A wear-resistant and high-temperature-resistant nickel-chromium alloy material and a preparation method thereof

Abstract

The application relates to the field of nickel-chromium alloy materials, in particular to a wear-resistant and high-temperature-resistant nickel-chromium alloy material and a preparation method thereof. The wear-resistant and high-temperature-resistant nickel-chromium alloy material is prepared from raw materials with the following mass fractions by powder metallurgy: 70wt%-91wt% of nickel-chromium alloy powder, 6wt%-25wt% of titanium dioxide modified tungsten carbide particles, 2wt%-3wt% of Al2O3 powder and 1wt%-2wt% of acidized carbon nanotubes. The tungsten carbide particles are modified by being coated with titanium dioxide. The repulsion between the positive charges of the titanium dioxide improves the dispersibility of the tungsten carbide. The titanium dioxide is beneficial to the grain refinement of the tungsten carbide, improves the hardness and strength, and the chemical and metallurgical combination between the tungsten carbide and the nickel-chromium alloy is complementary between the materials. The application not only improves the use temperature, but also enhances the tensile property and wear resistance. The prepared nickel-chromium alloy material has the characteristics of high hardness, corrosion resistance, wear resistance and high-temperature resistance, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nickel-chromium alloy materials, in particular to a wear-resistant and high-temperature-resistant nickel-chromium alloy material and a preparation method thereof. BACKGROUND

[0002] Nickel-chromium alloy is a widely used alloy material, which has the characteristics of high working temperature, high hardness, good corrosion resistance, etc., and is commonly used in the fields of electrothermal alloy, precision resistance alloy, super-oxidizing medium, petrochemical industry, oral cavity repair, etc. With the rapid development of emerging industries and high-tech fields, the requirements for material performance, service life, cost and other aspects have been improved, and the stability of the material under extreme conditions is also particularly important. For example, under high temperature and high pressure environments, the material cannot be damaged or even scrapped due to local damage to the surface of the material. However, the existing nickel-chromium alloy generally has the shortcomings of insufficient wear resistance and high-temperature resistance. The common ways to improve the wear resistance and high-temperature resistance of nickel-chromium alloy include: (1) adjusting the types and proportions of alloy elements; (2) using advanced heat treatment processes to improve the performance and stability of the alloy; (3) surface treatment of the material, such as using ceramic coating technology to enhance the wear resistance of the alloy.

[0003] In order to solve the above technical problems, the present application provides a wear-resistant and high-temperature-resistant nickel-chromium alloy material and a preparation method thereof. Tungsten carbide is a refractory metal carbide with extremely high hardness, high melting temperature and chemical inertness, which has a significant effect on improving the wear resistance and high-temperature resistance of the alloy material. Tungsten carbide and nickel-chromium alloy have chemical and metallurgical combination, and the advantages of the materials are complementary. It can not only meet the demand for high hardness and corrosion resistance of the material in industrial production, but also meet the requirements of wear resistance and high-temperature resistance, which is beneficial to the extension of the service life and the expansion of the application prospect of the commonly used alloy material. However, tungsten carbide is difficult to disperse and easy to agglomerate, so it is crucial to make tungsten carbide have good dispersibility. SUMMARY

[0004] The present application utilizes the characteristics of high hardness and high melting temperature of tungsten carbide, introduces tungsten carbide into nickel-chromium alloy, and uses powder metallurgy to enhance the nickel-chromium alloy material with tungsten carbide particles. However, due to the poor dispersibility of tungsten carbide particles, it is easy to agglomerate. In order to improve its dispersibility, the titanium dioxide is coated on the surface of the tungsten carbide particles to introduce positive charges on the surface of the tungsten carbide particles, so as to enhance the dispersibility. That is, first, a nickel-chromium alloy material is prepared by solid solution quenching treatment, then the nickel-chromium alloy material is crushed and ball milled to obtain a nickel-chromium alloy powder, and then the wear-resistant and high-temperature-resistant nickel-chromium alloy material is prepared by powder metallurgy after mixing the nickel-chromium alloy powder with the modified tungsten carbide particles and titanium dioxide.

[0005] The wear-resistant and high-temperature-resistant nickel-chromium alloy material is prepared by powder metallurgy from raw materials with the following mass fractions: 70wt%-91wt% of nickel-chromium alloy powder, 6wt%-25wt% of titanium dioxide modified tungsten carbide particles, 2wt%-3wt% of Al2O3 powder, and 1wt%-2wt% of acidified carbon nanotubes.

