Beam Physical Vapor Deposition Technique Research Articles

Optimization design and performance improvement of ther-mal barrier coating (TBC) system

Thermal Barrier Coatings (TBC) technology has become one of the key technologies to improve the performance and prolong the service life of gas turbine and other high temperature equipment. In this study, the selection of materials, coating methods, the influence of environmental factors on the performance of TBC system and the thermal stress analysis and optimization strategy are discussed, improve the overall performance and stability of TBC system. TBC coatings were efficiently prepared by the use of Nikolay bonding layer and stabilized zirconia as top ceramic materials, combined with electron beam Physical vapor deposition (EB-PVD) and plasma spraying (APS) techniques. In addition, the thermal stress model was established by FEA, and the thermal stress distribution of TBC system under extreme operating conditions was analyzed in detail, to reduce thermal stress concentration and improve the thermal barrier effect of the coating. Finally, through the establishment of TBC system life prediction model and in-depth analysis of the failure mechanism, a series of preventive measures and performance improvement strategies are proposed, it provides theoretical basis and practical guidance for coating design of gas turbine and other high temperature equipment.

Thermal shock behavior of novel (Yb0.1Gd0.9)2Zr2O7 thermal barrier coatings with a Cr modified (Ni, Pt)Al bond coat

The durability of thermal barrier coatings (TBCs) is significantly influenced both by the ceramic top coat and the bond coat. In this study, novel YbGdZrO ceramic coats were deposited on the surfaces of three types of Cr-modified (Ni, Pt)Al bond coats via electron beam physical vapor deposition (EB-PVD) technique. These Cr-modified (Ni, Pt)Al bond coats were fabricated by magnetic sputtering Cr onto the (Ni, Pt)Al bond coats with varying sputtering times of 30, 60, and 90 min. The results indicates that the thickness of the Cr-modified layer increases with the extension of sputtering time. A short deposition time of 30 min is adequate for achieving an appropriate Cr content in the (Ni, Pt)Al bond coats, which ensures selective oxidation of Al element within the bond coat and further enhances the metallurgical interfacial bonding strength with the ceramic coat by adapting to the concentration gradient diffusion. However, as the sputtering time is extended to 60 and 90 min, α-Cr begins to form in the Cr-modified (Ni, Pt)Al bond coats, which negatively affects the oxidation resistance of the bond coat. Consequently, the thermal shock life of the TBCs samples is significantly reduced with increasing sputtering time. The longest thermal shock lifetime is obtained on the bond coat with Cr plating time of 30 min owing to a differing thermally grown oxide formation and failure mechanism.

Thermal shock behavior of EB-PVD thermal barrier coatings based on YSZ ceramic coat and (Ni, Pt)Al metallic bond coat

Three different chemical vapor deposition (CVD) aluminizing processes were adopted for preparing of (Ni, Pt)Al metallic coatings, whose microstructure, element content, phase constituent and gas hot corrosion performance were evaluated and comparatively analyzed. YSZ ceramic coatings were subsequently fabricated via electron beam physical vapor deposition (EB-PVD) technique on top of the optimized (Ni, Pt)Al bond coat surface, and thermal barrier coating (TBC) specimens were subjected to 1373 K long-term thermal shock. The surface of aluminized sample with a single external reaction generator is relatively compact, and no defects such as micropores and microcracks are observed. Only a large number of protruding sediments are detected at grain boundary as well as the degree of rumpling and cross-links of these sediments is more obvious. A large amount of Pt is enriched at that grain boundary, while elemental content of Al is lower at the same location. Meanwhile, such sample basically displays β-(Ni, Pt)Al phase, and only three very weak diffraction peaks belonging to ζ-PtAl2 coexist. After long-term thermal shock, the exposed region of bond coat shows two kinds of micro-morphology. The biggest distinction between them is that the composition of Pt and Al elements is evidently different. The interfacial separation of TBCs is mainly concentrated at interface between thermally grown oxide (TGO) and bonding layers, and a very small amount of TGO layer is merely adhered to bond coat surface. It demonstrates that TGO layer is densified and thickened with the extension of thermal exposure period, and then the mismatching of thermal expansion between Al2O3 and (Ni, Pt)Al bond coat occupies the dominant factor. In addition, the grain boundary ridges and undulations on bonding layer surface can also induce accumulation of the tensile stress and further accelerate degradation of the critical interlayer interface during cooling stage of thermal shock.

