CN107686904A - A kind of lanthanum hexaboride dispersion-strengthened Cu base contact material and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of lanthanum hexaboride dispersion-strengthened Cu base contact material and preparation method thereof, it is by Cu, Cr and LaB₆Powder is according to mass percent Cu 64.4%~68.6%, Cr 27.6%~29.4%, LaB₆After 2%~8% is well mixed, then 10~100mm of diameter for being formed through discharge plasma sintering, draw ratio 0.1~2.0, consistency are more than 98.0%, low gas content amount, electric-conductivity heat-conductivity high, the LaB of even tissue₆Dispersion-strengtherning CuCr alloy cylinder ingots.LaB prepared by the present invention₆Dispersion-strengtherning CuCr contact materials have good dieletric strength and resistance to arc erosion energy, have a extensive future.

Description

A kind of lanthanum hexaboride dispersion-strengthened Cu base contact material and preparation method thereof

Technical field

The invention belongs to PM technique, and in particular to a kind of LaB₆Dispersion-strengthened Cu base contact material and its preparation side Method.

Background technology

CuCr alloys are widely used in middle pressure vacuum and broken because having good arc resistant corrosive power and breaking current ability In the device of road.The performance of CuCr alloys depends primarily on the compactness and uniformity of its institutional framework.Powder metallurgic method is system The most frequently used method of standby CuCr alloys.But because the mutual solubility between Cu and Cr is very low, wellability is poor, therefore closed in CuCr All it is to first pass through sintering and prepare to have effigurate porous C r skeletons in the significant period of time of gold research and development, then infiltration Cu and obtain CuCr alloy products；Cold or hot re-pressing is carried out to the CuCr alloys after infiltration again if necessary, reaches product and meets It is required that density and intensity.Therefore, limited by preparation technology, a certain amount of defect always be present in product, influence material performance and Service life.

Discharge plasma sintering (SPS) be using flash DC current flow through powder or mould produce Joule heat and to powder End carries out a kind of new technology of rapidly solidified shaping.In the recent period, Chinese patent 106086493A discloses a kind of fast low temperature sintering The method for preparing CuCr alloy materials, this method are to carry out Low Temperature Solid-Phase sintering to CuCr mixed-powders using SPS.Then, Chinese patent CN106498205A discloses a kind of manufacture method of the CuCr alloys of large scale high-compactness high uniformity, passes through Rationally design mould and pressure head structure, the improvement suitable sintering parameter of CURRENT DISTRIBUTION simultaneous selection produce large scale high-compactness The CuCr alloys of high uniformity.Compared with prior powder metallurgy method, the tissue of the CuCr alloys prepared using SPS technologies is thin It is small, hardness increase.The proof voltage ability of CuCr alloys is directly proportional to the hardness of alloy.Can further it be carried by adding ceramic particle The hardness of CuCr alloys is risen, and then significantly improves its proof voltage ability.LaB₆With good heat endurance and chemically stable Property, that evaporation rate is low, work function is low, emission is big under high-melting-point, high temperature and anti-Ions Bombardment sputtering ability is strong etc. is excellent Point.LaB is added into CuCr alloys₆Be expected in high pressure vacuum breakdown process, improve arc motion characteristic, make electric arc prior to LaB₆Mutually produce, realize active striking, repeatedly burning and extinguishing of the high-temperature electric arc in copper phase are avoided, so as to improve CuCr contacts The resistance to arc erosion energy of material, extends its service life, improves the reliability and stability of electrical system.

The content of the invention

It is an object of the invention to for existing mesohigh vacuum copper-base contact material, especially high-compactness, into packet Uniform and CuCr alloy materials of high rigidity and preparation method thereof weak point is knitted, by CuCr alloying components formula and burning Tie the optimum choice of technique, there is provided a kind of LaB₆Copper-base contact material of dispersion-strengtherning and preparation method thereof, improve copper-based contact The hardness of material, improve its dieletric strength and resistance to arc erosion energy, to lift the quality of China's vacuum contact material.

The present invention adopts the following technical scheme that to realize goal of the invention：

The lanthanum hexaboride dispersion-strengthened Cu base contact material of the present invention, containing copper and chromium, its feature is：Also contain LaB₆, it is by Cu, Cr and LaB₆Powder is according to mass percent Cu 64.4%~68.6%, Cr 27.6%~29.4%, LaB₆ After 2%~8% is well mixed, then form through discharge plasma sintering.Preferably, as Cu, Cr and LaB₆The quality percentage of powder Than for Cu 67.2%, Cr 28.8%, LaB₆When 4%, resulting materials combination property is optimal.

