CN112126889A - Method for optimizing thermal barrier coating stability by constructing bionic structure through 3D printing - Google Patents

Abstract

The invention discloses a method for optimizing thermal barrier coating stability by constructing a bionic structure through 3D printing. The method comprises the following steps: s1: the high-temperature alloy matrix is subjected to acetone solution immersion cleaning, ultrasonic cleaning and sand blasting pretreatment; s2: constructing a tree root imitating structure on a high-temperature alloy matrix layer by adopting a coaxial powder feeding laser 3D printing technology; s3: and depositing a YSZ ceramic layer on the tree root structure-imitated interface and the high-temperature alloy substrate layer by a plasma spraying method. According to the invention, a multi-stage forked root-imitated structure is constructed by a 3D printing technology, so that the contact area between the ceramic layer and the high-temperature alloy matrix layer can be increased, and the 'locking effect' of the ceramic layer is realized by the enlarged forked end. Meanwhile, the three-dimensional forked tree root-like structure can effectively prevent the combination of the cracks of the interface and the near interface or promote the deflection of the cracks of the interface and the near interface, and the bonding strength of the interface is increased. Thus, thermal barrier coatings may achieve enhanced interfacial stability and lifetime.

Description

A method for 3D printing to build biomimetic structures to optimize the stability of thermal barrier coatings

technical field

The invention relates to the technical field of thermal barrier coatings, in particular to a method for 3D printing to construct a bionic structure to optimize the stability of thermal barrier coatings.

Background technique

The application of high-efficiency thermal barrier coatings is the most practical way to further increase the operating limits of aero-engines or gas turbines. Currently widely used thermal barrier coatings are mainly composed of low thermal conductivity yttrium stabilized zirconia (YSZ), thermally grown oxide layers and metal bonding layers. The thermal barrier coating can isolate the metal substrate from the hot air flow through the ceramic layer with low thermal conductivity, so that the high-temperature components of the aero-engine or gas turbine such as blades and combustion chambers can serve stably at higher gas temperatures, thereby improving the engine's performance. Work efficiency and service life. However, during high temperature service, the thermal barrier coating is prone to crack initiation, propagation and coalescence at the interface between the ceramic layer and the bonding layer or in the ceramic layer near the interface, which eventually leads to the spalling failure of the thermal barrier coating. This will directly expose the metal matrix to high-temperature gas, causing serious consequences such as engine failure. Therefore, improving the interface and near-interface stability of thermal barrier coatings is the core problem that needs to be solved urgently to prolong its service life, and it is also one of the key problems that needs to be solved urgently for the development of aero-engines and ground gas turbines.

In order to improve the interface stability of the atmospheric plasma spraying thermal barrier coating system, the commonly used methods are: (1) Sandblasting the surface of the bonding layer to increase the surface roughness of the bonding layer to promote the bonding with the ceramic layer. Mechanical bite. However, the rough interface will lead to the radial tensile stress of the interface and the generation of brittle spinel phase, which is not conducive to the stability of the interface. So far, the optimized interface roughness values are still not uniform. (2) Add active elements such as Hf, Ti or Zr to the bonding layer to promote the "capture" of harmful element sulfur and inhibit its diffusion to the interface, thereby improving the interface bonding strength. (3) Optimize the microstructure of the bonding layer, promote the formation of a dense alumina layer, and achieve the purpose of interface enhancement. In general, the current methods have limited enhancement effect on the interface between the ceramic layer and the bonding layer, and none of them can inhibit the cracking and peeling of the ceramic layer near the interface.

SUMMARY OF THE INVENTION

The purpose of the present invention is to propose a method for 3D printing to construct a biomimetic structure to optimize the stability of a thermal barrier coating in view of the above-mentioned deficiencies of the prior art.

The concrete technical scheme of the present invention is as follows:

A method for 3D printing and constructing a bionic structure to optimize the stability of a thermal barrier coating of the present invention includes the following steps:

S1: Pretreatment by acetone solution immersion, ultrasonic cleaning and sandblasting on the superalloy substrate;

S2: Using coaxial powder feeding laser 3D printing technology to build a tree root-like structure on the superalloy base layer;

S3: A YSZ ceramic layer is deposited on the interface of the imitation tree root structure and the superalloy base layer by the plasma spraying method.