Thermal cycling behavior of EB-PVD NiAlHf coating via laser shock peening treatment

NiAlHf coatings prepared via the electron beam physical vapor deposition (EB-PVD) technique were modified using the laser shock peening (LSP) technique. The surface states and microstructures, including phase composition, crystal defects, and reactive element distribution, were characterized and analyzed. The coatings were subjected to 1200 °C for 100 thermal cycles. The high-temperature service performance of the coatings was evaluated by comparing the growth behavior of the thermally grown oxide (TGO) and the coating peeling. The results showed that after 100 thermal cycles, the samples without LSP treatment exhibited oxide film damage and large-area internal oxidation, nearly resulting in coating failure. In contrast, the samples treated by LSP demonstrated intact oxide films and strong antioxidant properties. The modified coating surface is flat, high-density dislocation is introduced, and the coating grain is refined, providing more diffusion channels for the selective oxidation of Al elements. This refinement of the grain structure provides a prerequisite for the uniform growth of thermal TGO and significantly reduced TGO spallation. In addition, the influence of the reactive elements in the substrate on the growth behavior of TGO was necessary to be considered. LSP is a promising technology for improving the thermal cycling performance of NiAlHf coatings.

EBM Technique Study on Microstructural Characterization of Al-Zr-N Coating

Through the implementation of the electron beam physical vapour deposition (EB-PVD) technique, an aluminium zirconium nitrate (Al-Zr-N) coating has been created in the current work on high speed steel (E19) substrates. Through the use of X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), nano indentation, and scratch tests, the structural morphological and mechanical properties of the substrate are investigated. The cause of tension relaxation and vacancy concentration is explained by the fluorite phase's lattice constant decreasing with rising deposition temperature. As the temperature of the substrate rises, the coating's increased surface roughness is explained by an increase in crystallite size [1]. TBCs are frequently applied to metal substrates using the Atmospheric Plasma Spraying (APS) and Electron Beam Physical Vapour Deposition (EB-PVD) methods. For the next generation of turbine engines, the high costs and relatively high thermal conductivities of EB-PVD coatings, as well as the short thermal lifetime of APS coatings, are significant drawbacks. Suspension Plasma Spraying (SPS) was evaluated in this study to enhance the thermal properties of TBC. The SPS process enables the creation of columnar micro-structures that are easily adjustable in terms of thermal conductivity and columnar structure compaction.

Post-deposition annealing effect on the structural and electrical properties of ytterbium oxide as an alternative gate dielectric

The possibility of ytterbium(III) oxide, one of the rare earth oxides, to replace silicon dioxide used as the gate dielectric is discussed in this article. For such a replacement, it is primarily necessary to understand the physical and chemical characteristics of ytterbium(II) oxide as a candidate, such as bond structure, electronic structure, band offsets with Si, dielectric constant, interfacial states and defect behavior. The effects of structural and electrical features of ytterbium(III) oxide-based MOS capacitors on device performance are investigated. The electron beam physical vapor deposition (EBPVD) technique was used for the deposition of ytterbium(III) oxide thin films. The 122 nm thick Yb2O3 thin film was annealed at four different temperatures (200 °C, 400 °C, 600 °C, and 800 °C) in nitrogen environment. The crystallite size determined from the as-deposited sample as 15 nm is the lowest. As expected, crystallite sizes increased as a result of increasing annealing temperature. The presence of Yb2+ oxidation states increased in the region close to the interface or at the interface. The binding energies of the Yb 4d and O 1s spectra increased with increasing depth into the films. In the O 1s spectra, the organic bonds on the surface first decreased and then increased with increasing annealing temperature. Silicate formation at the interface was determined for the annealed samples. This affected the electrical performance of the capacitors. The calculated dielectric values range from 12.1 to 15.8. Interface level densities were found in the order of 1012 cm−2 and it did not exhibit frequency-dependent behavior. The calculated values for the effective charge densities varied between −24.19 × 1011–7.03 × 1011 cm−2. It has been determined that mostly negative charges are trapped more for different capacitors. Finally, Fermi energy level, dopant concentration, diffusion potential and barrier heights were calculated.

