High-wear-resistance coating powder and application

Abstract

The invention relates to high-wear-resistance coating powder and application, and belongs to the field of development of a high-temperature-resistant and wear-resistant coating technology. The high-wear-resistance coating powder comprises the following components in percentage by mass: 19%-21% of Ni, 8.5%-11.3% of C, less than or equal to 0.03% of O and the balance of Cr. The high-wear-resistance coating powder is prepared through the following steps that S1, NiCr alloy powder and chromium carbide powder are taken according to the mass ratio of (23.5-26.5): (73.5-76.5), and the NiCr alloy powder and the chromium carbide powder are mixed to be uniform; s2, carrying out spray drying on the proportioned mixed powder in a spray granulation tower by taking alcohol as a solvent, sintering and then crushing; and S3, the mixed powder is subjected to early-stage drying treatment through a drying oven, and the high-wear-resistance coating powder is obtained. The average hardness of a coating of the high-wear-resistance coating powder is 950 HV to 1050 HV, the friction coefficient is 0.35 to 0.5, and the high-wear-resistance coating powder is extremely excellent in temperature and wear resistance.

Description

Technical Field

[0001] The invention relates to high wear-resistant coating powder and application thereof, and belongs to the field of high-temperature-resistant and wear-resistant coating technology development. Background Art

[0002] Unlike a reciprocating engine, where the piston and crankshaft have a 1:1 relationship, a rotary engine's motion involves the center of the triangular rotor revolving around the center of the output shaft while the triangular rotor itself rotates around its own center. The output shaft speed of a rotary engine is three times the rotor's rotational speed. This is because the rotor generates work three times per revolution, resulting in a high horsepower-to-volume ratio. Furthermore, due to its axial rotational nature, high speeds can be achieved without the need for precise crankshaft balancing. Furthermore, with only two rotating parts, a rotary engine significantly simplifies its structure compared to a typical four-stroke engine with over twenty moving parts, such as intake and exhaust valves, and significantly reduces the potential for failure. However, due to the kinematic relationship of the rotary engine, the triangular rotor's apex moves in a figure-eight pattern, resulting in uneven internal stress distribution and the risk of cracking. Furthermore, because a single radial seal exists between adjacent chambers in a triangular rotary engine, and this seal is in constant line contact with the cylinder block, wear between the seal and the cylinder block can easily occur, leading to air leaks and even the appearance of wavy lines (chatter marks) on the rotor chamber's inner wall, compromising engine durability. To address these issues, patent application CN115287580A describes a high-contact fatigue-resistant sealing coating for rotary engine inner cylinders and its preparation method. The coating is prepared using Ni powder, Cr powder, and Cr3C2 powder in a controlled mass ratio of 1:1:(2.5-5) and then applied via supersonic plasma spraying. This technology improves the product's contact fatigue life by introducing Cr3C2 powder and preparing BiCrCr3C2 with an appropriate composition; however, the specific friction performance is not addressed. Summary of the Invention

[0003] The technical problem solved by the present application is to overcome the above-mentioned deficiencies in the prior art and to provide a high wear-resistant coating powder and its application.

[0004] The technical solution employed in this application to solve the aforementioned technical problem includes: a highly wear-resistant coating powder comprising the following components by mass: Ni: 19% to 21%, C: 8.5% to 11.3%, O ≤ 0.03%, and Cr: the balance. The carbon is derived from the Cr3C2 hard phase, providing the coating with high hardness and wear resistance while also improving its thermal stability. The Ni and excess Cr form a solid solution that acts as a binder phase in the coating, enhancing its toughness and crack resistance.

[0005] The technical solution adopted by the present application to solve the above technical problems also includes: the above-mentioned high wear-resistant coating powder can be prepared by the following steps: S1 uses NiCr alloy powder and Cr3C2 powder to prepare a mixed powder; NiCr alloy powder: Cr3C2 powder are mixed in a mass ratio of (23.5% to 26.5%): (73.5% to 76.5%); the mass ratio of Ni to Cr in the NiCr alloy powder is 4:1;

[0006] S2 spray-dries, sinters and crushes the mixed powder in a spray granulation tower using alcohol as a solvent;

[0007] S3 uses an oven to pre-dry the mixed powder to obtain a high-wear-resistant coating powder for the inner cavity of the rotary engine cylinder.

