CN110102771A - A kind of preparation method of high green compact high stability environmental protection diffusion type tin zinc-copper powder - Google Patents

Abstract

The invention discloses a kind of preparation method of high green compact high stability environmental protection diffusion type tin zinc-copper powder, a kind of preparation method of high green compact high stability environmental protection diffusion type tin zinc-copper powder is the following steps are included: (1) raw material is chosen: it is spare to choose the secondary resources such as high-purity copper, zinc and the copper-tin alloy leftover pieces of certain mass number；(2) low pine is than the formation of prealloy powder: high-purity copper powder of low apparent density and Albaloy powder is prepared by using water atomization, by the parameter for adjusting atomization process.Pass through the innovation to production technology, formula technique, equipment development etc. in the present invention, Gu admittedly diffusion type tin zinc-copper powder technology of preparing, its product stability is high, compared with conventional diffusion technique (copper powder, glass putty, zinc powder mixing diffusion), uniformity is good, basic segregation-free, production cost is low (glass putty, zinc powder are at high price), meanwhile the present invention substantially increases product production capacity and production efficiency, considerably reduces equipment investment and energy consumption.

Description

A kind of preparation method of high green body high stability environment-friendly diffusion tin-zinc-copper powder

technical field

The invention relates to the technical field of metal materials, in particular to a preparation method of high-green body, high-stability and environment-friendly diffusion-type tin-zinc-copper powder.

Background technique

Thermal diffusion tin-zinc-copper powder (CuSn6Zn6) is a lead-free copper alloy powder developed in recent years. It has excellent formability, high green strength, and stable sintered size change. It has broad market prospects and is popular among domestic and foreign copper powder manufacturers. Take it as a key research object, such as Fukuda Metal Foil Powder Industry Co., Ltd. of Japan, ACuPowder International of the United States, and China Youyan Powder New Material Co., Ltd., etc., but the existing products have high bulk density, poor composition uniformity and stability, and are seriously Restricting product performance, for this reason, we propose a preparation method of high green body, high stability and environmental protection diffusion tin-zinc-copper powder.

Contents of the invention

The purpose of the present invention is to provide a method for preparing high-green body, high-stability and environment-friendly diffusion tin-zinc-copper powder, so as to solve the problems raised in the background technology.

In order to achieve the above object, the present invention provides the following technical solution: a method for preparing a high-green body high-stability environment-friendly diffusion tin-zinc-copper powder, the preparation method of the high-green body high-stability environment-friendly diffusion type tin-zinc-copper powder includes The following steps:

(1) Raw material selection: Select secondary resources such as high-purity copper, zinc and copper-tin alloy scraps in a certain number of parts for standby;

(2) Formation of low-porosity pre-alloyed powder: High-purity low-porosity copper powder and copper-tin-zinc alloy powder are prepared by water atomization, and the particle shape is irregular by adjusting the parameters of the atomization process, and the particle size is improved. Hollowness, the resulting pre-alloyed powder has a regular porous shape and a loose specific density lower than 2.0g/cm³;

(3) Achieving high green strength: through the "solid-solid" two-phase thermal diffusion process, adding an appropriate amount of special lubricants to improve the green performance of the product, through the phase transition mechanism and interface reaction process in the thermal diffusion process Carry out research, for the integration optimization and demonstration of tin-zinc-copper powder technology, the green body forming pressure of the alloy powder treated with special lubricant can reach more than 12MPa;

(4) Reduce the degree of segregation and improve performance: reduce the segregation performance by changing the two key factors of intragranular segregation performance and specific gravity segregation performance during the powder forming process. The main method is to use the principle of kinetic + thermodynamic mechanism to change the diffusion of grain atoms To reduce the degree of intragranular segregation; adopt the reverse sequential solidification method to change the solidification sequence of the mother liquor and the proportioning liquor to reduce the specific gravity segregation of the material.

