CN111004990B

CN111004990B - MAX phase coating for thermal barrier coating anti-melting CMAS corrosion and thermal spraying preparation method

Info

Publication number: CN111004990B
Application number: CN201911230401.5A
Authority: CN
Inventors: 郭磊; 颜正
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2019-12-04
Filing date: 2019-12-04
Publication date: 2022-07-08
Anticipated expiration: 2039-12-04
Also published as: CN111004990A

Abstract

The invention relates to a MAX phase coating for resisting molten CMAS corrosion of a thermal barrier coating and a thermal spraying preparation method; the thermal barrier coating system using MAX phase ceramic coating as corrosion protective layer includes alloy base body, bonding layer, YSZ ceramic layer, MAX phase ceramic layer and its preoxidation layer. Firstly preparing MAX phase Ti for thermal spraying₂AlC or Ti₃AlC₂Powder or suspension with particle size of 10-100 μm, wherein the suspension is water-based or ethanol-based and neutral or acidic; then preparing by adopting a supersonic flame spraying or suspension plasma spraying or plasma spraying-physical vapor deposition method; then, heat treatment is carried out to form a pre-oxidation layer on the surface. The thickness of the prepared ceramic layer is 10-20 mu m, and the porosity is 3-10%. The thermal barrier coating containing the MAX phase coating and resisting the corrosion of the molten CMAS is used for surface protection of the hot end component of the aero-engine, and can effectively improve the adaptability of the hot end component in severe high-temperature and corrosive environments.

Description

MAX phase coating for thermal barrier coating anti-melting CMAS corrosion and thermal spraying preparation method

Technical Field

The invention belongs to the technical field of thermal barrier coatings, and particularly relates to a corrosion protection layer for resisting CMAS corrosion of environmental sediments of a YSZ thermal barrier coating and a thermal spraying preparation method thereof; in particular to a MAX phase coating for resisting the corrosion of molten CMAS of a thermal barrier coating and a thermal spraying preparation method.

Background

Thermal Barrier Coatings (TBCs) are one of the core technologies of turbine blades of aeroengines, and the technology is to compound high-temperature-resistant, low-heat-conductivity and corrosion-resistant ceramic materials onto a base metal in the form of a coating so as to prolong the temperature of the surface of a hot-end part and prolong the service life of engine components by reducing the temperature of the hot-end partThe service life of the engine is prolonged, and the operating temperature of the engine is increased, so that the heat efficiency and the performance of the engine are obviously improved. The harsh working environment requires the thermal barrier coating to have a complex multilayer structure, and the classical thermal barrier coating consists of a high-temperature alloy substrate, a bonding layer and a ceramic layer. Due to 6-8 wt% of Y₂O₃Stabilized ZrO₂The YSZ has excellent comprehensive performance (has the performances of lower thermal conductivity, larger thermal expansion coefficient, higher fracture toughness and the like), and becomes the most widely applied thermal barrier coating ceramic layer material at present.

However, with increasing engine service temperatures, YSZ thermal barrier coatings face severe challenges, especially coating failure induced by environmental deposits. When the airplane is in service in desert airlines or areas with frequent volcanic activity, the aircraft engine can suck environmental sediments carried in air inflow, such as sand grains, dust, volcanic ash or other silicon-containing debris, and the main components of the sediments are CaO-MgO-Al₂O₃-SiO₂(CMAS for short). CMAS can cause fatal damage to thermal barrier coatings. At low temperatures, CMAS particles scour and abrade the thermal barrier coating surface; at high temperature (more than 1250 ℃), CMAS adheres to the surface of the thermal barrier coating, and permeates into the coating after melting, thereby accelerating the peeling of the coating from two aspects of thermochemistry and thermodynamics. Wherein, thermochemical damage means that the CMAS melt can dissolve YSZ grains, resulting in ZrO₂The loss stabilizer has unfavorable phase change, and high-value stress is accumulated in the coating; thermodynamic damage refers to the ability of the infiltrated liquid CMAS to fill the open structure (pores, cracks) of the coating, densify the coating, and reduce the strain tolerance of the coating to induce cracking. Therefore, development of CMAS corrosion protection of the thermal barrier coating becomes a research hotspot and difficulty in the field of the current thermal barrier coating.

Research shows that the corrosion protection layer prepared on the surface of the thermal barrier coating can effectively reduce the corrosion of CMAS, and the mechanism is that the corrosion protection layer components can react with molten CMAS to generate a compact crystalline layer to prevent the CMAS from permeating. Among them, most studied is Al₂O₃A barrier layer which has excellent CMAS resistance because it can form a dense anorthite layer by reacting with CMAS, however, due to Al₂O₃Mismatch of thermal expansion coefficients of the cladding and the YSZ coating tends to result in Al₂O₃Premature delamination of the layers during thermal cycling has limited the application of this method (see ref.1: Mohan P, Yao B, Patterson T, Sohn Y H. surface and Coatings Technology 2009,204: 797-. Aygun et Al propose solutionizing 20 mol% Al in a YSZ coating₂O₃And 5 mol% TiO₂The CMAS corrosion resistance can be obviously improved, but corrosion experiments show that the coating is approximately half damaged by penetration (see reference 2: Aygun A, Valiev A L, Padture N P, Ma X Q. acta Materialia 2007,55: 6734-6745). The research shows that Al and Ti are beneficial elements for promoting the crystallization of the CMAS and resisting the corrosion of the CMAS, and based on the inspiration, the inventor firstly proposes to adopt Ti₂AlC is used as a CMAS corrosion protection layer of a thermal barrier coating on the one hand because it is rich in Al and Ti elements and on the other hand because it has excellent high-temperature properties and a coefficient of thermal expansion which is comparable to that of Al₂O₃Closer to the YSZ coating.

Disclosure of Invention

Aiming at the problem that the traditional YSZ thermal barrier coating is easy to be damaged by CMAS corrosion, the invention provides a novel corrosion protection layer scheme adopting an MAX phase ceramic coating as a YSZ coating and a preparation method thereof.

The first purpose of the invention is to provide a thermal barrier coating corrosion protection layer material resisting molten CMAS corrosion, wherein the protection layer material is MAX phase and comprises Ti₂AlC and Ti₃AlC₂。

The second purpose of the invention is to provide a method for preparing a MAX phase ceramic coating which is resistant to molten CMAS corrosion, comprising the steps of preparing the MAX phase ceramic coating by thermal spraying and pre-oxidation heat treatment, wherein the thermal spraying method comprises supersonic flame spraying or suspension plasma spraying or plasma spraying-physical vapor deposition.

