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Metal-based materials, pivotal for industrialization and technological progress, confront the long-standing issue of high thermal expansion, which limits their application in advanced scenarios. With a century-long research history, negative thermal expansion materials, particularly those in intermetallic compounds, offer promising solutions for regulating thermal expansion. Here, we investigate polycrystalline TbCoSi[sub.2] ingots, revealing a notable 3% in-plane shrinkage from 223 K to 298 K induced by structural phase transitions. Temperature-dependent XRD and Rietveld refinement identify a low-temperature Pbcm space group structure, and the drastic a-axis shrinkage during the phase transition drives the in-plane contraction. Macroscopic magnetic measurements and first-principles calculations reveal an antiferromagnetic structure below 13.7 K, with magnetic and structural phase transitions being independent. These findings present a metal-based weakly magnetic material for precise thermal expansion control, particularly in the uniaxial direction.

Developing sustainable and clean energy‐conversion techniques is one of the strategies to simultaneously meet the global energy demand, save fossil fuels and protect the environment, in which nanocatalysts with high activity, selectivity and durability are of great importance. Intermetallic nanocrystals, featuring their ordered atomic arrangements and predictable electronic structures, have been recognized as a type of active and durable catalysts in energy‐related applications. In this minireview, the very recent progress in the syntheses and electrocatalytic applications of noble metal‐based intermetallic nanocrystals is summarized. Various synthetic strategies, including the conventional thermal annealing approach and its diverse modifications, as well as the wet‐chemical synthesis, for the construction of binary, ternary and high‐entropy intermetallic nanocrystals have been discussed with representative examples, highlighting their strengths and limitations. Then, their electrocatalytic applications toward oxygen reduction reaction, small molecule oxidation reactions, hydrogen evolution reaction, CO2/CO reduction reactions, and nitrogen reduction reaction are discussed, with the emphasis on how the ordered intermetallic structures contribute to the enhanced performance. We conclude the minireview by addressing the current challenges and opportunities of intermetallic nanocrystals in terms of syntheses and electrocatalytic applications. The very recent progress in the syntheses and electrocatalytic applications of intermetallic nanocrystals is reviewed. Various synthetic strategies, including the conventional thermal annealing and its diverse modifications and wet‐chemical synthesis, for the preparation of binary, ternary, and high‐entropy intermetallic nanocrystals are summarized. Their electrocatalytic applications toward ORR, small molecule oxidation, HER, CO2/CO reduction and nitrogen reduction reaction are discussed.

Intermetallic compounds (IMCs) growth can simultaneously bring about low-resistance electrical pathways and drastically reduce joint lifetime. Recently, incorporated trace nanoparticles into the free-Pb solder were found to promote the performance of the solder joints. Sn3Ag0.9Zn (SAZ) nano-composite solders were developed by doping 0.5 wt.% Al[sub.2]O[sub.3] nanoparticles into the SAZ solder. The IMCs formation and growth behavior at the interfacial reactions between the SAZ-0.5Al[sub.2]O[sub.3] nano-composite solder and the Cu substrate during soldering at temperatures ranging from 250 to 325 °C for 30 min were investigated. The results showed that after the addition of Al[sub.2]O[sub.3] nanoparticles into the SAZ solder, the elongated-type IMCs layer changed into a prism-type IMCs layer, and Ag[sub.3]Sn nanoparticles were absorbed on the grain surface of the interfacial Cu[sub.6]Sn[sub.5] phase, effectively suppressing the growth of the IMCs layers. The activation energies (Q) for the IMCs layers (Cu[sub.6]Sn[sub.5] + Cu[sub.3]Sn) were determined to be 36.4 and 39.1 kJ/mol for the SAZ/Cu and SAZ-Al[sub.2]O[sub.3]/Cu solders, respectively.

Hydrogen is a promising energy vector; however, its storage in solid-state materials is still an unresolved problem. Hydrogen storage on Mg-based materials is an ongoing research area. Here, five materials, Mg[sub.2](Co[sub.1/3]Fe[sub.1/3]Ni[sub.1/3]), Mg[sub.2](Cu[sub.1/3]Fe[sub.1/3]Ni[sub.1/3]), Mg[sub.2](Co[sub.1/3]Cu[sub.1/3]Fe[sub.1/3]), Mg[sub.2](Co[sub.1/3]Cu[sub.1/3]Ni[sub.1/3]), and Mg[sub.2](Co[sub.1/4]Cu[sub.1/4]Fe[sub.1/4]Ni[sub.1/4]), are reported for hydrogen storage. The hydriding and dehydriding reactions in these materials proceed via two steps. The first step is associated with the Mg/MgH[sub.2] equilibrium, while the second step is related to the simultaneous formation of mixtures of hydrided Mg-intermetallics. All of the studied materials demonstrate easy hydriding in mild conditions (15 bar, 300 °C). Mg[sub.2](Co[sub.1/3]Fe[sub.1/3]Ni[sub.1/3]) can be considered the best material among the studied series, with a hydrogen storage capacity of 3.8 wt. % and a dehydriding onset temperature of 243 °C. The presence of Cu modified the equilibrium pressure of the second hydriding step and induced partial dehydriding at 250 °C in pressure-composition isothermal testing. The presence of Fe favored the hydrogen uptake in the first hydriding reaction, from 0.5 wt. % at the material without Fe to 1.1–2.2 wt. % in the Fe materials. The elements Co, Co, Cu, and Fe demonstrated synergistic effects on hydriding/dehydriding reactions.

