Aging treatment in-situ reinforced metal ceramic composite coating as well as preparation method and application thereof

Abstract

The invention provides an aging treatment in-situ reinforced metal ceramic composite coating and a preparation method and application thereof. The preparation method comprises the following working procedures that metal powder and ternary layered metal ceramic MAX phase powder are mixed to obtain mixed powder; spraying the mixed powder on the surface of a workpiece matrix to obtain a precursor coating; and aging treatment is conducted on the precursor coating, and the metal ceramic composite coating is obtained. The aging treatment is carried out in an oxygen-containing atmosphere. According to the metal ceramic composite coating component design and the preparation process, nanoscale ceramic particles can be generated in an in-situ oxidation strengthening mode, compared with the mode that hard ceramic is directly added into the coating, better interface bonding is formed between the ceramic particles generated in situ and metal, the performance is stable, higher hardness is achieved, and the service life of the coating is prolonged. And on the premise that the toughness of the coating is not influenced, the high temperature resistance and the wear resistance of the metal ceramic composite coating can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cermets and their composite materials, specifically to high-temperature wear-resistant cermet composite coatings, and particularly to an aging treatment in-situ strengthened cermet composite coating, its preparation method and application. Background Art

[0002] Cermet composite coatings have excellent properties. The metals in the coatings provide excellent mechanical strength and toughness, and ceramic particles can improve the hardness, wear resistance and corrosion resistance of materials. They are widely used in the surface protection of important components in aerospace, energy, automotive manufacturing and other fields. However, in practical applications, poor interfacial wettability or insufficient bonding force between metal and ceramic materials may still lead to interface weakening, especially under the conditions of external force or temperature change.

[0003] CN115537783A discloses a preparation process of a laser-strengthened coating on a metal surface, including secondary deposition treatment on the surface of a metal substrate to wrap chromium tungsten oxide with nano-silicon, and during the deposition treatment, three times of laser strengthening are supplemented to form a pinning layer on the surface of the metal substrate. At the same time, nano-silicon and chromium tungsten oxide form an alternating layered structure, making the three combine tightly, enhancing the wear resistance effect of the coating. And during the third laser treatment, ammonia water spraying is assisted to form a dense, uniform and self-lubricating coating, enhancing the wear resistance performance; then it is modified with KH-550, 4-ethoxybenzene-1,2-diamine, 2-amino-4-methylpyridine-5-carboxylic acid, 2,2-difluoro-cyclopropanecarbaldehyde to form a corrosion shielding layer. The coating prepared by this patent has the effects of wear resistance and corrosion resistance.

[0004] CN111593291A discloses a preparation method of a cermet high-temperature oxidation-resistant composite coating, including preparing a silane hydrolysis solution, preparing a silica sol-type coating, mixing the silica sol with metal-chromium-aluminum-yttrium alloy powder to make a coating containing metal-chromium-aluminum-yttrium alloy powder, and spraying and curing it into a bottom coating; making a coating containing metal oxide by mixing the silica sol coating or silica sol with metal oxide, and curing the surface coating and other steps. The present invention has good high-temperature oxidation resistance, high strength and good process performance. It realizes low-temperature curing and high-temperature application, meeting the thermal process requirements of a powder superalloy substrate.

[0005] CN114107873A discloses a gradient cermet composite coating and a preparation method thereof. The gradient cermet composite coating on the substrate surface successively includes a transition layer, an inner layer, an intermediate layer and an outer layer; the transition layer is TiAl alloy powder, the inner layer is formed by spraying a composite powder composed of TiAl powder, Al2O3 powder and TiO2 powder, and the intermediate layer is formed by alternately spraying nano-ceramic powder and micro-ceramic powder; the outer layer is Al2O3 powder. In the intermediate layer of this patent, the repeated alternation of nano-particles and micro-particles forms a micro-nano gradient structure, and the nano-particles are used to fill the pores between the micro-particles, reduce the shedding of the micro-particles, and increase the bonding force between the particles.

[0006] In the prior art, in order to obtain better interfacial bonding, it is often necessary to set the composite coating to a complex structure or modify the surface of the ceramic material to improve the bonding of each phase in the composite coating and thus improve the internal polymerization strength. The process is relatively complex, the cost is high, and there is also a risk of introducing impurity phases into the coating.

