S20, cleaning of the metal to be welded 33 after grinding may be included. In some examples, the ground metal to be welded 33 may be cleaned with ethanol 10mi1 to 20mi1 and then with isopropanol 10mi1 to 20mi 1. For example, the metal 33 to be welded after grinding may be washed with ethanol 15mi1 and then with isopropanol 15mi 1. Therefore, foreign matters on the surface of the technology to be welded can be removed, and the subsequent brazing is facilitated.

In some examples, in step S20, the metallization process may be sputtering, evaporation, plating, or high temperature sintering. This enables the formation of an intermediate metal layer bonded to the surface of the ceramic 31 to be welded. In other examples, the metallization process is preferably sputtering.

In some examples, the method of metallization may be PVD (physical vapor deposition) or CVD (chemical vapor deposition). In other examples, the metallization process may be magnetron sputtering. Additionally, in some examples, the method of metallization may be a low temperature processing method. For example, the temperature of magnetron sputtering may not exceed 300 ℃.

In some examples, in step S20, the intermediate metal layer may be composed of at least one selected from Nb, Au, Ti, and alloys thereof. Thereby, the ceramics to be welded 31 having the intermediate metal layer on the surface can be well wetted. In addition, in some examples, the intermediate metal layer may be composed of Nb, in other words, the intermediate metal layer may be a niobium layer formed of Nb. Further, the intermediate metal layer made of Nb has good bonding ability with the alumina ceramic, and thus can contribute to improvement in the reliability of brazing the ceramics to be welded 31 and the metals to be welded 33.

In some examples, the ground surface of the ceramic 31 to be soldered may be metallized to form an intermediate metal layer. That is, an intermediate metal layer may be formed on the ground surface of the ceramic 31 to be welded. In other examples, the surface of the ceramic 31 to be soldered may be formed into a soldered surface by surface grinding and metallization.

In addition, in this embodiment, in step S20, the thermal expansion coefficient of the ceramic to be welded 31 is matched with the thermal expansion coefficient of the intermediate metal layer, that is, the thermal expansion coefficient of the intermediate metal layer may be between the thermal expansion coefficient of the ceramic to be welded 31 and the thermal expansion coefficient of the metal to be welded 33, so that the thermal expansion coefficient between the interfaces of the ceramic to be welded 31 and the metal to be welded 33 can be in a gradient transition, the difference in thermal expansion coefficient between the interfaces due to the difference in materials is reduced, the thermal stress of the interfaces is reduced, and the performance is improved.

In some examples, the metallization may be limited to the edge locations of the braze face. In other words, a metalized braze surface may be formed at the edge of the ground surface to match the braze 32. In this case, the intermediate metal layer can be formed at the position of the ceramic to be welded 31 that is brazed with the metal to be welded 33. In other examples, the metallization may be performed over the entire abrasive surface. In other examples, the metallization may be performed only in the middle of the abrasive surface.

In some examples, the edge locations of the braze faces may be formed with an intermediate metal layer. Thereby, the welding between the ceramic 31 to be welded and the metal 33 to be welded can be facilitated.

In some examples, the shape of the intermediate metal layer may be selected based on the shape of the metal to be welded 33. For example, the metal to be welded 33 is in the shape of a ring, and the intermediate metal layer may be in the shape of a ring. Additionally, in some examples, the middle metal layer may have a ring width equal to the metal to be welded 33. Thereby, the welding between the ceramic 31 to be welded and the metal 33 to be welded can be facilitated.

In some examples, the intermediate metal layer may be placed under a microscope to observe the intermediate metal layer mass at 500 x to 1000 x magnification. For example, it is observed whether the intermediate metal layer is tight, whether the appearance is flat, or the like.

In some examples, in step S20, magnetron sputtering may be used to sputter Nb onto the positions to be brazed of the ceramic 31 to be brazed, and the sputtered Nb may become a flat intermediate metal layer on the positions to be brazed. For example, the position to be brazed may be an edge position of the ceramic to be brazed 31 covered with the brazing metal 32 in fig. 6.

