CN114411147A

CN114411147A - Micro-texture ion-sulfurizing CoCrFeNiMo high-entropy alloy cladding layer and application thereof

Info

Publication number: CN114411147A
Application number: CN202210067588.7A
Authority: CN
Inventors: 韩彬; 孙鑫豪; 胡春阳; 李美艳; 贾晨昕; 王稼林; 李学达; 王勇
Original assignee: China University of Petroleum East China
Current assignee: China University of Petroleum East China
Priority date: 2022-01-20
Filing date: 2022-01-20
Publication date: 2022-04-29

Abstract

The invention discloses a microtextured ion sulfurization CoCrFeNiMo high-entropy alloy cladding layer and application thereof, belonging to the technical field of surface modification and coating. The microtextured ion sulfurization CoCrFeNiMo high-entropy alloy cladding layer is obtained by cladding CoCrFeNiMo high-entropy alloy powder on the surface of a substrate and sequentially carrying out microtexture and sulfurization treatment on the cladding layer. The cladding layer has the advantages of low friction coefficient, long service life and the like, can obviously improve the wear resistance of the matrix, and has wide application prospect.

Description

Micro-texture ion-sulfurizing CoCrFeNiMo high-entropy alloy cladding layer and application thereof

Technical Field

The invention belongs to the technical field of surface modification and coating, and particularly relates to a microtexture ion sulfurization CoCrFeNiMo high-entropy alloy cladding layer and application thereof.

Background

The solid lubrication meets the requirements of harsh working conditions such as vacuum, high temperature, seawater, dry friction and the like on lubrication, and has great development and application prospects. The research on the novel solid self-lubricating film and the preparation technology thereof is a hot point of tribology research. Sulfurization is an economical and effective method for forming a sulfide solid lubricating film on the surface of a friction pair. The ion sulfurizing is a new sulfurizing technology developed independently in China, is an in-situ synthesis process, is known as a 'green' sulfurizing technology due to energy conservation and no pollution, and can realize low-temperature sulfurizing. However, the radius of sulfur atoms is large, and diffusion in metal is difficult, so that the sulfurizing layer is generally thin; in addition, the sulfide solid lubricating film layer is a soft film, is easy to wear in service and is difficult to persist under dry friction and heavy load conditions, so how to improve the service life of the sulfide solid lubricating film layer is an important problem faced by a sulfurizing layer.

Disclosure of Invention

The invention provides a micro-texture ion sulfurization CoCrFeNiMo high-entropy alloy cladding layer, which is obtained by cladding CoCrFeNiMo high-entropy alloy powder on the surface of a substrate and sequentially carrying out micro-texture and sulfurization treatment on the cladding layer. The CoCrFeNiMo high-entropy alloy powder is obtained by uniformly mixing gas atomized powder CoCrFeNi and simple substance powder Mo according to a molar ratio of 1:1 and drying at 100-150 ℃.

In the invention, the microtexture is formed by processing the surface of the cladding layer to form a texture pattern, and the texture pattern is a pit array or a parallel groove. Wherein, the diameter of the pit array is 100-500 μm, and the center distance is 150-1500 μm; the width of the parallel grooves is 50-200 μm, and the center distance is 50-500 μm.

In the present invention, the microtexturing process is performed in a laser marking machine. The pit array is textured by the following parameters: the marking speed is 100-1000 mm/s, the power is 5-20W, the filling radius is 0.001-0.05 mm, the marking frequency is 1-10, the skip speed is 3000mm/s, the Q frequency is 25khz, and the Q release is 1 mu s. The parallel grooves are textured by the following parameters: the marking speed is 100-1000 mm/s, the power is 5-20W, the marking times are 1-10 times, the blank jump speed is 3000mm/s, the Q frequency is 25khz, and the Q release time is 1 mu s.

Before the microtexturing treatment, the surface of the cladding layer can be polished, preferably by sand paper; further preferably, the sandpaper is sequentially sanded with 600#, 1000#, 1500#, and 2000# sandpaper, respectively.

In the invention, the sulfurizing treatment adopts an ion sulfurizing method, and the parameters of the sulfurizing treatment are as follows: the voltage is 520-750V, the heat preservation temperature is 210-290 ℃, and H is₂S, the flow rate of the S is 20-30 sccm, and the heat preservation time is 2-3 h.

