Structure Of Intermetallic Compounds Research Articles

Multiphase Al-Zr-Fe alloys with intermetallic compound structure: Mechanisms of corrosion in 3.5 % NaCl and H3BO3 aqueous solutions

In this study, the structure of Al65Zr20Fe15 and Al71Zr24Fe5 alloys was studied using neutron diffraction and SEM with EDX maps. This paper presents the electrochemical measurement results performed in 3.5 % NaCl, H3BO3, and 3.5 % NaCl+H3BO3 solutions at 40 °C. The Al71Zr24Fe5 alloy showed higher corrosion resistance in acidic solution, whereas the Al65Zr20Fe15 alloy was more resistant in 3.5 % NaCl+H3BO3. Moreover, the corrosion behavior was described for the samples immersed for 8 weeks in 3.5 % NaCl at 40 °C. SKPFM indicated high Volta potential differences between Al-Zr and Al-Fe-Zr phases. Moreover, the higher wear resistance for Al65Zr20Fe15 compared to the Al71Zr24Fe5 alloy was demonstrated.

The Geometric and Electronic Effects of Ceria on Promoting PdZn catalyst for Enhanced Acetylene Semi‐Hydrogenation

AbstractPdZn intermetallic compounds (IMCs) have been extensively reported for acetylene semi‐hydrogenation due to unique geometric and electronic structure of isolated Pd sites. However, to achieve high ethylene selectivity at high conversion remains challenging. Here we show the promotional role of ceria in modifying the geometric and electronic structure of PdZn IMCs towards enhanced catalytic performance for acetylene semi‐hydrogenation. The Ce (0.1 wt%) promoted Pd−Zn‐Al catalyst shows by far the best catalytic performance among other Pd based catalysts in literature, maintaining high selectivity (>95 %) and excellent stability (~130 h) at high acetylene conversion (~90 %). Using in situ spectroscopic techniques, the geometric and electronic effects of CeOx promotor were clearly elucidated. At low Ce content, the presence of highly dispersed Ce3+ species in the periphery of PdZn alloys enhanced electronic metal‐oxide interaction, resulting in electron‐rich Pd sites that promote hydrogen dissociation and ethylene desorption, and account for the outstanding catalytic performance. At high Ce content, the formation of bulk‐phase CeO2 suppressed the PdHx formation during PdZn alloying and led to phase separation yielding highly dispersed Pd ensembles, consequently lowering ethylene selectivity. Our results provide a new route for the design of PdZn catalyst by applying rare earth promoters towards high‐performance acetylene semi‐hydrogenation.

Facile synthesis of Cu-Sn nanoparticle film and its bonding mechanism for power electronic packaging

The Cu-Sn full intermetallic compound is a promising high-temperature electronic packaging material, while its preparation is usually time-consuming. In this work, a novel dual-beam laser co-deposition method was proposed to prepare Cu-Sn nanoparticle film for power electronic packaging with high bonding efficiency. Various Cu-Sn contents were prepared to reveal the bonding mechanism of the full intermetallic compound structure. The results show that joints with a Cu content ranging from 20 wt% to 80 wt% could form full intermetallic compounds within 2 min with the shear strength reaching 120 MPa. Specifically, Cu6Sn5, 'island-like' Cu3Sn, and sintered Cu generated successively in the bondline center with the increasing Cu content. All failures occurred within the bondline indicating a higher interface bonding quality, while the 'island-like' Cu3Sn enhanced the shear strength. This die attach process is compatible with current commercial SiC die attach process with lower material cost as well as high efficiency, enabling the Cu-Sn nanoparticle film to be a promising material for high-reliability power electronic packaging.

Mesoporous confined Pt-based intermetallic compound with wrinkled carbon to enhance the performance towards oxygen reduction reaction for proton exchange membrane fuel cells

The formation of small-sized (<5 nm) and high-loading (>50 wt%) Pt-based intermetallic compound structures commonly requires thermal treatment to conquer the atom-ordering barrier, which inevitably causes severe nanoparticle agglomeration and hence reduces oxygen reduction reaction activity. Herein, we provided a synthetic wrinkled carbon support by vapor deposition from methane (CH4), and then we utilized the carbon to synthesize sub-5 nm high-loading (50.6 wt%) Pt3Co1 intermetallic compound by mesoporous confinement effect. Structural characterizations reveal that the nanoparticles are mainly located in the pores of the mesoporous carbon with an average size of ca. 4.1 nm, corroborating the confinement effect of the mesoporous structure. As a consequence, the Pt3Co1 intermetallic compound catalyst exhibits superior oxygen reduction reaction activity with a mass activity (@0.9V) of 0.35 A/mgPt and satisfactory durability with a mass activity decline by 22% after 40k-cycles accelerated durability test. Membrane electrode assembly with the resultant catalyst delivers the desirable performance with the peak power density of ca. 1.0 W/cm2 while lowering the Pt loading to 0.1 mg/cm2, suggesting the practical application potential in low-Pt proton exchange membrane fuel cells.

