The article presents the research results on the impact of differences in input data values concerning materials used in thermal barrier coating systems on the results of simulations using the finite element method of temperature distribution and Huber-Mises equivalent stresses. Literature data on basic physical quantities important from the point of view of modelling, i.e. thermal conductivity coefficient, linear expansion coefficient, specific heat, density, Poisson fraction and Young's modulus, were reviewed. It has been shown that the data is characterised by a very wide range of values, which makes the issue of the final simulation results debatable. The study performed a simple statistical analysis of the available data for the 8YSZ compound, using the minimum, maximum, mean, and median values to simulate deadness. It was found that the results of the obtained simulations with the use of these data differ fundamentally from each other.

The article presents the research results on the impact of differences in input data values concerning materials used in thermal barrier coating systems on the results of the finite element method (FEM) simulation of temperature distribution and Huber-Mises equivalent stresses. This article focuses on the material parameters characterizing the intermediate layer and the base material. It was shown that, as in the case of the 8YSZ ceramic layer, the data are characterized by a very wide scatter of values. It was found that the results of the simulations obtained with the use of these data differ significantly from each other, depending on the adopted reference point, i.e. whether minimum, maximum, median or average values were adopted for the simulation. Therefore, considering the total differences in simulations resulting from the scattering of input data for the substrate material, interlayer and ceramic layer, it should be stated that it is possible to obtain virtually any simulation result.

Characterization of double ceramic layered thermal barrier coating (DCL MC) top-sur face of La2Zr2O7/8YSZ type under condition of hot corrosion in liquid deposits of sodium sulphate and vanadium oxides was described in this article. The base system used in investigations was deposited by atmospheric plasma spraying (APS) form feedstock powders of La2Zr2O7 and 8YSZ type on coupons from AMS 5599 Ni-based superalloys with NiCrAlY bond-coat. The hot corrosion test was performed at temperature 920 degrees C in two different variants of environment: 95 wt % Na2SO4 - wt 5 % V2O5 and 50 wt % Na2SO4 - 50 wt % V2O5. The time of exposure in low-vanadia environment was 57 hours and 4 hours in high-vanadia deposits. The range of investigations included characterization of top-surface of TBC system after test end with special attention to characterization of corrosion products determined by X-Ray diffraction method (XRD), as well as the characterization of chemical constituent of generated products by SEM/EDS analysis.

The degradation process of thermal barrier coatings (TBCs) such as monolayered La2Zr2O7, composite 50% La2Zr2O7 + 50% 8YSZ, and double-ceramic layer (DCL) La2Zr2O7/50% La2Zr2O7 + 50% 8YSZ/8YSZ was investigated. Coatings were deposited using the atmospheric plasma spraying (APS) process (ceramic layer and bond-coat) on the Ni-based superalloy substrate with Ni-22Cr-10Al-1Y bond-coat. The thickness of the ceramic top-coats in all cases were 300 µm. In the case of La2Zr2O7/8YSZ, the internal sublayer was built from 8YSZ powder whereas the outer from La2Zr2O7. Between both sublayers' "composite" a 50% La2Zr2O7 + 50% 8YSZ zone was present. The "composite" 50% La2Zr2O7 + 50% 8YSZ TBC system was sprayed from two different feedstock powders with equal weight ratios. In the first part of the investigation, the microstructural characterization of the TBCs was presented. The main goals were related to the characterization of the degradation processes in different TBC systems with special emphasis on the phenomenon in the thermally grown oxide (TGO) zone related to oxidation, and the phenomenon related to phase stability in ceramic top-coats as related to temperature influence. The oxidation test was carried out in air at 1100 °C for 500 h. In the second step of the investigation, the numerical simulation of the monolayered TBC 8YSZ and La2Zr2O7 systems was analyzed from the stress distribution point of view. Additionally, the two-layered TBC coating of the DCL type was also analyzed.

The accelerated decomposition of an Sm2Zr2O7+8YSZ system in the form of air plasma spraying (APS) thermal barrier coatings of composites, double ceramic layer (DCL), and functional graded system (FGS) types under hot corrosion conditions were analyzed. Hot corrosion tests were performed using liquid sodium sulfate salt deposits and then X-Ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersion spectroscopy (EDS) were performed to identify the reaction products. The obtained data indicated that negligible amounts of sulfates or oxysulfates were formed, but significant decomposition of pyrochlore Sm2Zr2O7 to the fluorite phase was detected. These phenomena were also observed in a much higher temperature range during pure oxidation tests, but the lowest decomposition temperature (920 degrees C) was observed in the sodium sulfate assisted process. The described observations were confirmed during similar tests and realized using model powder mixtures. Microstructural analysis of thermal barrier coatings (TBC) cross-sections revealed a complex decomposition process that was localized to areas near the Sm2Zr2O7 splats. The decomposition of the observed pyrochlore phase was mainly related to interactions between Sm2Zr2O7 and 8YSZ in accordance with the fluxing mechanism typical for the hot corrosion process of Ni-based superalloys. Additionally, the effect of eutectic Na-Sm-O was determined.

