CN102836998A - Preparation method for spot-welding electrode with high abrasion resistance, high strength and high conductivity - Google Patents

Abstract

A method for preparing a high-wear-resistant, high-strength, and high-conductivity spot welding electrode, using a low-solid-solution Cu-Al alloy with an aluminum content of no more than 0.50wt%, TiC powder with a particle size of 20-60mm, and a content of 12.14wt% of the total mass %~26.56wt%, the oxidant accounts for 2.5%~5% of the Cu-Al powder by mass percentage; the balance is Cu; its preparation process includes: mixing of oxidant, TiC powder and Cu-Al alloy powder; internal oxidation; cold ( hot) extrusion (rolling) deformation; wherein the oxidant is industrial Cu ₂ O, the sintering internal oxidation is carried out simultaneously, the sintering temperature is 900~1000°C, and the internal oxidation time is 2~6h; the dispersed copper spot welding electrode prepared by the process of the present invention Not only has high wear resistance, high strength, high conductivity, high resistance to softening temperature, but also has the advantages of short internal oxidation time, low cost and high efficiency.

Description

A kind of preparation method of spot welding electrode with high wear resistance, high strength and high conductivity

technical field

The invention relates to the scientific and technical field of metal matrix composite materials, in particular to a preparation method of a spot welding electrode with high wear resistance, high strength and high conductivity.

Background technique

High-wear-resistant, high-strength, and high-conductivity copper-based composite materials are a new type of functional material with excellent comprehensive properties. They not only have excellent wear resistance and electrical conductivity, but also have high strength and superior high-temperature performance. With the development of the electronics industry, especially after the American SCM company developed the Glidcop series Al ₂ O ₃ dispersion strengthened Cu composite materials in the late 1970s, the development and research of high-strength and high-conductivity copper-based composite materials in the United States, Japan and other developed countries is abnormal. Active, and has entered the practical stage. However, the research on this kind of material started relatively late in our country. The research on this kind of material was carried out in the late 1980s and early 1990s, but it has not yet entered the stage of practical application. It is often difficult to balance the wear resistance, electrical conductivity, strength and high temperature performance of pure copper and copper alloy materials of existing grades, and cannot fully meet the comprehensive performance requirements of the rapid development of aviation, aerospace, microelectronics and other high-tech, such as microelectronics Requirements for device spot welding electrode materials: hardness greater than or equal to 110 HBS, electrical conductivity greater than or equal to 85% IACS, high temperature resistance and softening temperature greater than or equal to 923 K.

Dispersed copper is an excellent electronic structural functional material with high wear resistance, high conductivity, high strength, and high resistance to softening temperature. It is widely used in high-power electric vacuum tubes, microelectronic device pins, integrated circuit lead frames, microwave communications, electric power Transportation and other fields are widely used in the defense industry and electronic information industry.

The traditional manufacturing technology of dispersed copper mostly adopts powder metallurgy method, among which powder internal oxidation powder metallurgy method is the most widely used, and its common technical process is: alloy smelting → powder making → internal oxidation → reduction → pressing → sintering → thermal processing → cold processing. Due to the complex process of this manufacturing technology, it is difficult to control the quality of materials and the cost is very high, which greatly limits its popularization and application. Most of the dispersed copper in the Chinese market is the product of American and Japanese companies, and the domestic scale is very small, which is difficult to meet the needs of national defense and social development.

Contents of the invention

In order to solve the above-mentioned shortcomings of poor wear resistance, low strength, poor conductivity, difficult material quality control and high cost, the present invention provides a method for preparing a high-wear-resistant, high-strength, and high-conductivity spot welding electrode. The dispersed copper spot prepared by the process method The welding electrode not only has high wear resistance, high strength, high conductivity, and high resistance to softening temperature, but also has the advantages of short internal oxidation time, low cost, and high efficiency.

