阅读说明：本技术 一种高熵合金粉末、高电阻涂层及其制备方法和应用 (High-entropy alloy powder, high-resistance coating, and preparation method and application thereof ) 是由 周正 张硕 姚海华 郭星晔 谈震 吴旭 邵蔚 王国红 贺定勇 于 2020-06-17 设计创作，主要内容包括：本发明涉及一种高熵合金粉末、高电阻涂层及其制备方法和应用,包含按质量百分含量的以下成分：镍17～25％,钴14～25％,铬15～20％,锰13～20％,铁为余量,所述高熵合金粉末用于高电阻加热涂层的制备。本发明提供的高电阻涂层材料使涂层获得单一相结构的同时,提高涂层电阻,实现加热效率的提升,同时保证服役可靠性,具有广阔的应用前景。(The invention relates to high-entropy alloy powder, a high-resistance coating, and a preparation method and application thereof, wherein the high-entropy alloy powder comprises the following components in percentage by mass: 17-25% of nickel, 14-25% of cobalt, 15-20% of chromium, 13-20% of manganese and the balance of iron, wherein the high-entropy alloy powder is used for preparing a high-resistance heating coating. The high-resistance coating material provided by the invention enables the coating to obtain a single-phase structure, improves the coating resistance, realizes the improvement of the heating efficiency, ensures the service reliability, and has wide application prospect.)

1. The high-entropy alloy powder is characterized by comprising the following components in percentage by mass: 17-25% of nickel, 14-25% of cobalt, 15-20% of chromium, 13-20% of manganese and the balance of iron, wherein the high-entropy alloy powder is used for preparing a high-resistance heating coating.

2. A high entropy alloy powder according to claim 1, characterized in that: the manganese accounts for 14-18% by mass.

3. The high-resistance coating is characterized by being prepared from high-entropy alloy powder through a thermal spraying method, wherein the high-entropy alloy powder comprises the following components in percentage by mass: 17-25% of nickel, 14-25% of cobalt, 15-20% of chromium, 13-20% of manganese and the balance of iron.

4. The high-resistance coating according to claim 3, wherein the manganese is contained in an amount of 14 to 18% by mass.

5. The high-resistance coating according to claim 3 or 4, wherein the particle size of the high-entropy alloy powder is in the range of 25 to 55 μm.

6. The high-resistance coating according to any one of claims 3 to 5, comprising the following components in mass percent: 17-21% of nickel, 12-21% of cobalt, 16-19% of chromium, 14-19% of manganese and the balance of iron.

7. A method for producing a high-resistance coating layer as claimed in any one of claims 3 to 6, characterized by comprising the step of thermal spraying: and preparing the high-resistance coating from the high-entropy alloy powder by adopting an atmospheric plasma spraying method.

8. The method of claim 7, wherein the spray coating process parameters are: current: 450-600A, argon flow: 30-40L/min, hydrogen flow: 10-18L/min, powder feeding rate: 55-80g/min, spraying distance: 120-135 mm.

9. The production method according to claim 7 or 8, characterized in that the high-entropy alloy powder is produced by a nitrogen gas atomization method; the raw materials for preparing the high-entropy alloy powder are selected from pure metal blocks of nickel, cobalt, chromium, manganese and iron or alloy materials, wherein the purity of the pure metal blocks is more than 99.0 wt.%, and the alloy materials are selected from one or more of nickel-chromium, nickel-cobalt-chromium and iron-manganese.

10. The high-entropy alloy powder of claim 1 or 2 or the high-resistance coating of any one of claims 3 to 6 or the high-resistance coating produced by the method of any one of claims 7 to 9 is useful for applications in the field of electrical heating.

Technical Field

The invention relates to the technical field of electric heating materials, in particular to high-entropy alloy powder, a high-resistance coating, and a preparation method and application thereof.

Background

The traditional alloy usually takes a single element as a main element, but the high-entropy alloy proposed in recent years breaks through the traditional design concept, adopts multiple elements as main elements, and the novel alloy design endows the high-entropy alloy with a series of characteristics different from the traditional alloy, including a high-entropy effect, a delayed diffusion effect, a lattice distortion effect, a cocktail effect and the like. Therefore, the high-entropy alloy has excellent properties such as good strength, hardness, wear resistance, corrosion resistance and thermal stability. At present, the preparation and research of the high-entropy alloy mainly focuses on the block structural material, relatively few researches related to the coating are carried out, the wear-resistant and corrosion-resistant performances of the coating are mainly researched, and the adopted preparation methods are mainly processes such as laser/plasma cladding and the like. As is well known, metals and alloy materials are considered good conductors, so researchers have had relatively limited interest in the electrothermal performance of high entropy alloys, particularly for thermal spray coatings. At present, the conventional electrothermal alloy material is mainly resistance wire materials of nickel-chromium or iron-chromium-aluminum alloy, but the resistance of the resistance wire materials is relatively low, so that the heating efficiency is low, the reliability is insufficient, and the like. There is a need to develop a new high resistance alloy heating coating and a method for preparing the same.

