A method for evaluating damage of thermal barrier coating based on corrosion kinetics

Abstract

The present application relates to a kind of hot barrier coating damage evaluation methods based on corrosion kinetics, belong to hot barrier coating test technical field, the method includes: S1, carries out hot corrosion test, obtains the hot barrier coating test piece under different test conditions;S2, to hot barrier coating test piece is tested, obtains hot corrosion experimental data;S3, oxidation law analysis is carried out based on hot corrosion experimental data, constructs hot growth oxide layer thickening curve and thickening coefficient function;S4, carries out Arrhenius equation fitting, constructs hot growth oxide layer thickness prediction model;S5, generates theoretical oxidation data, and theoretical oxidation data and hot corrosion experimental data are checked;S6, constructs hot barrier coating damage evaluation model.The method can predict the thickness of hot growth oxide layer of hot barrier coating under different temperature and corrosion time, can realize the damage evaluation of hot barrier coating under different temperature and corrosion time, after verification, the method has good precision.

Description

Technical Field

[0001] This invention belongs to the field of thermal barrier coating testing technology, and in particular relates to a method for assessing thermal barrier coating damage based on corrosion kinetics. Background Technology

[0002] As the Chinese Navy ventures into the deep sea and the blue ocean, carrier-based aircraft operate in extreme, high-salt environments, placing stringent demands on aircraft and power plants. Oxidation and corrosion protection has become a core issue. Aerospace surface coating technology, as a crucial component of aerospace manufacturing technology, plays a vital role in protecting aircraft and power plants from oxidation and corrosion. By employing specific surface engineering techniques to prepare coatings with specific protective or functional properties on the surfaces of aircraft components, the application of these coatings significantly improves the performance, reliability, economy, service life, and survivability of aerospace products. Thermal barrier coatings, as a type of high-temperature protective coating, play a vital role in aero-engines, gas turbines, and internal combustion engines due to their excellent heat insulation, oxidation resistance, and high-temperature corrosion resistance. They can significantly reduce the surface temperature of high-temperature alloy parts, protecting hot-end components from corrosion and erosion by high-temperature gases. Thermal barrier coatings typically consist of a metal bonding underlayer and a ceramic top layer. The bonding underlayer is usually made of MCrAlY (M is Ni, Co, or Ni+Co) alloy, which mainly serves multiple functions such as transitional thermal mismatch, oxidation resistance, and corrosion resistance. The ceramic top layer is usually made of Y2O3-stabilized ZrO2, which mainly plays a role in heat insulation. Due to its excellent resistance to high-temperature oxidation, erosion resistance, and heat insulation properties, it has become one of the most advanced high-temperature protective coatings for aero-engines, gas turbines, and internal combustion engines at home and abroad.

[0003] The service environment of thermal barrier coatings is extremely complex, typically subjected to high temperatures and corrosive salts in media such as fuel gas and seawater. Therefore, high-temperature thermal corrosion has become one of the main forms of thermal barrier coating failure. Under the action of thermal corrosion, a thermally grown oxide layer forms at the interface between the top ceramic layer and the bonding substrate of the thermal barrier coating. As the corrosion time increases, the thermally grown oxide layer gradually thickens. However, the thickening of the thermally grown oxide layer leads to a decrease in the adhesion between the ceramic layer and the bonding substrate of the thermal barrier coating. When the thermally grown oxide layer reaches a certain thickness, partial peeling of the thermal barrier coating will occur, resulting in the failure of the thermal barrier coating.

[0004] Due to the complex thermal corrosion mechanism of thermal barrier coatings, existing technologies cannot assess the damage to thermal barrier coatings. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for assessing thermal barrier coating damage based on corrosion kinetics, thereby improving the efficiency of thermal barrier coating damage assessment. This method achieves rapid assessment of thermal barrier coating damage by constructing a thermal barrier coating damage assessment model.

[0006] In a first aspect, the present invention provides a method for assessing damage to thermal barrier coatings based on corrosion kinetics, comprising:

[0007] S1, conduct hot corrosion tests to obtain thermal barrier coating test pieces under different test conditions;

[0008] S2, Test the thermal barrier coating test specimen and obtain thermal corrosion test data;

[0009] S3. Based on thermal corrosion experimental data, the oxidation law was analyzed, and the thickness curve and thickness coefficient function of the thermally grown oxide layer were constructed.