In order to solve the deficiencies of the above-mentioned technical problems, the technical solution adopted by the present invention is: a preparation method of a high-wear-resistant, high-strength, high-conductivity spot welding electrode, which is characterized in that the preparation process comprises the following steps:

(1) Weigh industrial-grade Cu ₂ O with a particle size of -200 mesh, low solid-solubility Cu-Al alloy with a particle size of -200 mesh, and TiC powder with a particle size of 20-60 μm. Among them, Cu ₂ O is used as an oxidant. 2.5%~5% of the Cu-Al alloy mass, the amount of TiC powder is 12.14%~26.56% of the total mass of the oxidant, Cu-Al alloy and TiC powder, the aluminum content in the Cu-Al alloy is not More than 0.50wt%, the oxidant, Cu-Al alloy and TiC powder are mixed and placed in a ball mill for ball milling, the adopted speed is 30rpm, and the ball milling time is 12~16h;

(2) Put the ball-milled mixed powder into a graphite mold, pre-press for 5 minutes under the condition of 30MPa, and take it out for later use;

(3) Put the mixed powder in step (2) and the pre-pressed mold as a whole in a vacuum hot ^- press sintering furnace. Hot pressing and sintering for 1 to 2 hours under the condition of a pressure of 20 to 40 MPa, and then removing the pressure and sintering for 1 to 4 hours. The sintering and internal oxidation are carried out simultaneously to obtain fully internally oxidized dispersed copper, which is ready for use;

(4) Process the dispersed copper produced in step (3) to the required size to obtain the product.

In the present invention, in step (4), the processing operation is cold extrusion, hot extrusion or rolling deformation.

In the present invention, the extrusion deformation adopts one-time extrusion forming, and the rolling adopts multi-pass rolling forming.

In the present invention, in step (3), the vacuum hot pressing sintering furnace is a VDBF-250 vacuum hot pressing sintering furnace.

Spot welding electrode materials mainly include Cu, Al, Ti, C and O elements, among which Al and O exist in the form of the second phase of alumina.

Beneficial effects of the present invention:

1. The present invention uses low solid-solubility Cu-Al alloy material, which not only has high strength, similar electrical conductivity to pure copper, but also has good arc erosion resistance, electrical wear resistance and higher normal temperature strength and high temperature strength. Adding TiC powder to the Cu-Al alloy material can not only significantly improve the strength and electrical conductivity of the material, but also improve the strength, wear resistance and high temperature resistance of copper, and hot and cold extrusion or rolling deformation of dispersed copper, While meeting the size requirements, the strength of dispersed copper can be further improved by cold deformation, and this deformation strengthening effect can be retained to a higher temperature due to the dispersed distribution of nano-alumina particles and particulate titanium carbide. The present invention uses a vacuum hot-pressed sintering furnace to simultaneously carry out the sintering internal oxidation, and the oxygen source is provided by cuprous oxide under vacuum conditions, so that the internal oxidation time is obviously shortened;

2. In order to solve the following disadvantages caused by direct pressurization of materials at high temperatures: (1) Increase the compression stroke of the punch and increase the pressure on the side wall of the die. Since the melting point of copper is 1083°C, the particles are affected by the pressure at high temperatures. Thermal expansion will increase the particle stack axially and radially; (2) increase the friction between the molds, so that the pressure cannot fully act on the particles; (3) increase the void ratio between particles, which is not conducive to material densification; (4) Influence the internal oxidation reaction, the expansion of the particles at high temperature will increase the center distance between the particles, and the distance of the cuprous oxide in the particles to release the oxygen source and combine with aluminum will increase, which will affect the overall performance of the material. The present invention adopts pre-compression Operation, the preloading of the present invention adopts vacuum preloading. Under the condition of room temperature and vacuum, since the particles are in a vacuum and an unheated environment, the lubricating fluidity between the particles is good, and the particles can be close to the most closely packed, and the particles between the particles The space is closer, effectively reducing the void ratio between particles, and can more effectively improve the density of the material;

3. At present, the conductivity of domestic dispersed copper-Mo (30%) is 48.6%IACS, the microhardness is 146HV, and the density is 96.90%. The density is 95.52%, the conductivity of domestic dispersed copper-W (50%) is 46%IACS, the microhardness is 135HV, and the density is 95.52%. The softening temperature is 500°C, and the total service life (solder spot) of spot welding electrodes made of 0.6Al2O3/Cu is 50,000-55,000 times;

