A Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components and its preparation method

Abstract

The application discloses a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for a sealing element and a preparation method thereof. The wear-resistant coating comprises the following components in percentage by mass: 12-16% of WC, 5-15% of nano TiN, 3.5-7.5% of a nano ZrO2 / CeO2 rare earth compound, and the balance of a Fe-based alloy powder. The preparation method comprises the following steps: uniformly mixing the WC powder, the nano TiN powder, the nano ZrO2 / CeO2 rare earth compound powder and the Fe-based alloy powder in a manner of combining ultrasonic waves and ball milling, preparing cladding raw materials, cladding the cladding raw materials on the surface of a sealing ring by using a laser cladding technology, and obtaining the Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for the sealing element. The wear-resistant coating prepared by the application has good strength and toughness, good corrosion resistance and is not easy to peel off.

Description

Technical Field

[0001] This invention relates to the field of surface coating technology for mechanical seals, specifically to a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components and its preparation method. Background Technology

[0002] Modern mechanical seals operate under increasingly demanding conditions, leading to a rise in dynamic mechanical seal failures and scrapping due to wear. The performance of sealing coating materials often determines whether a sealing system can achieve its intended goals. Therefore, developing low-cost, high-wear-resistant coatings for sealing surfaces is a pressing challenge for the modern mechanical seal industry.

[0003] Fe-based coatings, as a low-cost coating material, possess excellent strength, impact toughness, and wear resistance, while also exhibiting good resistance to high-temperature oxidation, chlorine pitting, and sulfidation. Embedding hard particles (TiN and WC) within a tougher iron-based phase can effectively improve the coating's wear resistance and corrosion resistance. Due to mutual wetting with Fe and good bonding strength, TiN and WC particle-reinforced Fe-based coatings exhibit high hardness and impact toughness, making them suitable for manufacturing dynamic mechanical seals requiring high wear resistance. In recent years, the preparation of hard particle-reinforced Fe-based coatings using processes such as thermal spraying, welding, and laser cladding to improve the wear resistance of components has become a research hotspot.

[0004] With the increasing complexity of the service conditions of mechanical seals, traditional WC and TiN-reinforced Fe-based coatings can no longer meet the ever-higher requirements for the service life of seals. When the TiN and WC particles in the cladding coating are large, they are prone to peeling off from the substrate, reducing the coating's wear resistance; when the Fe-based material grains are long and coarse, its strength and toughness decrease, weakening its supporting effect on the WC and TiN particles. Therefore, developing a seal surface coating with higher wear resistance has become one of the urgent problems to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components and its preparation method, which has good toughness, good corrosion resistance and is not easy to peel off.

[0006] In one aspect of the invention, a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components is provided. According to an embodiment of the invention, the wear-resistant coating comprises the following components in weight percentages: WC 12%-16%, nano-TiN 5%-15%, nano-ZrO2 / CeO2 rare earth compound 3.5%-7.5%, and the balance being Fe-based alloy powder.

[0007] In addition, the Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components according to the above embodiments of the present invention may also have the following additional technical features:

[0008] In some embodiments of the present invention, the Fe-based alloy powder is a FeCrMoPCSi system, and the particle size of the Fe-based alloy powder is 30-50 μm; the particle size of WC is 20-30 μm, the main purpose of which is to improve the wettability between the reinforcing WC powder phase and the Fe-based alloy parent phase and reduce the oxidation and decarburization of the WC ceramic phase during laser cladding; the average particle size of nano-TiN is 20-25 nm, and the average particle size of the nano-ZrO2 / CeO2 rare earth compound is 60-75 nm.

[0009] In some embodiments of the present invention, the Fe-based alloy powder comprises the following components by mass percentage: C 0.5%-1.2%, P 0.5%-0.8%, Cr 8%-10%, Mo 1.0%-1.5%, Si ≤2%, and the remainder being Fe.

[0010] In some embodiments of the present invention, the thickness of the Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating is 15-25 μm.

