Life Of Thermal Barrier Coatings Research Articles

Investigating the CMAS corrosion resistance and thermal cycling failure behavior of porous thermal barrier coatings with different morphologies prepared by plasma spraying

This study investigates the influence of two-phase powder feeding spacing on the thermal cycling and CMAS corrosion resistance of the thermal barrier coatings (TBCs). Porous thermal barrier coatings with varying microstructures were prepared using the embedded micro agglomerated particle (EMAP) coating preparation method, which is based on conventional yttrium stabilized zirconia (YSZ) coatings. The method involved changing the powder feeding spacing. TBCs' failure mode and microstructure are investigated under complex service conditions. The corrosion resistance, thermal cycling life, hardness, and elastic modulus of TBCs are investigated by thermal cycling-CMAS experiments and isothermal corrosion tests. The EMAP coating has a good service life in the thermal cycling-CMAS tests, with a lower hardness, lower elasticit modulus and larger surface roughness than conventional coatings. This research aims to provide a strategy to optimize structure for TBCs with excellent comprehensive performance.

Terahertz Nondestructive Measurement of Heat Radiation Performance of Thermal Barrier Coatings Based on Hybrid Artificial Neural Network

Effective control of the micro- and nanostructure of thermal barrier coatings is essential to enhance the thermal radiation performance of the coating, which helps to determine the remaining service life of the coating. This paper proposed a method to measure the radiation properties of thermal barrier coatings by terahertz nondestructive testing technique, using APS-prepared thermal barrier coatings as the object of study. Radiative properties were a comprehensive set of properties characterized by the diffuse reflectance, transmittance, and absorptance of the thermal barrier coating. The coating data in actual service were obtained by scanning electron microscopy and metallographic experiments, and the data were used as the simulation model critical value. The terahertz time-domain simulation data of coatings with different microstructural features were obtained using the finite-different time-domain (FDTD) method. In simulating the real test signals, white noise with a signal-to-noise ratio of 20 dB was added, and fast Fourier transform (FFT), short-time Fourier transform (STFT), and wavelet transform (WT) were used to reduce the noise and compare their noise reduction effects. Different machine learning methods were used to build the model, including support vector machine algorithm (SVM) and k-nearest neighbor algorithm (KNN). The principal component algorithm (PCA) was used to reduce the dimensionality of terahertz time-domain data, and the SVM algorithm and KNN algorithm were optimized using the particle swarm optimization algorithm (PSO) and the ant colony optimization algorithm (ACO), respectively, to improve the robustness of the system. The K-fold cross-validation method was used to construct the model to improve the adaptability of the model. It could be clearly seen that the novel hybrid PCA-ACO-SVM model had superior prediction performance. Finally, this work proposed a novel, convenient, nondestructive, online, safe and highly accurate method for measuring the radiation performance of thermal barrier coatings, which could be used for the judgment of the service life of thermal barrier coatings.

Structural evolution and enhanced thermal cycling life of HVAF-sprayed NiCrAlY bond coat modified by YSZ

Thermal barrier coatings with varied bond coat structures were deposited using high-velocity air fuel spraying. Highly hard YSZ particles are introduced into the NiCrAlY bond layer by accelerating to supersonic speeds at low temperatures to change the porous structure of the bond coat. We systematically increased the YSZ content in NiCrAlY bond coats and extensively investigated microstructure, oxidation behavior, thermal cycling life, and residual stress variation of the bond coats suing a combination of scanning electron microscopy, optical microscope, confocal Raman microprobe. Introduction of YSZ particles reduced the porosity of NiCrAlY bond coat from 2.69% to 0.45%, and altered the oxidation behavior of the bond layer. The NiCrAlY mixed YSZ composite structure induced the formation of a complex and thin thermal growth oxide layer on the bond coat during oxidation process, greatly alleviating and reducing the thermal stress generated of the coating and during the thermal cycling test. And the thermal cycling life of the NiCrAlY mixed YSZ composite structure coating is 2.8 times longer than that of the ordinary NiCrAlY coating. This finding highlights the significance of the bond coat structure in enhancing the service life of thermal barrier coatings.

