CN-121992394-A - Laser cladding metal silicide ceramic coating and preparation method and application thereof

Abstract

The invention relates to the technical field of metal material surface modification, in particular to a laser cladding metal silicide ceramic coating and a preparation method and application thereof. The invention adopts the design of a 'transition layer and functional layer' dual-gradient high-entropy alloy coating, and sequentially prepares Fe-Cr-Ni-Co-Si high-entropy alloy with low Si content and high Si content on the surface of a steel substrate by a laser cladding technology as a transition layer and a functional layer respectively, and then realizes the transformation of a uniform eutectic phase (Fe-Cr-Ni-Co) 3 Si metal silicide phase through heat treatment. The transition layer can relieve interface stress and avoid cracking and peeling of the coating, and the functional layer takes (Fe-Cr-Ni-Co) 3 Si as a main phase, has high wear resistance, corrosion resistance and high temperature stability, and has no cracking risk caused by Ti/Al doping. The coating prepared by the invention is suitable for the severe working condition of the high-temperature blade of the high-temperature furnace, can obviously prolong the service life of the blade, and has wide industrial application prospect.

Inventors

• QIU HAO
• WU LIHUA
• FENG QING
• MA RUCHENG
• Zhu Jiangqi
• LU BINGWEN
• Yan xingchen

Assignees

• 广东开放大学（广东理工职业学院）
• 广东省科学院新材料研究所

Dates

Publication Date

20260508

Application Date

20260128

Claims (10)

1. 1. The laser cladding metal silicide ceramic coating is characterized by comprising a transition layer and a functional layer; The transition layer and the functional layer are both Fe-Cr-Ni-Co-Si high-entropy alloy coatings; In the transition layer, the atomic percentage of Si is 5-10%; in the functional layer, the atomic percentage of Si is 23% -27%.
2. 2. The laser cladding metal silicide ceramic coating of claim 1, wherein in the transition layer, the atomic percentage of Si is 5-10%, the balance being Fe, cr, ni and Co, the atomic ratio of Fe, cr, ni and Co being 1:1:1, the atomic percentage of Si in the functional layer being 23% -27%, the balance being Fe, cr, ni and Co, the atomic ratio of Fe, cr, ni and Co being 1:1:1.
3. 3. The laser cladding metal silicide ceramic coating according to claim 1, wherein the thickness of the transition layer is 0.3-0.8 mm, and the thickness of the functional layer is 1.0-2.0 mm.
4. 4. A method of producing a laser cladding metal silicide ceramic coating as claimed in any one of claims 1 to 3, comprising the steps of: Preparing high-entropy alloy powder required by a transition layer and a functional layer respectively, preparing the transition layer on the surface of a substrate in a laser cladding mode, preparing the functional layer on the surface of the transition layer in a laser cladding mode to obtain a clad substrate, heating the clad substrate, and performing heat treatment to obtain the laser cladding metal silicide ceramic coating.
5. 5. The method of claim 4, wherein the preparing the high entropy alloy powder required for the transition layer and the functional layer respectively comprises: adding Si powder into the Fe-Cr-Ni-Co quaternary alloy powder to obtain first mixed powder, controlling the atomic percentage of Si in the first mixed powder to be 5-10%, and performing ball milling treatment to obtain high-entropy alloy powder required by a transition layer; Adding Si powder into the Fe-Cr-Ni-Co quaternary alloy powder to obtain second mixed powder, controlling the atomic percentage of Si in the second mixed powder to be 23-27%, and performing ball milling treatment to obtain the high-entropy alloy powder required by the functional layer.
6. 6. The method according to claim 5, wherein the atomic ratio of Fe, cr, ni and Co in the Fe-Cr-Ni-Co quaternary alloy powder is 1:1:1:1, the particle size of the Fe-Cr-Ni-Co quaternary alloy powder is 53-150 μm, and the particle size of the Si powder is 50-100 μm.
7. 7. The method according to claim 5, wherein the rotation speed of the ball milling treatment is 200-300r/min, and the time of the ball milling treatment is 2-4h.
8. 8. The preparation method of the ceramic material according to claim 4, wherein the substrate is 2Cr13 stainless steel or 20G boiler steel, the laser power is 1500-180W when the transition layer is prepared on the surface of the substrate by means of laser cladding, the laser scanning speed is 600-900 mm/min, and the laser power is 2000-2400W when the functional layer is prepared on the surface of the transition layer by means of laser cladding, and the laser scanning speed is 600-900 mm/min.
9. 9. The method according to claim 4, wherein the rate of temperature rise is 5 to 10 ℃ per minute, the temperature of the heat treatment is 850 to 950 ℃, and the time of the heat treatment is 2 to 4 hours.
10. 10. Use of a laser cladding metal silicide ceramic coating as claimed in any one of claims 1-3 in the manufacture of high temperature furnace high temperature blades.

