CN108118178A - A kind of in-situ synthesis of boride titanium-titanium carbide complex phase ceramic enhancing Cu-base composites and its preparation method and application - Google Patents

Abstract

The invention provides a method for in-situ synthesis of TiB ₂ -TiC multiphase ceramic reinforced copper-based composite material, comprising the following steps: ball milling titanium element and boron carbide to obtain a TiB ₂ -TiC multiphase ceramic precursor; Electroless nickel plating is carried out on the surface of the TiB ₂ -TiC multiphase ceramic precursor to obtain nickel wetting enhancement particles; the nickel wetting enhancement particles are mixed with a copper source to obtain a ball milling mixture; the ball milling mixture is carried out cold pressing to obtain a compact; sintering the compact in an oxygen-free atmosphere to obtain a sintered body; and forging the sintered body to obtain an in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material. The preparation method provided by the invention can prepare in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material with high hardness.

Description

An in-situ synthesized titanium boride-titanium carbide composite ceramic reinforced copper matrix composite material and Its preparation method and application

technical field

The invention belongs to the technical field of metal matrix composite materials, in particular to an in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material and its preparation method and application.

Background technique

Resistance spot welding is inseparable from the automobile production process. The production of passenger cars requires 3,000 welding points/car, and the production of cars requires 7,000-12,000 points/car; the cost of spot welding is calculated at 5 cents, and the spot welding cost of passenger cars reaches 150 US dollars, the spot welding cost of a car reaches 350-600 US dollars, accounting for 1/2-3/4 of the vehicle production cost, which prompts people to continuously study new spot welding electrode materials to reduce the cost of spot welding in the automobile production process .

During the spot welding process, the spot welding electrode will inevitably undergo plastic deformation under the action of mechanical force and heat. After the spot welding electrode undergoes plastic deformation, it will reduce the current density, reduce the Joule heat generated by the current, and eventually affect the solder joint. Quality, therefore, plastic deformation becomes one of the main factors of spot welding electrode failure. In order to suppress the plastic deformation of spot welding electrodes and prolong their service life, researchers applied components that can enhance the wear resistance of materials to the preparation of spot welding electrode materials.

TiC and TiB ₂ single-phase ceramics were earlier used as reinforcement phases for dispersion strengthening. Compared with pure copper materials, the wear resistance of composite materials reinforced by single-phase ceramics was improved, but the improvement effect was not satisfactory; later , the reinforcement phase gradually develops into composite ceramics, and TiB ₂ -TiC is a composite ceramic reinforcement phase that is widely used. In order to obtain TiB ₂ -TiC multiphase ceramics reinforced copper-based composites with excellent performance, researchers have proposed different preparation methods such as self-propagating high-temperature synthesis and mechanical alloying, such as directly mixing TiB ₂ and TiC into the copper matrix or TiB ₂ -TiC composite ceramic reinforced copper matrix composites were prepared by adding Ti and B ₄ C into the copper matrix. Although the above method can prepare a composite material with better wear resistance, its hardness performance still cannot meet the requirements of the spot welding electrode for the wear resistance of the material.

Contents of the invention

In order to solve the above problems, the present invention provides an in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material and its preparation method and application. The in situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix The composite material method can prepare a composite material with better wear resistance.

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

The invention provides a preparation method for in-situ synthesis of TiB ₂ -TiC multiphase ceramic reinforced copper-based composite material, comprising the following steps:

1) Ball mill titanium element and boron carbide to obtain TiB ₂ -TiC composite ceramic precursor;

2) performing electroless nickel plating on the surface of the TiB ₂ -TiC composite ceramic precursor to obtain nickel wetting enhancement particles;

3) mixing and ball milling the nickel wetting enhancing particles and the copper source to obtain a ball mill mixture;

4) cold pressing the ball-milled mixture to obtain a compact;

5) Sintering the compact in an oxygen-free atmosphere to obtain a sintered body;

6) Forging the sintered body to obtain an in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material.

Preferably, the molar ratio of the titanium element to boron carbide is 3:1.

Preferably, the speed of ball milling in the step 1) is 300-500r/min, and the time of ball milling is 12-24h.

Preferably, the temperature of the nickel plating solution used for electroless nickel plating in the step 2) is 45-50° C., and the pH value of the nickel plating solution is 9-11.

Preferably, the mass ratio of nickel wetting enhancing particles to copper source in step 3) is 0.5-5:95-99.

Preferably, the pressure of the step 4) cold pressing is 300-500MPa, and the time of cold pressing is 1-3min

Preferably, the sintering temperature in step 5) is 900-1050°C, and the sintering time is 10-30 minutes.

Preferably, the temperature of forging in step 6) is 500-550°C.

The present invention also provides an in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material prepared by the method described in the above technical scheme, including a TiB ₂ -TiC multiphase ceramic reinforcement phase, a copper matrix phase and a coating coated on the The nickel wetting phase on the surface of the TiB ₂ -TiC composite ceramic reinforcement phase, and the TiB ₂ -TiC composite ceramic reinforcement phase coated with the nickel wetting phase are dispersed in the interior and surface of the copper matrix phase.