In addition, in the present embodiment, in step S20, cleaning of the to-be-welded ceramic 31 having the intermediate metal layer may be included. This can remove foreign matter on the surface of the ceramic 31 to be welded, which is advantageous for the subsequent brazing. In some examples, the ceramic 31 to be welded with the intermediate metal layer may be cleaned with ethanol from 3mi1 to 5mi1 and then with isopropanol from 3mi1 to 5mi 1. For example, in one example, the ceramic 31 to be welded with an intermediate metal layer may be cleaned with ethanol at 4mi1 and then with isopropanol at 4mi 1.

In some examples, prior to step S30, preparing the braze metal 32 may also be included. In other examples, the brazing filler metal 32 may be in the form of a sheet. In this case, it can be facilitated for the brazing filler metal 32 to melt and infiltrate the materials to be welded (the ceramics 31 to be welded, the metals 33 to be welded, etc.). For example, as shown in fig. 6, the brazing filler metal 32 may be in the form of a ring-shaped sheet. The present embodiment is not limited thereto, and in some examples, the brazing filler metal 32 may be in the form of powder, paste, wire, strip, or the like.

In some examples, the metallic filler metal 32 may be biocompatible. The brazing filler metal 32 may be at least one selected from Au, Ag, Ti, Nb, and alloys thereof. In this case, a brazing layer having biosafety can be formed. For example, the metallic solder 32 may be pure Au. In addition, in some examples, the molten pure Au has good wettability to the niobium layer, and thus can contribute to improvement in the reliability of soldering the to-be-soldered ceramic 31 and the to-be-soldered metal 33.

Additionally, a metal braze 32 may be disposed on the braze face. In some examples, the braze metal 32 may be disposed on an intermediate metal layer.

In some examples, as shown in fig. 2, the metallic filler metal 32 may be disposed on an edge location. In this case, brazing can be performed on the intermediate metal layer of the ceramic 31 to be welded. In other examples, the metal braze 32 may be disposed over the entire braze surface. In some examples, the metal braze 32 may be disposed in an intermediate position to the braze surface.

In addition, in the present embodiment, the step S30 may include preprocessing the brazing filler metal 32. In some examples, the braze metal 32 may be surface treated using a sanding step-wise sanding of the braze metal 32. This can remove the oxide film on the surface. For example, in one example, the braze metal 32 may be sanded in stages with #200, #400, #600, #1200, #2000, and #4000 sandpaper. In another example, the brazing filler metal 32 may be sanded with #100, #300, #500, #1000, #1500, #2500, and #4000 sandpaper in stages. In addition, in yet another example, the brazing filler metal 32 may be sanded with #280, #400, #800, #1600, #2500, #3500, and #5000 sandpaper in stages.

In some examples, the sizes of the ceramic 31 to be welded, the metal 33 to be welded, and the brazing filler metal 32 may be matched. This can facilitate brazing of the ceramic 31 to be welded and the metal 33 to be welded. For example, the outer diameter of the metal filler 32 may be smaller than the outer diameter of the ceramics 31 to be welded, and the outer diameter of the metal 33 to be welded may be equal to the outer diameter of the ceramics 31 to be welded.

In some examples, the outer diameter of the metallic filler metal 32 may be smaller than the outer diameter of the ceramic 31 to be welded. In other examples, the difference between the outer diameter of the ceramic 31 to be welded and the outer diameter of the brazing metal 32 may not exceed 0.05 mm. For example, the difference between the outer diameter of the ceramic 31 to be welded and the outer diameter of the brazing filler metal 32 may be 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, or the like.

In some examples, the inner diameter of the metal to be welded 33 may be smaller than the diameter of the ceramic to be welded 31. In addition, the metal to be welded 33 may have an outer diameter equal to that of the ceramic to be welded 31.

In some examples, the outer diameter of the metal to be welded 33 may be larger than the outer diameter of the ceramic to be welded 31. In other examples, the outer diameter of the metal to be welded 33 may be smaller than the outer diameter of the ceramic to be welded 31.