[0008] Preferably, the NiCr alloy powder has a particle size of ≤20 μm.

[0009] Preferably, the particle size of the Cr3C2 powder ranges from 2um to 6um.

[0010] Preferably, step S1 further includes step S11: mixing the prepared mixed powder, silicon nitride grinding balls, deionized water, and polyethylene glycol in a mass ratio of 1:8:3:0.3 for 20 to 36 hours, with the ball mill rotating at a speed of 300 r / min to 350 r / min.

[0011] The sintering is carried out in an inert protective atmosphere at a sintering temperature of 1150° C. to 1250° C.

[0012] After step S2, step S21 is further provided:

[0013] The crushed mixed powder is screened in step S21 to obtain a mixed powder with a particle size ranging from 15 μm to 53 μm, preferably with a particle size ranging from 15 μm to 45 μm.

[0014] The oven temperature is set at 75-85° C. and the drying time is set at 90-150 min.

[0015] The technical solution adopted by this application to solve the above-mentioned technical problem also includes: an application of a high-wear-resistant coating powder, wherein the application includes preparing the high-wear-resistant coating powder into a wear-resistant coating. When applied in industry, the high-wear-resistant coating powder is applied to the inner cavity of an engine cylinder to form a high-wear-resistant coating, which comprises the following steps:

[0016] A1 installs the engine block to the spraying tooling;

[0017] A2 engine cylinder inner cavity surface sandblasting treatment;

[0018] A3 uses supersonic flame spraying to spray high-wear-resistant coating powder onto the inner surface of the rotating cylinder body through a spray gun, obtaining a preliminary qualified engine cylinder inner cavity coating.

[0019] The application of the high wear-resistant coating powder of the present invention may further include step A4:

[0020] A4 The engine cylinder inner cavity coating that has been preliminarily sprayed and qualified is ground to a coating thickness of 0.15mm±0.01mm by coordinate grinding, with a roughness of ≤0.12um. The thickness of the engine cylinder inner cavity coating that has been preliminarily sprayed and qualified is between 0.3mm and 0.4mm, and the friction coefficient is between 0.35-0.5.

[0021] The engine cylinder block is mounted on a rotating shaft through a spraying tool, and the rotating speed of the rotating shaft is 100 r / min to 180 r / min.

[0022] The surface roughness of the inner cavity surface of the engine cylinder body after sandblasting is 60um to 100um.

[0023] The angle of the spray gun relative to the spraying surface is 50° to 70°.

[0024] During spraying, the oxygen flow rate is 700 L / min to 840 L / min, preferably 775 to 835 L / min, and the kerosene flow rate is 20 L / h to 26 L / h, preferably 24 to 26 L / h.

[0025] The powder feeding amount during spraying is 25g / min~40g / min, and the spray gun moving speed is 5mm / s~10mm / s.

[0026] The spraying distance during spraying is 350mm~400mm.

[0027] To ensure the uniformity of the cylinder coating, it is necessary to control the temperature and rotation direction of the cylinder during the spraying process; the temperature of the inner surface of the cylinder cavity increases significantly during the spraying process, and the outer contour of the cylinder cannot be forced to cool externally to avoid deformation caused by the large temperature difference between the inside and outside of the cylinder; the spray gun must move in a straight line during the spraying process to ensure that the long and short axes of the "8"-shaped cylinder cavity are evenly coated. In order to further improve the uniformity of the coating, considering that there is a certain change in the angle of the left and right sides of the short axis of the cylinder cavity relative to the spray gun, the rotation direction of the cylinder is alternately changed during the spraying process. Any spraying process includes two round trips on the same spraying path, and the rotary engine cylinder rotates in opposite directions during these two trips.

[0028] The thickness of the coating that has passed the preliminary spraying is tested by three coordinates to ensure that the coating thickness is 0.3mm~0.4mm.

[0029] The coating that has passed the initial spraying should be processed again, and the coating thickness should be polished to 0.15mm±0.01mm by coordinate grinding, and the roughness should be ensured to be ≤0.12um.

[0030] The average hardness of the coating that has passed the preliminary spraying is 950HV~1050HV, and the friction coefficient is 0.35-0.5.