The method for in-situ synthesizing TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material in the present invention comprises the following steps: performing ball milling on titanium element and boron carbide to obtain a TiB ₂ -TiC multiphase ceramic precursor; in the TiB ₂ - performing electroless nickel plating on the surface of the TiC multiphase ceramic precursor to obtain nickel wetting enhancement particles; mixing the nickel wetting enhancement particles with a copper source for ball milling to obtain a ball milling mixture; cold pressing the ball milling mixture, A compact is obtained; the compact is sintered in an oxygen-free atmosphere to obtain a sintered body; the sintered body is forged to obtain an in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material. In the present invention, nickel is firstly plated on the reinforced surface of TiB ₂ -TiC multiphase ceramics, and then combined with copper, the wettability between the reinforced phase and copper is improved by using nickel, and the binding force of the reinforced phase core matrix phase is improved, and the reinforced phase is The function provides favorable conditions, and then makes the obtained composite material have higher hardness and wear resistance. The results of the examples show that the hardness (HV _50g ) of the in-situ synthesized TiB ₂ -TiC multiphase ceramic-reinforced copper-based composite material prepared by the method of the present invention reaches above 258, and the service life of the electrode reaches above 1300 solder points.

Description of drawings

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is the metallographic photograph of the copper material that comparative example 1 prepares;

Fig. 2 is the metallographic photograph of the copper composite material that comparative example 2 prepares;

Fig. 3 is the metallographic photograph of the copper composite material that comparative example 3 prepares;

Fig. 4 is the metallographic photo of the in-situ synthesized TiB ₂ -TiC composite ceramic reinforced copper matrix composite material prepared in Example 1;

Fig. 5 is the metallographic photo of the in-situ synthesized TiB ₂ -TiC composite ceramic reinforced copper matrix composite prepared in Example 2;

Fig. 6 is the metallographic photo of the in-situ synthesized TiB ₂ -TiC composite ceramic reinforced copper matrix composite prepared in Example 3;

Fig. 7 is the metallographic photo of the in-situ synthesized TiB ₂ -TiC composite ceramic reinforced copper matrix composite prepared in Example 4;

Fig. 8 is the metallographic photo of the in-situ synthesized TiB ₂ -TiC composite ceramic reinforced copper matrix composite prepared in Example 5;

Fig. 9 is a front view of the spot welding electrode structure of the present invention;

Fig. 10 is a statistical graph of electrode life when the materials prepared in Comparative Examples 1-3 and Examples 1-5 are used as spot welding electrodes.

Detailed ways

The invention provides a preparation method for in-situ synthesis of TiB ₂ -TiC multiphase ceramic reinforced copper-based composite material, comprising the following steps:

1) Ball mill titanium element and boron carbide to obtain TiB ₂ -TiC composite ceramic precursor;

2) performing electroless nickel plating on the surface of the TiB ₂ -TiC composite ceramic precursor to obtain nickel wetting enhancement particles;

3) mixing and ball milling the nickel wetting enhancing particles and the copper source to obtain a ball mill mixture;

4) cold pressing the ball-milled mixture to obtain a compact;

5) Sintering the compact in an oxygen-free atmosphere to obtain a sintered body;

6) Forging the sintered body to obtain an in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material.

In the invention, titanium element and boron carbide are ball-milled to obtain a TiB ₂ -TiC composite ceramic precursor.

In the present invention, the titanium element is preferably provided in the form of titanium powder, and the particle size of the titanium powder is preferably 100-200 mesh, more preferably 120-200 mesh, and more preferably 140-170 mesh. In the present invention, the particle size of the boron carbide is preferably 200-400 mesh, more preferably 230-400 mesh. The present invention does not make any special limitation on the specific sources of titanium element and boron carbide, and commercially available products well known to those skilled in the art can be used. In the present invention, the purity of the titanium powder and boron carbide is preferably above 99.99%. The present invention preferably controls the particle size of the titanium element and the boron carbide to make the titanium and the boron carbide fully contact, so as to provide conditions for generating the TiB ₂ -TiC multiphase ceramic precursor.

In the present invention, the molar ratio of the titanium element to boron carbide is preferably 3:1; the present invention preferably avoids the formation of impurities by controlling the amount of titanium element and boron carbide, in order to obtain a multiphase ceramic precursor of TiB ₂ -TiC Offer favorable conditions.

In the present invention, the ball milling of the titanium element and boron carbide is preferably dry ball milling. In the present invention, the speed of the ball milling is preferably 300-500r/min, more preferably 350-450r/min; more preferably 360-420r/min; the time of the ball milling is preferably 12-24h, more preferably 16-22h, more preferably 18-20h. In the present invention, the ball-to-material ratio of the ball mill is preferably 10-30:1, more preferably 14-28:1, more preferably 18-26:1. In the present invention, the diameter of the balls for ball milling is preferably 5-10 mm, more preferably 5 mm. In the present invention, the material of the balls and the spherical pot of the ball mill is preferably alumina. In the present invention, the ball milling is preferably performed in an oxygen-free atmosphere, and the oxygen-free atmosphere is preferably argon. In the present invention, the purity of the argon is preferably greater than 99.9%. The present invention does not make any special limitation on the specific way of providing the oxygen-free atmosphere, and the methods known to those skilled in the art can be used. The present invention preferably limits the ball milling method to fully mix titanium and boron carbide in an oxygen-free atmosphere, avoiding the influence of oxygen on the raw material components, and providing favorable conditions for obtaining a TiB ₂ -TiC multiphase ceramic precursor with higher purity .