The dispersed copper-TiC (30%) prepared by this method has a conductivity of 82.6%IACS, a microhardness of 175 HV, a density of 99.15%, and a thermal conductivity of 90.14W×m ^-1 ×K ^-1 , which is about three times that of pure copper. The service life (solder spot) of the spot welding electrode prepared by the present invention is 68,000-72,000 times, and the softening temperature is higher than 650°C;

Experiments have shown that compared with the prior art, the dispersed copper spot welding electrode prepared by the process of the present invention not only has high wear resistance, high strength, high conductivity, and high softening temperature resistance, but also has short internal oxidation time, low cost, and high efficiency. high merit.

Detailed ways

A preparation method of a high wear-resistant, high-strength, high-conductivity spot welding electrode, the preparation method comprising the following steps:

(1) Weigh industrial-grade Cu ₂ O with a particle size of -200 mesh, low solid-solubility Cu-Al alloy with a particle size of -200 mesh, and TiC powder with a particle size of 20-60 μm. Among them, Cu ₂ O is used as an oxidant. 2.5%~5% of the Cu-Al alloy mass, the amount of TiC powder is 12.14%~26.56% of the total mass of the oxidant, Cu-Al alloy and TiC powder, the aluminum content in the Cu-Al alloy is not More than 0.50wt%, the oxidant, Cu-Al alloy and TiC powder are mixed and placed in a ball mill for ball milling, the adopted speed is 30rpm, and the ball milling time is 12~16h;

(2) Put the ball-milled mixed powder into a graphite mold, pre-press for 5 minutes under the condition of 30MPa, and take it out for later use;

(3) Put the mixed powder in step (2) and the pre-pressed mold as a whole in a vacuum hot ^- press sintering furnace. Hot pressing and sintering for 1 to 2 hours under the condition of a pressure of 20 to 40 MPa, and then removing the pressure and sintering for 1 to 4 hours. The sintering and internal oxidation are carried out simultaneously to obtain fully internally oxidized dispersed copper, which is ready for use;

(4) Process the dispersed copper produced in step (3) to the required size to obtain the product.

In step (4), the processing operation is cold extrusion, hot extrusion or rolling deformation;

The extrusion deformation adopts one-time extrusion forming, and the rolling adopts multi-pass rolling forming;

In step (3), the vacuum hot pressing sintering furnace is a VDBF-250 vacuum hot pressing sintering furnace.

The present invention will be described in detail below in conjunction with the embodiments.

Example 1

The overall spot welding electrode material in this embodiment mainly contains Cu, Al, Ti, C and O elements, wherein Al and O exist in the form of the second phase of alumina, and its content is: Al ₂ O ₃ , 0.84wt%; Ti and C exists in the form of titanium carbide reinforcement phase, its content: TiC, 12.14wt%; the balance is Cu.

The preparation process comprises the following steps:

(1) Weigh industrial-grade Cu ₂ O with a particle size of -200 mesh as the oxidant, Cu-Al alloy with a particle size of -200 mesh and TiC powder with a particle size of 20 μm, and the oxidant is 2.5% by mass of Cu-Al powder % is weighed, the TiC powder is weighed according to 12.14wt% of the total mass, and the three kinds of powders are mixed and placed in a QQM/B ball mill for ball milling. The adopted rotating speed is 30rpm, fully mixed for 14h, and mixed evenly;

(2) Put the mixed powder into the graphite mold and pre-press for 5 minutes under the condition of 30MPa;

(3) Place the powder-filled mold as a whole in a VDBF-250 vacuum hot-pressing sintering furnace at a sintering temperature of 900°C, a pressing pressure of 40 MPa, a total pressing time of 2 hours, and a vacuum degree of 1.5×10 ^-2 MPa , Under the condition that the internal oxidation time is 6h, the internal oxidation is carried out by vacuum hot-pressing sintering, and the fully internally oxidized dispersed copper is obtained;

(4) Take the dispersed copper produced in step (3) for hot extrusion deformation: cut the above dispersed copper-TiC block with a sawing machine into small sections with a diameter of 5 mm and a length of 40 mm, and heat them in a box-type resistance furnace RX3-15-9 Heat to 850 ℃ in a small box-type resistance furnace, hold for 20 minutes, and hot-extrude on a YB32-100B four-column hydraulic press to form spot welding electrodes for microelectronic devices with a diameter of 3 mm.

