阅读说明：本技术 一种盾构机刀具表面自润滑硬质复合涂层的制备方法 (Preparation method of self-lubricating hard composite coating on surface of shield machine cutter ) 是由 周嘉利 程延海 韩正铜 杨金勇 王情情 陈浩 韩忠臣 于 2021-08-03 设计创作，主要内容包括：一种盾构机刀具表面自润滑硬质复合涂层的制备方法,刀具基体材料为高速钢,采用激光熔覆在刀具基体表面依次制备NiCoCrAlY粘黏层和WC-TiC-NbC-Co-Ti-(3)AlC-(2)涂层。本发明所制备的WC-TiC-NbC-Co-Ti-(3)AlC-(2)涂层无裂纹并且和基体形成良好的冶金结合,NiCoCrAlY粘黏层具有良好的粘黏效果。WC-TiC-NbC-Co-Ti-(3)AlC-(2)体系中,WC、TiC和NbC均为硬质相使涂层具有高硬度,Co起到连接硬质相的作用,Ti-(3)AlC-(2)具有良好的自润滑性能,极大的降低了涂层的摩擦因数。该涂层具有高硬度和良好的耐磨损能力,极大地提高了盾构机刀具的切削能力,延长了刀具的使用寿命。(A method for preparing self-lubricating hard composite coating on the surface of shield machine tool includes using high-speed steel as base material of tool, preparing NiCoCrAlY adhesive layer and WC-TiC-NbC-Co-Ti in sequence on the surface of tool base by laser cladding 3 AlC 2 And (4) coating. The WC-TiC-NbC-Co-Ti prepared by the invention 3 AlC 2 The coating has no cracksAnd the NiCoCrAlY adhesive layer has good adhesion effect. WC-TiC-NbC-Co-Ti 3 AlC 2 In the system, WC, TiC and NbC are hard phases so that the coating has high hardness, Co plays a role in connecting the hard phases, and Ti 3 AlC 2 Has good self-lubricating performance, and greatly reduces the friction factor of the coating. The coating has high hardness and good wear resistance, greatly improves the cutting capability of the shield machine cutter, and prolongs the service life of the cutter.)

1. A method for preparing self-lubricating hard composite coating on the surface of shield machine cutter, the base material of the cutter is high-speed steel, characterized in that NiCoCrAlY alloy powder and WC-TiC-NbC-Co-Ti are used₃AlC₂The alloy powder is used as a coating material, and a NiCoCrAlY adhesive layer and WC-TiC-NbC-Co-Ti are sequentially prepared on the surface of a cutter substrate by laser cladding₃AlC₂And (4) coating.

2. The method for preparing the self-lubricating hard composite coating on the surface of the shield tunneling machine cutter according to claim 1, wherein the self-lubricating hard composite coating is WC-TiC-NbC-Co-Ti₃AlC₂The alloy powder is prepared by mixing, ball-milling and drying the following raw materials in percentage by mass: 78-79% of WC powder, 5.1-5.6% of TiC powder, 3.5-3.7% of NbC powder, and Ti₃AlC₂6.2-6.5% of powder and the balance of Co powder; WC-TiC-NbC-Co-Ti₃AlC₂The particle size of the alloy powder is 50-100 μm.

3. The method for preparing the self-lubricating hard composite coating on the surface of the shield tunneling machine cutter according to the claim 1 or 2, characterized in that WC-TiC-NbC-Co-Ti₃AlC₂The alloy powder is paved on the surface of the NiCoCrAlY sticky layer in a synchronous powder feeding mode, the powder feeding speed is 10-14 mL/min, the gas feeding speed is 8-12L/min, and argon is used for the powder feeding gas and the shielding gas; using a laser with a power of 1200-1600W, a spot diameter of 3-5 mm and a laser scanning speed of 3-longFor WC-TiC-NbC-Co-Ti under the condition of 5mm/s laser cladding process₃AlC₂The alloy powder was laser scanned.