[0011] In another aspect of the present invention, a method for preparing a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components is provided. According to an embodiment of the present invention, the method includes the following steps: WC powder, nano-TiN powder, nano-ZrO2 / CeO2 rare earth compound powder, and Fe-based alloy powder are mixed uniformly using a combination of ultrasonic and ball milling methods to prepare a cladding material; the cladding material is then clad onto the surface of a sealing ring using laser cladding technology to obtain the Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components.

[0012] Furthermore, the method for preparing a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components according to the above embodiments of the present invention may also have the following additional technical features:

[0013] In some embodiments of the present invention, the ultrasonic mixing time is 8-15 minutes.

[0014] In some embodiments of the present invention, the ball-to-material ratio during the ball milling process is 2-4:1, the grinding balls are cemented carbide balls, the grinding medium is anhydrous ethanol, the rotation speed is 300-400 r / min, the ball milling is carried out under argon protection, the mixing time is 200-300 minutes, and the powder is dried after mixing.

[0015] In some embodiments of the present invention, before laser cladding, the sealing ring workpiece is subjected to surface degreasing, rust removal, sandblasting, and pre-cladding treatment in sequence. The pre-cladding treatment includes the following steps: cleaning the area of ​​the sealing ring to be laser clad, leveling areas with obvious defects, and using an indicator flaw detection method to inspect the cleaned sealing surface to determine whether there are any obvious defective areas; the high-speed laser cladding head is installed at the end of the CNC machine tool and, under the control of the CNC system, achieves relative movement with the surface of the sealing part; the cladding trajectory is adjusted by the PLC control system; and argon gas serves as both the carrier gas and the protective gas.

[0016] In some embodiments of the present invention, the laser used for laser cladding is a short-wavelength pulsed laser, and the process parameters of the laser cladding are as follows: laser power is 2300-2500W, cladding rate is 20-25m / min, overlap rate is 60%-65%, powder feeding amount is 15-20g / min, focal radius is 0.8-1mm, and focal length is 12-15mm.

[0017] This invention employs a high-speed laser cladding process. While ensuring good forming quality of the single-layer coating, it prepares a high-speed laser cladding coating with a cladding rate of 20-25 m / min by varying the cladding rate. By carefully configuring the entire coating process and ensuring sufficient cooling rate, an amorphous coating with a thickness of 0.1-0.2 mm is formed on a high-glass-forming iron-based substrate. This maintains the original properties of the substrate and the composition ratio of the coating while ensuring metallurgical bonding at the interface. Multiple overlapping cladding operations can form amorphous coatings with millimeter-thickness, resulting in low material consumption and a substrate utilization rate exceeding 95%.

[0018] In some embodiments of the present invention, the laser is near-infrared light or blue light.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] (1) The present invention can prepare a wear-resistant coating on the surface of seals of various shapes, and its hardness can be increased from HRC35 to HRC50-55 compared with uncoated seals.

[0021] (2) On the basis of Fe-based WC wear-resistant coating composition, nano-TiN is added. Nano-TiN can be uniformly distributed in Fe-based amorphous matrix coating, playing a role in dispersion strengthening; at the same time, nano-TiN can serve as non-spontaneous nucleation core of WC, significantly refining WC, enhancing the bonding strength between WC and matrix Fe, and improving anti-stripping performance.

[0022] (3) On the basis of Fe-based TiN and WC wear-resistant coating composition, nano ZrO2 / CeO2 is added, which can serve as a non-spontaneous nucleation core of WC, refine WC and TiN, enhance the bonding strength between WC and the matrix Fe, and improve the anti-stripping performance; in addition, ZrO2 / CeO2 can serve as a non-spontaneous nucleation core of amorphous Fe-based matrix, refine the microstructure of the matrix Fe, and have a strengthening effect on the matrix Fe.

[0023] (4) The present invention adopts a mixing method that combines ultrasonic and ball milling to better disperse agglomerated powder, which is beneficial to alloying.

[0024] (5) The present invention can make parts of various shapes have wear-resistant surfaces by laser cladding, which has a very broad market space, and the coating of the present invention can be widely used in metallurgy, machinery, mining, coal, petroleum, construction and other fields. Attached Figure Description

[0025] Figure 1 This is a SEM scan of the Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating used for sealing components in Example 1 of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1

[0028] A wear-resistant coating for sealing components based on Fe, comprising: 10 kg of WC with a particle size of 20 μm, 4 kg of TiN powder with an average particle size of 20 nm, 3 kg of ZrO2 / CeO2 powder with an average particle size of 60 nm, and 50 kg of Fe-based alloy powder with a particle size of 30 μm.

