In-situ ti c / fe-based cermet composite wear-resistant powder, coating and preparation method

Abstract

The present application relates to a kind of in situ TiC / Fe base metal ceramic composite wear-resistant powder, coating and preparation method, belong to laser melting deposition technical field.Compared with prior art in situ TiC / Fe base composite wear-resistant coating preparation technology, the graphite (or nickel-coated graphite) content in the powder formula of the present application is lower, can effectively improve the uniformity of in situ TiC ceramic reinforced phase distribution in coating, effectively improve the wear resistance of coating, can realize the preparation of high-performance repair or strengthening coating of low crack sensitivity of component surface.The composite coating is prepared by laser melting deposition technology process after pure Ti, nickel-coated graphite and Fe55 alloy powder are ball milled according to certain ratio.The uniformly distributed in situ submicron TiC particles in Fe base composite coating have pinning effect on surrounding "soft metal", inhibit crack propagation by "deflection", and TiC particles can continuously play the role of wear-resistant framework under the support of surrounding metal phase, finally improve the wear resistance of coating material.

Description

Technical Field

[0001] This invention belongs to the field of laser melting deposition technology, specifically relating to an in-situ TiC / Fe-based metal-ceramic composite wear-resistant powder, coating, and preparation method thereof. Background Technology

[0002] With the rapid development of underground space utilization, tunnel boring machines (TBMs) are approaching the end of their service life. Their operating conditions are harsh, and the main form of damage and failure is surface wear, which often occurs in critical steel components such as the main bearings, sealing runways, and cutterheads. Repairing damaged high-value core components with high-performance wear-resistant coatings can extend the service life of TBMs and improve market responsiveness.

[0003] Metal-based ceramic composite coatings prepared by laser melting deposition possess both the high strength and high plasticity of metallic materials and the excellent mechanical properties of ceramic materials, such as high hardness, high temperature resistance, and wear resistance. This effectively reduces surface wear and corrosion damage to components, improving their service life and reliability. In the field of cladding powder materials, iron-based alloy coatings are widely used in steel components due to their high interfacial bonding strength and low cost. However, the limited hardness and poor wear resistance of iron-based alloys hinder their application in harsh service environments.

[0004] Particle-reinforced metal matrix composites, primarily composed of ceramic particles such as TiC, WC, NbC, and Cr3C2, exhibit excellent wear resistance of the ceramic phase and good plasticity and toughness of the metal binder phase. Among these, the TiC phase, with its low density, high hardness, good wear resistance, and good thermal stability with iron-based alloys, has become one of the most promising reinforcing phases for steel. Currently, in research and applications, metal matrix ceramic composite coatings are often prepared using an additive method, where ceramic particles are added to metal alloy powder and deposited via laser melting to retain them within the coating, serving as a reinforcing phase to improve the wear resistance of the metal matrix coating. However, this preparation method is not only costly but also suffers from interfacial contamination issues due to the added TiC particles in the coating, hindering further improvement in the wear resistance of the resulting coatings.

[0005] To address the drawbacks of added ceramic phases, researchers have developed in-situ ceramic phase-reinforced metal-based ceramic composite coatings. Studies have confirmed that in-situ TiC within the metal-based coating avoids interface contamination issues associated with added reinforcing phases, improves the wettability between the ceramic phase and the metal substrate, and significantly enhances the coating's wear resistance. Current research primarily uses pure Ti powder and titanium-iron alloys as titanium sources, and graphite and carbide ceramic phases as precursor powders for in-situ self-generated TiC in metal-based coatings prepared by laser melting deposition. However, due to the poor flowability of the mixed powders, a pre-powder method is generally used to prepare in-situ self-generated TiC-reinforced metal coatings. This method is limited by the complexity of the process, resulting in low preparation efficiency, poor process flexibility, and poor surface quality, making it unsuitable for high-performance additive repair of complex components such as main bearing sealing runways and hydraulic columns using laser melting deposition. To improve the wear resistance of titanium alloy surfaces, patent CN 111575703 B discloses a ceramic-reinforced graphite self-lubricating coating for titanium alloy surfaces and its preparation method. CN 110756797 B discloses an alloying material modified with nano-rare earth oxides, an alloying layer, and its preparation method. The disclosed cladding materials contain a relatively high content of nickel-coated graphite (greater than 25 wt.%, of which the graphite content is greater than 6.25 wt.%). The higher nickel-coated graphite content allows the graphite portion to remain as a lubricating phase in the coating. However, the increased carbon content in the alloy, on the one hand, increases the crack susceptibility during coating preparation and service; on the other hand, since nickel-coated graphite is not a spherical powder, excessive addition will worsen the flowability of the mixed powder, thus affecting the uniformity of the deposited coating composition. Furthermore, compared with iron-based composite materials, the laser deposition preparation cost of this nickel-based coating powder formulation is higher, and its interfacial bonding performance with the steel substrate needs further verification.