[0007] Therefore, it is of great significance to provide a cermet composite coating with a simple process, good overall density, high internal polymerization strength, and excellent tribological and mechanical properties. Summary of the Invention

[0008] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an aging treatment in-situ strengthening cermet composite coating, its preparation method and application. By designing the components and preparation process of the cermet composite coating, good interfacial bonding can be formed directly by spraying, without additional surface modification of the ceramic material, and without setting a complex coating structure, the high-temperature resistance and wear resistance of the cermet composite coating can be improved. And the present invention introduces ternary layered metal ceramic MAX phase powder into the raw materials of the cermet composite coating, and combines the aging treatment process. High-temperature induction in-situ oxidation strengthening of the metastable ternary layered metal ceramic MAX phase generates nano-scale ceramic particles. Compared with the pre-doped ceramic particles, the in-situ generated nano-ceramic particles can significantly improve the overall density, internal polymerization strength, tribological and mechanical properties of the cermet composite coating without affecting the toughness of the coating.

[0009] To achieve the purpose of this invention, the following technical solutions are adopted by the present invention:

[0010] In the first aspect, the present invention provides a preparation method of an aging treatment in-situ strengthening cermet composite coating, and the preparation method includes:

[0011] Mixing metal powder and ternary layered metal ceramic MAX phase powder to obtain a mixed powder; spraying the mixed powder on the surface of the workpiece substrate to obtain a precursor coating; performing aging treatment on the precursor coating to obtain the cermet composite coating;

[0012] The aging treatment is carried out in an oxygen-containing atmosphere.

[0013] In the present invention, the oxygen-containing atmosphere includes air and / or an oxygen-containing mixed gas.

[0014] In the present invention, ternary layered metal ceramic MAX phase powder is introduced into the cermet composite coating. Combining with the aging treatment process, the M-site element and the A-site element in the metastable ternary layered metal ceramic MAX phase are in-situ oxidized and strengthened to generate nano-scale ceramic particles at high temperature. Compared with directly adding hard ceramics into the coating, the in-situ generated ceramic particles form a better interfacial bond with the metal, there is no obvious interface, and when subjected to external forces or temperature changes, the interface weakening is not obvious, the performance is stable, and it has a higher hardness. Without affecting the toughness of the coating, it can significantly improve the mechanical and tribological properties of the cermet composite coating. At the same time, the in-situ generated hard ceramics can also partially fill and lap the inherent defects caused by the spraying process technology, such as micropores and cracks, so that the prepared cermet composite coating has higher densification.

[0015] In the present invention, the proportion of the ternary layered metal ceramic MAX phase powder in the mixed powder affects the mechanical properties and microstructure of the cermet composite coating. If the proportion of the ternary layered metal ceramic MAX phase powder is too high, that is, there is too much ternary layered metal ceramic MAX phase in the precursor coating, it will lead to a lower hardness and more defects in the cermet composite coating, and due to its irregular shape, it is difficult to feed the powder during the preparation process.

[0016] Preferably, in the mixed powder, the mass ratio of the metal powder to the ternary layered metal ceramic MAX phase powder is 1:(0.15 - 0.35), for example, it can be 1:0.15, 1:0.17, 1:0.19, 1:0.21, 1:0.23, 1:0.25, 1:0.27, 1:0.29, 1:0.31, 1:0.33 or 1:0.35, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0017] In the present invention, if the average particle size of the metal powder is too small, serious oxidation ablation will occur during the spraying process. If the average particle size of the metal powder is too large, the melting degree of the powder during the spraying process is insufficient, the powder overlapping quality is poor, and it is difficult to form a dense cermet composite coating.