High-Loading Platinum-Cobalt Intermetallic Compounds with Enhanced Oxygen Reduction Activity in Membrane Electrode Assemblies

Platinum-based intermetallic compounds (IMCs) are emerging as promising oxygen reduction reaction (ORR) catalysts in proton exchange membrane fuel cells (PEMFCs). However, large-scale synthesis of supported IMCs catalysts with small particle size and high loading remains a significant challenge, greatly hindering the applications of IMCs in PEMFCs. Herein, carbon-supported PtCo IMCs with a metal loading of ∼40% and a mean size of ∼5 nm were successfully prepared via a simple impregnation method and display excellent performances in membrane electrode assemblies (MEA). The ordering degree of the PtCo IMCs can be tuned by carefully manipulating the annealing conditions. X-ray photoelectron spectroscopy characterizations demonstrate that the electronic interactions between Pt and Co are strengthened due to highly ordered structure of PtCo IMCs, thus promoting the ORR performance. The optimized PtCo IMCs exhibit an excellent ORR performance with a specific activity of 2.02 mA cm−2 and mass activity of 0.92 A mgPt−1 at 0.9 V (vs. RHE), which are approximately 5 times and 6 times higher than those of the commercial Pt/C. More importantly, the PtCo IMCs also display enhanced performance in MEA, and the power density at 1.5 A cm−2 and 2.5 A cm−2 is 0.949 W cm−2 and 1.244 W cm−2, respectively, thus reducing the Pt usage by 40% compared to Pt/C. This work offers a facile route for the scale preparation of platinum-based intermetallic compounds and promotes their practical applications in PEMFCs.

Stability of intermetallic compounds: Geometrical and topological aspects

We have applied a universal geometrical-topological approach to analyze 23507 robust crystal structures of intermetallic compounds, which are deposited in the Inorganic Crystal Structure Database. All the structures were represented as three-periodic nets and arranged into 2551 topological types each of which possesses a unique system of interatomic bonds. For all 104309 topologically different atoms in these structures their environments (local atomic configurations, LACs) were explored within the first and second coordination shells. In total, 5251 topologically distinct types of coordination polyhedra and 21450 types of two-shell LACs were distinguished and deposited into our interactive database system TopCryst. We have found that the local density of the nearest environment of an atom naturally depends on its coordination number (CN) with a maximum at CN = 9. It was shown that LACs at CN ≥ 9 follow the close packing model of hard balls with Slater's atomic radii. At lower CNs, covalent interactions make a significant contribution that results in a decrease of the local density. Resting upon the dependence between the local density and CN we have proposed criteria for the estimation of the geometric instability (disbalance) of both a separate LAC and the whole intermetallic structure. We have revealed that strong geometric disbalance can be caused by errors in the structural data, incorrect description of the crystal structure, non-metallic nature of the chemical bonding or metastability of the crystalline phase. Thus the instability criteria can serve as important indicators of the structure inconsistency that is especially useful for checking crystallographic information on intermetallics or validating the structural models predicted by theoretical methods.

Microstructure evolution and mechanical properties of Sn-9Zn-2.5Bi-1.5In solder joints with aging treatment under various conditions

Sn-Zn system solder has been considered promising lead-free solder materials to replace Sn-Pb and Sn-Ag-Cu systems in various conditions, due to the performance characteristics of low melting point and high reliabilities. This study investigates the microstructure evolution and mechanical properties of Sn-9Zn-2.5Bi-1.5In (Sn-Zn) solder paste joints on Cu substrates with aging treatment, which are under various conditions of different paste thicknesses and reflow times. It is concluded that the intermetallic compounds (IMC) of Sn-Zn/Cu solder joints are Cu5Zn8 layers at all stages of aging. The microstructure of before-aging joints and evolution during aging is significantly affected by the reflow times, while slightly affected by the paste thicknesses. In all experimental conditions, the IMC layers gradually thicken and reach 4-5 μm when aging for 720 h. While Cu5Zn8 products are generated at the position of the original Zn phases or along the Sn grain boundaries in the solder matrix with the aging process. The unequal diffusion rates of Cu and Zn atoms create two types of joint voids which are accumulated by Zn vacancies in the solder and accumulated by Cu vacancies at the interface between the solder and IMC layer. The interface voids and coarsened crystal structure are identified as the main factor for joint failure during aging. Finally, the shear strength of the joints with the initial 3.5 μm thickness IMC layers can maintain at high values above 45 MPa, exhibiting satisfactory reliability, which indicates that the soldering process determines the initial IMC structure, and affects the joint reliability more than the aging process.