During project STARDUST, a systematic decade-long search for micrometeorites in Norway, over 5500 specimens were recovered. Among them, a micrometeorite labelled NMM/L2, collected from a rooftop in Oslo, Norway, revealed the presence of a previously unknown Al-Cu intermetallic alloy with Al.sub.4 Cu.sub.9 stoichiometry. This new phase has been approved by the IMA Commission on New Minerals, Nomenclature and Classification as a new mineral species with the name jonlarsenite (IMA 2024-078a). The microspherule (â¼200 µm in diameter) exhibits a scoriaceous morphology and mineralogical features consistent with micrometeorites, including the presence of olivine, oxides, Fe-Ni metal beads, and Ca-rich silicate glass. Jonlarsenite occurs as â¼2 µm grains intimately intergrown with Cu-bearing aluminum and is associated with magnesian olivine, spinel, taenite, and silicate glass. Its extraterrestrial origin is revealed by oxygen isotope compositions and chondritic bulk chemistry, similar to previously reported Al- and Cu-bearing meteoritic materials.

During project STARDUST, a systematic decade-long search for micrometeorites in Norway, over 5500 specimens were recovered. Among them, a micrometeorite labelled NMM/L2, collected from a rooftop in Oslo, Norway, revealed the presence of a previously unknown Al-Cu intermetallic alloy with Al.sub.4 Cu.sub.9 stoichiometry. This new phase has been approved by the IMA Commission on New Minerals, Nomenclature and Classification as a new mineral species with the name jonlarsenite (IMA 2024-078a). The microspherule (â¼200 µm in diameter) exhibits a scoriaceous morphology and mineralogical features consistent with micrometeorites, including the presence of olivine, oxides, Fe-Ni metal beads, and Ca-rich silicate glass. Jonlarsenite occurs as â¼2 µm grains intimately intergrown with Cu-bearing aluminum and is associated with magnesian olivine, spinel, taenite, and silicate glass. Its extraterrestrial origin is revealed by oxygen isotope compositions and chondritic bulk chemistry, similar to previously reported Al- and Cu-bearing meteoritic materials. Characterisation by electron probe microanalysis (EPMA), STEM energy-dispersive X-ray spectrometry (STEM-EDS), and HR-TEM indicated the mineral to be cubic, space group P-43m, with aâ8.70 à and a calculated density of 6.979 g cm.sup.-3 . The ideal chemical formula is Al.sub.4 Cu.sub.9, with minor Fe substituting for both Al and Cu. Selected area electron diffraction (SAED) and high-angle annular dark-field scanning TEM (HAADF-STEM) imaging showed a perfect match with the known ordered structure of synthetic γ-Al.sub.4 Cu.sub.9 . Due to micrometre-scale grain size, physical properties could not be measured. Jonlarsenite expands the suite of known natural intermetallic Al-Cu(-Fe) phases and highlights the significance of micrometeorites as repositories of exotic materials formed under extreme astrophysical conditions.

The application of intermetallic compounds for understanding in heterogeneous catalysis developed in an excellent way during the last decade. This review provides an overview of concepts and developments revealing the potential of intermetallic compounds in fundamental as well as applied catalysis research. Intermetallic compounds may be considered as platform materials to address current and future catalytic challenges, e.g. in respect to the energy transition.

One class of maraging steels are strengthened by a combination of [beta]-NiAl and [eta]-Ni.sub.3Ti intermetallic phases which are precipitated during an aging heat treatment. To establish a meaningful structure-property relationship the precipitation strengthening effect from each phase must be isolated from the other strengthening mechanisms. To achieve this, a series of model alloys based on the Fe-12Ni alloy system were aged and characterized to determine the precipitation strengthening effect. In the course of this study, using a new approach, atom probe tomography was used to determine the spacing between precipitates and to calculate the individual strength contribution of the [beta] and the [eta] phase using a model describing the precipitate-dislocation interactions. It was found that the precipitation strengthening of the combined [beta] and [eta] phases is close to 1000 MPa and that the relative strengthening effect of each phase is sensitive to the Ti and Al concentration.

Cu.sub.6Sn.sub.5 intermetallic compound (IMC), which occupies most even full of solder joints bringing by the reduced size of interconnection and the multi-functional demand for devices, is a critical component contributing to the reliability of the electronic products. In this study, the orientation transformation of the cold end Cu.sub.6Sn.sub.5 grains in Cu/Sn-xAg/Cu micro solder joints under temperature gradient (TG) was investigated. It was found that the orientation transformation of the Cu.sub.6Sn.sub.5 grains significantly depended on the Ag content. With increasing Ag addition, the cold end Cu.sub.6Sn.sub.5 grains transformed from strong texture with [0001]//RD(TG) to weak texture with low Ag addition or no texture with high Ag addition. The results revealed that the Ag solid solution into the Cu.sub.6Sn.sub.5 phase and the Ag.sub.3Sn absorbates on the Cu.sub.6Sn.sub.5 grain surface or at the grain boundary contributed to the above orientation transformation. The combined effect of the Ag solid solution and Ag.sub.3Sn absorbates on orientation transformation was discussed from the viewpoints of the nucleation, growth and merging of Cu.sub.6Sn.sub.5 grains, which can provide guidelines for improving the reliability of micro joints for 3D packaging or high temperature applications.

Synchrotron radiation X-ray imaging technique was applied for in situ observation of Cu[sub.6]Sn[sub.5] intermetallic compounds (IMC) growth in Sn/Cu and Sn-3.5Ag/Cu joints under isothermal temperature conditions of 250/300/350 °C and time duration of 1.5 h. The IMC in Sn-Ag solder was characterized by the formation of grooves during the interfacial reaction, and this can be attributed to the Ag content. Kinetically, the growth rate constants for the height of Cu[sub.6]Sn[sub.5] were observed to increase with temperatures and the presence of Ag in solder. As compared to pure Sn solders, the Sn-3.5Ag solders were observed with interfacial IMC of greater height, smaller base width, and lowered aspect ratio.