阅读说明：本技术 一种CoCrFeNiTi/cBN复合粉末、制备方法及其涂层 (CoCrFeNiTi/cBN composite powder, preparation method and coating thereof ) 是由 杜令忠 孙小明 兰昊 黄传兵 张伟刚 于 2021-08-26 设计创作，主要内容包括：本发明涉及一种CoCrFeNiTi/cBN复合粉末、制备方法及其涂层,属于合金粉末制备技术领域。所述复合粉末的配方由CoCrFeTi合金粉末和Ni包覆cBN粉末按质量比为3:1～4:1组成；Co、Cr、Fe、Ni和Ti的摩尔比为2～3:2～3:2～3:2～3:2～3；以Ni包覆cBN粉末的质量为100％计,cBN的质量分数为30％～50％。将Co、Cr、Fe和Ti粉末制备成CoCrFeTi合金粉末,然后将其与Ni包覆cBN粉末混匀,在保护气体保护下进行高温热扩散处理,得到产物,破碎,分级,真空干燥,得到所述复合粉末,其成分均匀、流动性好。所述复合粉末形成的涂层,其成分均匀、组织致密。(The invention relates to CoCrFeNiTi/cBN composite powder, a preparation method and a coating thereof, belonging to the technical field of alloy powder preparation. The formula of the composite powder comprises CoCrFeTi alloy powder and Ni-coated cBN powder according to the mass ratio of 3: 1-4: 1; the molar ratio of Co, Cr, Fe, Ni and Ti is 2-3: 2-3; the mass fraction of cBN is 30-50% based on 100% of the mass of the Ni-coated cBN powder. Preparing Co, Cr, Fe and Ti powder into CoCrFeTi alloy powder, then uniformly mixing the CoCrFeTi alloy powder with Ni-coated cBN powder, carrying out high-temperature thermal diffusion treatment under the protection of protective gas to obtain a product, crushing, grading and vacuum drying to obtain the composite powder, wherein the composite powder is uniform in components and good in fluidity. The coating formed by the composite powder has uniform components and compact structure.)

1. A CoCrFeNiTi/cBN composite powder is characterized in that: the formula of the composite powder consists of CoCrFeTi alloy powder and Ni-coated cBN powder;

the mass ratio of the CoCrFeTi alloy powder to the Ni-coated cBN powder is 3: 1-4: 1;

the molar ratio of Co, Cr, Fe, Ni and Ti is 2-3: 2-3;

the mass fraction of cBN is 30-50% based on 100% of the mass of the Ni-coated cBN powder.

2. The CoCrFeNiTi/cBN composite powder according to claim 1, wherein: the mass ratio of the CoCrFeTi alloy powder to the Ni-coated cBN powder was 3: 1.

3. The CoCrFeNiTi/cBN composite powder according to claim 1, wherein: the mass fraction of cBN was 40% based on the mass of the Ni-coated cBN powder as 100%.

4. The CoCrFeNiTi/cBN composite powder according to claim 1, wherein: the mass ratio of the CoCrFeTi alloy powder to the Ni-coated cBN powder is 3: 1;

the mass fraction of cBN was 40% based on the mass of the Ni-coated cBN powder as 100%.

5. A method for producing the CoCrFeNiTi/cBN composite powder according to any one of claims 1 to 4, characterized in that:

(1) uniformly mixing four metal powders of Co, Cr, Fe and Ti, and carrying out ball milling under the protection of protective gas to prepare CoCrFeTi alloy powder;

the purity of the four metal powders of Co, Cr, Fe and Ti is more than 99%, and the particle sizes are all 100-400 meshes;

the protective gas is nitrogen or inert gas;

the ball milling parameters were as follows: the ball milling speed is 100 r/min-400 r/min, the ball material mass ratio is 1: 1-15: 1, and the ball milling time is 2 h-48 h;

(2) uniformly mixing CoCrFeTi alloy powder and Ni-coated cBN powder, carrying out high-temperature thermal diffusion treatment under the protection of protective gas, wherein the treatment temperature is 860-900 ℃, the heat preservation time is 2-6 h, and obtaining a product after the heat preservation is finished;

the protective gas is more than one of hydrogen and argon, and the purity of the hydrogen is more than 99.99 percent;

(3) crushing, sieving and grading the product to obtain powder with the grain size of 100-325 meshes, and drying in vacuum to obtain CoCrFeNiTi/cBN composite powder;

the temperature of vacuum drying is 60-150 ℃ and the time is 2-4 h.