[0029] The Fe-based alloy powder is a FeCrMoPCSi system with a particle size of 30 μm and a chemical composition of: C: 0.25 kg, P: 0.25 kg, Cr: 4 kg, Mo: 0.5 kg, Si: 1 kg, Fe: 44 kg. The WC tungsten carbide powder has a particle size of 20 μm, which is mainly used to improve the wettability between the reinforcing WC powder phase and the Fe-based alloy matrix phase and reduce the oxidation and decarburization of the WC ceramic phase during laser cladding. The average particle size of TiN is 20 nm. The average particle size of the ZrO2 / CeO2 rare earth compound is 60 nm.

[0030] A method for preparing a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components includes the following steps:

[0031] (1) Mixing powder

[0032] First, WC powder, TiN powder, ZrO2 / CeO2 powder, and Fe-based alloy powder were ultrasonically premixed for 10 minutes. Then, they were ball-milled. During the ball-milling process, the ball-to-powder ratio was 2:1, the grinding balls were cemented carbide balls, the grinding media was anhydrous ethanol, the speed was 300 r / min, and the mixing time was 200 minutes under the protection of 99.9% pure argon gas. Finally, the powder was dried in a vacuum drying oven to obtain the cladding raw material.

[0033] (2) Pre-treatment of the seals

[0034] The sealing component is a hard alloy sealing ring. The workpiece is subjected to surface degreasing, rust removal, sandblasting (further cleaning), and pre-cladding treatment (cleaning the area to be laser cladding and leveling the area with obvious defects; using the indicator test method to test the cleaned sealing surface to determine whether there are any obvious defective areas).

[0035] (3) The cladding material is clad onto the sealing component by laser cladding.

[0036] The high-speed laser cladding head is installed at the end of the CNC machine tool. Under the control of the CNC system, it achieves relative movement with the surface of the sealing component. The cladding trajectory is adjusted by the PLC control system. Argon gas serves as both the carrier gas and the protective gas. The cladding process is carried out using a short-wavelength pulsed high-speed red laser with high absorption rate. Under the premise of ensuring good forming quality of the single-layer coating, the high-speed laser cladding coating with a cladding rate of 20-25 m / min can be prepared by changing the cladding rate.

[0037] The process parameters for the entire coating process are as follows: a 3000W semiconductor fiber laser is used, paired with an LC300 laser head, using near-infrared light. The laser power is 2300W, the cladding rate is 20m / min, the overlap rate is 60%, the powder feed rate is 15g / min, the focal radius is 0.8mm, and the focal length is 12mm. Sufficient cooling rate is ensured, allowing the iron-based substrate with high glass-forming ability to form an amorphous coating with a thickness of 0.1-0.2mm. This maintains the original properties of the substrate and the composition ratio of the coating, while also ensuring metallurgical bonding at the interface. Material consumption is low, and the substrate utilization rate can reach over 95%.

[0038] Figure 1 The Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating samples for sealing components exhibit uniform surface microstructure and grain size, significantly contributing to improved wear resistance.

[0039] The Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating achieved a hardness of HRC50. After a friction and wear test with a load of 5 N, a friction radius of 2 mm, a test temperature of 20 °C, a motor speed of 560 r / min, and a time of 30 min, the wear rate of the seal was 3.5 mm. 3 / N / m.

[0040] Example 2

[0041] A Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components comprises the following components: 10 kg of WC with a particle size of 22 μm, 4 kg of nano-TiN with an average particle size of 22 nm, 3 kg of nano-ZrO2 / CeO2 powder with an average particle size of 65 nm, and 50 kg of Fe-based alloy powder with a particle size of 35 μm.