4. The method for preparing the self-lubricating hard composite coating on the surface of the shield tunneling machine cutter according to the claim 1 or 2, characterized in that NiCoCrAlY alloy powder is spread on the surface of the cutter substrate in a synchronous powder feeding mode, the powder feeding speed is 9-11 mL/min, the gas feeding speed is 8-12L/min, and argon is used for both the powder feeding gas and the protective gas; and (3) carrying out laser scanning on NiCoCrAlY alloy powder by using laser with the power of 900-1200W under the laser cladding process condition that the spot diameter is 3-5 mm and the laser scanning speed is 4-6 mm/s.

5. The preparation method of the self-lubricating hard composite coating on the surface of the shield tunneling machine cutter according to the claim 1 or 2, characterized in that NiCoCrAlY alloy powder is obtained by mixing, ball-milling and drying the following raw materials in percentage by mass: 22-24% of Co powder, 16-18% of Cr powder, 11.5-12.5% of Al powder, 0.4-0.6% of Y powder and the balance of Ni powder; the particle size of the NiCoCrAlY alloy powder is 50-100 mu m.

6. The method for preparing the self-lubricating hard composite coating on the surface of the shield tunneling machine cutter according to claim 1 or 2, wherein the thickness of the NiCoCrAlY sticky layer is 0.25-0.4 mm; WC-TiC-NbC-Co-Ti₃AlC₂The thickness of the coating is 1.2-1.5 mm.

7. The method for preparing the self-lubricating hard composite coating on the surface of the shield tunneling machine cutter according to the claim 1 or 2, characterized in that after the NiCoCrAlY sticky layer is prepared by laser cladding, the surface of the sticky layer is mechanically ground.

8. The method for preparing the self-lubricating hard composite coating on the surface of the shield tunneling machine cutter according to the claim 1 or 2, characterized in that before laser scanning cladding, the surface of the cutter substrate is ground by sand paper, washed by solvent, and then quenched and tempered.

9. The preparation method of the self-lubricating hard composite coating on the surface of the shield tunneling machine cutter according to the claim 1 or 2, characterized in that the model of the high-speed steel is T-4241, and the high-speed steel comprises the following components in percentage by mass: 0.9 to 1% of C, 1.5 to 2.5% of W, 3.8 to 4.4% of Cr, 0.5 to 1.2% of Mo, 0.2 to 0.4% of Mn, 0.5 to 1% of Si, and the balance Fe.

Technical Field

The invention belongs to the technical field of coatings, and particularly relates to a preparation method of a self-lubricating hard composite coating on the surface of a shield machine cutter.

Background

In recent years, shield machines are widely used in urban tunnel excavation, and cutters of the shield machines are seriously worn when the shield machines work in a sandy gravel stratum. The shield machine has to be opened frequently for tool changing during construction, which increases the construction cost and reduces the working efficiency of the shield machine, therefore, the improvement of the wear resistance of the shield machine tool has important significance.

The hard cutter coating is prepared on the surface of the high-speed steel by laser cladding, so that the cutter can achieve the effects of hardness outside and toughness inside, the hardness and wear resistance of the cutter can be improved, and the cutter has high impact toughness and bending strength. However, since the hard coating is brittle and the cooling rate of laser cladding is very high, it is easy to generate large residual stress in the coating, which leads to problems of cracking of the coating, low bonding strength of the substrate and the coating, and the like. In addition, the cemented carbide coating has good cutting ability, but the peeling of hard phase in the coating increases the friction factor and causes severe abrasive wear to make the coating wear more severe, so that the coating needs to have both high hardness and low friction factor. Therefore, the shield machine cutter coating with high hardness and low friction factor is developed, so that the service life and the working efficiency of the shield machine cutter can be greatly improved, and the shield machine cutter coating has important engineering application value.