Preferably, the tin-zinc-copper powder produced by solid-solid diffusion technology in the high-green body, high-stability, and environment-friendly diffusion tin-zinc-copper powder with low bulk ratio pre-alloyed powder uses CuSnZn alloy powder+CuSn alloy powder+ Combination form of Cu powder is the basic material. By adjusting the parameters of the atomization process, the shape of the particles is irregular, the hollowness of the particles is improved, and the resulting shape is regular and porous. The bulk specific density of the multi-hollowness is lower than 2.0g/cm³ pre-alloyed powder;

The process control measures in the production of the low loose ratio pre-alloyed powder include the following steps:

(1) The degree of superheat of the metal melt: the greater the degree of superheat, the smaller the surface tension of the molten metal, the easier it is for the first droplet to form, and the generated particles are finer, but the time required for cooling is longer, the irregularity of the metal is reduced, and the looseness Ratio;

(2) Cooling water level: The cooling water level is low, the distance of particles flying in the air is long, and the irregularity is reduced. When the superheating degree is low and the atomization medium flow rate is large, the influence is not great, as long as the cooling water level does not affect the atomization process. possibly high;

(3) The structure of the nozzle and the related size: Under the same conditions, the structure of the nozzle is different, and the state of the atomizing medium and the metal melt is completely different when the metal is atomized, which directly affects the atomization effect. For the free fall type Nozzles generally have "V"-shaped plate type, cone, annular hole, annular seam and other structural forms. Using "V"-shaped plate type nozzles cannot form a closed atomization area during atomization, and the metal melt is wavy before atomization. Belt, after atomization, the particle size is large and the composition rate is low. The annular seam nozzle is difficult to process, the combined abrasive tool structure requires high requirements during installation, and the concentricity is too low, resulting in uneven distribution and non-focus of the atomized medium, and effective atomization cannot be carried out. Therefore, the annular hole structure is more reasonable. To achieve the process purpose, The ring hole structure must meet the following requirements: A. The hole diameter is small, the holes are evenly distributed, and the holes are fully focused, which can form a closed atomization area; B. The ring hole resistance of the nozzle is small. Under the same atomization pressure, the speed of the atomized medium at the nozzle outlet increases , high subdivision rate, sufficient atomization; C atomization top angle is reasonable, large atomization top angle, small jet distance, reduced irregularity, no obvious particle size change, high efficiency, but too large atomization top angle, easy to block nozzle;

(4) Atomization pressure: the speed of the water jet. When the atomization pressure is less than 7MPa, the greater the pressure, the smaller the particle size. When the pressure is less than 7MPa, the pressure has little effect on the particle size. However, when the degree of superheat is small, the atomization pressure has an impact on the particle size and irregularity, and the atomization pressure is high, and the particle size and irregularity increase. To increase the speed of the water jet, on the one hand, increase the atomization pressure, and on the other hand, reduce the resistance of the nozzle, by reducing the aspect ratio of the nozzle and improving the smoothness of the inner surface of the nozzle;

(5) Water flow rate: Although the energy actually used to produce dispersed powder particles is a small part of the energy consumed in the atomization process, a larger water flow rate can better reduce the humidity of the crushed powder and slow down the spheroidization. Decreasing the loose ratio has little effect on particle size.

Preferably, the method for realizing the high green strength alloy powder in the high green stability and environmental protection diffusion tin-zinc-copper powder includes the following steps:

(1) Using secondary resources such as high-purity copper, zinc and copper-tin alloy scraps as raw materials, the metal solution is obtained by melting in an induction furnace, and the metal solution is degassed and deslagged by blowing argon at the bottom of the furnace, and then left to stand Slag, so that the impurity content in the melt is less than 0.2%, the metal solution is then passed through a special nozzle, and copper powder and copper-tin-zinc alloy powder are prepared by water atomization;

(2) Water-atomized copper or copper alloy powder has a small amount of oxidation on the surface, so the oxidation-reduction process is used to modify the water-atomized copper powder and copper-tin-zinc alloy powder to further improve its performance. Oxidation-reduction process is adopted: the oxidation temperature is 300-500°C, and the oxidation time is 2-4h. According to the oxidation process, during the oxidation process, after oxidation, the reduction is carried out in hydrogen, and the reduction temperature is 400-600°C. Chemical reaction equation:

Oxidation reaction: 2M (metal) + O2 = 2MO

Reduction reaction: MO+H2=M+H2O

The oxidation-reduction process conforms to the thermodynamic theorem. According to the thermodynamic temperature map, it can be consulted. Among them, copper is oxidized first. In copper alloys, after oxidation, the volume of oxygen occupies a certain position in the particles, resulting in the growth of particles. Then after reduction, it forms a porous structure, and an appropriate amount of special lubricant is added through the "solid-solid" two-phase thermal diffusion process to improve the green performance of the product. Aiming at the influence of process parameters on powder properties in this process, the phase transformation mechanism and interface reaction process in the thermal diffusion process are studied, which is the integration optimization and demonstration of tin-zinc-copper powder technology. The alloy powder treated with special lubricant can have a green forming pressure of more than 12MPa.

Preferably, the method for reducing the segregation degree and improving the performance of the high-green body, high-stability, and environment-friendly diffusion tin-zinc-copper powder is the method of reducing the specific gravity segregation degree: changing the traditional solidification and atomization process, and adopting top-down solidification and atomization Technology, by adjusting the temperature, angle and other parameters of the atomizer, reverse solidify the combination sequence of primary crystals, first solidify tin and zinc with low melting point, and then solidify copper with high melting point, and generate crystal grains of different metal materials during fusion The fusion body, through the mechanism of thermodynamics + kinetics, realizes secondary fusion to reduce specific gravity segregation.

In the present invention, through the innovation of production technology, formula technology, equipment development and other aspects, the solid diffusion type tin-zinc-copper powder preparation technology has high product stability, which is different from the traditional diffusion process (mixed diffusion of copper powder, tin powder and zinc powder) ) compared with ) with good uniformity, basically no segregation, and low production cost (tin powder and zinc powder are expensive). At the same time, the present invention greatly improves product production capacity and production efficiency, and greatly reduces equipment investment and energy consumption.

Detailed ways

The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Embodiment one:

A method for preparing a high-green body high-stability environment-friendly diffusion tin-zinc-copper powder, the preparation method of the high-green body high-stability environment-friendly diffusion type tin-zinc-copper powder comprises the following steps:

(1) Raw material selection: Select secondary resources such as high-purity copper, zinc and copper-tin alloy scraps in a certain number of parts for standby;

(2) Formation of low-porosity pre-alloyed powder: High-purity low-porosity copper powder and copper-tin-zinc alloy powder are prepared by water atomization, and the particle shape is irregular by adjusting the parameters of the atomization process, and the particle size is improved. Hollowness, the resulting pre-alloyed powder has a regular porous shape and a loose specific density lower than 2.0g/cm³;

(3) Achieving high green strength: through the "solid-solid" two-phase thermal diffusion process, adding an appropriate amount of special lubricants to improve the green performance of the product, through the phase transition mechanism and interface reaction process in the thermal diffusion process Carry out research, for the integration optimization and demonstration of tin-zinc-copper powder technology, the green body forming pressure of the alloy powder treated with special lubricant can reach more than 12MPa;

(4) Reduce the degree of segregation and improve performance: reduce the segregation performance by changing the two key factors of intragranular segregation performance and specific gravity segregation performance during the powder forming process. The main method is to use the principle of kinetic + thermodynamic mechanism to change the diffusion of grain atoms To reduce the degree of intragranular segregation; adopt the reverse sequential solidification method to change the solidification sequence of the mother liquor and the proportioning liquor to reduce the specific gravity segregation of the material.

Embodiment two:

The high green body, high stability and environmental protection diffusion type tin-zinc-copper powder with low porosity ratio pre-alloyed powder adopts solid diffusion technology to produce the tin-zinc-copper powder. In the selection of materials, the combination of CuSnZn alloy powder + CuSn alloy powder + Cu powder is used. The form is the basic material. By adjusting the parameters of the atomization process, the particle shape is irregular, the hollowness of the particles is improved, and the pre-alloyed shape is regular and porous, and the loose specific density of the hollowness is lower than 2.0g/cm³. powder;

The process control measures in the production of the low loose ratio pre-alloyed powder include the following steps:

(1) The degree of superheat of the metal melt: the greater the degree of superheat, the smaller the surface tension of the molten metal, the easier it is for the first droplet to form, and the generated particles are finer, but the time required for cooling is longer, the irregularity of the metal is reduced, and the looseness Ratio;