In some examples, the inner diameter of the metal filler metal 32 may be smaller than the inner diameter of the metal 33 to be welded. In other words, the ring width of the brazing metal 32 may be smaller than that of the metal 33 to be welded. In other examples, the difference between the inside diameter of the metal filler metal 32 and the inside diameter of the metal to be welded 33 may not exceed 0.05 mm. For example, the difference between the inner diameter of the brazing metal 32 and the inner diameter of the metal 33 to be welded may be 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, or the like. In addition, the inner diameter of the metal 33 to be welded may refer to the inner diameter of the annular protrusion 331.

In some examples, the intermediate metal layer may be matched to the metal to be welded 33. Additionally, in some examples, the inner diameter of the middle metal layer may be equal to the inner diameter of the metal to be welded 33. In other examples, the outer diameter of the middle metal layer may be equal to the outer diameter of the metal to be welded 33.

In some examples, the loop width of the middle metal layer may be equal to the loop width of the metal to be welded 33. In some examples, the loop width of the middle metal layer may be greater than the loop width of the metal to be welded 33.

In some examples, the outer diameter of the ceramic to be welded 31 may be 10mm to 9.9 mm. For example, the outer diameter of the ceramic 31 to be welded may be 9.9mm, 9.91mm, 9.92mm, 9.93mm, 9.94mm, 9.95mm, 9.96mm, 9.97mm, 9.98mm, 9.99mm, or 10 mm.

In some examples, the outer diameter of the metal to be welded 33 may be 10.1mm to 9.9 mm. For example, the outer diameter of the metal 33 to be welded may be 9.9mm, 9.92mm, 9.95mm, 9.98mm, 10mm, 10.02mm, 10.05mm, 10.08mm, or 10.1 mm.

In some examples, the inner diameter of the metal to be welded 33 may be 8.9mm to 8.7 mm. For example, the inner diameter of the metal 33 to be welded may be 8.7mm, 8.72mm, 8.75mm, 8.78mm, 8.8mm, 8.82mm, 8.85mm, 8.88mm, or 8.9 mm.

In some examples, the ring width of the metal to be welded 33 may be 0.5mm to 0.7 mm. For example, the ring width of the metal 33 to be welded may be 0.5mm, 0.52mm, 0.55mm, 0.58mm, 0.6mm, 0.62mm, 0.65mm, 0.68mm, or 0.7 mm.

In other examples, the thickness of the brazing filler metal 32 may be 80 μm to 120 μm. For example, the thickness of the brazing filler metal 32 may be 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, or 120 μm.

In some examples, pressure is optionally applied to the to-be-welded part 30 formed by stacking the to-be-welded ceramic 31, the brazing metal 32, and the to-be-welded metal 33 in this order. Thereby, the member to be welded 30 can be fixed at the time of brazing, and the uniformity of the brazing seam width and the edge thereof can be controlled.

The jig 1 for brazing used in step 30 according to the present embodiment will be described in detail below with reference to the drawings.

Fig. 2 shows a perspective view of a jig 1 according to an example of the present disclosure. Fig. 3 shows a cross-sectional view of the jig 1 shown in fig. 2 along the line a-a'. In fig. 3, a cover body that engages with the stage 10 is omitted for convenience of illustration of the structure of the stage 10.

In the present embodiment, the jig for brazing (hereinafter, sometimes referred to as "jig") 1 may include a stage 10 and a compact 20 fitted to the stage 10. In step S30, soldering of the to-be-soldered piece 30 can be achieved by sequentially placing the to-be-soldered pieces 30 (the to-be-soldered ceramics 31, the metal filler metal 32, and the to-be-soldered metal 33) on the stage 10 and disposing the compact 20 fitted to the stage 10 on the to-be-soldered piece 30.

Additionally, in some examples, the stage 10 may be semi-cylindrical. In this case, brazing can be performed better. For example, the semi-cylindrical stage 10 may be placed in a brazing tube furnace (not shown) having a cylindrical furnace tube and brazed. In addition, the shape of the stage 10 can be matched to the shape of the furnace tube of the brazing tube furnace. In this case, the fixture 1 is advantageously fixed in the brazing tube furnace, and the brazing can be performed better. For example, the furnace tube of the brazing tube furnace may be prismatic, and the stage 10 may also be prismatic.

