CN100434218C - Application method of surface alloyed ceramics - Google Patents

Abstract

An application method of surface alloyed ceramics, which uses the chemical and physical properties of the surface alloyed ceramics to have composite target material active metal titanium, zirconium, hafnium and metal copper, aluminum, iron, manganese, chromium, etc. Brazing connection method with metal materials, under low vacuum, brazing connection of Al ₂ O ₃ ceramics and metal aluminum foil, arc glow brazing of Al ₂ O ₃ ceramics and metal carbon steel Q235B, Si ₃ N ₄ ceramics Brazing connection with carbon steel Q235B, ZrO ₂ ceramics brazed with carbon steel Q235B under atmospheric conditions, and Al ₂ O ₃ ceramic laminates brazed in a vacuum furnace. The advantage of this method is that no flux is needed for the brazing of surface alloyed ceramics and metal materials, the brazing bonding strength is high, up to 160-180MPa, it has good oxidation resistance, the brazing speed is fast, and the efficiency is high. It is used in various industrial fields and welding technology.

Description

Application method of surface alloyed ceramics

divisional application

Original application number: 200410012575.1

Date of filing the original case: September 30, 2004

Title of original application: Preparation method of surface alloyed ceramics

1. Technical field

The application method of the surface alloyed ceramics of the invention relates to the technical fields of ceramic surface modification technology and composite material preparation.

2. Background technology

Ceramic materials have many advantages, such as high temperature resistance, corrosion resistance, high hardness, wear resistance, and good electrical insulation. Therefore, ceramic materials have been widely used. However, due to the inevitable disadvantages of ceramics, such as brittleness, strength dispersion and poor processability, the further use of ceramics is limited. Alloying the surface of ceramics to form surface alloyed ceramics is the main way to maximize the strengths and avoid weaknesses to expand the application of ceramics. Therefore, surface alloyed ceramics have broad application prospects.

The biggest difficulty in metallizing ceramic surfaces is that the bonding mechanism of ceramic materials and metal materials is different. Ceramic materials are covalent bonds, while metal materials are metal bonds, so metals are difficult to wet and spread on the surface of ceramic materials. Therefore, many methods of ceramic surface metallization have been produced, among which Mn-Mo method and vapor deposition method are the most commonly used methods. The Mn-Mo method is to sinter Mn and Mo powder materials on the ceramic surface during the complex sintering process. This metallization process reduces the surface finish and performance of the ceramics; the vapor deposition metallization method is characterized by ceramics that do not withstand high temperatures. , can ensure the dimensional accuracy of the parts, the metallized film is continuous and dense, has good thermal conductivity, low high-frequency loss, and high strength, but it can only deposit a single metal element, so it can only be called a ceramic surface metallization method. In addition, because it has no activity Due to the effect of elements, the bonding strength between the metal layer and the ceramic is low.

Based on the beneficial effect of the chemical reaction between active element titanium and ceramics, the applicant has carried out arc glow titanium infiltration on the ceramic surface, but this method only makes the ceramic surface realize titanium metallization, the metal element is single, and the adaptability is poor , and due to the strong oxygen affinity of titanium, the metal titanium layer is easily oxidized by the atmosphere, and the formation of an oxide film is not conducive to the subsequent application process. For example, in the connection between ceramics and metals based on this, since the titanium layer permeated on the surface of the ceramics is difficult to react and mix with the solder during the brazing process, a layer of titanium is retained on the ceramic side of the ceramics and metal connection joints. The layer affects the wetting and reaction of the solder and the ceramic, and directly affects the connection strength between the ceramic and the metal. The presence of a large number of intermetallic compounds on the ceramic side of the joint increases the brittleness of the joint and is prone to cracking under the action of residual stress.

Therefore, in order to further expand the application range of ceramics, it is imperative to find out a convenient and quick preparation method of surface alloyed ceramics.

3. Contents of the invention

The purpose of the application method of the surface alloyed ceramics of the present invention is to use the existing ordinary ceramics to prepare surface alloyed ceramics. After the ordinary ceramics pass through the composite target and the process method designed in the present invention, the surface of the ordinary ceramics is permeated with a layer containing active metals. An alloy layer of titanium, zirconium or hafnium and one or more of the required metal materials iron, chromium, nickel, manganese, molybdenum, copper, aluminum or silver with the required composition and properties, and the surface alloyed ceramics on its surface It has metal properties such as electrical conductivity and thermal conductivity. On this basis, the surface alloyed ceramics are further used to achieve high-quality brazing connections between ceramics and metals.

