High Temperature Oxidation Behavior Research Articles

High-temperature oxidation behavior of GH4169 and Inconel617 nickel-based superalloys in SOFC environment

Field exposure for 5000h combined with weight gain measurement and morphology/composition analysis of oxide film were conducted to examine high temperature oxidation behavior of GH4169 and In617 nickel-based super alloys in SOFC system environment. The In617 alloy has been found to demonstrate excellent oxidation resistance in the SOFC environment because of its high Ni content. An integral and dense NiO oxide film can be developed in the outer layer with a continuous Cr2O3 oxide film formed in inner layer. It indicates that NiO played a crucial role in the formation of an integral and dense oxide film. In contrast, GH4169 alloy failed to develop a continuous and dense oxide film probably due to high Fe content, in which case Fe-dopped chromium oxide (Fe,Cr)2O3 was formed. As a result, the oxide film was loose and porous, leading to relatively poor oxidation resistance.

Oxidation behavior and mechanical properties of a directionally solidified high Nb TiAl based alloy between 800 °C and 900 °C

The high temperature oxidation behavior and mechanical property response of a directionally solidified Ti-46Al-7Nb-0.4W-0.6Cr-0.1B alloy were investigated. The ultimate tensile strength of the alloy at 800 °C, 850 °C and 900 °C are 647 MPa, 590 MPa and 508 MPa, respectively, and the tensile fracture mode changed from brittle cleavage fracture to micro-void accumulation ductile fracture. At lower temperatures Al2O3 forms first, growing along the γ lamellae to form oxide bands aligned with the lamellar orientation. The oxidation mass gain of the alloy after 900 °C/100 h isothermal oxidation is only 0.91 mg/cm2. The oxidation kinetics results show the microalloyed high Nb TiAl alloy has excellent oxidation resistance, which is due to the formation of a TiO2 layer containing Nb, Cr and W, the AlNb2 phase and an Al/Cr rich transition layer above the directionally solidified lamellar matrix.

High-temperature oxidation behavior of GH4169 superalloy repair by wire-fed electron beam directed energy deposition

This study systematically examines the high-temperature oxidation behavior of GH4169 nickel-based superalloy repaired via wire-fed electron beam directed energy deposition (EB-DED). The analysis focuses on two distinct regions: the deposited zone and substrate zone. After exposure to 850 °C for 120 h, the oxidation films consisted of an outer layer of Cr2O3 and an inner layer of Al2O3 and TiO2. The deposition zone exhibits lower oxidation resistance, attributed to more pronounced element segregation resulting from the EB-DED process condition. This investigation establishes a clear correlation between element segregation and oxidation resistance, demonstrating that severe element segregation leads to poor oxidation resistance.

Effect of Cr content on the high temperature oxidation behavior of FeCoNiMnCrx porous high-entropy alloys

FeCoNiMnCr porous high-entropy alloys were prepared using the activation reaction sintering method with Fe, Co, Ni, Mn, and Cr as raw materials. The oxidation behaviors of FeCoNiMnCrx porous high-entropy alloys with different Cr contents, such as pore structure, the surface oxide film phase composition, structure, and morphology, were characterized by X-ray diffraction (XRD), electron probe micro analysis (EPMA), energy dispersive X-ray spectroscopy (EDS), and pore tester after high-temperature oxidation at 800–1000 °C. The results indicate that the initial porous high-entropy alloy comprises a single FCC solid solution phase. With the increase in Cr content, the average pore diameter, average porosity, and air permeability of the porous high-entropy alloy also increase. The oxidation kinetics of the porous high-entropy alloy after exposure to temperatures between 800 °C and 1000 °C follows a single-stage parabolic evolution law. At the same oxidation temperature, With the increase of Cr content, the oxidation gains gradually increased, at the same Cr content at different temperatures, the antioxidant performance of 1000 °C was the weakest, followed by 800 °C, and 900 °C showed excellent antioxidant performance. The oxidation products are mainly Mn2O3, Mn3O4, (Mn, Cr)3O4, Cr2O3and Fe2O3.