The technical scheme of the invention is as follows:

a MAX phase coating for a thermal barrier coating to resist corrosion from molten CMAS, said MAX phase material comprising Ti₂AlC or Ti₃AlC₂。

The thickness of the prepared ceramic layer is 10-20 mu m, and the porosity is 3-10%.

The invention relates to a MAX phase coating thermal spraying preparation method for thermal barrier coating anti-melting CMAS corrosion, which comprises the following steps,

1) preparation of MAX phase Ti for thermal spraying₂AlC or Ti₃AlC₂Powder or suspension with particle size of 10-100 μm, wherein the suspension is water-based or ethanol-based and is neutral or acidic;

2) and preparing a MAX-phase ceramic layer on the surface of the YSZ ceramic layer containing the high-temperature alloy and the bonding layer by adopting a thermal spraying method, wherein the thickness of the prepared ceramic layer is 10-20 mu m, and the porosity is 3-10%.

In the step 1), Al powder is added into the MAX phase powder or the suspension, wherein the content of the added Al powder is 10-20% of the mass of the MAX phase powder.

The MAX ceramic layer is prepared by adopting a supersonic flame spraying method, a suspension plasma spraying method or a plasma spraying-physical vapor deposition method.

Preparing the MAX phase ceramic layer by using a supersonic flame spraying method, wherein H is₂:O₂The spraying distance is 120-250 mm, and the preheating temperature of the matrix is 200-450 ℃;

preparing the MAX phase ceramic layer by adopting a suspension plasma spraying method, wherein the spraying current is 350-600A, the power is 20-50 KW, the spraying distance is 40-80 mm, the Ar flow is 10-40 slpm, the He flow is 8-40 slpm, and the suspension flow is 10-25 g/min;

the MAX phase ceramic layer is prepared by adopting a plasma spraying-physical vapor deposition method, wherein the spraying power is 30-60 KW, the current is 1200-2000A, the pressure of a vacuum chamber is lower than 1mbar, the flow rate of Ar is 30-50 slpm, the flow rate of He is 40-70 slpm, and the spraying distance is 1200-1800 mm.

Carrying out heat treatment on the MAX phase coating prepared by the thermal spraying to form a pre-oxidation layer with the thickness of 1-3 μm, wherein the heat treatment system is as follows: and (3) keeping the temperature of the air atmosphere at 1200 ℃ for 5-10 h.

The molten CMAS rapidly crystallizes on the surface of the thermal barrier coating, and the melt is extremely difficult to infiltrate, so that the YSZ coating below the MAX phase ceramic layer is kept stable. The thermal barrier coating is used for surface protection of the hot end component of the aircraft engine.

The particle size of the MAX phase powder for thermal spraying is 10-100 microns, in order to ensure the purity of the MAX phase ceramic coating, Al powder is added into the MAX phase powder by adopting a ball milling method, the content of the Al powder is 10-20% of the mass of the MAX phase powder, and the mixed powder slurry is dried for later use; the powder particle size of the MAX phase suspension for thermal spraying is 10-100 microns, in order to ensure the purity of the MAX phase ceramic coating, adding Al powder into MAX phase powder by adopting a ball milling method, wherein the content of the Al powder is 10-20% of the mass of the MAX phase powder, dissolving mixed powder slurry by adopting deionized water, and adding a dispersing agent to prepare uniformly dispersed MAX phase suspension for later use;

preheating a substrate containing the YSZ coating before thermal spraying;

preparing a MAX phase ceramic coating on the surface of a YSZ ceramic coating containing a high-temperature alloy substrate and a bonding layer by adopting a thermal spraying method;

pre-oxidizing the MAX phase ceramic coating to generate an oxide layer in situ;

placing the MAX/YSZ double-ceramic-layer thermal barrier coating prepared by thermal spraying into a muffle furnace for pre-oxidation heat treatment, wherein the heat treatment process system is as follows: and (3) keeping the temperature of the air atmosphere at 1200 ℃ for 5-10 h.

The thermal barrier coating containing the MAX phase protective layer and resisting the corrosion of the molten CMAS can be used for surface protection of hot end components of an aeroengine. The adaptability of the hot end component in severe high temperature and corrosive environment can be effectively improved.

The invention has the advantages that:

CMAS corrosion experiments show that after the novel thermal barrier coating prepared by the invention undergoes CMAS corrosion for 4 hours at 1250 ℃, a dense crystalline layer with anorthite as a main component is formed on the surface of the MAX coating, and the layer completely blocks the penetration of molten CMAS. No CMAS permeation and erosion trace exists in the MAX phase coating and the YSZ coating below the MAX phase coating, which shows that the thermal barrier coating has excellent CMAS corrosion resistance;

2. the pre-oxidation layer is formed by in-situ oxidation of the MAX phase coating, the MAX phase coating and the MAX phase coating are tightly combined, and the pre-oxidation layer has good structural stability. After the MAX phase coating is oxidized at 1200 ℃ for 10h, an oxide layer with the thickness of 3 mu m is formed on the surface, and no cracks or holes exist at the interface, which indicates that the layer is well combined with the substrate. After the pre-oxidized MAX phase coating is corroded by CMAS for 4 hours at 1250 ℃, the pre-oxidized layer still almost keeps complete structure;

the MAX phase coating and YSZ coating have good thermal matching (close thermal expansion coefficient), and the MAX phase coating is not easy to peel off in the thermal cycle process.