Effect of Ti3C2Tx MXenes on the structure, morphology, fluorescence and temperature-sensitive properties of Eu3+-doped (YSZ)0.3-(YTaO4)0.7 rare-earth high-temperature ceramic powders

The rapid development of rare-earth fluorescent materials based on the fluorescence intensity ratio method allows the monitoring of internal temperature, stability and service life of thermal barrier coatings (TBCs). In this paper, Eu3+ doped (YSZ)0.3-(YTaO4)0.7 rare-earth ceramic materials was firstly prepared by chemical co-precipitation technique, and the doping content of Eu3+ was optimized by comparing its effect on morphology, luminescence and temperature sensitive performance of (YSZ)0.3-(YTaO4)0.7. Then the Ti3C2Tx MXene was subsequently blended into the optimal (YSZ)0.3-(YTaO4)0.7: Eu3+ powders by mechanical milling. The influence of Ti3C2Tx MXenes on the structure, morphology, fluorescence properties and temperature sensitivity of (YSZ)0.3-(YTaO4)0.7: Eu3+ powders was further investigated systematically. Results showed that (YSZ)0.3-(YTaO4)0.7: Eu3+ powders were compound of M′-YTaO4 and YSZ in tetragonal phase. The optimal doping content of Eu3+ is 1.5 mol%. The adding of Ti3C2Tx MXene did not affect the structure of (YSZ)0.3-(YTaO4)0.7:Eu3+ powders. After addition of Ti3C2Tx MXenes, part of (YSZ)0.3-(YTaO4)0.7:Eu3+ particles embedded in the middle of the accordion-shaped MXenes sheet, while the other part wrapped around MXenes. Ti3C2Tx MXenes could significantly improve the luminescence intensity, fluorescence lifetime and temperature-sensitive performance of (YSZ)0.3-(YTaO4)0.7: Eu3+powders. The optimal addition amount of Ti3C2Tx MXenes is 0.6 wt%. The absolute and relative sensitivities of MXene/(YSZ)0.3-(YTaO4)0.7:Eu3+ powders archived 2 times of (YSZ)0.3-(YTaO4)0.7: Eu3+ powders. Therefore, MXene/(YSZ)0.3-(YTaO4)0.7: Eu3+ could be used as temperature-indicating ceramic materials with highly efficient fluorescent properties for real-time monitoring of internal temperature of TBCs.

Reliability Evaluation of EB-PVD Thermal Barrier Coatings in High-Speed Rotation and Gas Thermal Shock

The uncertain service life of thermal barrier coatings (TBCs) imposes constraints on their secure application. In addressing this uncertainty, this study employs the Monte Carlo simulation method for reliability evaluation, quantifying the risk of TBC peeling. For reliability evaluation, the failure mode needs to be studied to determine failure criteria. The failure mode of high-speed rotating TBCs under gas thermal shock was studied by combining fluid dynamics simulations and experiments. Based on the main failure mode, the corresponding failure criterion was established using the energy release rate, and its limit state equation was derived. After considering the dispersion of parameters, the reliability of TBCs was quantitatively evaluated using failure probability and sensitivity analysis methods. The results show that the main mode is the fracture of the ceramic layer itself, exhibiting a distinctive top-down “step-like” thinning and peeling morphology. The centrifugal force emerges as the main driving force for this failure mode. The failure probability value on the top side of the blade is higher, signifying that coating failure is more likely at this location, aligning with the experimental findings. The key parameters influencing the reliability of TBCs are rotation speed, temperature, and the thermal expansion coefficient. This study offers a valuable strategy for the secure and reliable application of TBCs on aeroengine turbine blades.

Mechanical Loading Effect on Stress States and Failure Behavior in Thermal Barrier Coatings

Under service conditions, apart from the harsh temperature environment, mechanical loading also seriously affects the life of thermal barrier coatings (TBCs). A comprehensive understanding of the combined effects of thermo-mechanical loads can help to further reveal the failure mechanism of TBCs. In this work, a portion of a thin-walled circular pipe is intercepted for numerical analysis, and the interface is simplified as a sinusoidal curve. The dynamic growth of thermally grown oxide (TGO) is included into the model. A cohesive model is used for interfacial cracking analysis. The results show that the effects of tensile and compressive loads on the normal stress of the coating are not significant, while the effect on the shear stress of the coating is more obvious. In addition, the in-phase load will delay the occurrence of interfacial failure behavior, while an out-of-phase load can promote the failure. These results will help to better understand the effects of the coupling of mechanical and temperature loads and to provide support and guidance for the design of new TBCs structures in the future.