In the present embodiment, a vacuum pump (not shown) may be connected to the brazing tube furnace. In some examples, the vacuum level within a brazing tube furnace (not shown) may be 10 ^-4pa. In other examples, the vacuum level in a brazing tube furnace (not shown) may be 10 ^-3pa. In addition, in yet another example, the vacuum level within a brazing tube furnace (not shown) may be 10 ^-2pa。

Additionally, in some examples, the degree of vacuum within the brazing tube furnace (not shown) may also be 8 x 10, depending on the brazing filler metal (brazing filler metal 32) selected ^-3pa、5×10 ^-3pa、3×10 ^-3pa、7×10 ^-2pa、5× 10 ^-2pa、2×10 ^-2pa or 1 pa.

In addition, in some examples, the stage 10 may have a through hole 12 (see fig. 4). In addition, the through-hole 12 may penetrate the bottom 11a of the groove 11. In some examples, the stage 10 may have at least one groove (e.g., the groove 11 in fig. 3, fig. 3 showing an example of four grooves 11), and a through hole (through hole 12) penetrating the stage 10 from a bottom 11a of the groove (groove 11).

In some examples, the groove 11 may be used to place the parts to be welded 30 (including the ceramics to be welded 31, the metal filler 32, and the metal to be welded 33) and may be capable of cooperating with the compact 20. Additionally, in some examples, the compact 20 may have a vent 21.

In addition, when the plurality of grooves 11 are provided in the stage 10, the plurality of workpieces to be welded 30 can be simultaneously brazed in a batch manner, and the work efficiency is improved. For example, in addition to the illustration of fig. 3, there may be 2, 8, 12, 16 or 20 grooves 11 in the object table 10.

In some examples, the press block 20 can fix the to-be-welded piece 30 during the brazing process, avoiding displacement of the to-be-welded piece 30 during the brazing process. In addition, gas flow can be formed in the through hole 12 and the vent hole 21 of the jig 1, so that the temperature distribution of the jig 1 can be uniform in the brazing process, the to-be-welded piece 30 is heated uniformly, and the vent hole 21 can discharge impurities such as metal steam generated in the brazing process, so that the to-be-welded piece 30 is prevented from being polluted.

In some examples, the bottom 11a of the groove 11 may be flat (see fig. 3). Thereby, the member to be welded 30 can be smoothly placed on the bottom 11a of the recess 11.

In some examples, the groove 11 may be cylindrical. In this case, it can be applied particularly to the same cylindrical member to be welded 30. However, the present embodiment is not limited thereto, and in some examples, the groove 11 may have a prism shape or the like. For example, in one example, the groove 11 may have a rectangular parallelepiped shape. In another example, the groove 11 may be square.

In addition, in some examples, the inner diameter of the groove 11 may be equal to the expansion size of the member to be welded 30 at the brazing temperature plus the expansion size of the jig 1 at the brazing temperature plus the reserved size. In some examples, the reserved size may be 0.02mm-0.03 mm. For example, the reserved size may be 0.02mm, 0.022mm, 0.025mm, 0.028mm, 0.03mm, and the like.

In addition, in some examples, there can be a flow of hot gas in the through-holes 12, so that the temperature distribution in the stage 10 can be made uniform during the brazing process, and thus the to-be-welded piece 30 is heated uniformly. In addition, the presence of the through-holes 12 also enables easier cleaning of the grooves 11. In addition, since the through hole 12 can penetrate through the bottom 11a of the groove 11, the groove 11 can be used for placing the to-be-welded part 30, and therefore the through hole 12 can facilitate taking out the part.

In addition, in some examples, the jig 1 may further include a cover (not shown) covering the stage 10. In this case, the atmosphere during brazing can be protected, and the degree of vacuum can be maintained well.

Additionally, in some examples, the stage 10 may have a groove 13 surrounding the recess 11, and an edge of a cover (not shown) may mate with the groove 13. Thereby, the cover (not shown) can cover the stage 10. In some examples, the edge of the cover may snap into the groove 13.