Fabrication of enriched 170Yb2O3 thin targets for studying asymmetric fission in sub-lead mass region

Owing to the highly oxidizing and chemically active nature of rare-earth elements, preparation of isotopically enriched thin targets of rare-earth metals has been a challenging task. The successful fabrication of thin films of enriched 170Yb2O3 on carbon backing with areal density in the range 160–200 μg/cm2 and approximately 22μg/cm2, respectively is described here along with the various challenges encountered during the fabrication and new optimized operational parameters. On account of limited availability and high cost of the enriched 170Yb due to its extremely low natural abundance, many iterations were attempted with natural ytterbium to optimize the evaporation setup and its associated parameters. The electron beam physical vapour deposition technique in ultra-high vacuum facility was found suitable for the evaporation and a specially designed cylindrical tantalum crucible was used to further improve the collection efficiency. Optimization trials were carried out with the deposition parameters reported in the literature but a considerably high concentration of tantalum was noticed in the films. This impurity could drastically contaminate the experimental data and needed to be minimized. The present work reports a new set of deposition parameters optimized for the fabrication of thin ytterbium oxide films with the tantalum contamination reduced to indiscernible amounts. The final evaporation of enriched 170Yb2O3 was carried out with a 30 mg of the material that was found to be fully consumed. Various characterization techniques were carried out to ascertain thinness, purity and the elemental composition of the films viz. Rutherford Backscattering Spectroscopy (RBS) and Energy Dispersive X-ray Spectroscopy (EDS). These measurements corroborated the achieved optimization of deposition parameters with negligible contribution of impurities in the films. The purity and stability of the films were further established with a good quality of data obtained after irradiation with 28Si beam.

Deposition of CaZrO3 thin films by EB-PVD: Effects of substrate on the composition, the structure, the morphology and the optical properties

CaZrO3 thin films have been prepared using the electron beam physical vapor deposition (EB-PVD) technique. To study the effect of the substrate's nature on the physical properties of the films, films of calcium zirconate were grown onto two different substrates; amorphous glass and single-crystalline silicon under the same deposition conditions. It was found that the nature of the substrate affects the structure, morphology, and optical properties of the prepared films. The composition of elements and the thicknesses were analyzed by Rutherford backscattering spectrometry. It was found that films grown onto glass substrates show homogeneous single layers without inter-diffusion, however, an interfacial layer was detected between the substrate and the CaZrO3 film for the films deposited on silicon. The crystalline structure and the purity of the prepared thin films were investigated by X-ray diffraction. The morphology and the surface roughness of the prepared thin films were investigated using scanning electron microscopy and atomic force microscopy. The morphology of the growing films was found to be strongly dependent on the substrate surface, as the films on the silicon substrate exhibit relatively smoother surfaces than those on glass. UV-Visible diffuse reflectance spectroscopy reveals that thin films deposited on silicon show the highest optical bandgap.

Oxidation and hot corrosion resistance of HVOF/EB-PVD thermal barrier coating system

Hot corrosion and oxidation cause very destructive damage in thermal barrier coatings (TBCs) during service conditions. In hot corrosion, TBCs exposed to molten salts lose their integrity easily due to the phase transformations while oxygen easily penetrates from the TBCs to bond coats and forms thermally grown oxide (TGO) layer which causes higher stresses at the interface of bond and top coating. In the current study, CoNiCrAlY powders were sprayed by high-velocity oxygen fuel (HVOF) technique on Inconel 718, and then yttria-stabilized zirconia (YSZ) and YSZ/Gd2Zr2O7 ingots were deposited by electron beam physical vapor deposition (EB-PVD) technique on the bond coated substrates. Isothermal oxidation tests were carried out at 1000 °C for 8, 24, 50, and 100 h, while hot corrosion tests were carried out at 1000 °C in the presence of NaCl, Na2SO4, and V2O5 molten salts with 5, 10, 15, and 20 h cycles. The produced coatings, as well as the oxidation and hot corrosion test results, were examined using SEM, EDS, XRD, and image analysis techniques. After the tests, the Gd2Zr2O7 layer was found to exhibit superior oxidation and hot corrosion performance as compared to the conventional YSZ TBC system.

Role of bovine serum albumin in the degradation of zirconia and its allotropes coated 316L SS for potential bioimplants

Surface engineered materials are presently used in dental, orthopedic and cardiovascular applications made of titanium, cobalt-chromium, stainless steel alloys, etc. In this perspective, different phases of zirconia (ZrO2; henceforth ZrO2 allotropes) coatings (m-ZrO2, t-ZrO2 and c-ZrO2) were developed by electron beam physical vapor deposition (EBPVD) technique. ZrO2 allotropes obtained a smooth surface with a drastic reduction of human pathogenic bacterial adhesion. t-ZrO2 coating evolved higher surface hardness followed by c-ZrO2 and m-ZrO2 coatings. ZrO2 allotropes showed higher blood plasma protein adherence using a whole blood test. Whilst, the role of proteins in the degradation of ZrO2 allotrope coatings was examined in detail by electrochemical impedance spectroscopy (EIS) in the presence and absence of bovine serum albumin (BSA) in artificial blood plasma (ABP) solution.