[0018] Preferably, the average particle size of the metal powder is 15μm - 45μm, for example, it can be 15μm, 20μm, 25μm, 30μm, 35μm, 40μm or 45μm, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0019] Preferably, the metal powder includes any one or an alloy powder of at least two of nickel powder, chromium powder, molybdenum powder, tungsten powder, niobium powder, and tantalum powder in any proportion. Preferably, the alloy powder includes Ni 20 Cr, Ni 35 Cr, NiCr, Ni 75 Cr, Ni 80 Cr, Mo 60 W, Mo 25 W, Mo 10 W, Ta 90 Nb, Ta 75 Nb or Ta 60 Any one or a combination of at least two of Nb, including but not limited to typical combinations of Ni 20 Cr and Ni 35 Combination of Cr, NiCr and Ni 75 Combination of Cr, Ni 80 Cr and Mo 60 Combination of W, Mo 25 W and Mo 10 Combination of W, Ta 90 Nb and Ta 75 Combination of Nb, or Ta 60 Combination of Nb and Ni 20 Combination of Cr.

[0020] Preferably, the average particle size of the ternary layered metal ceramic MAX phase powder is 15μm - 45μm, which can effectively ensure the formation of a dense metal ceramic composite coating. The average particle size of the ternary layered metal ceramic MAX phase powder can be, for example, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm or 45μm, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0021] Preferably, the A-site element of the ternary layered metal ceramic MAX phase is Al.

[0022] Preferably, the ternary layered metal ceramic MAX phase powder includes any one or a combination of at least two of Cr2AlC powder, Ti2AlC powder, Sc2AlC powder or V2AlC powder. Typical but non-limiting combinations include combinations of Cr2AlC powder and Ti2AlC powder, Sc2AlC powder and V2AlC powder, V2AlC powder and Cr2AlC powder, or Ti2AlC powder and Sc2AlC powder.

[0023] Preferably, the aging treatment is carried out in an oxygen-containing atmosphere, which includes O2 and an inert atmosphere, where the volume percentage of O2 is 15 vol% - 30 vol%, for example, it can be 15 vol%, 17 vol%, 19 vol%, 21 vol%, 23 vol%, 25 vol%, 27 vol%, 29 vol% or 30 vol%, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable. The inert atmosphere includes N2 and / or inert gas.

[0024] In the present invention, the precursor coating is subjected to aging treatment in an oxygen-containing atmosphere to induce the in-situ spontaneous oxidation of the ternary layered metal ceramic MAX phase to generate nano-sized ceramic particles, strengthen the cermet composite coating, and improve the internal polymerization bonding strength and hardness of the cermet composite coating.

[0025] In the present invention, the aging treatment is carried out at a high temperature to induce the in-situ oxidation of the ternary layered metal ceramic MAX phase in a high-temperature oxygen-containing atmosphere to strengthen the cermet composite coating and improve the internal polymerization bonding strength and hardness of the cermet composite coating. The temperature of the aging treatment affects the strengthening degree of the cermet composite coating. If the temperature is too low, the degree of in-situ oxidation is insufficient, and it is difficult to effectively improve the performance of the cermet composite coating. If the temperature is too high, the ablation oxidation of the cermet composite coating is more, and the situation of oxidation expansion and peeling may occur.

[0026] Preferably, the temperature of the aging treatment is 900 °C - 1200 °C, for example, it can be 900 °C, 950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C or 1200 °C, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0027] Preferably, the time of the aging treatment is 2 h - 5 h, for example, it can be 2 h, 3 h, 4 h or 5 h, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0028] After the aging treatment in the present invention, the workpiece is cooled to room temperature with the furnace.

[0029] Preferably, the thickness of the precursor coating is 250 μm - 300 μm, for example, it can be 250 μm, 255 μm, 260 μm, 265 μm, 270 μm, 275 μm, 280 μm, 285 μm, 290 μm, 295 μm or 300 μm, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0030] Preferably, before the aging treatment of the workpiece sprayed with the precursor coating, grinding and polishing are also included on the surface of the precursor coating.

[0031] In the present invention, the purpose of grinding and polishing the surface of the precursor coating is to remove the relatively rough oxide layer on the surface of the precursor coating and facilitate the diffusion of oxygen in the precursor coating, so as to realize the in-situ oxidation strengthening of the metal-ceramic composite coating by the high-temperature-induced ternary layered metal-ceramic MAX phase in a high-temperature oxygen-containing atmosphere during the subsequent aging treatment, and improve the internal polymerization bonding strength and hardness of the metal-ceramic composite coating.