[0010] S4. Fit the Arrhenius equation to construct a prediction model for the thickness of the thermally grown oxide layer.

[0011] S5. Theoretical oxidation data are generated based on the thermal growth oxide layer thickness prediction model, and the theoretical oxidation data are verified with the thermal corrosion experimental data.

[0012] S6. Construct a thermal barrier coating damage assessment model based on the thermal growth oxide layer thickness prediction model.

[0013] Furthermore, in S1, the thermal barrier coating test piece has a flat plate structure and is provided with clamping holes.

[0014] Furthermore, in S1, the substrate of the thermal barrier coating test piece is the second-generation nickel-based single-crystal high-temperature alloy DD6, and the thermal barrier coating is sprayed onto the substrate by plasma spraying.

[0015] Furthermore, in S3, the thickness increase curve of the thermally grown oxide layer is obtained through the relationship (Δh). m =K p t characterization, where Δh is the thickness of the thermally grown oxide layer in μm, K p is the thickness increase factor, t is the hot corrosion time, and m is a constant.

[0016] Furthermore, in S4, the expression for the Arrhenius equation is: Where K0 is the experimental parameter, Q is the activation energy in kJ / mol, T is the temperature in K, and R is the gas constant with a value of 8.314 J / (mol·K).

[0017] Furthermore, the steps for fitting the Arrhenius equation include taking the logarithm of the expression for the Arrhenius equation to obtain the relational expression. Based on the thickness increase coefficient K at different preset temperatures p Fit the relation to determine The values ​​of K0 and Q are used to obtain the fitted thickening coefficient function.

[0018] Furthermore, the thermally grown oxide layer thickness prediction model is constructed based on the fitted thickening coefficient function, and the expression for the thermally grown oxide layer thickness prediction model is as follows:

[0019] Furthermore, the expression for the thermal barrier coating damage assessment model is as follows: Where D is the thermal barrier coating damage value, n is the number of corrosion cycles, and Δh k h represents the thickness of the thermally grown oxide layer during the k-th corrosion. max This represents the critical thickness of the thermally grown oxide layer.

[0020] Furthermore, when assessing the damage of a thermal barrier coating using a damage assessment model, if D ≥ 1, the cumulative damage reaches 1, and the thermal barrier coating is deemed to have failed.

[0021] Furthermore, in the step of generating theoretical oxidation data based on the thermally grown oxide layer thickness prediction model, the experimental data from the thermal corrosion experiment data is imported into the thermally grown oxide layer thickness prediction model to obtain the theoretical oxidation data.

[0022] The beneficial effects of this invention are as follows:

[0023] The method described in this invention can predict the thickness of the thermally grown oxide layer of thermal barrier coatings at different temperatures and corrosion times, and can achieve damage assessment of thermal barrier coatings at different temperatures and corrosion times. After verification, the method has good accuracy.

[0024] This invention explores the thickening law of the thermally grown oxide layer in thermal barrier coatings during thermal corrosion and proposes a damage assessment method for thermal barrier coatings based on corrosion kinetics. This method provides technical support for damage assessment of thermal barrier coatings. Verification has shown that this prediction method has high accuracy, ensuring the stability and safety of thermal barrier coatings during service while avoiding economic losses caused by overly conservative lifetime calculations. It provides a theoretical basis for the design and development of thermal barrier coatings. Attached Figure Description

[0025] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. It is obvious that the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings.

[0026] Figure 1 This is a flowchart illustrating the principle of a thermal barrier coating damage assessment method based on corrosion kinetics according to the present invention.

[0027] Figure 2 for Figure 1 The schematic diagram of the thermal barrier coating flat plate test specimen in the embodiment shown is shown.

[0028] Figure 3 for Figure 1 A schematic diagram of the original microstructure of the thermal barrier coating in the embodiment shown, with a scale bar of 100 μm;

[0029] Figure 4 for Figure 1 The schematic diagram of the thickness of the thermally grown oxide layer on the thermal barrier coating test specimen in the embodiment shown is presented at 1100℃ for 100h, with the scale bar at 100μm.

[0030] Figure 5 for Figure 1 The schematic diagram of the thickness of the thermally grown oxide layer on the thermal barrier coating test specimen in the embodiment shown is presented at 1200℃ for 100h, with the scale bar at 100μm.

[0031] Figure 6 for Figure 1 The figures shown are fitting curves of the thermally grown oxide layer thickness at different preset temperatures in the embodiments illustrated.