In the present invention, the TiB ₂ -TiC multi-phase ceramic precursor precursor is a metastable titanium carbon-titanium boride compound composed of Ti, C and B elements, and has poor physical stability. The TiB ₂ -TiC multi-phase ceramic reinforcement phase that undergoes phase change in the middle and becomes stable provides the possibility for the in-situ synthesis of TiC-reinforced copper matrix composites.

After the TiB ₂ -TiC multiphase ceramic precursor is obtained, the present invention performs electroless nickel plating on the surface of the TiB ₂ -TiC multiphase ceramic precursor to obtain nickel wetting enhancement particles. The present invention does not make any special limitation on the amount of nickel in the nickel wetting enhancement particles, subject to nickel being able to coat the TiB ₂ -TiC multiphase ceramic precursor; the present invention defines the coating thickness of the nickel wetting phase Do not make any special restrictions. In the present invention, the electroless nickel plating preferably comprises the following steps:

After mixing the TiB ₂ -TiC multiphase ceramic precursor with the nickel plating solution, the electroless nickel plating reaction is carried out to obtain the mixed material solution;

The mixed material liquid is filtered, washed and dried in sequence to obtain nickel wettability enhancing particles.

In the present invention, the temperature of the nickel plating solution is preferably 40-50°C, more preferably 42-48°C, and more preferably 45°C. The present invention does not make any special limitation on the temperature control method of the nickel plating solution, and the control method well known to those skilled in the art can be adopted. The present invention does not make any special limitations on the components and preparation methods of the nickel plating solution, and those well-known by those skilled in the art can be used. The invention controls the temperature of the nickel plating solution, can control the rate of the electroless nickel plating in an appropriate range, and ensures that the nickel wetting phase can be evenly coated on the surface of the TiB ₂ -TiC composite ceramic precursor.

In the present invention, the pH value of the nickel plating solution is preferably 9-11, more preferably 9.5-10.5. The present invention does not make any special limitation on the pH adjustment method of the nickel plating solution, as long as the nickel plating solution is within the above pH range. In the present invention, the pH of the nickel plating solution is limited as above, and the rate of the electroless nickel plating is effectively controlled in conjunction with the temperature conditions, so that the nickel can uniformly coat the surface of the TiB ₂ -TiC composite ceramic precursor.

The present invention does not make any special limitation on the time of the electroless nickel plating reaction, and the electroless nickel plating reaction can be stopped without bubbles in the mixed material liquid. In the present invention, the electroless nickel plating reaction is preferably carried out under stirring conditions. The present invention does not make any special limitations on the specific implementation of the stirring, and it is enough to use those well-known by those skilled in the art. In the present invention, the stirring is preferably magnetic stirring. In the present invention, the TiB ₂ -TiC composite ceramic precursor is mixed with the nickel plating solution, and the nickel element formed by the reaction of the nickel salt component and the reducing agent in the nickel plating solution is coated on the TiB ₂ -TiC composite ceramic under stirring conditions The surface of the precursor, and then obtain the mixed material liquid containing nickel wetting enhancement particles.

After the mixed material liquid is obtained, in the present invention, the mixed material liquid is preferably filtered, washed and dried in sequence to obtain nickel wet precursor particles. The present invention does not make any special limitations on the specific implementation of the filtering, and it is enough to use those well-known by those skilled in the art. The present invention does not make any special limitation on the washing, and the method well known to those skilled in the art can be used. In the present invention, the drying method is preferably natural drying or vacuum drying. In the present invention, the natural drying is preferably carried out in air; the natural drying time is preferably 24-48 hours, more preferably 30-45 hours; the natural drying temperature is preferably room temperature. In the present invention, the vacuum degree of the vacuum drying is preferably 0.8×10 ^-2 ~ 1.2×10 ^-2 MPa, more preferably 1.0×10 ^-2 MPa; the vacuum drying temperature is preferably 90-110°C, More preferably, it is 95-100° C.; the time for vacuum drying is preferably 18-24 hours, more preferably 20-22 hours.

In the present invention, the filtering, washing and drying treatment can remove the nickel salt, reducing agent and water impurities on the surface of the nickel-wetting precursor particle, provide favorable conditions for the subsequent full mixing with the copper source, and avoid the generation of impurities.

After the nickel-wetting precursor particles are obtained, the present invention mixes the nickel-wetting precursor particles with a copper source and ball mills to obtain a ball-milling mixture. In the present invention, the mass ratio of nickel wet precursor particles to copper source in the ball mill mixture is preferably 0.5-5:95-99, more preferably 0.5-3:97-99. In the present invention, the copper source is preferably copper element; the copper element is preferably provided in the form of copper powder. In the present invention, the purity of the copper powder is preferably 97-99.9%, more preferably 99.9%. In the present invention, there is no special requirement on the particle size of the copper powder, and the ones known to those skilled in the art can be used. In the present invention, the particle size of the copper powder is preferably 100-200 mesh, more preferably 120-200 mesh. The present invention does not impose any special limitation on the specific mixing method, and the methods well known to those skilled in the art can be used.

In the present invention, the mixing ball milling speed of the nickel wet precursor particles and the copper source is preferably 120-240r/min, more preferably 150-220r/min, more preferably 180-200r/min; the mixing ball milling The time is preferably 8-12h, more preferably 9-11h, more preferably 10h. In the present invention, the ball-to-material ratio of the mixing ball mill is preferably (2-10):1, more preferably (5-10):1. In the present invention, the mixed ball milling of the nickel wet precursor particles and the copper source is preferably wet ball milling, and the medium of the wet ball milling is preferably absolute ethanol. The present invention does not make any special regulations on the specific amount of the ball milling medium, and the amount well known to those skilled in the art can be used. In the present invention, the material of the balls and the spherical pot for ball milling of the mixture of nickel wetting enhancing particles and copper source is preferably alumina. In the present invention, ball milling is preferably performed on the mixture of nickel wetting enhancing particles and copper source, so that the nickel wetting enhancing particles can fully contact and diffuse with copper, and provide favorable conditions for obtaining a composite material with uniformly distributed reinforcing phases.