[0032] Preferably, after the aging treatment, the thickness of the metal-ceramic composite coating is 240 μm - 290 μm, for example, it can be 240 μm, 245 μm, 250 μm, 255 μm, 265 μm, 270 μm, 275 μm, 280 μm, 285 μm or 290 μm, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0033] Preferably, the method of mixing the mixed metal powder and the ternary layered metal-ceramic MAX phase powder includes mechanical stirring or ball milling.

[0034] In the present invention, the process parameters of mechanical stirring or ball milling are aimed at realizing the mixing of the metal powder and the ternary layered metal-ceramic MAX phase powder, and are not particularly limited.

[0035] For example, the rotation speed of mechanical stirring can be 100 rpm - 250 rpm, for example, it can be 100 rpm, 120 rpm, 140 rpm, 160 rpm, 180 rpm, 200 rpm, 225 rpm or 250 rpm, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0036] For example, the ball-to-material ratio of ball milling can be (2 - 8):1, for example, it can be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1 or 8:1, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0037] Preferably, the spraying method includes supersonic plasma spraying.

[0038] In the present invention, the precursor coating is prepared on the surface of the workpiece substrate by supersonic plasma spraying, which is beneficial to improving the densification of the precursor coating and further improving the densification of the metal-ceramic composite coating. The present invention does not particularly limit the equipment for supersonic plasma spraying. Exemplarily, the supersonic plasma spraying equipment used in the present invention is the HEPJet supersonic plasma spraying device system independently developed by the Army Academy of Armored Forces.

[0039] Preferably, before spraying the surface of the workpiece substrate, the preparation method provided by the present invention further includes sandblasting the surface of the workpiece substrate. The sand used for the sandblasting can be any one or a combination of at least two of brown fused alumina sand, copper ore sand, or steel sand. After sandblasting, the color of the surface of the metal substrate is required to be uniform everywhere, without uneven areas visible to the naked eye. After sandblasting is completed, the surface is blown with clean compressed air to ensure that there are no residual sand grains, and the residual stains or dust are removed by wiping with alcohol. The sandblasting equipment used is the commonly used equipment in the art.

[0040] Preferably, the current of the supersonic plasma spraying is 400A - 500A, for example, it can be 400A, 410A, 420A, 430A, 440A, 450A, 460A, 470A, 480A, 490A, or 500A, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0041] Preferably, the voltage of the supersonic plasma spraying is 90V - 120V, for example, it can be 90V, 95V, 100V, 105V, 110V, 115V, or 120V, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0042] Preferably, the main gas of the supersonic plasma spraying is Ar, and the main gas flow rate is 100L / min - 150L / min, for example, it can be 100L / min, 110L / min, 120L / min, 130L / min, 140L / min, or 150L / min, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0043] Preferably, the secondary gas of the supersonic plasma spraying is H2, and the secondary gas flow rate is 10L / min - 40L / min, for example, it can be 10L / min, 15L / min, 20L / min, 25L / min, 30L / min, 35L / min, or 40L / min, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0044] Preferably, the distance between the spray gun of the supersonic plasma spraying and the surface of the workpiece substrate is 80mm - 120mm, for example, it can be 80mm, 85mm, 90mm, 95mm, or 100mm, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0045] Preferably, the powder feeding amount of the supersonic plasma spraying is 3 g / min - 10 g / min. For example, it can be 3 g / min, 4 g / min, 5 g / min, 6 g / min, 7 g / min, 8 g / min, 9 g / min or 10 g / min, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0046] Preferably, during the supersonic plasma spraying, compressed cooling air is used to cool the precursor coating on the back of the substrate.

[0047] In a second aspect, the present invention provides a cermet composite coating, and the composite coating is prepared by the preparation method as described in the first aspect.

[0048] In a third aspect, the present invention provides an application of the composite coating as described in the second aspect, and the composite coating is applied to the field of workpiece surface protection.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) By designing the components and preparation process of the cermet composite coating, the present invention can directly form a good interfacial bond during spraying, without the need for additional surface modification of ceramic materials or the setting of complex coating structures, thus improving the high-temperature resistance and wear resistance of the cermet composite coating.