The surface alloyed ceramics is characterized in that it uses a composite target to alloy the surface of ordinary ceramics in an arc-added glow furnace, so that the surface of ordinary ceramics is permeated with a layer containing active metals titanium, zirconium or hafnium and the required metals. One or more alloy layers of iron, chromium, nickel, manganese, molybdenum, copper, aluminum or silver, the surface of which has conductive and thermal conductive metal properties of surface alloyed ceramics.

The preparation method of the above-mentioned surface alloyed ceramics is characterized in that the composite target designed by the present invention is used to carry out surface alloying of ordinary ceramics in an arc-added glow furnace, the composite target evaporates or melts under the action of arc heat, and the metal ions are Under the action of a high electric field, it hits the ceramic surface at high speed, and is infiltrated on the ceramic surface through diffusion and chemical metallurgical reaction. The ceramic surface obtains an alloy layer composed of these metal elements. The preparation process parameters are: the ultimate vacuum degree is less than 6Pa, and the working pressure is 10 ～20Pa, working medium argon, glow voltage 300～900V, arc current 40～100A, infiltration time 10～50min, this method can realize the preparation of various types of surface alloyed ceramics and laminated composite materials.

The preparation method of the above-mentioned surface alloyed ceramics is characterized in that the composite target is made of active metal titanium, zirconium or hafnium and other required metal materials such as iron, chromium, nickel, manganese, molybdenum, copper, aluminum or silver. Or several kinds of mechanical combination in proportion. Calculated from the use area, the proportion of metal titanium, zirconium or hafnium is 10-40%, and the proportion of other metal elements is different due to different alloy components.

The application method of surface alloyed ceramics of the present invention is characterized in that it is a method of connecting surface alloyed ceramics and metals, and Si ₃ N ₄ , ZrO ₂ , Al ₂ prepared by the surface alloyed ceramics preparation method O ₃ or SiC surface alloyed ceramics are connected with aluminum foil, carbon steel or dissimilar ceramics after surface alloying, no flux is needed, and Ag-Cu solder is used. The process parameters are: ultimate vacuum degree is less than 6Pa, working pressure is 10 ～20Pa, glow voltage 300～900V, brazing temperature 750～900℃, holding time 5～15min, working medium argon, realize Si ₃ N ₄ , ZrO ₂ , Al ₂ O ₃ in arc-added glow furnace Or the connection between SiC surface alloyed ceramics and metal, the interface bonding strength is greater than 180MPa.

The purpose of preparing surface alloyed ceramics is to braze with metal materials. Special consideration can also be given to the selection of composite targets, such as choosing Cu and Ti binary composite targets or Ag, Cu and Ti ternary composite targets. Form Cu-Ti binary alloy or Ag-Cu-Ti ternary alloy, these two materials are good brazing filler metals in themselves, which is beneficial to the brazing connection of surface alloyed ceramics/metals. This not only saves solder, but also allows it to be brazed under various environmental conditions (atmospheric conditions).

The preparation method can also carry out surface alloying on both sides of the sheet-shaped ceramics, and can form double-sided alloyed ceramics. Double-sided alloyed ceramics can also be stacked and welded together to form a laminated composite material, as shown in Figure 5 of the accompanying drawings.

Compared with the existing ceramic metallization method and ceramic/metal brazing method, the preparation method has the following advantages:

1. It is conducive to the metallization and alloying of the ceramic surface, forming surface alloyed ceramics, and further broadening the application range of ceramics.

2. It avoids the influence of a single titanium infiltration layer and embrittlement, which is beneficial to the chemical reaction between the alloy layer and the ceramic, improves the interface bonding strength, and reduces the degree of interface stress concentration;

3. The composite alloy layer is not easy to be oxidized by the atmosphere.

4. The surface alloyed ceramics can be brazed under low vacuum conditions, even in the atmosphere; brazing with ordinary solder can obtain excellent welded joints.

5. The preparation speed is fast and the efficiency is high.

4. Description of drawings

Fig. 1 is a schematic diagram of arc-added glow vacuum furnace equipment used in the surface alloyed ceramics and the preparation method of the present invention. 1 is the cooling circulating water; 2 is the anode target, that is, the composite target; 3 is the furnace wall is in the form of a jacket, and the cooling water 1 is passed inside; 4 is the additional cathode, which plays the role of heating and heat preservation; 5 is the cathode pedestal; 6 is the sealing gasket; 7 Ceramic workpiece; 8 is an arc strike hook, which is used to ignite and maintain an arc; 9 is an arc power supply; 10 is a glow power supply.