In the present invention, cladding is selected from laser cladding. The laser cladding parameters are as follows: the laser power is 1500-5000W, the cladding speed is 200-800 mm/min, and the lap joint rate is 20-50%. Prior to cladding, the substrate surface may preferably be ground to remove scale.

In the cladding process, the thickness of the CoCrFeNiMo high-entropy alloy powder laid on the substrate is preferably 0.8-2 mm. Before the high-entropy alloy powder is laid, the surface of the substrate can be preferably ground to remove the scale.

In the process of marking and constructing the micro texture, oxide and raised burrs are formed on the surface of the woven pattern due to ablation, so that the woven pattern needs to be polished before the sulfurization treatment is carried out to eliminate craters or burrs. The sanding may preferably be with # 2000 sandpaper.

The microtextured ion sulfurization CoCrFeNiMo high-entropy alloy cladding layer has excellent antifriction and wear-resistant performances, so that the antifriction and wear-resistant performances of the matrix can be improved, the use efficiency of the matrix is increased, and the service life of the matrix is prolonged.

In the present invention, the substrate is selected from metallic materials, including but not limited to steel or non-ferrous metals. The steel may be selected from carbon structural and low alloy structural steels (Q195, Q215A, Q215B, Q235A, Q235B, Q235C, etc.), high quality carbon structural and spring steels (08F, 20A, 45E, 65Mn, etc.), structural and spring steels (20CrMnSi, 35CrMo, 60Si2Mn, etc.), tool steels, bearing steels, and stainless steels (2Cr13, 1Cr18Ni9), etc. The non-ferrous metal can be selected from titanium alloy, aluminum alloy, copper alloy, etc.

The invention has the beneficial effects that:

the microtextured ion sulfurization CoCrFeNiMo high-entropy alloy cladding layer has excellent antifriction and wear-resistant performances, and can effectively improve the antifriction and wear-resistant performances of the matrix, thereby increasing the use efficiency and prolonging the service life of the matrix.

Drawings

FIG. 1 is a schematic view of a microtexture ion sulfurizing process;

FIG. 2 is a dye penetrant inspection diagram of a CoCrFeNiMo high-entropy alloy cladding layer on the surface of Q235 steel;

FIG. 3 is a sectional hardness test analysis diagram of a CoCrFeNiMo high-entropy alloy cladding layer;

FIG. 4 is an SEM image before sulfurization of pit texture and groove texture of a CoCrFeNiMo high-entropy alloy cladding layer; wherein, (a) is a low-power SEM image of the pit texture, (b) is a high-power SEM image of the pit texture, (c) is a low-power SEM image of the groove texture, and (d) is a high-power SEM image of the groove texture;

FIG. 5 is a three-dimensional topography before sulfurization of pit texture and groove texture of a CoCrFeNiMo high-entropy alloy cladding layer; wherein (a) is a three-dimensional topographical elevation view of the dimple texture, (b) is a three-dimensional topographical side view of the dimple texture, (c) is a three-dimensional topographical elevation view of the groove texture, and (d) is a three-dimensional topographical side view of the groove texture;

FIG. 6 is a cross-sectional profile data diagram before sulfurization of pit texture and groove texture of a CoCrFeNiMo high-entropy alloy cladding layer; wherein (a) is a cross-sectional profile (depth) map of the pit texture and (b) is a cross-sectional profile (depth) map of the trench texture;

FIG. 7 is a pit weave pattern after sanding;

FIG. 8 is an XPS elemental analysis diagram of internal substances after sulfurization of pit textures and groove textures of a CoCrFeNiMo high-entropy alloy cladding layer;

FIG. 9 is an SEM image of a CoCrFeNiMo high-entropy alloy cladding layer after pit texture and groove texture sulfurization; wherein, (a) is a low-power SEM image of the pit texture, (b) is a high-power SEM image of the pit texture, (c) is a low-power SEM image of the groove texture, and (d) is a high-power SEM image of the groove texture;

FIG. 10 is a graph of the coefficient of friction of different cladding layers as a function of time;

FIG. 11 is SEM images of wear scar profiles of different cladding layers; wherein, (a) is the appearance of a grinding crack of a non-ion sulfurizing cladding layer, (b) is the appearance of a grinding crack of a coating layer of a common ion sulfurizing process, (c) is the appearance of a grinding crack of a cladding layer only textured, and (d) is the appearance of a grinding crack of a micro-texture ion sulfurizing CoCrFeNiMo high-entropy alloy cladding layer; the widths of the grinding traces were 1200 μm, 879 μm, 511 μm and 453 μm in this order.