[0006] Therefore, to further improve the wear resistance of iron-based composite coatings and solve problems such as low preparation efficiency, high crack sensitivity, and uneven distribution of ceramic phase in in-situ TiC phase-reinforced metal-based composite coatings, it is urgent to develop a powder formulation for in-situ self-generated TiC-reinforced iron-based composite coatings with low graphite (or nickel-coated graphite) content. This would enable the use of laser melting deposition coaxial powder feeding technology to achieve high-efficiency and high-quality remanufacturing repair of key components such as rings and shafts. This is of great significance for promoting the high-performance remanufacturing application of TiC / Fe-based composite wear-resistant coatings in key components of engineering machinery such as tunnel boring machines and hydraulic columns. Summary of the Invention

[0007] The technical problem to be solved by this invention is: addressing the issues of insufficient wear resistance, low preparation efficiency, high crack sensitivity, and uneven ceramic phase distribution in TiC / Fe-based composite wear-resistant coatings prepared by existing laser melting deposition powder formulations. This invention proposes a laser melting deposition in-situ self-generated TiC-reinforced Fe-based coating powder formulation and preparation method to solve the wear problem of steel components such as tunnel boring machine sealing runways, and to meet the service performance requirements under actual working conditions.

[0008] To achieve the above objectives, the present invention can be implemented through the following measures:

[0009] In a first aspect, the present invention provides a TiC / Fe cermet composite wear-resistant powder, which is composed of nickel-coated graphite powder, pure Ti powder, and Fe55 alloy powder; wherein the nickel-coated graphite powder (containing 20% ​​graphite) has a mass fraction of 5%–15%, the pure Ti powder has a mass fraction of 4%–12%, and the Fe55 alloy powder has a mass fraction of 73%–91%, and the sum of the mass percentages of each component is 100%; the addition of a small amount of nickel-coated graphite to the mixed powder has two advantages: firstly, it has a smaller impact on the flowability of the iron-based alloy powder, ensuring that each powder component enters the molten pool according to the designed ratio; secondly, it has a smaller impact on the crack sensitivity of the coating, reducing the possibility of cracking of the coating during preparation and service.

[0010] As a further technical solution, the Fe55 alloy powder is a spherical iron-based self-fluxing alloy powder composed of 16%–18% Cr, 3.5%–4% B, 3%–4% Si, 10%–13% Ni, 0.7%–1.0% C, and the balance iron. The Fe55 alloy powder has similar thermophysical parameters to the 42CrMo steel substrate, which helps alleviate the stress at the coating interface, ensures the coating bonding strength, and reduces the remanufacturing and repair costs of high-value components.

[0011] As a further technical solution, the particle sizes of the pure Ti powder, nickel-coated graphite powder, and iron-based alloy powder are 53–105 μm, 15–45 μm, and 75–105 μm, respectively, and the mass fraction ratio of pure Ti powder to nickel-coated graphite powder is 4:5. Similar particle sizes help ensure the flowability of the mixed powder, resulting in a composite coating with good surface quality and uniform in-situ ceramic phase distribution prepared using coaxial powder feeding. The mass fraction of Ti powder to nickel-coated graphite ensures that Ti atoms and C atoms combine in a 1:1 ratio within the laser molten pool to form TiC.

