Lattice Parameters Research Articles

Strain‐Engineered Level Alignment in the MoTe2/WSe2 Heterobilayer

When stacked into heterostructures, layered transition metal dichalcogenides (TMDCs) exhibit peculiar electronic and optical properties that may differ substantially from those of their constituents and that largely depend on the level alignment. For example, the MoTe2/WSe2 heterobilayer exhibits a type I band lineup, which can be exploited in emitting devices but limits charge separation. In this first‐principle study based on density functional theory and many‐body perturbation theory, strain is proposed as an effective means to make MoTe2/WSe2 a type II heterostructure. By exploring several configurations where biaxial strain is applied to either or both monolayers, the top of the valence band and the bottom of the conduction band are found at different points in k‐space leading to an indirect‐to‐direct bandgap transition when the lattice constant of WSe2 is expanded by 3.2% or more. In terms of optical properties, all considered systems exhibit a first dark excitation, consistently shifting in energy with the direct electronic gap, while the absorption onset does not vary significantly with strain. Our findings suggest strain as a powerful tool for fine tuning the electronic and optical properties of TMDC heterostructures while preserving their fundamental characteristics, thus opening new avenues for designing optoelectronic applications.

Customizing Bonding Affinity with Multi‐Intermediates via Interfacial Electron Capture to Boost Hydrogen Evolution in Alkaline Water Electrolysis

AbstractDeveloping efficient and earth‐abundant alkaline HER electrocatalysts is pivotal for sustainable energy, but co‐regulating its intricate multi‐step process, encompassing water dissociation, OH− desorption, and hydrogen generation, is still a great challenge. Herein, we tackle these obstacles by fabricating a vertically integrated electrode featuring a nanosheet array with prominent dual‐nitride metallic heterostructures characterized by impeccable lattice matching and excellent conductivity, functioning as a multi‐purpose catalyst to fine‐tune the bonding affinity with alkaline HER intermediates. Detailed structural characterization and theoretical calculation elucidate that charge redistribution at the heterointerface reduces the O p‐W d and H s‐W d interactions vs. single nitride, thereby enhancing OH− transfer and H2 release. As anticipated, the resulting WN‐NiN/CFP catalyst demonstrates a gratifying low overpotential of 36.8 mV at 10 mA/cm2 for alkaline HER, while concurrently maintaining operational stability for 1300 h at 100 mA/cm2 for overall water splitting. This work presents an effective approach to meticulously optimize multiple site‐intermediate interactions in alkaline HER, laying the foundation for efficient energy conversion.

Enabling Interfacial Lattice Matching by Selective Epitaxial Growth of CuS Crystals on Bi2WO6 Nanosheets for Efficient CO2 Photoreduction into Solar Fuels

AbstractPhotocatalytic CO2 reduction serves as an important technology for value‐added solar fuel production, however, it is generally limited by interfacial charge transport. To address this limitation, a two‐dimensional/two‐dimensional (2D/2D) p‐n heterojunction CuS‐Bi2WO6 (CS‐BWO) with highly connected and matched interfacial lattices was designed in this work via a two‐step hydrothermal tandem synthesis strategy. The integration of CuS with BWO created a robust interface electric field and provided fast charge transfer channels due to the work function difference, as well as highly connected and matched interfacial lattices. The p‐n heterojunction combination promoted the electron transfer from the Cu to Bi sites, leading to the coordination of Bi sites with high electronic density and low oxidation state. The Bi sites in the BWO nanosheets facilitated the adsorption and activation of CO2, and the generation of high‐coverage key intermediate b‐CO32−, while CuS (CS) acted as a broad light‐harvesting material to provide abundant photoinduced electrons that were injected into the conduction band of BWO for CO2 photoreduction reaction. Remarkably, the p‐n heterojunction CS‐BWO exhibited average CO and CH4 yields of 33.9 and 16.4 μmol g−1 h−1, respectively, which were significantly higher than those of CS, BWO, and physical mixture CS‐BWO samples. This work provided an innovative design strategy for developing high‐activity heterojunction photocatalyst for converting CO2 into value‐added solar fuels.