The preparation method of lanthanum hexaboride dispersion-strengthened Cu base contact material of the present invention, comprises the following steps：

Step 1, claim powder

Weigh raw material Cu powder, Cr powder and LaB respectively according to mass percent₆Powder；

Step 2, mixed powder

Cu powder, Cr powder and the LaB that step 1 is weighed₆Powder is placed in V-type batch mixer, and mixing is no less than 10 hours, is obtained Obtain mixed-powder；

Step 3, discharge plasma sintering

The mixed-powder that step 2 is obtained is weighed, is fitted into graphite jig, using hand-operated hydraulic press to the graphite that fills Mould carries out precompressed, and pressure is 8~12MPa；

Then the carbon felt thick with 4 contour~6mm of graphite jig is wrapped in graphite jig periphery, then is placed on electric discharge etc. In the furnace chamber of ion sintering system, below 5Pa is evacuated to, shaping is sintered to powder, sintering process is：

Axial mechanical pressure：10~50MPa,

Heating rate：20~100 DEG C/min,

Sintering temperature：850~950 DEG C,

Soaking time：3~15min；

After furnace cooling, that is, obtain the LaB of high-compactness, low gas content amount and even tissue₆Dispersion-strengtherning CuCr alloys are justified Post ingot.

Preferably：The oxygen content of the Cu powder is not more than 200 mesh less than 500ppm, particle diameter；The oxygen content of the Cr powder is low In 800ppm, particle diameter between the mesh of 80 mesh~240；The LaB₆Oxygen content in power is 10~20 μm less than 500ppm, particle diameter.Institute The LaB of preparation₆Dispersion-strengtherning CuCr alloy cylinder ingots variable dimensions, a diameter of 10~100mm, draw ratio 0.1~2.0.

Preferably：

As prepared LaB₆During the diameter ＜ 40mm of dispersion-strengtherning CuCr alloy cylinder ingots, the sintering process is：

Axial mechanical pressure：30~50MPa,

Heating rate：50~100 DEG C/min,

Sintering temperature：900~950 DEG C,

Soaking time：10~15min；

As diameter >=40mm of prepared CuCr alloy cylinder ingots, the sintering process is：

Heating rate：20~30 DEG C/min,

Sintering temperature：850~900 DEG C,

Soaking time：3~10min,

Axial mechanical pressure：Using step pressuring method, when temperature≤500 DEG C, axial compressive force 10MPa；Work as temperature> At 500 DEG C, axial compressive force 30MPa.

Beneficial effects of the present invention are embodied in：

1st, by Cu, Cr and LaB₆Weight/mass percentage composition optimization, LaB of the invention₆Dispersion strengthening copper-based contact material Material formula is reasonable, both using the LaB of Dispersed precipitate₆The hardness of material is improved, and then improves the proof voltage of CuCr contact materials Intensity, electric arc can be made again prior to LaB₆Mutually produce, improve arc motion characteristic, improve the resistance to arc erosion of CuCr contact materials Performance, extend its service life.In addition, pass through the LaB prepared to embodiment₆The survey of dispersion-strengtherning CuCr alloy combination properties Examination, it was confirmed that the combination property of CuCr contact materials can be effectively improved using optimization of C/C composites of the present invention.

2nd, the present invention using discharge plasma sintering technique realizes high-compactness, structural constituent uniformly and high rigidity The consolidation of CuCr contact materials, technique is simple, the cycle is short, production efficiency is high；The LaB of gained₆Dispersion-strengtherning CuCr alloys Through follow-up a small amount of processing can finished product and as the parts of vacuum circuit breaker in high-power power transmission and transforming equipment, can significantly be lifted The quality of domestic vacuum contact material.

3rd, present invention optimizes LaB₆The preparation technology of dispersion-strengtherning CuCr contact materials, to different-diameter and draw ratio CuCr alloys cylinder ingots use different process conditions, and its performance can be made further to improve.

4th, LaB prepared by the present invention₆There is dispersion-strengtherning CuCr contact materials good dieletric strength and resistance to electric arc to invade Corrosion energy, has a extensive future.

Brief description of the drawings

Fig. 1 is the gained LaB of the embodiment of the present invention 2₆The microstructure photo of dispersion-strengtherning CuCr contact materials.

Embodiment

By following examples, the present invention will be further described, but embodiments of the present invention are not limited only to this.

It is not more than the Ni metal powder of 200 mesh less than 500ppm, particle diameter from oxygen content in following examples, from oxygen content Less than the metal Cr powder of 800ppm, particle diameter between the mesh of -80 mesh~+240, from oxygen content less than 500ppm, particle diameter be 10~ 20 μm of LaB₆Powder.

Discharge plasma sintering stove used in following embodiments is the LABOX systems of Japanese Sinter Land Inc companies production Row discharge plasma sintering system, its current type are DC pulse current, pulse train 40:7.

