Boron-doped zirconium-chromium-nickel alloy coating and its preparation process

Abstract

The present invention provides a boron-doped zirconium-chromium-nickel alloy coating and its preparation process, relating to the technical field of alloy coatings. The boron-doped zirconium-chromium-nickel alloy coating comprises, by mass, the following components: B: 0.3% to 5%; Cr: 25% to 30%; Zr: 15% to 25%; and the remainder Ni; the sum of the mass percentages of the above components being 100%. The boron-doped zirconium-chromium-nickel alloy coating exhibits excellent high-temperature oxidation resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy coatings, and in particular to a boron-doped zirconium-chromium-nickel alloy coating and a preparation process thereof. Background Art

[0002] Zirconium-chromium-nickel alloys exhibit excellent high-temperature corrosion and wear resistance and are widely used in the coating of the hottest components of aircraft jet engines, ships, and industrial gas turbines. However, while existing zirconium-chromium-nickel alloys exhibit excellent high-temperature mechanical properties, their high-temperature oxidation resistance remains to be improved. Therefore, developing a coating with high-temperature oxidation resistance is of great significance. Summary of the Invention

[0003] The purpose of the present invention includes providing a boron-doped zirconium-chromium-nickel alloy coating and a preparation process thereof, so as to solve the technical problem that the existing coating has poor high-temperature oxidation resistance.

[0004] In order to solve the above problems, the present invention provides a boron-doped zirconium-chromium-nickel alloy coating, wherein the alloy coating comprises the following components by mass percentage:

[0005] B: 0.3% to 5%;

[0006] Cr: 25% to 30%;

[0007] Zr: 15% to 25%;

[0008] The rest is Ni;

[0009] The sum of the mass percentages of the above components is 100%.

[0010] Optionally, the mass percentage of B is preferably 1% to 4.5%; more preferably 2% to 3.5%.

[0011] The present invention also provides a preparation process for a boron-doped zirconium-chromium-nickel alloy coating, which is used to prepare the above-mentioned boron-doped zirconium-chromium-nickel alloy coating. The preparation process comprises the following steps:

[0012] Mixed ball milling: according to the mass percentage: B powder 0.3% to 5%, Cr powder 25% to 30%, Zr powder 15% to 25%, and the rest Ni powder, and the sum of the mass percentages of the above components is 100%, weigh and put into a ball mill and ball mill for 3 to 10 hours to obtain raw material powder;

[0013] Substrate pretreatment: remove oxides and oil stains on the surface of the substrate to be deposited, and preheat the substrate to obtain the deposited substrate;

[0014] Laser cladding: Dry raw material powder is used as the cladding raw material, and laser cladding is performed on the surface to be clad of the cladding substrate to obtain a boron-doped zirconium-chromium-nickel alloy coating.

[0015] Optionally, the laser cladding step includes: the cladding substrate is located in the cladding chamber of the laser cladding equipment, the raw material powder is loaded into the powder feeder of the laser cladding equipment, the cladding chamber is sealed and filled with inert gas; the surface to be clad of the cladding substrate is laser clad using a shielding gas synchronous powder feeding method, and the laser cladding parameters are: laser power 1~3kW, powder feeding amount 10~15g / min, defocus amount 15~22mm, cladding speed 250~300mm / min, and shielding gas flow rate 0.3~0.7ml / min.

[0016] Optionally, the laser cladding step further includes a post-heat treatment step: when the boron-doped zirconium-chromium-nickel alloy coating obtained by the laser cladding step is cooled to 200-300°C, the boron-doped zirconium-chromium-nickel alloy coating is heat treated at 950-1050°C using laser cladding equipment, and the laser heat treatment parameters are: laser power 1-3kW, defocus amount 20-25mm, laser scanning speed 250-300mm / min; after the heat treatment is completed, the boron-doped zirconium-chromium-nickel alloy coating is naturally cooled to room temperature.

[0017] Optionally, in the mixed ball milling step, the weighed B powder, Cr powder, Zr powder and Ni powder are placed in a ball milling jar, and anhydrous ethanol is added to the ball milling jar, and the weight of the anhydrous ethanol is 1% to 2% of the total weight of the B powder, Cr powder, Zr powder and Ni powder, and then the ball milling jar is placed in a ball mill for ball milling.

[0018] Optionally, before the ball mill jar is loaded into the ball mill, the ball mill jar is evacuated and an inert gas is introduced.

[0019] Optionally, after the ball milling is completed, the raw material powder is cooled to room temperature, taken out of the ball mill jar and placed in a vacuum box and heated at 20-40° C. for 10-30 minutes to obtain dry raw material powder for the laser cladding step.

[0020] Optionally, the dried raw material powder is passed through a 150-180 mesh sieve to remove powder lumps.

[0021] Optionally, in the substrate pretreatment step, anhydrous ethanol is used to clean the surface to be welded to remove oxides and oil stains on the surface to be welded, and then the substrate is preheated to 50-150° C. to obtain a welded substrate.

