CN118324546B - A method for welding ceramics to metals - Google Patents

Abstract

The invention relates to the technical field of ceramic and metal welding, in particular to a method for welding between ceramic and metal, which comprises the following steps: s1: mixing oxide ceramic powder and metal powder according to different mass ratios to form three parts of mixed powder; s2: respectively adding ethanol into three parts of mixed powder, stirring, simultaneously adding activated carbon nano tube, electrolyte, polymethacrylic acid and surfactant, and ball-milling to form mixed powder slurry; s3: coating three parts of mixed powder slurry on the surface of oxide ceramic in sequence, pressing metal alloy on the upper surface of the slurry on the uppermost layer, and applying pressure of more than or equal to 0.5MPa to the sandwich structure; s4: electrifying and heating for the first time; s5: and electrifying and heating for the second time. The invention further eliminates the problems of pores and the like of the connecting layer by improving the gradient connecting layer, and greatly enhances the strength of the composite part.

Description

A method for welding ceramics to metals

Technical Field

The invention relates to the technical field of ceramic and metal welding, in particular to a method for welding ceramic and metal.

Background Art

Oxide ceramics have good high-temperature mechanical properties, anti-oxidation and corrosion resistance, but their high hardness and brittleness make them difficult to process. High-temperature alloys are relatively easy to process, but they have low melting points and relatively poor corrosion resistance. In practice, welding is often used to prepare ceramic-metal composite components. However, due to the large difference in the thermal expansion coefficients of ceramics and metals, the joint stress is large, which not only affects the strength of the joint, but also affects the thermal shock resistance of the joint. Although the use of metal brazing filler metals can also reduce joint stress, the melting point of metal brazing filler metals is low and they are not corrosion-resistant, which seriously restricts the performance of welded parts.

Therefore, a gradient mixed material of ceramic and metal is used as an intermediate layer to gradually transition the thermal expansion coefficient from the ceramic side to the metal side, effectively reducing the interface stress of ceramic-metal welding. However, since the difference between oxide ceramics and metal alloys is sometimes too large, and the sintering degree is not the same, it is difficult to control the expansion coefficient. After sintering, there is still the problem of too large pores and insufficient connection strength. Therefore, in response to the problems raised in the above background technology, those skilled in the art have proposed a method of actively adding electrolytes and carbon nanotubes to effectively eliminate the pores between the transition layers and further strengthen the strength of the oxide ceramic-metal alloy composite structure.

Summary of the invention

The object of the present invention is to provide a method for welding ceramics and metals to solve the problems mentioned in the above background technology.

To achieve the above object, the present invention provides the following technical solutions:

A method for welding ceramic to metal, comprising the following steps:

S1: mixing oxide ceramic powder and metal powder in different mass ratios to form three mixed powders, wherein the mass ratios of oxide ceramic powder and metal powder in the three mixed powders are R1, R2, and R3 respectively;

S2: adding ethanol to the three mixed powders obtained in step S1 respectively, stirring, adding activated carbon nanotubes, electrolyte, polymethacrylic acid and surfactant at the same time, ball milling for 1 hour, mixing evenly to form a mixed powder slurry;

S3: The three mixed powder slurries prepared in step S2 with different proportions are sequentially applied on the surface of the oxide ceramic in the order of decreasing proportion of oxide ceramic powder, and a metal alloy is pressed on the upper surface of the topmost slurry, the mixed powder slurry closest to the metal alloy has the smallest proportion of oxide ceramic powder, to form a sandwich structure, and a pressure of ≥0.5MPa is applied to the sandwich structure;

S4: preliminarily heating the sandwich structure prepared in step S3, the heating temperature is T1, a current of 10-100 mA/mm ² is applied during the heating process, and the heating time is t1;

S5: Continue to heat the sandwich structure preliminarily heated in step S4, the heating temperature is T2, during the heating process, apply the same current as in step S4, the heating time is t2, and after the heating is completed, a welded product is obtained.

Furthermore, in step S1, R ₁ >R ₂ >R ₃ , the range of R ₁ is (23.2:1)-(15.8:1), the range of R ₂ is (13.8:1)-(9.5:1), and the range of R ₃ is (8.8:1)-(1.5:1).

Furthermore, the oxide ceramic powder is one of YSZ, alumina, and barium titanate, and the metal powder is one of nickel, copper, titanium metal, and alloys thereof.