Embodiment 1

The present embodiment LaB₆The preparation method of dispersion-strengtherning CuCr contact materials is to carry out as follows：

Step 1：Claim powder

According to mass percent Cu 67.2%, Cr 28.8%, LaB₆4%, raw material Cu powder, Cr powder and LaB are weighed respectively₆ Powder；

Step 2, mixed powder

Cu powder, Cr powder and the LaB that step 1 is weighed₆Powder is placed in V-type batch mixer, is mixed 10 hours, is mixed Powder；

Step 3, discharge plasma sintering

The mixed-powder that 25.3g steps 2 are obtained is weighed, is fitted into graphite jig, using hand-operated hydraulic press to filling Mould carry out precompressed, pressure is~10MPa；

Then wrapped in graphite jig periphery with graphite jig it is contour~thick 5mm carbon felt, then be placed on electric discharge etc. In the furnace chamber of ion sintering system, below 5Pa is evacuated to, shaping is sintered to powder, sintering process is：

Axial mechanical pressure：50MPa；

Heating rate：100℃/min；

Sintering temperature：950℃；

Soaking time：15min；

The LaB of Φ 20mm × 10mm high-compactness, low gas content amount and even tissue is can obtain after furnace cooling₆Disperse Strengthen CuCr alloy cylinder ingots, its bulk density is 8.01g/cm³(consistency 99.5%), oxygen content 380ppm, hardness For 130HV, electrical conductivity 27.1Ms/m.

Embodiment 2

The present embodiment LaB₆The preparation method of dispersion-strengtherning CuCr contact materials is to carry out as follows：

Step 1：Claim powder

According to mass percent Cu 67.2%, Cr 28.8%, LaB₆4%, raw material Cu powder, Cr powder and LaB are weighed respectively₆ Powder；

Step 2, mixed powder

Cu powder, Cr powder and the LaB that step 1 is weighed₆Powder is placed in V-type batch mixer, is mixed 10 hours, is mixed Powder；

Step 3, discharge plasma sintering

The mixed-powder that 2170.0g steps 2 are obtained is weighed, is fitted into graphite jig, using hand-operated hydraulic press to filling Good mould carries out precompressed, and pressure is~10MPa；

Then wrapped in graphite jig periphery with graphite jig it is contour~thick 5mm carbon felt, then be placed on electric discharge etc. In the furnace chamber of ion sintering system, below 5Pa is evacuated to, shaping is sintered to powder, sintering process is：

Axial mechanical pressure：(room temperature is to 500 DEG C by 10~30MPa：10MPa；Higher than 500 DEG C：30MPa)；

Heating rate：30℃/min；

Sintering temperature：850℃；

Soaking time：3min；

The LaB of Φ 70mm × 70mm high-compactness, low gas content amount and even tissue is can obtain after furnace cooling₆Disperse Strengthen CuCr alloy cylinder ingots, its bulk density is 7.92g/cm³(consistency 98.3%), oxygen content 420ppm, hardness For 134HV, electrical conductivity 26.9Ms/m.

Embodiment 3

The present embodiment LaB₆The preparation method of dispersion-strengtherning CuCr contact materials is to carry out as follows：

Step 1：Claim powder

According to mass percent Cu 64.4%, Cr 27.6%, LaB₆8%, raw material Cu powder, Cr powder and LaB are weighed respectively₆ Powder；

Step 2, mixed powder

Cu powder, Cr powder and the LaB that step 1 is weighed₆Powder is placed in V-type batch mixer, is mixed 10 hours, is mixed Powder；

Step 3, discharge plasma sintering

The mixed-powder that 55.5g steps 2 are obtained is weighed, is fitted into graphite jig, using hand-operated hydraulic press to filling Mould carry out precompressed, pressure is~10MPa；

Then wrapped in graphite jig periphery with graphite jig it is contour~thick 5mm carbon felt, then be placed on electric discharge etc. In the furnace chamber of ion sintering system, below 5Pa is evacuated to, shaping is sintered to powder, sintering process is：

Axial mechanical pressure：40MPa；

Heating rate：100℃/min；

Sintering temperature：900℃；

Soaking time：10min；

The LaB of Φ 30mm × 10mm high-compactness, low gas content amount and even tissue is can obtain after furnace cooling₆Disperse Strengthen CuCr alloy cylinder ingots, its bulk density is 7.80g/cm³(consistency 99.8%), oxygen content 350ppm, hardness For 149HV, electrical conductivity 24.0Ms/m.