Effects of TGO growth on the interface stress distribution based on 3D pores in TBC ceramics layer

Yttria partially stabilized zirconia sprayed by the air-plasma-spraying method is widely used to protect superalloy substrates due to its unique thermomechanical properties, still, the formation and development of thermally grown oxide (TGO) often causes crack propagation in thermal barrier coatings and leads to accidents. In this paper, effects of the thickness of the TGO layer, porosity on the heat insulation properties, surface residual stress between the ceramic layer and the TGO layer of TBCs fabricated by atmospheric plasma spraying were studied. Finite element calculations were used to study the thickness of TGO layers with different porosities after thermal shock, the thermal insulation performance of coatings at high temperatures and the three-dimensional distribution of thermal strain, especially at the interface between the lower ceramic layer and upper TGO layer. The results show that when the porosity of the ceramic coating is approximately 24.35%, the thermal insulation performance and the maximum von Mises stress of the coating layers are optimized, and the coating has the most extended service life. Theoretically, this paper is of great significance in revealing the influence of porosity on the service life of thermal barrier coatings.

CMAS corrosion resistance of YSZ thermal barrier coatings enhanced by Pt–Al films

Corrosion of calcium magnesium aluminum silicate (CMAS) severely affects the durability of thermal barrier coatings (TBCs). In this study, 8 wt% Y2O3 partially stabilized ZrO2 (8YSZ) coatings were prepared using atmospheric plasma spraying (APS) technique, and a Pt–Al film was magnetron-sputtered onto the surface of the YSZ coating (Pt–Al-YSZ) to enhance its resistance against CMAS. The results indicated that the Pt–Al-YSZ coating displayed superior non-wetting performance against CMAS, as well as stronger resistance to CMAS corrosion. The results evidenced by Raman spectra and X-ray diffraction showed that phase transformation was smaller and corrosion depth was lower after CMAS corrosion at 1250 °C for 2 h. The thermal cycling test was also performed. The result demonstrated that the Pt–Al coating did not have a negative impact on the thermal cycling life of the YSZ TBCs. However, platinum tended to soften at high temperatures and became easily penetrated by molten CMAS. Therefore, it is necessary to further improve the strength of platinum layer to fully utilize its protective effect against CMAS attack.

Stiffening-resistant composite TBCs counteracting the substrate constraint effect during thermal exposure

Thermal barrier coatings (TBCs) endow metal components with an increased capacity to endure exposure to high temperatures. Plasma-sprayed TBCs exhibit excellent thermal insulation performance and are widely used in land-based thermal protection systems. However, plasma-sprayed TBCs are more prone to cracking during usage, significantly limiting their applications. The main issue is the sintering-induced stiffening that enhances the cracking driving force. In this work, stiffening-resistant TBCs were fabricated using a composite structure that counteracts the substrate constraint effect. First, the substrate constraint effect on the TBCs was studied based on the surface roughness. The results revealed that stiffening was the primary cause of substrate constraint-related failure. Two-dimensional (2D) interface gaps were spontaneously formed during thermal exposure, which could reduce stiffening by 20%. Moreover, the healing behavior of the 2D gaps was analyzed and used to explain the stiffening-resistant behavior. Finally, the effect of the newly formed 2D gaps on the lifespan of the TBCs was analyzed. Detailed simulations suggested that the newly formed 2D gaps were capable of reducing the strain energy release rate and led to the growth of large in-plane cracks. For future applications, it is necessary to fully take advantage of the newly-formed 2D gaps by avoiding their negative effects on TBC life span.

Thermal–Fluid–Solid Coupling Analysis on the Effect of Cooling Gas Temperature on the Fatigue Life of Turbine Blades with TBCs

The application of thermal barrier coatings (TBCs) can increase the blade’s operating temperature and fatigue life. Previous studies have neglected the effects of cooling gas temperature variations on the temperature field, stress field, and fatigue life of blades and TBCs. For this reason, this paper considers the inhomogeneity of the high-temperature gas inlet temperature, the internal cooling gas temperature, the periodicity of the external flow field, etc., and establishes a finite element model of the gas turbine blade with TBCs. Then, the life of the blade and the TBCs is predicted based on the Ncode 2020R2. Finally, the effect of the cooling gas temperature on the temperature, stresses, and life of the blade and the TBCs is analyzed. The results show that the fatigue life of the TBCs is lower than that of the blade, and the low-life region of the TBCs is located at the leading edge of the blade, which is consistent with the TBCs shedding region of the real blade and verifies the accuracy of the life prediction method in this paper. The fatigue life of the blade and TBCs firstly increases and then decreases with the increase in the cooling gas temperature, and the trend of the stress changes in the opposite direction. When the cooling gas temperature is increased from 573 K to 873 K, the minimum life of the blade is increased by 358.5%, and that of the TBCs is increased by 138.7%. The conclusions can provide guidance for the design of long-life turbine blades with TBCs.