[0032] Figure 7 for Figure 1 Fitting graph of the thermally grown oxide layer thickness coefficient in the embodiment shown;

[0033] Figure 8 for Figure 1 Error dispersion band diagram between actual and predicted values ​​of thermally grown oxide layer thickness in the illustrated embodiment;

[0034] The diagram is labeled as follows: 1-Clamping hole, 2-Ceramic layer, 3-Adhesive layer, 4-Base alloy, 5-Thermal grown oxide layer. Detailed Implementation

[0035] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0036] Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts disclosed in this invention.

[0037] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "installed," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of methods and systems consistent with some aspects of the invention as detailed in the appended claims.

[0039] This invention proposes a damage assessment method for thermal barrier coatings based on corrosion kinetics, which solves the problem that existing technologies cannot assess the damage of thermal barrier coatings due to the complex thermal corrosion mechanism.

[0040] Method Implementation Examples

[0041] This invention provides a method for assessing the damage of thermal barrier coatings based on corrosion kinetics, comprising:

[0042] S1, conduct hot corrosion tests to obtain thermal barrier coating test pieces under different test conditions;

[0043] S2, Test the thermal barrier coating test specimen and obtain thermal corrosion test data;

[0044] S3. Based on thermal corrosion experimental data, the oxidation law was analyzed, and the thickness curve and thickness coefficient function of the thermally grown oxide layer were constructed.

[0045] S4. Fit the Arrhenius equation to construct a prediction model for the thickness of the thermally grown oxide layer.

[0046] S5. Theoretical oxidation data are generated based on the thermal growth oxide layer thickness prediction model, and the theoretical oxidation data are verified with the thermal corrosion experimental data.

[0047] S6. Construct a thermal barrier coating damage assessment model based on the thermal growth oxide layer thickness prediction model.

[0048] In this embodiment, step S1 involves conducting a hot corrosion test to obtain thermal barrier coating test pieces under different test conditions. The thermal barrier coating test pieces are subjected to hot corrosion tests at different preset temperatures and corrosion times to obtain thermal barrier coating test pieces at different temperatures and different hot corrosion times. The thermal barrier coating test piece is a flat test piece with a clamping hole at the upper end. The substrate is a second-generation nickel-based single crystal high-temperature alloy DD6. The thermal barrier coating is sprayed onto the substrate alloy using a plasma spraying method.

[0049] The thermal barrier coating test specimen is a flat plate with a clamping hole at the top, and its structure is as follows: Figure 2 As shown in Table 1, the substrate is a second-generation nickel-based single-crystal superalloy DD6. The thermal barrier coating (TBC) was applied to the substrate alloy using plasma spraying. The initial thickness of the TBC was 190 μm-210 μm. The topmost YSZ (zirconia-stabilized yttrium) coating was approximately 50 μm thick, followed by a GZO (zirconia-stabilized gadolinium) coating with a thickness of approximately 100 μm, exhibiting a columnar structure. The bonding layer was a NiCrAlY alloy with a thickness of 40 μm-60 μm. The original microstructure of the TBC is shown in Table 1. Figure 3 As shown.

[0050] Table 1 Chemical composition of DD6, the second-generation nickel-based single-crystal superalloy

[0051] Mass percentage (wt%) 3.8 8.5 7.0 5.2 6.0 1.6 1.5 margin

[0052] In this embodiment, step S2 involves testing the thermal barrier coating test specimen to obtain thermal corrosion experimental data. The thickness of the thermally grown oxide layer on the thermal barrier coating test specimen at different temperatures and corrosion times is observed using a scanning electron microscope. Specifically, the cross-sections of the thermal barrier coating test specimen at different temperatures and corrosion times are ground, polished, and etched. Then, the microstructure of the corrosion layer is observed using a scanning electron microscope, and the thickness of the thermally grown oxide layer in the microscopic images is measured using Image-Pro Plus software (IPP) to obtain the thickness of the thermally grown oxide layer at different temperatures and corrosion times. The obtained data on the thickness of the thermally grown oxide layer are shown in Table 2. The thickness of the thermally grown oxide layer on the test specimen at 1100℃ for 100h is shown in Figure 4, and the thickness of the thermally grown oxide layer on the test specimen at 1200℃ for 100h is shown in Figure 5. The scale bar is 100μm for all values.