Microstructure and Optical Properties of E-Beam Evaporated Zinc Oxide Films-Effects of Decomposition and Surface Desorption.

Zinc oxide films have been fabricated by the electron beam physical vapour deposition (PVD) technique. The effect of substrate temperature during fabrication and annealing temperature (carried out in ultra high vacuum conditions) has been investigated by means of atomic force microscopy, scanning electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. It was found that the layer deposited at room temperature is composed of Zn and ZnO crystallites with a number of orientations, whereas those grown at 100 and 200 C consist of ZnO grains and exhibit privileged growth direction. Presented results clearly show the influence of ZnO decomposition and segregation of Zn atoms during evaporation and post-deposition annealing on microstructure and optical properties of zinc oxide films.

Performance of single YSZ, Gd2Zr2O7 and double-layered YSZ/Gd2Zr2O7 thermal barrier coatings in isothermal oxidation test conditions

Oxidation is an inevitable failure mechanism under the operating temperature in gas turbines. To avoid negative effects of oxidation, ceramic-based materials having low thermal conductivity and high stability should be used to hot section components. In accordance with this purpose, thermal barrier coatings (TBCs) are used in order to increase the lifetime of gas turbine engine components that have not reached to desired levels yet. Yttria stabilized zirconia (YSZ) has been used as a conventional top coat material in TBCs. Increased the turbine inlet temperatures (TIT) promote to researchers to try higher stable material such as rare earth zirconates. In this study, CoNiCrAlY metallic powders were sprayed using a new emerging technique as called cold gas dynamic spray (CGDS) on Inconel 718 substrates. Single layer YSZ, Gd2Zr2O7 and double-layered YSZ/Gd2Zr2O7 were deposited by electron beam physical vapor deposition (EB-PVD) technique as top coat materials. In high temperature furnace, both TBC samples were isothermally oxidized at 1000 °C under different time periods. TBCs were examined as microstructural before and after oxidation tests. Thermally grown oxide (TGO) layer forming at the interface during oxidation were investigated and compared for each TBC systems. Oxidation and TGO growth behaviors were discussed.

Photo-Thermal Conversion Efficiency of Spectrally Selective Cr <sub>2</sub>O <sub>3</sub>/Cr/Cr <sub>2</sub>O <sub>3</sub> Multilayered Solar Absorber

Renewable energy is the alternative resource to deal with environmental problems and to satisfy the ever-increasing energy demand. Concentrating Solar Power (CSP) systems are valuable candidates to harness solar energy. CSP systems first convert solar radiation into thermal energy which is much easier and economical than storing electricity. The solar absorbing surface is the critical part of CSP systems, as it directly affects the efficiency of the solar thermal energy conversion into electricity. To achieve high conversion efficiency of incident light into heat, the solar absorber should be spectrally selective. To obtain this spectral selectivity, various designs such as absorbing semiconductor-metal tandems, composite films and multilayer interference stacks with multiple dielectric and metallic thin films have been used such as Cr2O3, Al2O3, HfO2, Ni, Cr, and Zr. However, their optical properties determine the efficiency of the energy conversion from the concentrated solar irradiation to the thermal energy recovered by the heat transfer fluid or nanofluid. This paper experimentally investigates on the photo-thermal conversion efficiency of Cr2O3/Cr/Cr2O3 multilayered selective solar absorber (SSA) deposited onto stainless steel substrates by using an electron beam physical vapor deposition technique. Interestingly, the fabricated Cr2O3/Cr/Cr2O3 SSA showed good photo-thermal conversion efficiency with a peak temperature exceeding 180 °C after an irradiation time of 2500 s; this obtained value is comparable to the performance of state-of-the-art SSA surfaces.