Fig. 2 is a cross-sectional view of the structure of the composite metal target used in the surface alloyed ceramics and the preparation method of the present invention.

Fig. 3 is a bottom view of the composite metal target used in the surface alloyed ceramics and the preparation method of the present invention. According to different alloying components, materials 11, 12, 13, 14 can be titanium, zirconium or hafnium active element materials and one or one of iron, copper, nickel, chromium, manganese, aluminum, molybdenum, etc. Above, in general, from an economic point of view, the outermost ring is made of cheaper materials, and the innermost ring is made of expensive materials. For ceramic materials, active elements are indispensable, because they can carry out certain chemical reactions with ceramics. The proportions of materials 11, 12, 13, and 14 are calculated by area, and vary due to different ceramic materials and required alloy layer components.

Fig. 4 is a schematic diagram of the brazing method of the present invention. 15 is a surface alloyed ceramic, 16 is an alloy layer, 17 is a solder, and 18 is a metal (or a surface alloyed ceramic). Assemble the surface alloyed ceramics 15, solder 17 and metal 18, put them into a glow brazing furnace or a vacuum furnace, and then carry out brazing connection according to the above-mentioned process parameters.

Figure 5 is a ceramic/metal laminate composite. 19 is ceramic; 20 is metal material;

5. Specific implementation

Embodiment 1

Preparation of surface alloyed Al ₂ O ₃ ceramics for surface conductivity.

The ceramic is Al ₂ O ₃ , and the composite target adopts three components of titanium, copper and aluminum, which are arranged as copper, aluminum and titanium materials from outside to inside, and the area ratio is 30-40%, 30-40%, 20-40% . The process parameters of ceramic surface alloying are:

Ultimate vacuum degree 6Pa Glow voltage 600V

Arc current 60A Dipping time 30min

Working medium Argon

Al ₂ O ₃ ceramic surface alloy layer has a thickness of 20 μm and has good electrical conductivity.

Embodiment 2

Surface Alloyed Ceramics for Microjoints

The ceramic material is Al ₂ O ₃ , the metal is aluminum foil after 15 μm, the composite target is made of aluminum and titanium, the outer ring is aluminum, the inner ring is titanium, and the area ratio of aluminum and titanium in the composite target is 60-80%. , 20-40%. The surface alloyed ceramics are connected with metal and solder in a vacuum furnace.

The process parameters of ceramic surface alloying and brazing with metal are:

Ultimate vacuum degree 6Pa Working pressure 20Pa

Glow Voltage 700V Arc Current 60A

Dipping time 50min Brazing temperature 500℃

Holding time 10min working medium argon

Al ₂ O ₃ ceramic surface alloying layer thickness is 10 ~ 20μm, brazing results show that Al ₂ O ₃ ceramic/metal aluminum foil joints have no cracks, the entire joint surface has no disconnection, and the shear strength of the brazed joint is 100MPa.

Embodiment 3

Low vacuum brazing of surface alloyed ceramics to metals for ceramic/metal joints

The ceramic material is Si ₃ N ₄ , the metal material is carbon steel Q235, the composite target is composed of copper, titanium and iron, copper is used as the outer ring, titanium copper is used as the inner ring, and the area ratio of copper, titanium and iron is 40~ 60%, 20-40%, 10-40%, the surface alloyed ceramics and metals and Ag-Cu solder are placed in a vacuum furnace for brazing.

The process parameters of ceramic surface alloying and brazing with metal are:

Ultimate Vacuum 6Pa Working Pressure 20Pa

Glow Voltage 700V Arc Current 60A

Dipping time 50min Brazing temperature 850℃

Brazing vacuum degree 5×10 ^-2 Pa holding time 10min

Working medium Argon

The thickness of the alloy layer on the surface of the ceramic is 30 μm, the quality of the brazed joint is good, the Si ₃ N ₄ ceramic has no cracks, and the entire joint surface has no disconnection, and the shear strength of the brazed joint is 300 MPa.