[0022] The boron-doped zirconium-chromium-nickel alloy coating provided by the present invention has a relatively high content of Ni and Cr. Both are homogeneous and hard with good corrosion resistance and wear resistance. Zr, which has a lower content, has better high temperature resistance and can enhance the high temperature corrosion resistance of the alloy coating, thereby making the alloy coating have better wear resistance and corrosion resistance under high temperature conditions. B is added to the Zr-Cr-Ni matrix. Under high temperature conditions, B has strong reducing properties. The B on the surface of the alloy coating can react with oxygen in the environment or capture oxygen atoms from other oxides to generate molten B2O3, thereby forming a molten state on the surface of the alloy coating. The barrier layer is uniformly distributed in the molten state, and external oxygen atoms cannot enter the alloy coating within the barrier layer due to the blocking effect of the barrier layer. The barrier layer can effectively hinder the oxidation of the metal components in the alloy coating inside the barrier layer by oxygen atoms, so that the alloy coating has strong oxidation resistance under high-temperature conditions, thereby ensuring the high-temperature performance of each metal component in the alloy coating, so that the alloy coating can maintain its better wear resistance and corrosion resistance under high-temperature conditions; wherein, the addition of B in the above-mentioned mass ratio range can not only ensure its oxidation resistance, but also have little effect on reducing the high-temperature strength of the alloy coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0024] Figure 1 This is a photograph of the fracture morphology of a boron-doped zirconium-chromium-nickel alloy coating prepared according to the preparation process of Example 1 of the present invention. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] This embodiment provides a boron-doped zirconium-chromium-nickel alloy coating, which includes the following components by mass percentage: B: 0.3% to 5%; Cr: 25% to 30%; Zr: 15% to 25%; and the remainder is Ni; wherein the sum of the mass percentages of the above components is 100%.

[0027] In the boron-doped zirconium-chromium-nickel alloy coating provided in this embodiment, Ni and Cr content is relatively high, both of which are homogeneous and hard with good corrosion resistance and wear resistance, and Zr, which has the second largest content, has better high temperature resistance and can enhance the high temperature corrosion resistance of the alloy coating, thereby making the alloy coating have better wear resistance and corrosion resistance under high temperature conditions; B is added to the Zr-Cr-Ni matrix, and under high temperature conditions, B has strong reducing properties. The B on the surface of the alloy coating can react with oxygen in the environment or capture oxygen atoms from other oxides to generate molten B2O3, thereby forming A barrier layer is formed in a molten state and is evenly distributed. External oxygen atoms cannot enter the alloy coating within the barrier layer due to the blocking effect of the barrier layer. The barrier layer can effectively hinder the oxidation of the metal components in the alloy coating inside the barrier layer by oxygen atoms, so that the alloy coating has strong oxidation resistance under high temperature conditions, thereby ensuring the high temperature performance of each metal component in the alloy coating, so that the alloy coating can maintain its better wear resistance and corrosion resistance under high temperature conditions; wherein, the addition of B in the above-mentioned mass ratio range can not only ensure its oxidation resistance, but also have little effect on reducing the high temperature strength of the alloy coating.

[0028] In addition, since Zr, C, and Ni elements are relatively abundant and inexpensive in the earth's crust, and the amount of B added is relatively small, an alloy coating with excellent high-temperature oxidation resistance can be obtained at a lower cost; in addition, the alloy coating of this embodiment contains only four components, Zr, C, Ni, and B, and operations such as purchase and mixing are relatively simple, thereby improving the convenience of preparing the alloy coating and further reducing the preparation cost of the alloy coating accordingly.

[0029] Optionally, in this embodiment, the mass percentage of B is preferably 1% to 4.5%; further preferably, 2% to 3.5%. When the B content is low, the B content on the surface of the alloy coating is also low. Under high-temperature conditions, the continuity of the barrier layer formed by B oxidation to molten B2O3 is poor, and the barrier effect on ambient oxygen atoms is reduced. Accordingly, the high-temperature oxidation resistance of the alloy coating cannot be significantly improved. When the B content is high, the high-temperature strength of the alloy coating is significantly reduced, resulting in reduced wear resistance and corrosion resistance of the alloy coating. Therefore, selecting the above mass percentage of B can form a barrier layer with good continuity and small thickness on the surface of the alloy coating under high-temperature conditions, which can not only provide good oxidation resistance, but also ensure that the alloy coating maintains its strong high-temperature wear resistance and corrosion resistance. Specifically, the mass percentage of B can be 0.3%, 0.8%, 1.3%, 1.8%, 2.3%, 2.8%, 3.3%, 3.8%, 4.3%, 4.8%, 5.0%, and any mass percentage between the two value points.

[0030] Optionally, the mass percentage of Cr is preferably 26% to 29%; further preferably, 27% to 28%; specifically, the mass percentage of Cr can be 25.0%, 25.5%, 26.0%, 26.5%, 27.0%, 27.5%, 28.0%, 28.5%, 29.0%, 29.5%, 30.0%, and any mass percentage between the two value points.