[0031] As a further preference, the cylinder body is made of aluminum alloy ZAlSi7Mg.

[0032] The coating obtained on the aluminum substrate of the present invention has a friction coefficient of 0.4-0.47 and a wear rate of 4.2-4.65×10 -5 mm 3 / (N•m). The coating obtained by the present invention has extremely excellent heat-resistant wear performance.

[0033] This application controls the NiCr-CrC powder composition ratio, and then uses supersonic flame spraying to spray high-wear-resistant coating powder inside the rotor engine cylinder cavity onto the surface of the rotor engine cylinder cavity to a predetermined coating thickness. The coating thickness is then tested and coordinate grinding is performed to form the coating, thereby achieving high-temperature and high-speed alternating service of the rotor engine coating and solving the problem of insufficient wear resistance.

[0034] The engine of the present invention includes the rotary engine. As a further preferred embodiment, the cylinder body of the engine is made of aluminum alloy.

[0035] This application has the following beneficial effects:

[0036] 1) The high wear-resistant coating powder prepared by the present invention has uniform composition and good sphericity;

[0037] 2) The preparation process of the high wear-resistant coating for the inner cavity of the engine cylinder of the present invention is simple and convenient, and is easy to mass produce;

[0038] 3) The surface coating of the present invention has relatively uniform thickness and good crack resistance; the organizational structure is relatively dense and has low porosity, and the interface is well bited, which can meet the application requirements of long-term operation sealing and wear resistance under high temperature and high speed conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is an electron microscope image of the NiCr-CrC powder product obtained in Example 1 of the present application; Figure 1 It can be seen that the obtained NiCr-CrC powder has uniform composition and good sphericity.

[0040] Figure 2The microstructure of the coating obtained in Example 1 of the present application; Figure 2 It can be seen that the porosity in the thermal spray coating is low and the interface is well bonded.

[0041] Figure 3 The microstructure of the coating obtained in Comparative Example 3 is shown; Figure 3 It can be seen that the coating thickness is uneven, there are many large voids, and the bonding at the interface is poor. DETAILED DESCRIPTION

[0042] The present application will be further described in detail below with reference to the accompanying drawings and examples. The following examples are intended to explain the present application but the present application is not limited to the following examples.

[0043] The present application discloses a high-wear-resistant coating powder for the inner cavity of a rotary engine cylinder, wherein the weight percentages of the components of the powder are as follows: Ni: 19% to 21%, C: 8.5% to 11.3%, O≤0.03%, and Cr: the remainder.

[0044] The method for preparing the high-wear-resistant coating powder and coating for the inner cavity of the rotary engine cylinder body (the first three steps are the powder preparation method, and the last four steps are the coating preparation method) of the present application comprises the following steps:

[0045] 1) NiCr alloy powder and Cr3C2 powder are mixed in a mass ratio of (23.5% to 26.5%): (73.5% to 76.5%). The mass ratio of Ni to Cr in the NiCr alloy powder is 4:1.

[0046] 2) The mixed powder is spray-dried, sintered, and crushed in a spray granulation tower using alcohol as a solvent to obtain NiCr-CrC powder; the particle size of the NiCr-CrC powder ranges from 15 μm to 53 μm;

[0047] 3) The NiCr-CrC powder is pre-dried in an oven to obtain the coating powder for the inner cavity of the rotary engine cylinder.

[0048] 4) Clamp the aluminum alloy cylinder block of the rotary engine onto the tooling used for spraying;

[0049] 5) Sandblast the inner surface of the aluminum alloy cylinder in step 4;

[0050] 6) Place the assembled aluminum alloy cylinder body tooling on a rotating motor or lathe shaft. Use the powder feeder in the supersonic flame spraying equipment to feed the alloy powder into the spray gun. Set specific spraying parameters and initiate a process of ignition-powder feeding-spraying-cooling-spraying. The NiCr-CrC powder is sprayed onto the inner surface of the cylinder body to form a NiCr-CrC coating. Specifically, to ensure coating quality, the spraying parameters must be strictly controlled.

[0051] 7) The inner cavity of the aluminum alloy cylinder body that has been sprayed and qualified in step 6 is processed to produce a finished cylinder body.