Additionally, in some examples, as shown in fig. 4, the compact 20 may be a combination of two cylinders having different inner diameters. In such a compact 20, the cylinder having a small inner diameter has a small diameter and thus can fit into the groove 11, and the cylinder having a large inner diameter has a large diameter and thus can cover the groove 11. In this case, the pressing of the workpiece to be welded 30 can be achieved by the pressing block 20.

In some examples, the diameter of the cylinder having a small inner diameter may be smaller than the inner diameter of the groove 11 in the compact 20. In addition, in some examples, in the compact 20, the diameter of the cylinder having a small inner diameter may be larger than the inner diameter of the metal 33 to be welded. In other examples, the diameter of the cylinder having a large inner diameter may be larger than the inner diameter of the groove 11 in the pressing block 20.

In other examples, the compact 20 may be a prism. Additionally, in some examples, the compact 20 may be a circular truncated cone. Additionally, in some examples, the compact 20 is integrally formed. In addition, in some examples, the compact 20 may be utilized to apply pressure to the ceramic 31 to be welded and the metal 33 to be welded.

In some examples, a vent 21 may be provided in the compact 20. Additionally, in some examples, the compact 20 may have a plurality of vent holes 21, for example, the compact 20 may have 2, 3 vent holes 21. In this case, since a gas flow can be formed in the vent hole 21, the temperature distribution in the stage 10 can be made uniform during the brazing process, and the to-be-welded member 30 can be heated uniformly. In addition, the vent holes 21 can also help to discharge impurities such as metal vapor generated during the brazing process, thereby preventing the member to be welded 30 from being contaminated.

In some examples, among the plurality of vent holes 21, there may be a vent hole 21 penetrating in the length direction. In this case, the uniformity of heating of the to-be-welded member 30 can be further improved, and contamination of the to-be-welded member 30 can be better avoided.

In some examples, the compact 20 may be used to apply pressure to the ceramic 31 to be welded and the metal 33 to be welded, respectively. In this case, the consistency of the width of the brazing seam and its edges can be well controlled and the piece to be welded 30 can be fixed at the time of brazing.

In addition, in some examples, the to-be-welded piece 30 may be located between the bottom 11a of the groove 11 and the compact 20. Thereby, the to-be-welded piece 30 can be well fixed in the groove 11.

In the present embodiment, the material of the stage 10 may be at least one selected from graphite, silicon, synthetic stone, boron carbide, silicon carbide, boron nitride, silicon nitride, boron phosphide, and silicon phosphide. In one example, the material of the stage 10 may be graphite. In another example, the material of the stage 10 may be synthetic stone.

In the present embodiment, the material of the compact 20 may be at least one selected from graphite, silicon, synthetic stone, boron carbide, silicon carbide, boron nitride, silicon nitride, boron phosphide, and silicon phosphide. In one example, the material of the compact 20 may be graphite. In another example, the material of the compact 20 may be synthetic stone.

In addition, in some examples, the length of the jig 1 and the grooves 11 may be distributed in a temperature zone of the brazing tube furnace where the temperature is uniform. Thereby, the plurality of members to be welded 30 can be brazed well at the same time.

In addition, in the present embodiment, as shown in fig. 4, in step S30, the to-be-welded part 30 may be placed in the groove 11 on the stage 10, and the to-be-welded part 30 may be pressed by the pressing block 20, so that the assembly may be completed. The assembled stage 10, compact 20 and piece to be welded 30 are then fed into, for example, a brazing tube furnace for brazing. In some examples, the assembled stage 10, compact 20, and part 30 to be welded are fed into a temperature uniform zone of a brazing tube furnace. Thereby, the plurality of members to be welded 30 can be brazed well at the same time.