The determination of thermal resistance related to splat boundaries in composite TBC (thermal barrier coating) systems and expressed as splat-to-splat heat transfer coefficient was analyzed. Sm2Zr2O7 and conventional 8YSZ powders were used for coatings deposition by atmospheric plasma spraying. Two types of internal morphology were deposited: monolayered type (Sm2Zr2O7, 8YSZ) and composite TBCs (Sm2Zr2O7 + 8YSZ with weight ratios of 75/25, 50/50 and 25/75). The primary investigation was related to microstructural characterization of ceramic layers (pores and cracks architecture description), thermal diffusivity and conductivity characterization by laser flash analysis and theoretical models. The thermal conductivity was initially calculated on the basis of thermal diffusivity, heat capacity and density measurement as a function of temperature. Those values were corrected due to the presence of pores (microstructural analysis) and effective vales of thermal conductivity were calculated. These values were used as the basis for additional calculations based on the Hasselman-Johnson model of thermal conductivity for composite materials. Based on quantitative data from image analysis and porosity corrected thermal conductivity for monolayered and composite TBC systems, the thermal boundary conductivity (splat-to-splat heat transfer coefficient) was calculated as a function of temperature for Sm2Zr2O7 + 8YSZ composite systems.

The top coat of thermal barrier coatings systems based on lanthanum zirconate after corrosion tests in molten sodium sulphide salt at 920 and 970 degrees C was characterized in this article. Scanning electron microscopy and X-ray diffraction methods were used to analyse surface to-pography, as well as the phase composition of corrosion products. It was determined the La2Zr2O7 coatings exhibit very good corrosion resistance in liquid salt environments. The basic destruction process has been associated with the formation of a lanthanum sulphate phase. Additionally, an effect similar to thermal etching was observed in splat areas, as well as a cracks network formed in the interspalt areas.

The basic goal of this article was thermal diffusivity characterization of ceramic materials used in thermal barrier coating (TBC) systems for depositions of the insulation layer and characterization of the materials’ morphology and remanufacturing process. The base material was oxide 8YSZ (ZrO 2 × 8Y 2 O 3 ), which is usually dedicated to deposition of an insulating top layer in TBC systems. The data related to thermal properties such as thermal diffusivity and thermal conductivity are widely presented in the literature, but there is lack of information about the morphological form of investigated materials, and the presented results vary widely. Data on thermal properties based on the literature sources are inadequate for the real morphological form of materials used in the experiment (e.g., massive or single crystalline material vs. plasma-sprayed coatings), which consequently gives an unsatisfactory accuracy of the obtained numerical simulations by MES methods. This article presents the characterization of thermal diffusivity of the commercial 8YSZ ceramic material synthesized or remanufactured by different routes, which is investigated in the forms of pressed powder pellet (two commercial nano-sized powders with different morphologies), sintered pellets (one commercial powder, solid-state co-precipitated reacted powder of 8YSZ type), and a two-layered coating system of In625 + NiCrAlY/8YSZ type. The range of analysis included morphological investigations of different types of powders in initial conditions and after remanufacturing (sintering, thermal spraying) as well as the thermal diffusivity analysis by the laser flash method. The obtained data were corrected by porosity factor and compared to each other. The best similarity for obtained thermal diffusivity data was found for commercial powers of HOSP TM type after pressing and sintering processes and calculated (2-layered model) value of thermal diffusivity for two-layered system of In625/8YSZ TBS system. The results showed that there are significant differences in thermal diffusivity values for materials with different morphological forms.

The paper presents the results of numerical calculation of the temperature distribution and thermal stresses in model of two layered thermal barriers coatings of DCL type deposited on the superalloy coupons with NiCrAlY bond-coat. The variable parameter was the thickness of bond-coat layers. In all cases it was assumed that the bond-coat would be the NiCrAlY type coat obtained by plasma spraying, just as the outer insulating layer. The thickness of the bond-coat layer is 100 mu m to 300 mu m. As the substrate material, the In 625 nickel superalloy was adopted. The insulation layer of TBC systems was built from outer sublayer based on La2Zr2O7 (LZO) ceramic and internal layer was built from conventional 8YSZ. A total thickness of insulation layer was assumed as 300 mu m. Presented analysis showed that the overall thickness of bond-coat has important influence on the temperature distribution as well as the thermal stresses. The maximum temperature differences between extreme thickness value was calculated on the level of 50 degrees C.

The degradation process of La2Zr2O7 + 8YSZ composite thermal barrier coatings (TBC) was presented in this paper. These systems were deposited by air plasma spraying (APS) on AMS 5599 alloy and on a NiCrAlY bond-coat. A scope of tests consisting of isothermal oxidation in air atmosphere at 1100 degrees C for 500 h was performed. Detailed microstructural tests were carried out after 2, 10, 48, 175 and 500 hours of exposure. These tests included microstructure evaluation of a ceramic layer in all coating types, while particularly taking into account phenomena, which occur in a TGO (thermally growth oxide) zone. Evaluation of TGO zone growth was worked out and obtained results were compared with data for conventional TBC layers, which were deposited from 8YSZ powders and La2Zr2O7 respectively.