Composite structure of YSZ embedded in NiCoCrAlTaY bond coat induces thin and multilayered Al2O3 film to extend the thermal cycle life of thermal barrier coatings

This study employs cold spraying technology to introduce supersonic-YSZ ceramic particle impacts onto the bond coat, enabling control the coating structure and interface morphology of the bond coat of thermal barrier coatings. The TBCs with YSZ ceramic particle-dispersed NiCoCrAlTaY bond coat were deposited and the dispersed distribution of YSZ ceramics changes the nucleation and growth behavior of oxides of the bond coat during high-temperature oxidation, which inducing the formation of thin and multilayered structure TGO that effectively suppresses the cracking phenomenon caused by concentrated oxide growth at coating interface during thermal cycling test at 1100 °C. The thermal cycling life of the specimens with NiCoCrAlTaY-mixed YSZ composite structure bond coat reached 68 days, which was 2.5 times longer than that of the specimens with APS NiCoCrAlTaY bond coat. Significantly enhancing oxidation resistance and service life of the coating.

Damage Grading Evaluation of Thermal Barrier Coatings under CMAS Corrosion

Thermal barrier coatings (TBCs) material has excellent high-temperature resistance and heat insulation performance, which plays a vital role in improving the working efficiency and running life of the engine. During the flight, the engine will inhale dust particles in the air. These particles are mostly from siliceous debris, which are usually called calcium magnesium aluminum silicate (CMAS). At present, CMAS corrosion has become one of the important problems affecting the service life of thermal barrier coatings. In this study, conventional yttrium oxide stabilized zirconia (YSZ) coatings and ytterbium oxide and yttrium oxide co-stabilized zirconia (YbYSZ) coatings were prepared by atmospheric plasma spraying. The two coatings were examined under thermal cycling-CMAS coupling conditions and divided into six life stages. The failure modes, CMAS permeation behavior, crack characteristics and mechanical properties of the two coatings at different life stages were evaluated systematically. The experimental results show that the YbYSZ coating has a longer life than YSZ coating under the thermal cycling and CMAS coupling condition, which increases by about 83% compared with the conventional YSZ coating. In the whole life stage, the porosity of YbYSZ coating is always higher than that of YSZ coating. The phase transition is not the reason for the failure and spalling of the coatings. The crack length of the two coatings showed an increasing trend, but the crack length of the YSZ coating was higher than that of the YbYSZ coating, and the crack density of the two coatings showed a “saddle shape”, which was more obvious for the YSZ coating. The YbYSZ coating shows better mechanical properties under the thermal cycling-CMAS coupling condition with the evolution of life.

Rare-earth cerates with a high coefficient of thermal expansion and excellent CMAS corrosion resistance obtained through high-entropy designing

As the demand for aero-engines with a high thrust-to-weight ratio has increased, the comprehensive performance requirements for thermal barrier coatings (TBCs) have become extremely challenging. Among them, the indicator that measures the service life of TBCs not only requires a high coefficient of thermal expansion (CTE) but also strong resistance to molten calcium-magnesium-aluminum-silicate (CMAS) corrosion. In this study, we used the solid-state method to prepare (La0.2Nd0.2Sm0.2Eu0.2Lu0.2)2Ce2O7 (5RLC), (La0.25Nd0.25Sm0.25Eu0.25)2Ce2O7 (4RLC), and Sm2Ce2O7 (SC) by sintering at 1700 °C for 10 h. By regulating the average radius and the variation of rare-earth ions through high-entropy designing, the lattice structure, micromorphology, element composition, CTE, and resistance to CMAS corrosion were systematically studied. The results showed that the bulk samples had defective fluorite structures, dense microstructures, and a uniform distribution of elements. At 1400 °C, the CTEs of 5RLC and 4RLC were 12.14 × 10−6 K−1 and 12.45 × 10−6 K−1, respectively. After 20 h of CMAS corrosion at 1300 °C, the thickness of the product layers was only 9.73 μm and 10.80 μm for 5RLC and 4RLC, respectively. In this study, we combined the high coefficient of thermal expansion and excellent CMAS corrosion resistance of 5RLC and 4RLC and found that they can maintain a good service life.

