Iron-based amorphous powder suitable for synchronous powder feeding laser cladding coating, its preparation method and application

Abstract

This invention discloses an iron-based amorphous powder suitable for simultaneous powder feeding laser cladding coatings, its preparation method, and its application, belonging to the field of surface engineering technology. The elements and their atomic percentages in the iron-based amorphous powder are: Co: 10-15%, Cr: 5-10%, Mo: 35-40%, C: 0.2-0.4%, B: 0.2-0.5%, Y: 0.2-0.5%, Al: 0.2-0.6%, and the balance being Fe. The iron-based amorphous powder provided by this invention has excellent flowability and filling properties, an amorphous content greater than 90%, and uniform particle size distribution with high sphericity. The coating prepared using the iron-based amorphous powder of this invention as the initial powder for simultaneous powder feeding laser cladding has the characteristics of dense and uniform structure, few pores, few unmelted particles, an amorphous content of over 90%, good adhesion to the substrate, and high hardness.

Description

Technical Field

[0001] This invention relates to the field of surface engineering technology, specifically to an iron-based amorphous powder suitable for synchronous powder feeding laser cladding coating, its preparation method, and its application. Background Technology

[0002] Amorphous alloys are special materials characterized by a disordered atomic structure, which can be prepared by rapid solidification of liquid metal. Due to their disordered structure, amorphous alloys lack the structural and defect features found in crystalline alloys, such as vacancies, dislocations, and slip. This endows amorphous alloys with unique physical and chemical properties, including mechanical, magnetic, electrical, wear-resistant, and corrosion-resistant properties. These superior properties make amorphous alloys promising for a wide range of applications.

[0003] The preparation of amorphous alloys typically requires extremely high cooling rates. This high cooling rate limits the glass-forming ability of amorphous alloys, thus restricting the shape and maximum size of amorphous samples. Therefore, amorphous alloys usually exist in the form of thin films, strips, filaments, or powders, significantly limiting their application in practical engineering. With technological advancements, laser cladding technology, as an emerging surface engineering technique, has attracted considerable attention. This technology rapidly heats and melts alloy powder and the substrate surface under laser irradiation, causing a metallurgical bond between the substrate and the alloy powder to form a surface coating. Therefore, using surface coating technology to prepare amorphous coatings on substrate surfaces can not only reduce costs but also significantly improve the application of amorphous alloys. Currently, there are many types of amorphous alloys, such as Fe-based, Ni-based, Zr-based, Al-based, Co-based, Cu-based, and Pd-based alloys. However, due to the high cost of Co, Zr, and Pd-based amorphous metals, they are only suitable for a few special applications. Therefore, people have turned their attention to traditional iron-based amorphous alloys and found that they have excellent properties in terms of mechanics, magnetism, wear resistance and corrosion resistance. Moreover, the raw materials for production are inexpensive and readily available, which makes them cost-effective and has made them one of the hot research topics in the field of coatings.

[0004] Currently, there are many patents on the application of laser cladding to prepare iron-based amorphous coatings. For example, [Patent: CN 101899663A] uses a mixture of elements as the original powder for cladding and performs laser cladding under an argon protective atmosphere to prepare an iron-based amorphous nanocrystalline coating; [Patent: CN 103302287A] uses alloy powder containing Mo, Nb, Co and rare earth elements Ce and Y for cladding to finally obtain an iron-based amorphous composite coating with an amorphous content of 30%; [Patent: CN 107442778A] uses raw materials Fe, Cr, Mo, C and FeB to prepare iron-based amorphous powder for 3D printing through melting and gas atomization. The iron-based amorphous coatings obtained by using existing amorphous powders are not completely amorphous, which greatly affects the wear resistance and corrosion resistance of the coating. Furthermore, many patents have not yet mentioned the influence of powder particle size on the amorphous content and forming quality of laser cladding. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a method for preparing iron-based amorphous powder suitable for synchronous powder feeding laser cladding coatings, which has good forming quality and high amorphous forming capability.

[0006] This invention provides a method for preparing iron-based amorphous alloy powder. Using the prepared iron-based amorphous alloy powder as raw material, an iron-based amorphous alloy coating is prepared using synchronous powder feeding laser cladding technology. The key feature is that, using the original iron-based powder of this invention and the laser cladding process of this invention, a coating with an amorphous content greater than 90% can be prepared.