Effects of yttria content on the CMAS infiltration resistance of yttria stabilized thermal barrier coatings system

The effects of YO1.5 doping in yttria-zirconia based thermal barrier coatings (TBCs) against CMAS interaction/infiltration are discussed. The TBCs with an YO1.5 content ranging from 43–67 mol.% (balance ZrO2) were produced by electron beam physical vapor deposition (EB-PVD) techniques. The results reveal a trend of higher apatite formation probability with the higher free YO1.5 available in the yttria-zirconia system. Additionally, the infiltration resistance and amount of consumed coating appears to be strongly dependent on the YO1.5 content in the coating. The thinnest reaction layer and lowest infiltration was found for the highest produced 67YO1.5 coating. Complementary XRD experiments with volcanic ash/YO1.5 powder mixtures with higher yttria contents than in the coatings (80YO1.5 and pure YO1.5) also showed higher apatite formation with respect to increasing yttria content. The threshold composition to promote apatite-based reaction products was found to be around 50YO1.5 in zirconia which was proved in the coatings and XRD powder experiments. An YO1.5-ZrO2-FeO-TiO2 bearing zirconolite-type phase was formed as a reaction product for all the coating compositions which implicates that TiO2 in the melt acts as a trigger for zirconolite formation. This phase could be detrimental for CMAS/volcanic ash infiltration resistance since it can be formed alongside with apatite which controls or limits the amount of Y3+ available for glass crystallization. The Fe rich garnet phase containing all the possible elements exhibited a slower nucleation compared to apatite and its growth was enhanced with slow cooling rates. The implications of phase stability and heat treatment effects on the reaction products are discussed for tests performed at 1250 °C.

Effect of Water Temperature, pH Value, and Film Thickness on the Wettability Behaviour of Copper Surfaces Coated with Copper Using EB-PVD Technique

This research investigates the effect of surface roughness, water temperature, and pH value on the wettability behaviour of copper surfaces. An electron beam physical vapour deposition technique was used to fabricate 25, 50, and 75 nm thin films of copper on the surface of copper substrates. Surface topographical analysis, of the uncoated and coated samples, was performed using an atomic force microscopy device to observe the changes in surface microstructure. A goniometer device was then employed to examine the surface wettability of the samples by obtaining the static contact angle between the liquid and the attached surface using the sessile drops technique. Waters of pH 4, 7, and 9 were employed as the contact angle testing fluids at a set of fixed temperatures that ranged from 20°C to 60°C. It was found that increasing the deposited film thickness reduces the surface roughness of the as-prepared copper surfaces and thus causing the surface wettability to diverge from its initial hydrophobic nature towards the hydrophilic behaviour region. A similar divergence behaviour was seen with the rise in temperature of water of pH 4, and 9. In contrast, the water of pH 7, when tested on the uncoated surface, ceased to reach a contact angle below 90o. It is believed that the observed changes in surface wettability behaviour is directly linked to the liquid temperature, pH value, surface roughness, along with the Hofmeister effect between the water and the surface in contact.

Characterization and electrochemical behavior of ZrO2/CSZ coated 316L SS before and after incubation with calcium precipitating oral bacteria

Ceria stabilized zirconia (CSZ) and zirconia (ZrO2) were deposited by electron beam physical vapor deposition (EBPVD) technique. The tetragonal and monoclinic phases of CSZ and ZrO2 were confirmed by x-ray diffraction (XRD). Smooth surface topography with equally distributed grains was observed through atomic force microscopy (AFM) observation. Calcium carbonate/phosphate precipitation by Paenibacillus sp. oral bacteria (CPOB) was isolated and identified. Biomineralization study was carried out to determine the apatite formation behavior of the samples and the results revealed that high degree of apatite formation was occurred on coated substrates rather than bare 316 L SS samples. Further, electrochemical corrosion analysis was conducted in presence and absence of oral bacteria. The results revealed that the samples containing bacteria showed improved corrosion resistance behavior due to the formation of calcite precipitation.

Room temperature electrical spin injection from a new spin gapless ferromagnetic semiconducting inverse Heusler alloy Mn2CoSi into p-Si via SiO2 tunnel barrier