Effect of Ta content on elastic properties and magnetic properties of Zr-Ta binary alloys via first-principles calculation

Abstract β-type Zirconium alloys are promising biomedical implant materials, the elastic and magnetic properties of which are of great importance to be studied. In this work, β-type Zr1-xTax binary alloys (x=0.0625, 0.125, 0.1875, 0.25, 0.3125, 0.375, 0.4375, 0.50, 0.5625, 0.625, 0.6875, 0.75, 0.8125, 0.875, 0.9375) were established. The effects of Ta content on lattice constant, elastic properties and magnetic properties of β-type Zr-Ta alloys were investigated via first-principles calculations, the calculated results were also verified through experiments. The results shown that with the increase of Ta content, the lattice constant and total energy of β-type Zr-Ta alloys gradually decreased, the elastic moduli of E, K and G increased on the whole, and the magnetic moment generally increased first and then decreased. The changing trend of elastic and magnetic properties were consistent between experimental and calculated results. Notably, Zr0.875Ta0.125 exhibited the lowest Young’s modulus and magnetic susceptibility among the β-type Zr-Ta alloys, which was one-third that of Ti-6Al-4V, meeting the requirements for low Young’s modulus and low magnetism, and can be anticipated to be promising biomedical implant materials.

Substrate-induced strain upshot on the optical and optoelectronic properties of trilayer MoS2.

The characteristics of 2D layered MoS2 film are highly dependent on the substrate it is grown on which leaves us privileged to achieve unique and tunable properties. In this study, trilayer MoS2 films have been grown on fused quartz, crystalline quartz (z-cut), sapphire (0001), and silicon (100) substrates. MoS2 film grows as freestanding on amorphous fused quartz, while it experiences an in-plane tensile strain on the sapphire and silicon. Unprecedentedly we show that due to a large mismatch in the lattice parameter as well as in the thermal expansion coefficient, MoS2 grows with a significant compressive strain both along both in-plane on the crystalline quartz. The developed strain causes an alteration in its electronic structure, causing a 30 meV blue shift in the photoluminescence peak and an increased band gap in addition to fewer sulphur vacancies. Comparatively, the film on sapphire having tensile strain along the in-plane exhibits more sulphur vacancies increasing the electron density. The photoresponse time, photosensitivity, and charge separation distinctly vary for the MoS2 films depending on the substrates. This study underscores the influence of substrate on MoS2 film opening further research scopes on tunable properties owing to 2D layer-substrate interactions.

Mechanical, electronic, optical, and thermoelectric properties of Rb2TlGaX6 (X = F, I) lead free double perovskites: A first-principles study

Abstract Halide perovskites play an important role in the renewable energy industry and are the top substitutes for Pb-halide perovskites. This study investigates the structural, mechanical, electronic, optical, and thermoelectric properties of the double halide perovskites Rb2TlGaX6 (X = F, I) using density functional theory (DFT) at WIEN2k interfaces. The structural, mechanical, and thermal stabilities are evaluated using the tolerance factor, Born-Huang criteria, and negative formation energy. The obtained lattice constants are 9.31 Å and 24.93 Å, for Rb2TlGaF6 and Rb2TlGaI6 respectively. Rb2TlGaF6 is brittle and Rb2TlGaI6 is ductile. Both compounds exhibit anisotropic behavior. The indirect semiconducting nature (L-X) is demonstrated by the estimated bandgap values of 6.05 eV (4.31 eV) and 1.06 eV (0.52 eV), for Rb2TlGaF6 and Rb2TlGaI6 respectively, using the TB-mBJ (PBE-GGA) potential. Distinctive optical characteristics are studied, including the dielectric function, loss function, conductivity, reflectivity, refractive index, and absorption coefficient. Based on the investigation, both materials exhibit excellent optical conductivity, high light absorption throughout the UV–visible spectrum, and low reflection (within 20% for Rb2TlGaF6 and 40% for Rb2TlGaI6). Lastly, various thermoelectric properties are explored by varying the temperature. Both compounds show a high Seebeck coefficient and low thermal conductivity. The maximum figure of merit (ZT) obtains of 0.61 and 0.81, for Rb2TlGaF6 and Rb2TlGaI6, respectively. These results demonstrate the suitability of Rb2TlGaF6 and Rb2TlGaI6 for thermoelectric and photovoltaic applications.