Example 2

The overall spot welding electrode material in this embodiment mainly contains Cu, Al, Ti, C and O elements, wherein Al and O exist in the form of the second phase of alumina, and its content is: Al ₂ O ₃ , 0.95wt%; Ti and C exists in the form of titanium carbide reinforcement phase, its content: TiC, 19.22wt%; the balance is Cu.

The preparation process comprises the following steps:

(1) Weigh industrial-grade Cu ₂ O with a particle size of -200 mesh as the oxidant, Cu-Al alloy with a particle size of -200 mesh and TiC powder with a particle size of 40 μm, and the oxidant is 3.7% by mass of Cu-Al powder % is weighed, the TiC powder is weighed according to 19.22wt% of the total mass, and the three kinds of powders are mixed and placed in a QQM/B ball mill for ball milling. The rotating speed used is 30rpm, and the mixture is fully mixed for 12h to make it evenly mixed;

(2) Put the mixed powder into the graphite mold and pre-press for 5 minutes under the condition of 30MPa;

(3) Place the powder-filled mold as a whole in a VDBF-250 vacuum hot-pressing sintering furnace at a sintering temperature of 950°C, a pressing pressure of 20MPa, a total pressing time of 1.5h, and a vacuum degree of 1.5×10 ^-2 Under the conditions of MPa and internal oxidation time of 4h, vacuum hot-pressing sintering internal oxidation is carried out to obtain completely internally oxidized dispersed copper;

(4) Cool the dispersed copper produced in step (3) to room temperature for rolling deformation: roll the dispersed copper plate produced in step (3) into a plate with a width of 50mm×thickness of 2mm with a small four-roll cold rolling mill.

Example 3

The overall spot welding electrode material in this embodiment mainly contains Cu, Al, Ti, C and O elements, wherein Al and O exist in the form of the second phase of alumina, and its content is: Al ₂ O ₃ , 0.79wt%; Ti and C exists in the form of titanium carbide reinforcement phase, its content: TiC, 26.56wt%; the balance is Cu.

The preparation process comprises the following steps:

(1) Take industrial-grade Cu ₂ O with a particle size of -200 mesh as the oxidant, Cu-Al alloy with a particle size of -200 mesh and TiC powder with a particle size of 60 μm, and the oxidant is 5% by mass of the Cu-Al powder. % is weighed, the TiC powder is weighed according to 26.56wt% of the total mass, and the three kinds of powders are mixed and then placed in a QQM/B ball mill for ball milling at a rotating speed of 30rpm, fully mixed for 16h to make it evenly mixed;

(2) Put the mixed powder into the graphite mold and pre-press for 5 minutes under the condition of 30MPa;

(3) Place the powder-filled mold as a whole in a VDBF-250 vacuum hot-pressing sintering furnace at a sintering temperature of 1000°C, a pressing pressure of 30 MPa, a total pressing time of 1 h, and a vacuum degree of 1.5×10 ^-2 MPa , Under the condition that the internal oxidation time is 2h, the internal oxidation is carried out by vacuum hot-pressing sintering, and the dispersed copper that is completely internally oxidized is obtained;

(4) Take the dispersed copper produced in step (3) for hot extrusion deformation: cut the above dispersed copper-TiC block with a sawing machine into small sections with a diameter of 5 mm and a length of 40 mm, and heat them in a box-type resistance furnace RX3-15-9 Heat to 850 ℃ in a small box-type resistance furnace, hold for 20 minutes, and hot-extrude on a YB32-100B four-column hydraulic press to form spot welding electrodes for microelectronic devices with a diameter of 3 mm.