After the mixing and ball milling, the present invention preferably dries the ball milled material to obtain a ball milling mixture. In the present invention, the drying is preferably vacuum drying. In the present invention, the vacuum degree of the vacuum drying is preferably ≥1×10 ^-2 MPa, more preferably 0.01-0.1 MPa, further preferably 0.05-0.1 MPa, more preferably 0.08-0.1 MPa; the vacuum drying The temperature is preferably 80-100°C, more preferably 85-100°C, more preferably 90-100°C; the vacuum drying time is preferably 12-24h, more preferably 15-24h. The invention removes the absolute ethanol in the ball-milled material through vacuum drying, and reduces the influence of residual ethanol on the forming effect of the ball-milled mixture.

After the ball-milling mixture is obtained, the present invention cold-presses the ball-milling mixture to obtain a compact. In the present invention, the pressure of the cold pressing is preferably 300-500 MPa, more preferably 350-450 MPa; the time of the cold pressing is preferably 1-3 min, more preferably 1.5-2.5 min. In the present invention, the temperature of the cold pressing is preferably room temperature. In the present invention, the cold pressing is preferably accomplished by means of two-way pressing; the present invention has no special requirements for the specific implementation of the two-way pressing, and implementations well known to those skilled in the art can be used. The invention utilizes cold pressing to form the dispersed mixture, and at the same time makes each component of the ball-milled mixture dense and compact, thereby improving the density of the finally prepared in-situ synthesized TiB ₂ -TiC reinforced copper-based composite material. In the present invention, the diameter of the compact is preferably 40mm; the aspect ratio of the compact is preferably (1.8-2.2):1, more preferably 2:1; the relative density of the compact is preferably 99.4 ~99.8%.

After the compact is obtained, the present invention sinters the compact in an oxygen-free atmosphere to obtain a sintered body. In the present invention, the oxygen-free atmosphere is preferably an argon atmosphere. In the present invention, the flow rate of the argon gas is preferably 1-3 L/min, more preferably 3 L/min. In the present invention, the sintering temperature is preferably 900-1050° C., more preferably 1000-1050° C.; the sintering time is 10-30 minutes; more preferably 15-25 minutes. In the present invention, the heating rate to the sintering temperature is preferably 10-15°C/min, more preferably 10°C/min. The present invention does not make any special limitation on the specific implementation of the sintering, and the ones well-known to those skilled in the art can be used.

The present invention further provides conditions for the alloying reaction of each component in the compact by limiting the sintering conditions to the above range; during the sintering process, nickel-wetting precursor particles undergo an alloying reaction to generate _TiB2 coated with nickel on the surface - TiC multiphase ceramic reinforcement phase, providing a suitable sintered body for obtaining the target product.

After the sintered body is obtained, the present invention forges the sintered body to obtain in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material. The invention improves the hardness performance of the TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material through forging. In the present invention, the relative density of the in-situ synthesized TiB ₂ -TiC multiphase ceramic-reinforced copper-based composite material is preferably above 95%, more preferably 96-99.5%, and more preferably 98.0-99.4%.

In the present invention, the deformation of the forging in the longitudinal direction is preferably 100-300%, more preferably 200-300%; the deformation in the diameter direction is preferably 40-50%, more preferably 50%. In the present invention, the temperature of the forging is preferably 500-550°C, more preferably 510-540°C. The present invention does not make any special limitation on the specific implementation of the forging, and it is enough to use the methods well known by those skilled in the art to realize the control of the above-mentioned deformation and relative density. In the present invention, the number of forging presses is preferably 5 to 10 times, more preferably 10 times.

The present invention also provides an in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material prepared by the method described in the above technical solution, including a TiB ₂ -TiC multiphase ceramic reinforcement phase, a copper matrix phase and a coating coated on the The nickel wetting phase on the surface of the TiB ₂ -TiC composite ceramic reinforcement phase is described, and the TiB ₂ -TiC composite ceramic reinforcement phase coated with the nickel wetting phase is dispersed inside and on the surface of the copper matrix phase.

In the present invention, the mass ratio of the TiB ₂ -TiC multiphase ceramic reinforcement phase to the copper matrix phase in the in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material is preferably 0.5-2:48-49.5, further Preferably it is 0.5-1.5:48.5-49.5.

In the present invention, the hardness (HV _50g ) of the in-situ synthesized TiB ₂ -TiC composite ceramic reinforced copper matrix composite material is preferably above 255, more preferably 258-293; the in-situ synthesized TiB ₂ -TiC composite The electrode service life of the phase ceramic reinforced copper matrix composite material is preferably more than 1300 welding points, more preferably 1400 to 2900 welding points; the conductivity of the in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material is preferably 82 % or more, more preferably 82.7 to 89.9.

The present invention also provides the application of the multi-step in-situ synthesis of TiB ₂ -TiC multiphase ceramic reinforced copper-based composite material described in the above technical solution as a spot welding electrode material, and the multi-step in-situ synthesis of TiB ₂ -TiC The multiphase ceramic reinforced copper matrix composite material is sequentially machined and cold extruded to obtain the spot welding electrode material.