Preferably, the imitation tree root structure in step S2 is a multi-level bifurcation imitation tree root structure, the distance S of each bifurcation imitation tree root structure is 1-20 mm, the height H is 50-500 μm, and the bifurcation angle is 50-500 μm. θ is 10-90°, fractal length L ₁ is 50-500 μm, thickness T is 100-500 μm, length L ₂ is 50-500 μm, and the number of bifurcation stages is 1-3.

Preferably, the material of the tree root-like structure is NiCoCrAlY or NiCrAlY.

Preferably, for the fiber laser used in the 3D printing technology in step S2, the rated laser power is 500-1000W, the diameter of the laser beam spot is 50-200μm, the laser power is 80-120W, the powder feeding amount is 2-8g/min, and the scanning The rate is 5-15mm/s, the molten pool is protected with argon gas, and the flow rate is 3-6L/min.

A method for 3D printing to construct a biomimetic structure to optimize the stability of a thermal barrier coating, comprising the following steps:

S1: Pretreatment by acetone solution immersion, ultrasonic cleaning and sandblasting on the superalloy substrate;

S2: deposit an adhesive layer on the pretreated metal substrate surface by plasma spraying or supersonic flame spraying;

S3: Using coaxial powder feeding laser 3D printing technology to build a tree root-like structure at the interface of the bonding layer;

S4: A YSZ ceramic layer is deposited on the interface between the bonding layer and the tree root-like structure by plasma spraying.

Preferably, the material of the adhesive layer is NiCoCrAlY or NiCrAlY; the imitation tree root structure is the same as the material of the adhesive layer.

Preferably, the superalloy matrix is one of an iron-based superalloy matrix, a nickel-based superalloy matrix or a cobalt-based superalloy matrix. The specific models of the iron-based superalloy substrate may be GH1015, GH2018, etc., and the specific models of the nickel-based superalloy substrate may be GH3030, GH4033, and the like.

Preferably, the thickness of the adhesive layer is 80-200 μm.

Preferably, the imitation tree root structure in step S2 is a multi-level bifurcation imitation tree root structure, the distance S of each bifurcation imitation tree root structure is 1-20 mm, the height H is 50-500 μm, and the bifurcation angle is 50-500 μm. θ is 10-90°, fractal length L ₁ is 50-500 μm, thickness T is 100-500 μm, length L ₂ is 50-500 μm, and the number of bifurcation stages is 1-3.

Preferably, for the fiber laser used in the 3D printing technology in step S2, the rated laser power is 500-1000W, the diameter of the laser beam spot is 50-200μm, the laser power is 80-120W, the powder feeding amount is 2-8g/min, and the scanning The rate is 5-15mm/s, the molten pool is protected with argon gas, and the flow rate is 3-6L/min.

In the present invention, a multi-level bifurcated tree root structure is constructed at the interface of the ceramic layer and the adhesive layer of the thermal barrier coating through the 3D printing technology. The head achieves a "lock" effect on the ceramic layer, while compression with the metal layer can transmit stress. The stress transfer is not sensitive to the interface state, and it can effectively improve the interface stability and life even if the interface state is not good.

The invention constructs a multi-level bifurcated tree root-like structure through the 3D printing technology, which can increase the contact area between the ceramic layer and the superalloy base layer and increase the mechanical occlusion strength. At the same time, the three-dimensional bifurcated tree root-like structure can effectively prevent the merging of interface and near-interface cracks or promote the deflection of interface and near-interface cracks, thereby increasing the interface bonding strength. Thus, the thermal barrier coating can achieve enhanced interfacial stability and lifetime.

Description of drawings

1 is a schematic diagram of the cross-sectional effect of the thermal barrier coating of Example 1;

2 is a schematic diagram of the cross-sectional effect of the thermal barrier coating of Example 2;

3 is a schematic diagram of the cross-sectional effect of the thermal barrier coating of Example 3;

In the figure: 1-imitation tree root structure; 2-ceramic layer; 3-superalloy base layer; 4-bonding layer.