Heterostructural interface engineering for ultrawide-gap nitrides from first principles: TaC / AlN and TaC / GaN rocksalt-wurtzite interfaces

Epitaxial lattice matching is an important condition for the formation of coherent interfaces with low defect densities. However, lattice-matched substrates with the same crystal structure as the active layer are often not available, suggesting opportunities for utilizing heterostructural interfaces. For example, at high Al contents that are interesting for ultrawide-gap applications in power electronics, AlxGa1−xN semiconductor alloys in the (0001) orientation of the wurtzite (wz) structure become lattice-matched to (111)-oriented rocksalt (rs) TaC substrates. To predict the expected interface atomic structures under different synthesis conditions, we perform high-throughput density-functional-theory calculations, using an algorithm for systematic sampling of the possible stacking sequences of the atomic layers on the in-plane hexagonal lattice. The approach considers octahedral, tetrahedral, and prismatic coordination motifs, and is generally applicable for the modeling of commensurate rs/wz heterostructural interfaces. Our results provide guidance for synthesis control of substrate-film bonding and the polarity of ultrawide-gap AlxGa1−xN alloys on TaC substrates. Published by the American Physical Society 2024

Asymmetric and Ultrasensitive Structural Color Response in Nanochain‐Embedded Photonic Composites

AbstractMechanochromic photonic crystals, capable of altering structural colors in response to external forces, are emerging intelligent materials in various fields, such as visual sensors and anti‐counterfeiting technologies. However, conventional mechanical responses of photonic crystals mainly rely on stretching or compression, resulting in symmetric and limited mechanochromic effects due to restricted changes in lattice spacing, particularly limiting the recognition of the direction of force. Here, asymmetric and ultrasensitive structural color responses are reported in colloidal photonic composites featuring embedded one‐dimensional (1D) photonic nanochains of colloidal particles based on shear‐induced lattice orientation change. It is shown that shearing deformation tilts the photonic nanochains within the polymer matrix, leading to a remarkable and asymmetric color shift depending on shear force and observing directions. The asymmetric response encourages to develop ultrasensitive twist sensors capable of detecting subtle twisting movements as low as 0.2° and twist direction. Furthermore, by integrating magnetic and deformation orientation control, dynamic optical anti‐counterfeiting labels capable of displaying highly intricate patterns are devised. This unique shear‐induced color‐shifting mechanism expands the responsiveness of mechanochromic materials, with broad implications in many other areas, including structural health monitoring, soft robotics, and artificial skin.

Effect of Different Doping Concentrations on the Properties of Fe2+:ZnSe and Fe2+, Cr2+:ZnSe Crystals Grown by the Chemical Vapor Transport Method.

The Fe2+:ZnSe crystal is an important material for 3-5 μm mid-infrared lasers. In this work, we have grown different doping concentrations of Fe2+:ZnSe and Fe2+, Cr2+:ZnSe by the chemical vapor transport method. The doped crystals have the same structure. The lattice constant increases slightly with a higher Fe2+ concentration, while the doped Cr2+ has a great influence on the lattice constant. Besides, with a higher Fe2+ concentration, the TO mode has no change and the LO mode presents a small blue shift. The doped ZnSe crystals all have a wide absorption peak in the range of 2.3-4.5 μm, and these absorption peaks widen with the increase of the Fe2+ doping concentration. Besides, in the range of 5-20 μm, the crystals have good transparency. The concentrations of 3, 2, and 1% Fe2+ samples are calculated to be 4.15 × 1019, 3.27 × 1019, and 3.02 × 1019 cm-3, respectively, and the Fe2+ concentration of the Fe2+, Cr2+:ZnSe sample is 3.71 × 1019 cm-3. The band gap decreases from 2.52 to 2.27 eV with a higher Fe2+ doping concentration. Therefore, we can modulate the absorption bandwidth and band gap by doping the ion concentration, which is more suitable for developing mid-infrared gain medium applications.

Superconductivity in Ternary Germanite TaAl x Ge2-x with a C40 chiral structure

Abstract We report a new family of chiral intermetallic superconductors TaAl x Ge2-x . The mother compound TaGe2 has a C40-type chiral hexagonal crystal structure with a pair of enantiomorphic space groups of P6222 and P6422. By substituting Ge with Al, TaAl x Ge2-x polycrystals with the C40 structure were synthesized with Al substitution x from 0 to 0.8. Magnetic susceptibility, magnetization curves and electrical resistivity revealed that TaAl x Ge2-x with x of 0.2 to 0.4 was a type-II superconductor with a superconducting transition temperature T c of 2.0 to 2.2 K. The superconductivity disappeared at with x less than 0.2 or was largely suppressed at with x of 0.5 or more, although all the measurements were performed at temperatures above 1.8 K. An emergence of superconductivity is discussed in terms of the lattice constants changes with the Al substitution.