In addition, in some examples, the order in which the parts of the to-be-welded piece 30 in fig. 4 are stacked from below to above in the groove 11 may be a ceramic to be welded 31, a metal filler 32, and a metal to be welded 33 (see fig. 2 and 6). For example, the order in which the parts of the parts 30 to be welded are stacked from below to above in the groove 11 may be disk-shaped Al ₂O ₃Ceramic, pure Au solder ring, pure Ti metal ring, and disc-shaped Al ₂O ₃The centers of the ceramic, pure Au solder ring and the pure Ti metal ring can be at the same point, and the disc-shaped Al ₂O ₃The outer diameter of the ceramic and the pure Ti metal ring are approximately the same, and the outer diameter of the pure Au solder ring is larger than that of the disc-shaped Al ₂O ₃The outer diameter of the ceramic is at most 0.05 mm.

In some examples, there may be a gap between the compact 20 and the side wall of the recess 11 of the stage 10. In addition, in some examples, the clearance H between the pressing block 20 and the side wall of the groove 11 of the stage 10 may be 0.05mm to 0.06mm (see fig. 6), in which case the expansion dimension of the jig 1 and the to-be-welded piece 30 can be reserved, and the device can be smoothly taken out when the brazing is completed. In addition, a gap is formed between the compact 20 and the side wall of the groove 11, whereby impurities such as metal vapor generated during the brazing process can be further discharged.

In some examples, the jig 1 may also have a collar. In other examples, a collar may be placed within the recess 11 and may surround the part to be welded 30. In this case, the flow of the brazing filler metal 32 after melting can be reduced.

In some examples, the inner diameter of the groove 11 may be equal to the expansion size at the brazing temperature of the part to be welded 30 plus the expansion size at the brazing temperature of the jig 1 plus the thickness and the pre-set size of the collar.

In addition, in some examples, in order to prevent the brazing filler metal 32 in the to-be-welded part 30 from flowing out during the brazing process, the method can be implemented by calculating the usage amount of the brazing filler metal 32, controlling the heat preservation time and the surface state of the base metal, and the like.

Fig. 4 shows a cross-sectional view of a jig 1 equipped with a member to be soldered 30 according to an example of the present disclosure.

Fig. 5 shows an assembly structure view of a to-be-welded 30 according to an example of the present disclosure.

In addition, in the present embodiment, in step S30, as shown in fig. 4, the to-be-welded part 30 may be placed in the groove 11 on the stage 10, and the to-be-welded part 30 may be pressed by the pressing block 20, so that the assembly may be completed. The assembled stage 10, compact 20 and piece to be welded 30 are then fed into, for example, a brazing tube furnace for brazing. In some examples, the assembled stage 10, compact 20, and part 30 to be welded are fed into a temperature uniform zone of a brazing tube furnace. Thereby, the plurality of members to be welded 30 can be brazed well at the same time.

In addition, in some examples, the clearance H between the compact 20 and the side wall of the groove 11 of the stage 10 may be 0.05mm to 0.06mm (see fig. 4), in which case the weldment can be smoothly taken out at the time of completion of brazing. In addition, as described above, the stage 10 may have a plurality of grooves 11, thereby enabling brazing of a plurality of pieces to be brazed 30 at the same time. For example, in addition to the illustrations of fig. 2 and 3, there may be 4, 12, 16 or 20 grooves 11 in the stage 10.

In addition, in some examples, the components of the parts to be welded 30 may be stacked from below to above in the groove 11 in the order of the ceramics to be welded 31, the brazing metal 32, and the metal to be welded 33 (see fig. 5). For example, the order in which the parts of the piece to be welded 30 are stacked from below to above in the groove 11 may be circular Al ₂O ₃Ceramic substrate, pure Au solder ring and pure Ti metal ring, and circular Al ₂O ₃The ceramic substrate, pure Au solder ring and pure Ti metal ring have approximately the same outer diameter.

In addition, in the present embodiment, in step S30, the to-be-soldered piece 30 may be heated up to 1060 ℃ to 1150 ℃ at a heating rate of 1 ℃ 1mi1 to 50 ℃ 1mi1, held at 1mi1 to 30mi1, then cooled down to 200 ℃ to 400 ℃ at a cooling rate of 2 ℃ 1mi1 to 20 ℃ 1mi1, and then furnace-cooled to 150 ℃ or less. Wherein 1060 ℃ to 1150 ℃ can be used as the brazing temperature. In this case, it is possible to improve the generation and distribution of brittle phases between interfaces, increase strength, reduce thermal stress and thermal deformation of the base material, eliminate cracks in the weld, and improve the airtightness and shear strength of the interface layer between the ceramic 31 to be welded and the metal 33 to be welded.