The patent with publication number CN110205624A discloses a laminated hard coating self-lubricating cutter and a preparation method thereof, wherein a hard alloy layer, an alumina ceramic layer and a cubic boron nitride layer are sequentially prepared on the surface of high-speed steel by laser cladding, but the method has the defect of untight combination of a coating and a matrix, and does not disclose performance parameters such as hardness, friction factor and the like of the self-lubricating cutter; the patent with the publication number of CN103522652A discloses a preparation method of a laser cladding soft-hard composite coating self-lubricating cutter, which adopts laser cladding to clad MoS on the front cutter surface of the cutter₂Or WS₂Self-lubricating soft coating and nano-A₂O₃Composite coatings of hard coatings of ceramics or ultra-fine cemented carbide, but MoS₂And WS₂The cutter is easy to decompose at high temperature, and is not suitable for high-temperature environment; patent publication No. CN105925941A discloses TiAlCrN + MoS₂In the method, TiAlCrN + MoS is compositely deposited on high-speed steel by arc ion plating and unbalanced magnetron sputtering₂The method has the advantages of high cost, complex process, reduction of 20-25% of tool abrasion loss and poor antifriction effect. The above techniques have problems of non-tight coating-substrate combination, poor high temperature resistance, complex process and the like.

Disclosure of Invention

The invention aims to provide a preparation method of a self-lubricating hard composite coating on the surface of a shield machine cutter, which has simple process, can improve the bonding tightness of the coating and a substrate, improve the hardness of the surface of the cutter and reduce the friction factor of the surface of the cutter, thereby enhancing the wear resistance of the cutter, improving the cutting capability of the cutter and prolonging the service life of the cutter.

In order to achieve the aim, the invention provides a preparation method of a self-lubricating hard composite coating on the surface of a shield machine cutter, and a cutter base materialThe high-speed steel is made of NiCoCrAlY alloy powder and WC-TiC-NbC-Co-Ti₃AlC₂The alloy powder is used as a coating material, and a NiCoCrAlY adhesive layer and WC-TiC-NbC-Co-Ti are sequentially prepared on the surface of a cutter substrate by laser cladding₃AlC₂And (4) coating.

Preferably, WC-TiC-NbC-Co-Ti₃AlC₂The alloy powder is prepared by mixing, ball-milling and drying the following raw materials in percentage by mass: 78-79% of WC powder, 5.1-5.6% of TiC powder, 3.5-3.7% of NbC powder, and Ti₃AlC₂6.2-6.5% of powder and the balance of Co powder; WC-TiC-NbC-Co-Ti₃AlC₂The particle size of the alloy powder is 50-100 μm.

Further, mixing WC-TiC-NbC-Co-Ti₃AlC₂The alloy powder is paved on the surface of the NiCoCrAlY sticky layer in a synchronous powder feeding mode, the powder feeding speed is 10-14 mL/min, the gas feeding speed is 8-12L/min, and argon is used for the powder feeding gas and the shielding gas; carrying out laser cladding on WC-TiC-NbC-Co-Ti by using a laser with the power of 1200-1600W under the laser cladding process conditions that the spot diameter is 3-5 mm and the laser scanning speed is 3-5 mm/s₃AlC₂The alloy powder was laser scanned.

Further, NiCoCrAlY alloy powder is laid on the surface of the cutter substrate in a synchronous powder feeding mode, the powder feeding speed is 9-11 mL/min, the gas feeding speed is 8-12L/min, and argon is used for both powder feeding gas and protective gas; and (3) carrying out laser scanning on NiCoCrAlY alloy powder by using laser with the power of 900-1200W under the laser cladding process condition that the spot diameter is 3-5 mm and the laser scanning speed is 4-6 mm/s.

Preferably, the NiCoCrAlY alloy powder is obtained by mixing, ball-milling and drying the following raw materials in percentage by mass: 22-24% of Co powder, 16-18% of Cr powder, 11.5-12.5% of Al powder, 0.4-0.6% of Y powder and the balance of Ni powder; the particle size of the NiCoCrAlY alloy powder is 50-100 mu m.

Preferably, the thickness of the NiCoCrAlY sticky layer is 0.25-0.4 mm; WC-TiC-NbC-Co-Ti₃AlC₂The thickness of the coating is 1.2-1.5 mm.

Further, after the NiCoCrAlY sticky layer is prepared by laser cladding, the surface of the sticky layer is mechanically ground.

Further, before laser scanning cladding, the surface of the tool base body is polished by sand paper, washed by solvent, and then quenched and tempered.