Ti-Cu積層造形合金における熱処理による析出形態の制御と機構解明

Intermetallic compounds (IMCs), known for their hardness, play an important role in the precipitation strengthening of alloys. However, precipitation in excessive amounts or as large particles can result in embrittlement of the material. Thus, controlling the distribution of IMCs among the matrix is crucial for the design of strong and ductile alloys. In this research, a supersaturated Ti-Cu alloy formed by Laser Powder Bed Fusion (L-PBF) was heat-treated at different phase regions to produce lamellar, network, and dispersed distributions of Ti2Cu IMC precipitates. To comprehensively understand the formation mechanisms of each IMC distribution structure, in-situ microstructure observation was performed during the heat-treatments. The lamellar IMC structure obtained from heat treatment above the beta-transus temperature, was found to derive from the rejection of Cu atoms towards the boundaries of lamellar alpha grains formed during cooling. The network IMC structure obtained from heat-treatment in the α+β phase region involved the formation of a Cu-rich β-Ti layer between α-Ti grains during heating, and subsequent precipitation of Ti2Cu into an α-encapsulating network upon cooling. Finally, the dispersed structure of IMCs was observed to result from regular nucleation and growth of Ti2Cu during heat treatment in the α+IMC region.

Comparative study on solid-solid interfacial reaction and bonding property of Sn-Ag-Cu/Ni-P joints by laser and reflow soldering

PurposeLaser soldering has attracted attention as an alternative soldering process for microsoldering due to its localized and noncontact heating, a rapid rise and fall in temperature, fluxless and easy automation compared to reflow soldering.Design/methodology/approachIn this study, the metallurgical and mechanical properties of the Sn3.0Ag0.5Cu/Ni-P joints after laser and reflow soldering and isothermal aging were compared and analyzed.FindingsIn the as-soldered Sn3.0Ag0.5Cu/Ni-P joints, a small granular and loose (Cu,Ni)6Sn5 intermetallic compound (IMC) structure was formed by laser soldering regardless of the laser energy, and a long and needlelike (Cu,Ni)6Sn5 IMC structure was generated by reflow soldering. During aging at 150°C, the growth rate of the IMC layer was faster by laser soldering than by reflow soldering. The shear strength of as-soldered joints for reflow soldering was similar to that of laser soldering with 7.5 mJ, which sharply decreased from 0 to 100 h for both cases and then was maintained at a similar level with increasing aging time.Originality/valueLaser soldering with certain energy is effective for reducing the thickness of IMCs, and ensuring the mechanical property of the joints was similar to reflow soldering.

Enhancing mechanical properties via the dual effect of Ni addition and temperature gradient for 5 μm Cu/Sn-3.0Ag-0.5Cu/Cu transient liquid phase bonding

More recently, transient liquid phase bonding was widely considered to be a potential bonding method in 3D-IC technology as the full intermetallic compounds (IMCs) joints were characterized by superior bonding strength and reliable high temperature service. Nevertheless, preferred grain orientation and coarsening grains have been the shortcoming for traditional Cu/Sn/Cu transient liquid-phase bumps in heterogeneous integration. To alleviate such issues, Ni/Sn/Cu system was adopted to improve mechanical properties. Moreover, the thickness of joints was reduced to 5 μm for staying ahead of the trends of the miniaturization of electronic products. In this research, the microstructure of Cu/Sn-3.0Ag-0.5Cu/Cu, Cu/Sn-3.0Ag-0.5Cu/Ni, and Ni/Sn-3.0Ag-0.5Cu/Cu micro-bumps after transient liquid-phase bonding was investigated. With dissolution of Ni from substrate, the intermetallic compounds have diverse texture and refined grain. The distinct correlation between intermetallic compounds structure and Ni content was investigated on Ni substrate being in hot end or cold end. After shear testing, as compared to Cu/Sn-3.0Ag-0.5Cu/Cu, Ni/Sn-3.0Ag-0.5Cu/Cu showed extremely outstanding strength via replacing Cu substrate by Ni substrate. As compared to conventional Cu/solder/Cu full intermetallic structure, the shear strength increased 103.28% as Ni at the cold end. In this study, microstructure, grain analysis, and the fracture path observation after shear test were carried out to clarify the strengthening mechanisms of Ni.