Microstructure evolution and high-temperature oxidation behavior of low-carbon MgO-C refractories with TiB2 addition

Combining the advantages of both containing-B compounds and containing-Ti compounds, a new TiB2 addition is proposed in MgO-C refractories. In this paper, the high-temperature oxidation behavior of low-carbon MgO-C refractories with TiB2 addition was investigated, especially the effect of microstructure and phase evolution on the high-temperature oxidation behavior was discussed. The results show that in the materials, TiB2 preferentially reacts with oxygen, forming TiCxN1-x, Mg3(BO3)2 and Mg2TiO4 ceramic phases, and catalyzing the decomposition of phenolic resin to form bamboo-like nanotubes and carbon nanospheres to bond aggregates and fill pores. Meanwhile, TiB2 also promotes the formation of regenerated MgO compact zone, hindering the diffusion of oxygen into the materials to improve the oxidation resistance. Compared with the blank control specimen and the specimen with B4C addition, the oxidation resistance increased by 243.4 % and 79.2 %, respectively.

Microstructure evolution and high temperature air oxidation behaviour of thick Cr coatings at 1200 °C

The thick Cr coated Zr-4 alloys were prepared by magnetron sputtering deposition and their microstructure evolution and high-temperature air oxidation behaviour were investigated. Oxidation tests showed that the thick Cr coatings can improve the high-temperature air oxidation resistance of Zr-4 alloy even if the α-Zr(O) layer was formed at some regions. The mechanism of high-temperature air oxidation was also discussed in detail, and these experimental results could provide data for establishing a reliable prediction model of this degradation.

Review on Nickel Nitride Composite Coatings

Abstract Nickel based composite coating has been widely used in many field applications such as wear and corrosion resistance since it is possible to improve its properties by depositing a variety reinforcement and process parameters. In this work, a variety of reinforced nitride particles such as TiN, AlN and Si were used to enhance the microstructure, mechanical and oxidation properties of nickel nitride composite coating in improving the coating density and surface morphology. The electrodeposition method was used to develop the composite coating with variety process parameters including temperature and current density. The coating stress was calculated from crystal structure data to investigate its involvement in the mechanical properties of coatings. The high temperature oxidation behavior of nickel nitride composite coatings was studied by heating process. The review highlights the reinforced nitride particles and process parameters improve the hardness and wear resistance of nickel based composite coating, however, the improvement also involves the coating stress. From study result of high temperature oxidation process, it obtained that the aluminum oxide remains within the coating indicating its role play in protecting substrate from corrosion. Experimental study on surface modification and microstructure of nickel based composite coating are highly expected and meet a great challenge for different applications with superior mechanical and tribological properties.

Si modified aluminide coatings on a Ni-base superalloy prepared using Al-Si plasma irradiation: Growth mechanism and oxidation behavior

The growth mechanism and high temperature oxidation behavior of Si-modified aluminide coatings prepared on a Ni-base single crystal superalloy DD98M using vacuum plasma irradiation were investigated. The growth of the coatings under plasma irradiation was much faster than thermal diffusion-controlled process. The coatings comprised an aluminide outer zone, where Si existed as solid-solute, and an inter-diffusion zone where silicide particles precipitated in aluminide matrix. The crystalline structures of the aluminides were found dependent on the irradiation power. β-NiAl was formed at higher irradiation power while δ-Ni2Al3 was formed at lower irradiation power. The β-NiAl coatings had higher oxidation resistance than the δ-Ni2Al3 ones usually, with an exception of one β coating which was prepared at the highest substrate bias which underwent severe internal oxidation. The presence of numerous voids in the oxide scale of Ni2Al3 may be related to the large number of Kirkendall voids present in the as-prepared coating.