Disclosure of Invention

In order to solve the technical problems, the embodiment of the invention provides high-entropy alloy powder, a high-resistance coating and a preparation method thereof. The high-resistance (heating) coating material provided by the embodiment of the invention enables the coating to obtain a single-phase structure, improves the coating resistance, realizes the improvement of the heating efficiency, ensures the service reliability, and has wide application prospect.

One aspect of the invention provides high-entropy alloy powder, which comprises the following components in percentage by mass: 17-25% of nickel, 14-25% of cobalt, 15-20% of chromium, 13-20% of manganese and the balance of iron, wherein the high-entropy alloy powder is used for preparing a high-resistance heating coating.

According to some preferred embodiments of the invention, the manganese is 14-18% by mass.

In the invention, the inevitable impurities in the high-entropy alloy powder comprise N, P and S, and the total content of the impurities is controlled to be less than 0.5% so as not to influence the alloy composition and performance obviously.

The invention also provides a high-resistance coating, which is prepared by hot spraying high-entropy alloy powder, wherein the high-entropy alloy powder comprises the following components in percentage by mass: 17-25% of nickel, 14-25% of cobalt, 15-20% of chromium, 13-20% of manganese and the balance of iron.

According to some preferred embodiments of the invention, the manganese is 14-18% by mass.

According to some preferred embodiments of the present invention, the high-entropy alloy powder has a particle size ranging from 25 to 55 μm.

According to some preferred embodiments of the present invention, the following ingredients are contained in mass percent: 17-21% of nickel, 12-21% of cobalt, 16-19% of chromium, 14-19% of manganese and the balance of iron. The invention adopts high-entropy alloy powder components with specific chemical components and mass ratio, is favorable for ensuring the structural characteristics of the coating, further reduces the porosity and oxygen content of the coating material, and simultaneously improves the bonding strength, resistivity and other properties of the coating.

In another aspect, the present invention provides a method for preparing the high resistance coating, including the steps of thermal spraying: and preparing the high-resistance coating from the high-entropy alloy powder by adopting an atmospheric plasma spraying method.

According to some preferred embodiments of the invention, the spray process parameters are: current: 450-600A, argon flow: 30-40L/min, hydrogen flow: 10-18L/min, powder feeding rate: 55-80g/min, spraying distance: 120-135 mm.

According to some preferred embodiments of the present invention, the high-entropy alloy powder is prepared by a nitrogen atomization method; the raw materials for preparing the high-entropy alloy powder are selected from pure metal blocks of nickel, cobalt, chromium, manganese and iron or alloy materials, wherein the purity of the pure metal blocks is more than 99.0 wt.%, and the alloy materials are selected from one or more of nickel-chromium, nickel-cobalt-chromium and iron-manganese.

According to some preferred embodiments of the present invention, a method of preparing an alloy coating having high electrical resistance comprises the steps of:

(1) preparing alloy powder: preparing high-entropy alloy powder with good sphericity and a particle size range of 25-55 mu m by adopting a nitrogen atomization method;

(2) thermal spraying: the alloy powder in the step (1) is used for preparing the high-entropy alloy coating by adopting an Atmospheric Plasma Spraying (APS) process, and in the coating preparation method, the Atmospheric Plasma Spraying (APS) has the distinct process characteristics, including wide spraying material range, the materials from a low melting point to a high melting point can be sprayed, the requirement on the granularity of the spraying powder is not high, the porosity of the coating is low, oxide inclusions are few, and the like, so that the method is one of effective methods for preparing the high-entropy alloy coating. The spraying process parameters are preferably as follows: current: 450-: 30-40L/min, hydrogen flow: 10-18L/min, powder feeding rate: 55-80g/min, spraying distance: 120-135 mm. The raw materials required for preparing the alloy powder comprise nickel, cobalt, chromium, manganese and iron pure metal block materials, the purity of chemical components is more than 99.0 wt.%, or alloy materials such as nickel-chromium, nickel-cobalt-chromium, iron-manganese and the like. The spraying matrix is a metal base material.