[0051] (2) By introducing ternary layered metal ceramic MAX phase powder into the raw materials of the cermet composite coating and combining with the aging treatment process, the present invention can in-situ oxidize and strengthen the metastable ternary layered metal ceramic MAX phase at high temperature to generate nano-scale ceramic particles, significantly improving the overall density, internal polymerization strength, tribological and mechanical properties of the cermet composite coating. Description of the Drawings

[0052] Figure 1 It is the SEM image of the Cr2AlC ternary layered metal ceramic MAX phase powder in Example 1.

[0053] Figure 2 It is the SEM image of the Ni 20 Cr alloy powder in Example 1.

[0054] Figure 3 It is the SEM image of the cross-section of the cermet composite coating prepared in Example 1.

[0055] Figure 4 It is the element distribution of the nano-scale ceramic phase in-situ oxidized from the Cr2AlC ternary layered metal ceramic MAX phase in the cermet composite coating prepared in Example 1.

[0056] Figure 5 It is the SEM image of the cross-section of the cermet composite coating prepared in Comparative Example 1. Specific Embodiments

[0057] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0058] Example 1

[0059] This example provides a method for preparing a cermet composite coating, and the preparation method includes:

[0060] (1) At a rotation speed of 150 rpm, mechanically stir and mix Ni 20 Cr alloy powder and ternary layered cermet MAX phase powder with the composition of Cr2AlC to obtain a mixed powder. Among them, the average particle size of Ni 20 Cr alloy powder is 20 μm, and the average particle size of Cr2AlC ternary layered cermet MAX phase powder is 30 μm.

[0061] (2) Use brown fused alumina sand to perform sandblasting treatment on the surface of the workpiece, and then spray the mixed powder in step (1) onto the surface of the workpiece substrate by supersonic plasma spraying to obtain a precursor coating. During spraying, compressed air is used to cool the precursor coating on the back of the workpiece substrate. After spraying, a micrometer is used to measure the thickness of the precursor coating to be 274 μm. The process parameters of supersonic plasma spraying are shown in Table 1.

[0062] Table 1 Supersonic Plasma Spraying Parameters of Example 1

[0063]

[0064] (3) After the spraying in step (2) is completed, grind and polish the precursor coating to remove the relatively rough oxide layer on the surface, and then perform aging treatment in an air atmosphere. The temperature of the aging treatment is 1000 °C and the time is 2 h to prepare a cermet composite coating.

[0065] The SEM image of the Cr2AlC ternary layered cermet MAX phase powder used in the preparation process of this example is as Figure 1 shown, the SEM image of Ni 20 Cr alloy powder is as Figure 2 shown, the thickness of the prepared cermet composite coating is 267 μm, and the cross-section SEM image is as Figure 3 shown. In the cermet composite coating, the element distribution of the nano-scale ceramic phase in-situ oxidized from the Cr2AlC ternary layered cermet MAX phase is as Figure 4as shown

[0066] Example 2

[0067] This example provides a method for preparing a cermet composite coating, and the preparation method includes:

[0068] (1) At a rotation speed of 200 rpm, mechanically stir and mix Ni 20 Cr alloy powder and ternary layered cermet MAX phase powder with the composition of Cr2AlC to obtain a mixed powder. Among them, the average particle size of the Ni 20 Cr alloy powder is 15 μm, and the average particle size of the Cr2AlC ternary layered cermet MAX phase powder is 17 μm.

[0069] (2) Use brown fused alumina sand to perform sandblasting treatment on the surface of the workpiece, and then spray the mixed powder in step (1) onto the surface of the workpiece substrate by supersonic plasma spraying to obtain a precursor coating. During spraying, compressed air is used to cool the precursor coating on the back of the workpiece substrate. After spraying, a micrometer is used to measure the thickness of the precursor coating to be 255 μm. The process parameters of supersonic plasma spraying are shown in Table 2.

[0070] Table 2 Supersonic Plasma Spraying Parameters for Example 2

[0071]

[0072] (3) After the spraying in step (2) is completed, grind and polish the precursor coating to remove the relatively rough oxide layer on the surface, and then perform aging treatment in an oxygen-containing atmosphere with an O2 volume percentage of 15 vol%, the aging treatment temperature is 900 °C, and the time is 5 h to prepare a cermet composite coating.

[0073] The thickness of the cermet composite coating prepared in this example is 243 μm.