The present invention does not have any special requirements on the geometric dimensions of the TiB ₂ -TiC spot welding electrodes synthesized in situ by the multi-step method, and those well-known by those skilled in the art can be used. In the present invention, the structural front view of the spot welding electrode is shown in FIG. 9 . The present invention does not make any special limitations on the specific implementation of the machining and cold extrusion, as long as the electric welding electrode with the above structure can be obtained. The present invention does not make any special limitation on the specific dimensions of the spot welding electrodes, and those well-known by those skilled in the art can be used. In the present invention, the geometric dimensions of the spot welding electrodes are as shown in Figure 9 (in mm).

In order to further illustrate the present invention, the in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper-based composite material provided by the present invention and its preparation method and application will be described in detail below in conjunction with the examples and accompanying drawings, but they should not be understood as an explanation of the present invention. Limitation of the scope of protection.

Comparative example 1

The pure copper powder with a particle size of 200 mesh is pressed in two directions, and the pressure is kept at 350MPa for 2 minutes. The diameter of the compact is 40mm, and the aspect ratio of the compact is 1:2. The compact was sintered at 950° C. under an argon atmosphere with a flow rate of 2 L/min, and the holding time was 30 minutes. Under the condition that the single deformation is controlled to be less than 10%, the sintered compact is repeatedly forged at 550°C for 10 times, and the final deformation in the diameter direction is 50%, and the deformation in the longitudinal direction is 300%. After treatment, copper spot welding is obtained. electrode material. The diameter of the material is 20mm, the length is 40mm, the relative density is 99.2%, and the metallographic structure is shown in Figure 1.

The processed copper spot welding electrode material is processed into a spot welding electrode with the shape and geometric dimensions (in mm) shown in FIG. 9 through machining and subsequent cold extrusion process. According to the IACS standard test comparative example 1, the electrical conductivity of the spot welding electrode prepared by the copper spot welding electrode material, the test results are shown in Table 1; according to the metal material Vickers hardness test standard GB/T 4340.1-2009 test the hardness performance of the material obtained in comparative example 1 , the test results are shown in Table 1; according to the AWS-W-6858A standard to test the service life of the spot welding electrode prepared from the material of Comparative Example 1, the test results are shown in Table 1 and Figure 10.

Comparative example 2

The particle size is 200 mesh titanium element (Ti powder, purity ≥99.99%), boron carbide (B ₄ C, purity ≥99.99%) and pure copper powder are mechanically ball milled, the molar ratio of titanium powder to boron carbide is 3:1, Titanium powder and boron carbide account for 1% of the total mass of raw materials, and the mass fraction of copper powder in the total raw materials is 99%. The ball milling process is a speed of 400r/min, a ball milling time of 24 hours, and a ball-to-material ratio of 20:1. The material of the balls and the ball tank is alumina, and the diameter of the balls is 5mm. The ball milling process is completed under the protection of argon gas. Greater than 99.9%. The ball-milled powder is pressed in two directions and kept under pressure of 500 MPa for 3 minutes. The diameter of the green compact is 40 mm, and the length-to-diameter ratio of the green compact is 1:2. In an argon environment with a flow rate of 3L/min, the temperature was raised to 1050°C at a heating rate of 10°C/min, and the holding time was 30min. Under the condition that the single deformation is controlled to be less than 10%, the sintered compact is repeatedly forged at 550°C for 10 times, and the final deformation in the diameter direction is 50%, and the deformation in the longitudinal direction is 300%, and the copper composite material is obtained after treatment. , the diameter is 20mm, the length is 40mm, the relative density is 99.1%, and the metallographic structure is shown in Figure 2.

The copper composite material obtained after the treatment was processed into a spot welding electrode with the shape and size shown in FIG. 9 according to the method of Comparative Example 1. The performance test method is the same as that of Comparative Example 1, and the test results are shown in Table 1 and Figure 10.

Comparative example 3

Weigh 0.5g of TiB ₂ -TiC powder with a particle size of 200 mesh (TiB ₂ : TiC molar ratio 2:1), and 49.5g of pure copper powder at a ball milling speed of 200r/min, a ball milling time of 10h, and a ball-to-material ratio of 10:1 , fully mixed in an anhydrous ethanol soaking environment, the material of the grinding ball and the spherical tank is alumina, and the diameter of the grinding ball is 5mm. The ball-milled powder was dried at 95°C for 24 hours in an environment with a vacuum degree greater than 1×10 ^-2 MPa. The vacuum-dried powder was subjected to two-way pressure and kept at 500 MPa for 3 minutes, and the diameter of the green compact was 40 mm. The formed compact was sintered in an argon-protected environment (the gas flow rate was 3 L/min), the sintering temperature was 1050° C., and the sintering time was 30 minutes. Under the condition that the single deformation is controlled to be less than 10%, the sintered compact is repeatedly forged at 550°C for 10 times, and the final deformation in the diameter direction is 50%, and the deformation in the longitudinal direction is 300%, and the copper composite material is obtained after treatment. Material.

The obtained copper composite material has a diameter of 20 mm, a length of 40 mm, a relative density of 99.2%, and a metallographic structure as shown in FIG. 3 . The copper composite material obtained after the treatment was processed into a spot welding electrode with the shape and size shown in FIG. 9 according to the method of Comparative Example 1. The performance test method is the same as that of Comparative Example 1, and the test results are shown in Table 1 and Figure 10.

