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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Solubility of hydrogen in metals and its effect of pore-formation and embrittlement

The effect of alloying elements on hydrogen solubility were determined by evaluating solubility equations and interaction coefficients. The solubility of dry hydrogen at one atmosphere was investigated in liquid aluminum, Al-Ti, Al-Si, Al-Fe, liquid gold, Au-Cu, and Au-Pd. The design of rapid heating and high pressure casting furnaces used in meta foam experiments is discussed as well as the mechanism of precipitation of pores in melts, and the effect of hydrogen on the shrinkage porosity of Al-Cu and Al-Si alloys. Hydrogen embrittlement in iron base alloys is also examined.

Shahani, H. R.↗
DOE OSTI2020

Synthesis and Characterization of Pd-based Nanomaterials

Bimetallic nanoparticles (BNPs) consist of two different types of metals or alloys that are bonded together. Unique properties such as optical, electronic, thermal, and catalytic effects differ for each type of BNP. Important BNPs range from Au-Pd, Ag- Pt, Au-Pt, and Ag-Ni. Pd bimetallic nanoparticles are of interest due to their many applications such as catalysis and sensing. Bimetallic catalysts have increase reaction rates and have improved catalyst stability through the geometry and ligand distribution. Pd nanoparticles are considered to be a strong catalyst due to their high activity at low temperatures and high tolerance to moisture. The catalytic properties of bimetallic nanoparticles depend on the structural properties such as size and shape. Core-shell, hollow structure, and multi-shell alloy are three possible structures nanoparticles can form as bimetallic catalysts. BNPs can be synthesized through different methods to control the size, shape, and structure. To obtain different morphologies, a variety of methods can be performed. Different methods can range from the usage of the glancing angle deposition (GLAD) to the galvanic replacement reaction, but the methods all depend on the properties of the metals. The galvanic displacement reaction was the method used to obtain Pd-based nanoparticles. This reaction is best know for obtaining hollow shaped NPs. To determine what redox process was preformed, the activity series of metals was used. From the activity series of metals, silver (Ag) was selected to preform Pd-based nanoparticles. Objectives: Synthesize Ag nanoparticles and Ag-Pd nanoparticles to understand the morphology. Characterize the synthesized nanoparticles using scanning electron microscopy (SEM), phase analysis light scattering (PALS), dynamic light scattering (DLS), energy dispersive X-ray spectroscopy (EDS), and UV-Vis spectroscopy. Results: In the UV-Vis spectrum, the Ag-Pd bimetallic NP's plasmon band decreased as the volume of palladium increased. The surface charge increases as the concentration of palladium increases. The Pd{sup 2+} ions interact with the sodium citrate surface, and decrease the negative charge. Conclusion: Ag-Pd nanoparticles were successfully created and stabilized with sodium citrate. The addition of Pd decreased the prominent plasmon band of the Ag nanoparticles. The SEM analysis showed that Ag nanoparticles had a well-defined structure, while the Ag-Pd nanoparticles showed hollow and rough structure. The EDX analysis confirmed the presence of silver and palladium. This material can be used in many industrial and research fields such as organic synthesis, fuel cells, and environmental sensing and remediation.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Materials Data on PdAu3 by Materials Project

PdAu3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pd is bonded to twelve equivalent Au atoms to form PdAu12 cuboctahedra that share corners with twelve equivalent PdAu12 cuboctahedra, edges with twenty-four equivalent AuPd4Au8 cuboctahedra, faces with six equivalent PdAu12 cuboctahedra, and faces with twelve equivalent AuPd4Au8 cuboctahedra. All Pd–Au bond lengths are 2.91 Å. Au is bonded to four equivalent Pd and eight equivalent Au atoms to form AuPd4Au8 cuboctahedra that share corners with twelve equivalent AuPd4Au8 cuboctahedra, edges with eight equivalent PdAu12 cuboctahedra, edges with sixteen equivalent AuPd4Au8 cuboctahedra, faces with four equivalent PdAu12 cuboctahedra, and faces with fourteen equivalent AuPd4Au8 cuboctahedra. All Au–Au bond lengths are 2.91 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PdAu3 by Materials Project

PdAu3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Pd is bonded to twelve Au atoms to form PdAu12 cuboctahedra that share corners with four equivalent PdAu12 cuboctahedra, corners with eight equivalent AuPd4Au8 cuboctahedra, edges with eight equivalent PdAu12 cuboctahedra, edges with sixteen equivalent AuPd4Au8 cuboctahedra, faces with four equivalent PdAu12 cuboctahedra, and faces with fourteen AuPd4Au8 cuboctahedra. There are eight shorter (2.91 Å) and four longer (2.93 Å) Pd–Au bond lengths. There are two inequivalent Au sites. In the first Au site, Au is bonded to four equivalent Pd and eight Au atoms to form distorted AuPd4Au8 cuboctahedra that share corners with twelve equivalent AuPd4Au8 cuboctahedra, edges with eight equivalent PdAu12 cuboctahedra, edges with sixteen AuPd4Au8 cuboctahedra, faces with four equivalent PdAu12 cuboctahedra, and faces with fourteen AuPd4Au8 cuboctahedra. There are four shorter (2.91 Å) and four longer (2.93 Å) Au–Au bond lengths. In the second Au site, Au is bonded to four equivalent Pd and eight equivalent Au atoms to form AuPd4Au8 cuboctahedra that share corners with four equivalent AuPd4Au8 cuboctahedra, corners with eight equivalent PdAu12 cuboctahedra, edges with twenty-four AuPd4Au8 cuboctahedra, faces with six equivalent PdAu12 cuboctahedra, and faces with twelve AuPd4Au8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pd3Au by Materials Project

Pd3Au is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pd is bonded to eight equivalent Pd and four equivalent Au atoms to form PdPd8Au4 cuboctahedra that share corners with twelve equivalent PdPd8Au4 cuboctahedra, edges with eight equivalent AuPd12 cuboctahedra, edges with sixteen equivalent PdPd8Au4 cuboctahedra, faces with four equivalent AuPd12 cuboctahedra, and faces with fourteen equivalent PdPd8Au4 cuboctahedra. All Pd–Pd bond lengths are 2.83 Å. All Pd–Au bond lengths are 2.83 Å. Au is bonded to twelve equivalent Pd atoms to form AuPd12 cuboctahedra that share corners with twelve equivalent AuPd12 cuboctahedra, edges with twenty-four equivalent PdPd8Au4 cuboctahedra, faces with six equivalent AuPd12 cuboctahedra, and faces with twelve equivalent PdPd8Au4 cuboctahedra.

36 MATERIALS SCIENCE↗