[0042] The Fe-based alloy powder is of the FeCrMoPCSi system, with the following chemical composition: C: 0.4 kg, P: 0.3 kg, Cr: 4.5 kg, Mo: 0.6 kg, Si: 0.9 kg, Fe: 43.3 kg; the WC powder is nickel-coated tungsten carbide powder with a particle size range of 22 μm, and the average particle size of nano-TiN is 22 nm; the average particle size of nano-ZrO2 / CeO2 rare earth compounds is 65 nm.

[0043] A method for preparing a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components includes the following steps:

[0044] (1) Mixing powder

[0045] First, WC powder, TiN powder, ZrO2 / CeO2 powder, and Fe-based alloy powder were ultrasonically premixed for 10 minutes. Then, they were ball-milled at a ball-to-powder ratio of 3:1, using cemented carbide balls as the grinding media and anhydrous ethanol at a speed of 350 r / min. The mixing time was 250 minutes under the protection of 99.9% pure argon gas. Finally, the powder was dried in a vacuum drying oven.

[0046] (2) Pre-treatment of the seals

[0047] Pre-treatment process: including degreasing and derusting of the surface of the cemented carbide sealing ring workpiece → sandblasting (further cleaning) → pre-cladding treatment (cleaning the area to be laser cladding, leveling the area with obvious defects; using the indicator method to detect defects on the cleaned sealing surface to determine whether there are any obvious defect areas).

[0048] (3) The cladding material is clad onto the sealing component by laser cladding.

[0049] A high-speed laser cladding head is installed at the end of a CNC machine tool. Under the control of the CNC system, it achieves relative movement with the surface of the sealing component. The cladding trajectory is adjusted by a PLC control system, and argon gas serves as both the carrier gas and the protective gas. A high-absorption, short-wavelength pulsed high-speed red laser is used for the cladding process. While ensuring good forming quality of the single-layer coating, a high-speed laser cladding coating with a cladding rate of 20-25 m / min is prepared by changing the cladding rate.

[0050] The process parameters for the entire coating process are as follows: a 3000W semiconductor fiber laser is used, paired with an LC300 laser head, using near-infrared light. The laser power is 2400W, the cladding rate is 23m / min, the overlap rate is 62%, the powder feed rate is 18g / min, the focal radius is 0.9mm, and the focal length is 14mm. Sufficient cooling rate is ensured, allowing the iron-based substrate with high glass-forming ability to form an amorphous coating with a thickness of 0.1-0.2mm. This maintains the original properties of the substrate and the composition ratio of the coating, while also ensuring metallurgical bonding at the interface. Material consumption is low, and the substrate utilization rate can reach over 95%.

[0051] The Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating achieved a hardness of HRC53. After a friction and wear test with a load of 5 N, a friction radius of 2 mm, a test temperature of 20 °C, a motor speed of 560 r / min, and a time of 30 min, the wear rate was 4.2 mm. 3 / N / m.

[0052] Example 3

[0053] A wear-resistant coating for sealing components based on Fe, comprising the following components: 10 kg of WC with a particle size of 25 μm, 4 kg of nano-TiN with an average particle size of 25 nm, 3 kg of nano-ZrO2 / CeO2 with an average particle size of 75 nm, and 50 kg of Fe-based alloy powder with a particle size of 30 μm.

[0054] The Fe-based alloy powder is of the FeCrMoPCSi system, with the following chemical composition: C: 0.6 kg, P: 0.4 kg, Cr: 5 kg, Mo: 0.75 kg, Si: 0.75 kg, Fe: 42.5 kg; the WC powder is nickel-coated tungsten carbide powder with a particle size range of 25 μm, and the average particle size of nano-TiN is 25 nm; the average particle size of nano-ZrO2 / CeO2 rare earth compounds is 75 nm.

[0055] A method for preparing a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components includes the following steps:

[0056] (1) Mixing powder

[0057] First, WC powder, TiN powder, ZrO2 / CeO2 powder, and Fe-based alloy powder were ultrasonically premixed for 10 minutes. Then, they were ball-milled at a ball-to-powder ratio of 4:1, using cemented carbide balls as the grinding media and anhydrous ethanol at a speed of 400 r / min. The mixing time was 300 minutes under the protection of 99.9% pure argon gas. Finally, the powder was dried in a vacuum drying oven.