[0074] Example 3

[0075] This example provides a method for preparing a cermet composite coating, and the preparation method includes:

[0076] (1) With a ball-to-material ratio of 5:1, ball-mill and mix TaNb alloy powder and ternary layered cermet MAX phase powder with the composition of Ti2AlC to obtain a mixed powder. Among them, the average particle size of the TaNb alloy powder is 44 μm, and the average particle size of the Ti2AlC ternary layered cermet MAX phase powder is 45 μm.

[0077] (2) The surface of the workpiece is sandblasted with brown fused alumina, and then the mixed powder in step (1) is sprayed onto the surface of the workpiece substrate by supersonic plasma spraying to obtain a precursor coating. During spraying, compressed air is used to cool the precursor coating on the back of the workpiece substrate. After spraying, a micrometer is used to measure the thickness of the precursor coating, which is 295 μm. The process parameters of supersonic plasma spraying are shown in Table 3.

[0078] Table 3 Parameters of supersonic plasma spraying in Example 3

[0079]

[0080] (3) After the spraying in step (2) is completed, the precursor coating is ground and polished to remove the relatively rough oxide layer on the surface, and then solution treatment is carried out in an oxygen-containing atmosphere with an O2 volume percentage of 30 vol%, the temperature of the solution treatment is 1200 °C, and the time is 2 h to prepare a cermet composite coating.

[0081] The thickness of the cermet composite coating prepared in this example is 289 μm.

[0082] Example 4

[0083] This example provides a method for preparing a cermet composite coating. Except that in the mixed powder in step (1), the mass ratio of Ni 20 Cr alloy powder to Cr2AlC ternary layered metal ceramic MAX phase powder is 1:0.05, the rest are the same as in Example 1.

[0084] The thickness of the cermet composite coating prepared in this example is 264 μm.

[0085] Example 5

[0086] This example provides a method for preparing a cermet composite coating. Except that in the mixed powder in step (1), the mass ratio of Ni 20 Cr alloy powder to Cr2AlC ternary layered metal ceramic MAX phase powder is 1:0.45, the rest are the same as in Example 1.

[0087] The thickness of the cermet composite coating prepared in this example is 268 μm.

[0088] Example 6

[0089] This example provides a method for preparing a cermet composite coating. Except that in the mixed powder in step (1), the particle size of Ni 20 Cr alloy powder is 10 μm, the rest are the same as in Example 1.

[0090] The thickness of the cermet composite coating prepared in this example is 266 μm.

[0091] Example 7

[0092] This example provides a method for preparing a cermet composite coating. Except that the particle size of the Ni 20 Cr alloy powder in the mixed powder in step (1) is 60 μm, the rest are the same as in Example 1.

[0093] The thickness of the cermet composite coating prepared in this example is 265 μm.

[0094] Example 8

[0095] This example provides a method for preparing a cermet composite coating. Except that the particle size of the Cr2AlC ternary layered metal ceramic MAX phase powder in the mixed powder in step (1) is 10 μm, the rest are the same as in Example 1.

[0096] The thickness of the cermet composite coating prepared in this example is 264 μm.

[0097] Example 9

[0098] This example provides a method for preparing a cermet composite coating. Except that the particle size of the Cr2AlC ternary layered metal ceramic MAX phase powder in the mixed powder in step (1) is 60 μm, the rest are the same as in Example 1.

[0099] The thickness of the cermet composite coating prepared in this example is 268 μm.

[0100] Example 10

[0101] This example provides a method for preparing a cermet composite coating. Except that the aging treatment temperature of the mixed powder in step (3) is 700 °C, the rest are the same as in Example 1.

[0102] The thickness of the cermet composite coating prepared in this example is 266 μm.

[0103] Example 11

[0104] This example provides a method for preparing a cermet composite coating. Except that the aging treatment temperature of the mixed powder in step (3) is 1500 °C, the rest are the same as in Example 1.

[0105] The thickness of the cermet composite coating prepared in this example is 271 μm.

[0106] Example 12

[0107] This embodiment provides a method for preparing a cermet composite coating. Except that step (3) is carried out in an oxygen-containing atmosphere with an O2 volume concentration of 5 vol%, the rest are the same as those in Embodiment 1.

[0108] The thickness of the cermet composite coating prepared in this embodiment is 265 μm.