Furthermore, the mass ratio of the amount of ethanol used in each mixed powder in step S2 to the total amount of oxide ceramic powder and metal powder in the same portion is 1:1-2:1, the surfactant used in step S2 is one of ethyl dodecyl sulfonate, ethyl dodecyl phosphate, and ethyl dodecylphenol phosphate, and the mass ratio of the amount of surfactant in each mixed powder slurry to the amount of ethanol in the mixed powder slurry in the corresponding portion is 1:15-1:20.

Furthermore, the preparation method of the activated carbon nanotubes in step S2 is: ultrasonically disperse the carbon nanotubes in a mixed solution of concentrated nitric acid and concentrated sulfuric acid, heat to 45° C. in a water bath, stir and react for 1.5 hours, filter, wash with deionized water, and vacuum dry to obtain activated carbon nanotubes, wherein the mass concentration of concentrated nitric acid is 68wt%, the mass concentration of concentrated sulfuric acid is 98wt%, and the mass ratio of concentrated nitric acid to concentrated sulfuric acid is 2:3.

Furthermore, in step S2, the mass ratio of the amount of activated carbon nanotubes in each portion of the mixed powder slurry to the amount of ethanol in the corresponding portion of the mixed powder slurry is 1:10-1:16.

Furthermore, in step S2, the mass ratio of the amount of polymethacrylic acid in each portion of the mixed powder slurry to the amount of ethanol in the corresponding portion of the mixed powder slurry is 1:12-1:18.

Furthermore, the electrolyte in step S2 is one of sodium oxide and potassium oxide, and the mass ratio of the amount of electrolyte in each portion of the mixed powder slurry to the amount of ethanol in the corresponding portion of the mixed powder slurry is 1:14-1:22.

Furthermore, in the step S4, the temperature T1 is between 110-190° C., the temperature t1 is between 8-18 min, and in the step S5, the temperature T2 is between 800-1100° C., the temperature t2 is between 0.5-10 min.

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

1. The present invention completes the welding between oxide ceramic and metal alloy by gradient mixing and brushing between oxide ceramic powder and metal powder, which effectively alleviates the problem of reduced joint stress due to different expansion coefficients between oxide ceramic and metal alloy, and improves the strength between oxide ceramic and metal alloy.

2. The present invention actively adds electrolytes to the mixed powder slurry. Under the action of the electric field, the electrolytes form metal ions and oxygen ions that can actively migrate. The oxygen ions actively combine with the alloy metal to form oxides, further weakening the difference between the metal alloy and the oxide ceramic, while the metal ions (Na ⁺ , K ⁺ ) can form complex spherical oxides with the oxides. In addition, the present invention adds activated carbon nanotubes. The unique structure and conductivity of carbon nanotubes enhance the migration efficiency of oxygen ions and metal ions in the powder slurry.

3. The present invention forms a macromolecular carbon chain structure on the surface of the oxide through surfactants and macromolecular compounds, and cooperates with activated carbon nanotubes to form a composite structure between the carbon nanotubes and the oxide. Combined with the spherical oxides formed between the metal ions and the oxide, it can effectively eliminate the influence of the pores between the gradient connecting layers, further enhance the strength of the gradient layer, and improve the strength of the composite structure of ceramic powder and metal alloy.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a process flow chart of the present invention;

FIG2 is a schematic diagram of welding between oxide ceramic and alloy metal in the present invention;

FIG. 3 is a scanning electron microscope image of the sample near the interface in Example 1 of the present invention.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the present invention 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 to 3, the present invention provides:

A method for welding ceramics to metals, comprising the preparation of activated carbon nanotubes, specifically in the following manner:

The carbon nanotubes were ultrasonically dispersed in a mixed solution of concentrated nitric acid and concentrated sulfuric acid, heated to 45°C in a water bath, stirred for reaction for 1.5 hours, filtered, washed with deionized water, and vacuum dried to obtain activated carbon nanotubes. The mass concentration of concentrated nitric acid was 68wt%, the mass concentration of concentrated sulfuric acid was 98wt%, and the mass ratio of concentrated nitric acid to concentrated sulfuric acid was 2:3.