Embodiment 4

Low-vacuum brazing after surface alloying of Si ₃ N ₄ and ZrO ₂ ceramics

The ceramics are Si ₃ N ₄ and ZrO ₂ . When Si ₃ N ₄ ceramics are surface alloyed, the composite target uses copper, titanium, and nickel as three elements. Copper is used as the outer ring, and nickel is used as the inner ring. The proportions of copper, titanium, and nickel are respectively 40-60%, 20-40%, 10-40%, when ZrO ₂ ceramic surface is alloyed, three elements of zirconium, chromium and nickel are used as the composite target, and the proportions of zirconium, chromium and nickel are 20-40%, 40% respectively. ～60%, 15～30%, the surface alloyed ceramic solder is put into a vacuum furnace for brazing. Its process parameters are:

Ultimate vacuum degree 6Pa Working pressure 20Pa

Glow Voltage 800V Arc Current 60A

Dipping time 40min Brazing temperature 930℃

Brazing vacuum degree 0.5Pa holding time 10min

Working medium Argon

The thickness of the alloy layer on the ceramic surface is 30 μm, and the joint with good performance is obtained as a result of brazing. The Si ₃ N ₄ and ZrO ₂ ceramic joint has no cracks, and the entire joint surface has no disconnection. The shear strength of the brazed joint is 230MPa.

Embodiment 5

Arc glow brazing of Al ₂ O ₃ ceramic surface to metal after alloying

The ceramic is Al ₂ O ₃ , the metal is carbon steel Q235B, the composite target uses four components of titanium, nickel and aluminum, and titanium is used as the outer ring, and the proportions of titanium, iron and aluminum are 20-40% and 20-40% respectively , 30-50%, the alloyed ceramics, metals and solders are put into a glow furnace for glow brazing. The process parameters of ceramic surface alloying and glow brazing with metal are:

Ultimate vacuum degree 6Pa Working pressure 20Pa

Glow Voltage 600V Arc Current 60A

Dipping time 40min Brazing temperature 900℃

Holding time 10min working medium argon

The thickness of the infiltrated layer on the surface of the ceramic is about 35 μm. As a result of brazing, a joint with good performance is obtained. The Al ₂ O ₃ ceramic has no cracks, and the entire joint surface has no disconnection. The shear strength of the brazed joint is 210MPa.

Embodiment 6

Brazing of ZrO ₂ Ceramic Surface Alloyed with Metal under Atmospheric Conditions

The ceramic is ZrO ₂ , the metal is carbon steel Q235B, the composite target uses three components of zirconium, iron and nickel, and nickel is used as the outer ring, and the proportions of zirconium, iron and nickel are 20-40%, 40-60%, respectively. 15-20%, the surface alloyed ceramics and metals are brazed under atmospheric conditions. The process parameters of ceramic surface alloying and brazing with metal are:

Ultimate vacuum degree 6Pa Working pressure 20Pa

Glow Voltage 700V Arc Current 60A

Dipping time 20min Brazing temperature 920℃

Holding time 10min working medium argon

The thickness of the infiltrated layer on the surface of the ceramic is about 30 μm. As a result of brazing, a joint with good performance is obtained. The ZrO ₂ ceramic has no cracks, and the entire joint surface has no disconnection. The shear strength of the brazed joint is 180 MPa.

Embodiment 7

Preparation of Al ₂ O ₃ Ceramic Laminates

The ceramic is flake Al ₂ O ₃ , the composite target uses titanium, copper, aluminum, and silver as four components, and copper is used as the outer ring, and the proportions of titanium, copper, aluminum, and silver are 20-40% and 40-60% respectively. , 15-20%, and 5-10% alloy the double-sided surfaces of sheet-shaped Al ₂ O ₃ , then stack three double-sided alloyed ceramics together and braze in a vacuum furnace.

The process parameters of ceramic surface alloying and brazing with metal are:

Ultimate vacuum degree 6Pa Working pressure 20Pa

Glow Voltage 700V Arc Current 60A

Dipping time 20min Brazing temperature 920℃

Holding time 10min working medium argon

Brazing vacuum degree 0.5Pa

The thickness of the infiltrated layer on the ceramic surface is about 40 μm, and there is no disconnection on the joint surface.

Claims (1)

1, a kind of application process of surface alloying ceramic is characterized in that it being the pottery behind a kind of surface alloying and the method for attachment of metal, the Si that adopts the surface alloying ceramic preparation method to make ₃N ₄, ZrO ₂, Al ₂O ₃Or the SiC surface alloying ceramic is connected with xenogenesis pottery behind aluminium foil, carbon steel or the surface alloying, do not need brazing flux, use the Ag-Cu solder, its technological parameter is: final vacuum is less than 6Pa, operating air pressure 10～20Pa, glow voltage 300～900V, 750～900 ℃ of brazing temperatures, temperature retention time 5～15min, working media argon gas, in the arc-added glow stove, realize Si ₃N ₄, ZrO ₂, Al ₂O ₃Or being connected of SiC surface alloying ceramic and metal, its interface bond strength is greater than 180MPa.

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