Example 1

Weigh 10g of titanium powder and boron carbide (the molar ratio of titanium powder and boron carbide is 3:1, the particle size is 200 mesh, and the purity is ≥99.99%) for ball milling. The material ratio is 10:1, the material of the grinding ball and the spherical tank is alumina, and the diameter of the grinding ball is 5mm. The ball milling process is completed under the protection environment of argon gas, and the purity of the argon gas is 99.9%. Put the ball-milled titanium powder and boron carbide powder into an electroless nickel plating solution with a pH value of 9, and stir the solution with a magnetic stirrer at a temperature of 40°C until no bubbles are generated, then filter and wash with deionized water until neutral , placed in the air to dry naturally for later use. Take 0.5g of dried ball-milled powder, and mix it with 49.5g of pure copper powder with a particle size of 200 mesh at a ball-milling speed of 120r/min, a ball-milling time of 12h, a ball-to-material ratio of 2:1, and fully mix in an anhydrous ethanol soaking environment , The material of the grinding ball and the spherical tank is alumina, and the diameter of the grinding ball is 5mm. The powder after ball milling was vacuum-dried, the vacuum degree was 1×10 ^-2 MPa, the drying temperature was 90° C., and the drying time was 12 hours. The vacuum-dried powder was subjected to two-way pressure and kept at 300 MPa for 3 minutes, and the diameter of the green compact was 40 mm. The formed compact was sintered in an argon-protected environment (the gas flow rate was 2 L/min). During sintering, the temperature was raised to 950 °C at a rate of 10 °C/min, and then kept for 20 min to obtain a sintered body; The secondary deformation is less than 10%. Under the condition of 550°C, the sintered body is repeatedly forged 10 times, and the final deformation in the diameter direction is 50%, and the deformation in the longitudinal direction is 300%. After treatment, in-situ synthesized TiB ₂ -TiC composite ceramics are obtained Reinforced copper matrix composites.

The in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite has a diameter of 20mm, a length of 40mm, and a relative density of 98.2%. The metallographic structure is shown in Figure 4. The in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material was processed into a spot welding electrode according to the method of Comparative Example 1. The performance test method is the same as that of Comparative Example 1, and the test results are shown in Table 1 and Figure 10.

Example 2

Weigh 10g of titanium powder and boron carbide (the molar ratio of titanium powder and boron carbide is 3:1, the particle size is 200 mesh, and the purity is ≥99.99%) for ball milling. The material ratio is 20:1, the material of the grinding ball and the spherical tank is alumina, the diameter of the grinding ball is 5mm, the ball milling process is completed under the protection of argon, and the purity of the argon is 99.95%. Put the ball-milled titanium powder and boron carbide powder into an electroless nickel plating solution with a pH value of 9.5, and stir the solution with a magnetic stirrer at a temperature of 45°C until no bubbles are generated, then filter and wash with deionized water until neutral , placed in the air to dry naturally. Take 0.5g of dried ball-milled powder, and mix it with 49.5g of pure copper powder with a particle size of 200 mesh at a ball-milling speed of 150r/min, a ball-milling time of 8h, a ball-to-material ratio of 5:1, and fully mix in an anhydrous ethanol soaking environment , The material of the grinding ball and the spherical tank is alumina, and the diameter of the grinding ball is 5mm. The ball-milled powder was dried at 95°C for 18 hours in an environment with a vacuum degree greater than 1×10 ^-2 MPa. The vacuum-dried powder was subjected to two-way pressure and kept at 400 MPa for 3 minutes, and the diameter of the green compact was 40 mm. The molded compact was sintered in an argon-protected environment (the gas flow rate was 3 L/min), the heating rate was controlled at 10°C/min, the temperature was raised to 1000°C, and sintered for 30 minutes to obtain a sintered body. Under the condition of controlling the single deformation less than 10% and 550℃, the sintered body was repeatedly forged 10 times, and the final deformation in the diameter direction was 50%, and the deformation in the longitudinal direction was 300%. After the treatment, the in-situ synthesized TiB ₂ - TiC composite ceramics reinforced copper matrix composites.

The in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite has a diameter of 20mm, a length of 40mm, and a relative density of 98.6%. The metallographic structure is shown in Figure 5. The in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material was processed into a spot welding electrode according to the method of Comparative Example 1. The performance test method is the same as that of Comparative Example 1, and the test results are shown in Table 1 and Figure 10.

