Platinum is added to thermal barrier coatings (TBCs) as it is observed empirically to extend their lifetime, but the mechanism by which Pt acts is unknown. Since Pt has been proposed to alter diffusivities in NiAl, a key component of TBCs, we use first-principles quantum mechanics calculations to investigate atomic level diffusion mechanisms. Here, we examine the effect of Pt on five previously...

The energetics of Ni vacancy jumps in the intermetallic compound NiAl are studied by combining embedded-atom and first-principles calculations. The embedded-atom potential used in this work is fit to both experimental and first-principles data and provides an accurate description of point defect energies and vacancy jump barriers in NiAl. Some of the embedded-atom results reported here, are ind...

Using the full potential linearized augmented plane wave (FLAPW) method, we have explored the magnetic properties of one dimensional (1D) Ti atomic chain. Astonishingly, we for the first time observed that the 1D Ti atomic chain has ferromagnetic ground state even on NiAl(110) surface although the Ti has no magnetic moment in bulk or macroscopic state. It was found that the physical property of...

Stacking faults in CoCrTa/Cr, CoCrPt/NiAl, and CoCrPt/Cr/NiAl films have been studied by electron diffraction. Interfacial lattice match and epitaxial growth play important roles in reducing the stacking fault density. It is found that the bicrystal media has large stacking fault densities. In the unicrystal media case, when good epitaxy between magnetic layer and underlayer cannot be achieved,...

The high-temperature oxidation of Hf-modified NiAl alloy at 950 °C results in the formation γ-Al2O3 and θ-Al2O3. Exclusive HfO2 particles is observed adherent γ-Al2O3/NiAl interface. By contrast, θ-Al2O3/NiAl interface multi-layered oxide growth consisting alternate thin thick layers θ-Al2O3 NiAl2O4 along with dispersed layers. This difference elucidated by first-principle calculations showing ...

Metals that work at high temperatures (for instance, superalloys in gas-turbines) depend on thermally grown oxide (TGO, commonly alumina) to withstand corrosion attack. Nickel Aluminide (NiAl) as one superior alumina TGO former plays an important role in protective coatings for turbine blades in gas-turbine engines used for aircraft propulsion and power generation. Lowering TGO growth rate is e...

A morphological strategy consisting of nanocasting synthesis nickel aluminate spinel precursor was addressed. Two nanocasted catalysts were synthesized involving different template-removal procedures (i.e., Teflon-assisted calcination vs. NaOH washing) for recovery. As a reference, NiAl2O4 supported by SBA-15 and bare selected. The obtained solids characterized in detail, examining their textur...

The pressure-volume-temperature equation of state of the intermetallic compound NiAl was calculated theoretically, and compared with experimental measurements. Electron ground states were calculated for NiAl in the CsCl structure, using ab initio pseudopotentials and density functional theory (DFT), and were used to predict the cold compression curve and the density of phonon states. It was des...

Mesoporous nano Ni-Al2O3 catalysts were prepared by using Pluronic P123 (P123) and fatty alcohol polyoxyethylene ether (AEO-7) as structure directing agents (SDAs), applied for CO2 methanation in a continuously stirred tank reactor (CSTR). Compared with NiAl-A AEO-7 SDA NiAl-N without SDA, NiAl-P possesses ordered mesopores, high Ni dispersion, large metal surface area amounts of adsorbed CO2, ...

Bulk metallic glasses are a relatively new class of amorphous metal alloy which possess unique mechanical and magnetic properties. The specific concentrations and combinations of alloy elements needed to prevent crystallization during melt quenching remains poorly understood. A correlation between atomic properties that can explain some of the previously identified glass forming ability (GFA) a...