[0109] Embodiment 13

[0110] This embodiment provides a method for preparing a cermet composite coating. Except that step (3) is carried out in an oxygen-containing atmosphere with an O2 volume concentration of 50 vol%, the rest are the same as those in Embodiment 1.

[0111] The thickness of the cermet composite coating prepared in this embodiment is 273 μm.

[0112] Comparative Example 1

[0113] This comparative example provides a method for preparing a cermet composite coating. Except that step (3) is not carried out, that is, aging treatment is not carried out, the rest are the same as those in Embodiment 1.

[0114] The thickness of the cermet composite coating prepared in this comparative example is 271 μm. The SEM of the cross-section of the prepared cermet composite coating is as Figure 5 shown.

[0115] Comparative Example 2

[0116] This comparative example provides a method for preparing a cermet composite coating. Except that step (3) is carried out in an Ar environment, that is, in an oxygen-free environment, the rest are the same as those in Embodiment 1.

[0117] The thickness of the cermet composite coating prepared in this comparative example is 271 μm.

[0118] Comparative Example 3

[0119] This comparative example provides a method for preparing a cermet composite coating. Except that in step (1), the ternary layered metal ceramic MAX phase powder with the composition of Cr2AlC is replaced with equimolar Al2O3 with an average particle size of 60 nm and Cr2O3 with an average particle size of 70 nm, the rest are the same as those in Embodiment 1.

[0120] The thickness of the cermet composite coating prepared in this comparative example is 268 μm.

[0121] Performance test:

[0122] Vickers hardness and friction and wear tests were carried out on the cermet composite coatings prepared in all the above examples and comparative examples.

[0123] The test was carried out using a Vickers hardness instrument with a test load of 0.1 N and a holding time of 15 s.

[0124] The method for the friction and wear test was to use a friction and wear tester to test the tribological properties of the cermet composite coating. The test load was 3 N, the rotational speed was 600 rpm, the rotational diameter was 5 mm, the test time was 30 min, and the counter ball was a Si3N4 ceramic ball with a diameter of 5 mm. The test standard was ASTM G99-17, and a white light interferometer (AMETEK New Vive 9000) was used to measure the wear volume. The calculation formula for the wear rate was as follows: W = V / SL, where V, S, and L represent the wear volume (mm 3 ) sliding distance (m), and applied load (N), respectively.

[0125] The test results are shown in Table 4.

[0126] Table 4

[0127] Vickers hardness / HV0.1 <![CDATA[Friction and Wear Test / 10 -5 .N -1 .m -1 > Example 1 650.3 <![CDATA 1.114 > Example 2 450.3 4.302 Example 3 473.5 2.364 Example 4 482.7 2.147 Example 5 810.2 3.431 Example 6 320.3 6.351 Example 7 614.4 3.657 Example 8 493.7 4.647 Example 9 456.7 4.329 Example 10 483.4 2.647 Example 11 763.4 8.354 Example 12 504.6 2.397 Example 13 794.4 6.871 Comparative Example 1 404.2 4.673 Comparative Example 2 435.1 4.354 Comparative Example 3 643.1 4.532

[0128] In the present invention, by introducing ternary layered metal ceramic MAX phase powder into the raw materials of the cermet composite coating and combining with the aging treatment process, high-temperature induction in-situ oxidation strengthening of the metastable ternary layered metal ceramic MAX phase generates nano-scale ceramic particles. Compared with the pre-doped ceramic particles, the in-situ generated nano-ceramic particles form a better interfacial bond with the metal. Under the action of external forces or in an environment of temperature change, the interface weakening is not obvious, the performance is stable, and it has higher hardness. Without affecting the toughness of the coating, it can significantly improve the overall densification, internal polymerization strength, tribological and mechanical properties of the cermet composite coating. Combining with the adjustment of the process, a good interfacial bond can be formed by direct spraying, without the need for additional surface modification of the ceramic material, nor the need to set up a complex coating structure, and the high-temperature resistance and wear resistance of the cermet composite coating can be improved.