Metallurgical and Mechanical Characteristics of an AA5183 Alloy Plate Performed by a Cold Metal Low-Power Additive Manufacturing Technology

In this work, an AA5183 alloy plate was successfully deposited by low-power cold metal transfer technology. The forming defects, microstructural characteristics, and mechanical properties were investigated. The results show that the number of defects increases gradually along the building direction of the deposited plate. X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, electron probe microanalysis, electron backscatter diffraction, and transmission electron microscopy were employed to study the distribution of alloying elements, deposited microstructural characteristics, and the crystal structure of intermetallic compounds in the Al alloy plate. The tensile samples perpendicular to the building direction presented greater tensile strength and superior plasticity compared to those parallel to the deposition direction. The average UTS was 327 ± 0.65 MPa and the average EL was 30.6 ± 2.0%. The UTS of conventionally forged 5083-H32 (Al-Mg4.5) alloy is 324 MPa; the UTS of extruded 5083-H116 (Al-Mg4.5) alloy is 305 MPa. Further, the strength of our prepared plate reaches the value needed for industrial applications of the 5083 Al alloy. The differences in the strength and plasticity of the samples assessed under multiple sampling methods were analyzed based on a synergistic strength–ductility mechanism.

A Critical Review on the Properties of Intermetallic Compounds and Their Application in the Modern Manufacturing

AbstractAdvancement in modern manufacturing processes is allowing researchers to develop new alloy configurations for different applications to reduce weight and increase efficiency. Many alloy combinations are produced that randomly generate different phases of intermetallic compounds (IMCs) in the structure during manufacturing which show unique mechanical and chemical properties. But, the fundamental knowledge of different IMCs is scattered across the material research domain. Thus, in this review, the crystal structures of IMCs are thoroughly discussed which are having structural and functional applications. Furthermore, the issues associated with the dissimilar Fe‐Al, Fe‐Ni, and Ni‐Al systems via modern manufacturing processes such as arc additive manufacturing have been discussed. Moreover, detailed knowledge of ferro‐nickel, nickel‐aluminides, and ferro‐aluminides formed at the interface during the dissimilar deposition in modern manufacturing is provided. Currently, a few transition metal IMCs and some Heusler alloys, are the most promising and are used in applications. The addition of a third alloying element provides the broadening effect on the phase domain of a specific IMC. Furthermore, it has been observed that modern manufacturing processes such as additive manufacturing and others are new and advanced manufacturing technologies used for dissimilar metal deposition, which can control the IMCs in a more favorable direction.

Ordered Mesoporous Carbon Confined Highly Dispersed PtCo Alloy for the Oxygen Reduction Reaction: The Effect of Structure and Composition on Performance

Pt-based catalysts are the most promising catalysts for proton exchange membrane fuel cells (PEMFCs) but still suffer from sluggish kinetics for the oxygen reduction reaction (ORR). Alloying Pt with transition-metal (M) elements is an efficient approach to modulate the electronic structure of Pt-based catalysts and improve the catalytic performance for the ORR. However, owing to the distinguishing surface state caused by different synthetic approaches, there still exist contradictory views about the relationship between the structure of Pt-based alloys and the catalytic performance for the ORR. In this work, PtCo alloys with a similar surface state but diverse structures and compositions are obtained by regulating the annealing temperatures and the precursor ratios. Accompanied by the structure and composition evolution, the electronic structure of Pt has also changed. PtCo@sOMC-900-1/3 with the intermetallic compound structure achieves the best kinetic activity as well as durability, indicating its potential for practical application. This work provides a more accurate understanding of the relationship between the alloy structure and the catalytic ORR performance and highlights a feasible strategy to mass-produce cathode catalysts for PEMFC applications.