Example 4

The overall spot welding electrode material in this embodiment mainly contains Cu, Al, Ti, C and O elements, wherein Al and O exist in the form of the second phase of alumina, and its content is: Al ₂ O ₃ , 0.84wt%; Ti and C exists in the form of titanium carbide reinforcement phase, its content: TiC, 19.22wt%; the balance is Cu.

The preparation process comprises the following steps:

(1) Weigh industrial-grade Cu ₂ O with a particle size of -200 mesh as the oxidant, Cu-Al alloy with a particle size of -200 mesh and TiC powder with a particle size of 48 μm, and the oxidant is 3.7% by mass of Cu-Al powder % is weighed, the TiC powder is weighed according to 19.22wt% of the total mass, and the three kinds of powders are mixed and placed in a QQM/B ball mill for ball milling at a speed of 30 rpm, fully mixed for 14 hours, and mixed evenly;

(2) Put the mixed powder into the graphite mold and pre-press for 5 minutes under the condition of 30MPa;

(3) Place the powder-filled mold as a whole in a VDBF-250 vacuum hot-pressing sintering furnace at a sintering temperature of 1000°C, a pressing pressure of 30 MPa, a total pressing time of 1 h, and a vacuum degree of 1.5×10 ^-2 MPa , Under the condition that the internal oxidation time is 2h, the internal oxidation is carried out by vacuum hot-pressing sintering, and the dispersed copper that is completely internally oxidized is obtained;

(4) Take the dispersed copper prepared in step (3) for hot extrusion deformation: cut the above dispersed copper-TiC block with a sawing machine into small sections with a diameter of 5 mm and a length of 40 mm, and heat them in a box-type resistance furnace RX3-15-9 Heat to 850 ℃ in a small box-type resistance furnace, hold for 20 minutes, and hot-extrude on a YB32-100B four-column hydraulic press to form spot welding electrodes for microelectronic devices with a diameter of 3 mm.

Claims (4)

1. the preparation method of a high abrasion high-strength high conductivity spot-wedling electrode is characterized in that, its preparation technology's method may further comprise the steps:

(1) takes by weighing granularity respectively and be-200 purpose technical grade Cu ₂O, granularity are that low solid solubility Cu-Al alloy of-200 purposes and granularity are the TiC powder of 20 ~ 60 μ m, wherein, and Cu ₂O is as oxidant; Its consumption is 2.5% ~ 5% of a Cu-Al alloy mass; The consumption of TiC powder is 12.14% ~ 26.56% of oxidant, Cu-Al alloy and a TiC powder three gross mass, and the aluminium content in the described Cu-Al alloy is not more than 0.50wt%, oxidant, Cu-Al alloy and TiC powder mixes is placed on carries out ball milling in the ball mill; The rotating speed that adopts is 30rpm, and the ball milling time is 12 ~ 16h;

(2) in mixed-powder that ball milling is good was packed graphite jig into, precompressed 5min under the condition of 30MPa took out subsequent use;

(3) with in the step (2) mixed-powder being housed, and placing the vacuum heating-press sintering stove through the mold integral of precompressed, is that 900 ~ 1000 ℃, vacuum are 1.5 * 10 in sintering temperature ^-2MPa, compacting pressure are hot pressed sintering 1 ~ 2h under the condition of 20 ~ 40MPa, remove pressure sintering 1 ~ 4h then, and described sintering and interior oxidation are carried out synchronously, obtain the disperse copper of fully interior oxidation, and be subsequent use;

(4) getting disperse copper that step (3) produces is processed as needed size and promptly obtains product.

2. the preparation method of a kind of high abrasion high-strength high conductivity spot-wedling electrode according to claim 1 is characterized in that: in the step (4), described process operation is cold extrusion, hot extrusion or rolling deformation.

3. the preparation method of a kind of high abrasion high-strength high conductivity spot-wedling electrode according to claim 2 is characterized in that: an extrusion molding, the roll forming of described rolling employing multi-pass are adopted in described crimp.

4. the preparation method of a kind of high abrasion high-strength high conductivity spot-wedling electrode according to claim 1 is characterized in that: in the step (3), described vacuum heating-press sintering stove is a VDBF-250 vacuum heating-press sintering stove.