[0012] As a further technical solution, the nickel-coated graphite powder is a coated powder composed of 20% graphite and 80% Ni, wherein the graphite is coated with nickel metal. Because nickel metal has a higher density and hardness than graphite, it is less prone to breakage during ball milling and powder feeding cladding. Furthermore, the particle weight of the nickel-coated graphite powder is similar to that of Fe55 iron-based alloy powder, resulting in good flowability of the mixed cladding powder, allowing for coaxial powder feeding to prepare the cladding layer.

[0013] The nickel coating on the graphite surface has a similar melting point to the Fe55 iron-based alloy. Under high-energy laser irradiation, the outer nickel coating melts first, reducing spatter loss from the high-melting-point graphite (graphite's melting point is approximately 3773 K), allowing it to react with pure titanium in situ to form the TiC ceramic reinforcing phase according to the designed ratio. Furthermore, the nickel layer improves the wettability of the iron-based alloy molten pool and the affinity for graphite, which is beneficial for improving the uniformity of the in-situ TiC distribution.

[0014] A second aspect of the present invention provides a laser melting deposition method for preparing a TiC / Fe-based composite wear-resistant coating, comprising the following steps:

[0015] Step 1: Mix nickel-coated graphite, pure Ti, and Fe55 alloy powder evenly, wet ball mill, and dry to obtain TiC / Fe-based composite powder; wherein the mass fraction of nickel-coated graphite powder is 5%–15%, the mass fraction of pure Ti powder is 4%–12%, and the mass fraction of Fe55 alloy powder is 73%–91%, and the sum of the mass percentages of each component is 100%; and the mass fraction ratio of pure Ti powder to nickel-coated graphite powder is 4:5;

[0016] Step 2: Process the surface of the part to obtain the pre-processed part;

[0017] Step 3: The TiC / Fe-based composite powder obtained in Step 1 is clad onto the pretreated part surface using laser melting deposition method to form a TiC / Fe-based wear-resistant coating containing in-situ submicron TiC hard phase particles.

[0018] As a further technical solution, the in-situ submicron TiC hard phase particles are uniformly distributed in the coated metal matrix.

[0019] This invention reveals that in the high-temperature environment of the molten pool, pure Ti and graphite C atoms spontaneously combine in situ to form submicron in-situ TiC, which is uniformly dispersed in the iron-based coating. Its interface is pure, exhibiting high bonding strength with the coating substrate. Under shear friction, it acts as a wear-resistant skeleton, anchoring the surrounding "soft metal" structure and inhibiting wear and peeling of the coating material. The coating material prepared by laser melting deposition using this composite powder formulation possesses excellent wear resistance, good crack resistance, and also exhibits good processability and surface smoothness.

[0020] A third aspect of the present invention provides an in-situ TiC / Fe-based cermet composite wear-resistant coating, which is prepared by the preparation method described above. The TiC / Fe-based wear-resistant coating can be used in the remanufacturing of key components such as the main bearing sealing runway and the cutterhead of a tunnel boring machine.

[0021] Because the TiC / Fe-based wear-resistant coating prepared by this invention has excellent wear resistance and good crack resistance, it is expected to be widely used in the preparation of wear-resistant coatings on the surfaces of key components such as the main bearing sealing runway and cutterhead of tunnel boring machines.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. The powder formulation of this invention has a low graphite (or nickel-coated graphite) content, which improves the problems of low coating preparation efficiency and high crack sensitivity. The addition of a small amount of nickel-coated graphite has a small impact on the flowability of iron-based alloy powder, which can ensure the proportion of each powder component; on the other hand, it has a small impact on the crack sensitivity of the coating, which can reduce the possibility of cracking during coating preparation and service.