Drawings

FIG. 1 is a schematic view of a thermal barrier coating containing a MAX phase coating for resisting corrosion of molten CMAS according to the present invention

FIG. 2 is a schematic diagram of the mechanism of the novel thermal barrier coating anti-melting CMAS corrosion provided by the invention

FIG. 3a is Ti₂The surface appearance of the AlC coating after 8h pre-oxidation at 1200 DEG C

FIG. 3b is Ti₂The section appearance of the AlC coating after 8h pre-oxidation at 1200 DEG C

FIG. 4a is the surface topography of a conventional YSZ thermal barrier coating after CMAS corrosion at 1250 ℃ for 4h

FIG. 4b is a cross-sectional view of a conventional YSZ thermal barrier coating after being subjected to CMAS corrosion at 1250 ℃ for 4 hours

FIG. 5a is a view showing the novel Ti of the present invention₂The surface appearance of the AlC/YSZ thermal barrier coating after being corroded by CMAS at 1250 ℃ for 4 hours

FIG. 5b is a view showing the novel Ti of the present invention₂The section morphology of the AlC/YSZ thermal barrier coating after CMAS corrosion at 1250 ℃ for 4h and the corresponding element distribution diagram of Si and Ca

Detailed Description

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

Example 1: preparing a thermal barrier coating resisting the corrosion of molten CMAS, wherein the coating consists of a high-temperature alloy substrate, a NiCrAlY bonding layer, a YSZ ceramic layer and Ti₂AlC ceramic layer and pre-oxide layer thereof, wherein Ti₂The AlC coating is prepared by a supersonic flame spraying method and comprises the following steps:

firstly, preparing a YSZ ceramic coating on a high-temperature alloy substrate with a NiCrAlY bonding layer.

And preparing the YSZ ceramic layer on the surface of the NiCrAlY bonding layer by adopting an atmospheric plasma spraying method. The main process parameters are as follows: spraying voltage of 60V, current of 600A, main gas Ar flow of 40slpm, H₂The flow rate is 10slpm, the powder feeding rate is 15g/min, the spraying distance is 100mm, and the thickness of the obtained YSZ ceramic layer is 150 μm.

Second, preparing Ti for supersonic flame spraying₂AlC powder.

To supply Ti₂The AlC powder was sieved through a 400 mesh sieve, and the mean particle size of the sieved powder was 38 μm as determined by a particle size analyzer. For increasing Ti content in the coating prepared₂The content of AlC adopts a ball milling normal method to Ti₂Al powder is added into AlC powder, and the content is Ti₂15% of the AlC powder by mass, Al may be present in combination with Ti₂TiC decomposed from AlC in the spraying process reacts to regenerate Ti₂AlC, on the other hand Al oxidizes to Al when heated₂O₃Can protect Ti₂The AlC does not undergo a phase change. And drying the mixed powder slurry at 120 ℃ for 10 hours for later use.

Thirdly, preparing Ti on the surface of the YSZ ceramic layer by adopting a supersonic flame spraying method₂And an AlC ceramic layer.

Supersonic flame spraying fuel gas by H₂And O₂The spray gun is cooled by compressed air in the spraying process of the mixed gas. Before spraying, the substrate with the YSZ coating is preheated, wherein the preheating temperature is 300 ℃. The main technological parameters adopted in the spraying process are as follows: h₂:O₂The gas flow rate was 40slpm, the powder feed rate was 20g/min, and the spraying distance was 200 mm. Ti prepared by adopting the parameters₂The AlC coating thickness was 15 μm. XRD analysis of the resulting coating showed Ti₂The AlC phase predominates, in addition to which Ti is present₃AlC₂TiC and Al_xTi_yEqual impurity phase due to thermal activation of Ti during spraying₂Diffusion of Al from AlC thereby resulting in Ti₂The AlC undergoes a phase change. The cross-sectional morphology shows that Ti₂The AlC coating has uniform thickness, moderate porosity and Ti inside₂AlC ply, unmelted Ti₂AlC particles and impurity phases, withThe YSZ coating is tightly combined without obvious lamination cracks.

The fourth step of subjecting Ti₂And pre-oxidizing the AlC ceramic layer to generate an oxide layer in situ.

Ti prepared by spraying supersonic flame in air atmosphere₂The AlC coating is subjected to pre-oxidation heat treatment, and the main process parameters are as follows: the temperature is 1200 ℃, and the heat preservation is carried out for 8 h. The oxidized layer has an inner continuous Al layer₂O₃Outer discontinuous TiO₂The thickness of the double-layer structure of (2) is 3 μm.

Preparation of Ti₂And the AlC/YSZ double-ceramic layer thermal barrier coating.

The novel thermal barrier coating prepared by the invention comprises an outermost MAX-phase pre-oxidation layer (1-3 mu m) and an outer MAX-phase coating (Ti in the example)₂10-20 mu m of AlC coating), an inner layer YSZ coating (100-200 mu m), a double ceramic layer, a bonding layer (50-100 mu m) and a metal substrate, and is shown in a novel thermal barrier coating structure shown in figure 1. The invention provides a MAX phase coating and a pre-oxidation layer thereof on the surface of a YSZ coating, and the high-temperature alloy, the bonding layer and the YSZ ceramic layer belong to a traditional thermal barrier coating system and are prepared by adopting the prior art, and the same is carried out in the following embodiments. After the novel thermal barrier coating provided by the invention is corroded by CMAS, a compact crystalline layer can be rapidly formed on the surface of the coating, the penetration and the corrosion of molten CMAS at high temperature are prevented, and the mechanism of resisting the corrosion of the molten CMAS is shown in figure 2.

Ti₂The surface morphology of the AlC coating after 8h pre-oxidation at 1200 ℃ is shown in FIG. 3 a. FIG. 3a shows, after pre-oxidation, Ti₂Several rod-shaped TiO are generated on the surface of AlC coating₂Grains randomly distributed in Al₂O₃On the substrate. The cross-sectional morphology (FIG. 3b) shows that the oxide layer is continuous with the inner layer of Al₂O₃And TiO discontinuous with the outer layer₂Composition, thickness about 3 μm.