In addition, in some examples, in step S30, the temperature may be raised to 1060 ℃ at a heating rate of 20 ℃ 1mi1, held at 1mi1, then lowered to 400 ℃ at a cooling rate of 10 ℃ 1mi1, and then furnace-cooled to 150 ℃. In other examples, the temperature may be raised to 1065 ℃ at a heating rate of 15 ℃ 1mi1, held at 3mi1, then lowered to 250 ℃ at a cooling rate of 12 ℃ 1mi1, and then furnace cooled to 140 ℃. In addition, in yet another example, the temperature may be raised to 1100 ℃ at a heating rate of 30 ℃ 1mi1, held at 5mi1, then lowered to 300 ℃ at a cooling rate of 8 ℃ 1mi1, and then furnace cooled to 120 ℃.

Depending on the brazing material (brazing filler metal 32) selected, the brazing temperature may be 850 ℃, 900 ℃, 950 ℃, 1000 ℃, 1050 ℃, 1150 ℃, 1200 ℃, or the like.

In some examples, after brazing, an interfacial layer may be formed between the interface of the ceramic 31 to be welded and the metal 33 to be welded. Additionally, in some examples, the interface layer may include the braze metal 32 and the IMC layer. In other examples, the IMC layer may be a continuous IMC layer. In some examples, the IMC layer may be a discontinuous IMC layer.

In some examples, the IMC layer may be located between the metal 33 to be welded and the braze metal 32. Additionally, in some examples, the interface layer may include multiple layers of IMC. For example, there may be 2, 3, 4 or 5 IMC layers in the interface layer. Additionally, in some examples, multiple layers of IMC layers may each be located between the metal 33 to be welded and the braze metal 32.

In some examples, the multilayer IMC layer may include a brittle phase layer. In addition, in some examples, the brittle phase layer may refer to an alloy layer having a large content of a brittle phase (brittle compound). In other examples, the thickness of the brittle phase layer may not exceed 2 μm. For example, the brittle phase layer may have a thickness of 0.5 μm, 0.8 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, or 2 μm.

In order to further illustrate the present disclosure, the brazing method of ceramic and metal provided by the present disclosure is described in detail below with reference to the examples, and the advantages achieved by the present disclosure are fully illustrated.

[ examples ] A method for producing a compound

(1) For disc-shaped Al ₂O ₃Carrying out surface grinding and polishing on the upper surface of the ceramic until the surface roughness is 0.02 mu m;

(2) for polished Al ₂O ₃The upper surface of the ceramic is metallized by sputtering Nb to Al by magnetron sputtering ₂O ₃Obtaining to-be-welded metallized ceramic on the to-be-welded surface of the ceramic;

(3) cleaning the to-be-welded metalized ceramic by using ethanol for 4mi1, and then cleaning by using isopropanol for 4mi1 to obtain clean to-be-welded metalized ceramic;

(4) polishing annular pure Ti metal and annular flaky pure Au foil solder by using #200, #400, #600, #1200, #2000 and #4000 sandpaper step by step, then cleaning by using ethanol for 10mi1, and cleaning by using isopropanol for 15mi1 to obtain clean pure Ti metal and pure Au foil solder;

(5) sequentially stacking clean to-be-welded metallized ceramic, pure Au foil solder and pure Ti metal in a jig from bottom to top in sequence, and fixing to obtain a to-be-welded part;

(6) and (3) placing the jig provided with the piece to be brazed in a vacuum brazing furnace, heating to 1060 ℃ at the heating rate of 20 ℃ and 1mi1, preserving heat at 1mi1, then cooling to 400 ℃ at the cooling rate of 10 ℃ and 1mi1, and finally cooling to 150 ℃ along with the furnace to finish brazing.