[0024] 2. This invention can improve the wear resistance of conventional iron-based alloy coatings. In-situ submicron TiC hard phase particles, uniformly distributed within the coating metal matrix, are prepared by laser melting deposition. This improves the coating's microstructure and interface structure, providing a pinning effect on the surrounding "soft metal." Simultaneously, under shear friction loads, it inhibits crack propagation by "deflecting" cracks. Furthermore, supported by the surrounding metal phase, the TiC particles continuously function as a wear-resistant skeleton, ultimately improving the wear resistance of the coating material.

[0025] 3. This invention boasts low preparation cost, strong practicality, and ease of application and promotion. Compared to nickel-based alloys, which are currently widely used in research, using iron-based alloys as the main cladding powder is more cost-effective and offers better bonding performance with steel-based components. The coaxial powder feeding process using laser melting deposition allows for the preparation of high-performance repair or reinforcement coatings on the surfaces of rings, shafts, and complex components, offering greater flexibility and higher efficiency. Attached Figure Description

[0026] Figure 1 This is the XRD phase distribution diagram of the TiC / Fe-based composite coating in Example 2 of the present invention;

[0027] Figure 2(a) and Figure 2(b) are SEM images of the TiC / Fe-based composite coatings of Example 2 and Comparative Example 2 of the present invention, respectively.

[0028] Figures 3(a) and 3(b) are TEM images of the TiC / Fe-based composite coating in Example 2 of the present invention;

[0029] Figures 4(a), 4(b), and 4(c) show the surface wear marks morphology of the TiC / Fe-based composite coating in Example 2 of the present invention. Detailed Implementation

[0030] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0031] The TiC / Fe-based cermet composite powder disclosed in this invention comprises, by mass fraction, 5%~15% nickel-coated graphite, 4%~12% pure Ti, and 73%~91% Fe55; the sum of the weight percentages of each component is 100%.

[0032] The wear-resistant TiC / Fe-based cermet composite coating of the present invention is prepared by laser melting deposition using composite powder of the above-mentioned formulation. The prepared coating has a thickness of 0.8–0.9 mm, good density, and metallurgical bonding with the substrate. TiC particles with an average particle size of 0.8 µm are uniformly distributed within the coating, the interface is pure and free of contaminants, and the Vickers hardness of the coating is ≥600 HV. 0.5 .

[0033] The preparation method of the above-mentioned wear-resistant TiC / Fe-based cermet composite powder and coating includes the following steps:

[0034] Step 1: Select pure Ti powder with a particle size of 53–105 μm, nickel-coated graphite powder with a particle size of 15–45 μm (composition: 20% C, 80% Ni), and iron-based alloy powder with a particle size of 75–105 μm; the mass fraction ratio of pure Ti powder to nickel-coated graphite powder is 4:5. Weigh the above powders according to the following mass ratio: 5%–15% nickel-coated graphite, 4%–12% pure Ti, 73%–91% Fe55 (17.05% Cr, 3.5% B, 3.5% Si, 10% Ni, 0.77% C, and balance iron).

[0035] Step 2: After the mixing ratio is completed, place the mixed powder in a ball mill jar and add anhydrous ethanol to two-thirds of the jar. Stir in an ultrasonic stirrer for 30 minutes to make a powder slurry. Add grinding balls at a ball-to-powder ratio of 3:2, then seal the ball mill jar and place it in a planetary ball mill at a speed of 180 rpm for 30 minutes to achieve homogenization of the composite powder without damaging the original powder particle morphology.

[0036] Step 3: Pour the mixed powder slurry into a stainless steel pan and spread it evenly, then place it under a vacuum of less than 10 degrees. -2 ~10 -4 Dry in a vacuum drying oven at Pa% for 2-3 hours; after drying, separate the stainless steel balls and powder with a stainless steel sieve to obtain a uniform mixed powder, and seal for later use.

[0037] Step 4: Pretreatment of the cladding substrate. Clean the 42CrMo steel substrate with acetone to remove surface oil and other impurities, then ultrasonically clean it with anhydrous ethanol for 10 minutes, and blow it dry for later use.