6. The method for preparing a CoCrFeNiTi/cBN composite powder according to claim 5, wherein the method comprises the steps of: in the step (1):

the protective gas is argon;

the ball milling speed is 350r/min, the ball material mass ratio is 10:1, and the ball milling time is 6 h.

7. The method for preparing a CoCrFeNiTi/cBN composite powder according to claim 5, wherein the method comprises the steps of: in the step (2):

the protective gas is hydrogen with the purity of more than 99.999 percent;

the temperature of the high-temperature thermal diffusion treatment is 900 ℃, and the heat preservation time is 6 h.

8. The method for preparing a CoCrFeNiTi/cBN composite powder according to claim 5, wherein the method comprises the steps of: in the step (1):

the protective gas is argon;

the ball milling speed is 350r/min, the ball material mass ratio is 10:1, and the ball milling time is 6 h;

in the step (2):

the protective gas is hydrogen with the purity of more than 99.999 percent;

the temperature of the high-temperature thermal diffusion treatment is 900 ℃, and the heat preservation time is 6 h.

9. A CoCrFeNiTi/cBN coating, characterized in that the coating is formed by spraying the CoCrFeNiTi/cBN composite powder according to any one of claims 1 to 4 on a substrate by means of atmospheric plasma spraying.

10. A cocrfenii/cBN coating according to claim 9, characterised in that: the parameters of the atmospheric plasma spraying are as follows: the argon flow is 30L/min-50L/min, the hydrogen flow is 1.4L/min-5.0L/min, the current is 450A-600A, the voltage is 50V-70V, and the spraying distance is 70 mm-110 mm.

Technical Field

The invention relates to CoCrFeNiTi/cBN composite powder, a preparation method and a coating thereof, belonging to the technical field of alloy powder preparation.

Background

High Entropy Alloys (HEA), also known as HEA, are alloys formed from 5 or more than 5 equal or approximately equal amounts of metals. In recent years, the concept of these alloys is still new, and the understanding of these alloys is still in the first stage, and the application thereof in various application fields is still actively studied. HEA-based coatings are of great interest due to their unique properties. In particular, the single-phase CoCrFeNi-based HEA is an ideal choice for chemical and nuclear reactor coating materials and the like. However, the wear resistance of high-entropy alloys, etc. is to be improved against a large number of application scenarios. In order to solve this problem, research is actively being conducted to improve the wear resistance of high-entropy alloys by doping the alloys with ceramic reinforcing phases.

At present, the high-entropy alloy/ceramic composite coating (namely the composite coating consisting of the high-entropy alloy and the ceramic) is mainly prepared by methods such as hot-pressing sintering, laser cladding and the like. However, due to the limitations of many ceramic phases, their introduction has limited the conventional methods such as atmospheric plasma spraying in the preparation of high entropy alloy/ceramic composite coatings. In the preparation process of the coating, the cubic boron nitride (cBN) has serious loss and agglomeration in the process of atmospheric plasma spraying, so that the components and the performance of the final high-entropy alloy/ceramic phase coating are influenced.

Therefore, how to reduce the loss and agglomeration of cBN in the atmospheric plasma spraying process and prepare high-entropy alloy/ceramic composite powder with uniform components, controllable granularity and good fluidity, and the coating prepared from the composite powder has good performances of wear resistance, corrosion resistance and the like, is a difficult problem to be solved.

Disclosure of Invention

In order to solve the above problems, an object of the present invention is to provide a cocrfenii/cBN composite powder, that is, a composite powder composed of a high-entropy alloy cocrfenii and cBN, which has uniform components, controllable particle size, and good flowability.

The second purpose of the invention is to provide a preparation method of the CoCrFeNiTi/cBN composite powder.

The invention also aims to provide a CoCrFeNiTi/cBN coating, the coating is formed by spraying the CoCrFeNiTi/cBN composite powder on a substrate, and the coating has uniform components and compact structure.

To achieve the object of the present invention. The following technical scheme is provided.