Example 1

A method for welding ceramic to metal, comprising the following steps:

S1: YSZ (yttria-stabilized zirconia) ceramic powder and nickel alloy powder are mixed into three parts of powder, and the weights of YSZ ceramic powder and nickel alloy powder in the three parts of powder are (139g and 6g), (244g and 18g), and (105g and 12g), respectively;

S2: Add (290 g, 524 g and 234 g) of ethanol to the three mixed powders obtained in step S1 respectively, and stir. At the same time, add (18.1 g, 32.7 g and 14.6 g) of activated carbon nanotubes, (16.1 g, 29.1 g and 13 g) of polymethacrylic acid, (13.1 g, 23.8 g, 10.6 g) of sodium oxide, and (14.5 g, 26.2 g, 11.7 g) of ethyl dodecyl sulfonate to the three mixed powders respectively, and ball mill for 1 hour to mix well to form a mixed powder slurry;

S3: The three mixed powder slurries with different proportions prepared in step S2 are sequentially brushed on the surface of the YSZ ceramic in the order of decreasing proportion of YSZ ceramic powder, and nickel alloy is pressed on the upper surface of the top mixed powder slurry. The mixed powder slurry close to the nickel alloy has the smallest proportion of YSZ ceramic powder to form a sandwich structure, and a pressure of 1 MPa is applied to the sandwich structure;

S4: preliminarily heating the sandwich structure prepared in step S3, the heating temperature is 110°C, a current of 100 mA/ ^mm2 is applied during the heating process, and the heating time is 18 min;

S5: Continue heating the sandwich structure after the preliminary heating in step S4, the heating temperature is 800°C, a current of 100 mA/ ^mm2 is applied during the heating process, and the heating time is 1 min to obtain a finished welding product.

Example 2

A method for welding ceramic to metal, comprising the following steps:

S1: YSZ ceramic powder and nickel alloy powder are mixed into three parts of powder, and the weights of YSZ ceramic powder and nickel alloy powder in the three parts of powder are (165g and 11g), (142g and 14g) and (151g and 48g) respectively;

S2: Add (176 g, 156 g and 199 g) of ethanol to the three mixed powders obtained in step S1 respectively, and stir. At the same time, add (17.6 g, 15.6 g and 19.9 g) of activated carbon nanotubes, (14.6 g, 13 g and 16.6 g) of polymethacrylic acid, (12.5 g, 11.1 g, 14.2 g) of sodium oxide, and (11.7 g, 10.4 g and 13.3 g) of ethyl dodecyl sulfonate to the three mixed powders respectively, and ball mill for 1 hour to mix well to form a mixed powder slurry;

S3: The three mixed powder slurries with different proportions prepared in step S2 are sequentially brushed on the surface of the YSZ ceramic in the order of decreasing proportion of YSZ ceramic powder, and nickel alloy is pressed on the upper surface of the top mixed powder slurry. The mixed powder slurry close to the nickel alloy has the smallest proportion of YSZ ceramic powder to form a sandwich structure, and a pressure of 1 MPa is applied to the sandwich structure;

S4: preliminarily heating the sandwich structure prepared in step S3 at a heating temperature of 180°C, applying a current of 70 mA/ ^mm2 during the heating process, and heating for 8 minutes;

S5: Continue heating the sandwich structure preliminarily heated in step S4, the heating temperature is 1000°C, a current of 70 mA/ ^mm2 is applied during the heating process, the heating time is 3 minutes, and a welding product is obtained.

Example 3

A method for welding ceramic to metal, comprising the following steps:

S1: YSZ ceramic powder and nickel alloy powder are mixed into three parts of powder, and the weights of YSZ ceramic powder and nickel alloy powder in the three parts of powder are (256g and 15g), (238g and 19g) and (285g and 44g) respectively;

S2: Add (406 g, 385 g and 493 g) of ethanol to the three mixed powders obtained in step S1 respectively, and stir. At the same time, add (36.9 g, 35 g and 44.8 g) of activated carbon nanotubes, (25.3 g, 24.1 g and 30.8 g) of polymethacrylic acid, (20.1 g, 19.6 g, 23.4 g) of sodium oxide, and (22.5 g, 21.3 g and 27.3 g) of ethyl dodecyl sulfonate to the three mixed powders respectively, and ball mill for 1 hour to mix well to form a mixed powder slurry;