Detailed Description

Compared with the common ion sulfurizing process, the method also carries out microtexture treatment on the substrate before carrying out the ion sulfurizing process. In order to visually represent the difference between the microtextured ion sulfurization process and the general ion sulfurization process, the present invention provides fig. 1 for a basic illustration and understanding.

The CoCrFeNiMo high-entropy alloy powder adopted by the invention is prepared by the following method: uniformly mixing gas atomized powder CoCrFeNi and simple substance powder Mo according to the molar ratio of 1:1, and drying and dehumidifying at 120 ℃ to obtain CoCrFeNiMo high-entropy alloy powder.

The substrate adopted by the invention is Q235 steel (the size is about 100mm multiplied by 50mm multiplied by 10mm), and the surface of the substrate needs to be polished by a grinding wheel machine before laser cladding to remove oxide skin.

The laser cladding of the invention is carried out in a HWF60 hybrid welding robot workstation under the protection of argon. The laser output by the IPG YLS-6000 fiber laser is transmitted to a rectangular light spot cladding head fixed on a FANUC robot (the model is R-1000iA/100F) through an optical fiber.

The invention adopts a YLP-MP20 laser marking machine to prepare the surface microtexture. The laser mainly comprises an IPG MOPA fiber laser, a master control system, a software operating system and a Germany ScanLab galvanometer system, wherein the laser outputs a laser beam with the wavelength of 1064nm in the running process, the laser beam is expanded by a beam expander and reflected by the galvanometer system, the laser beam moves on a two-dimensional plane under the action of the control system, the laser beam is focused by a focusing lens, and finally a fine high-energy light spot is formed on the surface of a sample, so that the processed surface is instantly vaporized and is irradiated on the surface of the sample point by point according to a preset pattern, and finally a texture shape with a certain depth and width is formed.

The invention adopts the LDMC-15A pulse ion sulfurizing furnace to carry out low-temperature ion sulfurizing.

The method adopts a TIME6610M semi-automatic microhardness tester to measure the microhardness of the section of the cladding layer sample, loads 1.96N, holds the load for 15s, tests once every 0.1mm from the surface of the cladding layer sample to be vertical to a substrate downwards, and averages three rows of tests.

The invention adopts a PHI-Versaprobe 5000III X-ray photoelectron spectrometer to carry out XPS analysis on a sulfurizing sample, wherein an X-ray source is a monochromatized AlKa source, the energy is 1486.6eV, the voltage is 15kV, and the beam current is 4.5 mA.

The invention adopts a Zeta-20 surface profiler to observe the three-dimensional appearance of the texture surface of the cladding layer.

Terms used in the present invention have generally meanings as commonly understood by one of ordinary skill in the art, unless otherwise specified. The present invention will be described in further detail with reference to the following data in conjunction with specific examples. The following examples are intended to illustrate the invention and are not intended to limit the scope of the invention in any way.

Example 1

The preparation method of the microtexture ion sulfurization CoCrFeNiMo high-entropy alloy cladding layer comprises the following steps:

(1) laser cladding

Uniformly paving CoCrFeNiMo high-entropy alloy powder on the surface of Q235 steel by the thickness of 2mm, and carrying out laser cladding under the following laser cladding conditions: laser power is 1800W, cladding speed is 300mm/min, lapping rate is 30%, spot size is 10mm multiplied by 1mm, shielding gas is 4L/min, one cladding pass is performed, a layer of powder is paved on the lapping part, and finally a cladding layer with thickness of about 1mm is formed. After the cladding layer sample is cooled to room temperature in air, impurities such as surface oxidation slag are removed by a grinding wheel machine.

The high-entropy alloy powder is well formed after cladding, and is detected by a flaw detector without red color reaction, which shows that the cladding layer has no crack and flaw detection defects, so that the high-entropy alloy prepared by the method has higher advantages in the aspects of components and preparation. The hardness of the cross section of the cladding layer sample is tested, and the result is shown in fig. 3, and the hardness of the high-entropy alloy layer on the surface of the matrix after cladding is improved by a plurality of times compared with that of the matrix.