Exploring the phase composition and crystal structure of potassium-doped copper sulfide

This study investigates the phase composition, crystal structure, and phase transitions of potassium-substituted copper sulfide (KxCu1.97-xS), focusing on the effects of potassium doping on the material’s properties. Using X-ray diffraction analysis, we identified the structural characteristics of potassium-doped variants, confirming their retention of the monoclinic chalcocite structure (P21/c) with slight modifications in lattice parameters. The incorporation of potassium ions resulted in observable changes in the unit cell dimensions, suggesting enhanced ionic interactions and potential impacts on electronic conductivity. The thermoelectric coefficient, electro-conductivity, and thermoelectric power were also examined, revealing that potassium doping could stabilize certain phases under varying temperature conditions. This work provides valuable insights into the structure-property relationships in copper sulfides, highlighting the potential for tailored materials in thermoelectric applications and other advanced technologies. Future studies will explore the implications of these findings for optimizing the performance of potassium-doped copper sulfides in practical applications.

Tuning the Magnetism in Ultrathin CrxTey Films by Lattice Dimensionality

Abstract2D magnetic crystals with atomic thickness exhibit intriguing physical properties, which have attracted considerable research interest in the related materials’ family, both in fundamental research and in developing spintronic devices. The recent discovery of some non‐van der Waals 2D magnetic crystals expands the systems. Nevertheless, the relationship between the dimensionality of microscopic magnetic exchange interactions and macroscopic magnetic properties at the 2D limit remains to be fully elucidated. Here, we have fabricated mono‐phased continuous ultrathin CrTe2 and Cr3Te4 films by molecular beam epitaxy and elucidated the diverse magnetism tuned by the dimensionality of exchange interactions by a joint study of spin‐polarized scanning tunneling microscopy, magnetization, magneto‐transport measurements, and density functional theory calculations. The transition from a zigzag‐antiferromagnetic order in the monolayer CrTe2 to a ferromagnetic (FM) order in the second‐layer CrTe2 is confirmed, which is driven by their varied in‐plane lattice constants induced change of 2D exchange interactions. A robust FM state with large perpendicular magnetic anisotropy in Cr3Te4 is observed, originating from its strong 3D exchange interactions. The observed evolution of magnetism demonstrates that the dimensionality of magnetic exchange interactions strongly influences magnetism even at the 2D limit.

Growth Phenomena and Bandgap Shift in Melt‐Grown β‐(InxGa1−x)2O3 Alloys

β‐Ga2O3 is an emerging ultra‐wide bandgap semiconductor with great promise for power electronics and optoelectronics. Alloys in the In2O3‐Ga2O3 system are interesting for optoelectronic applications, particularly where bandgap tuning is desirable. Herein, β‐(InxGa1–x)2O3 alloys with target compositions x = 0.025 or 0.10 are grown from the melt using the Czochralski and vertical gradient freeze techniques. Growth with 10 mol% In yields only small, needle‐like crystals, while 2.5 mol% In allows growth of centimeter‐sized single crystals. A substantial degree of indium segregation is unveiled by spatial measurements of lattice parameters and the bandgap. The bandgap decreases by a maximum of 0.28 eV in the case of the highest In content crystals. Z‐contrast transmission electron microscopy confirms a solely octahedral coordination of In in the β‐Ga2O3 lattice. With indium concentrations higher than 2.5 mol%, samples contain micron‐scale voids that impart a dark coloration. All measured crystals are electrically conductive, with carrier concentrations varying 1016–1017 cm−3 depending upon the location of the sample in the growth. Lastly, a unique luminescence with unknown origin centered around 2.0 eV is revealed by photoluminescence spectroscopy.

Greatly Enhanced Oxygen Reduction Reaction in Anion Exchange Membrane Fuel Cell and Zn-Air Battery via Hole Inner Edge Reconstruction of 2D Pd Nanomesh.