[0031] Specifically, the mass percentage of Zr is preferably 17% to 23%; further preferably 19% to 21%; specifically, the mass percentage of Zr can be 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, and any mass percentage between the two value points.

[0032] This embodiment also provides a preparation process of a boron-doped zirconium-chromium-nickel alloy coating, which is used to prepare the above-mentioned boron-doped zirconium-chromium-nickel alloy coating. The preparation process includes the following steps:

[0033] Mixed ball milling: According to the mass percentage: B powder 0.3% to 5%, Cr powder 25% to 30%, Zr powder 15% to 25%, and the rest Ni powder, and the sum of the mass percentages of the above components is 100%, weigh them and put them into a ball mill for ball milling for 3 to 10 hours to obtain raw material powder. Weigh B powder, Cr powder, Zr powder and Ni powder according to the designed mass percentage of each component, and put the weighed powders into the ball mill for ball milling for 3 to 10 hours, so that the four powders are fully mixed, so that B powder can be evenly attached to the surface of Cr powder, Zr powder and Ni powder, to ensure the uniform distribution of B on the surface of the alloy coating subsequently prepared, thereby ensuring that under high temperature conditions, the distribution of B to generate molten B2O3 is more uniform, and a continuous molten barrier layer can be formed with a smaller thickness, thereby ensuring that the alloy coating can maintain its high temperature wear resistance and corrosion resistance on the basis of having better high temperature oxidation resistance. In addition to affecting the mixing uniformity of the components, the ball milling time also affects the average particle size of each component. Specifically, the longer the ball milling time, the smaller the average particle size of each component; the shorter the ball milling time, the larger the average particle size of each component. The ball milling time can be determined according to actual needs. Optionally, the ball milling time is preferably 5-8 hours; more preferably 6-7 hours; specifically, the ball milling time can be 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, and any time in between.

[0034] Substrate pretreatment: Remove oxides and oil stains from the surface of the substrate to be clad, and preheat the substrate to obtain a clad substrate. First, the surface of the substrate to be clad is cleaned to remove oxides and oil stains on the surface, so as to improve the cladding bonding strength between the cladding material and the substrate surface to be clad in the subsequent laser cladding step, reduce the occurrence of coating warping and shedding, and thus ensure the coating's protective effect on the substrate; after the cleaning treatment is completed, the substrate is preheated to a certain temperature, so as to improve the cladding bonding strength between the cladding material and the substrate in the subsequent laser cladding step, and reduce the occurrence of cracking of the clad alloy coating due to the low temperature of the cladding substrate.

[0035] Laser cladding: Using dry raw material powder as the cladding material, laser cladding is performed on the surface of the cladding substrate to obtain a boron-doped zirconium-chromium-nickel alloy coating. The dryness of the raw material powder obtained by mixed ball milling is ensured, and the dry raw material powder is then laser clad onto the surface of the cladding substrate to form a boron-doped zirconium-chromium-nickel alloy coating on the surface of the cladding substrate. The alloy coating obtained using the laser cladding process has low dilution, thin thickness, and strong bonding with the substrate. This method can save a significant amount of coating raw material costs while meeting the required coating surface properties.

[0036] It can be seen that the preparation process provided in this embodiment can produce an alloy coating with strong bonding with the substrate, low dilution and small thickness. While meeting the surface property requirements of the coating, a large amount of coating raw material cost can be saved; at the same time, the preparation process has requirements for the selection of each component of the deposited raw material and the mass percentage, so that the obtained alloy coating has better high-temperature wear resistance, corrosion resistance and oxidation resistance.

[0037] Specifically, during the mixing and ball milling step, the average particle size of each component is no greater than 250 μm, and the purity of each component is no less than 90%. Using B powder, Cr powder, Zr powder, and Ni powder with an average particle size of 250 μm or less for ball milling can efficiently complete the mixing and obtain raw material powders of appropriate particle size, thereby improving ball milling efficiency and shortening ball milling time.

[0038] Specifically, in the mixed ball milling step of this embodiment, the weighed B powder, Cr powder, Zr powder, and Ni powder are placed in a ball milling jar. Anhydrous ethanol is then added to the jar, with the weight of the anhydrous ethanol being 1% to 2% of the total weight of the B powder, Cr powder, Zr powder, and Ni powder. The jar is then placed in a ball mill for ball milling. The B powder, Cr powder, Zr powder, and Ni powder are weighed according to mass percentage and then placed in the jar with a certain amount of anhydrous ethanol for wet milling. This improves ball milling efficiency, shortens milling time, and produces a raw material powder with higher particle size uniformity and more stable performance. After the ball milling is completed, the ball mill can be turned off, the jar removed and opened to allow the anhydrous ethanol to evaporate, resulting in a dry raw material powder. Among them, the weight of anhydrous ethanol is preferably 1.3% to 1.7% of the total weight of B powder, Cr powder, Zr powder and Ni powder; further preferably 1.5%; specifically, the weight of anhydrous ethanol can be 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0% of the total weight of B powder, Cr powder, Zr powder and Ni powder, and any mass percentage between the two value points.

