Lattice Positions Research Articles

Co ions doping enhances n-butanol sensing performance of In2O3 nanospheres

In this work, In2O3 nanospheres were synthesized using urea as a carbon template and modified with Co ions. The synthesized materials were characterized using various instruments to obtain information about the elemental composition and morphology of the materials. The results showed that Co ions replaced the lattice position of In ions and synthesized nanospheres aggregated from 20 nm particles. The results of gas sensitivity tests on all the samples showed that the response to 50 ppm n-butanol at 250 °C reached 540 when Co was doped up to 5 at%. In comparison, the sensor showed very low response to benzene gas with good selectivity. The high response of the sensor to n-butanol is due to the increase in vacancy oxygen content and redox reactions due to the multivalent nature of Co ions. The article concludes with a detailed analysis of the sensing mechanism.

Developing advanced oxygen electrodes for reversible protonic ceramic electrochemical cells via controlled bismuth doping on diverse perovskite lattice positions

The development of reversible protonic ceramic electrochemical cells (R-PCECs) is hampered by insufficient oxygen electrode activity. This study addresses this challenge by introducing bismuth (Bi) into different lattice sites (A-site, B-site, or both) of Ba(Co0.7Fe0.3)0.85Ta0.15O3-δ (BCFT) to develop novel oxygen electrode materials. Extensive characterizations and density functional theory calculations demonstrate that introducing Bi onto the B-site promotes oxygen vacancy formation and hydration, facilitates proton transportation and improves oxygen exchange ability, leading to the enhanced catalytic activity. In contrast, Bi on the A-site hinders performance. R-PCEC using Ba(Co0.7Fe0.3)0.75Bi0.10Ta0.15O3-δ (B-BCFT) oxygen electrode achieves exceptional performance in fuel cell (1.485 W cm−2 at 650 °C) and electrolysis modes (−1.839 A cm−2 at 1.4 V and 650 °C). Notably, B-BCFT demonstrates outstanding operational stability, lasting for 150 h in both modes and enduring 35 cycles of reversible operation. These results make B-BCFT a promising oxygen electrode material candidate for R-PCECs.

Unusual Defect Chemistry of Thorium Doping of PbS.

The unusual defect chemistry of thorium doping in the PbS system was investigated computationally to answer several open questions arising from the experimental observations. These include finding Th in a +4 oxidation state in contrast to Pb, attracting more than two oxygen atoms on average per thorium and affecting the growth morphology of PbS and its electronic properties. We find Th to be energetically stable at the lead lattice position in PbS and to attract 2-3 oxygens, including in the adjacent interstitial position, which binds strongly to Th. This adjacent interstitial atom allows the +4 oxidation state of Th in PbS as observed experimentally. Furthermore, the bandgap of the ideal material increased due to Th incorporation, in agreement with experimental observations. Finally, we calculated the surface energies of the (100), (110), and (111) surfaces for the systems with and without thorium incorporation. Surfaces (100) and (110) were found to have negative surface energies; however, (111) surface energy was positive and, thus, preferred for the growth of Th-doped PbS thin films. These results correlate well with the experimentally observed surface topography change for PbS thin film growth from the (100) to the (111) surfaces with addition of Th.

Absolutely Structural Disorder Boosting Bandwidth toward Full-Spectrum White Light from Single Occupancy of Activator.

Achieving single-phase full-spectrum white light (SFWL) phosphors is a central goal in theoptical field because they simplify white-LEDs assembly and avoid long-term color instability. Despite many approaches are developed, current SFWL phosphors still suffer from chromaticity drift due to inconsistent thermal quenching of multiple emitting centers. Herein, an absolutely structural disorder strategy is established to develop a single-emitting center-based SFWL phosphor. Precisely controlling the flux added induces a structural translation from the absolutely ordered Y0.75Ta0.25O1.75:Bi3+ to the absolutely disordered Y0.785Ta0.215O1.715:Bi3+, as directly identified by STEM-HAADF analyses. Structural disorder enables Y0.785Ta0.215O1.715:Bi3+ to produce SFWL with the FWHM of 6194cm-1 (175nm) by employing a single activator site, a 1352cm-1 increase compared to the cyan-emitting Y0.75Ta0.25O1.75:Bi3+ despite Bi3+ occupies two lattice positions. This single-emitting center-based SFWL, coupled with minimal thermal expansion of the unit cell and inapparent spectral overlap of excitation and emission bands, ensure zero-chromaticity shift with elevated temperature. A prototype white-LEDs using Y0.785Ta0.215O1.715:Bi3+ as a single luminescent layer generates warm white light without perceptible CIE coordinates shift under various currents or after extremely long-term continuous operation. This work highlights the potential of structural disorder in designing SFWL phosphors with exceptional color stability.

