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CN-122013184-A - TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating and preparation method thereof

CN122013184ACN 122013184 ACN122013184 ACN 122013184ACN-122013184-A

Abstract

The invention provides a TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating and a preparation method thereof, wherein the thermal barrier coating for the surface of the TiAl alloy is added with a self-healing layer, so that the high-temperature oxidation resistance of the TiAl alloy is improved on the basis of reducing the porosity of the self-healing thermal barrier coating, and the preparation method of the thermal barrier coating comprises the following specific steps that firstly, niCoCrAlYHf bonding layers are prepared on the surface of a TiAl alloy substrate by adopting vacuum arc plating; secondly, adopting atmospheric plasma to spray an Al 2 O 3 -13wt.%TiO 2 ceramic layer on the surface of the prepared bonding layer to form a thermal barrier layer with a heat insulation effect, thirdly, preparing a self-healing layer based on Ti 3 SiC 2 on the surface of the ceramic layer, and utilizing the self-healing agent of Ti 3 SiC 2 to expand in volume under a high temperature condition to generate a sealing effect in the coating, so that pores and microcracks in the coating are healed finally, and further, the high-temperature oxidation resistance of TiAl alloy is improved.

Inventors

  • HE TAN
  • LIU LING
  • YU WENTAO
  • ZHANG YONGJIAN
  • WU YANG
  • LIU SHAOJUN

Assignees

  • 西安文理学院

Dates

Publication Date
20260512
Application Date
20260202
Priority Date
20251114

Claims (10)

  1. 1. The preparation method of the TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating is characterized by comprising the following steps of: s1, preprocessing a TiAl alloy sample; S2, depositing NiCoCrAlYHf coating on the surface of the TiAl alloy through vacuum arc plating, and then carrying out vacuum heat treatment to obtain a bonding layer, wherein the NiCoCrAlYHf coating comprises 56wt.% of Ni, 13wt.% of Co, 18wt.% of Cr, 12wt.% of Al, 0.4wt.% of Y and 0.6wt.% of Hf; S3, preparing mixed powder sprayed with Al 2 O 3 and TiO 2 on the surface of the bonding layer by atmospheric plasma spraying to obtain a ceramic layer; S4, spraying mixed powder of three powders of Al 2 O 3 、TiO 2 and Ti 3 SiC 2 on the ceramic layer through atmospheric plasma spraying to obtain a surface self-healing layer, wherein the mass ratio of Al 2 O 3 in the mixed powder is 75 wt%, the mass ratio of TiO 2 is 11 wt%, and the mass ratio of Ti 3 SiC 2 is 14 wt%, so that a high-temperature oxidation-resistant self-healing thermal barrier coating is formed; In the service process of the high-temperature oxidation-resistant self-healing thermal barrier coating, ti 3 SiC 2 is oxidized to generate volume proliferation, meanwhile SiO 2 is generated, and the phase is changed into a molten state from crystallization to supplement cracks.
  2. 2. The method for preparing the TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating according to claim 1, wherein in the step S1, the pretreatment process is to remove surface rust and oxide films by mechanical polishing, and then ultrasonic cleaning by acetone and absolute ethyl alcohol, and drying and then placing into a coating vacuum chamber.
  3. 3. The method for preparing the TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating according to claim 1, wherein in the S2, the vacuum degree is 10 -3 Pa, the current is 700A, the voltage is 30V, the deposition time is 2h, and the coating is cooled and subjected to heat treatment after the deposition is finished.
  4. 4. The method for preparing the TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating according to claim 3, wherein the cooling and heat treatment process comprises the steps of taking out a sample after cooling for 1h in a vacuum chamber, then placing the sample in a high-temperature vacuum diffusion furnace for carrying out vacuum heat treatment at 900 ℃ for 5h, and taking out the sample after cooling to below 200 ℃ along with the furnace.
  5. 5. The method for preparing the TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating according to claim 1, wherein in the step S3, parameters of atmospheric plasma spraying are that spraying voltage is 62V, spraying current is 600A, spraying distance is 120 mm, and powder feeding rate is 24g/min.
  6. 6. The method for preparing the TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating according to claim 1, wherein in S4, the spraying voltage in the atmospheric plasma spraying process is 62V, the spraying current is 650A, the spraying distance is 120 mm, and the powder feeding rate is 9.5g/min.
  7. 7. The method for preparing the TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating according to claim 1, wherein in S3, the mass ratio of Al 2 O 3 in the mixed powder of Al 2 O 3 and TiO 2 is 75wt.% and the mass ratio of TiO 2 is 11wt.%.
  8. 8. The method for preparing the TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating according to claim 1, wherein the thickness of the bonding layer is 25-30 microns, the thickness of the ceramic layer is 110-120 microns, and the thickness of the self-healing layer is 10-15 microns.
  9. 9. A high temperature oxidation resistant self-healing thermal barrier coating of TiAl alloy obtained by the method of any one of claims 1 to 8, characterized in that it comprises a bonding layer, a ceramic layer and a self-healing layer arranged on the surface of the TiAl alloy from inside to outside, the bonding layer being NiCoCrAlYHf coating, the ceramic layer being composed of Al 2 O 3 and TiO 2 , the surface self-healing layer being composed of Al 2 O 3 、TiO 2 and Ti 3 SiC 2 .
  10. 10. The TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating obtained by the preparation method of any one of claims 1-9, which is characterized in that the thickness of the bonding layer is 25-30 mu m, the thickness of the ceramic layer is 110-120 mu m, and the thickness of the self-healing layer is 10-15 mu m.