[0039] Preferably, after the ball milling is completed, after the raw material powder has cooled to room temperature, the raw material powder can be taken out from the ball mill and placed in a vacuum box and heated at 20-40°C for 10-30 minutes to obtain a dry raw material powder for the laser cladding step. After the wet milling is completed, the raw material powder that has cooled to room temperature can be taken out and placed in a vacuum box for drying to ensure that the anhydrous ethanol doped therein can be completely volatilized, thereby improving the dryness and purity of the raw material powder, and correspondingly ensuring the performance of the coating made from the raw material powder. Among them, a vacuum environment is maintained during the drying process of the raw material powder in a vacuum box to reduce the oxidation of the raw material powder during the drying process, thereby ensuring the purity of the raw material powder. Specifically, the raw material powder can be placed in a crucible for drying, and the crucible is preferably vacuum-dried at a certain temperature to ensure the cleanliness of the crucible itself. Optionally, the drying temperature is preferably 25-35°C; more preferably 28-32°C; specifically, the drying temperature can be 20°C, 23°C, 25°C, 28°C, 30°C, 32°C, 35°C, 38°C, 40°C, and any temperature value between the two values. The drying time is preferably 15-25 minutes; more preferably 18-22 minutes; specifically, the drying time can be 10 minutes, 13 minutes, 15 minutes, 18 minutes, 20 minutes, 22 minutes, 25 minutes, 28 minutes, 30 minutes, and any time between the two values.

[0040] Specifically, after drying, the dried raw material powder is passed through a 150-180 mesh sieve to remove powder lumps to ensure the uniformity of the raw material powder and reduce the occurrence of powder lumps that cannot be melted and cause the coating to have lumps, thereby ensuring the uniformity of the coating.

[0041] Optionally, the ball mill can be evacuated and filled with an inert gas before loading it into the ball mill. A vacuum- and gas-filled ball mill is selected. After loading the B powder, Cr powder, Zr powder, Ni powder, and anhydrous ethanol into the ball mill, the ball mill is evacuated and filled with an inert gas to create an inert atmosphere. The ball mill is then loaded into the ball mill for ball milling. This reduces the risk of oxidation of the B powder, Cr powder, Zr powder, and Ni powder by oxygen during the ball milling process, which could affect the purity of the raw powders and thus ensure the performance of the raw powders and the alloy coating. Specifically, inexpensive Ar can be used as the inert gas. Optionally, weighing and loading the B powder, Cr powder, Zr powder, and Ni powder should be performed as quickly as possible to minimize oxidation and moisture absorption by the B powder, Cr powder, Zr powder, and Ni powder. Specifically, Ar with a purity of approximately 99.99% can be used as the inert gas.

[0042] Specifically, in this embodiment, in the substrate pretreatment step, anhydrous ethanol is used to clean the surface to be welded to remove oxides and oil stains on the surface to be welded, and then the substrate is preheated to 50-150°C to obtain a welded substrate. Using anhydrous ethanol to clean the surface to be welded of the substrate is convenient and low-cost; after cleaning, the substrate is heated to 50-150°C. While preheating the substrate, the ethanol on the surface of the substrate can also be volatilized to further ensure the cleanliness of the surface to be welded, so that it can better bond with the coating. Among them, the substrate preheating temperature is preferably 70-130°C; more preferably 90-110°C; specifically, the substrate preheating temperature can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, and any temperature between the two value points.

[0043] In this embodiment, the laser cladding step may include: positioning a cladding substrate within a cladding chamber of a laser cladding device, loading raw material powder into a powder feeder of the laser cladding device, sealing the cladding chamber, and filling the cladding chamber with an inert gas; laser cladding the surface of the cladding substrate to be clad using a shielding gas synchronous powder feeding method, wherein the laser cladding parameters are: laser power of 1-3 kW, powder feeding rate of 10-15 g / min, defocusing distance of 15-22 mm, cladding speed of 250-300 mm / min, and shielding gas flow rate of 0.3-0.7 ml / min. The shielding gas is an inert gas, specifically Ar with a purity of approximately 99.99%. During the laser cladding process, the shielding gas can simultaneously feed the powder while maintaining an inert atmosphere in the cladding chamber. The raw material powder is clad onto the substrate surface under the aforementioned laser cladding parameters, and the resulting cladding layer, i.e., the alloy coating, has high density, strong bonding to the substrate, high uniformity, low thickness, low dilution, and excellent high-temperature wear resistance, corrosion resistance, and oxidation resistance.