[0058] (2) Pre-treatment of the seals

[0059] Pre-treatment process: including degreasing and derusting of the surface of the cemented carbide sealing ring workpiece → sandblasting (further cleaning) → pre-cladding treatment (cleaning the area to be laser cladding, leveling the area with obvious defects; using the indicator method to detect defects on the cleaned sealing surface to determine whether there are any obvious defect areas).

[0060] (3) The cladding material is clad onto the sealing component by laser cladding.

[0061] A high-speed laser cladding head is installed at the end of a CNC machine tool. Under the control of the CNC system, it achieves relative movement with the surface of the sealing component. The cladding trajectory is adjusted by a PLC control system, and argon gas serves as both the carrier gas and the protective gas. A high-absorption, short-wavelength pulsed high-speed blue laser is used for the cladding process. While ensuring good forming quality of the single-layer coating, a high-speed laser cladding coating with a cladding rate of 20-25 m / min is prepared by changing the cladding rate.

[0062] The process parameters for the entire coating process are as follows: a 3000W semiconductor fiber laser is used, paired with an LC300 laser head, using near-infrared light. The laser power is 2500W, the cladding rate is 25m / min, the overlap rate is 65%, the powder feed rate is 20g / min, the focal radius is 1.0mm, and the focal length is 15mm. Sufficient cooling rate is ensured, allowing the iron-based substrate with high glass-forming ability to form an amorphous coating with a thickness of 0.1-0.2mm. This maintains the original properties of the substrate and the composition ratio of the coating, while also ensuring metallurgical bonding at the interface. Material consumption is low, and the substrate utilization rate can reach over 95%.

[0063] The Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating achieved a hardness of HRC55. After a friction and wear test with a load of 5 N, a friction radius of 2 mm, a test temperature of 20 °C, a motor speed of 560 r / min, and a time of 30 min, the wear rate was 4.8 mm. 3 / N / m.

[0064] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components, characterized in that, The composition comprises the following components by mass percentage: WC 12%-16%, nano-TiN 5%-15%, nano-ZrO2 / CeO2 3.5%-7.5%, with the balance being Fe-based alloy powder. The Fe-based alloy powder is a FeCrMoPCSi system, with a particle size of 30-50 μm. The particle size of WC is 20-30 μm, the average particle size of nano-TiN is 20-25 nm, and the average particle size of nano-ZrO2 / CeO2 is 60-75 nm. The Fe-based alloy powder comprises the following components by mass percentage: C 0.5%-1.2%, P 0.5%-0.8%, Cr 8%-10%, Mo 1.0%-1.5%, Si≤2%, with the balance being Fe.

2. The Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components according to claim 1, characterized in that: The thickness of the Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating is 15-25 μm.

3. A method for preparing a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components according to claim 1 or 2, characterized in that, Includes the following steps: WC powder, nano TiN powder, nano ZrO2 / CeO2 powder, and Fe-based alloy powder are mixed evenly using a combination of ultrasonic and ball milling methods to prepare a cladding material. The cladding material is then clad onto the surface of the sealing ring using laser cladding technology to obtain the Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for the sealing component.

4. The method for preparing a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components according to claim 3, characterized in that: The ultrasonic mixing time is 8-15 minutes.

5. The method for preparing a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components according to claim 3, characterized in that: During the ball milling process, the ball-to-material ratio is 2-4:1, the grinding balls are cemented carbide balls, the grinding medium is anhydrous ethanol, the rotation speed is 300-400 r / min, the ball milling is carried out under argon protection, the mixing time is 200-300 minutes, and the powder is dried after mixing.

6. The method for preparing a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components according to claim 3, characterized in that: Before laser cladding, the sealing ring workpiece is subjected to surface degreasing, rust removal, sandblasting, and pre-cladding treatment in sequence.

7. The method for preparing a Fe-based WC / TiN / ZrO2 / CeO2 wear-resistant coating for sealing components according to claim 3, characterized in that: The laser cladding process parameters are as follows: laser power is 2300-2500W, cladding rate is 20-25m / min, overlap rate is 60%-65%, powder feeding rate is 15-20g / min, focal radius is 0.8-1mm, focal length is 12-15mm, and the laser is near-infrared light or blue light.

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