Detailed ways

The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

Example 1

First, the superalloy base layer 3 is ultrasonically cleaned, degreasing and sandblasted. Then, a NiCoCrAlY bonding layer 4 is deposited on the superalloy base layer 3 by a supersonic flame spraying method, and its thickness is 100 μm. The parameters of the first-level bifurcation-like tree root structure 1 are set according to the program, and the first-level bifurcated tree-like root structure 1 is constructed on the surface of the adhesive layer 4 by using the coaxial powder feeding laser 3D printing technology. The superalloy matrix is Hastelloy superalloy matrix.

As shown in Fig. 1, the spacing S of each imitation tree root structure 1 is 5 mm, the height H is 100 μm, the bifurcation angle θ is 45°, the fractal length L1 is ₁₀₀ μm, the thickness T is 100 μm, the length L2 is 50 μm, and the composition Same as adhesive layer 4. In the process of coaxial powder feeding laser 3D printing, the rated power of the laser is 500W, the diameter of the laser beam spot is 70μm, the laser power is 80W, the powder feeding method is coaxial powder feeding, the powder feeding amount is 2g/min, and the scanning rate is 7mm/ s, the argon flow rate is 5L/min. Finally, the YSZ ceramic layer 2 is deposited on the interface between the bonding layer 4 and the imitation tree root structure 1 by the atmospheric plasma spraying method, and the thickness of the layer is 200 μm.

The results of high temperature thermal cycling experiments at 1150 °C show that when the peeling area of the ceramic layer 2 of the traditional thermal barrier coating exceeds 30%, the surface of the thermal barrier coating with a tree root-like structure 1 at the interface has no peeling, showing excellent high temperature thermal cycling stability. sex. It shows that the interfacial tree root-like structure 1 can effectively improve the life and reliability of thermal barrier coatings. The 3D printing method for constructing a biomimetic structure to optimize the interface stability can also be extended to other related fields, and has good application value.

Example 2: The implementation steps of this implementation manner that are different from the specific example 1 are that the imitation tree root structure 1 is a secondary fork. Others are the same as the specific embodiment 1.

The superalloy base layer 3 is cleaned and degreasing, and the surface is sandblasted with alumina particles, and then a NiCoCrAlY bonding layer 4 with a thickness of 100 μm is deposited on the alloy base by supersonic flame spraying. According to the program setting, a secondary bifurcated tree root-like structure 1 is constructed on the surface of the adhesive layer 4 by coaxial powder feeding laser 3D printing technology.

As shown in Figure 2, the specific parameters are: the spacing S of each imitation tree root structure ₁ is 5mm, the height H is 100μm, the bifurcation angle θ is 45°, the fractal length L1 is 100μm, the thickness T is 100μm, and the length L ₂ is 50 μm, and the composition is the same as that of the adhesive layer 4 . In the process of coaxial powder feeding laser 3D printing, the rated power of the laser is 500W, the diameter of the laser beam spot is 70μm, the laser power is 80W, the powder feeding method is coaxial powder feeding, the powder feeding amount is 2g/min, and the scanning rate is 7mm/ s, the argon flow rate is 5L/min. Finally, the YSZ ceramic layer 2 is deposited on the interface between the bonding layer 4 and the imitation tree root structure 1 by the atmospheric plasma spraying method, and the thickness of the layer is 200 μm.

The results of high temperature thermal cycling experiments at 1150 °C show that when the peeling area of the ceramic layer 2 of the traditional thermal barrier coating exceeds 30%, the surface of the thermal barrier coating with a tree root-like structure 1 at the interface has no peeling, showing excellent high temperature thermal cycling stability. sex. It shows that the interfacial tree root-like structure 1 can effectively improve the life and reliability of thermal barrier coatings. The 3D printing method for constructing a biomimetic structure to optimize the interface stability can also be extended to other related fields, and has good application value.