Ti prepared in traditional YSZ thermal barrier coating and the invention₂CMAS powder is respectively coated on the surface of the AlC/YSZ double-ceramic-layer thermal barrier coating so as to investigate the corrosion resistance of the novel thermal barrier coating provided by the invention. The selected CMAS component is 33CaO-9MgO-13AlO_1.5-45SiO₂(molar ratio), coatingThe density is 15mg/cm²The coating sample coated with the CMAS powder was placed in a muffle furnace at 1250 ℃ for a constant temperature heat treatment for 4 h. The surface and cross-sectional topography of the YSZ coating after CMAS etching is shown in fig. 4a and 4b, respectively. FIG. 4a shows that the YSZ coating surface is coated with a very thin layer of CMAS, with no significant CMAS residue. The cross-sectional morphology (fig. 4b) shows that after the CMAS is melted, the CMAS penetrates into the coating, and permeation traces of the CMAS can be observed in a plurality of holes and cracks inside the coating, which indicates that the YSZ coating has poor CMAS erosion resistance. Ti prepared by the invention₂The surface morphology and the cross-sectional morphology of the AlC/YSZ thermal barrier coating after CMAS corrosion and the element distribution of Ca and Si are respectively shown in FIG. 5a and FIG. 5 b. FIG. 5a shows that a large amount of CMAS glass remained on the surface of the coating, and the surface of the primary oxide layer was not observed. Cross-sectional morphology (FIG. 5b) shows Ti after CMAS etching₂The AlC pre-oxide layer remains almost structurally intact with a significant amount of CMAS remaining thereon. A dense crystalline layer of anorthite as the main component was formed between CMAS and the pre-oxidized layer to a thickness of about 5 μm. EDS surface scan results of the cross section show that Si and Ca (CMAS main components) are completely blocked by the dense crystallization layer and the pre-oxidation layer and cannot penetrate into Ti₂In the AlC/YSZ thermal barrier coating, the Ti prepared by the invention is illustrated₂The AlC/YSZ thermal barrier coating has excellent CMAS corrosion resistance.

Example 2: preparing a thermal barrier coating resisting the corrosion of molten CMAS, wherein the coating consists of a high-temperature alloy substrate, a NiCrAlY bonding layer, a YSZ ceramic layer and Ti₂AlC ceramic layer and pre-oxide layer thereof, wherein Ti₂The AlC coating is prepared by a supersonic flame spraying method and comprises the following steps:

And preparing the YSZ ceramic layer on the surface of the NiCrAlY bonding layer by adopting an atmospheric plasma spraying method. The main technological parameters are as follows: spraying voltage of 60V, current of 600A, main gas Ar flow of 40slpm, H₂The flow rate is 10slpm, the powder feeding rate is 15g/min, the spraying distance is 100mm, and the thickness of the obtained YSZ ceramic layer is 150 μm.

Second, preparing Ti for supersonic flame spraying₂And (4) AlC powder.

To supply Ti₂The AlC powder was sieved through a 400 mesh sieve, and the mean particle size of the sieved powder was 38 μm as determined by a particle size analyzer. For increasing Ti content in the coating prepared₂The content of AlC adopts a ball milling normal method to Ti₂Al powder is added into AlC powder, and the content is Ti₂20% of the AlC powder by mass, in one aspect Al can be present with Ti₂TiC decomposed from AlC in the spraying process reacts to regenerate Ti₃AlC₂On the other hand, Al oxidizes to Al when heated₂O₃Can protect Ti₂The AlC does not undergo a phase change. And drying the mixed powder slurry at 120 ℃ for 10 hours for later use.

Supersonic flame spraying fuel gas by H₂And O₂The spray gun is cooled by compressed air in the spraying process of the mixed gas. Before spraying, the substrate with YSZ coating is preheated, and the preheating temperature is 450 ℃. The main technological parameters adopted in the spraying process are as follows: h₂:O₂The gas flow rate was 50slpm, the powder feed rate was 25g/min, and the spraying distance was 120 mm. Ti prepared by adopting the parameters₂The AlC coating thickness was 20 μm. XRD analysis of the resulting coating showed Ti₂The AlC phase predominates, in addition to which Ti is present₃AlC₂TiC and Al_xTi_yEqual impurity phase due to thermal activation of Ti during spraying₂Diffusion of Al from AlC resulting in Ti₂The AlC undergoes a phase change. The cross-sectional shape shows that Ti₂The AlC coating has uniform thickness, moderate porosity and Ti inside₂AlC ply, unmelted Ti₂The AlC particles and the impurity phase are combined with the YSZ coating tightly without obvious lamination crack.

The fourth step of subjecting Ti₂The AlC ceramic layer is pre-oxidized in situ to generate an oxide layer.

Ti prepared by supersonic flame spraying in air atmosphere₂The AlC coating is subjected to pre-oxidation heat treatment, and the main process parameters are as follows: the temperature is 1200 ℃, and the temperature is kept for 5 h. The oxidized layer has an inner continuous Al layer₂O₃Outside, inLayer of discontinuous TiO₂The thickness of the double-layer structure of (2) is 1 μm.

Preparation to obtain Ti₂And the AlC/YSZ double-ceramic layer thermal barrier coating.

Coating CMAS powder on the Ti prepared above₂AlC/YSZ thermal barrier coating, and heat treating at 1250 deg.C for 4 h. After CMAS action, Ti₂A compact crystallization layer with anorthite as the main component is formed on the surface of the AlC/YSZ thermal barrier coating, and the compact crystallization layer can effectively prevent the penetration of molten CMAS, which shows that the Ti prepared by the invention₂The AlC/YSZ thermal barrier coating has excellent CMAS corrosion resistance.

Example 3: preparing a thermal barrier coating resisting the corrosion of molten CMAS, wherein the coating consists of a high-temperature alloy substrate, a NiCrAlY bonding layer, a YSZ ceramic layer and Ti₃AlC₂A ceramic layer and a pre-oxide layer thereof, wherein Ti₃AlC₂The coating is prepared by a supersonic flame spraying method, and comprises the following steps:

Second, preparing Ti for supersonic flame spraying₃AlC₂And (3) powder.

To supply Ti₃AlC₂The powder was sieved through a 400 mesh sieve, and the mean particle size of the sieved powder was 38 μm as determined by a particle size analyzer. For increasing Ti content in the coating prepared₃AlC₂Content of (b) by ball milling normal method of Ti₃AlC₂Adding Al powder into the powder, wherein the content of the Al powder is Ti₃AlC₂10% by mass of the powder, Al may be present in one aspect together with Ti₃AlC₂The TiC decomposed in the spraying process reacts to regenerate Ti₃AlC₂On the other hand, Al oxidizes to Al when heated₂O₃Can protect Ti₃AlC₂No phase change occurs.And drying the mixed powder slurry at 120 ℃ for 10 hours for later use.

Thirdly, preparing Ti on the surface of the YSZ ceramic layer by adopting a supersonic flame spraying method₃AlC₂A ceramic layer.