Life Analysis of TBC on an Aero Engine Combustor Based On In-Service Failures Data

TBC (Thermal Barrier Coatings) mostly find application in the combustion sections of aircraft turbine engines. With the demand for fuel economy and increased power, combustion temperatures are approaching the design limits of the metal alloys from which hot end components are made. Modern TBCs are required to not only limit heat transfer through the coating but to also protect engine components from oxidation and hot corrosion. When a TBC fails, it exposes the underlying substrate to very high gas temperatures and the life of the component gets reduce drastically. With a failed TBC, a component can even fail within its prescribed service life. This is an airworthiness issue. So it is essential to estimate the TBC life accurate possibly to ensure airworthiness of the aircraft at any given time. Premature failure are observed in the TBC applied over combustion section of a turboprop engine. The engine is 800 shp class and it powers a commuter aircraft. The objective of this paper is to find out mean life of the coating by life data analysis. The data has been fitted to Weibull distribution. The Weibull parameters have been discussed which highlights the dominating cause for TBC failure and hence suggestion for life improvement of TBC system has also been made. The need for TBC system redesign has been emphasized. In addition to this, it also presents a comparison between different users/ operators.

Nondestructive Evaluation of Thermal Barrier Coatings’ Porosity Based on Terahertz Multi-Feature Fusion and a Machine Learning Approach

Thermal barrier coatings (TBCs) play a crucial role in safeguarding aero-engine blades from high-temperature environments and enhancing their performance and durability. Accurate evaluation of TBCs’ porosity is of paramount importance for aerospace material research. However, existing evaluation methods often involve destructive testing or lack precision. In this study, we proposed a novel nondestructive evaluation method for TBCs’ porosity, utilizing terahertz time-domain spectroscopy (THz-TDS) and a machine learning approach. The primary objective was to achieve reliable and precise porosity evaluation without causing damage to the coatings. Multiple feature parameters were extracted from THz-TDS data to characterize porosity variations. Additionally, correlation analysis and p-value testing were employed to assess the significance and correlations among the feature parameters. Subsequently, the dung-beetle-optimizer-algorithm-optimized random forest (DBO-RF) regression model was applied to accurately predict the porosity. Model performance was evaluated using K-fold cross-validation. Experimental results demonstrated the effectiveness of our proposed method, with the DBO-RF model achieving high precision and robustness in porosity prediction. The model evaluation revealed a root-mean-square error of 1.802, mean absolute error of 1.549, mean absolute percentage error of 8.362, and average regression coefficient of 0.912. This study introduces a novel technique that presents a dependable nondestructive testing solution for the evaluation and prediction of TBCs’ porosity, effectively monitoring the service life of TBCs and determining their effectiveness. With its practical applicability in the aerospace industry, this method plays a vital role in the assessment and analysis of TBCs’ performance, driving progress in aerospace material research.

Prolonged thermal durability of plasma-sprayed lanthanum hexaluminate thermal barrier coating by optimizing crystallinity

LaMgAl11O19 (LMA) with magnetoplumbite structure has been identified as a potential candidate for the next generation of thermal barrier coatings (TBCs). However, the as-sprayed LMA coating presents a large amount of amorphous phase originating from the rapid quenching from the molten droplets, which may compromise the reliability of coating during high-temperature service. A logical approach to improve LMA TBC life, therefore, is to enhance its crystallinity. In the present study, three LMA powders with different particle size distributions (fine, medium and coarse feedstocks) were utilized to deposit TBCs to investigate whether the thermal durability of LMA can be improved by increasing particle size. It was based on a hypothesis that large particle size can decrease the melting degree of in-flight particles and thus result in high crystallinity of as-sprayed LMA coating, making less recrystallization stress to enhance the thermal shock resistance of LMA coating. Results show that prolonged thermal cycling durability can indeed be achieved by increasing particle size. However, excessive particle size could lead to higher porosity derived from unmelted particles, which function as the weak regions for the coating system, thereby damaging the structural integrity and adhesive strength between the topcoat and bond coat. This could cause microcrack linking when the accumulated thermal stress exceeds its fracture toughness under consecutive heating-cooling cycles despite its higher crystallinity. Concerning the coating fabricated by medium powder, it achieves the optimal balance of crystallinity and structure integrity, resulting in the longest thermal cycling lifetime. The results provide guidance for the development and design of high thermal durability LMA TBCs. When optimizing the recrystallization stress within the coating, attention should be paid to improving its bonding strength simultaneously.

