Title’s a bit over the top for how stupid simple my experiment was, but something really surprising happened when I added Magnesium to molten Lead, and then Molten Tin.
I made these brittle binary alloy/intermetallic compounds of various low melting point metals. I didn’t measure the weights and percentages, I just eyed things out. A roughly 50/50 (by volume, not weight) is what I was aiming for. Magnesium was the metal that was added to all molten metals (Al,Zn,Sn,Pb,) Regarding exact alloy percentages, it’s unknown to me. Addition of Mg would create a massive amount of slag that had a tendency to catch fire if kept molten for too long, and I would only get a fraction of what I put in, out. All alloys were brittle and seemingly useless regarding mechanical strength. They all looked fairly similar to one and other, but the Pb/Mg rapidly became darker and darker over an hour or so. I came back to it a few hours later and it was broken into pieces, honestly wasn’t sure if I dropped it, but it caught me off guard to see it fractured like that. But then, over the course of a few days, the ingot continued to fracture into smaller and smaller pieces! Now there was black dust piling up around what was left of the ingot. The more days went by, the finer the powder, until my little ingot was just a pile of black sand. Kinda freaked me out because I just made something that turns into lead (and magnesium) dust, so not wanting to poison myself, I threw it away. Now listen to this. About one month later, the magnesium/tin alloy started to do the same thing! The “spontaneous powderizing process” was happening again, but at a significantly slower rate. Besides the different timescale that this was occurring at, the Sn/Mg took on this vibrant metallic purple/violet color, imagine pink Silicon. Very different compared to the almost black Pb/Mg I have no idea what happened, I can easily recreate this, but I haven’t done it since. I just wanted to share this bizzare experiment.
TL;DR metal Ingot spontaneously shattered over, and over again, until it was dust
Identifying novel classes of precatalysts for the oxygen evolution reaction (OER by water oxidation) with enhanced catalytic activity and stability is a part of key strategies to enable chemical energy conversion. The vast chemical space of intermetallic phases offers plenty of opportunities to discover OER electrocatalysts with improved performance. Here we report intermetallic nickel germanide (NiGe) acting as a superiorly active and durable Ni‐based electro(pre)catalysts for OER produced from a molecular bis(germylene )‐ Ni precursor. The ultra‐small NiGe nanocrystals deposited on both nickel foam and fluorinated tin oxide (FTO) electrodes show lower overpotentials and a durability of over three weeks (505 h) in comparison to the state‐of‐the‐art Ni‐, Co‐, Fe‐, and benchmark NiFe‐based electrocatalysts under identical alkaline OER conditions. In contrast to other Ni‐based intermetallic precatalysts under alkaline OER conditions, an unexpected electroconversion of NiGe into g ‐Ni III OOH with intercalated OH ‐ /CO 3 2‐ transpired that served as a highly active structure as shown by various ex‐situ methods and quasi in‐situ Raman spectroscopy .
We unravel a structural feature that has remained unsolved for decades. An incommensurate occupational modulation creates a particular nanoscale ordering of MnAs and NiAs layers in the intermetallic Mn0.60Ni0.40As solid solution phase. We have investigated this phenomenon by 3D electron diffraction (PEDT), high‐angle annular dark‐field (HAADF) imaging, and neutron diffraction.
In this work we benefited from recent advances in tools for crystal‐structure analysis that enabled us to describe an exotic nanoscale phenomenon in structural chemistry. The Mn0.60Ni0.40As sample of the Mn1−x Ni x As solid solution, exhibits an incommensurate compositional modulation intimately coupled with positional modulations. The average structure is of the simple NiAs type, but in contrast to a normal solid solution, we observe that manganese and nickel segregate periodically at the nano‐level into ordered MnAs and NiAs layers with thickness of 2–4 face‐shared octahedra. The detailed description was obtained by combination of 3D electron diffraction, scanning transmission electron microscopy, and neutron diffraction. The distribution of the manganese and nickel layers is perfectly described by a modulation vector q=0.360(3) c*. Displacive modulations are observed for all elements as a consequence of the occupational modulation, and as a means to achieve acceptable Ni–As and Mn–As distances. This modulated evolution of magnetic MnAs and non‐magnetic NiAs‐layers with periodicity at approximately 10 Å level, may provide an avenue for spintronics.