[0006] The nickel-chromium alloy powder is composed of the following components with the following mass fractions: 55%-72% of nickel, 20%-33% of chromium, 6%-9% of iron, 0.4%-1.5% of boron, 0.05%-0.2% of silicon, 0.3%-0.5% of molybdenum, 0.04%-0.08% of carbon, 0.5%-1% of zirconium, and the rest being unavoidable impurities.

[0007] The preparation method of the wear-resistant and high-temperature-resistant nickel-chromium alloy material comprises the following steps:

[0008] Step 1: mixing nickel and chromium according to the ratio and then putting them into a vacuum melting furnace to prepare an alloy melt;

[0009] Step 2: high-temperature melting of the remaining alloy raw materials under argon protection, mixing with the alloy melt prepared in step 1, and then performing solid solution and quenching treatment to obtain a nickel-chromium alloy.

[0010] Step 3: crushing and sieving the nickel-chromium alloy obtained in step 2, and then ball milling in a ball mill to obtain a nickel-chromium alloy powder.

[0011] Step 4: drying the titanium dioxide modified tungsten carbide particles, Al2O3 powder, and acidified carbon nanotubes in an oven, and then mixing them with the ball-milled nickel-chromium alloy powder to obtain a mixed powder.

[0012] Step 5: placing the mixed powder in a mold and applying pressure to obtain a wear-resistant and high-temperature-resistant nickel-chromium alloy material after compression molding and high-temperature sintering.

[0013] Preferably, the temperature for preparing the alloy melt in step 1 is 3200°C-3800°C, the vacuum degree is 0.09MPa, and the time is 1-4h.

[0014] Preferably, the high-temperature melting temperature in step 2 is 3200°C-3800°C, the time is 1-2h, the mixing refining temperature is 1100°C-1600°C, the time is 1-3h, the solid solution temperature is 950°C-1100°C, the holding time is 15min-90min, the quenching temperature is 1050°C-1200°C, the quenching time is 5-10min, and the solid solution and quenching treatment are performed in air.

[0015] Preferably, the particle size of the nickel-chromium alloy powder obtained by ball milling in step 3 is 100-800mesh.

[0016] Preferably, the preparation of the titanium dioxide modified tungsten carbide particles in step 4 comprises the following steps:

[0017] S1, washing and drying the tungsten carbide particles to ensure that the surface is free of impurities and moisture;

[0018] S2, dissolving tetrabutyl titanate in anhydrous ethanol as a titanium dioxide precursor solution;

[0019] S3, mixing the tungsten carbide particles with the titanium dioxide precursor solution, stirring uniformly with a stirrer, maintaining stirring and adding deionized water to hydrolyze tetrabutyl titanate to form titanium dioxide, heating and holding, and then naturally cooling to room temperature to obtain a TiO2-WC mixture;

[0020] S4, filtering the TiO2-WC mixture to obtain insoluble matter, and then drying in an oven to remove residual anhydrous ethanol and water to obtain a dried TiO2-WC mixture;

[0021] S5, placing the dried TiO2-WC mixture in a tube furnace for heat treatment to form a uniform coating of titanium dioxide on the surface of the tungsten carbide particles to obtain titanium dioxide modified tungsten carbide particles.

[0022] Preferably, the particle size of the titanium dioxide modified tungsten carbide particles in step 4 is 20-100 μm, the particle size of the Al2O3 powder is 75 μm, and the particle size of the acidified carbon nanotubes is 10-20 nm with a length of 30 nm; the drying is carried out at 80°C for 7-10 h.

[0023] Preferably, the pressure in step 5 is 300-500 MPa, the high-temperature sintering is carried out in an argon atmosphere at a temperature of 900°C-1200°C for 1-3 h.

[0024] Preferably, the washing in S1 is ultrasonic oscillation cleaning with acetone and deionized water for 10-30 min, and drying in an oven at 70°C for 30-60 min; the volume ratio of tetrabutyl titanate to anhydrous ethanol in S2 is 1:(1.5-2.5); the proportion of tungsten carbide particles to tetrabutyl titanate in S3 is (1-1.5 g) / mL, the stirring speed is 50-100 rpm, the stirring time is 20-60 min, the volume ratio of deionized water to tetrabutyl titanate is (0.8-1.2):1, and the preheating temperature is 60°C-90°C with a holding time of 1 h; the drying in S4 is carried out at 80°C for 30-60 min; and the heat treatment in S5 is carried out under nitrogen protection at a heat treatment temperature of 500-800°C with a heating rate of 5°C / min and a holding time of 30 min-2 h.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] In the process of melting nickel-chromium alloy raw materials, different amounts of Fe, B, Si, Mo, C, and Zr are added. The addition of these elements helps to improve the performance of nickel-chromium alloys. Mo can improve the high-temperature strength and corrosion resistance of the alloy. Si can improve the oxidation resistance and mechanical properties of the alloy. Fe affects the mechanical properties and heat treatment performance of the alloy. The addition of Si can increase hardness and strength, improve high-temperature stability, and improve wear resistance. Zr has excellent corrosion resistance and can maintain good mechanical properties at high temperatures, helping to reduce the grain size of the alloy.

