NL2030746B1

NL2030746B1 - METHOD FOR PREPARING IN-SITU SYNTHESIZED Al-Fe-Si TERNARY CERAMICS/FE-BASED COMPOSITE COATING BY LASER IRRADIATION

Info

Publication number: NL2030746B1
Application number: NL2030746A
Authority: NL
Inventors: Li Baoxing; Liu Dejia; Hu Yong; Zhao Longzhi; Zhao Mingjuan; Tang Yanchuan; Yu Meng; Guan Yumeng; Jiao Haitao; Lin Xiaoxue; Cheng Ziwei
Original assignee: Univ East China Jiaotong
Priority date: 2022-01-27
Filing date: 2022-01-27
Publication date: 2023-03-20
Also published as: NL2030746A

Abstract

The disclosure provides a method for preparing an z'n-situ synthesized Al-Fe-Si ternary ceramics/Fe-based composite coating by laser irradiation, including the following steps: conducting irradiation on a composite powder of Al, Si and Fe and a substrate through a laser beam using Q235 as the substrate under the protection of an argon gas and a helium gas, to form an Al-Fe-Si ternary ceramics/Fe-based composite coating. In the composite powder, the Fe, the Al and the Si have a ratio of 6:1:3 to 18:1:3, and the irradiation is conducted at a laser spot diameter of 0.5-4 mm, a power of LOGO-2,500 W and a scanning rate of 200-600 mm/min. The present disclosure has the advantages as follows: the coating obtained by the preparation method has extremely ﬁrm metallurgical bonding with the substrate, which is not easy to peel off, the coating also has a smooth surface, no internal cracks and porosity defects.

Description

METHOD FOR PREPARING IN-SITU SYNTHESIZED Al-Fe-Si TERNARY

CERAMICS/FE-BASED COMPOSITE COATING BY LASER IRRADIATION

TECHNICAL FIELD

[01] The present disclosure relates to a preparation method of a composite coating, in particular to a method for preparing an in-situ synthesized Al-Fe-Si ternary ceramics/Fe- based composite coating by laser irradiation.

BACKGROUND ART

[02] Composite coating with brand-new properties is prepared by depositing two or more materials with different properties on a surface of a substrate through physical or chemical methods. Various materials composed of the composite coating complement and coordinate with each other in performance, such that the composite coating has a comprehensive performance better than that of the original materials to meet requirements of various working conditions. Therefore, composite coatings have broad prospects for use in surface repair and enhancement of key components in aerospace, machinery manufacturing, metallurgy and automobile industries.

[03] According to an addition method of a reinforcement of the composite coatings, composite coatings are mainly prepared by an external adding method and an in-situ synthesis method. For a long time, the composite coatings are prepared focused on traditional thermal spraying and surfacing methods; coatings prepared by such methods have poor bonding with substrates, poor coating quality and short coating life. Moreover, reinforcements in the coatings prepared by the external reinforcement method have poor wettability and poor interface bonding with the coating substrate. Laser surface modification technology, as a novel local surface modification method, has a high laser beam energy density, small substrate heat-affected zone, strong process controllability and high speed. This method can efficiently prepare composite coatings. /n-situ synthesized composite coatings having desirable metallurgical bonding with the substrates can be prepared by laser irradiation, and an in-situ reinforcement is formed by reaction in a coating substrate. The reinforcement has desirable compatibility with the coating substrate to improve the hardness, wear resistance, heat resistance, corrosion resistance and fatigue resistance of the material surfaces, thereby improving the service life of workpieces. This method has become a development direction of novel composite coatings.

SUMMARY

[04] A purpose of the present disclosure is to provide a method for preparing an in-situ synthesized Al-Fe-Si ternary ceramics/Fe-based composite coating by laser irradiation. A composite coating prepared by the method has extremely firm metallurgical bonding with a substrate material, which is not easy to peel off; the cladding layer has a smooth surface, no internal cracks and porosity defects, and the composite coating has significantly- improved hardness and wear resistance on a surface.