Description

TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating and preparation method thereof Technical Field The invention relates to the technical field of surface treatment, in particular to a TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating and a preparation method thereof. Background The gamma-TiAl alloy has excellent high-temperature strength, corrosion resistance and creep resistance, is an ideal material for 650-1000 ℃ engine parts, but has poor room-temperature plasticity and low hardness, and the oxidation resistance is obviously reduced above 750 ℃. The surface coating technology is an important means for improving the oxidation resistance of the alloy, and noble metals (such as Au and Pt) and Thermal Barrier Coatings (TBCs) with multilayer and gradient structures are widely used. However, the existing coating has a problem of porosity higher than 5%, resulting in penetration of an oxidizing atmosphere into the bonding layer, forming Thermally Grown Oxide (TGO). TGO overgrowth can cause stress due to thermal expansion coefficient mismatch, resulting in transverse cracking and ceramic layer spalling, which is the primary cause of TBCs failure. Cracks and pores are typical defects of TBCs, pores affect thermal conductivity, and crack propagation directly determines coating life. The introduction of self-healing agents (e.g., siC, tiC, moSi 2, etc.) can inhibit TGO growth by filling cracks with oxidation products. However, siO 2 generated by SiC is easy to react and volatilize with water vapor, the filling effect is limited after TiC is oxidized, al 2O3 is often required to be added to enhance the oxygen resistance, and MoSi 2 materials have the problem of low-temperature pulverization and influence the bonding performance. Therefore, developing a highly effective and stable self-healing coating remains a key challenge. Disclosure of Invention The invention aims to overcome the defects of the prior art, and provides a TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating and a preparation method thereof, so as to solve the problems that various self-healing agents introduced in the prior art are easy to volatilize, have limited filling effect or have low-temperature pulverization in the application process. In order to achieve the purpose, the invention is realized by adopting the following technical scheme: a preparation method of a TiAl alloy high-temperature oxidation-resistant self-healing thermal barrier coating comprises the following steps: s1, preprocessing a TiAl alloy sample; S2, depositing NiCoCrAlYHf coating on the surface of the TiAl alloy through vacuum arc plating, and then carrying out vacuum heat treatment to obtain a bonding layer, wherein the NiCoCrAlYHf coating comprises 56wt.% of Ni, 13wt.% of Co, 18wt.% of Cr, 12wt.% of Al, 0.4wt.% of Y and 0.6wt.% of Hf; S3, preparing mixed powder sprayed with Al 2O3 and TiO 2 on the surface of the bonding layer by atmospheric plasma spraying to obtain a ceramic layer; S4, spraying mixed powder of three powders of Al 2O3、TiO2 and Ti 3SiC2 on the ceramic layer through atmospheric plasma spraying to obtain a surface self-healing layer, wherein the mass ratio of Al 2O3 in the mixed powder is 75 wt%, the mass ratio of TiO 2 is 11 wt%, and the mass ratio of Ti 3SiC2 is 14 wt%, so that a high-temperature oxidation-resistant self-healing thermal barrier coating is formed; In the service process of the high-temperature oxidation-resistant self-healing thermal barrier coating, ti 3SiC2 is oxidized to generate volume proliferation, meanwhile SiO 2 is generated, and the phase is changed into a molten state from crystallization to supplement cracks. The invention further improves that: preferably, in S1, the pretreatment process is to remove surface rust and oxide film by mechanical polishing, then ultrasonically clean with acetone and absolute ethyl alcohol, and dry and then put into a coating vacuum chamber. Preferably, in the step S2, in the treatment process of the vacuum arc plating, the vacuum degree is 10 -3 Pa, the current is 700A, the voltage is 30V, the deposition time is 2 hours, and the cooling and the heat treatment are carried out after the deposition is finished. Preferably, the cooling and heat treatment process is that the sample is taken out after the vacuum chamber is cooled for 1h, then the sample is placed in a high-temperature vacuum diffusion furnace for 5h of vacuum heat treatment at 900 ℃, and the sample is taken out after the sample is cooled to below 200 ℃ along with the furnace. Preferably, in S3, the parameters of the atmospheric plasma spraying are that the spraying voltage is 62V, the spraying current is 600A, the spraying distance is 120 mm, and the powder feeding rate is 24g/min. Preferably, in S4, the spraying voltage in the atmospheric plasma spraying process is 62V, the spraying current is 650A, the spraying distance is 120 mm, and