Structure and tunable temperature coefficient of magnetization of Mn4-xGaxC alloys prepared by induction melting method

Abstract The magnetization of most magnetic materials decreases monotonically with increasing temperature. In this work, we found that the temperature coefficient of magnetization of Mn4-x Ga x C alloys can be tuned from negative values to positive values by controlling the composition x. The antiperovskite-type Mn4-x Ga x C (0.05≤x≤0.75) alloys were prepared by using induction melting method, which is more efficient in large-scale production and obtaining full-density alloys in comparison with the traditional solid-state-reaction method. The values of the temperature coefficient of magnetization of Mn4-x Ga x C change continuously from negative to positive with decreasing x. The Mn4-x Ga x C alloys with highly thermal-stable magnetization is expected to present in the composition range of 0.15<x<0.25. The saturation magnetization of Mn4-x Ga x C increases with increasing x, owing to the reduced number of antiferromagnetically coupled Mn atoms at the cubic corner with the face-centered Mn atoms. Most Mn4-x Ga x C alloys with varying x display near-zero remanent magnetization and coercivity at room temperature. The Currie temperature of Mn4-x Ga x C decreases with increasing x. The x-ray photoelectron spectra of Mn 2p, Ga 2p, and C 1 s reveal distinct splitting due to the diverse chemical states of these atoms at different lattice positions and/or phases. Our work has developed a class of alloys capable of offering a desired temperature coefficient of magnetization across a broad temperature range, thereby offering a method to manipulate the thermodynamics of magnetization.

Codoped germanene with 3p and 4p elements elements.

The relentless need for new materials to be used in electronic devices has opened new research directions in materials science. One of them involves using two-dimensional materials, among which there is current interest in using germanene. The heteroatom doping of germanene has been proposed as a possible approach to fine-tuning its electronic properties. However, this procedure is complicated because locating the dopants with a specific arrangement is challenging, thus achieving reproducibility. To avoid this problem, we propose the codoping of germanene to understand if dopants prefer to be agglomerated as observed for graphene or if they prefer to adopt a random disposition. Herein, we employed first-principles calculations to study 21 codoped germanene systems with one 3p (Al, Si, P, and S) and one 4p (Ga, As, and Se) element. Our results indicate that in the cases of AlP, AlS, GaP, GaS, GaAs, and GaSe codoped germanene, the dopants show a tendency to be located in specific lattice positions. The ortho disposition of dopants is preferred for AlP, AlS, GaP and GaS codoped germanene and their 4p counterparts GaAs and GaSe codoped germanene, and the materials showed interesting electronic propertiesmaking them suitable to develop germanene-based electronic materials. We utilized the M06-L, HSE06 methods accompanied by the 6-31G* basis sets to perform periodic boundary conditions calculations as implemented in Gaussian 09. The unit cells were sampled employing 100k-points for geometry optimizations and 2000k-points for electronic properties The ultrafine grid was employed. Results were visualized employing Gaussview 5.0.1. In addition to this, we performed B3LYP-D3 periodic calculations as implemented in CRYSTAL17.

Ultrabroadband Long-Wavelength Near-Infrared MgIn2O4:Ni2+ Phosphor Synthesized via Sol-gel Combustion Method as a Light Source for Night Vision Imaging, Nonvisual Detection, and Anticounterfeiting Display.

Long-wavelength near-infrared (LWNIR) imaging technology has exciting application potential across various fields due to its ability of deeper penetration and unique properties related to its emission wavelength, when compared to short-wavelength near-infrared imaging. However, the limited availability of materials for LWNIR light sources, due to the lack of suitable host materials that constitute luminescence centers, has been a major challenge and technical obstacle in realizing such applications. Here, we developed MgIn2O4:Ni2+ phosphors with an antispinel structure and LWNIR luminescence properties through a sol-gel combustion method. Under excitation at 365 nm, its emission wavelength covers the range of 1000-2000 nm, with a peak emission at approximately 1520 nm, a full width at half-maximum of ∼340 nm, and an optimized photoluminescence quantum yield of ∼21.22%, when an optimal Ni2+ doping content of 1 mol % was used. Studies on the crystal structure of MgIn2O4 have shown that Ni2+ ions preferentially replace the lattice position occupied by Mg2+ ions in the [MgO6] octahedrons, which provides a crystal field microenvironment of weak strength to the Ni2+ luminescence centers and promotes their LWNIR emission with a large Stokes shift. A LWNIR pc-LED device was assembled using the optimized MgIn2O4:Ni2+ phosphor and a near-ultraviolet LED chip (@ 365 nm), and its potential applications, including NIR night vision imaging, nonvisual detection, and anticounterfeiting displays, were demonstrated. Our results show that the antispinel MgIn2O4:Ni2+ phosphor prepared by the sol-gel combustion method is a promising LWNIR luminescence material.