(2) Cooling water level: The cooling water level is low, the distance of particles flying in the air is long, and the irregularity is reduced. When the superheating degree is low and the atomization medium flow rate is large, the influence is not great, as long as the cooling water level does not affect the atomization process. possibly high;

(3) The structure of the nozzle and the related size: Under the same conditions, the structure of the nozzle is different, and the state of the atomizing medium and the metal melt is completely different when the metal is atomized, which directly affects the atomization effect. For the free fall type Nozzles generally have "V"-shaped plate type, cone, annular hole, annular seam and other structural forms. Using "V"-shaped plate type nozzles cannot form a closed atomization area during atomization, and the metal melt is wavy before atomization. Belt, after atomization, the particle size is large and the composition rate is low. The annular seam nozzle is difficult to process, the combined abrasive tool structure requires high requirements during installation, and the concentricity is too low, resulting in uneven distribution and non-focus of the atomized medium, and effective atomization cannot be carried out. Therefore, the annular hole structure is more reasonable. To achieve the process purpose, The ring hole structure must meet the following requirements: A. The hole diameter is small, the holes are evenly distributed, and the holes are fully focused, which can form a closed atomization area; B. The ring hole resistance of the nozzle is small. Under the same atomization pressure, the speed of the atomized medium at the nozzle outlet increases , high subdivision rate, sufficient atomization; C atomization top angle is reasonable, large atomization top angle, small jet distance, reduced irregularity, no obvious particle size change, high efficiency, but too large atomization top angle, easy to block nozzle;

(4) Atomization pressure: the speed of the water jet. When the atomization pressure is less than 7MPa, the greater the pressure, the smaller the particle size. When the pressure is less than 7MPa, the pressure has little effect on the particle size. However, when the degree of superheat is small, the atomization pressure has an impact on the particle size and irregularity, and the atomization pressure is high, and the particle size and irregularity increase. To increase the speed of the water jet, on the one hand, increase the atomization pressure, and on the other hand, reduce the resistance of the nozzle, by reducing the aspect ratio of the nozzle and improving the smoothness of the inner surface of the nozzle;

(5) Water flow rate: Although the energy actually used to produce dispersed powder particles is a small part of the energy consumed in the atomization process, a larger water flow rate can better reduce the humidity of the crushed powder and slow down the spheroidization. Decreasing the loose ratio has little effect on particle size.

Embodiment three:

The method for realizing the high green strength alloy powder in the high green body high stability environment-friendly diffusion tin-zinc-copper powder comprises the following steps:

(1) Using secondary resources such as high-purity copper, zinc and copper-tin alloy scraps as raw materials, the metal solution is obtained by melting in an induction furnace, and the metal solution is degassed and deslagged by blowing argon at the bottom of the furnace, and then left to stand Slag, so that the impurity content in the melt is less than 0.2%, the metal solution is then passed through a special nozzle, and copper powder and copper-tin-zinc alloy powder are prepared by water atomization;

(2) Water-atomized copper or copper alloy powder has a small amount of oxidation on the surface, so the oxidation-reduction process is used to modify the water-atomized copper powder and copper-tin-zinc alloy powder to further improve its performance. Oxidation-reduction process is adopted: the oxidation temperature is 300-500°C, and the oxidation time is 2-4h. According to the oxidation process, during the oxidation process, after oxidation, the reduction is carried out in hydrogen, and the reduction temperature is 400-600°C. Chemical reaction equation:

Oxidation reaction: 2M (metal) + O2 = 2MO

Reduction reaction: MO+H2=M+H2O

The oxidation-reduction process conforms to the thermodynamic theorem. According to the thermodynamic temperature map, it can be consulted, in which copper is preferentially oxidized. In copper alloys, after oxidation, the volume of oxygen occupies a certain position in the particles, resulting in the growth of the particles. Then after reduction, it forms a porous structure, and an appropriate amount of special lubricant is added through the "solid-solid" two-phase thermal diffusion process to improve the green performance of the product. Aiming at the influence of process parameters on powder properties in this process, the phase transition mechanism and interface reaction process in the thermal diffusion process are studied, which is the integration optimization and demonstration of tin-zinc-copper powder technology. The alloy powder treated with special lubricant can have a green forming pressure of more than 12MPa.