[0052] Specifically, the particle size of the NiCr alloy powder is ≤20 μm, and the particle size range of the Cr3C2 powder is 2 μm to 6 μm; the angle of the spray gun relative to the spray surface is 50° to 70°, the oxygen flow rate is 700 L / min to 850 L / min, and the kerosene flow rate is 20 L / h to 26 L / h; the powder feeding amount is 25 g / min to 40 g / min, the spray gun moving speed is 5 mm / s to 10 mm / s, and the spraying distance is 350 mm to 400 mm; the rotation speed of the rotating shaft is 100 r / min to 180 r / min; and the surface temperature of the sprayed metal is ensured to be 50°C to 120°C during the spraying process;

[0053] In order to ensure the uniformity of the cylinder coating, this application must control the temperature, rotation speed and direction, and spraying distance of the cylinder during the spraying process; the temperature of the inner surface of the cylinder cavity increases significantly during the spraying process, and the outer contour of the cylinder body cannot be externally forced to cool to avoid deformation caused by the large temperature difference between the inside and outside of the cylinder; the spraying process ensures that the spray gun moves in a straight line to ensure that the long axis and short axis of the "8"-shaped cylinder cavity are evenly coated. In order to further improve the uniformity of the coating, considering that there is a certain change in the angle of the left and right sides of the short axis of the cylinder cavity relative to the spray gun, the rotation direction of the cylinder is changed alternately during the spraying process. Any spraying during the spraying process includes two round trips on the same spraying path, and the rotary engine cylinder rotates in opposite directions in these two trips.

[0054] The coating thickness of NiCr-CrC powder is tested by three-coordinate measurement to ensure that the initial coating thickness is 0.3mm~0.4mm; after the NiCr-CrC powder coating meets the initial thickness, it should be processed again and the coating thickness should be polished to 0.15mm±0.01mm by coordinate grinding, and the roughness should be guaranteed to be ≤0.12um.

[0055] Example 1

[0056] In this embodiment, the rotary engine cylinder body is made of aluminum alloy ZAlSi11Cu3 (brand ADC12).

[0057] In this embodiment, the powder for the high wear-resistant coating for the inner cavity of the rotary engine cylinder body is prepared by using NiCr alloy powder with a mass percentage of 4:1 (i.e., in the NiCr alloy powder, the mass ratio is Ni:Cr=4:1) and Cr3C2 powder with a mass percentage ratio of 1:3; the particle sizes of the NiCr alloy powder and Cr3C2 powder with a mass percentage of 4:1 are 20 μm and 6 μm respectively. The specific data of the powder for the high wear-resistant coating for the inner cavity of the rotary engine cylinder body in Example 1 are Ni: 20%, C: 10%, O: 0.0 2%, Cr: balance; the above-mentioned NiCr-CrC powder was used for supersonic flame spraying in the inner cavity of the aluminum alloy cylinder: the particle size range of the NiCr-CrC powder was 15um~45um; the angle of the spray gun relative to the spray surface was 60°, the oxygen flow rate was 780L / min, and the kerosene flow rate was 24L / h; the powder feed rate was 30g / min, the spray gun moving speed was 6mm / s, and the spraying distance was 400mm; the rotation speed of the rotating shaft was 120r / min; the spraying process ensured that the surface temperature of the sprayed metal was 50℃~120℃;

[0058] In this embodiment, the coating thickness is 0.34 mm, and the average hardness of the coating is 982 HV1. After processing, the coating thickness is 0.15 mm and the roughness is 0.11 μm. Under the conditions of silicon nitride as the grinding material (temperature 180°C, load 5 N, wear radius 6 mm, time 1 h, speed 1130 r / min), the friction coefficient of the coating is 0.43, and the wear rate is 4.63×10 -5 mm 3 / (N•m).

[0059] Example 2

[0060] The cylinder body of the rotary engine is made of aluminum alloy ZAlSi7Mg (brand ZL101).