[05] The present disclosure provides a method for preparing an in-situ synthesized Al-

Fe-Si ternary ceramics/Fe-based composite coating by laser irradiation, including the following steps: pre-treating a surface of a substrate: roughening the substrate to remove oxides and rust stains on the surface to make the substrate easy to form a firm bond with a coating; cleaning a surface of a roughened substrate with an organic solvent, followed by drying with a hair dryer or air-drying naturally; mixing a Fe powder, an Al powder and a

Si powder that have a certain particle size fully in a mixer at a certain proportion, and subjecting a mixed AI-Fe-Si powder to scanning and irradiation under the protection of an argon gas or a helium gas with a laser under appropriate process parameters, to form an in- situ synthesized Al-Fe-Si ternary ceramics/Fe-based composite coating; and conducting metallurgical bonding on the coating and the substrate.

[06] In the present disclosure, the Fe powder, the Al powder and the Si powder may have a particle size of 300-100 mesh and a mass ratio of 6:1:3 to 18:1:3.

[07] In the present disclosure, the scanning and irradiation may be conducted at a laser spot diameter of 0.5-4 mm, a power of 1,000-2,500 W and a scanning rate of 200-600 mm/min under the protection of the argon gas or the helium gas.

[08] In the present disclosure, the Al-Fe-Si ternary ceramics/Fe-based composite coating may be eventually formed.

[09] In the present disclosure, the roughening may be conducted by sandblasting or sanding the surface. The organic solvent may be acetone or anhydrous ethanol.

[10] In the present disclosure, based on rapid heating and rapid cooling of the laser, the optimal coating composition and process parameters are selected through the scientific design of coating composition and the optimization of process parameters during laser cladding, and coatings with optimal performance are in-situ prepared on the substrate.

[11] The present disclosure has the advantages as follows: (1) the coating prepared by the method has extremely firm metallurgical bonding with the substrate, which is not easy to peel off; the coating has a smooth surface, no internal cracks and porosity defects; (2)

the laser as a clean energy does not pollute the environment; a laser energy and a scanning rate can be precisely controlled; the preparation process is simple, green, clean and environment-friendly, which is conducive to industrial production automation; (3) the substrate of the in-situ synthesized Al-Fe-Si ternary ceramics/Fe-based composite coating 5S prepared by the method has desirable compatibility with the in-situ synthesized Al-Fe-Si ternary ceramics reinforcement, and the composite coating has a clean interface and an excellent performance. The composite coating has a hardness 4 times that of the substrate, and a wear resistance increased to 3.5 times. The present disclosure is an effective means for improving surface hardness and wear resistance of the materials, with a desirable prospect for use and economic significance.

BRIEF DESCRIPTION OF THE DRAWINGS

[12] FIG. 1 shows a microstructure diagram of a composite coating of Example 1 of the present disclosure;

[13] FIG. 2 shows an X-ray diffraction (XRD) analysis pattern of a phase analysis of a cladding layer of Example 2 of the present disclosure;

[14] FIG. 3 shows hardness of composite coatings prepared in Example 1, Example 2 and Example 3 of the present disclosure; and

[15] FIG. 4 shows relative abrasion resistance of the composite coatings prepared in

Example 1, Example 2 and Example 3 of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[16] Example 1

[17] Sandblasting was conducted on a surface of a substrate Q235 steel with a sandblasting machine to remove a rust layer and oxides on the surface, to obtain a surface with a relatively high surface roughness; a surface of a roughened Q235 steel was washed with an acetone solution until the surface was clean and free of oil stains, followed by air- drying naturally for later use. A 200-mesh Fe powder, a 200-mesh Al powder and a 200- mesh Si powder were mixed in a mixer at a ratio of 6:1:3 for 3 h, such that the Fe powder, the Al powder and the Si powder were fully mixed to obtain an Al-Fe-Si composite powder. The Q235 steel was put on a worktable of a laser, a prefabricated composite powder was set on a substrate, followed by irradiation and scanning with the laser at a laser power of 1,600 W, a scanning rate of 400 mm/min and a spot diameter of 4 mm.

[18] Example 2

[19] Sandblasting was conducted on a surface of a substrate Q235 steel with a sandblasting machine to remove a rust layer and oxides on the surface, to obtain a surface with a relatively high surface roughness; a surface of a roughened Q235 steel was washed with an acetone solution until the surface was clean and free of oil stains, followed by air- 5S drying naturally for later use. A 200-mesh Fe powder, a 200-mesh Al powder and a 200- mesh Si powder were mixed in a mixer at a ratio of 8:1:1 for 3 h, such that the Fe powder, the Al powder and the Si powder were fully mixed to obtain an Al-Fe-Si composite powder. The Q235 steel was put on a worktable of a laser, a prefabricated composite powder was set on a substrate, followed by irradiation and scanning with the laser at a laser power of 1,600 W, a scanning rate of 400 mm/min and a spot diameter of 4 mm.