A CoCrFeNiTi/cBN composite powder, the formula of which consists of CoCrFeTi alloy powder and Ni-coated cBN powder.

Wherein the mass ratio of the CoCrFeTi alloy powder to the Ni-coated cBN powder is (3:1) - (4: 1).

Preferably, the mass ratio of the CoCrFeTi alloy powder to the Ni-coated cBN powder is 3: 1.

The composite powder contains Co, Cr, Fe, Ni and Ti in a molar ratio of (2-3) to (2-3).

The mass fraction of cBN is 30-50% based on 100% of the mass of the Ni-coated cBN powder.

Preferably, the mass fraction of cBN is 40% based on 100% by mass of the Ni-coated cBN powder.

The invention relates to a preparation method of CoCrFeNiTi/cBN composite powder, which comprises the following steps:

(1) and uniformly mixing four metal powders of Co, Cr, Fe and Ti, and carrying out ball milling under the protection of protective gas to prepare CoCrFeTi alloy powder.

Wherein the purity of the four metal powders of Co, Cr, Fe and Ti is more than 99%, and the particle diameters are all 100-400 meshes.

The protective gas is nitrogen or inert gas.

The ball milling parameters were as follows: the ball milling speed is 100 r/min-400 r/min, the ball material mass ratio is (1:1) - (15:1), and the ball milling time is 2 h-48 h.

Preferably, the protective gas is argon.

Preferably, the ball milling speed is 350r/min, the ball-material mass ratio is 10:1, and the ball milling time is 6 h.

(2) The method comprises the following steps of processing CoCrFeTi alloy powder and Ni-coated cBN powder by adopting a high-temperature thermal diffusion technology to interpenetrate the two powders, and specifically comprises the following steps: the CoCrFeTi alloy powder and the Ni-coated cBN powder are uniformly mixed, high-temperature thermal diffusion treatment is carried out under the protection of protective gas, the treatment temperature is 860-900 ℃, the heat preservation time is 2-6 h, and after the heat preservation is finished, a product is obtained.

Wherein the protective gas is more than one of hydrogen and argon, and the purity of the hydrogen is more than 99.99%.

Preferably, the protective gas is hydrogen with a purity of 99.999% or more.

Preferably, the temperature of the high-temperature thermal diffusion treatment is 900 ℃, and the holding time is 6 h.

(3) And (3) taking out the product obtained in the step (2), crushing, sieving and grading to obtain powder with the particle size of 100-325 meshes, and drying in vacuum to obtain the CoCrFeNiTi/cBN composite powder, wherein the composite powder is completely alloyed powder.

Wherein the temperature of vacuum drying is 60-150 ℃ and the time is 2-4 h.

The CoCrFeNiTi/cBN coating is formed by spraying the CoCrFeNiTi/cBN composite powder on a substrate by adopting an air plasma spraying method, and the coating has uniform components, compact structure, wear resistance and corrosion resistance.

The parameters of the atmospheric plasma spraying are as follows: the argon flow is 30L/min-50L/min, the hydrogen flow is 1.4L/min-5.0L/min, the current is 450A-600A, the voltage is 50V-70V, and the spraying distance is 70 mm-110 mm.

Advantageous effects

(1) The invention provides CoCrFeNiTi/cBN composite powder which is uniform in component and good in flowability, and shows that the spraying effect is good when the CoCrFeNiTi/cBN composite powder is sprayed on the surface of a substrate. By introducing Ni-coated cBN powder into the composite powder, the overall quality of a ceramic phase is improved, and the Ni has an outer layer protection effect on the cBN, so that the loss and agglomeration of the cBN are greatly reduced in the spraying process of the composite powder, and the sprayed coating is ensured to have good wear resistance and corrosion resistance.

In addition, the mass fraction of cBN in the Ni-coated cBN powder is 30-50%, so that the composite powder has good fluidity and is beneficial to the implementation of atmospheric plasma spraying. The coating obtained by spraying the composite powder on a substrate has compact structure and few defects. If the mass fraction of cBN in the Ni-coated cBN powder is less than 30% or more than 50%, a composite powder having good flowability cannot be obtained, and the cBN ceramic phase in the coating layer obtained by the preparation is not uniformly distributed and the loss of components is severe.