[0044] In the laser cladding step, the laser power is preferably 1.4-2.6 kW, more preferably 1.8-2.2 kW, and specifically, the laser power can be 1.0 kW, 1.4 kW, 1.8 kW, 2.2 kW, 2.6 kW, 3.0 kW, and any power between the two values. The powder feed rate is preferably 11-14 g / min, more preferably 12-13 g / min, and specifically, the powder feed rate can be 10 g / min, 10.5 g / min, 11 g / min, 11.5 g / min, 12 g / min, 12.5 g / min, 13 g / min, 13.5 g / min, 14 g / min, 14.5 g / min, and any value between the two values. The defocusing distance is preferably 17-20 mm, more preferably 18-19 mm. Specifically, the defocusing distance can be 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, and any distance between the two value points. The cladding speed is preferably 260-290 mm / min, more preferably 270-280 mm / min. Specifically, the cladding speed can be 250 mm / min, 255 mm / min, 260 mm / min, 265 mm / min, 270 mm / min, 275 mm / min, 280 mm / min, 285 mm / min, 290 mm / min, 295 mm / min, 300 mm / min, and any speed between the two value points. The protective gas flow rate is preferably 0.4-0.6 ml / min; more preferably 0.5 ml / min; specifically, the protective gas flow rate can be 0.30 ml / min, 0.35 ml / min, 0.40 ml / min, 0.45 ml / min, 0.50 ml / min, 0.55 ml / min, 0.60 ml / min, 0.65 ml / min, 0.70 ml / min, and any flow rate between the two value points.

[0045] Optionally, in this embodiment, the laser cladding step further includes a post-heat treatment step: when the boron-doped zirconium-chromium-nickel alloy coating obtained by the laser cladding step cools to 200-300°C, the boron-doped zirconium-chromium-nickel alloy coating is subjected to a heat treatment at 950-1050°C using a laser cladding device. The laser heat treatment parameters are: laser power of 1-3 kW, defocus of 20-25 mm, and laser scanning speed of 250-300 mm / min. After the heat treatment, the boron-doped zirconium-chromium-nickel alloy coating is naturally cooled to room temperature. After the laser cladding step, when the alloy coating cools to 200-300°C, the laser cladding device is continued to perform a post-heat treatment at 950-1050°C on the alloy coating to increase the density of the alloy coating and reduce its cracking tendency, thereby further improving the bonding strength between the coating and the substrate and ensuring the protective effect of the coating on the substrate.

[0046] In the post-treatment step, the cooling temperature is preferably 220-280°C, more preferably 240-260°C. Specifically, the cooling temperature can be 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, and any temperature in between. The heat treatment temperature is preferably 980-1020°C, more preferably 1000°C. Specifically, the heat treatment temperature can be 950°C, 960°C, 980°C, 1000°C, 1020°C, 1040°C, 1050°C, and any temperature in between. The laser scanning speed is preferably 260-290 mm / min; more preferably 270-280 mm / min; specifically, the laser scanning speed can be 250 mm / min, 255 mm / min, 260 mm / min, 265 mm / min, 270 mm / min, 275 mm / min, 280 mm / min, 285 mm / min, 290 mm / min, 295 mm / min, 300 mm / min, and any speed between the two values. The laser power and defocus can be set according to the specific heat treatment temperature.

[0047] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0048] Example 1

[0049] Step 1, weighing B powder, Cr powder, Zr powder, and Ni powder with an average particle size of 250 μm and a purity of not less than 99.9% according to mass percentages of 0.3%, 30%, 25%, and 44.7%;

[0050] Step 2: The B powder, Cr powder, Zr powder, and Ni powder weighed in step 1 are placed in a ball mill, and anhydrous ethanol with a weight of 1.5% of the total weight of the B powder, Cr powder, Zr powder, and Ni powder is added to the ball mill. The ball mill is evacuated and Ar with a purity of 99.99% is introduced. The ball mill is placed in a ball mill and ball milled for 7 hours to obtain a raw powder. The machine is stopped and the raw powder is naturally cooled to room temperature.

[0051] Step 3: Take out the raw material powder in step 2 and quickly put it into a white corundum crucible that has been vacuum-dried at 100°C and cooled to room temperature, and place it in a vacuum box and heat it at 30°C for 30 minutes to remove anhydrous ethanol to obtain a dry raw material powder;

[0052] Step 4: Pass the dried raw material powder obtained in step 3 through a 180-mesh sieve to remove powder lumps;

[0053] Step 5: Clean the surface of the substrate (Q235 steel) to be deposited with anhydrous ethanol to remove oxides and oil stains on the surface of the substrate; preheat the substrate to 100° C.