[0061] In this embodiment, the powder for the high-wear-resistant coating for the inner cavity of the rotary engine cylinder body is prepared using a NiCr alloy powder with a mass percentage of 4:1 (i.e., the NiCr alloy powder has a mass ratio of Ni:Cr=4:1) and a Cr3C2 alloy powder with a mass percentage ratio of 1:3. The particle sizes of the NiCr alloy powder and the Cr3C2 alloy powder with a mass percentage of 4:1 are 10 μm and 2 μm, respectively. The NiCr-CrC powder is used for supersonic flame spraying of the inner cavity of the aluminum alloy cylinder body. The particle size of the NiCr-CrC powder is in the range of 15 μm to 45 μm. The angle of the spray gun relative to the spray surface is 60°, the oxygen flow rate is 800 L / min, and the kerosene flow rate is 26 L / h. The powder feed rate is 30 g / min, the spray gun movement speed is 8 mm / s, and the spray distance is 380 mm. The rotation speed of the rotating shaft is 150 r / min. The spraying process ensures that the surface temperature of the sprayed metal is 50°C to 120°C.

[0062] In this embodiment, the coating thickness is 0.36 mm, and the average hardness of the coating is 1027 HV1. After processing, the coating thickness is 0.15 mm and the roughness is 0.11 μm. Under the conditions of silicon nitride as the grinding material (temperature 180 ° C, load 5 N, wear radius 6 mm, time 1 h, speed 1130 r / min), the friction coefficient of the coating is 0.41, and the wear rate is 4.23×10 -5 mm 3 / (N•m).

[0063] Example 3

[0064] The material of the rotary engine cylinder in the third embodiment is aluminum alloy, the grade of which is ZL107 (GB / T 1173-2013 "Casting Aluminum Alloy" standard).

[0065] In this embodiment, the powder for the high-wear-resistant coating in the inner cavity of the rotary engine cylinder body is prepared using a NiCr alloy powder with a mass percentage of 4:1 (i.e., in the NiCr alloy powder, the mass ratio is Ni:Cr=4:1) and a Cr3C2 alloy powder with a mass percentage ratio of 1:3; the particle sizes of the NiCr alloy powder and the Cr3C2 alloy powder with a mass percentage of 4:1 are 10μm-20μm and 2μm-6μm, respectively; the above-mentioned NiCr-CrC powder is used to perform supersonic flame spraying on the inner cavity of the aluminum alloy cylinder body; the particle size of the NiCr-CrC powder is in the range of 15μm-53μm; the angle of the spray gun relative to the spray surface is 65°, the oxygen flow rate is 830L / min, and the kerosene flow rate is 26L / h; the powder feed rate is 30g / min, the spray gun movement speed is 10mm / s, and the spray distance is 380mm; the rotation speed of the rotating shaft is 150r / min; and the surface temperature of the sprayed metal is ensured to be 50℃-120℃ during the spraying process;

[0066] In this embodiment, the coating thickness is 0.36 mm, and the average hardness of the coating is 1011 HV1. After processing, the coating thickness is 0.15 mm and the roughness is 0.12 μm. Under the conditions of silicon nitride as the grinding material (temperature 180°C, load 5N, wear radius 6 mm, time 1 h, speed 1130 r / min), the friction coefficient of the coating is 0.47, and the wear rate is 4.57×10 -5 mm 3 / (N•m).

[0067] Example 4

[0068] In this embodiment, the rotor engine cylinder body is made of 7075 aluminum alloy.

[0069] In this embodiment, the high-wear-resistant coating for the rotor engine cylinder cavity is made from a 4:1 ratio of NiCr alloy powder and Cr3C2 powder. The average particle sizes of the NiCr alloy and Cr3C2 powders are 20 μm and 6 μm, respectively, and the powders are mixed in a 1:3 ratio. After uniform mixing, the coating powder composition is specifically Ni:20%, C:10%, O:0.02%, and Cr:the remainder. This powder is applied to the 7075 aluminum alloy cylinder cavity via supersonic fuel cell spraying.

[0070] Spraying process parameters are: oxygen flow rate 780L / min, kerosene flow rate 24L / h, powder feed rate 30g / min, spray gun angle relative to the spray surface 60°, spray gun movement speed 6mm / s, spray distance 400mm, and rotary shaft speed 120r / min. During the spraying process, the metal surface temperature is controlled within the range of 50℃ to 120℃.