Platinum group metals (PGM) have yet to be the most active catalysts in various sustainable energy reactions. Their high cost, however, has made maximizing the activity and minimizing the dosage become an urgent priority for the practical applications of emerging technologies. Herein, a novel 2DPd nanomesh structure possessing hole inner reconstructed edges (HIER) with exposed high energy facets and overstretched lattice parameters is fabricated through a facile room-temperature reduction method at gram-scale yields. The HIER enhances the catalytic performance of Pd in electrochemical oxygen reduction reaction (ORR), achieving superior mass activity (MA) of 2.672 A mgPd -1, which is 27.8 fold and 23.6 fold higher, respectively, than those of the commercial Pt/C (0.096 A mgPt -1) and Pd/C (0.113 A mgPd -1) at 0.9 VRHE. Most significantly, in H2-air anion exchange membrane fuel cell (AEMFC) and Zn-air battery (ZAB) applications, this unique Pd catalyst delivers a much-outperformed peak power density of 0.86 and 0.22W cm-2, respectively, compared with 0.54 and 0.13W cm-2 of the commercial Pt/C catalyst, indicating a novel pathway in electrocatalyst designs through HIER engineering.

Structural modifications of BiOBr nanoplates by electron beam irradiation

Abstract In this study, BiOBr nanoplates are synthesized through the hydrothermal method, then samples have been irradiated by an electron beam of 10 MeV energy to deliver doses of 100 kGy and 500 kGy. XRD and Raman investigations corroborated the presence of a pure phase in all nanoplate samples. The sharp and narrow peaks in XRD indicate well crystalline in nature of the samples, which decreases with increasing the electron dose as confirmed by the decay in peak intensity. Conversely, the peak position shifts at lower angle with increasing the electron dose. Structural factors including lattice parameter, dislocation density, cell volume, microstrain, as well as stacking fault have been found to change due to electron beam irradiation. We employed the Debey-Scherrer formula (D-S), Size Strain Plot method (SSP), and Halder Wagner (H-W) methods to determine the crystal size and strain of purified and irradiated BiOBr nanoplates. It has been found that the size of the crystallites increases nonlinearly as the irradiation dose increases. All three of the aforementioned calculation methods have observed this trend. Strain and dislocation density exhibited the opposite trend of crystallite size, as they decreased as the irradiation dose increased. The dislocation density, strain, and crystallite size values are nearly identical for the SSP and H-W procedures, while the D-S method exhibits values with deviation. The tetragonal structure and the Raman active mode, which we have identified as closely resembling those in other literature of this composition, are discussed in the respective section. Because of their intriguing phase strength, the synthesized nanoplates may be suitable for the degradation of organic pollutants and the separation of water through photo-electrocatalysis.

Steady-State Inverse-Temperature Crystallization Enabling Low Defect Perovskite Single Crystal and Efficient X-Ray Detectors.

Organic-inorganic halide perovskite single crystals (SCs) have shown great potential in radiation detection applications due to their large radiation stopping power and excellent carrier transport properties. The spatial-confined inverse-temperature crystallization (ITC) method has been widely adopted to obtain large-sized SCs. However, they usually face the problems of uneven stress distribution and high defect density due to the limited crystal growth space and varied growth rate with the increase in temperature, making it difficult to fabricate highly sensitive and stable radiation detectors. In this study, the steady-state inverse-temperature crystallization method (SS-ITC) is developed to regulate the growth process of SCs by controlling the growth speed precisely to achieve a constant rate of growth as the temperature increases. Compared with the conventional ITC-grown samples, the lattice spacing of SCs prepared by the SS-ITC method is reduced by 1.2% due to tensile stress relaxation, resulting in a lower defect density of 7.93×109cm-3 and a remarkable uniformity over a large area. As a result, the co-planar X-ray detectors based on these high-quality SCs exhibit a high sensitivity of 1.67×105 µC Gyair -1cm-2, representing the best performing MAPbBr3-based X-ray detectors reported to date.

Role of harmonic and anharmonic interactions in controlling the cooperativity of spin-crossover molecular crystals

We present a theoretical model of spin transitions in homogeneous spin-crossover (SCO) materials, based on the description of the interactions between SCO molecules by the Lennard-Jones potential in which the equilibrium distances depend on the spin states of the linked molecules. By expanding the potential to order 3 considering a homogeneous lattice spacing, we demonstrate that the present model is isomorphic with an Ising-like model combining infinite long-range “ferromagnetic-like” interactions, competing with short-range “antiferromagnetic-like” between nearest neighbors in the case of harmonic interactions. When an anharmonic contribution is included, the short-range interaction becomes dependent on the average high-spin fraction, and changes its sign along the spin transition. The thermodynamic properties of the model were first investigated analytically in mean field approximation for both harmonic and anharmonic cases, for which we clarify the conditions for obtaining gradual and first-order transitions. Moreover, we demonstrated that within this approximation, the strength of the antiferromagnetic-like interactions are insufficient to produce multistep transitions. In contrast, the resolution of the previous emerging Ising-like model by Monte Carlo simulations demonstrated the possibility of obtaining gradual, first-order and two-step transitions as a result of the antagonism between long- and short-range interactions. Overall, the obtained results demonstrate the suitability of the present theoretical model to describe cooperative SCO materials. The key message of our paper is that our model can be used to predict complex behavior of spin-crossover crystals. Published by the American Physical Society 2024