[0054] Step 6: Load the raw material powder obtained in step 4 into the powder feeder of the laser cladding equipment, seal the cladding chamber and fill it with protective gas, and use the protective gas synchronous powder feeding method to laser clad the surface to be clad of the cladding substrate (the powder flow is in the middle, surrounded by 4 laser beams of the same power and evenly distributed). The laser cladding parameters are: laser power 3kW, powder feeding rate 15g / min, defocusing amount 15mm, cladding speed 250mm / min, and protective gas flow rate 0.5ml / min; wherein, the protective gas is Ar with a purity of 99.99%;

[0055] In step 7, when the alloy coating obtained in step 6 is cooled to 200°C, the alloy coating is heat treated at about 950°C using laser cladding equipment. The laser heat treatment parameters are: laser power 0.5kW, defocus amount 22mm, laser scanning speed 250mm / min; after the heat treatment, the alloy coating is naturally cooled to room temperature to finally obtain a boron-doped zirconium-chromium-nickel alloy coating.

[0056] Figure 1 This is a fracture morphology of the boron-doped zirconium-chromium-nickel alloy coating prepared according to Example 1 of the present invention, with a display accuracy of 10 μm. Figure 1 It can be seen that the grain density of each component in the alloy coating is high and the average grain size is relatively consistent.

[0057] Specifically, the boron-doped zirconium-chromium-nickel alloy coating prepared in Example 1 of the present invention and the existing zirconium-chromium-nickel alloy without boron doping were placed under high-temperature working conditions of 800°C for high-temperature oxidation resistance tests. The oxidation weight gain of the two alloy materials is shown in Table 1. Among them, the oxidation weight gain of the boron-doped zirconium-chromium-nickel alloy coating prepared in Example 1 of the present invention is reduced by nearly half compared with the oxidation weight gain of the zirconium-chromium-nickel alloy without boron doping.

[0058] Table 1

[0059] Boron-free zirconium-chromium-nickel alloy Boron-doped zirconium-chromium-nickel alloy <![CDATA[Oxidation weight gain (mg / h·mm 2 )]]> 21.2 10.3

[0060] Example 2

[0061] Step 1, weighing B powder, Cr powder, Zr powder, and Ni powder with an average particle size of 150 μm and a purity of not less than 99.5% according to mass percentages of 5%, 25%, 25%, and 45%;

[0062] Step 2: The B powder, Cr powder, Zr powder, and Ni powder weighed in step 1 are placed in a ball mill, and anhydrous ethanol with a weight of 1.5% of the total weight of the B powder, Cr powder, Zr powder, and Ni powder is added to the ball mill. The ball mill is evacuated and Ar with a purity of 99.99% is introduced. The ball mill is placed in a ball mill and ball milled for 5 hours to obtain a raw powder. The machine is shut down and the raw powder is naturally cooled to room temperature.

[0063] Step 3: Take out the raw material powder in step 2 and quickly put it into a white corundum crucible that has been vacuum-dried at 100°C and cooled to room temperature, and place it in a vacuum box and heat it at 30°C for 20 minutes to remove anhydrous ethanol to obtain a dry raw material powder;

[0064] Step 4: Pass the dried raw material powder obtained in step 3 through a 150-mesh sieve to remove powder lumps;

[0065] Step 5: Clean the surface of the substrate (Q235 steel) to be deposited with anhydrous ethanol to remove oxides and oil stains on the surface of the substrate; preheat the substrate to 100° C.

[0066] Step 6: Load the raw material powder obtained in step 4 into the powder feeder of the laser cladding equipment, seal the cladding chamber and fill it with protective gas, and use the protective gas synchronous powder feeding method to laser clad the surface to be clad of the cladding substrate (the powder flow is in the middle, surrounded by 4 laser beams of the same power and evenly distributed). The laser cladding parameters are: laser power 1kW, powder feeding rate 10g / min, defocusing amount 15mm, cladding speed 300mm / min, and protective gas flow rate 0.5ml / min; wherein, the protective gas is Ar with a purity of 99.99%;

[0067] In step 7, when the alloy coating obtained in step 6 is cooled to 300°C, the alloy coating is heat treated at about 1050°C using laser cladding equipment. The laser heat treatment parameters are: laser power 0.5kW, defocus amount 22mm, laser scanning speed 300mm / min; after the heat treatment, the alloy coating is naturally cooled to room temperature to finally obtain a boron-doped zirconium-chromium-nickel alloy coating.

[0068] Specifically, the boron-doped zirconium-chromium-nickel alloy coating prepared in Example 2 of the present invention and the existing zirconium-chromium-nickel alloy without boron doping were placed under high-temperature working conditions of 800°C for high-temperature oxidation resistance tests. The oxidation weight gain of the two alloy materials is shown in Table 2. Among them, the oxidation weight gain of the boron-doped zirconium-chromium-nickel alloy coating prepared in Example 2 of the present invention is less than half of the oxidation weight gain of the zirconium-chromium-nickel alloy without boron doping.