Rapid Recovery of Degraded Perovskite Single-Crystal Radiation Detectors via Infrared Healing.

Radiation detectors based on metal halide perovskite (MHP) single crystals (SCs) have exhibited exceptional sensitivity, low detection limit, and remarkable energy resolution. However, the operational stability issue still dramatically impedes their commercialization due to degradation induced by high-energy irradiation and large bias. Here, we propose an innovative infrared healing strategy to restore the devices that have undergone severe damage from both long-term biasing and X-ray irradiation. Compared to the slow and inefficient intrinsic self-healing process of MHPs, the infrared healing method demonstrates the capacity to achieve rapid recovery of the detection performance of the degraded devices within just 1 h. We reveal that the healing mechanism is mainly related to the reduction of the ion-migration activation energy in MHP SCs under infrared illumination, which promotes the back diffusion of the displaced ions to their original lattice positions and remedies defects. Finally, the healing effect is further confirmed through the gamma-ray spectroscopy acquisition with degraded MHP SCs, whose energy resolution at 59.5 keV of 241Am source is improved from 36% to 12% following infrared illumination. These results present infrared healing as a simple and economic method to extend the service life of MHP SC-based detectors.

Microscopic damage in eutectic SnPb alloy: First-principles calculations and experiments

This study aims to comprehensively elucidate the microscopic origins of damage in eutectic SnPb alloy through atomic-scale investigations, a crucial endeavor for enhancing the alloy’s properties and furthering the development of Pb-free solders. First-principles calculations based on density functional theory (DFT) were employed to examine the mechanical constants and defect formation energies of the Pb phase, the β-Sn phase, and potential Sn/Pb eutectic phases in the SnPb alloy. The Voigt-Reuss-Hill approximation was utilized to derive the mechanical parameters of the elastically stable structure in SnPb alloy, facilitating the prediction of its mechanical properties. The defect formation energy calculations revealed a higher difficulty in forming vacancy defects in the β-Sn phase compared to the Pb phase. This discrepancy can be attributed to the stronger interactions between Sn atoms, resulting in the formation of more stable Sn-Sn bonds, thereby impeding vacancy generation in the β-Sn phase. Furthermore, the Pb phase exhibited a tendency for Sn atoms to occupy octahedral interstitial sites, whereas in the β-Sn phase, Pb atoms tended to displace neighboring Sn atoms along the [110] orientation into adjacent interstitial sites and occupy their lattice positions. Experimental observations complemented these calculation findings, demonstrating significant Sn element presence, up to 27.22 at%, in the Pb-rich phase, with notable microvoid damage primarily concentrated within this region. This observation aligns with the conclusions drawn from first-principles calculations and unveils the microscopic origins of damage in eutectic SnPb alloys.

First principles study on the electronic structure and optical properties of Janus WSeTe with defects and strains

A Janus monolayer can be described as a two-dimensional material with distinct anions on either side of each layer. Two of these distinct chalcogen atoms are situated in the mirror-symmetric lattice positions of the transition metal atoms and are referred to as Janus transition metal dichalcogenides (TMDs). This material breaks the out-of-plane mirror symmetry and thus has excellent properties not found in conventional TMDs. However, during material synthesis, it can generate a number of defects that can substantially alter its properties. Therefore, in this article, the changes in the electronic structure and optical properties of Janus WSeTe when generating single vacancy defects, double vacancy defects and antisite defects have been investigated using first principles study. Assess the stability of the material through computations of its phonon spectrum, AIMD simulation and defect formation energy. Analyse its bandstructure, projected density of states, and optical absorption coefficient to present the change in its properties. The results show that the easiest and most stable form of defect is the substitution of Se atom for Te atom. These defect types change the bandgap value in different ways in Janus WSeTe, which further changes the peak optical absorption coefficient. The lattice constants undergo alterations during the defect generation process. For this purpose, we also investigated the changes in the properties of Janus WSeTe and its defects when subjected to biaxial tensile and compressive strains ranging from −9% to 9 %. As the tensile and compressive strains increase, a gradual decrease in the band gap value is observed. Our findings may serve as a theoretical basis for experiments in the synthesis of Janus WSeTe and the development of electronic devices using monolayer Janus WSeTe.

Controlled creation of point defects in three-dimensional colloidal crystals.

