阅读说明：本技术 一种碳化铬金属陶瓷复合粉末、涂层及其制备方法 (Chromium carbide metal ceramic composite powder, coating and preparation method thereof ) 是由 李方义 杜际雨 李燕乐 鹿海洋 戚小霞 冉学举 张兴艺 于 2020-12-21 设计创作，主要内容包括：本发明属于金属陶瓷领域,涉及一种碳化铬金属陶瓷复合粉末、涂层及其制备方法,以质量分数计,粉末中各组分分别为Cr-3C-2：63.75-67.5％、Ni：17-18％、Cr：7.29-8.43％、Co：6.58-9.87％、Mo：0.63-0.95％。采用超音速喷涂系统喷涂上述复合粉末以制备碳化铬金属陶瓷复合涂层,该涂层具有良好致密性与结合强度。相比于传统的镍铬-碳化铬(Cr-3C-2-NiCr)涂层,该涂层在抗高温氧化、耐磨损等性能方面有了显著的改善,可应用于流化床燃烧器、喷嘴、锅炉部件、管道等部件的修复与强化。(The invention belongs to the field of metal ceramics, and relates to chromium carbide metal ceramic composite powder, a chromium carbide metal ceramic coating and a preparation method thereof 3 C 2 : 63.75-67.5%, Ni: 17-18%, Cr: 7.29-8.43%, Co: 6.58-9.87%, Mo: 0.63-0.95%. The composite powder is sprayed by a supersonic spraying system to prepare the chromium carbide metal ceramic composite coating, and the coating has good compactness and bonding strength. Compared with the traditional nickel chromium-chromium carbide (Cr) 3 C 2 -NiCr) coating, which is highly resistantThe performance aspects of warm oxidation, abrasion resistance and the like are obviously improved, and the method can be applied to the repair and reinforcement of parts such as fluidized bed combustors, nozzles, boiler parts, pipelines and the like.)

1. The chromium carbide metal ceramic composite powder is characterized by comprising the following raw materials in percentage by weight: cr (chromium) component₃C₂: 63.75-67.5%, Ni: 17-18%, Cr: 7.29-8.43%, Co: 6.58-9.87%, Mo: 0.63-0.95%, and the sum of the percentages of the components is 100%.

2. The chromium carbide metal ceramic composite coating is characterized by being prepared by spraying nickel-chromium carbide spherical powder and cobalt, chromium and molybdenum spherical powder serving as raw materials.

3. The chromium carbide cermet composite coating of claim 2, wherein the nickel chromium-chromium carbide spherical powder is comprised of 75% Cr₃C₂And 25% NiCr, with a particle size of 15-45 μm.

4. A chromium carbide cermet composite coating according to claim 2, characterised in that the spherical cobalt, chromium or molybdenum powder has a particle size of 15-45 μm.

5. The chromium carbide cermet composite coating of claim 2, wherein the coating has a thickness of 500-600 μm.

6. A preparation method of a chromium carbide metal ceramic composite coating is characterized by comprising the following steps:

uniformly mixing the nickel-chromium carbide spherical powder and the cobalt, chromium and molybdenum spherical powder, ball-milling, drying and sieving to obtain chromium carbide metal ceramic composite powder;

and (3) carrying out sand blasting treatment on the matrix, and spraying the chromium carbide metal ceramic composite powder by adopting a supersonic speed flame spraying system to obtain the chromium carbide metal ceramic composite powder.

7. The method for preparing the chromium carbide cermet composite coating according to claim 6, wherein the ball milling is performed by a wet ball milling method, preferably, the ball-to-material ratio is 5:1, or the solvent is ethanol, or the ball milling is performed for 1-2 hours.

8. The method for preparing the chromium carbide cermet composite coating according to claim 6, wherein the drying condition is 80-90 ℃ and the drying time is 10-12 hours;

or, the mixture is sieved by 320 meshes and 800 meshes.

9. The method for preparing the chromium carbide cermet composite coating according to claim 6, wherein the sand blasting is performed by high pressure gas sand blasting, preferably 30-50 mesh brown corundum, the pressure of the compressed gas is set to be 0.6-0.8MPa, the sand blasting gun is kept as perpendicular as possible to the surface of the substrate during the sand blasting, and the sand blasting distance is kept at 120-200 mm.