[0027] Tungsten carbide has a high melting point and thermal stability, which can increase the thermal stability of alloy materials in high-temperature environments. By adding tungsten carbide particles to nickel-chromium alloys, the high-temperature performance of the material can be improved, and the heat resistance of the material can be improved. Tungsten carbide has extremely high hardness, which can significantly improve the hardness and strength of the alloy. The hardness of tungsten carbide makes it have excellent wear resistance, and adding tungsten carbide particles to nickel-chromium alloys can improve the wear resistance of the material, making it more suitable for high-friction and high-wear environments. Tungsten and molybdenum both have good corrosion resistance, and adding these two elements to nickel-chromium alloys can improve the stability of the alloy in corrosive environments and extend the service life of the material. Introducing tungsten carbide particles with extremely high hardness, high melting temperature, and chemical inertness into nickel-chromium alloys can help to strengthen the performance and service life of the material. To avoid the shortcomings of tungsten carbide, such as difficulty in dispersion and easy agglomeration, the surface of tungsten carbide is coated with a layer of titanium dioxide. Titanium dioxide usually has a positive charge, which can introduce an electric charge on the surface of tungsten carbide. The electrostatic repulsion between charges improves the dispersibility of titanium dioxide-modified tungsten carbide particles. The presence of titanium dioxide in the system also helps to refine the grain size of tungsten carbide, which is beneficial to improving hardness, density, and tensile strength. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Figure 1 is a schematic diagram of a three-body wear test device for wear resistance testing;

[0029] Figure 2 Figure 2 is a stress-strain curve diagram for determining yield strength by graphical method;

[0030] Figure 3 Figure 3 is a maximum force (F m ) diagram for measuring tensile strength by graphical method;

[0031] Figure 4 Figure 4 is a yield strength diagram of test samples at different temperatures;

[0032] Figure 5 Figure 5 is a tensile strength diagram of test samples at different temperatures.

[0033] wherein, Figure 1 1 is a spoon wheel, 2 is a hopper, 3 is a linear bearing, 4 is a weight and lever arm, 5 is a pressure sensor, 6 is a displacement sensor, 7 is a sample, 8 is a rotating wheel, 9 is a flow meter, and a is water. DETAILED DESCRIPTION

[0034] Example 1: A wear-resistant and high-temperature-resistant nickel-chromium alloy material is prepared by powder metallurgy from raw materials with the following mass fractions: nickel-chromium alloy powder 70wt%, titanium dioxide modified tungsten carbide 25wt%, Al2O3 powder 3wt%, and acidified carbon nanotubes 2wt%.

[0035] The nickel-chromium alloy powder is composed of the following mass fractions of components: nickel 68%, chromium 22%, iron 7%, boron 1.2%, silicon 0.15%, molybdenum 0.4%, carbon 0.08%, zirconium 0.8%, and the rest is unavoidable impurities.

[0036] A preparation method of a wear-resistant and high-temperature-resistant nickel-chromium alloy material, comprising the following steps:

[0037] Step 1: After mixing nickel and chromium according to the ratio, the alloy melt is prepared by putting it into a vacuum melting furnace, the temperature is 3600℃, the vacuum degree is 0.09MPa, and the time is 3h;

[0038] Step 2: Under the protection of argon, the remaining alloy raw materials are high-temperature melted at 3600℃ for 2h, and the alloy melt prepared in step 1 is added, mixed and refined at 1500℃ for 2h, then solid solution and quenching treatment are carried out, the solid solution temperature is 1000℃, the holding time is 50min, the quenching temperature is 1100℃, the quenching time is 5min, and the nickel-chromium alloy is obtained by casting;

[0039] Step 3: The nickel-chromium alloy obtained in step 2 is crushed and sieved, and then ball milled in a ball mill to obtain a nickel-chromium alloy powder, the particle size of the nickel-chromium alloy powder obtained by ball milling is 700 mesh;