[0053] Table 2 Thickness of thermally grown oxide layer at different temperatures and corrosion times

[0054]

[0055] In this embodiment, step S3 involves analyzing the oxidation pattern based on thermal corrosion experimental data, constructing a thermally grown oxide layer thickness curve and a thickness coefficient function, and defining the thermally grown oxide layer thickness curve using the relationship (Δh). m =K p t characterization, where Δh is the thickness of the thermally grown oxide layer in μm, K p is the thickness increase factor, t is the hot corrosion time, and m is a constant.

[0056] Fitting the above equation, the resulting thickness curves of the thermally grown oxide layer at different preset temperatures, as well as the relationship between corrosion time, are shown below. Figure 6 As shown in the figure, the fitting curves show that the thermal growth coefficient of the oxide layer at 1100℃ is 0.49, and the thermal growth coefficient of the oxide layer at 1200℃ is 0.90.

[0057] In this embodiment, step S4 involves fitting the Arrhenius equation to construct a prediction model for the thickness of the thermally grown oxide layer; the expression of the Arrhenius equation is as follows: Where K0 is the experimental parameter, Q is the activation energy in kJ / mol, T is the temperature in K, and R is the gas constant, which is 8.314 J / (mol·K); taking the logarithm of the Arrhenius equation yields the following relationship. Based on the thickness increase coefficient K at different preset temperatures p Fit the relation to determine The values ​​of K0 and Q are used to obtain the fitted thickening coefficient function; the calculated thickening coefficients of the thermally grown oxide layer at two different preset temperatures are then used to refine the relationship. The fitting plot of the thickness increase coefficient of the thermally grown oxide layer is shown below. Figure 7 As shown, the values ​​of K0 and Q are obtained. This formula can be used to obtain the thickness increase coefficient of thermally grown oxide layers at any temperature.

[0058] Based on the thickness increase law and coefficient of thermally grown oxide layer, a thickness prediction model for thermally grown oxide layer is established. Substituting the calculated m, K0, Q, and R into the above formula, we get... This formula can be used to calculate the thickness of thermally grown oxide layers at any temperature and corrosion time.

[0059] In this embodiment, step S5 involves generating theoretical oxidation data based on the thermally grown oxide layer thickness prediction model, verifying the theoretical oxidation data against the thermal corrosion experimental data, and comparing the experimentally obtained thermally grown oxide layer thickness with the model-predicted thermally grown oxide layer thickness to verify the accuracy of the thermally grown oxide layer thickness prediction model. The specific operation is as follows: The theoretical oxidation data calculated by the prediction model in step four includes the thermally grown oxide layer thicknesses at 1100℃ for five corrosion times (10h, 20h, 50h, 100h, 200h, 500h) as 1.18μm, 1.54μm, 2.19μm, 2.86μm, 3.73μm, and 5.3μm, respectively; and at 1200℃ for the same five corrosion times (10h, 20h, 50h, 100h, 200h, 500h) as 2.17μm, 2.83μm, 4.03μm, 5.25μm, 6.85μm, and 9.73μm, respectively). The error band dispersion diagram between the model-predicted thermally grown oxide layer thickness (predicted value) and the experimentally obtained thermally grown oxide layer thickness (actual value) is shown in the figure below. Figure 8 As shown in the figure, the prediction error is within the 1.2-fold dispersion band, indicating good accuracy.

[0060] In this embodiment, step S6, the expression for the thermal barrier coating damage assessment model is: Where D is the thermal barrier coating damage value, n is the number of corrosion cycles, and Δh k h represents the thickness of the thermally grown oxide layer during the k-th corrosion. max This represents the critical thickness of the thermally grown oxide layer.

[0061] When D ≥ 1, i.e., the cumulative damage reaches 1, it indicates that the thermal barrier coating has failed. This model can be used to calculate the damage of the thermal barrier coating under any temperature and corrosion time, as well as the cumulative damage after the thermal barrier coating has been subjected to different corrosion times at different temperatures. It has important engineering value for damage assessment and life prediction of thermal barrier coatings during service.

[0062] Due to the extremely complex working environment of thermal barrier coatings, predicting and assessing damage during their service life is often very difficult. As a widely used coating in fields such as aero-engines, gas turbines, and internal combustion engines, the service life of thermal barrier coatings largely determines the lifespan of components such as engines, making it a crucial factor that must be considered. This invention proposes a corrosion kinetics-based method for assessing damage to thermal barrier coatings, providing a data foundation and methodological support for this purpose.