The paper presents the results of numerical calculations of the temperature distribution and thermal stresses in two systems of layered thermal barrier coatings (TBC) of DCL (double-ceramic-layer) type deposited on the In625 Ni-based superalloy by atmospheric plasma spraying (APS). Conventional monolayered TBC obtained from 8YSZ (6-8% wt. Y(2)O(3)xZrO(2)) and LZO (La2Zr2O7) powders with an insulation layer thickness of 300 mu m was used as the reference material. Numerical analysis was applied to the DCL TBC systems in which the external ceramic layer was obtained from LZO powder, while the internal layer was a 8YSZ zone. The thickness of both types of ceramic sublayers was a variable parameter. In all cases it was assumed that the bond-coat would be the NiCrAlY type of coating obtained by atmospheric plasma spraying. The thickness of the bond-coat layer was 200 microns. The starting point was a TBC system with the same thickness of both zones (150 mu m each), while further variants included coatings with the following mutual ratios of thickness of both materials (sub-layers): 20/80, 30/70, 50/50, 70/30 and 80/20. The purpose of these analyses was to determine the optimum value of the thickness ratio of individual ceramic zones in DCL coatings, not only from the point of view of the insulation effect, but primarily the state of stresses determining the durability of the entire TBC system. Numerical analysis of stress and temperature distribution indicates that the life cycle of DCL coatings should be strongly dependent on the thickness ratio of ceramic zones LZO and YSZ, while the two-layer coatings show better aggregate insulation characteristics and related stress states.

The degradation process of La2Zr2O7 thermal barrier coatings (TBC) was presented in this paper. This system was deposited by air plasma spraying (APS) on AMS5599 alloy and on a NiCrAlY bond-coat. A scope of tests consisting of isothermal oxidation in air atmosphere at 1100 degrees C for 500 h was performed. Detailed microstructural tests were carried out after 2, 10, 48, 175 and 500 hours of exposure. These tests included microstructure evaluation of a ceramic layer in both coating types, while particularly taking into account phenomena, which occur in a TGO (thermally growth oxide) zone. Evaluation of TGO zone growth was worked out and obtained results were compared with data for conventional TBC layers, which were deposited from 8YSZ powders.

The paper presents the results of numerical calculations of temperature and thermal stress distribution in thermal barrier coatings deposited by thermal spraying process on the nickel based superalloy. An assumption was made to apply conventional zirconium oxide modified with yttrium oxide (8YSZ) and apply pyrochlore type material with formula La 2 Zr 2 O 7 . The bond coat was made of NiCoCrAlY. Analysis of the distribution of temperature and stresses in ceramic coatings of different thicknesses was performed in the function of bond-coat thickness and the type of ceramic insulation layer. It was revealed that the thickness of NiCrAlY bond-coat has not significant influence on the stress distribution, but there is relatively strong effect on temperature level. The most important factor influenced on stress distribution in TBC system is related with type and properties of ceramic insulation layer.

Thermal barrier coatings (TBC) are the system build from ceramic insulation top-coat with internal bond-coat as an interlayer between ceramic and Ni-based superalloys substrate materials. The basic role of bond-coat is reduction of thermal strain between ceramic top-coat and metallic substrates. The second role is related to improving the oxidation resistance of metallic substrate. From thermal conductivity point of view, TBC’s system is characterized by three different materials. Usually, bond-coats and Ni-based superalloys were treated as materials with similar thermal properties such as specific heat, thermal diffusivity and thermal conductivity. Actually those materials can exhibit much higher divergences than expected. The aim of this article was the characterization of thermal diffusivity of bond-coats material of NiCrAlY type in the form of powders, massive alloy (obtained during sintering in an actual pressure of 15 MPa, in vacuum of 3 × 10−6 MPa, and at temperature 1050 °C with 2 h of exposure in press), and coating after air plasma spraying. Those studies should get the answer on the question how different morphology and processes impact on thermal diffusivity level of the same material.

The study covers some aspects of the issue of determination of mutual connections between the mechanical and material factors, as well the biological implant adaptation processes. The main objective of the operation was adopted to develop models of cementless hip prosthesis company Fitmore Zimmer, taking into account the heterogeneity of material properties of bone tissue. These models were loaded in particular stages of the human gate and then they were used for the analysis of stress changes. The identification of the relations between the mechanical properties of osseous tissue required the conducting of computer simulations by means of the Finite Element Method (FEM).

The article presents the results of research related to the impact of pretreatment plasma sprayed NiCrAlY coating on the kinetics of the oxidation. The analysis covered the shell subjected to thermal spraying. The test were performed at a temperature of 1000ºC and 1100ºC the samples were removed from the furnace after 25, 300, 500, 750 and 1000 hours. The investigations range included analysis of top surface of coatings by XRD characterization oxides formed types and microscopic investigations of coatings morphology.