Implementation column 3

Weigh 10g of titanium powder and boron carbide (the molar ratio of titanium powder and boron carbide is 3:1, the particle size is 200 mesh, and the purity is ≥99.99) for ball milling. The ratio is 30:1, the material of the grinding ball and the spherical tank is alumina, the diameter of the grinding ball is 5mm, the ball milling process is completed under the protection environment of argon, and the purity of the argon is greater than 99.9%. Put the ball-milled titanium powder and boron carbide powder into an electroless nickel plating solution with a pH value of 9.5, and stir the solution with a magnetic stirrer at a temperature of 50°C until no bubbles are generated, then filter and wash with deionized water until neutral , placed in the air to dry naturally for later use. Take 0.5g of dried ball-milled powder, and mix it with 49.5g of pure copper powder with a particle size of 200 mesh at a ball-milling speed of 200r/min, a ball-milling time of 10h, a ball-to-material ratio of 10:1, and soak in anhydrous ethanol. , The material of the grinding ball and the spherical tank is alumina, and the diameter of the grinding ball is 5mm. The ball-milled powder is dried at 100°C for 24 hours in an environment with a vacuum degree greater than 1×10 ^-2 MPa. The vacuum-dried powder was subjected to two-way pressure and kept at 500 MPa for 3 minutes, and the diameter of the green compact was 40 mm. The shaped compact was sintered in an argon-protected environment (the gas flow rate was 3 L/min), the temperature was raised to 1050° C. at a rate of 15° C./min, and the temperature was kept for 30 minutes to obtain a sintered body. Under the condition that the single deformation is controlled to be less than 10% and the temperature is 550°C, the sintered body is repeatedly forged 10 times, and the final deformation in the diameter direction is 50%, and the deformation in the longitudinal direction is 300%. After processing, in-situ synthesis is obtained. TiB ₂ -TiC composite ceramics reinforced copper matrix composites.

The in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite has a diameter of 20mm, a length of 40mm, and a relative density of 99.6%. The metallographic structure is shown in Figure 6. The in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material was processed into a spot welding electrode according to the method of Comparative Example 1. The performance test method is the same as that of Comparative Example 1, and the test results are shown in Table 1 and Figure 10.

Example 4

Weigh 10g of titanium powder and boron carbide (the molar ratio of titanium powder and boron carbide is 3:1, the particle size is 200 mesh, and the purity is ≥99.99) for ball milling. The ratio is 30:1, the material of the grinding ball and the spherical tank is alumina, the diameter of the grinding ball is 5mm, the ball milling process is completed under the protection environment of argon, and the purity of the argon is greater than 99.9%. Put the ball-milled titanium powder and boron carbide powder into an electroless nickel plating solution with a pH value of 9.5, and stir the solution with a magnetic stirrer at a temperature of 50°C until no bubbles are generated, then filter and wash with deionized water until neutral , placed in the air to dry naturally. Take 1 g of the dried ball-milled powder, and mix it with 49 g of pure copper powder with a particle size of 200 mesh at a ball milling speed of 200 r/min, a ball milling time of 10 h, a ball-to-material ratio of 10:1, and soak in anhydrous ethanol. The material of the ball and the spherical tank is alumina, and the diameter of the grinding ball is 5mm. The ball-milled powder is dried at 100°C for 24 hours in an environment with a vacuum degree greater than 1×10 ^-2 MPa. The vacuum-dried powder was subjected to two-way pressure and kept at 500 MPa for 3 minutes, and the diameter of the green compact was 40 mm. The shaped compact was sintered in an argon-protected environment (the gas flow rate was 3 L/min), the temperature was raised to 1050° C. at a rate of 15° C./min, and the temperature was kept for 30 minutes to obtain a sintered body. Under the condition that the single deformation is controlled to be less than 10% and the temperature is 550°C, the sintered body is repeatedly forged 10 times, and the final deformation in the diameter direction is 50%, and the deformation in the longitudinal direction is 300%. After processing, in-situ synthesis is obtained. TiB ₂ -TiC composite ceramics reinforced copper matrix composites.

The in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material has a diameter of 20mm, a length of 40mm, and a relative density of 98.9%. The metallographic structure is shown in Figure 7. The in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material was processed into a spot welding electrode according to the method of Comparative Example 1. The performance test method is the same as that of Comparative Example 1, and the test results are shown in Table 1 and Figure 10.

Example 5

Weigh 10g of titanium powder and boron carbide (the molar ratio of titanium powder and boron carbide is 3:1, the particle size is 200 mesh, and the purity is ≥99.99) for ball milling. The ratio is 30:1, the material of the grinding ball and the spherical tank is alumina, the diameter of the grinding ball is 5mm, the ball milling process is completed under the protection environment of argon, and the purity of the argon is greater than 99.9%. Put the ball-milled titanium powder and boron carbide powder into an electroless nickel plating solution with a pH value of 9.5, and stir the solution with a magnetic stirrer at a temperature of 50°C until no bubbles are generated, then filter and wash with deionized water until neutral , placed in the air to dry naturally. Take 1.5g of dried ball-milled powder and mix it with 48.5g of pure copper powder with a particle size of 200 mesh at a ball-milling speed of 200r/min, a ball-milling time of 10h, a ball-to-material ratio of 10:1, and soak in anhydrous ethanol. , The material of the grinding ball and the spherical tank is alumina, and the diameter of the grinding ball is 5mm. The ball-milled powder is dried at 100°C for 24 hours in an environment with a vacuum degree greater than 1×10 ^-2 MPa. The vacuum-dried powder was subjected to two-way pressure and kept at 500 MPa for 3 minutes, and the diameter of the green compact was 40 mm. The formed compact was sintered in an argon-protected environment (the gas flow rate was 3 L/min), and the temperature was raised to 1050° C. at a rate of 15° C./min, and held for 30 minutes to obtain a sintered body. Under the conditions of controlling the single deformation to be less than 10% and the temperature at 550°C, the sintered body is repeatedly forged 10 times, and the final deformation in the diameter direction is 50%, and the deformation in the longitudinal direction is 300%. After treatment, in-situ synthesis TiB ₂ -TiC composite ceramics reinforced copper matrix composites.