(2) Texturing process

And after flaw detection is carried out, cutting the cladding layer sample into samples (15mm multiplied by 10mm) with required sizes by adopting wire electrical discharge machining, then respectively grinding and polishing by using abrasive paper of No. 600, No. 1000, No. 1500 and No. 2000, ultrasonically cleaning in absolute ethyl alcohol for 30min, and then blowing to dry for later use.

And respectively constructing a pit texture and a groove texture on the surfaces of different cladding layer samples. Marking parameters of the pit texture are as follows: the diameter is 200 mu m, the center distance is 600 mu m, the area density is 8.727%, the power is 17W, the marking speed is 200mm/s, the filling radius is 0.005mm, the marking times are 1 time, the skip speed is 3000mm/s, the Q frequency is 25khz, and the Q release is 1 mu s, so that the texture pattern is formed, and the texture pattern is a uniformly distributed pit array. Marking parameters of the groove texture are as follows: the width is 60 μm, the center distance is 400 μm, the area density is 15%, the power is 16W, the marking speed is 400mm/s, the marking times are 5 times, the blank jump speed is 3000mm/s, the Q frequency is 25khz, the Q release is 1 μ s, and the weave pattern is formed and is a parallel groove.

The pit and groove texture is shown in fig. 4, and craters and burrs are formed on the surface of the cladding layer. The three-dimensional topography of the pit and groove texture is shown in fig. 5, and the cross-sectional profile (depth) of the pit and groove texture is shown in fig. 6, as can be seen from fig. 5 and 6, the texture treatment can physically change the surface of the cladding layer, and the formed pits or grooves can not only increase the sulfurization area on the surface of the cladding layer and increase the sulfurization thickness, but also store abrasive dust and lubricating medium, reduce the wear of the abrasive particles on the friction pair, and prevent the loss of the lubricating medium.

And (3) lightly grinding and polishing the texture pattern in one direction by using No. 2000 abrasive paper, removing craters and burrs on the surface of the cladding layer, ultrasonically cleaning the cladding layer in absolute ethyl alcohol for 30 minutes to remove residual polishing paste, oil stains and other stains on the surface, and drying the cladding layer for later use. The polished pit texture pattern is shown in fig. 7, and after the cladding layer is polished, the craters on the surface are polished flat, and the burrs disappear.

(3) Sulfurizing treatment

And carrying out sulfurization treatment on the textured cladding layer sample, wherein the parameters of the sulfurization treatment are as follows: voltage 660V, heat preservation temperature 280 ℃, H₂S gas flow is 24sccm, the heat preservation time is 2h, and the microtextured ion sulfurization CoCrFeNiMo high-entropy alloy cladding layer is obtained after sulfurization treatment.

XPS elemental analysis of material inside the pit and trench texture containing MoS as shown in FIG. 8₂And MoS, which demonstrates the success of the sulfurization treatment. SEM images of the pit and groove textures after sulfurization are shown in fig. 9, and villous substances appear inside both the pit and groove textures, which can be verified with fig. 8, to confirm that the villous substances inside the pit and groove textures are sulfides (main substances of the sulfurization layer), thereby further verifying the combination of the textures and sulfurization, enabling the cladding layer to undergo a great change in physical structure, and facilitating improvement of wear resistance.

Frictional wear test

The microtextured ionically sulfidized CoCrFeNiMo high entropy alloy cladding layer (pit pattern) prepared in example 1 was subjected to a dry friction test. Meanwhile, 3 control groups were set: the control group A is a non-ion-sulfurizing cladding layer, and is a CoCrFeNiMo high-entropy alloy cladding layer formed by performing laser cladding on the surface of Q235 steel; the control group B is a coating of a general ion sulfurization process, and is obtained by sulfurization treatment of a CoCrFeNiMo high-entropy alloy cladding layer; the control group C is a textured cladding layer, and is obtained by texturing a CoCrFeNiMo high-entropy alloy cladding layer.

The tester adopts a WTM-2E type miniature friction and wear tester, and the test parameters are as follows: the rotating speed is 500r/min, the rotating radius is 2.5mm, the load is 1.96N, and the friction time is 1 h. GCr15 material with a diameter of 5mm was used for the grinding balls.

The test results are shown in fig. 10 and 11.