10. The method for preparing the chromium carbide cermet composite coating according to claim 6, wherein the specific conditions of the spraying are as follows: the flow rate of propane is 50-70m³The propane pressure is 0.6-0.8MPa, and the oxygen flow is 80-100m³H, oxygen pressure of 1.3-1.5MPa, hydrogen pressure of 0.3-0.5MPa, nitrogen pressure of 1.3MPa, compressed air flow rate of 150m³The compressed air pressure is 1.1-1.3MPa, the spraying distance is 180-220mm, and the spraying distance is 4-5 mm.

Technical Field

The invention relates to chromium carbide metal ceramic composite powder, a chromium carbide metal ceramic composite coating and a preparation method thereof, in particular to an oxidation-resistant, wear-resistant and erosion-resistant chromium carbide metal ceramic composite coating and a preparation method thereof.

Background

The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

Fluidized bed combustors, nozzles, boiler components, pipes, etc. are mainly used in the petrochemical, aerospace, power generation, metallurgical, etc. industries, and under high temperature conditions, these components suffer severe oxidation without proper surface coatings. In order to repair damaged components, to extend the service life of the components, surface coatings are prepared that are resistant to high temperature oxidation, which is beneficial in reducing the environmental impact of oxidation.

The chromium carbide metal ceramic composite coating is an ideal choice for repairing the surface of the member and has excellent high-temperature oxidation resistance, hot corrosion resistance and erosion resistance. Among them, currently, the most widely used is nickel chromium-chromium carbide (Cr)₃C₂-NiCr), which is formed from Cr₃C₂A hard ceramic phase and a NiCr metal binder phase. The thermal spraying technology is a method that a thermal source is utilized to heat a spraying material to a molten or semi-molten state, and the spraying material is sprayed onto the surface of a substrate at a certain speed to form a coating layer by continuous deposition. The chromium carbide metal ceramic composite coating prepared by the thermal spraying technology has the characteristics of good compactness, bonding strength, wear resistance, oxidation resistance and the like. Wherein, the high velocity oxygen fuel spraying (HVOF) has low carbide loss and high efficiency in preparing the chromium carbide metal ceramic composite coating, so the high velocity oxygen flame spraying (HVOF) has low carbide loss and high efficiencyThe spraying is a spraying method suitable for the chromium carbide metal ceramic composite coating. Conventional nickel chromium-chromium carbide (Cr)₃C₂-NiCr) coating has the oxidation resistance deteriorated in high-temperature oxidation environment above 800 ℃, but the oxidation resistance, hot corrosion resistance and high-temperature wear resistance of the coating still need to be improved.

Disclosure of Invention

In order to overcome the defects of the existing chromium carbide metal ceramic composite coating and improve the high-temperature oxidation performance of the existing chromium carbide metal ceramic composite coating, the invention provides chromium carbide metal ceramic composite powder, a chromium carbide metal ceramic composite coating and a preparation method of the chromium carbide metal ceramic composite coating. The oxidation resistance and wear resistance of the chromium carbide metal ceramic composite coating material are improved by adding Co and Mo elements into the coating so as to meet the use requirements of actual working conditions with higher requirements.

In order to achieve the technical purpose, the invention adopts the following technical scheme:

the invention provides a chromium carbide metal ceramic composite powder, which comprises the following raw materials in percentage by weight: cr (chromium) component₃C₂: 63.75-67.5%, Ni: 17-18%, Cr: 7.29-8.43%, Co: 6.58-9.87%, Mo: 0.63-0.95%, and the sum of the percentages of the components is 100%.