S3: The three mixed powder slurries with different proportions prepared in step S2 are sequentially brushed on the surface of the YSZ ceramic in the order of decreasing proportion of YSZ ceramic powder, and nickel alloy is pressed on the upper surface of the top mixed powder slurry. The mixed powder slurry close to the nickel alloy has the smallest proportion of YSZ ceramic powder to form a sandwich structure, and a pressure of 1 MPa is applied to the sandwich structure;

S4: heating the sandwich structure prepared in step S3 at a temperature of 190°C, applying a current of 30 mA/ ^mm2 during the heating process, and heating for 10 min;

S5: Continue heating the sandwich structure preliminarily heated in step S4, the heating temperature is 900°C, a current of 30 mA/ ^mm2 is applied during the heating process, and the heating time is 2 minutes to obtain a finished welding product.

Example 4

A method for welding ceramic to metal, comprising the following steps:

S1: Alumina ceramic powder and titanium alloy powder are mixed into three parts of powder, and the weights of alumina ceramic powder and titanium alloy powder in the three parts of powder are (108g and 7g), (124g and 13g), and (116g and 48g), respectively;

S2: Add (184 g, 224 g and 262 g) of ethanol to the three mixed powders obtained in step S1 respectively, and stir. At the same time, add (15.3 g, 18.6 g and 21.8 g) of activated carbon nanotubes, (10.8 g, 13.2 g and 15.4 g) of polymethacrylic acid, (9.2 g, 11.2 g, 13.1 g) of potassium oxide, and (10.1 g, 12.5 g and 13.8 g) of dodecylphenol ethyl phosphate to the three mixed powders respectively, and ball mill for 1 hour, and stir to form a mixed powder slurry;

S3: The three mixed powder slurries with different proportions prepared in step S2 are sequentially applied on the surface of the alumina ceramic in the order of decreasing proportion of alumina ceramic powder, and titanium alloy is pressed on the upper surface of the top mixed powder slurry. The mixed powder slurry close to the titanium alloy has the smallest proportion of alumina ceramic powder to form a sandwich structure, and a pressure of 1 MPa is applied to the sandwich structure;

S4: preliminarily heating the sandwich structure prepared in step S3, the heating temperature is 110°C, a current of 80 mA/ ^mm2 is applied during the heating process, and the heating time is 16 min;

S5: Continue heating the sandwich structure preliminarily heated in step S4, the heating temperature is 1100°C, a current of 80 mA/ ^mm2 is applied during the heating process, and the heating time is 0.5 min to obtain a finished welding product.

Example 5

A method for welding ceramic to metal, comprising the following steps:

S1: Alumina ceramic powder and titanium alloy powder are mixed into three parts of powder, and the weights of alumina ceramic powder and titanium alloy powder in the three parts of powder are (121g and 8g), (136g and 12g), and (129g and 72g), respectively;

S2: Add (193 g, 218 g and 301 g) of ethanol to the three mixed powders obtained in step S1, respectively, and stir. Meanwhile, add (19.3 g, 20.8 g and 27.6 g) of activated carbon nanotubes, (12.1 g, 12.9 g and 17.7 g) of polymethacrylic acid, (9.6 g, 11.6 g and 14.3 g) of potassium oxide, and (12.1 g, 13.1 g and 15.8 g) of dodecylphenol ethyl phosphate to the three mixed powders, respectively, and ball mill for 1 hour, and stir to form a mixed powder slurry;

S3: The three mixed powder slurries with different proportions prepared in step S2 are sequentially applied on the surface of the alumina ceramic in the order of decreasing proportion of alumina ceramic powder, and titanium alloy is pressed on the upper surface of the top mixed powder slurry. The mixed powder slurry close to the titanium alloy has the smallest proportion of alumina ceramic powder to form a sandwich structure, and a pressure of 1 MPa is applied to the sandwich structure;

S4: preliminarily heating the sandwich structure prepared in step S3 at a heating temperature of 150°C, applying a current of 40 mA/ ^mm2 during the heating process, and heating for 18 min;

S5: Continue heating the sandwich structure preliminarily heated in step S4, the heating temperature is 800°C, a current of 40 mA/ ^mm2 is applied during the heating process, and the heating time is 10 minutes to obtain a finished welding product.