[0038] Step 5: The composite powder prepared in Step 3 is clad using an RFC-C6000X laser melting deposition system. Under an argon protective atmosphere, a 6 kW fiber laser is used to prepare the cladding coating. The process parameters are: laser power 2000W, scanning speed 1800mm / min, powder feed rate 2.4g / min, argon flow rate 12L / min, overlap rate 66.7%, and spot diameter 3mm.

[0039] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0040] Example 1

[0041] Select pure Ti powder with a particle size of 53–105 μm, nickel-coated graphite powder (20% C, 80% Ni) with a particle size of 15–45 μm, and iron-based alloy powder with a particle size of 75–105 μm. Weigh the above powders according to the following mass ratio: 5% nickel-coated graphite, 4% pure Ti, 91% Fe55 (17.05% Cr, 3.5% B, 3.5% Si, 10% Ni, 0.77% C, and balance iron). After mixing, place the powder mixture in a ball mill jar, add anhydrous ethanol to two-thirds of the jar, and stir in an ultrasonic stirrer for 30 minutes to prepare a powder slurry. Add grinding balls at a ball-to-powder ratio of 3:2, then seal the ball mill jar and mechanically ball mill it in a planetary ball mill at 180 rpm for 30 minutes. After ball milling, place it under a vacuum of less than 10°C. -2 -10 -4 Dry in a vacuum drying oven at 2000 Pa for 2–3 hours; after drying, separate the stainless steel balls and powder using a stainless steel sieve to obtain a uniform mixed powder. Using the method described above, clean the 42CrMo steel substrate with acetone to remove surface oil and other impurities, then ultrasonically clean with anhydrous ethanol for 10 minutes, and blow dry for later use.

[0042] The composite powder and initial Fe55 alloy powder prepared above were clad using an RFC-C6000X fiber laser melting deposition system. Under an argon protective atmosphere, a 6 kW fiber laser was used to prepare the cladding coating on a 42CrMo steel plate with dimensions of 80 mm × 50 mm × 12 mm. The process parameters were: laser power 2000 W, scanning speed 1800 mm / min, powder feed rate 2.4 g / min, argon flow rate 12 L / min, overlap ratio 66.7%, and spot diameter 3 mm.

[0043] Example 2

[0044] In this embodiment, an in-situ TiC / Fe55 metal-based ceramic composite coating is prepared on the surface of a 42CrMo steel plate using an RFC-C6000X fiber laser. The difference from Example 1 is as follows:

[0045] Select pure Ti powder with a particle size of 53–105 μm, nickel-coated graphite powder with a particle size of 15–45 μm (composition: 20% C, 80% Ni), and iron-based alloy powder with a particle size of 75–105 μm. Weigh the above powders according to the following mass ratio: 10% nickel-coated graphite, 8% pure Ti, 82% Fe55 (17.05% Cr, 3.5% B, 3.5% Si, 10% Ni, 0.77% C, and balance iron).

[0046] Example 3

[0047] In this embodiment, an in-situ TiC / Fe55 metal-based ceramic composite coating is prepared on the surface of a 42CrMo steel plate using an RFC-C6000X fiber laser. The difference from Example 1 is as follows:

[0048] Select pure Ti powder with a particle size of 53–105 μm, nickel-coated graphite powder with a particle size of 15–45 μm (composition: 20% C, 80% Ni), and iron-based alloy powder with a particle size of 75–105 μm. Weigh the above powders according to the following mass ratio: 15% nickel-coated graphite, 12% pure Ti, 73% Fe55 (17.05% Cr, 3.5% B, 3.5% Si, 10% Ni, 0.77% C, and balance iron).

[0049] Comparative Example 1

[0050] In this embodiment, an Fe55 metal-based ceramic composite coating is prepared on the surface of a 42CrMo steel plate using an RFC-C6000X fiber laser. The difference from Example 1 is as follows:

[0051] Select iron-based alloy powders with a diameter of 75–105 μm and place them under a vacuum of less than 10 μm. -2 -10 -4 The alloy powder was dried in a vacuum drying oven at a concentration of Pa% for 2–3 hours to obtain a dry alloy powder.