The prior research generally adopts chromium nickel-chromium carbide (Cr)₃C₂-NiCr) coating with certain elements to improve its performance, but due to the wide variety of elements, the diversity of combinations, and the uncertainty of the effect of different element combinations on the phases and phase compositions, no one has been found that can effectively increase the amount of nichrome-chromium carbide (Cr)₃C₂-NiCr) coating a new coating with high temperature oxidation resistance. To this end, the system of the present application analyzes the Gibbs free energy of formation of various oxide and spinel phases and performs calculationsThe calculation result is as follows: in the range of 700 ℃ and 900 ℃,(as shown in fig. 1). The above-mentioned gibbs free energy calculation results show that,Cr₂O₃has higher affinity with CoO to react to form CoCr₂O₄CoCr during oxidation of the coating₂O₄Compared with NiCr₂O₄Has higher priority and CoCr₂O₄The thermal stability of (A) is better. Based on the analysis and calculation results, the following experimental investigation is combined to find that: the addition of Co and Mo elements to conventional nickel chromium-chromium carbide (Cr)₃C₂NiCr) coating binder phase, and the influence of the binder phase on the oxidation resistance of the coating is researched by adjusting the components of different elements in the binder phase and designing different element ratios (as shown in Table 1). As shown in fig. 2 and 3, compared to conventional nickel chromium-chromium carbide (Cr)₃C₂-NiCr) coating, nickel chromium cobalt molybdenum-chromium carbide (Cr)₃C₂-NiCrCoMo) coating forms a denser oxide film in oxidation and has lower oxidation weight gain, thus having better oxidation resistance.

The invention provides a chromium carbide metal ceramic composite coating, which is prepared by spraying nickel-chromium carbide spherical powder and cobalt, chromium and molybdenum spherical powder serving as raw materials.

In order to further improve the high-temperature oxidation performance of the chromium carbide metal ceramic composite coating, the coating is based on the traditional nickel chromium-chromium carbide (Cr)₃C₂-NiCr) powder, the invention develops a multielement alloy binding phase modified nickel-chromium-cobalt-molybdenum-chromium carbide (Cr)₃C₂-NiCrCoMo) cermet composite powder and coating.

In a third aspect of the present invention, a preparation method of a chromium carbide metal ceramic composite coating is provided, which comprises:

uniformly mixing the nickel-chromium carbide spherical powder and the cobalt, chromium and molybdenum spherical powder, ball-milling, drying and sieving to obtain chromium carbide metal ceramic composite powder;

and (3) carrying out sand blasting treatment on the matrix, and spraying the chromium carbide metal ceramic composite powder by adopting a supersonic speed flame spraying system to obtain the chromium carbide metal ceramic composite powder.

The invention has the beneficial effects that:

(1) the invention adopts nickel chromiumThe chromium carbide powder is added with cobalt and molybdenum elements, so that a novel bonding phase composition is formed in the composite powder. Through high-temperature oxidation experimental tests, compared with the original nickel-chromium carbide coating, the novel multi-element alloy bonding phase modified nickel-chromium-cobalt-molybdenum-chromium carbide (Cr)₃C₂-NiCrCoMo) metal ceramic composite coating has better oxidation resistance. The above Cr₃C₂The NiCrCoMo coating forms an oxidation film of a composite component on the surface of the coating in an oxidation process, so that the oxidation rate is reduced and the oxidation resistance of the coating is improved. The addition of Co and Mo improves Cr₃C₂The matching between the oxide film and the coating of the NiCrCoMo coating improves the integrity of the oxide film, and meanwhile, the addition of the cobalt and the molybdenum leads spinel phases with high melting points and low ion diffusion coefficients to be formed in the oxide film, and the generation of spinel helps to improve the thermal stability of the oxide film.

(2) The multielement alloy binder phase modified nickel chromium cobalt molybdenum-chromium carbide (Cr) of the present invention based on design of gibbs free energy calculations and oxide film composition for various oxides₃C₂the-NiCrCoMo) metal ceramic composite coating is greatly improved in the aspects of oxidation resistance, high temperature wear resistance and the like, is reliable in preparation process, can be used in the fields of fluidized bed combustors, nozzles, boiler parts, pipelines and the like, and has high application value.

(3) The method is simple, convenient to operate, high in practicability and easy to popularize.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

FIG. 1 is a graph showing the results of Gibbs free energy calculations for spinel phase formation according to the present invention;

FIG. 2 is a graph of cyclic oxidation weight gain at different temperatures for coatings prepared according to example 1 of the present invention;

FIG. 3 shows the micro-morphology of the coating and the oxide film of the coating prepared in example 1 of the present invention oxidized for 200h at different temperatures.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The nickel chromium cobalt molybdenum-chromium carbide (Cr) of the invention₃C₂-NiCrCoMo) metal ceramic composite powder, wherein each component in the powder is Cr respectively according to mass fraction₃C₂：63.75-67.5％、Ni：17-18％、Cr：7.29-8.43％、Co：6.58-9.87％、Mo：0.63-0.95％。