Modeling martensitic transformation temperatures in Zirconia–Ceria solid solutions using machine learning interatomic potentials

Abstract Shape memory ceramics (SMCs), while exhibiting high strength, sizeable recoverable strain, and substantial energy damping, tend to shatter under load and have low reversibility. Recent developments in SMCs have shown significant promise in enhancing the reversibility of the shape memory phase transformation by tuning the lattice parameters and transformation temperatures through alloying. While first-principles methods, such as density functional theory (DFT), can predict the lattice parameters and enthalpy at zero Kelvin, calculating the transformation temperature from free energy at high temperatures is impractical. Empirical potentials can calculate transformation temperatures efficiently for large system sizes but lack compositional transferability. In this work, we develop a model to predict transformation temperatures and lattice parameters for the Zirconia–Ceria solid solutions. We construct a machine learning inter-atomic potential (MLIAP) using an initial dataset of DFT simulations, which is then iteratively expanded using active learning. We utilize reversible scaling to compute the free energy as a function of composition and temperature, from which the transformation temperatures are determined. These transformation temperatures match experimental trends and accurately predict the phase boundary. Finally, we compare other relevant design parameters (e.g. transformation volume change) to demonstrate the applicability of MLIAPs in designing SMCs.

Structural, Electronic, and Magnetic Properties of Gd-Substituted Bi2Fe4O9 Multiferroic: A Combined Experimental and DFT Approach

Abstract We present the structural, electronic, and magnetic properties of Gd3+ substituted Bi2Fe4O9 (BFO) via experimental analysis as well as density functional theory (DFT). Rietveld refined X-ray diffraction data shows phase purity of the samples having orthorhombic phase with space group: ‘Pbam’. Gd3+ ions substitution at Bi3+-site is confirmed by the shift in peaks ((002) and (220)) at higher 2θ angles as well as the reduction in lattice parameters. The PBE+U calculations predict a band gap of 1.76 eV (BFO) and 1.6 eV (Gd substituted BFO) which is in close agreement with the experimental values. This reduction in band gap due to Gd3+ substitution enhances conduction in substituted samples. The calculated density of states illustrates considerable hybridization between Fe-3d and O-2p states with substantial overlap among the Bi-6p and O-2p states. Incorporating Gd3+ ions further introduces additional exchange interactions between Gd-Fet and Gd-Feo, thus leading to enhanced magnetization as well as an increase in antiferromagnetic transition temperature (TN). This characteristic feature is supported by temperature-dependent magnetic susceptibility (χ) and dχ/dT plots. Hence, our experimental and theoretical findings suggest that BFO and its substituted samples are potential multiferroic materials for various device applications.

Microstructure and Wear Behavior of AlxCoCuNiTi (x = 0, 0.4, and 1) High-Entropy Alloy Coatings

AlxCoCuNiTi (x = 0, 0.4, and 1) high-entropy alloy coatings on 45 steel substrates were prepared by laser cladding, and their phase structure, microstructure, element partition, and wear behavior were investigated. The results show that the AlxCoCuNiTi (x = 0, 0.4, and 1) coatings have a dual-phase structure of FCC and BCC. With the increase of x from 0 to 1, the content of the FCC phase decreases from 66.9 wt.% to 14.3 wt.%, while the content of the BCC phase increases from 33.1 wt.% to 85.7 wt.%. When x = 0.4, the lattice constants of the two phases are the largest, and their densities are the smallest. The microstructure of the AlxCoCuNiTi (x = 0, 0.4, and 1) coatings is composed of BCC-phase dendrites and FCC-phase interdendrite regions. Ti is mainly enriched in the primary phase or BCC dendrites, Cu is enriched in the interdendrite regions, and Al is enriched in the dendrites. The friction coefficients of AlxCoCuNiTi (x = 0, 0.4, and 1) coatings during wear tests are 0.691, 0.691, and 0.627, respectively. The lowering of the wear friction coefficient when increasing the Al content is mainly related to the change in phase structure, microstructure, and wear mechanism.