High temperature creep study on thermally grown oxide by tensile combined with a digital image correlation method

A thermally grown oxide (TGO) layer usually generates at the interface between the ceramic coating and the bond coating during the long-term high temperature service. TGO creep can affect the service life of thermal barrier coatings. In this paper, a dense TGO layer with a thickness of 4 μm is formed on the surface of the PtAl bond coating. The high-temperature creep behavior of the TGO layer is investigated by tensile combined with a digital image correlation method. The creep mechanism of TGO at 750 °C–950 °C is dislocation creep (stress exponent ∼4, and creep activation energy of 706–815 kJ/mol). The creep strain rate of TGO at 750 °C–950 °C is in the range of 4.7 × 10−6 s−1–4.7 × 10−4 s−1. The failure behavior of the TGO layer is significantly affected by temperature and applied stress. As the temperature and stress increase, the surface vertical cracks initiate at the TGO surface and propagate to the interface of TGO/PtAl bond coating, leading to the delamination and cracking of TGO layer.

Phase transformation failure in YSZ TBCs induced by component-dependent CMAS corrosion

Generally, CMAS corrosion is a key factor leading to the spalling failure in thermal barrier coatings (TBCs). Figuring out the component-dependent failure mechanism is the premise to improve the service life of TBCs. Here, CMAS corrosion behaviors with different Ca/Si components have been investigated through analyzing microstructure evolution in 8-YSZ coatings by EB-PVD. Capillary force from the gap between columnar crystals could accelerate the infiltration speed of the molten CMAS, leading to a fully populated coating with lower strain tolerance in 4 h. Subsequently, CMAS infiltration in the coatings led to preferential dissolution of yttrium ions and precipitation of yttria lean YSZ, and secondary CMAS phases. The corrosiveness of CMAS could be further tailored by optical basicity and viscosity. TBC failure could be enhanced in high-Ca case, resulting in the morphology evolution from columnar crystals to coarsening grain structures. Raman spectra indicates CMAS corrosion with high-Ca content will facilitate the phase transformation of t-YSZ to harmful monoclinic phase. In addition, DFT calculation demonstrates Ca doping into 8-YSZ will make monoclinic phase more stable and generate a 4.1 % volume expansion from the view point of energy. Consequently, the combination of the above low strain tolerance, new phases and volume expansion will accelerate the harmful morphology evolution. This work provides direct insight into the failure mechanism of CMAS corrosion and paves the way to design of new TBCs.

CMAS corrosion resistance, thermal shock resistance and numerical simulation of novel surface micromesh thermal barrier coatings

Thermal barrier coatings (TBCs) are widely used as insulating layers to protect the underlying metallic structure of gas turbine blades. However, the thermal cycling performance of TBCs is affected by their complex working environments, which may shorten their service life. Previous studies have shown that preparing a mesh structure in the bonding layer can relieve thermal stress and improve the bonding strength, thereby prolonging the service life of TBCs. In this paper, a micromesh structure was prepared on the surface of the bonding layer via wet etching. The microstructure and failure mechanism of the micromesh TBCs after CMAS (CaO-MgO-Al2O3-SiO2) thermal erosion were investigated. Numerical simulation was combined with thermal shock experiments to study the stress distribution of the micromesh-structured TBCs. The results showed that the circular convex structure can effectively improve the CMAS corrosion resistance and thermal shock resistance of TBCs.

Mechanical properties of (ZrYTaErTi)O composites

Good fracture toughness can prolong the service life of thermal barrier coatings under thermomechanical loading. Yttria-stabilised zirconia (YSZ) and other novel thermal barrier coatings have low fracture toughness and are thus prone to spalling failure. High-entropy ceramics can provide coatings with excellent mechanical properties. In this study, (ZrYTaErTi)O composites were prepared via a solid-state reaction method based on the concept of high-entropy ceramics. The high-temperature phase stability and mechanical properties of the material were characterised and analysed by X-ray diffraction (XRD) and microindentation tests. The results showed that (Zr0.544Y0.114Ta0.114Er0.114Ti0.114)O had the best fracture toughness, which is 1.5 times higher than that of YSZ, of the ceramics prepared with different composition ratios. At the same time, the effects of grain size and the introduction of a second phase on the fracture toughness of the composites were analysed. This study provides guidance for future research on improving the mechanical properties of novel thermal barrier coating materials.