The chromium carbide metal ceramic composite coating with the functions of oxidation resistance, wear resistance and erosion resistance is prepared by performing supersonic flame spraying on the composite powder with the formula, the thickness of the prepared coating is 100-600 mu m, the tensile bonding strength of the coating is not less than 55MPa, the density of the coating is good, the porosity of the coating is not more than 2.6 percent (image measurement method), and the Vickers hardness of the coating is not less than 900HV_0.3。

The preparation method of the oxidation-resistant, wear-resistant and erosion-resistant chromium carbide metal ceramic composite powder and the coating comprises the following steps:

1) selecting nickel chromium-chromium carbide (Cr) with grain size of 15-45 μm₃C₂-25% NiCr) spherical powder (composition: 75% Cr₃C₂25% NiCr) and spherical powder of cobalt, chromium and molybdenum (Co, Cr and Mo) with the grain diameter of 15-45 mu m, wherein the powder is weighed according to the following mixture ratio: cr (chromium) component₃C₂：63.75-67.5％、Ni：17-18％、Cr：7.29-8.43％、Co：6.58-9.87％、Mo: 0.63-0.95%. After the proportioning is finished, uniformly mixing the powder, placing the powder into a ball milling tank, adding grinding balls according to the ball-material ratio of 5:1, adding absolute ethyl alcohol to two thirds of the ball milling tank, sealing the ball milling tank, placing the ball milling tank into the ball milling machine, and milling for 1-2 hours, so that the homogenization of the composite powder is realized under the condition that the appearance of original powder particles is not damaged.

2) After the ball milling is finished, pouring the mixed slurry of the composite powder and the absolute ethyl alcohol in the ball milling tank into a stainless steel flat disc, uniformly spreading the mixed slurry, and then putting the flat disc into a vacuum drying oven for vacuum drying, wherein the drying temperature is set to 80 ℃, and the drying time is 12 hours. After the completion of drying, the composite powder was sieved using 320-mesh and 800-mesh sieves to remove large particles and broken particle pieces in the composite powder.

3) The surface of the sprayed base material is treated by using a high-pressure gas sand blasting method, brown corundum with 30-50 meshes is adopted in the sand blasting treatment process, the pressure intensity of compressed gas is set to be 0.6-0.8MPa, the sand blasting gun is kept perpendicular to the surface of the base body as far as possible in the sand blasting process, and the sand blasting distance is kept at 120-200 mm.

4) Spraying the composite powder prepared in the step 2) by using supersonic flame spraying, thereby preparing the chromium carbide metal ceramic composite coating with oxidation resistance, wear resistance and erosion resistance.

The invention is used for preparing nickel-chromium-cobalt-molybdenum-chromium carbide (Cr)₃C₂-NiCrCoMo) metal ceramic composite coating process adopts XM-5000 type supersonic flame spraying system, propane flow rate is 50-70m³The propane pressure is 0.6-0.8MPa, and the oxygen flow is 80-100m³H, oxygen pressure of 1.3-1.5MPa, hydrogen pressure of 0.3-0.5MPa, nitrogen pressure of 1.3MPa, compressed air flow rate of 150m³The compressed air pressure is 1.1-1.3MPa, the spraying distance is 180-220mm, and the spraying distance is 4-5 mm.

The high-pressure air sand blasting method adopted in the embodiment of the invention carries out sand blasting treatment on the surface of the matrix so as to remove dirt on the surface of the matrix and carry out roughening treatment. The sand blasting adopts 30-50 meshes of brown corundum, the pressure of the adopted compressed gas is 0.6-0.8MPa, the sand blasting gun is kept perpendicular to the surface of the substrate as much as possible in the sand blasting process, and the sand blasting distance is kept at 120-200 mm.