Does anyone know what happened to Crystmet, the metals structure database? The website seems to have disappeared.
Is there any way to access the database or is there a recommended powder diffraction database for metals/alloys/intermetallics that goes beyond PDF or ICDD? I would like to have access to CIF files for relatively uncommon non-stoichiometric intermetallics.
Journal of the American Chemical SocietyDOI: 10.1021/jacs.0c01716
Pd‐Ni‐Pt in the mix: A method for studying the intermixing process in a shaped nanoparticle was devised. It uses multilayered Pd‐Ni‐Pt core–shell nanocubes as precursors. Under mild conditions, the intermixing between Ni and Pt could be tuned by changing layer thickness and number, triggering intermixing while preserving nanoparticle shape.
Controlling the surface composition of shaped bimetallic nanoparticles could offer precise tunability of geometric and electronic surface structure for new nanocatalysts. To achieve this goal, a platform for studying the intermixing process in a shaped nanoparticle was designed, using multilayered Pd‐Ni‐Pt core–shell nanocubes as precursors. Under mild conditions, the intermixing between Ni and Pt could be tuned by changing layer thickness and number, triggering intermixing while preserving nanoparticle shape. Intermixing of the two metals is monitored using transmission electron microscopy. The surface structure evolution is characterized using electrochemical methanol oxidation. DFT calculations suggest that the low‐temperature mixing is enhanced by shorter diffusion lengths and strain introduced by the layered structure. The platform and insights presented are an advance toward the realization of shape‐controlled multimetallic nanoparticles tailored to each potential application.
Journal of the American Chemical SocietyDOI: 10.1021/jacs.0c05140
The nature of metal–boron orbital interactions in boron‐bearing intermetallics and its influence on the surface hydrogen adsorption property and catalytic activity aredemonstrated. Several transition‐metal–boron intermetallics are predicted to be efficient hydrogen‐evolving materials with catalytic activity approaching platinum, and among them RuB is confirmed experimentally.
A theoretical and experimental study gives insights into the nature of the metal–boron electronic interaction in boron‐bearing intermetallics and its effects on surface hydrogen adsorption and hydrogen‐evolving catalytic activity. Strong hybridization between the d orbitals of transition metal (TM) and the sp orbitals of boron exists in a family of fifteen TM–boron intermatallics (TM:B=1:1), and hydrogen atoms adsorb more weakly to the metal‐terminated intermetallic surfaces than to the corresponding pure metal surfaces. This modulation of electronic structure makes several intermetallics (e.g., PdB, RuB, ReB) prospective, efficient hydrogen‐evolving materials with catalytic activity close to Pt. A general reaction pathway towards the synthesis of such TMB intermetallics is provided; a class of seven phase‐pure TMB intermetallics, containing V, Nb, Ta, Cr, Mo, W, and Ru, are thus synthesized. RuB is a high‐performing, non‐platinum electrocatalyst for the hydrogen evolution reaction.
Journal of the American Chemical SocietyDOI: 10.1021/jacs.9b13313
A novel and general strategy for the synthesis of reduced graphene oxide (rGO) supported atomically ordered Pt3M (M=Mn, Cr, Fe, Co, etc.) intermetallic nanoparticles is reported under the aid of freeze‐drying technology. This synthetic strategy is demonstrated to be effective for the preparation and handling of nanoparticles with controlled particle size and ordered phase.
Controllable synthesis of atomically ordered intermetallic nanoparticles (NPs) is crucial to obtain superior electrocatalytic performance for fuel cell reactions, but still remains arduous. Herein, we demonstrate a novel and general hydrogel‐freeze drying strategy for the synthesis of reduced graphene oxide (rGO) supported Pt3M (M=Mn, Cr, Fe, Co, etc.) intermetallic NPs (Pt3M/rGO‐HF) with ultrasmall particle size (about 3 nm) and dramatic monodispersity. The formation of hydrogel prevents the aggregation of graphene oxide and significantly promotes their excellent dispersion, while a freeze‐drying can retain the hydrogel derived three‐dimensionally (3D) porous structure and immobilize the metal precursors with defined atomic ratio on GO support during solvent sublimation, which is not afforded by traditional oven drying. The subsequent annealing process produces rGO supported ultrasmall ordered Pt3M intermetallic NPs (≈3 nm) due to confinement effect of 3D porous structure. Such Pt3M intermetallic NPs exhibit the smallest particle size among the reported ordered Pt‐based intermetallic catalysts. A detailed study of the synthesis of ordered intermetallic Pt3Mn/rGO catalyst is provided as an example of a generally applicable method. This study provides an economical and scalable route for the controlled synthesis of Pt‐based intermetallic catalysts, which can pave a way for the commercialization of fuel cell technologies.