The invention also provides application of the high-entropy alloy powder or the high-resistance coating prepared by the method in a heating coating.

In the invention, the phase structure of the high-resistance alloy coating is a single-phase solid solution, but has high resistance. The improvement of the resistance performance of the coating is benefited by the reasonable matching of the design and the preparation method of the components. The coating material is a high-entropy alloy and comprises a multi-principal-element alloy of nickel, iron, cobalt and chromium, wherein the design of several transition group metals is that the atomic radii of the transition group metals are closer to each other so as to realize better mutual solubility, so that a single-phase solid solution structure is obtained, and the material can have better process adaptability, namely has better plastic deformation capability so that the coating keeps better compactness; meanwhile, the integral resistivity can also be improved by introducing larger lattice distortion into the alloy; the combined action of nickel, cobalt and chromium elements is also beneficial to improving the integral high-temperature oxidation resistance of the coating; the necessary addition of manganese element can increase the lattice distortion of alloy system, reduce the layer fault energy and simultaneously reduce the ferromagnetic performance of coating. The overall improvement of the coating resistance is mainly obtained by the combined action of reasonable configuration of the components of the alloy and the preparation method, is not determined by any single element, but is also absent and certainly not obtained by only limited tests.

The invention has the beneficial effects that: 1) the alloy coating maintains a single-phase FCC stable phase structure; 2) the grain size of the coating reaches the nanometer level; 3) the resistivity of the coating is remarkably improved and can exceed 300 mu omega cm and is higher than that of the traditional nichrome resistance wire material (about 100-115 mu omega cm); 4) the preparation method is simple, and the processing such as casting, forging, drawing and the like in the resistance wire preparation process is not needed; 5) the coating heating efficiency and reliability are higher.

Drawings

FIG. 1 is an X-ray diffraction (XRD) spectrum of the alloy powder of example 2.

FIG. 2 is an SEM morphology of the alloy powder of example 2.

FIG. 3 is a plot of the X-ray diffraction (XRD) pattern corresponding to the coating prepared in example 2.

FIG. 4 is a SEM topography corresponding to the coating prepared in example 2.

FIG. 5 is a TEM topography corresponding to the coating prepared in example 2.

Fig. 6 is an X-ray diffraction (XRD) pattern corresponding to the coating prepared in comparative example 2.

In the above figures, FCC and Oxide represent face-centered cubic single-phase solid solutions and metal Oxide phases, respectively.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention. The examples do not show the specific techniques or conditions, according to the technical or conditions described in the literature in the field, or according to the product specifications.

In the following examples, bulk nickel, iron, cobalt, chromium and manganese with a purity of 99.5 wt.% and a total content of impurities of N, P, S and the like controlled to be 0.5 wt.% or less are selected as raw materials, alloy powder is prepared by a nitrogen atomization method, powder with a particle size range of 25-55 μm and a good sphericity (see fig. 2) is used for atmospheric plasma spraying, a substrate is low carbon steel, the surface of the alloy powder is pretreated to remove a surface oxide film and dirt, and then sand blasting is performed, a high-entropy alloy coating is prepared by an atmospheric plasma spraying process in a performance test process, the thickness of the coating is 400-500 μm (for microstructure and test bonding strength) or 1mm (for test), the prepared alloy powder material and the coating are subjected to an organizational structure, a test of the electrical resistivity and a test of the bonding strength under the same conditions, and the surface area of the prepared alloy powder material and the coating is subjected to a test of the organizational structure, the test of the electrical resistivity and the electrical resistivity of the prepared alloy powder material is 358 mm (a test of a diffraction instrument, a surface area of a sample is 358 mm)²The microstructure was observed by a Zeiss field emission SEM electron microscope (GemininSEM 300), the resistivity was measured by a four-point probe method using a conductivity meter model ZEM-2, the sample size was 18 × 3 × 0.9.9 mm³(ii) a Coating bond strength test, according to test standards: ASTMC633-01, wherein the sample and the loading rod are 4032 aluminum alloy, the bonding material is high-temperature structural adhesive E-7, the tensile strength of the bonding material is 70MPa, the bonding material is kept for 3 hours under the curing condition of 110 ℃, and the bonding material is tested under the room temperature condition, and experimental equipment is vinpocetine QBD-100.