[0040] Step 4: First, prepare titanium dioxide modified tungsten carbide particles, including the following steps:

[0041] S1: The tungsten carbide particles are sequentially cleaned with acetone and deionized water by ultrasonic oscillation for 30min, and then dried in an oven at 70℃ for 60min to ensure that the surface is free of impurities and moisture;

[0042] S2: Tetrabutyl titanate is dissolved in anhydrous ethanol as a titanium dioxide precursor solution, and the volume ratio of tetrabutyl titanate to anhydrous ethanol is 1:2;

[0043] S3, tungsten carbide particles are mixed with titanium dioxide precursor solution. The ratio of tungsten carbide particles to tetrabutyl titanate is 1.5 g / mL. The mixture is stirred at 80 rpm for 40 min until homogeneous. Stirring is maintained and deionized water is added to hydrolyze tetrabutyl titanate to form titanium dioxide. The volume ratio of deionized water to tetrabutyl titanate is 1:1. The mixture is heated to 70℃ and kept at that temperature for 1 h, and then naturally cooled to room temperature to obtain TiO2-WC mixture.

[0044] S4, filter the TiO2-WC mixture, and dry the insoluble matter in an oven at 80°C for 60 min to remove residual anhydrous ethanol and water, and obtain a dried TiO2-WC mixture;

[0045] S5. The dried TiO2-WC mixture was placed in a tube furnace and heat-treated under nitrogen protection at a temperature of 700℃, a heating rate of 5℃ / min, and a holding time of 2h. This process resulted in a uniform coating of titanium dioxide on the surface of the tungsten carbide particles, yielding titanium dioxide-modified tungsten carbide particles.

[0046] Titanium dioxide modified tungsten carbide particles, Al2O3 powder, and acidified carbon nanotubes were taken in proportion, dried in an oven at 80℃ for 8 hours to remove moisture, and then mixed with ball-milled nickel-chromium alloy powder to obtain a mixed powder. The particle size of the titanium dioxide modified tungsten carbide particles was 40μm, the particle size of the Al2O3 powder was 75μm, and the particle size of the acidified carbon nanotubes was 15nm and the length was 30nm.

[0047] Step 5: Place the mixed powder in a mold and apply a pressure of 350 MPa. After pressing and molding, sinter at 1000℃ for 3 hours under an argon atmosphere to obtain a wear-resistant and high-temperature resistant nickel-chromium alloy material.

[0048] Example 2: A wear-resistant and high-temperature resistant nickel-chromium alloy material, made by powder metallurgy from the following raw materials in the indicated mass fractions: 80wt% nickel-chromium alloy powder, 15wt% titanium dioxide-modified tungsten carbide, 3wt% Al2O3 powder, and 2wt% acidified carbon nanotubes;

[0049] The nickel-chromium alloy powder is composed of the following components by mass fraction: 68% nickel, 22% chromium, 7% iron, 1.2% boron, 0.15% silicon, 0.4% molybdenum, 0.08% carbon, 0.8% zirconium, with the remainder being unavoidable impurities.

[0050] A method for preparing a wear-resistant and high-temperature resistant nickel-chromium alloy material includes the following steps:

[0051] Step 1: Nickel and chromium are mixed in proportion and then put into a vacuum melting furnace to prepare an alloy melt. The temperature is 3600℃, the vacuum degree is 0.09MPa, and the time is 3h.

[0052] Step 2, under the protection of argon, the remaining alloy raw material is high-temperature smelted at 3600℃ for 2h, and is added into the alloy melt prepared in step 1, after 2h of mixing refining at 1500℃, solid solution and quenching treatment are carried out, the solid solution temperature is 1000℃, the holding time is 50min, the quenching temperature is 1100℃, the quenching time is 5min, and nickel-chromium alloy is poured to obtain a nickel-chromium alloy;

[0053] Step 3, the nickel-chromium alloy obtained in step 2 is crushed and sieved, and then is ball milled in a ball mill to obtain a nickel-chromium alloy powder, the particle size of the nickel-chromium alloy powder obtained by ball milling is 700 mesh;

[0054] Step 4, first, titanium dioxide modified tungsten carbide particles are prepared, including the following steps:

[0055] S1, the tungsten carbide particles are sequentially cleaned by ultrasonic oscillation with acetone and deionized water for 30min, and are dried in an oven at 70℃ for 60min to ensure that the surface is free of impurities and moisture;

[0056] S2, tetrabutyl titanate is dissolved in anhydrous ethanol as a titanium dioxide precursor solution, and the volume ratio of tetrabutyl titanate to anhydrous ethanol is 1:2;