[0069] Table 2

[0070] Boron-free zirconium-chromium-nickel alloy Boron-doped zirconium-chromium-nickel alloy <![CDATA[Oxidation weight gain (mg / h·mm 2 )]]> 21.2 8.3

[0071] Example 3

[0072] Step 1, weighing B powder, Cr powder, Zr powder, and Ni powder with an average particle size of 50 μm and a purity of not less than 99.5% according to mass percentages of 2%, 30%, 15%, and 53%;

[0073] Step 2: The B powder, Cr powder, Zr powder, and Ni powder weighed in step 1 are placed in a ball mill, and anhydrous ethanol with a weight of 1.5% of the total weight of the B powder, Cr powder, Zr powder, and Ni powder is added to the ball mill. The ball mill is evacuated and Ar with a purity of 99.99% is introduced. The ball mill is placed in a ball mill and ball milled for 10 hours to obtain a raw powder. The machine is shut down and the raw powder is naturally cooled to room temperature.

[0074] Step 3: Take out the raw material powder in step 2 and quickly put it into a white corundum crucible that has been vacuum-dried at 100°C and cooled to room temperature, and place it in a vacuum box and heat it at 30°C for 30 minutes to remove anhydrous ethanol to obtain a dry raw material powder;

[0075] Step 4: Pass the dried raw material powder obtained in step 3 through a 160-mesh sieve to remove powder lumps;

[0076] Step 5: Clean the surface of the substrate (Q235 steel) to be deposited with anhydrous ethanol to remove oxides and oil stains on the surface of the substrate; preheat the substrate to 100° C.

[0077] Step 6: Load the raw material powder obtained in step 4 into the powder feeder of the laser cladding equipment, seal the cladding chamber and fill it with protective gas, and use the protective gas synchronous powder feeding method to laser clad the surface to be clad of the cladding substrate (the powder flow is in the middle, surrounded by 4 laser beams of the same power and evenly distributed). The laser cladding parameters are: laser power 2kW, powder feeding rate 15g / min, defocusing amount 15mm, cladding speed 300mm / min, and protective gas flow rate 0.5ml / min; wherein, the protective gas is Ar with a purity of 99.99%;

[0078] In step 7, when the alloy coating obtained in step 6 is cooled to 250°C, the alloy coating is heat treated at about 1000°C using laser cladding equipment. The laser heat treatment parameters are: laser power 0.5kW, defocus amount 22mm, laser scanning speed 300mm / min; after the heat treatment, the alloy coating is naturally cooled to room temperature to finally obtain a boron-doped zirconium-chromium-nickel alloy coating.

[0079] Specifically, the boron-doped zirconium-chromium-nickel alloy coating prepared in Example 3 of the present invention and the existing zirconium-chromium-nickel alloy without boron doping were placed under high-temperature working conditions of 800°C for high-temperature oxidation resistance tests. The oxidation weight gain of the two alloy materials is shown in Table 3. Among them, the oxidation weight gain of the boron-doped zirconium-chromium-nickel alloy coating prepared in Example 3 of the present invention is reduced by nearly two-thirds compared with the oxidation weight gain of the zirconium-chromium-nickel alloy without boron doping.

[0080] Table 3

[0081] Boron-free zirconium-chromium-nickel alloy Boron-doped zirconium-chromium-nickel alloy <![CDATA[Oxidation weight gain (mg / h·mm 2 )]]> 21.2 7.1

[0082] Example 4

[0083] Step 1, weighing B powder, Cr powder, Zr powder, and Ni powder with an average particle size of 250 μm and a purity of not less than 99.9% according to mass percentages of 1%, 26%, 20%, and 53%;

[0084] Step 2: The B powder, Cr powder, Zr powder, and Ni powder weighed in step 1 are placed in a ball mill, and anhydrous ethanol with a weight of 1.5% of the total weight of the B powder, Cr powder, Zr powder, and Ni powder is added to the ball mill. The ball mill is evacuated and Ar with a purity of 99.99% is introduced. The ball mill is placed in a ball mill and ball milled for 5 hours to obtain a raw powder. The machine is shut down and the raw powder is naturally cooled to room temperature.

[0085] Step 3: Take out the raw material powder in step 2 and quickly put it into a white corundum crucible that has been vacuum-dried at 100°C and cooled to room temperature, and place it in a vacuum box and heat it at 30°C for 25 minutes to remove anhydrous ethanol to obtain a dry raw material powder;

[0086] Step 4: Pass the dried raw material powder obtained in step 3 through a 180-mesh sieve to remove powder lumps;

[0087] Step 5: Clean the surface of the substrate (Q235 steel) to be deposited with anhydrous ethanol to remove oxides and oil stains on the surface of the substrate; preheat the substrate to 100° C.

[0088] Step 6: Load the raw material powder obtained in step 4 into the powder feeder of the laser cladding equipment, seal the cladding chamber and fill it with protective gas, and use the protective gas synchronous powder feeding method to laser clad the surface to be clad of the cladding substrate (the powder flow is in the middle, surrounded by 4 laser beams of the same power and evenly distributed). The laser cladding parameters are: laser power 1.5kW, powder feeding rate 12g / min, defocusing amount 15mm, cladding speed 280mm / min, and protective gas flow rate 0.5ml / min; wherein, the protective gas is Ar with a purity of 99.99%;

[0089] In step 7, when the alloy coating obtained in step 6 is cooled to 250°C, the alloy coating is heat treated at about 950°C using laser cladding equipment. The laser heat treatment parameters are: laser power 0.5kW, defocus amount 22mm, laser scanning speed 280mm / min; after the heat treatment, the alloy coating is naturally cooled to room temperature to finally obtain a boron-doped zirconium-chromium-nickel alloy coating.