Inverse Heusler alloys possessing spin gapless semiconducting behavior have drawn great curiosity among researchers in the past few months on account of their unique transport characteristics that can be put into use in spin based electronic device implementations. Thin films of a possible ternary spin gapless semiconductor Mn2CoSi (MCS) inverse Heusler alloy have been deposited on a p-Si (100) substrate using the electron beam physical vapor deposition technique. The as-grown films exhibit a polycrystalline nature having a uniform and smooth surface with full coverage. A magnetic study reveals that the film is ferromagnetically soft along the direction parallel to its plane and its Curie temperature (TC) is much higher than room temperature (300 K). The formation of the MCS/SiO2/p-Si heterostructure is confirmed from cross-sectional transmission electron microscopy and cross-sectional scanning electron microscopy studies. The electronic- and magneto-transport properties of the heterostructure have been studied at various isothermal conditions. From current–voltage characteristics, a conventional magnetic diode like behavior has been observed throughout the working temperature regime of 78–300 K. The temperature coefficient of resistance (TCR) value of the film is estimated to be –2.09 × 10−9 Ω m/K, which is similar to the TCR values of reported spin gapless semiconductors. Room temperature spin injection and detection in a nonmagnetic semiconductor (p-Si) has been carried out using the three-terminal Hanle device in our MCS/SiO2/p-Si heterostructure. The estimated values of spin lifetime (78 ps) and spin diffusion length (167 nm) of the injected carriers at room temperature provide an indication of their industrial importance in future spin based electronic device applications.

Silver-ceria stabilized zirconia composite coatings on titanium for potential implant applications

Surface tailoring of titanium (Ti) implant is an effective way to prevent the initial bacterial adhesion and to improve the biocompatibility of the implants. In view of that, single layered silver (Ag)-ceria stabilized zirconia (CeSZ) nanocomposite coatings were developed on titanium substrates by co-evaporation method using electron beam physical vapor deposition (EBPVD) technique. The concentration of silver was varied from 0, 5 and 10 weight percentage and their microstructure, morphology, bacterial adhesion and corrosion properties were analyzed. Silver-ceria stabilized zirconia nanocomposite coatings have shown superior corrosion resistance than uncoated Ti substrate. Antibacterial efficiency of the coated and uncoated Ti substrates were evaluated using E. coli bacterial strain. Cytotoxic behavior of silver doped and undoped CeSZ coating was carried out in 3T3 mouse fibroblast cells. Electrochemical impedance spectroscopy (EIS) analysis indicated that higher corrosion resistance was observed in 5 wt% Ag added CeSZ nanocomposite coating system than other coated and uncoated substrates.

GMR Based Spin Valve like Magnetic Diode Exploiting Negative JMR in Heusler Alloy Thin Film/Semiconductor Heterostructures

Room temperature spin valve like magnetic diode behavior has been found in Co2MnSi/SiO2/n-Si heterostructure. The Co2MnSi (CMS) Heusler alloy film has been grown on n type Si (001) substrate with the help of Electron Beam Physical Vapour Deposition technique. We have investigated the transport properties of our heterostructure at various isothermal conditions in the temperature regime of 78-300 K. From the current (I) – voltage (V) characteristics of the junction, excellent rectifying tunnel diode like behavior have been seen near room temperature. The current (I) across the junction has been found to be increased with the application of magnetic B-field parallel to the CMS film clearly indicating negative Junction Magnetoresistance (JMR) of the heterostructure. It has been found to be negative 80% at 300 K at a magnetic field of 0.5 Tesla. When forward dc bias is applied to the heterostructure, the I-V characteristics are greatly influenced on turning on the field B = 0.5 T at 300 K, and the current reduces to the equal order of the magnitude of the reverse bias current. Hence our CMS/SiO2/n-Si heterostructure can perform in off (Ioff)/on (Ion) states with the use of zero/nonzero magnetic field like a spin valve at room temperature (300 K).

Isothermal Oxidation Behavior of Gadolinium Zirconate (Gd2Zr2O7) Thermal Barrier Coatings (TBCs) produced by Electron Beam Physical Vapor Deposition (EB-PVD) technique

Abstract Thermal Barrier Coatings (TBCs) provide thermal insulation for gas turbine components operating at high temperatures. Generally, TBCs were produced on a MCrAlY bond coat with 7-8% Yttria Stabilized Zirconia (YSZ) using Atmospheric Plasma Spray (APS) technique. In this study, Inconel 718 substrate material was coated with CoNiCrAlY bond coat using high velocity oxygen fuel (HVOF) technique. Afterward, Gd2Zr2O7 was deposited on samples using Electron Beam Physical Vapor Deposition (EB-PVD) technique. Produced TBCs were exposed to isothermal oxidation tests at 1000°C for 8 h, 24 h, 50 h and 100 h in muffle furnace. Scanning electron microscopy-energy distribution X-ray (SEM-EDX) spectroscopy was used to investigate thermally grown oxide (TGO) layer and TGO growth behavior of TBCs. In addition, X-ray Diffractometer (XRD) analysis was performed to TBCs to understand whether phase transformation occurs or not before and after oxidation.