(2) The invention provides CoCrFeNiTi/cBN composite powder, the content of each metal element of the composite powder can be regulated and controlled in a corresponding range, and the obtained composite powder can form a single structure, so that the wear resistance and the corrosion resistance of a coating are further improved; the composite powder may be formulated as required for density, particle size, flowability and other properties.

(3) The invention provides a preparation method of CoCrFeNiTi/cBN composite powder, which is simple and low in preparation cost, and the prepared powder has high success rate and can be prepared into completely alloyed powder with different component contents.

(4) The invention provides a CoCrFeNiTi/cBN coating which is compact in structure, uniform in components, less in defects and uniform in distribution of a ceramic reinforcing phase (namely cBN).

Drawings

FIG. 1 is a cross-sectional scanning electron micrograph of the CoCrFeNiTi/cBN composite powder produced in example 1.

FIG. 2 is a cross-sectional scanning electron micrograph of the CoCrFeNiTi/cBN composite coating produced in example 1.

FIG. 3 is a cross-sectional scanning electron micrograph of the CoCrFeNiTi/cBN composite powder produced in example 2.

FIG. 4 is a cross-sectional scanning electron micrograph of the CoCrFeNiTi/cBN composite coating made in example 2.

Detailed Description

The invention is described in detail below with reference to the drawings and specific examples, but the invention is not limited thereto.

In the following examples:

the atmospheric plasma spraying adopts APS-2000K type plasma spraying equipment.

The microstructures of the composite powder and the coating layer obtained in examples 1 and 2 were observed by a scanning electron microscope of JSM-7001F, a Japanese JEOL company.

The purity of the four metal powders of Co, Cr, Fe and Ti is more than 99.99%, and the particle diameters are all 100-400 meshes.

Example 1

A method for preparing CoCrFeNiTi/cBN composite powder comprises the following steps:

(1) and uniformly mixing four metal powders of Co, Cr, Fe and Ti according to a molar ratio of Co to Cr to Fe to Ti of 4 to 5, and performing ball milling under the protection of argon to prepare CoCrFeTi alloy powder.

The ball milling parameters are as follows: the ball milling speed is 300r/min, the ball material mass ratio is 10:1, the ball milling time is 24h, and stainless steel balls with the sizes of 10mm, 5mm and 3mm are adopted to perform ball milling in a stainless steel tank according to the mass ratio of 1:5: 20.

(2) Uniformly mixing CoCrFeTi alloy powder and Ni-coated cBN powder according to the mass ratio of 3:1, carrying out high-temperature thermal diffusion treatment under the protection of hydrogen with the purity of 99.99%, wherein the treatment temperature is 900 ℃, the heat preservation time is 6 hours, and cooling to room temperature after the heat preservation is finished to obtain a product;

the mass fraction of cBN was 30% based on the mass of the Ni-coated cBN powder as 100%.

(3) And (3) taking out the product obtained in the step (2), crushing by using a disc crusher, sieving and grading to obtain powder with the particle size of 100-325 meshes, and vacuum drying at 80 ℃ for 2h to obtain the fully alloyed CoCrFeNiTi/cBN composite powder.

The composite powder prepared in the embodiment is sprayed on a GH4033 high-temperature alloy substrate by an atmospheric plasma spraying method to form a composite coating, and the conditions of the atmospheric plasma spraying are as follows: the flow of argon gas is 30L/min, the flow of hydrogen is 2L/min, the current is 500A, the voltage is 55V, and the spraying distance is 80mm, so that the CoCrFeNiTi/cBN composite coating is obtained.

The CoCrFeNiTi/cBN composite powder produced in this example was tested as follows:

(1) the microstructure of the composite powder was observed by a scanning electron microscope, and the result is shown in FIG. 1, from which it can be seen that the composite powder was spheroidal, the powder diameter was small, and the powder diameter was 60 μm to 80 μm.

(2) XRD phase analysis is carried out on the composite powder by an X-ray diffractometer, and the result shows that the composite powder is single-phase powder.

(3) Testing the apparent density and the fluidity of the composite powder by adopting a powder fluidity tester, wherein the apparent density of the composite powder is 2.01g/cm³The flow behavior was 55s/50g, and it was found that the flowability of the composite powder was good, further, the sprayability of the composite powder was good.