Crystal defects crucially influence the properties of crystalline materials and have been extensively studied. Even for the simplest type of defect-the point defect-however, basic properties such as their diffusive behavior, and their interactions, remain elusive on the atomic scale. Here, we demonstrate in situ control over the creation of isolated point defects in a three-dimensional (3D) colloidal crystal allowing insight on a single-particle level. Our system consists of thermoresponsive microgel particles embedded in a crystal of nonresponsive colloids. Heating this mixed-particle system triggers the shrinking of the embedded microgels, which then vacate their lattice positions, creating vacancy-interstitial pairs. We use temperature-controlled confocal laser scanning microscopy to verify and visualize the formation of the point defects. In addition, by reswelling the microgels we quantify the local lattice distortion around an interstitial defect. Our experimental model system provides a unique opportunity to shed light on the interplay between point defects, on the mechanisms of their diffusion, on their interactions, and on collective dynamics.

A Review on hydrogen embrittlement behavior of steel structures and measurement methods

Hydrogen can be found within metals under a variety of industrial and environmental conditions. Hydrogen-metal interactions can take place through hydrogen embrittlement, hydrogen sulfide corrosion, or hydrogen absorption. Steel and other metals that are exposed to hydrogen may experience a difficulty known as hydrogen embrittlement that affects their mechanical properties. The material's ductility and toughness may be reduced as a result of this phenomena, it also increasing the risk of brittle fracture. In steel, atomic hydrogen mainly diffuses into the microstructure of the steel, causing hydrogen embrittlement. Localized weakening of the bonds between the metal atoms might result from hydrogen atoms occupying interstitial positions in the metal lattice. Especially when under stress, this may lead to a more susceptible to fracture and cracking. Concerns with hydrogen embrittlement arise in sectors like aerospace and oil and gas that use high-strength steels. If not appropriately handled, it may result in catastrophic failures. Use of hydrogen-resistant alloys, appropriate heat treatments, and protection from conditions that promote hydrogen uptake are examples of preventive measures. This literature review paper covers the definition of hydrogen embrittlement (HE), mechanisms causing HE, measurement of hydrogen concentration and preventive measures that restrict hydrogen diffusion to the steel.

Efficiency of Cr3+ → Cr4+ conversion in YSAG:Cr ceramics

In this study, we investigated the influence of the position and quantitative content of scandium in YSAG:Cr on the efficiency of chromium cation valence conversion. YSAG:Cr ceramic powders were synthesized using the chemical precipitation method. It was determined that the microstructure of ceramics and the luminescent properties of YSAG:Cr4+ depend on the predominant position of scandium, whether it replaces octahedral or dodecahedral positions in the garnet crystal lattice. An increase in Scdod content contributed to a decrease in grain size and a shift of the emission peak of Cr4+ ions towards the short-wavelength region. Conversely, an increase in Scoct content led to an increase in grain size and a shift of the maximum of the luminescent band towards the long-wavelength region. It was found that increasing the quantitative content of scandium in the octahedral position in the garnet structure by up to 50 % enhances the efficiency of the conversion of Cr3+ to Cr4+, while an increase in the proportion of Scdod resulted in a decrease in conversion efficiency.

Structure, vacancy, and physical properties of non-stoichiometric MnWO4 ceramics

Non-stoichiometric ceramic samples of Mn0.97WO4 and MnW0.97O4 were prepared by a solid-state reaction to study the effects of vacancies at different lattice positions on the structure and properties of MnWO4 materials caused by non-stoichiometric. Positron annihilation technology was introduced to study the vacancy characteristics of the MnWO4, Mn0.97WO4, and MnW0.97O4 ceramics. The results indicated that non-stoichiometric did not affect the monoclinic lattice structure of any of the MnWO4 samples, and had no obvious effect on the lattice parameters of the samples. The analysis of positron annihilation lifetime spectroscopy showed that W vacancies were the main defects in MnW0.97O4 samples, and Mn vacancies were favored in Mn0.97WO4 samples, the vacancies concentration for non-stoichiometric MnWO4 samples was higher than that of stoichiometric MnWO4. It was observed that the magnetization and transition temperatures of the non-stoichiometric MnWO4 system were increased, and the temperature range in which AF2 phase existed was enlarged. This study demonstrated that non-stoichiometric could enhance the magnetic properties of MnWO4, the effect of Mn vacancy on the properties of MnWO4 is higher than that of W vacancy. The intimate correlation between the vacancy defects and magnetic properties provides us strong evidence that the magnetic properties of MnWO4 can be enhanced by regulating vacancy defects.