Embodiment four:

The method for reducing segregation degree and improving performance in the high-green body, high-stability, and environment-friendly diffusion tin-zinc-copper powder is the method of reducing the specific gravity segregation degree: changing the traditional solidification and atomization process, adopting the top-down solidification and atomization technology, through Adjust the parameters such as the temperature and angle of the atomizer, reverse the combination order of the primary crystals, first solidify tin and zinc with low melting points, and then solidify copper with high melting points, and form grain fusions of different metal materials during fusion. Through the mechanism principle of thermodynamics + kinetics, the secondary fusion is realized to reduce the specific gravity segregation.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (4)

1. a kind of preparation method of high green compact high stability environmental protection diffusion type tin zinc-copper powder, it is characterised in that: a kind of Gao Sheng The preparation method of base high stability environmental protection diffusion type tin zinc-copper powder the following steps are included:

(1) raw material is chosen: it is spare to choose the secondary resources such as high-purity copper, zinc and the copper-tin alloy leftover pieces of certain mass number；

(2) low pine is than the formation of prealloy powder: high-purity copper powder of low apparent density and Albaloy powder are prepared by using water atomization, Parameter by adjusting atomization process improves the hollowness of particle so that granule-morphology is irregular, and the regular shape of generation is porous Shape, the loose specific density of Multihollow degree is lower than the pre-alloyed powder of 2.0g/cm3；

(3) high green is realized: by the way that suitable extraordinary lubricant is added in " solid-solid " two-phase thermal diffusion process, to improve The green compact performance of product, by being tin zinc to the phase transition mechanism and the expansion research of interfacial reaction process in thermal diffusion process The optimization of copper powder Integration ofTechnology and demonstration, using the alloyed powder of special lubricant processing, its green compact typed pressure can achieve 12MPa More than；

(4) degree of segregation improving performance is reduced: by the microsegregation performance and gravity segregation performance during change powder compacting Two key factors reduce segregation performance, and Main is to change crystal grain atom using dynamics+Thermodynamic Mechanism principle Spacing is spread to reduce microsegregation degree；Using reverse order freezing method, changes mother liquor and match the solidification sequence reduction material of liquid The gravity segregation of material.

2. a kind of preparation method of high green compact high stability environmental protection diffusion type tin zinc-copper powder according to claim 1, special Sign is: low pine is more raw using diffusion technique is consolidated than prealloy powder in the high green compact high stability environmental protection diffusion type tin zinc-copper powder The tin zinc-copper powder of production is in the selection of material, based on CuSnZn alloyed powder+CuSn alloyed powder+Cu powder combining form Material, so that granule-morphology is irregular, improves the hollowness of particle, the shape rule of generation by adjusting the parameter of atomization process Then cavernous, the loose specific density of Multihollow degree is lower than the pre-alloyed powder of 2.0g/cm3；

It is described it is low pine than prealloy powder production in Countermeasures the following steps are included:

The degree of superheat of metal bath: the degree of superheat is bigger, and molten metal surface tension is small, the easier formation of first time drop, generation Particle is thin, but the time of cooling requirement is long, and the degree of irregularity of metal reduces, Song Bigao；

Chilled water: chilled water is low, the distance that particle flies in the sky, and degree of irregularity reduces, when the lower degree of superheat, mist When change rate-of flow is big, influence less, as long as it is as high as possible not influence atomization process chilled water；

The structure of nozzle is to relevant size: under other identical conditions, the structure type of nozzle is different, when metal atomization The situation of atomizing medium and metal bath is entirely different, directly affects atomizing effect, for free fall type nozzle, generally has The structure types such as " V " shape is board-like, taper, annular distance, circumferential weld cannot form closed mist in atomization using " V " shape plate nozzle Change region, is in wavy band before metal bath atomization, granularity is big after atomization, and ingredient rate is low；