The embodiment of the invention adopts the nickel chromium-chromium carbide (Cr) with the grain diameter of 15-45 mu m₃C₂-25% NiCr) spherical powder (composition: 75% Cr₃C₂25% NiCr) and spherical powder of cobalt, chromium and molybdenum (Co, Cr and Mo) with the grain diameter of 15-45 mu m, wherein the powder is weighed according to the following mixture ratio: cr (chromium) component₃C₂: 63.75-67.5%, Ni: 17-18%, Cr: 7.29-8.43%, Co: 6.58-9.87%, Mo: 0.63-0.95%. After the proportioning is finished, uniformly mixing the powder, placing the powder into a ball milling tank, adding grinding balls according to the ball-material ratio of 5:1, adding absolute ethyl alcohol to two thirds of the ball milling tank, sealing the ball milling tank, placing the ball milling tank into the ball milling machine, and milling for 1-2 hours, so that the homogenization of the composite powder is realized under the condition that the appearance of original powder particles is not damaged. After the ball milling is finished, pouring the mixed slurry of the composite powder and the absolute ethyl alcohol in the ball milling tank into a stainless steel flat disc, uniformly spreading the mixed slurry, and then putting the flat disc into a vacuum drying oven for vacuum drying, wherein the drying temperature is set to 80 ℃, and the drying time is 12 hours. After the completion of drying, the composite powder was sieved using 320-mesh and 800-mesh sieves to remove large particles and broken particle pieces in the composite powder.

The present invention is described in further detail below with reference to specific examples, which are intended to be illustrative of the invention and not limiting.

Example 1

Adopts nickel chromium-chromium carbide (Cr) with the grain diameter of 15-45 mu m₃C₂-25% NiCr) spherical powder (composition: 75% Cr₃C₂25% NiCr) and spherical powder of cobalt, chromium and molybdenum (Co, Cr and Mo) with the grain diameter of 15-45 mu m, wherein the powder is weighed according to the following mixture ratio: cr (chromium) component₃C₂: 63.75%, Ni: 17%, Cr: 8.43%, Co: 9.87%, Mo: 0.95 percent. After the proportioning is finished, uniformly mixing the powder, putting the powder into a ball milling tank, adding grinding balls according to the ball material ratio of 5:1, adding absolute ethyl alcohol to two thirds of the ball milling tank, sealing the ball milling tank, putting the ball milling tank into the ball milling machine for ball milling for 1.5 hours, and putting the slurry into a vacuum drying oven for ball millingDrying treatment, wherein the drying temperature is set to 80 ℃ and the drying time is 12 hours. The surface of the FV520B stainless steel substrate is subjected to sand blasting by adopting the high-pressure air sand blasting method, and the specific process conditions are as follows: the brown corundum with 30-50 meshes is adopted, the pressure of the adopted compressed gas is 0.7MPa, the sand blasting gun is kept perpendicular to the surface of the base body as far as possible in the sand blasting process, and the sand blasting distance is kept at 150 mm.

The powder prepared above was sprayed using XM-5000 supersonic flame spray system with propane flow of 50m³H, propane pressure 0.7MPa, oxygen flow 80m³H, oxygen pressure of 1.5MPa, hydrogen pressure of 0.5MPa, nitrogen pressure of 1.3MPa, compressed air flow of 120m³The compressed air pressure is 1.3MPa, the spraying distance is 180mm, and the spraying distance is 4 mm.

Prepared nickel chromium cobalt molybdenum-chromium carbide (Cr)₃C₂-NiCrCoMo) cermet composite coating thickness about 600 μm, coating porosity of 1.83%, coating microhardness of 902.8HV_0.3. The tensile bond strength of the coating to the substrate was about 70 MPa.

After high-temperature oxidation at the temperature of 700 ℃ and 900 ℃ for 200 hours, a dense and uniform oxide film is formed on the surface of the coating, and the thickness of the oxide film is 5-15 mu m. Compared with the original nickel chromium-chromium carbide (Cr)₃C₂-25% NiCr) coating, nickel chromium cobalt molybdenum-chromium carbide (Cr)₃C₂-NiCrCoMo) cermet composite coating with reduced oxidative weight gain of 0.089mg/cm at 700 deg.C²And the temperature is reduced by 0.125mg/cm at 800 DEG C²And the temperature is reduced by 0.165mg/cm at 900 DEG C²Nickel chromium cobalt molybdenum-chromium carbide (Cr)₃C₂-NiCrCoMo) coating shows significantly reduced oxidation weight gain and better high temperature oxidation resistance, as shown in fig. 2 and 3.

Example 2

The preparation method of the nickel-chromium-cobalt-molybdenum-chromium carbide powder coating with different element ratios is the same as that of example 1.

TABLE 1

It should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and the present invention is not limited thereto, and although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications and equivalents can be made in the technical solutions described in the foregoing embodiments, or equivalents thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. Although the present invention has been described with reference to the specific embodiments, it should be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.