The supersonic flame spraying fuel gas adopts H₂And O₂The spray gun is cooled by compressed air in the spraying process of the mixed gas. Before spraying, the substrate with YSZ coating is preheated, and the preheating temperature is 200 ℃. The main technological parameters adopted in the spraying process are as follows: h₂:O₂The gas flow rate is 45slpm, the powder feeding rate is 15g/min, and the spraying distance is 250 mm. Ti prepared by adopting the parameters₃AlC₂The coating thickness was 10 μm. XRD analysis of the resulting coating showed Ti₃AlC₂The phases being predominant, in addition to which Ti is present₂AlC, TiC and Al_xTi_yEqual impurity phase due to thermal activation of Ti during spraying₃AlC₂Diffusion of medium Al to result in Ti₃AlC₂A phase change occurs. The cross-sectional morphology shows that Ti₃AlC₂Uniform coating thickness, moderate porosity and Ti inside₃AlC₂Lamellar, unmelted Ti₃AlC₂The particles and impurity phase are combined with the YSZ coating tightly without obvious lamination crack.

The fourth step is to Ti₃AlC₂The ceramic layer is pre-oxidized in situ to generate an oxide layer.

Ti prepared by supersonic flame spraying in air atmosphere₃AlC₂The coating is subjected to pre-oxidation heat treatment, and the main process parameters are as follows: the temperature is 1200 ℃, and the temperature is kept for 10 h. The oxidized layer has inner continuous Al layer₂O₃Outer discontinuous TiO₂The thickness of the double-layer structure of (2) is 3 μm.

Preparation to obtain Ti₃AlC₂the/YSZ double ceramic layer thermal barrier coating.

Coating CMAS powder on the Ti prepared above₃AlC₂The thermal barrier coating of/YSZ is thermally treated at 1250 ℃ for 4 h. After CMAS action, Ti₃AlC₂The surface of the/YSZ thermal barrier coating forms a main layerThe essential component is a dense crystalline layer of anorthite, which can effectively prevent penetration of molten CMAS, illustrating that Ti prepared by the invention₃AlC₂the/YSZ thermal barrier coating has excellent CMAS corrosion resistance.

Example 4: preparing a thermal barrier coating resisting the corrosion of molten CMAS, wherein the coating consists of a high-temperature alloy substrate, a NiCrAlY bonding layer, a YSZ ceramic layer and Ti₂AlC ceramic layer and pre-oxide layer thereof, wherein Ti₂The AlC coating is prepared by a suspension plasma spraying method and comprises the following steps:

And preparing the YSZ ceramic layer on the surface of the NiCrAlY bonding layer by adopting an atmospheric plasma spraying method. The main process parameters are as follows: spraying voltage of 60V, current of 600A, main gas Ar flow rate of 40slpm, H₂The flow rate is 10slpm, the powder feeding rate is 15g/min, the spraying distance is 100mm, and the thickness of the obtained YSZ ceramic layer is 150 μm.

Second, preparing suspension Ti for plasma spraying₂And (4) AlC suspension.

To supply Ti₂The AlC powder was sieved through a 500 mesh sieve, and the mean particle size of the sieved powder was 25 μm as determined by a particle size analyzer. For increasing Ti content in the coating produced₂The content of AlC is Ti₂Al powder is added into the AlC powder, and the content is Ti₂20% of the AlC powder by mass, in one aspect Al can be present with Ti₂TiC decomposed from AlC in the spraying process reacts to regenerate Ti₂AlC, on the other hand Al oxidizes to Al when heated₂O₃Can protect Ti₂The AlC does not change phase. Weighing Ti₂30g of AlC powder, 6g of Al powder is weighed, the AlC powder and the Al powder are uniformly mixed by adopting a ball milling method, and zirconia balls and ethanol are selected as ball milling media. The above mixed powder was dissolved in 300ml of deionized water. To improve the uniformity of the dispersion of the suspension particles, 0.3g of PBTCA (2-phospho-1, 2, 4-tricarboxylic acid butane) dispersant was added thereto and stirred by magnetic force to obtain Ti₂And (4) AlC suspension.

Thirdly, preparing Ti on the surface of the YSZ ceramic layer by adopting a suspension plasma spraying method₂AlC potteryAnd (4) a ceramic layer.

Before spraying, the substrate with the YSZ coating was preheated to 300 ℃ using a plasma spray gun. During spraying, the suspension is continuously conveyed to the nozzle by the pressure pump, and the adopted main process parameters are as follows: the spraying current is 500A, the power is 20KW, the spraying distance is 80mm, the Ar flow rate is 20slm, the He flow rate is 20slm, and the suspension flow rate is 10 g/min. Ti prepared by adopting the parameters₂The AlC coating thickness was 10 μm. XRD analysis of the resulting coating showed that Ti₂AlC phase being predominant, and, in addition, Ti₂The unavoidable phase change of AlC during thermal spraying results in a small amount of Ti still being present in the coating₃AlC₂TiC and Al_xTi_yAnd the like. The cross-sectional morphology shows that Ti₂The AlC coating has uniform thickness and moderate porosity, is typical of columnar crystals, and has obvious gaps among the columnar crystals.

The fourth step is to Ti₂The AlC ceramic layer is pre-oxidized in situ to generate an oxide layer.

Ti prepared by plasma spraying of a suspension in an air atmosphere₂The AlC coating is subjected to pre-oxidation heat treatment, and the main process parameters are as follows: the temperature is 1200 ℃, and the temperature is kept for 5 h. The oxidized layer has an inner continuous Al layer₂O₃Outer discontinuous TiO₂The thickness of the double-layer structure of (2) is 1 μm.

Preparation to obtain Ti₂And the AlC/YSZ double-ceramic-layer thermal barrier coating.

Coating CMAS powder on the Ti prepared above₂AlC/YSZ thermal barrier coating, and heat treating at 1250 deg.C for 4 h. After CMAS action, Ti₂A dense crystalline layer with anorthite as a main component is formed on the surface of the AlC/YSZ thermal barrier coating, and the dense crystalline layer can effectively prevent the penetration of molten CMAS, so that the Ti prepared by the method is shown₂The AlC/YSZ thermal barrier coating has excellent CMAS corrosion resistance.

Example 5: preparing a thermal barrier coating resisting the corrosion of molten CMAS, wherein the coating consists of a high-temperature alloy substrate, a NiCrAlY bonding layer, a YSZ ceramic layer and Ti₂AlC ceramic layer and pre-oxidation layer thereof, wherein Ti₂The AlC coating is prepared by a suspension plasma spraying method, comprising the following steps:

Second, preparing suspension Ti for plasma spraying₂And (4) suspending AlC.