The microstructure of the resulting CoCrFeNiTi/cBN composite coating was observed by scanning electron microscopy and the results are shown in fig. 2, from which it can be seen that the composite coating had a dense texture, few defects and the added cBN was uniformly distributed.

Example 2

A method for preparing CoCrFeNiTi/cBN composite powder comprises the following steps:

(1) and uniformly mixing four metal powders of Co, Cr, Fe and Ti according to the molar percentage of Co to Cr to Fe to Ti to be 1 to 1, and performing ball milling under the protection of argon to prepare the CoCrFeTi alloy powder.

The ball milling parameters are as follows: the ball milling speed is 360r/min, the ball material mass ratio is 15:1, the ball milling time is 48h, and stainless steel balls with the sizes of 10mm, 5mm and 3mm are adopted to perform ball milling in a stainless steel tank according to the mass ratio of 1:5: 20.

(2) Uniformly mixing CoCrFeTi alloy powder and Ni-coated cBN powder according to the mass ratio of 4:1, carrying out high-temperature thermal diffusion treatment under the protection of hydrogen with the purity of 99.99%, wherein the treatment temperature is 900 ℃, the heat preservation time is 6h, and cooling to room temperature after the heat preservation is finished to obtain a product.

The mass fraction of cBN was 50% based on the mass of the Ni-coated cBN powder as 100%.

(3) And (3) taking out the product obtained in the step (2), crushing by using a disc crusher, sieving and grading to obtain powder with the particle size of 100-325 meshes, and vacuum drying at 80 ℃ for 4h to obtain the fully alloyed CoCrFeNiTi/cBN composite powder.

The composite powder prepared in the embodiment is sprayed on a GH4033 high-temperature alloy substrate by an atmospheric plasma spraying method to form a composite coating, and the conditions of the atmospheric plasma spraying are as follows: the flow rate of argon gas was 40L/min, the flow rate of hydrogen was 4L/min, the current was 550A, the voltage was 60V, and the spraying distance was 100mm, to obtain the CoCrFeNiTi/cBN composite coating of this example.

The CoCrFeNiTi/cBN composite powder produced in this example was tested as follows:

(1) the microstructure of the composite powder was observed by a scanning electron microscope, and the result is shown in FIG. 3, from which it can be seen that the composite powder was spheroidal, the powder diameter was small, and the powder diameter was 60 μm to 80 μm.

(2) XRD phase analysis is carried out on the composite powder by an X-ray diffractometer, and the result shows that the composite powder is single-phase powder.

(3) Testing the apparent density and the fluidity of the composite powder by adopting a powder fluidity tester, wherein the apparent density of the composite powder is 2.03g/cm³The flow behavior was 50s/50g, and it was found that the flowability of the composite powder was good, further, the sprayability of the composite powder was good.

The microstructure of the resulting CoCrFeNiTi/cBN composite coating was observed by scanning electron microscopy and the results are shown in fig. 4, from which it can be seen that the composite coating had a dense texture, few defects and the added cBN was uniformly distributed.

Comparative example 1

This comparative example is different from example 1 in that the Ni-coated cBN powder used was 60% by mass of cBN, based on 100% by mass of the Ni-coated cBN powder, and the rest was the same as example 1.

XRD phase analysis of the composite powder obtained in this comparative example using an X-ray diffractometer showed that a completely alloyed single-phase powder was not formed in the composite powder obtained in this comparative example.

Scanning electron microscope is used for scanning morphology analysis of the composite coating prepared by the comparative example, and the result shows that the cBN ceramic phase is not uniformly distributed and the component loss is serious.

Comparative example 2

This comparative example is different from example 1 in that the Ni-coated cBN powder used was the same as example 1 except that the mass fraction of cBN was 70% based on 100% by mass of the Ni-coated cBN powder.

XRD phase analysis of the composite powder obtained in this comparative example using an X-ray diffractometer showed that a completely alloyed single-phase powder was not formed in the composite powder obtained in this comparative example.

Scanning electron microscope is used for scanning morphology analysis of the composite coating prepared by the comparative example, and the result shows that the cBN ceramic phase is not uniformly distributed and the component loss is serious.

The present invention includes, but is not limited to, the above-described embodiments, and any equivalent substitutions or partial modifications made under the spirit and principle of the present invention are considered to be within the scope of the present invention.