[0052] Compared to Examples 1-3, Comparative Example 1 powder contains only Fe55 alloy and does not contain nickel-coated graphite or pure titanium.

[0053] Comparative Example 2

[0054] In this embodiment, an external nano-TiC / Fe55 metal-based ceramic composite coating is prepared on the surface of a 42CrMo steel plate using an RFC-C6000X fiber laser. The difference from Example 1 is as follows:

[0055] Select nano-TiC powder with a particle size of 40 nm and iron-based alloy powder with a particle size of 75–105 μm. Weigh the above powders according to the following mass ratio: 10% nano-TiC powder, 90% Fe55 (17.05% Cr, 3.5% B, 3.5% Si, 10% Ni, 0.77% C and balance iron).

[0056] Test methods

[0057] The microhardness and wear resistance of the coatings prepared in the examples and comparative examples were tested. The phase composition, microstructure, and wear surface morphology of some coatings were also tested. Among them:

[0058] The microhardness testing method is as follows: a Vickers microhardness tester is used, with a normal load of 500g and a loading time of 15 seconds. The microhardness of the coating area is tested at 100μm intervals. Finally, the average hardness value of 10 random coating areas is taken as the microhardness (HV) of each formulation coating. 0.5 ).

[0059] The wear resistance test method is as follows: A ball-and-disc friction and wear tester is used, employing Al2O3 balls with a diameter of 10 mm. Rotary dry friction tests are conducted on the original iron-based coating and the modified coating under the same friction parameters: normal load 20 N, friction radius 8 mm, friction time 1 hour. The wear volume (mm²) is recorded. 2 ).

[0060] The coating prepared by the method in Example 2 was tested using XRD, and its phase composition is as follows: Figure 1 As shown, the presence of the TiC phase in the deposited layer indicates that pure titanium and nickel-coated graphite successfully underwent an in-situ reaction in the laser-melted pool to produce the TiC-reinforced phase.

[0061] The microstructure of the coating prepared by the method in Example 2 was observed under SEM and TEM microscopes, as shown in Figures 2(a), 3(a), and 3(b), respectively. It can be seen that the prepared TiC / Fe-based cermet composite coating is dense, metallurgically bonded to the substrate, and has a thickness of approximately 0.8 mm. TiC particles with an average particle size of 0.8 µm are uniformly distributed within the coating, and the interface is pure and free of contamination.

[0062] Table 1. Microhardness and wear volume of each test sample

[0063] Test sample <![CDATA[Microhardness (HV 0.5 )]]> <![CDATA[Wear volume (mm 2 )]]> Example 1 Coating 708 0.196 Example 2 Coating 632 0.110 Example 3 Coating 591 0.279 Comparative Example 1 Coating 686 0.486 Comparative Example 2 Coating 602 0.201

[0064] Table 1 shows the microhardness and wear volume of Examples 1-3 and Comparative Examples 1-2. It can be seen that the microhardness of the coatings prepared in the examples of the present invention is not significantly different, ranging from 591 to 708 HV. 0.5With increasing amounts of pure titanium and nickel-coated graphite, the microhardness of the composite deposition layer tends to decrease. In Examples 1-3, the in-situ generation of TiC from pure titanium and nickel-coated graphite in the laser molten pool allows it to act as a wear-resistant reinforcing phase in the coating, significantly improving the wear resistance of the Fe55 iron-based alloy coating. Among them, the TiC / Fe-based composite coating prepared by the method in Example 2 showed a 77.4% reduction in wear volume compared to the initial Fe55 coating, exhibiting superior wear resistance compared to other test samples. In particular, as shown in Figures 2(a)–(b) and Table 1, compared to the iron-based coating with directly added 10 wt.% nano-TiC, the TiC / Fe-based composite coating prepared by the method in Example 2 exhibits superior microhardness and wear resistance due to its higher content of ultrafine TiC particles. Furthermore, the coating prepared by the method in Example 2 was observed using SEM, as shown in Figures 4(a), 4(b), and 4(c). The in-situ TiC particles within the coating pinned the surrounding metal, preventing it from being sheared and peeled off by the grinding balls, and simultaneously hindered crack propagation by "deflecting" the cracks. Therefore, the in-situ TiC particles act as a wear-resistant skeleton and inhibit cracking within the coating, and hold promise for application in the remanufacturing and repair of surface wear damage in key components such as the main bearing sealing runway and cutterhead of tunnel boring machines.