To supply Ti₂The AlC powder was sieved through a 500 mesh sieve, and the mean particle size of the sieved powder was 25 μm as determined by a particle size analyzer. For increasing Ti content in the coating produced₂The content of AlC is Ti₂Al powder is added into the AlC powder, and the content is Ti₂20% of the AlC powder by mass, in one aspect Al can be present with Ti₂TiC decomposed from AlC in the spraying process reacts to regenerate Ti₂AlC, on the other hand Al oxidizes to Al when heated₂O₃Can protect Ti₂The AlC does not undergo a phase change. Weighing Ti₂30g of AlC powder, 6g of Al powder is weighed, the AlC powder and the Al powder are uniformly mixed by adopting a ball milling method, and zirconia balls and ethanol are selected as ball milling media. The above mixed powder was dissolved in 300ml of deionized water. To improve the uniformity of the dispersion of the suspension particles, 0.3g of PBTCA (2-phospho-1, 2, 4-tricarboxylic acid butane) dispersant was added thereto and stirred by magnetic force to obtain Ti₂And (4) AlC suspension.

Thirdly, preparing Ti on the surface of the YSZ ceramic layer by adopting a suspension plasma spraying method₂And an AlC ceramic layer.

Before spraying, the substrate with the YSZ coating was preheated to 300 ℃ using a plasma spray gun. During spraying, the suspension is continuously conveyed to the nozzle by the pressure pump, and the adopted main process parameters are as follows: the spraying current is 400A, the power is 30KW, the spraying distance is 80mm, the Ar flow is 25slm, the He flow is 25slm, and the suspension flow is 15 g/min. Ti prepared by adopting the parameters₂The AlC coating thickness was 13 μm. XRD analysis of the resulting coating showed Ti₂AlC phase accounts for the most part, and in addition, Ti₂AlC in the process of thermal sprayingThe inevitable phase transformation results in a small amount of Ti remaining in the coating₃AlC₂TiC and Al_xTi_yAnd the like. The cross-sectional morphology shows that Ti₂The AlC coating is uniform in thickness and moderate in porosity, and is typical in columnar crystal morphology, and obvious gaps exist among columnar crystals.

The fourth step is to Ti₂And pre-oxidizing the AlC ceramic layer to generate an oxide layer in situ.

Ti prepared by plasma spraying of a suspension in an air atmosphere₂The AlC coating is subjected to pre-oxidation heat treatment, and the main process parameters are as follows: the temperature is 1200 ℃, and the temperature is kept for 6 h. The oxidized layer has an inner continuous Al layer₂O₃Outer discontinuous TiO₂The thickness of the double-layer structure of (2) is 2 μm.

Example 6: preparing a thermal barrier coating resisting the corrosion of molten CMAS, wherein the coating consists of a high-temperature alloy substrate, a NiCrAlY bonding layer, a YSZ ceramic layer and Ti₃AlC₂A ceramic layer and a pre-oxide layer thereof, wherein Ti₃AlC₂The coating is prepared by a suspension plasma spraying method, comprising the following steps:

And preparing the YSZ ceramic layer on the surface of the NiCrAlY bonding layer by adopting an atmospheric plasma spraying method. The main process parameters are as follows: spraying voltage of 60V, current of 600A, main gas Ar flow of 40slpm, H₂The flow rate is 10slpm, the powder feeding rate is 15g/min, the spraying distance is 100mm, and the thickness of the obtained YSZ ceramic layer is 150 mu m.

Second, preparing suspension Ti for plasma spraying₃AlC₂And (3) suspension.

To supply Ti₃AlC₂The powder was sieved through a 500 mesh sieve, and the average particle size of the sieved powder was 25 μm as determined by a particle size analyzer. For increasing Ti content in the coating prepared₃AlC₂In the amount of Ti₃AlC₂Adding Al powder into the powder, wherein the content of the Al powder is Ti₃AlC₂20% of the powder mass, Al on the one hand and Ti on the other hand₃AlC₂The TiC decomposed in the spraying process reacts to regenerate Ti₃AlC₂On the other hand, Al oxidizes to Al when heated₂O₃Can protect Ti₃AlC₂No phase change occurs. Weighing Ti₃AlC₂30g of powder, 6g of Al powder is weighed, the powder and the Al powder are uniformly mixed by adopting a ball milling method, and zirconia balls and ethanol are selected as ball milling media. The above mixed powder was dissolved in 300ml of deionized water. To improve the uniformity of the dispersion of the suspension particles, 0.3g of PBTCA (2-phospho-1, 2, 4-tricarboxylic acid butane) dispersant was added thereto and stirred by magnetic force to obtain Ti₃AlC₂And (3) suspension.

Thirdly, preparing Ti on the surface of the YSZ ceramic layer by adopting a suspension plasma spraying method₃AlC₂A ceramic layer.

Before spraying, the substrate with the YSZ coating was preheated to 300 ℃ using a plasma spray gun. During spraying, the suspension is continuously conveyed to the nozzle by the pressure pump, and the adopted main process parameters are as follows: the spraying current is 600A, the power is 50KW, the spraying distance is 40mm, the Ar flow is 30slm, the He flow is 30slm, and the suspension flow is 25 g/min. Ti prepared by adopting the parameters₃AlC₂The coating thickness was 20 μm. XRD analysis of the resulting coating showed Ti₃AlC₂The phases being predominant, in addition, Ti₃AlC₂The unavoidable phase changes during the thermal spraying result in small amounts of Ti still being present in the coating₂AlC, TiC and Al_xTi_yAnd the like. The cross-sectional morphology shows that Ti₃AlC₂The coating has uniform thickness and moderate porosity, is typical of columnar crystal morphology, and obvious gaps exist among the columnar crystals.

The fourth step is toTi₃AlC₂The ceramic layer is pre-oxidized to generate an oxide layer in situ.

Ti prepared by plasma spraying of suspension in air atmosphere₃AlC₂The coating is subjected to pre-oxidation heat treatment, and the main process parameters are as follows: the temperature is 1200 ℃, and the heat preservation is carried out for 8 h. The oxidized layer has an inner continuous Al layer₂O₃Outer discontinuous TiO₂The thickness of the double-layer structure of (2) is 3 μm.

Preparation of Ti₃AlC₂A thermal barrier coating of/YSZ double ceramic layers.