[0057] S3, the tungsten carbide particles are mixed with the titanium dioxide precursor solution, the proportion of tungsten carbide particles to tetrabutyl titanate is 1.5g / mL, after stirring at 80rpm for 40min until uniform, stirring is maintained and deionized water is added to hydrolyze tetrabutyl titanate to form titanium dioxide, the volume ratio of deionized water to tetrabutyl titanate is 1:1, after heating to 70℃, it is kept for 1h, and then naturally cooled to room temperature to obtain a TiO2-WC mixture;

[0058] S4, the TiO2-WC mixture is filtered to obtain insoluble substances, which are dried in an oven at 80℃ for 60min to remove residual anhydrous ethanol and water, and a dried TiO2-WC mixture is obtained;

[0059] S5, the dried TiO2-WC mixture is placed in a tube furnace and heat treated under nitrogen protection, the heat treatment temperature is 700℃, the heating rate is 5℃ / min, and the holding time is 2h. The titanium dioxide forms a uniform coating on the surface of the tungsten carbide particles to obtain titanium dioxide modified tungsten carbide particles.

[0060] The titanium dioxide modified tungsten carbide particles, Al2O3 powder and acidified carbon nanotubes are taken in proportion, dried in an 80℃ oven for 8h to remove moisture, and then mixed with the ball-milled nickel-chromium alloy powder to obtain a mixed powder, wherein the particle size of the titanium dioxide modified tungsten carbide particles is 40μm, the particle size of the Al2O3 powder is 75μm, and the particle size of the acidified carbon nanotubes is 15nm and the length is 30nm.

[0061] Step 5, the mixed powder is placed in a mold and pressed into a shape under a pressure of 350 MPa, and then sintered at 1000℃ for 3h under an argon atmosphere to obtain the wear-resistant and high-temperature-resistant nickel-chromium alloy material.

[0062] Example 3: A wear-resistant and high-temperature-resistant nickel-chromium alloy material is prepared by powder metallurgy from raw materials with the following mass fractions: nickel-chromium alloy powder 91wt%, titanium dioxide modified tungsten carbide 6wt%, Al2O3 powder 2wt%, and acidified carbon nanotubes 1wt%.

[0063] The nickel-chromium alloy powder is composed of the following mass fractions of components: nickel 68%, chromium 22%, iron 7%, boron 1.2%, silicon 0.15%, molybdenum 0.4%, carbon 0.08%, zirconium 0.8%, and the rest being unavoidable impurities.

[0064] A method for preparing a wear-resistant and high-temperature-resistant nickel-chromium alloy material, comprising the following steps:

[0065] Step 1, mix nickel and chromium according to the ratio, and then put them into a vacuum melting furnace to prepare an alloy melt, with a temperature of 3600℃, a vacuum degree of 0.09MPa, and a time of 3h;

[0066] Step 2, high-temperature melt the remaining alloy raw materials at 3600℃ for 2h under argon protection, and add the alloy melt prepared in step 1, mix and refine at 1500℃ for 2h, then perform solid solution and quenching treatment, with a solid solution temperature of 1000℃, a holding time of 50min, a quenching temperature of 1100℃, and a quenching time of 5min, and then cast to obtain a nickel-chromium alloy;

[0067] Step 3, crush and sieve the nickel-chromium alloy obtained in step 2, and then ball mill in a ball mill to obtain a nickel-chromium alloy powder, with a particle size of 700 mesh;

[0068] Step 4, first prepare titanium dioxide modified tungsten carbide particles, comprising the following steps:

[0069] S1, ultrasonically clean the tungsten carbide particles with acetone and deionized water for 30min, and then dry them in an oven at 70℃ for 60min to ensure that the surface is free of impurities and moisture;

[0070] S2, dissolve tetrabutyl titanate in anhydrous ethanol as a titanium dioxide precursor solution, with a volume ratio of tetrabutyl titanate to anhydrous ethanol of 1:2;

[0071] S3, mixing tungsten carbide particles with titanium dioxide precursor solution, the ratio of tungsten carbide particles to tetrabutyl titanate is 1.5 g / mL, stirring with a stirrer at 80 rpm for 40 min until uniform, then maintaining stirring and adding deionized water to hydrolyze tetrabutyl titanate to form titanium dioxide, the volume ratio of deionized water to tetrabutyl titanate is 1:1, heating to 70℃ and maintaining for 1 h, then naturally cooling to room temperature to obtain a TiO2-WC mixture;

[0072] S4, filtering the TiO2-WC mixture, drying the insoluble matter in an oven at 80℃ for 60 min to remove residual anhydrous ethanol and water, and obtaining a dried TiO2-WC mixture;

[0073] S5, placing the dried TiO2-WC mixture in a tube furnace and heat treating under nitrogen protection, the heat treatment temperature is 700℃, the heating rate is 5℃ / min, and the holding time is 2 h. The titanium dioxide forms a uniform coating on the surface of the tungsten carbide particles to obtain titanium dioxide modified tungsten carbide particles.