Circumferential weld nozzle processing difficulties, combination abrasive structure require height during installation, and concentricity is too low, cause atomizing medium distribution not , out-focus not can be carried out effective atomization, thus ring pore structures are relatively reasonable, to reach technique purpose, and ring pore structures will meet Claimed below: the aperture A is small, pore size distribution is uniform, hole sufficiently focuses, and can form closed nebulization region；B nozzle annular distance resistance is small, Under identical atomizing pressure, jet expansion atomizing medium speed is improved, and subdivision rate is high, and atomization is abundant；C atomization item angle is reasonable, It is atomized that apex angle is big, and stream distance is small, degree of irregularity reduces, and granularity variation is unobvious, and it is high-efficient, and it is excessive to be atomized apex angle, easily Plug nozzle；

Atomizing pressure: i.e. water jet speed；

When atomizing pressure is less than 7MPa, pressure is bigger, and granularity is smaller, when pressure is 7MPa, shadow of the pressure to granularity It rings little；

But when the degree of superheat is smaller, atomizing pressure all has an impact to granularity and degree of irregularity, and atomizing pressure is big, fine size, irregular It improves；

Water jet speed is improved, atomizing pressure is on the one hand improved, on the other hand reduces nozzle resistance, by the length for reducing nozzle Diameter ratio improves inner nozzle surface finish and realizes；

Water flow: although the energy for being actually used in the powder particle of production dispersion is a small portion of consumed energy in atomization process Point, biggish water flow can preferably reduce the humidity of crushed powder, slow down nodularization, reduce loose ratio, little to particle size influences.

3. a kind of preparation method of high green compact high stability environmental protection diffusion type tin zinc-copper powder according to claim 1, special Sign is: in the high green compact high stability environmental protection diffusion type tin zinc-copper powder implementation method of high green alloyed powder include with Lower step:

(1) using secondary resources such as high-purity copper, zinc and copper-tin alloy leftover pieces as raw material, fusing obtains metal in electric induction furnace Solution is carried out degasification deslagging to metallic solution, is then allowed to stand slag hitting, keeps impurity content in melt small by furnace bottom gon technics In 0.2%, then metallic solution passes through special nozzle, prepares copper powder and Albaloy powder using water atomization；

(2) there are small amounts on water atomization copper or copper alloy powder, surface, so using oxidation --- and reducing process is to water atomization Copper powder and Albaloy powder are modified, and are further improved its performance；

Use oxidationreduction technique: wherein oxidizing temperature is 300-500 DEG C, oxidization time 2-4h, according to oxidation process In, it wherein in oxidation process, after oxidation, is restored in hydrogen, reduction temperature is 400-600 DEG C, chemical reaction side Journey:

Oxidation reaction: 2M (metal)+O2=2MO

Reduction reaction: MO+H2=M+H2O

Wherein oxidation-reduction process meets thermodynamics theorem, according to thermodynamic temperature map, can consult, wherein the preferential oxygen of copper Change, in copper alloy, wherein the volume of oxygen occupies certain position in the grain, leads to growing up for particle after due to oxidation；

Then after passing through reduction, a kind of porous structure is formed, by the way that suitable spy is added in " solid-solid " two-phase thermal diffusion process Kind lubricant, to improve the green compact performance of product；

Phase transition mechanism and boundary for technological parameter during this to the affecting laws of powder characteristic, in thermal diffusion process The expansion research of face reaction process, optimizes and is demonstrated for tin zinc-copper powder Integration ofTechnology；

Using the alloyed powder of special lubricant processing, its green compact typed pressure can achieve 12MPa or more.

4. a kind of preparation method of high green compact high stability environmental protection diffusion type tin zinc-copper powder according to claim 1, special Sign is: in the high green compact high stability environmental protection diffusion type tin zinc-copper powder reduce degree of segregation improving performance implementation method be than Weight degree of segregation reduces method: changing traditional solidification atomization process, using top-down solidification atomization technique, by adjusting mist Change the parameters such as temperature, the angle of device, Inversion is carried out to the built-up sequence of nascent crystalline substance, first solidifies low-melting tin, zinc, it is rear solidifying Gu the high copper of fusing point generates the crystal grain fusion of different metal material in fusion, passes through thermodynamics+dynamic (dynamical) Mechanism Primary Reason realizes that secondary fusion reduces gravity segregation.