Coating CMAS powder on the Ti prepared above₃AlC₂The thermal barrier coating of/YSZ is thermally treated at 1250 ℃ for 4 h. After CMAS action, Ti₃AlC₂A compact crystallization layer with anorthite as the main component is formed on the surface of the YSZ thermal barrier coating, and the layer can effectively prevent the penetration of molten CMAS, which shows that the Ti prepared by the invention₃AlC₂the/YSZ thermal barrier coating has excellent CMAS corrosion resistance.

Example 7: preparing a thermal barrier coating resisting the corrosion of molten CMAS, wherein the coating consists of a high-temperature alloy substrate, a NiCrAlY bonding layer, a YSZ ceramic layer and Ti₂AlC ceramic layer and pre-oxidation layer thereof, wherein Ti₂The AlC coating is prepared by a plasma spraying-physical vapor deposition method and comprises the following steps:

And preparing the YSZ ceramic layer on the surface of the NiCrAlY bonding layer by adopting an air plasma spraying method. The main process parameters are as follows: spraying voltage of 60V, current of 600A, main gas Ar flow of 40slpm, H₂The flow rate is 10slpm, the powder feeding rate is 15g/min, the spraying distance is 100mm, and the thickness of the obtained YSZ ceramic layer is 150 μm.

Second, preparing Ti for plasma spraying-physical vapor deposition₂AlC powder.

To supply Ti₂The AlC powder was sieved through a 200 mesh sieve, and the mean particle size of the sieved powder was 75 μm as determined by a particle size analyzer. For increasing Ti content in the coating prepared₂The content of AlC adopts a ball milling normal method to Ti₂Al powder is added into AlC powder, and the content is Ti₂15% of the AlC powder by mass, Al may be present in combination with Ti₂TiC decomposed from AlC in the spraying process reacts to regenerate Ti₂AlC, on the other hand Al oxidizes to Al when heated₂O₃Can protect Ti₂The AlC does not undergo a phase change. And drying the mixed powder slurry at 120 ℃ for 10 hours for later use.

Thirdly, preparing Ti on the surface of the YSZ ceramic layer by adopting a plasma spraying-physical vapor deposition method₂And an AlC ceramic layer.

The substrate with the YSZ coating was preheated prior to spraying. The temperature of the substrate before and during spraying was measured with an infrared temperature detector, the average of which was 950 ℃. The main technological parameters adopted by the spraying are as follows: the spraying power is 35KW, the current is 1200A, the pressure of a vacuum chamber is lower than 1mbar, the flow rate of Ar is 30slpm, the flow rate of He is 70slpm, and the spraying distance is 1500 mm. Ti prepared by adopting the parameters₂The AlC coating thickness was 12 μm. XRD analysis of the resulting coating showed Ti₂AlC phase accounts for the most part, and in addition, Ti₂The unavoidable phase change of AlC during thermal spraying results in a small amount of Ti still being present in the coating₃AlC₂TiC and Al_xTi_yAnd the like. The cross-sectional morphology shows that Ti₂The AlC coating has uniform thickness and moderate porosity, presents a typical columnar crystal-like appearance growing in the direction vertical to the substrate, and has obvious gaps among crystal grains.

Ti prepared by plasma spraying-physical vapor deposition in air atmosphere₂The AlC coating is subjected to pre-oxidation heat treatment, and the main process parameters are as follows: the temperature is 1200 ℃, and the heat preservation is carried out for 8 h. The oxidized layer has an inner continuous Al layer₂O₃Outer discontinuous TiO₂The thickness of the double-layer structure of (2) is 3 μm.

Coating CMAS powder on the Ti prepared above₂And carrying out heat treatment on the AlC/YSZ thermal barrier coating at 1250 ℃ for 4 hours.After CMAS, Ti₂A dense crystalline layer with anorthite as a main component is formed on the surface of the AlC/YSZ thermal barrier coating, and the dense crystalline layer can effectively prevent the penetration of molten CMAS, so that the Ti prepared by the method is shown₂The AlC/YSZ thermal barrier coating has excellent CMAS corrosion resistance.

Example 8: preparing a thermal barrier coating resisting the corrosion of molten CMAS, wherein the coating consists of a high-temperature alloy substrate, a NiCrAlY bonding layer, a YSZ ceramic layer and Ti₂AlC ceramic layer and pre-oxidation layer thereof, wherein Ti₂The AlC coating is prepared by a plasma spraying-physical vapor deposition method and comprises the following steps:

To supply Ti₂The AlC powder was sieved through a 200 mesh sieve, and the mean particle size of the sieved powder was 75 μm as determined by a particle size analyzer. For increasing Ti content in the coating prepared₂The content of AlC adopts a ball milling normal method to Ti₂Al powder is added into AlC powder, and the content is Ti₂20% of the AlC powder by mass, in one aspect Al can be present with Ti₂TiC decomposed from AlC in the spraying process reacts to regenerate Ti₂AlC, on the other hand Al oxidizes to Al when heated₂O₃Can protect Ti₂The AlC does not undergo a phase change. And drying the mixed powder slurry at 120 ℃ for 10 hours for later use.

The substrate with the YSZ coating was preheated prior to spraying. The temperature of the substrate before and during spraying was measured with an infrared temperature detector, the average of which was 950 ℃.The main technological parameters adopted by the spraying are as follows: the spraying power is 60KW, the current is 1800A, the pressure of a vacuum chamber is lower than 1mbar, the Ar gas flow is 40slpm, the He gas flow is 60slpm, and the spraying distance is 1200 mm. Ti prepared by adopting the parameters₂The AlC coating thickness was 19 μm. XRD analysis of the resulting coating showed Ti₂AlC phase being predominant, and, in addition, Ti₂The unavoidable phase change of AlC during thermal spraying results in a small amount of Ti still being present in the coating₃AlC₂TiC and Al_xTi_yAnd the like. The cross-sectional morphology shows that Ti₂The AlC coating has uniform thickness and moderate porosity, presents a typical columnar crystal-like appearance growing in the direction vertical to the substrate, and has obvious gaps among crystal grains.

Ti prepared by plasma spraying-physical vapor deposition in air atmosphere₂The AlC coating is subjected to pre-oxidation heat treatment, and the main process parameters are as follows: the temperature is 1200 ℃, and the heat preservation is carried out for 6 h. The oxidized layer has an inner continuous Al layer₂O₃Outer discontinuous TiO₂The thickness of the double-layer structure of (2) is 2 μm.