[0074] The titanium dioxide modified tungsten carbide particles, Al2O3 powder, and acidified carbon nanotubes are taken in proportion, dried at 80℃ for 8 h in an oven to remove water, and then mixed with the ball-milled nickel-chromium alloy powder in sequence to obtain a mixed powder, wherein the particle size of the titanium dioxide modified tungsten carbide particles is 40 μm, the particle size of the Al2O3 powder is 75 μm, and the particle size of the acidified carbon nanotubes is 15 nm and the length is 30 nm.

[0075] Step 5, placing the mixed powder in a mold and applying a pressure of 350 MPa, sintering at 1000℃ for 3 h under an argon atmosphere to obtain a wear-resistant and high-temperature-resistant nickel-chromium alloy material.

[0076] Comparative Example 1: based on Example 1, the difference is that no titanium dioxide modified tungsten carbide is added to enhance the nickel-chromium alloy material, and the remaining steps are the same as Example 1.

[0077] Comparative Example 2: based on Example 1, the difference is that the tungsten carbide particles are not modified, and the tungsten carbide particles are directly added to the nickel-chromium alloy powder for metallurgy, and the remaining steps are the same as Example 1.

[0078] Experimental Example

[0079] I. Wear resistance test (GB / T 34501-2017):

[0080] 1. Sample preparation:

[0081] The sample size is 50 mm x 20 mm, and it is first ultrasonically cleaned in acetone for 10 min before being placed into the test device, and the mass of the sample is measured using a precision balance with an accuracy of 0.1 mg before the test;

[0082] 2. Fixing of the specimen:

[0083] The specimen is clamped in the fixed position of the test rig. If necessary, the reference of the specimen should be checked and adjusted so that there is one contact plane in the width direction of the rotating wheel;

[0084] 3. Operating conditions:

[0085] The load is 130 N, the rotating speed is 1 m / s, the abrasive flow rate through the contact surface is 150 g / min, and the test time is 20 min;

[0086] 4. Start of the test:

[0087] Before starting the motor, move the specimen away from the rotating wheel; start the motor and flow in the abrasive. When the motor speed and the abrasive flow rate are stable, lower the specimen so that it is in contact with the rotating wheel and start the test; if an instrument test system is used, the data acquisition system should be started before the specimen is brought into contact with the rotating wheel;

[0088] 5. End or stop of the test:

[0089] When the specified test time is reached, the motor should be turned off and the abrasive flow should be stopped; if an instrument test system is used, the data acquisition should be stopped immediately after the motor and the abrasive flow are turned off;

[0090] The specimen is removed and cleaned before being reweighed; the specimen is visually observed to check whether the shape of the wear scar is flat; if the shape is not flat enough, the reference of the test rig and the shape of the rotating wheel should be checked and the test should be repeated;

[0091] 6. Number of repeated tests:

[0092] Each material should be tested at least twice under the same conditions.

[0093] II. Yield strength (GB / T 23370-2009):

[0094] 1. Determination by graphical method:

[0095] A pre-load is applied and the stress-strain curve is determined (F Figure 2 ), a parallel line BA to OC is drawn on the stress-strain curve drawn so that OB is equal to the given residual strain, and the intersection point Q has a vertical coordinate F c value of F cq , which represents the load corresponding to the yield point. It is sometimes difficult to determine the direction of the OC line from the curve graph, in which case the OC line can be drawn according to the equivalent value of the Young's modulus;

[0096] 2. Calculation of the yield strength R cq :

[0097] R cq = F cq / S o

[0098] R cq — yield strength in Newton per square millimeter (N / mm 2 );

[0099] F cq — load at yield point in Newton (N);

[0100] S o — minimum original cross-sectional area in square millimeter (mm 2 ).

[0101] Three, tensile strength:

[0102] The tensile strength is determined by graphical method.