Example 3: The different implementation steps of this embodiment from the specific example 1 are that the imitation tree root structure 1 is deposited on the superalloy base layer 3 layer, and the adhesive layer 4 is not present. Others are the same as the specific embodiment 1.

After cleaning, degreasing and sandblasting of the superalloy base layer 3, a first-level bifurcated tree root-like structure 1 is constructed on the surface of the superalloy base layer 3 by the coaxial powder feeding laser 3D printing technology.

As shown in Fig. 3, the spacing S of each imitation tree root structure 1 is 5 mm, the height H is 100 μm, the bifurcation angle θ is 45°, the fractal length L1 is ₁₀₀ μm, the thickness T is 100 μm, the length L2 is 50 μm, and the composition It is NiCoCrAlY. In the process of coaxial powder feeding laser 3D printing, the rated power of the laser is 500W, the diameter of the laser beam spot is 70μm, the laser power is 80W, the powder feeding method is coaxial powder feeding, the powder feeding amount is 2g/min, and the scanning rate is 7mm/ s, the argon flow rate is 5L/min. Finally, the YSZ ceramic layer 2 is deposited on the interface between the bonding layer 4 and the imitation tree root structure 1 by the atmospheric plasma spraying method, and the thickness of the layer is 200 μm.

1150 ℃ high temperature thermal cycle results show that when the peeling area of the ceramic layer 2 of the traditional thermal barrier coating exceeds 30%, the thermal barrier coating of this structure only has lateral cracks at the interface, but no ceramic layer 2 peels off, indicating that in the non-stick coating. Under the condition of the junction layer 4, the interface imitation tree root structure 1 can also effectively ensure the stability of the thermal insulation ceramic layer 2.

Example 4: This embodiment is the same as the implementation process of the specific example 1, the difference is that the superalloy matrix is a GH1015 iron-based superalloy matrix.

The results of high temperature thermal cycling experiments at 1150 °C show that when the peeling area of the ceramic layer 2 of the traditional thermal barrier coating exceeds 30%, the surface of the thermal barrier coating with a tree root-like structure 1 at the interface has no peeling, showing excellent high temperature thermal cycling stability. sex. It shows that the interfacial tree root-like structure 1 can effectively improve the life and reliability of thermal barrier coatings. The 3D printing method for constructing a biomimetic structure to optimize the interface stability can also be extended to other related fields, and has good application value.

Example 5: This embodiment is the same as the implementation process of the specific example 1, the difference is that the superalloy matrix is a GH3030 nickel-based superalloy matrix.

The results of high temperature thermal cycling experiments at 1150 °C show that when the peeling area of the ceramic layer 2 of the traditional thermal barrier coating exceeds 30%, the surface of the thermal barrier coating with a tree root-like structure 1 at the interface has no peeling, showing excellent high temperature thermal cycling stability. sex. It shows that the interfacial tree root-like structure 1 can effectively improve the life and reliability of thermal barrier coatings. The 3D printing method for constructing a biomimetic structure to optimize the interface stability can also be extended to other related fields, and has good application value.

Example 6: This embodiment is the same as the implementation process of the specific example 1, the difference is that the superalloy matrix is a cobalt-based superalloy matrix.

The results of high temperature thermal cycling experiments at 1150 °C show that when the peeling area of the ceramic layer 2 of the traditional thermal barrier coating exceeds 30%, the surface of the thermal barrier coating with a tree root-like structure 1 at the interface has no peeling, showing excellent high temperature thermal cycling stability. sex. It shows that the interfacial tree root-like structure 1 can effectively improve the life and reliability of thermal barrier coatings. The 3D printing method for constructing a biomimetic structure to optimize the interface stability can also be extended to other related fields, and has good application value.

The parts not covered above are applicable to the prior art.

Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration, not for limiting the scope of the present invention. Various modifications or additions may be made to, or substituted for, the specific embodiments described, without departing from the direction of the invention or going beyond the scope defined by the appended claims. Those skilled in the art should understand that any modification, equivalent replacement, improvement, etc. made to the above embodiments according to the technical essence of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A method for optimizing thermal barrier coating stability by constructing a bionic structure through 3D printing is characterized by comprising the following steps: the method comprises the following steps:

s1: the high-temperature alloy matrix layer is subjected to acetone solution immersion cleaning, ultrasonic cleaning and sand blasting pretreatment;

s2: constructing a tree root imitating structure on a high-temperature alloy matrix layer by adopting a coaxial powder feeding laser 3D printing technology;

s3: and depositing a YSZ ceramic layer on the tree root structure-imitated interface and the high-temperature alloy substrate layer by a plasma spraying method.

2. The method for optimizing the stability of the thermal barrier coating by constructing the bionic structure through 3D printing as claimed in claim 1, wherein: the tree root imitating structure in the step S2 is a multi-stage branched tree root imitating structure, the distance S of each branched tree root imitating structure is 1-20 mm, the height H is 50-500 mu m, the branching angle theta is 10-90 degrees, and the fractal length L is₁50 to 500 μm, a thickness T of 100 to 500 μm, and a length L₂50 to 500 μm and 1 to 3 stages in the number of branching stages.

3. The method for optimizing the stability of the thermal barrier coating by constructing the bionic structure through 3D printing as claimed in claim 2, wherein: the material of the imitated tree root structure is NiCoCrAlY or NiCrAlY.

4. The method for optimizing the stability of the thermal barrier coating by constructing the bionic structure through 3D printing as claimed in claim 1, wherein: the 3D printing technology in the step S2 adopts a fiber laser, the rated laser power is 500-1000W, the laser beam spot diameter is 50-200 μm, the laser power is 80-120W, the powder feeding amount is 2-8 g/min, the scanning speed is 5-15 mm/S, the argon gas is used for protecting a molten pool, and the flow rate is 3-6L/min.

5. A method for optimizing thermal barrier coating stability by constructing a bionic structure through 3D printing is characterized by comprising the following steps: the method comprises the following steps:

s1: the high-temperature alloy matrix is subjected to acetone solution immersion cleaning, ultrasonic cleaning and sand blasting pretreatment;

s2: depositing a bonding layer on the surface of the pretreated metal matrix by a plasma spraying or supersonic flame spraying method;

s3: constructing a tree root imitating structure on a bonding layer interface by adopting a coaxial powder feeding laser 3D printing technology;

s4: and depositing a YSZ ceramic layer on the interface of the bonding layer and the imitated tree root structure by a plasma spraying method.

6. The method for optimizing the stability of the thermal barrier coating by constructing the bionic structure through 3D printing as claimed in claim 5, wherein: the material of the bonding layer is NiCoCrAlY or NiCrAlY; the simulated tree root structure is made of the same material as the bonding layer.

7. The method for optimizing the stability of the thermal barrier coating by constructing the bionic structure through 3D printing as claimed in claim 6, wherein: the high-temperature alloy matrix is one of an iron-based high-temperature alloy matrix, a nickel-based high-temperature alloy matrix or a cobalt-based high-temperature alloy matrix.

8. The method for optimizing the stability of the thermal barrier coating by constructing the bionic structure through 3D printing as claimed in claim 5, wherein: the thickness of the bonding layer is 80-200 mu m.

9. The method for optimizing the stability of the thermal barrier coating by constructing the bionic structure through 3D printing as claimed in claim 5, wherein: the tree root imitating structure in the step S2 is a multi-stage branched tree root imitating structure, the distance S of each branched tree root imitating structure is 1-20 mm, the height H is 50-500 mu m, the branching angle theta is 10-90 degrees, and the fractal length L is₁50 to 500 μm, a thickness T of 100 to 500 μm, and a length L₂50 to 500 μm and 1 to 3 stages in the number of branching stages.

10. The method for optimizing the stability of the thermal barrier coating by constructing the bionic structure through 3D printing as claimed in claim 5, wherein: the fiber laser adopted in the 3D printing technology in the step S2 has the laser rated power of 500-1000W, the laser beam spot diameter of 50-200 mu m, the laser power of 80-120W, the powder feeding amount of 2-8 g/min, the scanning speed of 5-15 mm/S, the argon gas is used for protecting the molten pool, and the flow rate is 3-6L/min.

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