Example 9: preparing a thermal barrier coating resisting the corrosion of molten CMAS, wherein the coating consists of a high-temperature alloy substrate, a NiCrAlY bonding layer, a YSZ ceramic layer and Ti₃AlC₂A ceramic layer and a pre-oxide layer thereof, wherein Ti₃AlC₂The coating is prepared by a plasma spraying-physical vapor deposition method, and comprises the following steps:

Second, preparing Ti for plasma spraying-physical vapor deposition₃AlC₂And (3) powder.

To supply Ti₃AlC₂The powder was sieved through a 200 mesh sieve, and the mean particle size of the sieved powder was 75 μm as determined by a particle size analyzer. For increasing Ti content in the coating prepared₃AlC₂Content of (b) by ball milling normal method of Ti₃AlC₂Adding Al powder into the powder, wherein the content of the Al powder is Ti₃AlC₂10% by mass of the powder, Al may be present in one aspect together with Ti₃AlC₂The TiC decomposed in the spraying process reacts to regenerate Ti₃AlC₂On the other hand, Al oxidizes to Al when heated₂O₃Can protect Ti₃AlC₂No phase change occurs. And drying the mixed powder slurry at 120 ℃ for 10 hours for later use.

Thirdly, preparing Ti on the surface of the YSZ ceramic layer by adopting a plasma spraying-physical vapor deposition method₃AlC₂A ceramic layer.

The substrate with the YSZ coating was preheated prior to spraying. The temperature of the substrate before and during spraying was measured with an infrared temperature detector, the average of which was 950 ℃. The main technological parameters adopted by the spraying are as follows: the spraying power is 30KW, the current is 1200A, the pressure of a vacuum chamber is lower than 1mbar, the Ar gas flow is 30slpm, the He gas flow is 40slpm, and the spraying distance is 1800 mm. Ti prepared by adopting the parameters₃AlC₂The coating thickness was 10 μm. XRD analysis of the resulting coating showed Ti₃AlC₂The phases being predominant, in addition, Ti₃AlC₂The unavoidable phase changes during the thermal spraying result in small amounts of Ti still being present in the coating₂AlC, TiC and Al_xTi_yAnd the like. The cross-sectional morphology shows that Ti₃AlC₂The coating has uniform thickness and moderate porosity, presents a typical columnar crystal appearance growing in the direction vertical to the substrate, and obvious gaps exist among the crystal grains.

The fourth step of subjecting Ti₃AlC₂The ceramic layer is pre-oxidized in situ to generate an oxide layer.

Ti prepared by plasma spraying-physical vapor deposition in air atmosphere₃AlC₂The coating is subjected to pre-oxidation heat treatment, and the main process parameters are as follows: the temperature is 1200 ℃, and the temperature is kept for 10 h. The oxidized layer has inner continuous Al layer₂O₃Outer discontinuous TiO₂The thickness of the double-layer structure of (2) is 3 μm.

Coating CMAS powder on the Ti prepared above₃AlC₂The thermal barrier coating/YSZ is subjected to heat treatment at 1250 ℃ for 4 h. After CMAS, Ti₃AlC₂A compact crystallization layer with anorthite as the main component is formed on the surface of the YSZ thermal barrier coating, and the layer can effectively prevent the penetration of molten CMAS, which shows that the Ti prepared by the invention₃AlC₂the/YSZ thermal barrier coating has excellent CMAS corrosion resistance.

Claims

1. A MAX phase coating for a thermal barrier coating resistant to molten CMAS corrosion, characterized by: the MAX phase material comprises Ti₂AlC or Ti₃AlC₂The MAX phase coating is 10-20 mu m in thickness, the porosity is 3-10%, and the MAX phase coating is provided with a pre-oxidation layer, and the preparation method comprises the following steps:

1) preparation of MAX phase Ti for thermal spraying₂AlC or Ti₃AlC₂Powder or suspension with particle size of 10-100 μm, wherein the suspension is water-based or ethanol-based and neutral or acidic;

2) preparing an MAX phase coating on the surface of a YSZ ceramic layer with a high-temperature alloy and a bonding layer by adopting a thermal spraying method;

3) and carrying out heat treatment on the prepared MAX phase coating to form a pre-oxidation layer with the thickness of 1-3 mu m.

2. A method of preparing a MAX phase coating for a thermal barrier coating resistant to corrosion by molten CMAS as claimed in claim 1 comprising the steps of:

2) preparing a MAX phase coating on the surface of the YSZ ceramic layer with the high-temperature alloy and the bonding layer by adopting a thermal spraying method;

3. The production method according to claim 2, characterized in that: in the step 3), the heat treatment system for pre-oxidizing the MAX phase coating is as follows: and (3) keeping the temperature of the air atmosphere at 1200 ℃ for 5-10 h.

4. The method of claim 2, wherein: in the step 1), Al powder is added into the MAX phase powder or the suspension, wherein the content of the added Al powder is 10-20% of the mass of the MAX phase powder.

5. The method of claim 2, wherein: in the step 2), the thermal spraying method comprises supersonic flame spraying, suspension plasma spraying, plasma spraying-physical vapor deposition.

6. The method of claim 5, wherein: the thermal spraying method adopts a supersonic flame spraying method to prepare the MAX phase coating, wherein H is₂:O₂The spraying device has the advantages that the gas flow is 40-50 slpm, the powder feeding rate is 15-25 g/min, the spraying distance is 120-250 mm, and the preheating temperature of a matrix is 200-450 ℃.

7. The method of claim 5, wherein: the MAX phase coating is prepared by adopting a suspension plasma spraying method, wherein the spraying current is 350-600A, the power is 20-50 KW, the spraying distance is 40-80 mm, the Ar flow is 10-40 slpm, the He flow is 8-40 slpm, and the suspension flow is 10-25 g/min.

8. The method of claim 5, wherein: the MAX phase coating is prepared by adopting a plasma spraying-physical vapor deposition method, wherein the spraying power is 30-60 KW, the current is 1200-2000A, the pressure of a vacuum chamber is lower than 1mbar, the flow rate of Ar is 30-50 slpm, the flow rate of He is 40-70 slpm, and the spraying distance is 1200-1800 mm.

9. The use of a molten CMAS corrosion resistant MAX phase coating of claim 1 for surface protection of hot end components of an aircraft engine.