[0063] This embodiment establishes a damage assessment model for thermal barrier coatings based on corrosion kinetics. This model can predict the thickness of the thermally grown oxide layer of thermal barrier coatings at different temperatures and corrosion times. The model can achieve damage assessment of thermal barrier coatings at different temperatures and corrosion times. After verification, the method has good accuracy.

[0064] In this invention, thermal corrosion experiments are conducted on the target thermal barrier coating test specimens at different preset temperatures and corrosion times to obtain the thickness of the thermally grown oxide layer at different preset temperatures and corrosion times. Based on the experimental results and the thickening law of the thermally grown oxide layer, the thickening curves and thickening coefficients of the thermally grown oxide layer at different preset temperatures are fitted. Based on the Arrhenius equation, the thickening coefficient of the thermally grown oxide layer at any temperature is fitted, thereby establishing a prediction model for the thickness of the thermally grown oxide layer. Based on Miner's linear damage summation rule and the prediction model for the thickness of the thermally grown oxide layer, a damage assessment model for the thermal barrier coating is established.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A method for assessing damage to thermal barrier coatings based on corrosion kinetics, characterized in that, include: S1, conduct hot corrosion tests to obtain thermal barrier coating test pieces under different test conditions; S2, Test the thermal barrier coating test specimen and obtain thermal corrosion test data; S3. Based on thermal corrosion experimental data, the oxidation law was analyzed, and the thickness curve and thickness coefficient function of the thermally grown oxide layer were constructed. S4. Fit the Arrhenius equation to construct a prediction model for the thickness of the thermally grown oxide layer. S5. Theoretical oxidation data are generated based on the thermal growth oxide layer thickness prediction model, and the theoretical oxidation data are verified with the thermal corrosion experimental data. S6. Construct a thermal barrier coating damage assessment model based on the thermally grown oxide layer thickness prediction model. In S4, the expression for the Arrhenius equation is: ,in, For experimental parameters, The activation energy is expressed in kJ / mol. Temperature, in Kelvin (K). This is the gas constant, with a value of 8.314 J / (mol·K); The thickness prediction model for thermally grown oxide layers is constructed based on the fitted thickening coefficient function. The expression for the thermally grown oxide layer thickness prediction model is as follows: The expression for the thermal barrier coating damage assessment model is as follows: ,in This represents the damage value of the thermal barrier coating. For the number of corrosion cycles, For the first Thickness of the thermally grown oxide layer due to secondary corrosion. denoted as the critical thickness of the thermally grown oxide layer, and n as the number of corrosion cycles.

2. The method for assessing damage to thermal barrier coatings based on corrosion kinetics according to claim 1, characterized in that, In S1, the thermal barrier coating test piece is a flat plate structure, and clamping holes are provided on the thermal barrier coating test piece.

3. The method for assessing damage to thermal barrier coatings based on corrosion kinetics according to claim 2, characterized in that, In S1, the substrate of the thermal barrier coating test piece is the second-generation nickel-based single-crystal high-temperature alloy DD6, and the thermal barrier coating is sprayed onto the substrate by plasma spraying.

4. The method for assessing damage to thermal barrier coatings based on corrosion kinetics according to claim 1, characterized in that, In S3, the thickness curve of the thermally grown oxide layer is obtained through the relationship... Characterization, in which, The thickness of the thermally grown oxide layer is expressed in μm. For thickness increase coefficient, For hot corrosion time, It is a constant.

5. The method for assessing thermal barrier coating damage based on corrosion kinetics according to claim 4, characterized in that, The steps for fitting the Arrhenius equation include taking the logarithm of the expression for the Arrhenius equation to obtain the relational expression. Based on the thickness increase coefficient at different preset temperatures Fit the relation to determine middle and The value is used to obtain the fitted thickening coefficient function.

6. The method for assessing damage to thermal barrier coatings based on corrosion kinetics according to claim 5, characterized in that, When assessing the damage of a thermal barrier coating using a damage assessment model, if D ≥ 1, the cumulative damage reaches 1, and the thermal barrier coating is deemed to have failed.

7. The method for assessing damage to thermal barrier coatings based on corrosion kinetics according to claim 1, characterized in that, In the step of generating theoretical oxidation data based on the thermally grown oxide layer thickness prediction model, the experimental data from the thermal corrosion experiment data is imported into the thermally grown oxide layer thickness prediction model to obtain the theoretical oxidation data.

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