CO 2 methanation exhibits great potentials in environmental remediation and renewable energy storage. Therefore, it is of pivotal importance to develop efficient catalysts and investigate the intrinsic mechanism for CO 2 methanation. Herein, we reported that PdFe intermetallic nanocrystals afforded high activity and stability for CO 2 methanation. The mass activity of fct ‐PdFe nanocrystals reached 5.3 mmol g ‐1 h ‐1 , under 1 bar (CO 2 :H 2 = 1:4) at 180 o C, being 6.6, 1.6, 3.3, and 5.3 times as high as that of fcc ‐PdFe nanocrystals, Ru/C, Ni/C, and Pd/C, respectively. After 20 rounds of successive reaction, 98% of the original activity was retained for PdFe intermetallic nanocrystals. Further mechanistic studies revealed that PdFe intermetallic nanocrystals enabled the maintenance of metallic Fe species via a reversible oxidation‐reduction process in CO 2 methanation. The metallic Fe in PdFe intermetallic nanocrystals induced the direct conversion of CO 2 into CO* as the intermediate, contributing to the enhanced activity.
So today I heard a talk about new methods for the productions of prototypes which are used at BMW and it was told that also 3d printing of metals is used. So now me as a chemist thought that most the time actually inter metallic phases are used for airplanes and cars(I think so?) And so I thought that they would also use those intermetallic phases for 3d printing but I think a big challenge would be to get the right phase How is it achieved to get the desired phase? Or maybe it is pretty simple but I imagine it to be quite difficult because for the 3d printing process the used material has to be a fluid for a short time,right?
Title pretty much sums it up. Feel free to use as many examples as possible. I can't think of enough to draw any conclusions. This might sound contradictory to "isn't easily oxidized," but I'm mainly interested in ferrous alloys. I suppose it's relative as far as I understand, but iron doesn't oxidize like crazy in air compared to rare earths, or alkali / alkaline earths.
Of course, I'd love to hear key terms and equations (possibly thermo?) so I can look this idea up on my own.
Tagged "engineering" for materials engineering / metallurgy graduate students or professionals.
Journal of the American Chemical SocietyDOI: 10.1021/jacs.9b13508
Controllable synthesis of atomically ordered intermetallic nanoparticles (NPs) is crucial to obtain superior electrocatalytic performance for fuel cell reactions, but still remains arduous. Herein, we demonstrate a novel and general hydrogel‐freeze drying strategy for the synthesis of reduced graphene oxide ( rGO ) supported Pt 3 M (M= Mn, Cr, Fe and Co etc.) intermetallic NPs (Pt 3 M/rGO‐HF) with ultrasmall particle‐size (about 3 nm) and dramatic monodispersity. The formation of hydrogel prevents the aggregation of graphene oxide and significantly promotes their excellent dispersion, while a freeze‐drying can retain the hydrogel derived three‐dimensionally (3D) porous structure and immobilize the metal precursors with defined atomic ratio on GO support during solvent sublimation, which is not afforded by traditional oven drying. The subsequent annealing process produces rGO supported ultra‐small ordered Pt 3 M intermetallic NPs (~3 nm) due to confinement effect of 3D porous structure. Such Pt 3 M intermetallic NPs exhibit the smallest particle size among the reported ordered Pt‐based intermetallic catalysts. A detailed study of the synthesis of ordered intermetallic Pt 3 Mn/rGO catalyst is provided as an example of a generally applicable method. This study provides an economical and scalable route for the controlled synthesis of Pt‐based intermetallic catalysts, which can pave a way for the commercialization of fuel cell technologies.