Embodiment 4

The present embodiment LaB₆The preparation method of dispersion-strengtherning CuCr contact materials is to carry out as follows：

Step 1：Claim powder

According to mass percent Cu 68.6%, Cr 29.4%, LaB₆2%, raw material Cu powder, Cr powder and LaB are weighed respectively₆ Powder；

Step 2, mixed powder

Cu powder, Cr powder and the LaB that step 1 is weighed₆Powder is placed in V-type batch mixer, is mixed 10 hours, is mixed Powder；

Step 3, discharge plasma sintering

The mixed-powder that 1125.0g steps 2 are obtained is weighed, is fitted into graphite jig, using hand-operated hydraulic press to filling Good mould carries out precompressed, and pressure is~10MPa；

Then wrapped in graphite jig periphery with graphite jig it is contour~thick 5mm carbon felt, then be placed on electric discharge etc. In the furnace chamber of ion sintering system, below 5Pa is evacuated to, shaping is sintered to powder, sintering process is：

Axial mechanical pressure：(room temperature is to 500 DEG C by 10~30MPa：10MPa；Higher than 500 DEG C：30MPa)；

Heating rate：30℃/min；

Sintering temperature：860℃；

Soaking time：5min；

The LaB of Φ 50mm × 70mm high-compactness, low gas content amount and even tissue is can obtain after furnace cooling₆Disperse Strengthen CuCr alloy cylinder ingots, its bulk density is 8.08g/cm³(consistency 98.9%), oxygen content 400ppm, hardness For 108HV, electrical conductivity 25.8Ms/m.

It the foregoing is only the citing of embodiments of the present invention, it is noted that for the ordinary skill of the art For personnel, without departing from the technical principles of the invention, some improvement and deformation can also be made, these improve and become Shape is also considered as protection scope of the present invention.

Claims (6)

1. a kind of lanthanum hexaboride dispersion-strengthened Cu base contact material, contains copper and chromium, it is characterised in that：Also contain LaB₆, be by Cu, Cr and LaB₆Powder is according to mass percent Cu 64.4%~68.6%, Cr 27.6%~29.4%, LaB₆2%~8% After well mixed, then form through discharge plasma sintering.

2. lanthanum hexaboride dispersion-strengthened Cu base contact material according to claim 1, it is characterised in that：Cu, Cr and LaB₆Powder The mass percent at end is respectively Cu 67.2%, Cr 28.8%, LaB₆4%.

3. a kind of preparation method of the lanthanum hexaboride dispersion-strengthened Cu base contact material described in claim 1 or 2, its feature exist In comprising the following steps：

Step 1, claim powder

Weigh raw material Cu powder, Cr powder and LaB respectively according to mass percent₆Powder；

Step 2, mixed powder

Cu powder, Cr powder and the LaB that step 1 is weighed₆Powder is placed in V-type batch mixer, and mixing is no less than 10 hours, is mixed Close powder；

Step 3, discharge plasma sintering

The mixed-powder that step 2 is obtained is weighed, is fitted into graphite jig, using hand-operated hydraulic press to the graphite jig that fills Precompressed is carried out, pressure is 8~12MPa；

Then the carbon felt thick with 4 contour~6mm of graphite jig is wrapped in graphite jig periphery, then is placed on plasma discharging In the furnace chamber of sintering system, below 5Pa is evacuated to, shaping is sintered to powder, sintering process is：

Axial mechanical pressure：10~50MPa,

Heating rate：20~100 DEG C/min,

Sintering temperature：850~950 DEG C,

Soaking time：3~15min；

After furnace cooling, that is, obtain the LaB of high-compactness, low gas content amount and even tissue₆Dispersion-strengtherning CuCr alloy cylinder ingots.

4. preparation method according to claim 3, it is characterised in that：The oxygen content of the Cu powder is less than 500ppm, particle diameter No more than 200 mesh；The oxygen content of the Cr powder is less than 800ppm, particle diameter between the mesh of 80 mesh~240；The LaB₆Powder oxygen contains Amount is 10~20 μm less than 500ppm, particle diameter.

5. preparation method according to claim 3, it is characterised in that：Prepared LaB₆Dispersion-strengtherning CuCr alloy cylinders Ingot variable dimension, a diameter of 10~100mm, draw ratio 0.1~2.0.

6. the preparation method according to claim 3 or 5, it is characterised in that：

As prepared LaB₆During the diameter ＜ 40mm of dispersion-strengtherning CuCr alloy cylinder ingots, the sintering process is：

Axial mechanical pressure：30~50MPa,

Heating rate：50~100 DEG C/min,

Sintering temperature：900~950 DEG C,

Soaking time：10~15min；

As diameter >=40mm of prepared CuCr alloy cylinder ingots, the sintering process is：

Heating rate：20~30 DEG C/min,

Sintering temperature：850~900 DEG C,

Soaking time：3~10min,

Axial mechanical pressure：Using step pressuring method, when temperature≤500 DEG C, axial compressive force 10MPa；Work as temperature>500 DEG C when, axial compressive force 30MPa.