[0129] According to the test results in Table 1, compared with Example 1, not performing the aging treatment in Comparative Example 1 or performing the aging treatment in an Ar atmosphere in Comparative Example 2 will both result in the inability of the M-site element and the A-site element in the ternary layered metal ceramic MAX phase to be in-situ oxidized and strengthened to generate nano-scale ceramic particles, resulting in a significant decrease in the hardness and wear resistance of the prepared cermet composite coating. In Comparative Example 3, even if an equimolar amount of nano-Al2O3 and nano-Cr2O3 is introduced into the cermet composite layer, the technical effects of significantly improving the hardness and wear resistance brought by the in-situ generated Al2O3 and nano-Cr2O3 in Example 1 cannot be achieved.

[0130] Compared with Example 1, in Examples 4 to 5, if the proportion of the ternary layered metal ceramic MAX phase powder in the mixed powder is too high or too low, it will affect the mechanical properties and microstructure of the cermet composite coating, resulting in a decrease in the hardness and wear resistance of the cermet composite coating.

[0131] Compared with Example 1, in Examples 6 to 9, if the average particle size of the metal powder and the ternary layered metal ceramic MAX phase powder is too small, severe oxidation ablation will occur during the spraying process. If the average particle size is too large, the degree of powder melting during the spraying process is insufficient, the powder lap quality is poor, and it is difficult to form a dense cermet composite coating, resulting in a decrease in the hardness and wear resistance of the cermet composite coating.

[0132] According to the data results of Example 1 and Examples 10 to 13, if the aging treatment temperature is too high or too low, or the aging treatment is not carried out in an atmosphere with a specific oxygen concentration defined in the present invention, the internal polymerization bonding strength and hardness of the cermet composite coating cannot be effectively improved, and the improvement of hardness and wear resistance is not ideal.

[0133] The applicant declares that the above description is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A preparation method of an age-hardening in-situ strengthened cermet composite coating, characterized in that, The preparation method includes: Mixing metal powder and ternary layered metal ceramic MAX phase powder to obtain a mixed powder; spraying the mixed powder on the surface of a workpiece substrate to obtain a precursor coating; performing aging treatment on the precursor coating to obtain the in-situ strengthened metal ceramic composite coating after aging treatment; The aging treatment is carried out in an oxygen-containing atmosphere.

2. The preparation method according to claim 1, characterized in that, In the mixed powder, the mass ratio of the metal powder to the ternary layered metal ceramic MAX phase powder is 1:(0.15 - 0.35).

3. The preparation method according to claim 1 or 2, characterized in that, The average particle size of the metal powder is 15μm - 45μm; Preferably, the metal powder includes any one or at least two alloy powders in any proportion among nickel powder, chromium powder, molybdenum powder, tungsten powder, niobium powder, and tantalum powder.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The average particle size of the ternary layered metal ceramic MAX phase powder is 15μm - 45μm; Preferably, the A-site element of the ternary layered metal ceramic MAX phase is Al; Preferably, the ternary layered metal ceramic MAX phase powder includes any one or at least two combinations among Cr2AlC powder, Ti2AlC powder, Sc2AlC powder, or V2AlC powder.

5. The preparation method according to any one of claims 1-4, characterized in that, The oxygen-containing atmosphere includes O2 and an inert atmosphere, where the volume percentage of O2 is 15vol% - 30vol%, and the inert atmosphere includes N2 and / or an inert gas.

6. The preparation method according to any one of claims 1-5, characterized in that, The temperature of the aging treatment is 900°C - 1200°C; Preferably, the time of the aging treatment is 2h - 5h.

7. The preparation method according to any one of claims 1-6, characterized in that, The thickness of the precursor coating is 250μm - 300μm; Preferably, before performing aging treatment on the workpiece after spraying the precursor coating, it further includes grinding and polishing the surface of the precursor coating; Preferably, after the aging treatment is completed, the thickness of the metal ceramic composite coating is 240μm - 290μm.

8. The preparation method according to any one of claims 1-7, characterized in that, The method of mixing the mixed metal powder and the ternary layered metal ceramic MAX phase powder includes mechanical stirring or ball milling; Preferably, the spraying method includes supersonic plasma spraying.

9. A cermet composite coating, characterized in that, The metal ceramic composite coating is prepared by the preparation method according to any one of claims 1 - 8.

10. An application of the cermet composite coating as described in claim 9, characterized in that, The metal ceramic composite coating is applied to the field of workpiece surface protection.

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