[0090] Specifically, the boron-doped zirconium-chromium-nickel alloy coating prepared in Example 4 of the present invention and the existing zirconium-chromium-nickel alloy without boron doping were placed under high-temperature conditions of 800°C for high-temperature oxidation resistance tests. The oxidation weight gain of the two alloy materials is shown in Table 4. Among them, the oxidation weight gain of the boron-doped zirconium-chromium-nickel alloy coating prepared in Example 4 of the present invention is reduced by nearly half compared with the oxidation weight gain of the zirconium-chromium-nickel alloy without boron doping.

[0091] Table 4

[0092] Boron-free zirconium-chromium-nickel alloy Boron-doped zirconium-chromium-nickel alloy <![CDATA[Oxidation weight gain (mg / h·mm 2 )]]> 21.2 10.4

[0093] It can be seen that under the same high-temperature working conditions, the oxidation weight gain of the boron-doped zirconium-chromium-nickel alloy coating provided by the present invention is much lower than the oxidation weight gain of the existing zirconium-chromium-nickel alloy without boron doping, and accordingly has better high-temperature oxidation resistance; at the same time, the cost of the boron-doped zirconium-chromium-nickel alloy coating provided by the present invention is only about 10% higher than that of the existing zirconium-chromium-nickel alloy without boron doping, and has a better cost-effectiveness advantage.

[0094] Finally, it should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0095] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A process for preparing a boron-doped zirconium-chromium-nickel alloy coating, characterized in that: For preparing a boron-doped zirconium-chromium-nickel alloy coating, the preparation process comprises the following steps: Mixed ball milling: according to the mass percentage: B powder 2.3% to 5%, Cr powder 26% to 29%, Zr powder 17% to 23%, and the rest is Ni powder, and the sum of the mass percentages of the above components is 100%, weigh and put into a ball mill and ball mill for 3 to 10 hours to obtain raw material powder; Substrate pretreatment: remove oxides and oil stains on the surface of the substrate to be deposited, and preheat the substrate to obtain the deposited substrate; Laser cladding: using dry raw material powder as cladding raw material, laser cladding is performed on the surface to be clad of the cladding substrate to obtain a boron-doped zirconium-chromium-nickel alloy coating; Post-heat treatment step: when the boron-doped zirconium-chromium-nickel alloy coating obtained by the laser cladding step is cooled to 200-300°C, the boron-doped zirconium-chromium-nickel alloy coating is heat treated at 980-1020°C using laser cladding equipment, and the laser heat treatment parameters are: laser power 1-3kW, defocus amount 20-25mm, laser scanning speed 250-300mm / min; after the heat treatment is completed, the boron-doped zirconium-chromium-nickel alloy coating is naturally cooled to room temperature.

2. The preparation process according to claim 1, characterized in that The laser cladding step includes: placing the cladding substrate in a cladding chamber of a laser cladding device, loading raw material powder into a powder feeder of the laser cladding device, sealing the cladding chamber and filling it with inert gas; laser cladding the surface to be clad of the cladding substrate using a shielding gas synchronous powder feeding method, and the laser cladding parameters are: laser power 1-3kW, powder feeding amount 10-15g / min, defocus amount 15-22mm, cladding speed 250-300mm / min, and shielding gas flow rate 0.3-0.7ml / min.

3. The preparation process according to claim 1, characterized in that In the mixed ball milling step, the weighed B powder, Cr powder, Zr powder and Ni powder are placed in a ball mill jar, and anhydrous ethanol is added to the ball mill jar, and the weight of the anhydrous ethanol is 1% to 2% of the total weight of the B powder, Cr powder, Zr powder and Ni powder. Then, the ball mill jar is placed in a ball mill for ball milling.

4. The preparation process according to claim 3, characterized in that Before the ball mill jar is loaded into the ball mill, the ball mill jar is evacuated and an inert gas is introduced into the jar.

5. The preparation process according to claim 3, characterized in that: After the ball milling is completed, the raw material powder is cooled to room temperature, taken out from the ball mill and placed in a vacuum box and heated at 20-40° C. for 10-30 minutes to obtain a dry raw material powder for the laser cladding step.

6. The preparation process according to claim 5, characterized in that: The dried raw material powder is passed through a 150-180 mesh sieve to remove powder lumps.

7. The preparation process according to claim 1, characterized in that In the substrate pretreatment step, anhydrous ethanol is used to clean the surface to be welded to remove oxides and oil stains on the surface to be welded, and then the substrate is preheated to 50-150° C. to obtain a welded substrate.

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