Description

Laser cladding metal silicide ceramic coating and preparation method and application thereof Technical Field The invention relates to the technical field of metal material surface modification, in particular to a laser cladding metal silicide ceramic coating and a preparation method and application thereof. Background The high-temperature (blast furnace gas residual pressure turbine power generation device) blade is a core component in a high-temperature furnace system, is in long-term service in a high-temperature (generally 400-800 ℃) and dust-containing and corrosive furnace gas environment, and is subjected to severe friction abrasion and medium corrosion, so that the surface of the blade is invalid, the service life is shortened, frequent shutdown and replacement are required, the production efficiency is affected, and the operation and maintenance cost is increased. The high-entropy alloy shows excellent corrosion resistance and high-temperature stability due to the synergistic effect of multiple principal elements, however, the high-entropy alloy has low hardness (HV is less than or equal to 300) and insufficient wear resistance, is easy to generate adhesive wear and abrasive particle wear under the high-temperature friction working condition, and cannot meet the long-term wear-resistant requirement of the high-temperature blade. In the prior art, in order to improve the wear resistance of Fe-Cr-Ni-Co high-entropy alloy, a mode of doping Ti, al and other elements is generally adopted, and the hardness and the wear resistance are improved by forming intermetallic compound reinforced phases. However, the atomic radiuses of Ti and Al have larger difference with the matrix elements, the brittleness of intermetallic compounds is higher, cracks are difficult to control in the coating preparation process, the bonding strength and the service life of the coating are seriously influenced, and the popularization and the application of the coating on key parts such as high-temperature blades are limited. Metal silicide (e.gAnd the like) has high hardness (HV is more than or equal to 800), excellent high-temperature wear resistance and high-temperature oxidation resistance, and the atomic radius matching property of Si and Fe, cr, ni, co is good, so that obvious lattice distortion is not easy to generate after doping. However, when the Fe-Cr-Ni-Co-Si high-entropy alloy coating with high Si content is directly prepared on the surface of the steel substrate, the coating is easy to crack and peel due to larger difference of thermal expansion coefficients of the coating and the substrate, and meanwhile, the coating with high Si content needs to form a eutectic phase in the laser cladding process, which is the key for avoiding cracking in the cladding process, because the grain boundary can buffer a part of stress. Therefore, how to realize firm combination of the coating and the matrix and formation of uniform and stable metal silicide phase on the premise of avoiding cracking defects through reasonable coating design and process regulation becomes a key for solving the problem of wear resistance and crack resistance of the high-temperature blade. Disclosure of Invention In order to solve the technical problems in the prior art, the invention aims to provide a laser cladding metal silicide ceramic coating to solve the technical problems. The invention aims to overcome the defects that the existing Fe-Cr-Ni-Co-Si high-entropy alloy coating has insufficient wear resistance and is easy to crack during Ti and Al doping strengthening, and provides a preparation method of a laser cladding metal silicide ceramic coating and a high-temperature blade, through the design of the gradient high-entropy alloy coating and the heat treatment process, the firm combination of the coating and the matrix is realized, the (Fe-Cr-Ni-Co) 3 Si phase functional layer which is free of cracking and uniform is obtained, the high wear resistance, the corrosion resistance, the high-temperature stability and the crack resistance are considered, and the severe working condition of the high-temperature blade is adapted. In order to achieve the above purpose, the present invention adopts the following technical scheme. According to a first aspect of the invention, the invention provides a laser cladding metal silicide ceramic coating, which comprises a transition layer and a functional layer; The transition layer and the functional layer are both Fe-Cr-Ni-Co-Si high-entropy alloy coatings (the transition layer is Fe-Cr-Ni-Co-Si high-entropy alloy with low Si content, and the functional layer is Fe-Cr-Ni-Co-Si high-entropy alloy with high Si content); In the transition layer, the atomic percentage of Si is 5-10%; in the functional layer, the atomic percentage of Si is 23% -27%. The transition layer and the functional layer form a gradient structure. In some embodiments, the atomic percentage of Si is 5-8%. One surface of the transition layer is conne