Preferably, the high-speed steel is T-4241, and the high-speed steel comprises the following components in percentage by mass: 0.9 to 1% of C, 1.5 to 2.5% of W, 3.8 to 4.4% of Cr, 0.5 to 1.2% of Mo, 0.2 to 0.4% of Mn, 0.5 to 1% of Si, and the balance Fe.

The NiCoCrAlY coating is compact, high in bonding strength, corrosion resistant, cavitation resistant, capable of resisting high temperature of 982 ℃, excellent in oxidation resistance and commonly used as a bonding transition layer of a high-temperature heat-resistant coating; the WC-TiC-NbC-Co quaternary alloy has high hardness, can resist the high temperature of 850-1000 ℃, and has the cutting speed 4-10 times higher than that of high-speed steel; ti₃AlC₂Is MAX self-lubricating phase, in the crystal cell structure of the MAX self-lubricating phase, Ti and C are strong covalent bonds, Al only has weak bonding force in the MAX self-lubricating phase, and an Al plane is easy to slip, so that Ti and C have strong bonding force, and the like₃AlC₂Has self-lubricating property.

The WC-TiC-NbC-Co-Ti prepared by the invention₃AlC₂The coating has no crack and forms good metallurgical bonding with the matrix, and the NiCoCrAlY sticky layer has good sticky effect. Performing performance test on the obtained coating, wherein the hardness of the obtained coating is 1030-1070 HV₁The friction factor is 0.33-0.35, and the wear rate is 5.8-6.1 μm³·N^-1·mm^-1。WC-TiC-NbC-Co-Ti₃AlC₂In the system, WC, TiC and NbC are hard phases so that the coating has high hardness, Co plays a role in connecting the hard phases, and Ti₃AlC₂Has good self-lubricating performance, and greatly reduces the friction factor of the coating. The invention has simple process, the prepared coating has high bonding tightness with the cutter substrate, the hardness of the cutter surface is improved by the coating, and the friction factor of the cutter surface is reduced, thereby enhancing the wear resistance of the cutter, greatly improving the cutting capability of the cutter and prolonging the service life of the cutter.

Drawings

FIG. 1 is a schematic structural view of a cross section of a coating prepared by an example;

FIG. 2 is an SEM image of the coating profile obtained by the first preparation of example;

FIG. 3 is a graph of hardness profile of the coating prepared in the first example;

FIG. 4 is a plot of friction factor versus time for the coating prepared in example one;

FIG. 5 is a graph of the wear scar profile of the coating prepared in the first example.

Detailed Description

The invention is further described with reference to the following figures and specific examples.

Example one

A method for preparing a self-lubricating hard composite coating on the surface of a shield machine cutter is characterized in that a cutter base material is T-4241 high-speed steel and comprises the following components in percentage by mass: 0.9-1% of C, 1.5-2.5% of W, 3.8-4.4% of Cr, 0.5-1.2% of Mo, 0.2-0.4% of Mn, 0.5-1% of Si, and the balance of Fe; the method specifically comprises the following steps:

(1) 80 to 1200 parts by weight^#Sanding the surface of the tool base body by using abrasive paper, cleaning by using alcohol, and then quenching and tempering;

(2) preparing NiCoCrAlY alloy powder: the alloy powder is prepared by mixing, ball-milling and drying the following raw materials in percentage by mass: 23% of Co powder, 17% of Cr powder, 12% of Al powder, 0.5% of Y powder and the balance of Ni powder; preparation of WC-TiC-NbC-Co-Ti₃AlC₂The alloy powder is prepared by mixing, ball-milling and drying the following raw materials in percentage by mass: 78.5% of WC powder, 5.6% of TiC powder, 3.7% of NbC powder and Ti₃AlC₂6.5% of powder and the balance of Co powder; the granularity of the two alloy powders is 50-100 mu m; uniformly mixing the two alloy powders by adopting a QM-3 SP04L type planetary ball mill, wherein the ball milling parameters are as follows: the rotating speed is 600r/min, the time is 2.5h, and the temperature is room temperature; the two alloy powders are respectively put into a 101-00B type electric heating air blast constant temperature drying oven to be dried for 1h at the temperature of 120 ℃ so as to ensure that the powders are not affected with damp and have good fluidity;