Thermal aging impact on microstructure, creep and corrosion behavior of lead-free solder alloy (SAC387) use in electronics

This study aims to investigate the effects of thermal aging on microstructure changes, creep behavior, and corrosion properties of 95.5 wt%-Sn, 3.8 wt%-Ag, 0.7 wt%-Cu (also known as SAC387) solder alloy. Scanning electron microscope (SEM) was used to investigate the grain size, size of Intermetallic Compounds (IMCs) and growth rate, dispersion, and composition of SAC387. The creep and corrosion behaviors of SAC387 were also studied in detail. The results indicate that the increase in the thermal aging temperature of the material results in the fine and planar structures of IMCs. The creep test results showed that the alloy samples ruptured rapidly at a higher thermal aging temperature under the same load as compared to the lower thermal aging environmental temperature. It was also shown in the corrosion tests that thermal aging does affect the corrosion of the samples significantly.

The role of three-dimensional bulk clusters in determining surface morphologies of intermetallic compounds: Quasicrystals to clathrates.

Nanostructured alloy surfaces present unique physical properties and chemical reactivities that are quite different from those of the close-packed low-index surfaces. This can be beneficial for the design of new catalysts and electronic and data-storage devices. However, the growth of such surface nanostructures is not straightforward at the atomic scale. The cluster-based bulk structure of intermetallic compounds presents an original alternative to build surfaces with specific morphologies, in comparison to more traditional methods based on mechanical, chemical, or plasma treatments. It relies on their specific electronic structures-built from a network of bonds with a combination of ionic, covalent-like, and metallic characters, and also depends on the experimental conditions. In this paper, a few surface structures of cluster-based intermetallics are reviewed, with a special emphasis on quasicrystals and clathrates. We show how the intrinsic electronic properties of such compounds, as well as the surface preparation conditions, impact their surface morphologies, which can further influence the growth of atomic and molecular thin films at their surface.

Phase transformations of the nanostructured iron-platinum system upon heating

Joint reduction with hydrazine from aqueous solutions of precursors produced nanostructured powders of the Fe – Pt system in three characteristic phase regions. The samples were subjected to heat treatment in the range up to 800 ° C and characterized at all stages by X-ray diffraction and high-resolution electron microscopy; the elemental composition of the samples was refined by the method of optical emission spectroscopy with inductively coupled plasma. In the initially obtained samples, only a part of the substance is detected by diffraction-the largest, platinum-rich crystals with dimensions of about 10 nm (established from TEM images and broadening of diffraction lines). The fcc-type cubic lattice parameters and the composition of the observed crystals were estimated from the distances between the regular bands in TEM images, identified with atomic rows, based on the composition dependence of the bulk characteristics of mixed iron-platinum phases (according to ICDD databases). In the course of heating, the processes of phase transformation are traced in detail, the parameters of the resulting crystal structures of intermetallic compounds are fixed, and the mechanisms of these transformations are discussed. Based on the measured lattice parameters, the thermal expansion coefficients of some mixed phases are calculated and the phase compositions are estimated at different stages of heat treatment.

Intermetallic Compounds KnMm (М = Ag, Au, As, Sb, Bi, Ge, Sn, Pb): Geometrical and Topological Analysis, Cluster Precursors, and Self-Assembly of Crystal Structures

A geometrical and topological analysis and simulation of the self-assembly of the crystal structures of intermetallic compounds formed in the K–M (M = Ag, Au, As, Sb, Bi, Ge, Sn, Pb) systems have been performed using computation methods (the ToposPro software). The precursor metal clusters of KnMm crystal structures are determined based on the algorithms of structure-graph decomposition in cluster structures and construction of the basic net of structure in the form of a graph with nodes corresponding to cluster centers. Tetrahedral metal clusters, forming packings in the K3Bi-cF16, K3Bi-hP8, K2As2-oP16, K2Sb2-mP16, and K2Sb2-mP32 crystal structures; tetrahedral metal clusters and spacers for the K(K2As2)2-mC18, K4(Pb4)-tI64, and K2(Au4)-hP12 structures; polyhedral metal clusters KK4Pb12 and spacers for the Pb12K(K4Pb12)-cI58 structure; and dodecahedral metal clusters KGe20 and spacers for the K3Ge3(KGe20)-cP54 structure have been found. The symmetry and topology code of the self-assembly of crystal structures of intermetallic compounds KnMm has been reconstructed from precursors $$S_{3}^{0}$$ in the following form: primary chain $$S_{3}^{1}$$ → microlayer $$S_{3}^{2}$$ → microframework $$S_{3}^{3}$$ .

