CN-121992352-A - Ceramic-based diffusion barrier platinum-aluminum coating formed in situ, and preparation method and application thereof

Abstract

The invention discloses an in-situ formed ceramic-based diffusion barrier platinum-aluminum coating and a preparation method and application thereof, and belongs to the technical field of platinum-aluminum coating series diffusion coatings. The coating comprises an outer platinum aluminum coating, an in-situ generated HfO 2 /Al 2 O 3 ceramic-based diffusion barrier region and an inter-diffusion layer from outside to inside in sequence, and the preparation method comprises the steps of sequentially introducing a Ni-HfO 2 -Hf layer or a Ni-HfO 2 layer, a Pt layer or a Pt-Hf layer on a substrate, and then sequentially carrying out vacuum diffusion annealing treatment and gas phase aluminizing treatment. The in-situ generated HfO 2 /Al 2 O 3 ceramic-based diffusion barrier platinum-aluminum coating provided by the invention is excellent in the aspect of preventing element interdiffusion, and meanwhile, has excellent service reliability. The coating is applied to hot end components of aeroengines and aerospace engines, can obviously prolong the service life of the hot end components, and has important significance in guaranteeing long-term stable operation of the aeroengines and improving the overall performance of equipment.

Inventors

• YANG YINGFEI
• LU YUNJIE
• REN PAN
• WANG QIWEI

Assignees

• 暨南大学

Dates

Publication Date

20260508

Application Date

20260122

Claims (9)

1. 1. The in-situ formed ceramic-based diffusion barrier platinum-aluminum coating is characterized by sequentially comprising an outer platinum-aluminum coating, an in-situ generated HfO 2 /Al 2 O 3 ceramic-based diffusion barrier region and an inter-diffusion layer from outside to inside.
2. 2. The in-situ formed ceramic-based diffusion barrier platinum-aluminum coating of claim 1, wherein the coating composition is graded from outside to inside, and the phase structure gradually transitions from a high aluminum phase to a medium aluminum phase to a low aluminum phase from outside to inside.
3. 3. A method for preparing the in-situ formed ceramic-based diffusion barrier platinum-aluminum coating according to claim 1 or 2, which is characterized by comprising the steps of introducing a Ni-HfO 2 -Hf layer or a Ni-HfO 2 layer on a substrate, then introducing a Pt layer or a Pt-Hf layer on the Ni-HfO 2 -Hf layer or the Ni-HfO 2 layer, and then sequentially carrying out vacuum diffusion annealing treatment and gas phase aluminizing treatment on the obtained composite coating to obtain the in-situ formed ceramic-based diffusion barrier platinum-aluminum coating.
4. 4. The method according to claim 3, wherein the substrate comprises a nickel-based single crystal superalloy, the Ni-HfO 2 -Hf layer, the Ni-HfO 2 layer, the Pt layer and the Pt-Hf layer are introduced by electroplating, sputtering or ion implantation, the thickness of the Ni-HfO 2 -Hf layer or the Hf layer is 12-18 μm, and the thickness of the Pt or Pt-Hf layer is 3-7 μm.
5. 5. The method according to claim 4, wherein the Ni-HfO 2 -Hf layer or Ni-HfO 2 layer, the Pt layer or Pt-Hf layer is formed by electroplating, the specific conditions of the Ni-HfO 2 -Hf layer or Ni-HfO 2 layer are that the electroplating temperature is 40-50 ℃, the current density is 4.8 mA/cm 2 , the pH value is 3-4, the electroplating time is 2h, the specific conditions of the Pt layer or Pt-Hf layer are that the electroplating temperature is 70-80 ℃, the current density is 7 mA/cm 2 , the pH value is 10.0-11.0, and the electroplating time is 1 h.
6. 6. The method according to claim 3, wherein the vacuum degree of the vacuum diffusion annealing treatment is lower than 1 x 10 -3 Pa, the heating rate is 5-10 ℃ per minute, the annealing temperature is 1000-1080 ℃, and the heat preservation time is 1-4 hours.
7. 7. The method according to claim 3, wherein the gas phase aluminizing treatment is performed at 1020-1080 ℃, the heat preservation time is 6h, ar gas is introduced as a protective gas in the aluminizing process, the penetrating agent consists of iron-aluminum mixed powder and an activating agent NH 4 Cl, wherein the NH 4 Cl content is 1-4 wt%, and the iron powder content in the iron-aluminum mixed powder is 49wt%.
8. 8. Use of the in-situ formed ceramic-based diffusion barrier platinum-aluminum coating according to claim 1 or 2 in the aerospace field.
9. 9. The use of claim 8, wherein the in-situ formed ceramic-based diffusion barrier platinum aluminum coating is used in an aerospace engine component protective coating.