[0065] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of them. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention. Although the specific embodiments of the present invention have been described above, they are not intended to limit the protection scope of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. An in-situ TiC / Fe-based cermet composite wear-resistant powder, characterized in that, It is made by mechanical ball milling and mixing of nickel-coated graphite powder, pure Ti powder and Fe55 alloy powder; the mass fraction of nickel-coated graphite powder is 5%–15%, the mass fraction of pure Ti powder is 4%–12%, and the mass fraction of Fe55 alloy powder is 73%–91%, and the sum of the mass percentages of each component is 100%; and the mass fraction ratio of pure Ti powder to nickel-coated graphite powder is 4:

5. The nickel-coated graphite powder is a coated powder composed of 20% graphite and 80% Ni alloy, wherein the graphite is coated with a layer of nickel metal. The nickel metal coated on the graphite surface has a similar melting point to Fe55 alloy powder; The Fe55 alloy powder is a spherical iron-based self-fluxing alloy composed of 16%–18% Cr, 3.5%–4% B, 3%–4% Si, 10%–13% Ni, 0.7%–1.0% C and the balance iron.

2. The in-situ TiC / Fe-based cermet composite wear-resistant powder as described in claim 1, characterized in that, The particle sizes of the pure Ti powder are 53–105 μm.

3. The in-situ TiC / Fe-based metal-ceramic composite wear-resistant powder as described in claim 1, characterized in that, The particle size of the nickel-coated graphite powder is 15–45 μm.

4. The in-situ TiC / Fe-based cermet composite wear-resistant powder as described in claim 1, characterized in that, The Fe55 alloy powder has a particle size of 75–105 μm.

5. A laser melting deposition method for preparing a TiC / Fe-based composite wear-resistant coating, characterized in that: Includes the following steps: Step 1: Mix nickel-coated graphite powder, pure Ti powder, and Fe55 alloy powder evenly, wet ball mill, and dry to obtain TiC / Fe-based composite powder; wherein the mass fraction of nickel-coated graphite powder is 5%–15%, the mass fraction of pure Ti powder is 4%–12%, and the mass fraction of Fe55 alloy powder is 73%–91%, and the sum of the mass percentages of each component is 100%; and the mass fraction ratio of pure Ti powder to nickel-coated graphite powder is 4:5; Step 2: Process the surface of the part to obtain the pre-processed part; Step 3: The TiC / Fe-based composite powder obtained in Step 1 is clad onto the surface of the pretreated part using laser melting deposition method to form a TiC / Fe-based wear-resistant coating, which contains in-situ submicron TiC hard phase particles. The nickel-coated graphite powder is a coated powder composed of 20% graphite and 80% Ni alloy, wherein the graphite is coated with a layer of nickel metal. The nickel metal coated on the graphite surface has a similar melting point to Fe55 alloy powder; The Fe55 alloy powder is a spherical iron-based self-fluxing alloy composed of 16%–18% Cr, 3.5%–4% B, 3%–4% Si, 10%–13% Ni, 0.7%–1.0% C and the balance iron.

6. The laser melting deposition method for preparing a TiC / Fe-based composite wear-resistant coating as described in claim 5, characterized in that: In-situ submicron TiC hard phase particles are uniformly distributed in the coated metal matrix.

7. An in-situ TiC / Fe-based cermet composite wear-resistant coating, characterized in that, It is prepared by any of the preparation methods described in claims 5-6.

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