[0071] In this embodiment, the coating thickness is 0.32 mm and the average hardness of the coating is 935 HV1. After processing, the coating thickness is 0.14 mm and the roughness is 0.12 μm. In tribological tests conducted on silicon nitride grinding materials (temperature 180°C, load 5N, wear radius 6 mm, time 1 hour, speed 1130 r / min), the friction coefficient of the coating is 0.49 and the wear rate is 5.12×10 -5 mm3 / (N•m). Compared with Example 1, the 7075 aluminum alloy coating exhibits a higher friction coefficient and poorer wear resistance.

[0072] Example 5

[0073] In this embodiment, the rotor engine cylinder body is made of aluminum alloy ZL301.

[0074] In this embodiment, the high wear-resistant coating for the inner cavity of the rotary engine cylinder is the same as that in Example 4, and the powder is applied to the inner cavity of the ZL301 cylinder by supersonic flame spraying.

[0075] The spraying process parameters were the same as those in Example 4: oxygen flow rate 780 L / min, kerosene flow rate 24 L / h, powder feed rate 30 g / min, spray gun angle relative to the spray surface 60°, spray gun movement speed 6 mm / s, spray distance 400 mm, and rotary shaft speed 120 rpm. During the spraying process, the metal surface temperature was controlled within the range of 50°C to 120°C.

[0076] In this example, the coating thickness was 0.30 mm, and the average hardness was 920 HV1. After processing, the coating thickness was 0.13 mm, and the roughness was 0.13 μm. The wear test conditions were silicon nitride (temperature 180°C, load 5 N, wear radius 6 mm, time 1 h, rotation speed 1130 rpm). The coating's coefficient of friction was 0.51, and its wear rate was 5.63 × 10⁻⁵ mm³ / (N·m). Compared to Example 4, the ZL301 coating on 7075 aluminum alloy exhibited further increases in friction coefficient and wear rate, indicating poorer wear resistance and friction performance.

[0077] Comparative Example 1

[0078] Other conditions were the same as those in Example 1, except that the high wear-resistant coating powder in the inner cavity of the rotary engine cylinder was prepared using NiCr alloy powder and Cr3C2 alloy powder in a mass ratio of 1:4 in a ratio of 4:1 by mass; the particle sizes of the NiCr alloy powder and Cr3C2 alloy powder in a ratio of 4:1 by mass were 20 μm and 6 μm, respectively; the average hardness of the coating was 1134 HV1; and under the conditions of silicon nitride as the counter-grinding material (temperature 180°C, load 5 N, wear radius 6 mm, time 1 h, and speed 1130 r / min), the friction coefficient of the coating was 0.74, and the wear rate was 10.8×10 -5 mm 3 / (N•m).

[0079] Comparative Example 2

[0080] Other conditions are the same as those in Example 1, except that: the high wear-resistant coating powder for the inner cavity of the rotary engine cylinder body is prepared by using NiCr alloy powder and Cr3C2 alloy powder in a mass percentage ratio of 1:2 in a ratio of 4:1 by mass; the particle sizes of the NiCr alloy powder and Cr3C2 alloy powder in a ratio of 4:1 by mass are 20 μm and 6 μm respectively;

[0081] The average hardness of the coating is 854HV1. Under the conditions of silicon nitride as the counter-grinding material (temperature 180℃, load 5N, wear radius 6mm, time 1h, speed 1130r / min), the friction coefficient of the coating is 0.39 and the wear rate is 6.84×10 -5 mm 3 / (N•m).

[0082] Comparative Example 3

[0083] Other conditions were the same as those in Example 1, except that the angle of the spray gun relative to the spraying surface was 40°.

[0084] The average hardness of the coating is 793HV1. Under the conditions of silicon nitride as the counter-grinding material (temperature 180℃, load 5N, wear radius 6mm, time 1h, speed 1130r / min), the friction coefficient of the coating is 0.84 and the wear rate is 11.3×10 -5 mm 3 / (N•m).

[0085] Comparative Example 4

[0086] Other conditions are consistent with those of Example 1, except that: the high-wear-resistant coating powder for the inner cavity of the rotary engine cylinder body is composed of NiCr alloy powder and Cr3C2 alloy powder in a mass percentage of 4:1 and a configuration of 1:5 by mass; the particle sizes of the NiCr alloy powder and Cr3C2 alloy powder in a mass percentage of 4:1 are 20 μm and 6 μm, respectively; the average hardness of the coating is 1225 HV1; under the condition that the counter-grinding material is silicon nitride (temperature 180°C, load 5 N, wear radius 6 mm, time 1 h, speed 1130 r / min), the friction coefficient of the coating is 0.68, and the wear rate is 9.56×10-5 mm3 / (N•m).