(3) laser cladding is carried out on a ZKSX-2000W type optical fiber coupling laser spraying system, NiCoCrAlY alloy powder is laid on the surface of a cutter matrix in a synchronous powder feeding mode, the powder feeding speed is 10mL/min, the gas feeding speed is 10L/min, the overlapping rate is 50%, and argon is adopted for powder feeding gas and protective gas; carrying out laser scanning on NiCoCrAlY alloy powder by using a laser with the power of 1000W under the laser cladding process conditions that the spot diameter is 4mm and the laser scanning speed is 5 mm/s; after preparing a NiCoCrAlY sticky layer by laser cladding, mechanically grinding the surface of the sticky layer to remove impurities and oxide skin of unfused powder; the thickness of the NiCoCrAlY sticky layer is 0.3 mm;

(4) mixing WC-TiC-NbC-Co-Ti₃AlC₂The alloy powder is paved on the surface of the NiCoCrAlY sticky layer in a synchronous powder feeding mode, the powder feeding speed is 12mL/min, the gas feeding speed is 10L/min, the overlapping rate is 50%, and the powder feeding gas and the shielding gas both adopt argon gas; using laser with power of 1400W to perform laser cladding on WC-TiC-NbC-Co-Ti under the laser cladding process conditions that the spot diameter is 4mm and the laser scanning speed is 4mm/s₃AlC₂Carrying out laser scanning on the alloy powder; WC-TiC-NbC-Co-Ti₃AlC₂The coating thickness was 1.3 mm.

As shown in fig. 1, the composite coating prepared in this embodiment is subjected to SEM, hardness, friction factor, friction profile, and other detection, and the detection method includes the following steps and results:

cutting the obtained sample into samples with the size of 15 multiplied by 5mm, and adopting 80-2000^#The surface and the cross section of the coating are mechanically ground by sand paper, and are polished by flocking polishing cloth and a diamond polishing agent, and the grain diameter of the diamond is 0.5 mu m. And removing impurities and grease on the surface of the sample by using an ultrasonic cleaning machine, wherein the cleaning agent is absolute alcohol and the time is 5 min.

Corroding the section of the coating for 2s by using a copper sulfate-hydrochloric acid solution, and observing the layering condition of the section of the coating by using a scanning electron microscope, wherein the corrosion solution is prepared from the following components in percentage by weight: 100ml of hydrochloric acid, 5ml of sulfuric acid and 5g of copper sulfate. As can be seen from fig. 2: the section of the coating is divided into WC-TiC-NbC-Co-Ti₃AlC₂The coating, NiCoCrAlY sticky layer, heat affected zone and base body, the coating section does not have crackle, and coating-sticky layer interface and sticky layer-base body interface all combine closely, and NiCoCrAlY sticky layer has good sticky effect.

Coating hardness is measured by adopting HVS-1000M type Vickers hardness testerAnd experimental parameters are as follows: load 10N, dwell time 10 s. And (5) punching points at intervals of 100 mu m in the depth direction of the surface of the coating to obtain the hardness distribution of the section of the coating. As can be seen in fig. 3: WC-TiC-NbC-Co-Ti₃AlC₂The coating hardness is 1042 +/-36 HV₁The hardness of the NiCoCrAlY sticky layer is 322 +/-20 HV₁The hardness of the heat-affected zone and that of the base body are 524 + -29 HV₁And 629. + -. 30HV₁。

The wear resistance of the coating is measured by adopting an HT-1000 type high-temperature wear experiment machine, and the experiment parameters are as follows: 15N load, 650 ℃, 30min test time, 500rpm frequency, 2.5mm rotation radius and Si as the material of the opposite grinding pair₃N₄A ball. As can be seen from fig. 4 and 5: WC-TiC-NbC-Co-Ti₃AlC₂The friction factor of the coating is 0.332, and the wear rate is 5.81 mu m³·N^-1·mm^-1。