Description

Ceramic-based diffusion barrier platinum-aluminum coating formed in situ, and preparation method and application thereof Technical Field The invention belongs to the technical field of platinum-aluminum coating series diffusion coatings, and particularly relates to an in-situ formed ceramic-based diffusion barrier platinum-aluminum coating, and a preparation method and application thereof. Background The beta- (Ni, pt) Al coating is widely applied to key hot end parts of an aeroengine, such as turbine blades and the like, due to the excellent high-temperature oxidation resistance and corrosion resistance, and becomes one of the most mainstream high-temperature protective coatings at present. The Pt element is introduced into the coating, so that the adhesiveness of an alumina film can be obviously enhanced, the overall oxidation resistance is improved, and meanwhile, the Pt can effectively inhibit the high-speed diffusion of Al and Ni in the coating, so that the generation risk of a topological close-packed (TCP) phase is reduced. However, as the thrust-weight ratio of the engine is further increased, the service temperature of the hot-end component is continuously increased, and the phenomenon of interdiffusion between the beta- (Ni, pt) Al coating and the substrate is increasingly serious, so that the phenomenon becomes a key factor for limiting the long-term service life of the hot-end component. Because the composition difference between the coating and the matrix is obvious, the interdiffusion behavior inevitably occurs under the high temperature condition, firstly, al diffuses to the matrix to cause beta-phase gamma '-Ni 3 Al phase transformation, so that the oxidation resistance of the coating is weakened and the appearance degradation of the coating is initiated, secondly, ni diffuses to the outside of the coating to destroy the gamma/gamma' coherent structure of the matrix to generate a Secondary Reaction Zone (SRZ), and the mechanical property of the matrix is seriously damaged. To suppress interdiffusion, metal-based or ceramic-based diffusion barrier layers (DB) are mainly used in current research. The ceramic-based DB (such as Al 2O3, alN and YSZ) has good diffusion resistance effect and structural stability, but the preparation of the beta- (Ni, pt) Al diffusion coating needs to depend on outward diffusion of matrix elements and react with a penetrating agent to maintain growth, and the pre-applied ceramic-based diffusion barrier can prevent the growth of the beta- (Ni, pt) Al coating and is not suitable for a diffusion type aluminizing process. The metal-based DB (such as Ni-Re, ni-W, hf and other systems) can be generated in situ in the coating preparation process, has good toughness and thermal stability, can relieve interface stress, but has the common degradation problems of element out-diffusion and gradual disappearance of a layer structure at a high temperature for a long time, and has the barrier property and stability which are still difficult to meet the strict service requirements. Disclosure of Invention In order to solve the problems in the prior art, the invention provides an in-situ formed ceramic-based diffusion barrier platinum-aluminum coating, and a preparation method and application thereof. In order to achieve the above purpose, the present invention provides the following technical solutions: The invention provides an in-situ formed ceramic-based diffusion barrier platinum-aluminum coating, which sequentially comprises an outer platinum-aluminum coating, an in-situ generated HfO 2/Al2O3 ceramic-based diffusion barrier region and an inter-diffusion layer (IDZ) from outside to inside. As a preferable scheme of the invention, the coating composition is distributed in a gradient way from outside to inside, and the phase structure gradually transits from the high aluminum phase to the medium aluminum phase to the low aluminum phase from outside to inside. The invention also provides a preparation method of the ceramic-based diffusion barrier platinum-aluminum coating formed in situ, which comprises the following steps of introducing a Ni-HfO 2 -Hf layer or a Ni-HfO 2 layer on a substrate, then introducing a Pt layer or a Pt-Hf layer on the Ni-HfO 2 -Hf layer or the Ni-HfO 2 layer, and then sequentially carrying out vacuum diffusion annealing treatment and gas phase aluminizing treatment on the obtained composite coating to obtain the ceramic-based diffusion barrier platinum-aluminum coating formed in situ. The Ni-HfO 2 -Hf or Ni-HfO 2 composite coating provides a Ni source required by coating growth in the aluminizing process, the Pt or Pt-Hf layer provides a Pt source, meanwhile, hf element is outwards diffused into the platinum-aluminum coating, hf modification of the (Ni, pt) Al coating is achieved, and HfO 2 phase is generated in situ in a diffusion barrier region. The HfO 2/Al2O3 ceramic-based diffusion barrier can obviously reduce the oxidation rate of the coating in a