[0007] The raw material formulation of the iron-based amorphous powder material of the present invention includes the following chemical composition in atomic percentage: Co: 10-15%, Cr: 5-10%, Mo: 35-40%, C: 0.2-0.4%, B: 0.2-0.5%, Y: 0.2-0.5%, Al: 0.2-0.6%, and the balance being Fe.

[0008] Specifically preferred, the raw materials include the following atomic percentages: 12.2% cobalt (Co); 7.4% chromium (Cr); 37.3% molybdenum (Mo); 0.3% carbon (C); 0.5% boron (B); 0.4% yttrium (Y); 0.4% aluminum (Al); with the balance being iron (Fe), for a total atomic percentage of 100%.

[0009] The specific steps include the following: First, weigh out 99.9% pure cobalt, 99.9% pure chromium, 99.9% pure molybdenum, 99% pure boron carbide powder, 99.9% pure yttrium, and 99% pure iron. Place all raw materials into an induction heating melting furnace and remelt them six times to ensure uniform composition. Atomize the molten metal gas to prepare iron-based amorphous powder, and screen out powder with a particle size of less than 45μm as raw material for laser cladding.

[0010] The second step involves using the following synchronous powder feeding laser cladding process parameters: laser power 2000-3000W, scanning speed 1500-3000mm / min, powder feeding speed 20-30g / min, spot diameter 3-5mm, synchronous three-beam powder feeding head, and powder focused 1-2mm above the substrate.

[0011] The third step is to polish the substrate surface to a metallic luster, then perform surface cleaning treatment, and finally apply an iron-based amorphous coating under argon protection.

[0012] The iron-based amorphous powder of the present invention has high laser forming quality, can be clad on steel materials such as carbon steel and pipeline steel, and the prepared coating has high glass forming ability.

[0013] The method for preparing iron-based amorphous powders in this invention is efficient, practical, and easy to prepare, making it suitable for large-scale industrial and commercial production.

[0014] The iron-based amorphous powder preparation scheme and synchronous powder feeding laser cladding process parameters provided by this invention result in a crack-free coating with high amorphous content, strong wear resistance and corrosion resistance. Its characteristics are: the coating thickness is 100-1000μm, the coating surface is smooth, there are no macroscopic cracks, and it has an amorphous content of more than 90%. Attached Figure Description

[0015] Figure 1 Electron scanning microscope images (a) and (b) of the iron-based amorphous powder in Example 1;

[0016] Figure 2 XRD pattern of synchrotron laser cladding iron-based amorphous powder;

[0017] Figure 3 Image (a) of the cross-sectional microstructure of the laser-clad iron-based amorphous coating and XRD pattern of the iron-based amorphous coating surface (b);

[0018] Figure 4 The graph shows the micro Vickers hardness measurement results of laser-clad iron-based amorphous coatings. Detailed Implementation

[0019] To make the technical solution and implementation of the present invention clearer, the following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the invention.

[0020] Example 1

[0021] The specific method for preparing iron-based amorphous alloy powder and its simultaneous powder feeding laser cladding iron-based amorphous coating is as follows:

[0022] (1) Weigh and prepare the materials using the following elements and atomic percentages to calculate the corresponding mass of each element: 12.2% cobalt (Co); 7.4% chromium (Cr); 37.3% molybdenum (Mo); 0.3% carbon (C); 0.5% boron (B); 0.4% yttrium (Y); 0.4% aluminum (Al); with the balance being iron (Fe), and the atomic percentage being 100%.

[0023] (2) The raw materials used are 99.9% pure cobalt, 99.9% pure chromium, 99.9% pure molybdenum, 99% pure boron carbide powder, 99.9% pure yttrium and 99% pure iron.

[0024] (3) A vacuum induction melting furnace was used to heat the raw materials into a molten state, and the process was repeated 6 times to ensure uniform composition. The molten metal was then directly atomized to prepare iron-based amorphous alloy powder. Powder with a particle size of less than 45 μm was selected as the raw material for laser cladding, with an amorphous content of 100%.

[0025] (4) 45 steel with dimensions of 200mm×200mm×10mm was selected as the substrate; sandpaper was used to remove oxides from the substrate surface; anhydrous ethanol was used for ultrasonic cleaning to remove wear debris and oil stains from the substrate surface. The synchronous powder feeding laser cladding process parameters used were: laser power 3000W, scanning speed 2500mm / min, powder feeding speed 20g / min, spot diameter 3.5mm, synchronous three-beam powder feeding head, and powder focused 1mm above the substrate to prepare an iron-based amorphous coating.