Finally, opening the furnace to take out Al ₂O ₃Brazing joint of ceramic and pure Ti metal, then performing air tightness test and room temperature shear strength test on the brazing joint, and performing slice observation on the brazing jointAnd (4) organizing the structure.

The test results of the air tightness test and the room temperature shear strength test of the brazed joint in the embodiment are as follows: the airtightness is 1E-10 m ³1s, and the room-temperature shear strength is 20 Mpa.

As a result of slicing the soldered joints, as shown in FIG. 7, it was observed from FIG. 7 that the solder of pure Au completely filled the solder joints, and defects such as voids and non-joints were not generated in the solder joints, and the solder and the base materials (Al) on both sides ₂O ₃Ceramic and pure Ti metal) interface reaction is sufficient, a good metallurgical bond is formed, and Al ₂O ₃Neither the ceramic side nor the braze showed cracks, and the brittle phase was distributed only on the pure Ti metal side. In addition, most brazing seams are made of pure Au brazing filler metal, so that the thermal stress of the brazed joint can be effectively relieved, and the strength of the brazed joint can be improved.

In summary, the brazed joint obtained in the examples has low thermal stress and good airtightness and shear strength.

While the present disclosure has been described in detail above with reference to the drawings and the embodiments, it should be understood that the above description does not limit the present disclosure in any way. Those skilled in the art can make modifications and variations to the present disclosure as needed without departing from the true spirit and scope of the disclosure, which fall within the scope of the disclosure.

Claims

1. A method for brazing ceramic and metal, characterized in that:

the method comprises the following steps:

preparing ceramics to be welded and metals to be welded, and performing surface treatment on the ceramics to be welded to form the surface of the ceramics to be welded into a smooth surface;

carrying out metallization treatment on the surface of the ceramic to be welded to form an intermediate metal layer combined with the ceramic to be welded, wherein the thermal expansion coefficient of the ceramic to be welded is matched with that of the intermediate metal layer; and is

Sequentially stacking the ceramics to be welded, the metal solder and the metal to be welded and brazing, wherein the metal solder is positioned between the middle metal layer and the metal to be welded,

in the brazing process, the metal brazing filler metal is melted through heating, the melted metal brazing filler metal infiltrates the middle metal layer and is kept in a molten state for a preset time, so that a welding surface is formed on an interface between the metal brazing filler metal and the ceramic to be welded with the middle metal layer, and annealing and solidification are carried out.

2. The brazing method according to claim 1, wherein:

the roughness of the surface of the ceramic to be welded is less than 0.05 μm.

3. The brazing method according to claim 1, wherein:

the metallization treatment method is sputtering, evaporation, plating or high-temperature sintering.

4. The brazing method according to claim 1, wherein:

the intermediate metal layer is composed of at least one selected from Nb, Au, Ti and alloys thereof.

5. The brazing method according to claim 1, wherein:

the metal solder is at least one selected from Au, Ag, Ti, Nb and alloys thereof.

6. The brazing method according to claim 1, wherein:

the sizes of the ceramic to be welded and the metal to be welded are matched with the size of the metal brazing filler metal.

7. The brazing method according to claim 1 or 6, wherein:

and applying pressure to the to-be-welded piece formed by sequentially stacking the to-be-welded ceramic, the metal solder and the to-be-welded metal.

8. The brazing method according to claim 1, wherein:

before brazing, the metal to be welded is subjected to surface treatment.

9. The brazing method according to claim 1, wherein:

in the brazing, the temperature is raised to 1060 ℃ to 1150 ℃ at the heating rate of 1 ℃ 1mi1 to 50 ℃ 1mi1, the temperature is kept between 1mi1 and 30mi1, then the temperature is lowered to 200 ℃ to 400 ℃ at the cooling rate of 2 ℃ 1mi1 to 20 ℃ 1mi1, and then the temperature is cooled to below 150 ℃ along with a furnace.

10. The brazing method according to claim 1, wherein:

the ceramic to be welded is composed of at least one selected from alumina, zirconia, silica, titania, aluminosilicate or calcium-aluminum series.