Intermetallic Compounds NakMn (М = K, Cs, Ba, Ag, Pt, Au, Zn, Bi, Sb): Geometrical and Topological Analysis, Cluster Precursors, and Self-Assembly of Crystal Structures

A geometrical and topological analysis has been performed, and self-assembly of the crystal structures of intermetallic compounds formed in the Na–M (M = K, Cs, Ba, Ag, Pt, Au, Zn, Bi, Sb) systems has been simulated using computer methods (the ToposPro software). The NakMn precursor metal clusters of the crystal structures are determined based on the algorithms of structural-graph decomposition in cluster structures and construction of the basic net of the structure in the form of a graph whose nodes correspond to the cluster centers. The tetrahedral metal clusters M4, forming packets in the Na3Bi-hP8, Na2Bi2-tP4, and Na2Sb2-mP16 crystal structures; tetrahedral metal clusters M4 and spacers for the Na2(Au4)-cF24 and Ba2(Na4)-hP12 framework structures; octahedral clusters M6 for the Na4Au2-tI12 structure; octahedral M6 and tetrahedral M4 metal clusters for the Na2(Na4)(Ba6)-cF96 and Au2(In4)(Na6)-cF96 structures; and icosahedral metal clusters M13 for the Na(Zn13)-cF116 structure are found. The symmetry and topology code of the self-assembly of crystal structures of NakMn intermetallic compounds has been reconstructed from precursor metal clusters $$S_{3}^{0}$$ in the following form: primary chain $$S_{3}^{1}$$ → microlayer $$S_{3}^{2}$$ → microframework $$S_{3}^{3}$$ .

Intermetallic Compounds LikMn (M = Ag, Au, Pt, Pd, Ir, Rh): Geometrical and Topological Analysis, Tetrahedral Cluster Precursors, and Self-Assembly of Crystal Structures

A combinatorial and topological analysis has been performed and self-assembly of the crystal structures of intermetallic compounds formed in the Li–M (M = Ag, Au, Pt, Pd, Ir, Rh) systems has been simulated using computer methods (the TOPOS program package). The LikMn precursor metal clusters are determined based on the algorithms of graph expansion in cluster structures and construction of basic 2D and 3D nets in the form of graphs, the nodes of which correspond to the cluster centers. The tetrahedral metal clusters M4, forming packets in the (LiPd3)(Pd4)-cF32, (Li2Rh2)(Rh4)-oI8, (Li2Pd2)(Pd4)-mP4, LiAu3-cP4, Li1.84Ag2.16-cF4, Li2Ag2-tI8, Li2Pd2-cP2, Li2Rh2-hP2, and Li3Pd-cF16 crystal structures; tetrahedral metal clusters M4 and spacer atoms for the Li2(Pt4)-сF24 framework structure; and two-layer clusters 0@М4@M22 for the (Li4)(Li12Ag10)-cI52 structure are found. The symmetry and topology code of self-assembly of the crystal structures of LikMn intermetallic compounds has been completely reconstructed from precursor metal clusters $$S_{3}^{0}$$ in the following form: primary chain $$S_{3}^{1}$$ → microlayer $$S_{3}^{2}$$ → microframework $$S_{3}^{3}$$.

Intermetallic Compounds as an Alternative to Single‐atom Alloy Catalysts: Geometric and Electronic Structures from Advanced X‐ray Spectroscopies and Computational Studies

AbstractPt−Fe intermetallic compound (IMC) catalysts, including Pt3Fe, PtFe and PtFe3, are shown to have advantageous catalytic properties similar to those reported for single‐atom alloy catalysts. Suppresion of the Pt ensembles responsible for hydrogenolysis results in high olefin selectivity during propane dehydrogenation. In situ resonant inelastic X‐ray scattering (RIXS) results and density functional theory calculations show that these changes are associated with a decrease in the average energy of the filled 5d states of Pt in the Pt−Fe intermetallic compound structures compared to monometallic Pt, accompanied by an increase in the average energy of the unfilled valence bands. The decrease in energy of the filled Pt 5d orbitals increases with increasing Fe content in the IMC, i.e. PtFe3&gt;PtFe&gt;Pt3Fe. These results demonstrate that by altering the stoichiometry of IMC catalysts it is possible to control both the ensemble size and electronic properties of active sites, which affords another mechanism for tuning catalytic properties, in addition to changing promoter metals. The present study demonstrates the potential of ordered intermetallic compounds as an alternative to traditional solid‐solution single‐atom alloys to serve as catalysts with well‐defined and uniform active sites.