[20] Example 3

[21] Sandblasting was conducted on a surface of a substrate Q235 steel with a sandblasting machine to remove a rust layer and oxides on the surface, to obtain a surface with a relatively high surface roughness; a surface of a roughened Q235 steel was washed with an acetone solution until the surface was clean and free of oil stains, followed by air- drying naturally for later use. A 200-mesh Fe powder, a 200-mesh Al powder and a 200- mesh Si powder were mixed in a mixer at a ratio of 7:1:2 for 3 h, such that the Fe powder, the Al powder and the Si powder were fully mixed to obtain an Al-Fe-Si composite powder. The Q235 steel was put on a worktable of a laser, a prefabricated composite powder was set on a substrate, followed by irradiation and scanning with the laser at a laser power of 1,600 W, a scanning rate of 400 mm/min and a spot diameter of 4 mm.

[22] FIG. 1 shows a microstructure of the composite coating prepared in Example 1. It can be seen from the figure that the surface of the coating is smooth and free of macroscopic cracks and pore defects; and the coating has uniform and fine grains, which is inline with the characteristics of excellent coatings.

[23] FIG. 2 shows an XRD composition diagram of the composite coating prepared in

Example 2. As can be seen from the figure, the coating is mainly composed of a Fe substrate and an in-situ synthesized AlsFe;Si4 ternary ceramics reinforcement.

[24] FIG. 3 shows a hardness curve of the composite coatings obtained in Example 1,

Example 2 and Example 3. It can be seen from the figure that the coatings prepared in the three examples each have a greatly improved hardness, where the coating in Example 2 has the highest hardness reaching 556 HV, which is about 4 times that of the substrate material.

[25] FIG. 4 shows a relative wear resistance curve of the composite coatings obtained in Example 1, Example 2 and Example 3. It can be seen from the figure that the coatings prepared in the three examples each have correspondingly improved relative wear resistance, where the coating in Example 2 has the highest relative wear resistance reaching 4 times, which is about 3.5 times that of the substrate material. This proves that 5 the Al-Fe-Si ternary ceramics/Fe-based composite coating prepared in situ by laser irradiation has a desirable wear resistance.

[26] In summary, the reinforcement and the substrate of the Al-Fe-Si ternary ceramics/Fe-based composite coating prepared by the method of the present disclosure has a clean interface and desirable compatibility; the composite coating has excellent performance and long service life; the production process is simple, green, clean and environmental-friendly, which is conducive to the industrial production automation.

Claims

Conclusions l. Method for preparing an in-situ fabricated composite coating based on Al-Fe-Si ternary ceramic/Fe by laser irradiation, comprising the following steps: pre-treating a surface of a substrate: roughening the substrate to remove oxides and remove rust stains on the substrate to make it easy for the substrate to form a firm bond with a top coat; cleaning a surface of a roughened substrate with an organic solvent, followed by blow drying or natural air drying; completely mixing a Fe powder, an Al powder and a Si powder of a certain particle size in a mixer in a certain ratio, and subjecting a composite Al-Fe-Si powder to scanning and irradiation under the protection of an argon gas or a helium gas with a laser under appropriate process parameters to form an in-situ fabricated composite coating based on Al-Fe-Si ternary ceramic/Fe; and performing metallurgical bonding on the coating and the substrate.

The method for preparing an in-situ fabricated composite coating based on Al-Fe-Si ternary ceramic/Fe by laser irradiation according to claim 1, wherein the Fe powder, the Al powder and the Si powder have a particle size of 100 — 300 mesh and a mass ratio of 6:1:3 — 18:1:3.

The method for preparing an in-situ fabricated composite coating based on Al-Fe-Si ternary ceramic/Fe by laser irradiation according to claim 1, wherein the scanning and irradiation are performed with a laser spot diameter of 0.5 - 4 mm , a power of 1,000 — 2,500 W and a scanning speed of 200 — 600 mm/min under the protection of the argon gas or the helium gas.

The method for preparing an in-situ fabricated composite coating based on Al-Fe-Si ternary ceramic/Fe by laser irradiation according to claim 1, wherein the composite coating based on Al-Fe-Si ternary ceramic/ Fe is eventually formed.