[0103] For the samples showing obvious yield (discontinuous yield) phenomenon, the maximum force after the yield stage is read from the recorded force-extension or force-displacement curve; for the samples showing no obvious yield (continuous yield) phenomenon, the maximum force during the experiment is read from the recorded force-extension or force-displacement curve (F Figure 3 ). The maximum force is divided by the original cross-sectional area (S o ) of the sample to obtain the tensile strength.

[0104] Four, high temperature tensile test (GB / T 4338-1995):

[0105] According to the test methods of test two and three, the sample is heated to the specified temperature during the test using a heating device. The resolution of the temperature measuring instrument is 1℃, and the error is ±2℃.

[0106] When the original gauge length of the sample is equal to 50mm, one thermocouple is bound at each end; when it is greater than 50mm, one thermocouple is bound at each end and in the middle. The measuring end of the thermocouple has good thermal contact with the surface of the sample and avoids direct thermal radiation. After the sample is loaded into the furnace, it is generally heated to the specified test temperature within 1h, and the temperature is avoided to exceed the upper limit of the specified temperature. The sample can start the test only after it is kept at the specified test temperature for at least 10min. During the temperature keeping and the test until before the sample is broken, the temperature deviation should be within the specified range.

[0107] According to test examples one, two and three, the samples obtained in examples 1, 2 and 3 and comparative examples 1 and 2 are tested at room temperature, and the test results are shown in table 1:

[0108] Table 1 Test results of different examples at room temperature

[0109]

[0110] Table 1 shows the test results of various examples and comparative examples, indicating that the addition of titanium dioxide-modified tungsten carbide is beneficial to improving the tensile properties of nickel-chromium alloy materials. The yield strength and tensile strength of samples with added titanium dioxide-modified tungsten carbide and those with added tungsten carbide particles are superior to those without tungsten carbide. Simultaneously, the wear rate is significantly reduced, indicating improved wear resistance. The high-temperature resistance and high hardness of tungsten carbide clearly enhance the performance of nickel-chromium alloys. A comparison between the examples and Comparative Example 1 clearly shows that titanium dioxide-modified tungsten carbide helps improve the wear resistance and mechanical properties of nickel-chromium alloy materials. This is mainly because coating the surface of tungsten carbide particles with titanium dioxide introduces positive charges, and the repulsive force between charges improves particle dispersion, avoiding performance degradation caused by tungsten carbide particle agglomeration. In addition, the presence of titanium dioxide has the effect of refining the carbide grain size, which is beneficial to improving its hardness, density, and tensile strength. Furthermore, comparisons between different examples show that the mixing ratio of tungsten carbide and nickel-chromium alloy has a significant impact on the tensile properties and wear resistance of the material.

[0111] The yield strength of the samples was tested at room temperature, 300℃, 600℃, 900℃, and 1200℃ respectively. Figure 4 (as shown) and tensile strength (as shown) Figure 5 As shown in the figure, both tensile strength and yield strength exhibit a trend of first increasing and then decreasing with increasing temperature. The tensile properties of the samples without tungsten carbide modification and without tungsten carbide reinforcement show more significant changes in the high-temperature region, indicating that carbon dioxide-modified tungsten carbide has a significant enhancing effect on the performance of nickel-chromium alloy materials. The high hardness of tungsten carbide and the refining effect of titanium dioxide on tungsten carbide particles improve the strength of the material, and the high melting point of tungsten carbide also increases the service temperature of the material, thus improving its high-temperature resistance.

[0112] The embodiments described above are some, but not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. Therefore, other specific embodiments of the present invention obtained by those skilled in the art based on the inspiration of this technical solution without inventive effort should fall within the protection scope of the present invention.