Oxidation behavior and failure mechanisms of enamel coatings at different temperature

This work studies the prolonged high-temperature oxidation behavior and failure mechanisms of enamel coatings at three distinct temperatures: 600°C, 800°C, and 1000°C. The evolution of the coating’s microstructural morphology was characterized, and the kinematics of porosity, crystal precipitation, and oxide layer thickness were measured. The results indicated that at 600°C and 800°C, the coatings exhibit strong oxidation resistance and retain their mechanical integrity. However, at 1000°C, the coatings rapidly deteriorate due to formation of Cr microcrystalline bands and the diffusion of oxidation layer, leading to volume expansion and element segregation. These factors result in the formation of voids and stress concentrations. The precipitation of crystals further exacerbates localized stress and microcracks, increasing the brittleness and enlarging the stress concentration areas, ultimately causing coating spallation. The effects of cooling rate on the long-term oxidation lifetime of the coatings were also examined. The findings of this work suggest that the temperatures below 800°C are suitable for long-term application of the enamel coatings, while exposure to 1000°C results in their rapid failure.

Oxidation behavior of an ultra-high strength and ductile Ni-enriched complex concentrated alloy

Recent research work revealed that Ni43.9Co22.4Fe8.8Al10.7Ti11.7B2.5 HEA is one of the ultra-high strength and ductile superlattice alloys. In this work, high-temperature oxidation behavior of the as-cast Ni43.9Co22.4Fe8.8Al10.7Ti11.7B2.5 alloy was investigated at 1000 ℃ up to 100 h. The oxidized samples were characterized using X-ray Diffractometer, Energy Dispersive Spectroscopy, and X-ray Photoelectron Spectroscopy. The results revealed that the initial microstructure of the alloy consists of face centered cubic (FCC) and L12 structures. High-temperature exposure resulted in the formation of Al2O3 and TiO2 scales during the initial hours of oxidation, which eventually spall-off after 25 h of exposure allowing further oxidation. The results showed that protective oxide layers such as Al2O3 and TiO2 were not present after 100 h of exposure. The external layer of the 100 h oxidized sample was composed of Fe, Co, and Ni-rich oxides which are known to have mere effective resistance against oxygen ingression. The alloy which has superior strength and ductility may be used for high temperature applications after attaining the thermally stable fine-grain microstructure by suitable thermomechanical processing / providing oxidation resistance coating / by doping with elements having superior oxidation resistance.

Enhanced high temperature mechanical and oxidation behavior of direct energy deposited TiC/Inconel 718 gradient coatings

While Inconel 718 is commonly employed in high-temperature settings, its performance at elevated temperatures is notably diminished in comparison to its performance under ambient conditions. In this study, Inconel 718 (IN718), Inconel 718 with 5 layer of Inconel 718–5 wt% TiC gradient coatings (CG-5), and Inconel 718 with 5 layer of Inconel 718–10 wt% TiC gradient coatings (CG-10) were fabricated using direct energy deposition (DED) to investigate the influence of TiC content on the mechanical and oxidation properties at elevated temperatures through the regulation of microstructural changes. Following the incorporation of TiC, the microstructures underwent a transformation into refined equiaxed crystals, carbides, and columnar crystals, replacing the coarsened columnar crystals and Laves phase present in IN718. Compared to IN718, the high-temperature tensile strength of CG-5 and CG-10 has increased by 80% and 180% at 900 ℃. Meanwhile, the mass gain due to oxidation per unit area of CG-5 and CG-10 has decreased by 23% and 11%, respectively. The results indicate that CG-10 exhibits a combination of highest high-temperature tensile strength and the enhanced resistance to high-temperature oxidation when compared to IN718 and CG-5.