Example two

A method for preparing a self-lubricating hard composite coating on the surface of a shield machine cutter is characterized in that a cutter base material is T-4241 high-speed steel and comprises the following components in percentage by mass: 0.9-1% of C, 1.5-2.5% of W, 3.8-4.4% of Cr, 0.5-1.2% of Mo, 0.2-0.4% of Mn, 0.5-1% of Si, and the balance of Fe; the method specifically comprises the following steps:

(1) preparing NiCoCrAlY alloy powder: the alloy powder is prepared by mixing, ball-milling and drying the following raw materials in percentage by mass: 22% of Co powder, 18% of Cr powder, 11.5% of Al powder, 0.6% of Y powder and the balance of Ni powder; preparation of WC-TiC-NbC-Co-Ti₃AlC₂The alloy powder is prepared by mixing, ball-milling and drying the following raw materials in percentage by mass: 78% of WC powder, 5.1% of TiC powder, 3.6% of NbC powder and Ti₃AlC₂6.2% of powder and the balance of Co powder; the granularity of the two alloy powders is 50-100 mu m; uniformly mixing the two alloy powders by adopting a QM-3 SP04L type planetary ball mill, wherein the ball milling parameters are as follows: the rotating speed is 600r/min, the time is 2.5h, and the temperature is room temperature; the two alloy powders are respectively put into a 101-00B type electric heating air blast constant temperature drying oven to be dried for 1h at the temperature of 120 ℃ so as to ensure that the powders are not affected with damp and have good fluidity;

(2) the NiCoCrAlY alloy powder is laid on the surface of the cutter matrix in a synchronous powder feeding mode, the powder feeding speed is 9mL/min, the gas feeding speed is 8L/min, the overlapping rate is 50%, and argon is used for the powder feeding gas and the shielding gas; carrying out laser scanning on NiCoCrAlY alloy powder by using a laser with the power of 900W under the laser cladding process conditions that the spot diameter is 3mm and the laser scanning speed is 4 mm/s; the thickness of the NiCoCrAlY sticky layer is 0.25 mm;

(3) mixing WC-TiC-NbC-Co-Ti₃AlC₂The alloy powder is paved on the surface of the NiCoCrAlY sticky layer in a synchronous powder feeding mode, the powder feeding speed is 10mL/min, the gas feeding speed is 8L/min, the overlapping rate is 50%, and the powder feeding gas and the shielding gas both adopt argon gas; using a laser with the power of 1200W to carry out laser cladding on WC-TiC-NbC-Co-Ti under the laser cladding process conditions that the spot diameter is 5mm and the laser scanning speed is 5mm/s₃AlC₂Carrying out laser scanning on the alloy powder; WC-TiC-NbC-Co-Ti₃AlC₂The coating thickness was 1.2 mm.

Fig. 1 shows the composite coating prepared in this example, and SEM, hardness, friction factor, friction profile and other tests are performed on the composite coating, the test method is the same as in the first example, and the results are as follows:

observing the layering condition of the coating section by a scanning electron microscope, wherein the coating section is divided into WC-TiC-NbC-Co-Ti₃AlC₂The coating, NiCoCrAlY sticky layer, heat affected zone and base body, the coating section does not have crackle, and coating-sticky layer interface and sticky layer-base body interface all combine closely, and NiCoCrAlY sticky layer has good sticky effect.

The hardness test results are as follows: WC-TiC-NbC-Co-Ti₃AlC₂The coating hardness is 1035 +/-27 HV₁The hardness of the NiCoCrAlY sticky layer is 313 +/-16 HV₁The hardness of the heat-affected zone and that of the base body are 536. + -. 33HV₁And 619 +/-22 HV₁。

The wear resistance test result of the coating is as follows: WC-TiC-NbC-Co-Ti₃AlC₂The friction factor of the coating is 0.345, and the wear rate is 6.02 mu m³·N^-1·mm^-1。

EXAMPLE III

A method for preparing a self-lubricating hard composite coating on the surface of a shield machine cutter, wherein the cutter base material is high-speed steel, comprises the following steps:

(1) 80 to 1200 parts by weight^#Sanding the surface of the tool base body by using abrasive paper, cleaning by using alcohol, and then quenching and tempering;

(2) preparing NiCoCrAlY alloy powder: the alloy powder is prepared by mixing, ball-milling and drying the following raw materials in percentage by mass: 24% of Co powder, 16% of Cr powder, 12.5% of Al powder, 0.4% of Y powder and the balance of Ni powder; preparation of WC-TiC-NbC-Co-Ti₃AlC₂The alloy powder is prepared by mixing, ball-milling and drying the following raw materials in percentage by mass: 79% of WC powder, 5.3% of TiC powder, 3.5% of NbC powder and Ti₃AlC₂6.3% of powder and the balance of Co powder; the granularity of the two alloy powders is 50-100 mu m;

(3) laser cladding is carried out on a ZKSX-2000W type optical fiber coupling laser spraying system, NiCoCrAlY alloy powder is laid on the surface of a cutter matrix in a synchronous powder feeding mode, the powder feeding speed is 11mL/min, the gas feeding speed is 12L/min, the overlapping rate is 50%, and argon is used for both the powder feeding gas and the protective gas; carrying out laser scanning on NiCoCrAlY alloy powder by using a laser with the power of 1200W under the laser cladding process conditions that the spot diameter is 5mm and the laser scanning speed is 6 mm/s; after preparing a NiCoCrAlY sticky layer by laser cladding, mechanically grinding the surface of the sticky layer to remove impurities and oxide skin of unfused powder; the thickness of the NiCoCrAlY sticky layer is 0.40 mm;

(4) mixing WC-TiC-NbC-Co-Ti₃AlC₂The alloy powder is paved on the surface of the NiCoCrAlY sticky layer in a synchronous powder feeding mode, the powder feeding speed is 14mL/min, the gas feeding speed is 12L/min, the overlapping rate is 50%, and the powder feeding gas and the shielding gas both adopt argon gas; using laser with power of 1600W to carry out laser cladding on WC-TiC-NbC-Co-Ti under the laser cladding process conditions that the spot diameter is 3mm and the laser scanning speed is 3mm/s₃AlC₂Carrying out laser scanning on the alloy powder; WC-TiC-NbC-Co-Ti₃AlC₂The coating thickness was 1.5 mm.

Fig. 1 shows the composite coating prepared in this example, and SEM, hardness, friction factor, friction profile and other tests are performed on the composite coating, the test method is the same as in the first example, and the results are as follows:

observing the layering condition of the coating section by a scanning electron microscope, wherein the coating section is divided into WC-TiC-NbC-Co-Ti₃AlC₂The coating, NiCoCrAlY sticky layer, heat affected zone and base body, the coating section does not have crackle, and coating-sticky layer interface and sticky layer-base body interface all combine closely, and NiCoCrAlY sticky layer has good sticky effect.

The hardness test results are as follows: WC-TiC-NbC-Co-Ti₃AlC₂The coating hardness is 1066 +/-31 HV₁The hardness of the NiCoCrAlY sticky layer is 321 +/-17 HV₁The hardness of the heat-affected zone and that of the base body are 533 + -24 HV₁And 637. + -. 25HV₁。

The wear resistance test result of the coating is as follows: WC-TiC-NbC-Co-Ti₃AlC₂The coating had a friction factor of 0.339 and a wear rate of 5.97 μm³·N^-1·mm^-1。

Comparative example

The laser cladding parameter and performance test method of the embodiment I is adopted, and WC-TiC-NbC-Co alloy powder is used for preparing the WC-TiC-NbC-Co hard alloy coating without self-lubricating performance. The cutter base material is T-4241 high-speed steel and comprises the following components in percentage by mass: 0.9-1% of C, 1.5-2.5% of W, 3.8-4.4% of Cr, 0.5-1.2% of Mo, 0.2-0.4% of Mn, 0.5-1% of Si, and the balance of Fe; the method specifically comprises the following steps:

(1) 80 to 1200 parts by weight^#Sanding the surface of the tool base body by using abrasive paper, cleaning by using alcohol, and then quenching and tempering;