The in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material has a diameter of 20 mm, a length of 40 mm, and a relative density of 98.0%. The metallographic structure is shown in FIG. 8 . The in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material was processed into a spot welding electrode according to the method of Comparative Example 1. The performance test method is the same as that of Comparative Example 1, and the test results are shown in Table 1 and Figure 10.

Fig. 1 is the metallographic structure diagram of the copper material obtained in comparative example 1, and the organizational structure is relatively uniform; Fig. 2 is the metallographic structure diagram of the copper-based composite material obtained in comparative example 2, wherein the black part is an agglomeration-enhanced phase, illustrating that comparative example 2 provides The homogeneity of the microstructure obtained by the method is relatively poor, and the hardness performance of the product is affected; Fig. 3 is the metallographic structure diagram of the copper composite material prepared in Comparative Example 3, and it can be found from the figure that the agglomeration problem of the reinforcing phase is relatively higher than that of Comparative Example 2 Although it has decreased, it still exists; it is also known from the metallographic structure diagrams of Comparative Examples 2 and 3 that in the absence of a wetting phase, the reinforced phase of the obtained copper composite material agglomerates more seriously and cannot be evenly distributed with the copper matrix. , enhance phase agglomeration or lead to stress concentration in the agglomerated area, which makes cracks easily generated in this area, thus affecting the performance of the material.

Figures 4 to 8 correspond to the metallographic structures of the in-situ synthesized TiB ₂ -TiC multiphase ceramics reinforced copper matrix composites obtained in Examples 1 to 5 in turn. In the presence of phase, the reinforcing phase in the obtained product can be evenly distributed in the copper matrix in the form of smaller particles, which is helpful to improve the mechanical strength of in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composites and hardness properties.

Fig. 10 is the life test result of the spot welding electrode processed by using the materials of comparative examples 1 to 3 and the materials of examples 1 to 5 under the same welding parameters. The life test result finds that the spot welding electrode prepared by using the copper matrix composite material of the present invention has Long service life.

Table 1 comparative example and embodiment material performance contrast

Copper Matrix Composite Hardness (HV _50g ) Conductivity (%IACS) Electrode life (welding times) Comparative example 1 35 98.2 200 Comparative example 2 187 78.5 1050 Comparative example 3 191 78.7 1100 Example 1 258 87.2 1650 Example 2 262 87.4 2150 Example 3 273 89.9 2850 Example 4 286 83.8 1350 Example 5 293 82.7 1450

According to the data recorded in Table 1, it can be seen that the hardness properties of the copper composites prepared in Comparative Examples 2 and 3 are improved, but the electrical conductivity is significantly reduced, while the in-situ synthesized TiB ₂ -TiC composite ceramics prepared by the present application are reinforced. The electrical conductivity of the copper-based composite material is close to that of the copper material, and the hardness is much higher than that of the copper material; and the hardness and electrical conductivity are better than those of Comparative Examples 1 and 2, which is very suitable as a spot welding electrode material.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. a preparation method of in-situ synthesis TiB ₂ -TiC multiphase ceramics reinforced copper matrix composite material, comprising the following steps: 1) Ball mill titanium element and boron carbide to obtain TiB ₂ -TiC composite ceramic precursor; 2) performing electroless nickel plating on the surface of the TiB ₂ -TiC composite ceramic precursor to obtain nickel wetting enhancement particles; 3) mixing and ball milling the nickel wetting enhancing particles and the copper source to obtain a ball mill mixture; 4) cold pressing the ball-milled mixture to obtain a compact; 5) Sintering the compact in an oxygen-free atmosphere to obtain a sintered body; 6) Forging the sintered body to obtain an in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material. 2. preparation method as claimed in claim 1, is characterized in that, the mol ratio of described titanium element and boron carbide is 3:1. 3. The preparation method according to claim 1, characterized in that, in the step 1), the speed of ball milling is 300-500r/min, and the time of ball milling is 12-24h. 4. preparation method as claimed in claim 1 is characterized in that, the temperature of the nickel plating solution that electroless nickel plating is used in described step 2) is 45～50 ℃, and the pH value of described nickel plating solution is 9～11 . 5. The preparation method according to claim 1, characterized in that, in the step 3), the mass ratio of nickel wetting enhancing particles to copper source is 0.5-5:95-99. 6. The preparation method according to claim 1, characterized in that, the pressure of the step 4) cold pressing is 300-500 MPa, and the time of cold pressing is 1-3 minutes. 7. The preparation method according to claim 1, characterized in that, the sintering temperature in the step 5) is 900-1050° C., and the sintering time is 10-30 minutes. 8. The preparation method according to claim 1, characterized in that the temperature of forging in the step 6) is 500-550°C. 9. The in-situ synthesized TiB ₂ -TiC multiphase ceramic reinforced copper matrix composite material prepared by the method according to any one of claims 1 to 8, comprising TiB ₂ -TiC multiphase ceramic reinforcement phase, copper matrix phase and coating on The nickel wetting phase on the surface of the TiB ₂ -TiC composite phase ceramic reinforcement phase, and the TiB ₂ -TiC composite phase ceramic reinforcement phase coated with the nickel wetting phase are dispersed inside and on the surface of the copper matrix phase. 10. the in-situ synthesis TiB described in claim 9 ₂ -TiC multiphase ceramic reinforced copper matrix composite material is used as the application of spot welding electrode material, described TiB ₂ -ZrB ₂ multiphase ceramic reinforced copper matrix composite material is machined successively Processing and cold extrusion to obtain spot welding electrodes.