Example 6

A method for welding ceramic to metal, comprising the following steps:

S1: Alumina ceramic powder and copper alloy powder are mixed into three parts of powder, and the weights of alumina ceramic powder and copper alloy powder in the three parts of powder are (96g and 6g), (106g and 10g), and (92g and 21g), respectively;

S2: Add (185 g, 212 g and 203 g) of ethanol to the three mixed powders obtained in step S1, respectively, and stir. Meanwhile, add (18.5 g, 21.2 g and 20.3 g) of activated carbon nanotubes, (13.2 g, 15.1 g and 14.5 g) of polymethacrylic acid, (8.4 g, 10.1 g and 10.7 g) of sodium oxide, and (11.6 g, 13.2 g and 10.7 g) of ethyl dodecyl phosphate to the three mixed powders, respectively, and ball mill for 1 hour, and stir to form a mixed powder slurry;

S3: The three mixed powder slurries with different proportions prepared in step S2 are sequentially applied on the surface of the alumina ceramic in the order of decreasing proportion of alumina ceramic powder, and copper alloy is pressed on the upper surface of the top mixed powder slurry. The mixed powder slurry close to the copper alloy has the smallest proportion of alumina ceramic powder to form a sandwich structure, and a pressure of 1 MPa is applied to the sandwich structure;

S4: preliminarily heating the sandwich structure prepared in step S3 at a heating temperature of 140°C, applying a current of 50 mA/ ^mm2 during the heating process, and heating for 15 min;

S5: Continue heating the sandwich structure preliminarily heated in step S4, the heating temperature is 900°C, a current of 50 mA/ ^mm2 is applied during the heating process, and the heating time is 3 minutes to obtain a finished welding product.

Example 7

A method for welding ceramic to metal, comprising the following steps:

S1: barium titanate ceramic powder and titanium alloy powder are mixed into three parts of powder, and the weights of barium titanate ceramic powder and titanium alloy powder in the three parts of powder are (189g and 12g), (245g and 22g) and (146g and 97g) respectively;

S2: Add (345 g, 389 g and 316 g) of ethanol to the three mixed powders obtained in step S1 respectively, and stir. At the same time, add (26.5 g, 25.9 g and 22.5 g) of activated carbon nanotubes, (20.3 g, 21.6 g and 21.1 g) of polymethacrylic acid, (15.7 g, 18.5 g, 16.6 g) of potassium oxide, and (18.1 g, 22.9 g and 15.8 g) of ethyl dodecyl phosphate to the three mixed powders respectively, and ball mill for 1 hour, and stir to form a mixed powder slurry;

S3: The three mixed powder slurries with different proportions prepared in step S2 are sequentially applied on the surface of the barium titanate ceramic in the order of gradually decreasing proportion of the barium titanate ceramic powder, and titanium alloy is pressed on the upper surface of the top mixed powder slurry. The mixed powder slurry close to the titanium alloy has the smallest proportion of barium titanate ceramic powder to form a sandwich structure, and a pressure of 0.5 MPa is applied to the sandwich structure;

S4: preliminarily heating the sandwich structure prepared in step S3 at a heating temperature of 190°C, applying a current of 10 mA/ ^mm2 during the heating process, and heating for 16 min;

S5: Continue heating the sandwich structure preliminarily heated in step S4, the heating temperature is 1000°C, a current of 10 mA/ ^mm2 is applied during the heating process, the heating time is 8 minutes, and a welding product is obtained.

Comparative Example 1

The difference between Comparative Example 1 and Example 1 is that step S2 is changed by directly adding carbon nanotubes into step S2, and the remaining steps are exactly the same as those in Example 1.

Comparative Example 2

The difference between Comparative Example 2 and Example 1 is that step S2 is omitted, thereby eliminating the addition of electrolyte, and the remaining steps are exactly the same as those of Example 1.

Comparative Example 3

The difference between Comparative Example 3 and Example 1 is that step S2 is omitted, thereby eliminating the addition of polymethacrylic acid, and the remaining steps are exactly the same as those of Example 1.

Comparative Example 4

The difference between Comparative Example 4 and Example 1 is that step S2 is omitted, thereby completely eliminating the addition of activated carbon nanotubes, and the remaining steps are exactly the same as those of Example 1.