(2) preparing NiCoCrAlY alloy powder: the alloy powder is prepared by mixing, ball-milling and drying the following raw materials in percentage by mass: 23% of Co powder, 17% of Cr powder, 12% of Al powder, 0.5% of Y powder and the balance of Ni powder; preparing WC-TiC-NbC-Co alloy powder, wherein the powder is prepared by mixing, ball-milling and drying the following raw materials in percentage by mass: 78.5% of WC powder, 5.6% of TiC powder, 3.7% of NbC powder and the balance of Co powder; the granularity of the two alloy powders is 50-100 mu m; uniformly mixing the two alloy powders by adopting a QM-3 SP04L type planetary ball mill, wherein the ball milling parameters are as follows: the rotating speed is 600r/min, the time is 2.5h, and the temperature is room temperature; the two alloy powders are respectively put into a 101-00B type electric heating air blast constant temperature drying oven to be dried for 1h at the temperature of 120 ℃ so as to ensure that the powders are not affected with damp and have good fluidity;

(3) laser cladding is carried out on a ZKSX-2000W type optical fiber coupling laser spraying system, NiCoCrAlY alloy powder is laid on the surface of a cutter matrix in a synchronous powder feeding mode, the powder feeding speed is 10mL/min, the gas feeding speed is 10L/min, the overlapping rate is 50%, and argon is adopted for powder feeding gas and protective gas; carrying out laser scanning on NiCoCrAlY alloy powder by using a laser with the power of 1000W under the laser cladding process conditions that the spot diameter is 4mm and the laser scanning speed is 5 mm/s; after preparing a NiCoCrAlY sticky layer by laser cladding, mechanically grinding the surface of the sticky layer to remove impurities and oxide skin of unfused powder; the thickness of the NiCoCrAlY sticky layer is 0.3 mm;

(4) the method comprises the following steps of (1) paving WC-TiC-NbC-Co alloy powder on the surface of a NiCoCrAlY sticky layer in a synchronous powder feeding mode, wherein the powder feeding speed is 12mL/min, the gas feeding speed is 10L/min, the overlapping rate is 50%, and argon is used for both powder feeding gas and shielding gas; carrying out laser scanning on WC-TiC-NbC-Co alloy powder by using laser with the power of 1400W under the laser cladding process condition that the spot diameter is 4mm and the laser scanning speed is 4 mm/s; the thickness of the WC-TiC-NbC-Co coating is 1.4 mm.

The composite coating is detected by SEM, hardness, friction factors, friction profile and the like, the detection method and the process are the same as those of the first embodiment, and the result is as follows:

the layering condition of the coating section is observed by a scanning electron microscope, the coating section is divided into a WC-TiC-NbC-Co coating, a NiCoCrAlY adhesive layer, a heat affected zone and a matrix, the coating section has no cracks, the coating-adhesive layer interface and the adhesive layer-matrix interface are tightly combined, and the NiCoCrAlY adhesive layer has a good adhesive effect.

The hardness test results are as follows: the hardness of the WC-TiC-NbC-Co coating is 1152 +/-41 HV₁The hardness of the NiCoCrAlY sticky layer is 314 +/-18 HV₁The hardness of the heat-affected zone and that of the base body are 531. + -. 23HV₁And 603 + -36 HV₁。

The wear resistance test result of the coating is as follows: the friction factor of the WC-TiC-NbC-Co coating is 0.545, and the wear rate is 16.77 mu m³·N^-1·mm^-1。

The results of the first embodiment, the second embodiment and the third embodiment show that the proportion of the alloy powder and the laser cladding parameters can influence the thickness of the coating and the self-lubricating antifriction effect, and the coatings prepared in the first embodiment to the third embodiment all show good combination effect and self-lubricating antifriction performance. As shown by the results of example one and comparative example, WC-TiC-NbC-Co-Ti₃AlC₂Ti in the coating₃AlC₂The self-lubricating phase has good friction reducing and wear reducing effects, and the friction factor and the wear rate of the coating are respectively reduced by 39.1 percent and 65.4 percent.