As can be seen from FIG. 10, the friction coefficient of the process of the present invention is lower compared to the general ion sulfurization process, which means that the alloy cladding layer prepared by the present invention is more wear resistant. Meanwhile, the friction coefficient of the cladding layer is higher than that of the cladding layer subjected to combined treatment by simply carrying out ion sulfurization or texturing treatment, which shows that the friction coefficient of the cladding layer can be further effectively reduced by carrying out sulfurization and texturing treatment on the cladding layer simultaneously. There is a synergy between the ionic sulfurization and the texturing treatment.

As can be seen from fig. 11(a), the grinding trace has large abrasive grains, the furrow is deep, and the abrasion loss is large, which pertains to abrasive grain abrasion. As can be seen from fig. 11(b), the wear marks after sulfurization were greatly relieved, the abrasive grains were reduced, the furrows were shallow, and the wear loss was reduced. As can be seen from fig. 11(c), the abrasive grains and furrows disappeared from the wear marks after texturing was added, and they appeared as adhesive wear. As can be seen from fig. 11(d), the texture and the sulphurized wear scar were more slight and smaller in area, with minimal weight loss.

The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.

Claims

1. A micro-texture ion sulfurization CoCrFeNiMo high-entropy alloy cladding layer is characterized in that CoCrFeNiMo high-entropy alloy powder is cladded on the surface of a substrate, and the cladding layer is sequentially subjected to micro-texture and sulfurization treatment to obtain the micro-texture ion sulfurization high-entropy alloy cladding layer.

2. The micro-texture ion-sulfurization CoCrFeNiMo high-entropy alloy cladding layer according to claim 1, wherein the CoCrFeNiMo high-entropy alloy powder is obtained by uniformly mixing gas atomized powder CoCrFeNi and elemental powder Mo according to a molar ratio of 1:1 and then drying at 100-150 ℃.

3. The micro-texture ion-sulfurization CoCrFeNiMo high-entropy alloy cladding layer according to claim 1, wherein the micro-texture is formed by processing the surface of the CoCrFeNiMo high-entropy alloy cladding layer to form a pit array or parallel grooves.

4. The microtextured ion-sulfurization CoCrFeNiMo high-entropy alloy cladding layer according to claim 3, wherein the pit diameter of the pit array is 100-500 μm, and the center distance is 150-1500 μm; the width of the parallel grooves is 50-200 μm, and the center distance is 50-500 μm.

5. The microtextured ionically sulfidized CoCrFeNiMo high entropy alloy cladding layer according to claim 1, wherein the textured pattern in the form of an array of pits is accomplished by a laser marking machine in the following manner: marking speed is 100-1000 mm/s, power is 5-20W, filling radius is 0.001-0.05 mm, marking times are 1-10 times, skip speed is 3000mm/s, Q frequency is 25khz, and Q release is 1 mu s; the parallel groove pattern is formed by a laser marking machine in the following way: the marking speed is 100-1000 mm/s, the power is 5-20W, the marking times are 1-10 times, the blank jump speed is 3000mm/s, the Q frequency is 25khz, and the Q release time is 1 mu s.

6. The micro-texture ion-sulfurization CoCrFeNiMo high-entropy alloy cladding layer according to claim 1, wherein the sulfurization treatment is an ion sulfurization treatment on the surface of the micro-texture CoCrFeNiMo high-entropy alloy cladding layer; the sulfurizing treatment parameters are as follows: the voltage is 520-750V, the heat preservation temperature is 210-290 ℃, and H is₂S, the flow rate of the S is 20-30 sccm, and the heat preservation time is 2-3 h.

7. The microtextured ionically sulfidized CoCrFeNiMo high entropy alloy cladding layer according to claim 1, wherein cladding is selected from laser cladding; the laser cladding parameters are as follows: the laser power is 1500-5000W, the cladding speed is 200-800 mm/min, and the lap joint rate is 20-50%.

8. The application of the microtextured ion-sulfurizing CoCrFeNiMo high-entropy alloy cladding layer of any one of claims 1 to 7 in improving the wear-reducing and wear-resisting properties of a matrix.

9. The use according to claim 8, wherein the substrate is a metallic material.

10. Use according to claim 9, the metallic material being selected from steel or non-ferrous metals; preferably, the steel is selected from the group consisting of carbon structural steel, low alloy structural steel, high quality carbon spring steel, alloy structural steel, alloy spring steel, tool steel, bearing steel, and stainless steel; the non-ferrous metal is selected from titanium alloy, aluminum alloy and copper alloy.