[0087] The present invention relates to a high wear-resistant coating powder and its application, and belongs to the field of high temperature resistant wear-resistant coating technology development. The mass percentages of the components of the high wear-resistant coating powder are: Ni: 19% to 21%, C: 8.5% to 11.3%, O≤0.03%, Cr: balance. The present invention also includes an application of a high wear-resistant coating powder, and the application includes preparing the above-mentioned high wear-resistant coating powder into a wear-resistant coating, especially including using the high wear-resistant coating powder on the inner cavity of the engine cylinder to form a high wear-resistant coating. The high wear-resistant coating powder of the present invention has uniform composition and good sphericity; the preparation process of the high wear-resistant coating is simple and convenient, and it is easy to mass produce; the surface coating thickness uniformity is relatively consistent, the organizational structure is relatively dense and the porosity is low, the interface bite is good, and the crack resistance is good; it can meet the application requirements of long-term operation sealing and wear resistance under high temperature and high speed conditions.

Claims

1. A highly wear-resistant coating powder, characterized in that: The mass percentages of the components of the high wear-resistant coating powder are as follows: Ni: 19% to 21%, C: 8.5% to 11.3%, O≤0.03%, and Cr: the balance.

2. The high wear-resistant coating powder according to claim 1, characterized in that: Prepared by the following steps: S1: NiCr alloy powder and chromium carbide powder are prepared in a mass ratio of 23.5-26.5:73.5-76.5, and mixed evenly. S2 spray-dries, sinters and crushes the mixed powder in a spray granulation tower using alcohol as a solvent; S3 uses an oven to pre-dry the mixed powder to obtain a highly wear-resistant coating powder.

3. The high wear-resistant coating powder according to claim 2, characterized in that: The particle size of the NiCr alloy powder is ≤20 μm, and the mass ratio of Ni to Cr in the NiCr alloy powder is 4:1; the particle size of the chromium carbide powder is in the range of 2 μm to 6 μm.

4. The high wear-resistant coating powder according to claim 2, characterized in that: In step S1, the prepared mixed powder, silicon nitride grinding balls, deionized water, and polyethylene glycol are mixed in a mass ratio of 1:8:3:0.3 for 20 to 36 hours, and the ball mill speed is 300 r / min to 350 r / min.

5. The high wear-resistant coating powder according to claim 2, characterized in that: In S2, the sintering is carried out in an inert protective atmosphere at a sintering temperature of 1150°C to 1250°C.

6. The high wear-resistant coating powder according to claim 2, characterized in that: After step S2, step S21 is further provided: The crushed mixed powder in S21 is screened to obtain a mixed powder with a particle size ranging from 15 μm to 53 μm.

7. The high wear-resistant coating powder according to claim 2, characterized in that: The oven temperature is set at 75-85° C. and the drying time is set at 90-150 min.

8. A use of the high wear-resistant coating powder according to any one of claims 1 to 7, characterized in that: The following steps are involved: A1 installs the engine block to the spraying tooling; A2 engine cylinder inner cavity surface sandblasting treatment; A3 uses supersonic flame spraying to spray high-wear-resistant coating powder onto the inner surface of the rotating cylinder body through a spray gun, obtaining an engine cylinder inner cavity coating that is initially sprayed and qualified.

9. The use of a high wear-resistant coating powder according to claim 8, characterized in that: Also includes step A4: A4 The engine cylinder inner cavity coating that has been preliminarily sprayed and qualified is ground to a coating thickness of 0.15mm±0.01mm by coordinate grinding, with a roughness of ≤0.12um. The thickness of the engine cylinder inner cavity coating that has been preliminarily sprayed and qualified is between 0.3mm and 0.4mm, and the friction coefficient is between 0.35-0.

5.

10. The use of a high wear-resistant coating powder according to claim 8, characterized in that: During spraying, the oxygen flow rate is between 700L / min and 840L / min, the kerosene flow rate is between 20L / h and 26L / h, the powder feeding amount is between 25g / min and 40g / min, and the spray gun moving speed is between 5mm / s and 10mm / s.

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