The performance of the finished ceramic welding products obtained in the above-mentioned Examples 1-7 and Comparative Examples 1-4 was tested, and the test data shown in Table 1 below were obtained:

Table 1: Performance test table of ceramic welding products obtained from Examples 1-7 and Comparative Examples 1-4

By comparing Example 1 and Comparative Examples 1-4 in Table 1 above, it can be seen that in the present application, after the activated carbon nanotubes are replaced with carbon nanotubes, the shear strength and Vickers hardness of the weld surface are significantly reduced. After the addition of electrolyte or polymethacrylic acid is cancelled, the shear strength and Vickers hardness of the weld surface are also significantly reduced. When the addition of carbon nanotubes is completely cancelled, the shear strength and Vickers hardness of the weld surface decrease most significantly.

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. A method for welding ceramics to metals, comprising the following steps: S1: mixing oxide ceramic powder and metal powder in different mass ratios to form three mixed powders, wherein the mass ratios of oxide ceramic powder and metal powder in the three mixed powders are R1, R2, and R3 respectively; S2: adding ethanol to the three mixed powders obtained in step S1 respectively, stirring, adding activated carbon nanotubes, electrolyte, polymethacrylic acid and surfactant at the same time, ball milling for 1 hour, mixing evenly to form a mixed powder slurry; S3: The three mixed powder slurries prepared in step S2 with different proportions are sequentially applied on the surface of the oxide ceramic in the order of decreasing proportion of oxide ceramic powder, and a metal alloy is pressed on the upper surface of the topmost slurry, the mixed powder slurry closest to the metal alloy has the smallest proportion of oxide ceramic powder, to form a sandwich structure, and a pressure of ≥0.5MPa is applied to the sandwich structure; S4: preliminarily heating the sandwich structure prepared in step S3, the heating temperature is T1, and during the heating process, a current of 10-100 mA/mm ² is applied, and the heating time is t1; S5: Continue heating the sandwich structure preliminarily heated in step S4, the heating temperature is T2, during the heating process, apply the same current as in step S4, the heating time is t2, and after the heating is completed, a welded product is obtained; The preparation method of the activated carbon nanotubes in step S2 is: ultrasonically dispersing the carbon nanotubes into a mixed solution of concentrated nitric acid and concentrated sulfuric acid, heating in a water bath to 45° C., stirring for reaction for 1.5 hours, filtering, washing with deionized water, and vacuum drying to obtain the activated carbon nanotubes, wherein the mass concentration of the concentrated nitric acid is 68wt%, the mass concentration of the concentrated sulfuric acid is 98wt%, and the mass ratio of the concentrated nitric acid to the concentrated sulfuric acid is 2:3; The mass ratio of the amount of activated carbon nanotubes in each portion of the mixed powder slurry in step S2 to the amount of ethanol in the corresponding portion of the mixed powder slurry is 1:10-1:16; The electrolyte in step S2 is one of sodium oxide and potassium oxide, and the mass ratio of the amount of electrolyte in each portion of the mixed powder slurry to the amount of ethanol in the corresponding portion of the mixed powder slurry is 1:14-1:22. 2. A method for welding ceramics to metals according to claim 1, characterized in that, in step S1, R ₁ >R ₂ >R ₃ , the range of R ₁ is (23.2:1)-(15.8:1), the range of R ₂ is (13.8:1)-(9.5:1), and the range of R ₃ is (8.8:1)-(1.5:1). 3. A method for welding ceramics to metals according to claim 1, characterized in that the oxide ceramic powder is one of YSZ, alumina, and barium titanate, and the metal powder is one of nickel, copper, titanium metal and alloys thereof. 4. A method for welding ceramics to metals according to claim 1, characterized in that the mass ratio of the amount of ethanol used in each mixed powder in the step S2 to the total amount of oxide ceramic powder and metal powder in the same portion is 1:1-2:1, the surfactant used in the step S2 is one of ethyl dodecyl sulfonate, ethyl dodecyl phosphate, and ethyl dodecylphenol phosphate, and the mass ratio of the amount of surfactant in each mixed powder slurry to the amount of ethanol in the mixed powder slurry in the corresponding portion is 1:15-1:20. 5. A method for welding ceramics to metals according to claim 1, characterized in that the mass ratio of the amount of polymethacrylic acid in each portion of the mixed powder slurry in step S2 to the amount of ethanol in the mixed powder slurry in the corresponding portion is 1:12-1:18. 6. A method for welding ceramics to metals according to claim 1, characterized in that in step S4, T1 is between 110-190°C, t1 is between 8-18 min, and in step S5, T2 is between 800-1100°C, t2 is between 0.5-10 min.