[0026] SEM images and particle size distribution statistics of the iron-based amorphous powder prepared in this embodiment are as follows: Figure 1 As shown in the figure, most of the powder is spherical. This powder has excellent flowability and filling properties. The flowability of the powder measured by a Hall effect flowmeter is 13.4 g / 50 g, which is very suitable as a powder for synchronous powder feeding laser cladding.

[0027] The X-ray diffraction pattern of the iron-based amorphous alloy powder of the present invention is as follows: Figure 2 As shown in the figure, it can be observed that the powder sample exhibits a diffuse diffraction peak characteristic of amorphous materials near 2θ of 45 degrees, with a span of 10 degrees, indicating that the powder is completely amorphous.

[0028] Using the aforementioned iron-based amorphous powder as the raw material for laser cladding, an iron-based amorphous coating was prepared using a laser and a CNC control system. The coating structure was uniform, with few pores, no unfused particles, and good adhesion to the substrate. Figure 3 As shown in (a), the coating has a very high amorphous content. XRD patterns of the coating surface are shown in [image missing]. Figure 3 As shown in (b), the XRD pattern of the coating shows that it is mainly an amorphous phase.

[0029] The hardness values ​​of the iron-based amorphous coating and substrate were measured using a Vickers microhardness tester HVS-1000A. A pressure of 200g was applied for 15 seconds. During the test, efforts were made to avoid errors caused by testing near defects such as pores. For each point on each sample, three hardness values ​​were measured at different areas of the same location, and the average value was taken for each test point. The microhardness curves are shown below. Figure 4 As shown.

Claims

1. An iron-based amorphous powder suitable for use in a simultaneous powder-fed laser cladding coating, characterized in that, The atomic percentage of the chemical composition of the iron-based amorphous powder is Co: 10-15%, Cr: 5-10%, Mo: 35-40%, C: 0.2-0.4%, B: 0.2-0.5%, Y: 0.2-0.5%, Al: 0.2-0.6%, and the balance is Fe; The raw materials are weighed according to the atomic percentage of the chemical composition of the iron-based amorphous powder, the raw materials are smelted by using a vacuum induction smelting furnace, and the powder is prepared by gas atomization of the molten metal.

2. The iron-based amorphous powder suitable for simultaneous powder-fed laser cladding coating according to claim 1, characterized in that, The atomic percentage of the chemical composition of the iron-based amorphous powder is Co: 12.2%, Cr: 7.4%, Mo: 37.3%, C: 0.3%, B: 0.5%, Y: 0.4%, Al: 0.4%, and the balance is Fe.

3. The iron-based amorphous powder suitable for simultaneous powder-fed laser cladding coating according to claim 1, characterized in that, The particle size of the iron-based amorphous powder is 45 microns, and the amorphous content is 100%.

4. The method for the preparation of iron-based amorphous powder suitable for simultaneous powder-fed laser cladding coating according to claim 1, characterized in that, Further comprising: The powder is screened to have a particle size of 45 microns.

5. The method for the preparation of iron-based amorphous powder suitable for simultaneous powder-fed laser cladding coating according to claim 1, characterized in that, The raw materials are: pure cobalt with a purity of 99.9%, pure chromium with a purity of 99.9%, pure molybdenum with a purity of 99.9%, boron carbide powder with a purity of 99%, pure yttrium with a purity of 99.9%, and iron with a purity of 99%.

6. The method for the preparation of iron-based amorphous powder suitable for simultaneous powder-fed laser cladding coating according to claim 1, characterized in that, The vacuum induction smelting furnace smelts the raw materials for six times of repeated remelting.

7. A method of producing a synchronously fed laser cladded coating, characterized in that Under the protection of an inert gas atmosphere, the iron-based amorphous powder of any one of claims 1-3 is laser cladded on the surface of a substrate by using a synchronous powder feeding laser.

8. The method of claim 7, wherein the method further comprises, The substrate is steel.

9. The method of claim 7, wherein the method further comprises, The process parameters of the synchronous powder feeding laser cladding are: laser power 2000-3000 W, scanning speed 1500-3000 mm / min, powder feeding speed 20-30 g / min, spot diameter 3-5 mm, synchronous three-beam powder feeding head, and the iron-based amorphous powder is focused at a position 1-2 mm above the substrate. The substrate is steel.

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