Influence of temperature, oxygen partial pressure, and microstructure on the high-temperature oxidation behavior of the SiC Layer of TRISO particles

Tristructural isotropic (TRISO)-coated fuel particles are designed for use in high-temperature gas-cooled nuclear reactors, featuring a structural SiC layer that may be exposed to oxygen-rich environments over 1000 °C. Surrogate TRISO particles were tested in 0.2–20 kPa O2 atmospheres to observe the differences in oxidation behavior. Oxide growth mechanisms remained consistent from 1200–1600 °C for each PO2, with activation energies of 228 ± 7 kJ/mol for 20 kPa O2 and 188 ± 8 kJ/mol for 0.2 kPa O2. At 1600 °C, kinetic analysis revealed a change in oxide growth mechanisms between 0.2 and 6 kPa O2. In 0.2 kPa O2, oxidation produced raised oxide nodules on pockets with nanocrystalline SiC. Oxidation mechanisms were determined using Atom probe tomography. Active SiC oxidation occurred in C-rich grain boundaries with low PO2, leading to SiO2 buildup in porous nodules. This phenomenon was not observed at any temperature in 20 kPa O2 environments.

High-temperature oxidation behaviour of additively manufactured and wrought HAYNES 282

Direct Metal Laser Sintered Haynes 282 specimens as well as wrought ones were subjected to high-temperature exposure at 1000 °C for 100h in air to compare their oxidation behaviour. The specimens were removed from the furnace after 1h, 5h, 25h, 50h and 100h to reveal and study oxidation mechanisms through morphological and cross-sectional examination by using scanning electron microscopy with energy dispersive spectroscopy attachment and X-ray diffraction. Microstructural studies revealed that the oxidation kinetics, determined by changes in thickness scale and depth of aluminium diffusion zone, were mainly driven by the formation of Cr2O3 for the wrought material, and TiO2 for DMLS one. The wrought material was characterized by the oxidation rate equal to 0.96 and followed the logarithmic law. On the other hand, DMLS-manufactured Haynes 282 exhibited oxidation rate of 0.90 and follows the linear law for the thickness scale considerations. However, when the depth of aluminium diffusion was investigated, it had an oxidation rate of 0.87 and followed cubic law.

High-temperature oxidation behavior and mechanical properties of PS-PVD sprayed Yb2Si2O7 environmental barrier coatings

The high-temperature oxidation behavior and mechanical properties of the Yb2Si2O7/Si environmental barrier coatings (EBCs) prepared by plasma spray-physical vapor deposition at 1250 °C and 1350 °C were investigated, and obvious delamination was observed after oxidation for 4000 h. The results showed that element diffusion occurred during oxidation, and the diffusion of oxygen led to the formation of thermal growth oxides (TGO), which induced pores and microcracks. The TGO played a role in hindering element diffusion, but the mismatching coefficients of thermal expansion and phase transition caused vertical and transverse cracks in the TGO layer. These cracks became channels for oxygen diffusion and ultimately resulted in delamination between TGO and the bonding coating (BC) layer. Furthermore, temperature significantly affects the oxidation kinetics of EBCs, and the oxidation within the BC layer alters its elastic modulus. The elastic modulus of the BC layer first increased and then decreased. The oxidation damage was more pronounced at 1350 °C.

Oxidation behavior and oxidation kinetics of film cooling holes at different inclination angles of a Ni-based single-crystal blade

This paper examines the high-temperature oxidation behavior of Ni-based single-crystal turbine blade film cooling holes with varying inclination angles. Utilizing the theory of oxidation kinetics, the concept of an angle influence factor is introduced, and a novel oxidation kinetic equation is formulated. This allows for precise prediction of the oxide/γ′-free layer thickness in film cooling holes across different inclination angles throughout the oxidation process. It offers a new benchmark for future lifespan prediction models, significantly impacting the assessment of the operational life of air-cooled single crystal blades.

The oxidation resistance of Ni nanoparticle incorporated SiOC coating for TiAl alloy

In this work, SiOC coatings incorporated with Ni nanoparticles were fabricated on γ-TiAl alloy by dip-coating. The microstructure and high temperature oxidation behavior of the SiOC-Ni coatings with different Ni contents were investigated. Results showed that the incorporation of Ni nanoparticles improved the oxidation resistance of the SiOC coating at 850 ℃. During thermal exposure to air, the incorporated Ni particles would react with both oxygen and the SiOC coating, forming NiO and Ni2Si, respectively, therefore changing the structure of the SiOC coating. The generation of NiO and Ni2Si is beneficial in reducing the oxygen partial pressure at the coating/substrate interface, thereby facilitating the formation of a protective aluminum oxide layer.