Claims

1. A wear-resistant and high-temperature resistant nickel-chromium alloy material, characterized in that, The wear-resistant and high-temperature resistant nickel-chromium alloy material is made from the following raw materials by powder metallurgy: 70wt%~91wt% nickel-chromium alloy powder, 6wt%~25wt% titanium dioxide modified tungsten carbide particles, 2wt%~3wt% Al2O3 powder, and 1wt%~2wt% acidified carbon nanotubes; The nickel-chromium alloy powder is composed of the following components by mass fraction: nickel 55%~72%, chromium 20%~33%, iron 6%~9%, boron 0.4%~1.5%, silicon 0.05%~0.2%, molybdenum 0.3%~0.5%, carbon 0.04%~0.08%, zirconium 0.5%~1%, with the remainder being unavoidable impurities; The preparation method of the wear-resistant and high-temperature resistant nickel-chromium alloy material includes the following steps: Step 1: Mix nickel and chromium in the specified proportions and then put them into a vacuum melting furnace to prepare an alloy melt; Step 2: Under argon protection, the remaining alloy raw materials in the nickel-chromium alloy powder are melted at high temperature and added to the alloy melt prepared in Step 1. After mixing and refining, the mixture is subjected to solution treatment and quenching, and then cast to obtain the nickel-chromium alloy. Step 3: The nickel-chromium alloy obtained in Step 2 is crushed, sieved, and then ball-milled in a ball mill to obtain nickel-chromium alloy powder. Step 4: Take titanium dioxide modified tungsten carbide particles, Al2O3 powder, and acidified carbon nanotubes, dry them in an oven, and then mix them with the ball-milled nickel-chromium alloy powder from Step 3 to obtain a mixed powder. Step 5: Place the mixed powder from Step 4 into a mold, apply pressure, press and shape it, and then sinter it at high temperature to obtain a wear-resistant and high-temperature resistant nickel-chromium alloy material. The preparation of the titanium dioxide-modified tungsten carbide particles in step 4 includes the following steps: S1, clean and dry the tungsten carbide particles to ensure that there are no impurities or moisture on their surface; S2, dissolve tetrabutyl titanate in anhydrous ethanol to prepare a titanium dioxide precursor solution for later use. S3, mix tungsten carbide particles with titanium dioxide precursor solution, stir evenly with a stirrer, maintain stirring and add deionized water to hydrolyze tetrabutyl titanate to form titanium dioxide, heat up and keep warm, then cool naturally to room temperature to obtain TiO2-WC mixture. S4. After filtering the TiO2-WC mixture, the insoluble matter is dried in an oven to remove residual anhydrous ethanol and water, resulting in a dried TiO2-WC mixture. S5. The dried TiO2-WC mixture is placed in a tube furnace for heat treatment, so that titanium dioxide forms a uniform coating on the surface of tungsten carbide particles, and titanium dioxide modified tungsten carbide particles are obtained.

2. The wear-resistant and high-temperature resistant nickel-chromium alloy material according to claim 1, characterized in that, The temperature for preparing the alloy melt in step 1 is 3200℃~3800℃, the vacuum degree is 0.09MPa, and the time is 1~4h.

3. The wear-resistant and high-temperature resistant nickel-chromium alloy material according to claim 1, characterized in that, In step 2, the high-temperature melting temperature is 3200℃~3800℃ and the time is 1~2h; the mixing and refining temperature is 1100℃~1600℃ and the time is 1~3h; the solution treatment and quenching treatment are carried out in air, with a solution temperature of 950℃~1100℃ and a holding time of 15min~90min, and a quenching temperature of 1050℃~1200℃ and a quenching time of 5~10min.

4. The wear-resistant and high-temperature resistant nickel-chromium alloy material according to claim 1, characterized in that, The nickel-chromium alloy powder obtained by ball milling in step 3 has a particle size of 100~800 mesh.

5. The wear-resistant and high-temperature resistant nickel-chromium alloy material according to claim 1, characterized in that, In step 4, the titanium dioxide-modified tungsten carbide has a particle size of 20-100 μm, the Al2O3 powder has a particle size of 75 μm, and the acidified carbon nanotubes have a particle size of 10-20 nm and a length of 30 nm; the drying process is carried out at 80°C for 7-10 h.

6. The wear-resistant and high-temperature resistant nickel-chromium alloy material according to claim 1, characterized in that, The pressure mentioned in step 5 is 300~500MPa, and the high-temperature sintering is carried out in an argon atmosphere at a temperature of 900℃~1200℃ for 1~3h.

7. The wear-resistant and high-temperature resistant nickel-chromium alloy material according to claim 1, characterized in that, The cleaning described in S1 involves sequentially ultrasonically cleaning with acetone and deionized water for 10-30 minutes, followed by drying in an oven at 70°C for 30-60 minutes. In S2, the volume ratio of tetrabutyl titanate to anhydrous ethanol is 1:(1.5-2.5). In S3, the proportion of tungsten carbide particles to tetrabutyl titanate is (1-1.5 g) / mL, the stirring speed is 50-100 rpm, the stirring time is 20-60 minutes, the volume ratio of deionized water to tetrabutyl titanate is (0.8-1.2):1, and the temperature is raised to 60-90°C and held for 1 hour. In S4, the drying process is carried out at 80°C for 30-60 minutes. In S5, the heat treatment is carried out under nitrogen protection at a temperature of 500-800°C, a heating rate of 5°C / min, and a holding time of 30 minutes to 2 hours.

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