Comparison of high temperature oxidation behaviour of high speed steel and Hi-Cr steel

Abstract High speed steel and Hi-Cr steel are widely used as one of the important materials for rolls. The oxide layer during rolling plays a key role in the service life of the rolls and the quality of the rolled material. Therefore, it is very important to study the oxidation behaviour of high speed steel and Hi-Cr steel. In this paper, the oxidation behaviour of HSS and Hi-Cr steel is compared in the range of 500-700°C. The oxidation kinetic curve of HSS is dominated by a parabolic law, while the oxidation kinetic curve of Hi-Cr steel is dominated by a logarithmic law. To analyse the effect of their oxidation products on the oxidation behaviour, V2O5 in high speed steel plays a destructive role in the oxide layer, while Cr2O3 in Hi-Cr steel can effectively reduce the thickness of the oxide layer.

High-temperature oxidation behavior of multi-phase ceramic particles-reinforced TiAl composites with different microstructures

The high-temperature oxidation behaviors of multiphase ceramic particle-reinforced TiAl composites with different microstructures were investigated. The TiAl composites were prepared via spark plasma sintering by introducing 0.5 wt % graphene oxide and 0.3 wt% SiC into Ti-48Al-2Nb-2Cr. The near-γ equiaxed microstructure, dual-phase microstructure, and nearly fully lamellar microstructure were obtained by sintering at 1200, 1250, and 1300 °C, respectively. Moreover, multiphase ceramic particles were uniformly distributed in the TiAl matrix. Cyclic oxidation was conducted at 950 °C in air for 100 h. The TiAl composite with the nearly fully lamellar microstructure exhibited the best oxidation resistance (mass gain of 1.83 mg/cm2) and that with the near-γ microstructure exhibited the worst oxidation resistance (2.47 mg/cm2). The superior oxidation resistance of the TiAl composite with the nearly fully lamellar microstructure is attributed to the uniform distributions of Ti2AlC particles at the α2/γ lamellae interfaces and Ti5Si3 particles at the lamellae colony boundaries, which hinder atomic diffusion. Moreover, the α2/γ lamellae colonies facilitate the formation of Nb-rich and Cr-rich phases at the interface of the oxide layer and substrate, which act as a protective barrier against atomic diffusion.

High-temperature oxidation behavior of a novel γ′-strengthened superalloy manufactured by laser-beam powder bed fusion: Effect of post-heat treatment

This study systematically researched the high-temperature oxidation behavior of a γ′-strengthened alloy based on Haynes 230 prepared by laser-beam powder bed fusion (PBF-LB). The results indicate that the experimental alloy showed a higher oxidation resistance than Haynes 230 at 1000 °C. The oxidation products mainly consisted of the outmost MnCr2O4-TiO2 layer, intermediate Cr2O3 layer and inner TiO2 layer. Branched Al2O3 oxides were formed in the interior oxidation zone. Post-heat treatment can increase oxidation resistance by reducing the oxidation rates from 0.0152 mg2cm−4h−1 to 0.0126 mg2cm−4h−1. The decrease in dislocation density and the precipitation of ordered γ' phases can slow down the short-circuit diffusion and lattice diffusion rate of oxygen, and are the main reasons for this improvement. Furthermore, the γ' phase precipitation and dislocation density reduction can provide more sites for Cr2O3 nucleation and reduce the Cr supply required for grain growth. As a result, the Cr2O3 grains on the heat-treated sample surface were smaller.

On the Development of Equiaxed Microstructures in High-Entropy Superalloys and Their Impact on High-Temperature Oxidation Behavior

On the Development of Equiaxed Microstructures in High-Entropy Superalloys and Their Impact on High-Temperature Oxidation Behavior