Suppressed Lone Pair Electrons Explain Unconventional Rise of Lattice Thermal Conductivity in Defective Crystalline Solids.

Manipulating thermal properties of materials can be interpreted as the control of how vibrations of atoms (known as phonons) scatter in a crystal lattice. Compared to a perfect crystal, crystalline solids with defects are expected to have shorter phonon mean free paths caused by point defect scattering, leading to lower lattice thermal conductivities than those without defects. While this is true in many cases, alloying can increase the phonon mean free path in the Cd-doped AgSnSbSe3 system to increase the lattice thermal conductivity from 0.65 to 1.05Wm-1K-1 by replacing 18% of the Sb sites with Cd. It is found that the presence of lone pair electrons leads to the off-centering of cations from the centrosymmetric position of a cubic lattice. X-ray pair distribution function analysis reveals that this structural distortion is relieved when the electronic configuration of the dopant element cannot produce lone pair electrons. Furthermore, a decrease in the Grüneisen parameter with doping is experimentally confirmed, establishing a relationship between the stereochemical activity of lone pair electrons and the lattice anharmonicity. The observed "harmonic" behavior with doping suggests that lone pair electrons must be preserved to effectively suppress phonon transport in these systems.

Ferromagnetism with above-room-temperature Curie temperature in Fe-doped β-Ga2O3 studied by first-principles calculations

Induced by the spin-polarized double-exchange interaction between the 3d orbitals of Fe atoms and O-2p orbitals near the O/Ga vacancy complexes, the origin of magnetism in β-Ga2O3 is investigated by using geometry optimization and energy calculation based on the first-principles generalized gradient approximation Hubbard + U method of density-functional theory. The results show that the formation energy of Fe2+ in the β-Ga2O3 matrix is lower than that of Fe3+, and the system is more stable when the Ga or O vacancies (VGa or VO) are adjacent to the Fe lattice position. It is found that the β-Ga31Fe2+/3+O47 and β-Ga30Fe2+/3+O48 systems all exhibit ferromagnetism with above-room-temperature Curie temperature. β-Ga30Fe2+/3+O48 (i.e., with Fe2+/3+ and VGa) has more spin-polarized O atoms in the same direction. The magnetism originates from the double-exchange interaction of the coupling and hybridization of the Fe-3d state of Fe3+ and the O-2p state, which increases the magnetic moment of the β-Ga30Fe3+O48 system. This study provides a theoretical reference for designing and preparing new β-Ga2O3-based dilute magnetic semiconductors and related spintronic and optoelectronic devices.

A promising route for developing green phosphor with mechanoluminescence and long persistent luminescence in Sr2Ga2GeO7: Tb3+

Mechanoluminescence (ML) materials featuring photon emission under mechanical stimulation have attracted the attention of scientists doing researches on structure monitoring, stress sensing, anti-counterfeiting and imaging. In this study, a novel series of ML green phosphors Sr2-xGa2GeO7: xTb3+ (0 ≤ x ≤ 0.05) have been synthesized by a high-temperature solid-state method for the first time. Their crystal structure, optical properties and attenuation profiles have been investigated. X-ray diffraction (XRD) analysis reveals that the sample is tetragonal with a space group of P4‾ 21m, and Tb3+ partially replaces the lattice position of Sr2+ in the Sr2Ga2GeO7 crystals. The green ML emission mechanism is attributable to the typical 5D4 → 7F5 transition of Tb3+ ions, similar to persistent luminescence (LPL) and the photoluminescence (PL). To better understand the mechanism of potential LPL and ML in this system, the trap regulation is comprehensively investigated by a series of thermoluminescence (TL) measurements.

Regulated Hydrated Eutectic Electrolyte Enhancing Interfacial Chemical Stability for Highly Reversible Aqueous Aluminum‐Ion Battery with a Wide Temperature Range of −20 to 60 °C

AbstractThe development of aqueous aluminum‐ion batteries (AAIBs) is impeded by pronounced side reactions and hydrogen evolution reaction (HER). Here, an eutectic electrolyte named HEE30 (with an optimal molar ratio of 1:8:1:30 for Al(OTf)3, glycerol (Gly), sodium beta‐glycerophosphate pentahydrate (SG), and H2O) to significantly enhance the reversibility of AAIBs across a wide temperature range from −20 to 60 °C is designed. The combination of molecular dynamics simulations and operando synchrotron Fourier‐transform infrared spectroscopy reveals that the unique eutectic network significantly enhances the hydrogen bonding between Gly and H2O, reduces the solvation interaction of Al3+ with active H2O, thereby lowering the freezing point, extending electrochemical windows and suppressing HER. The X‐ray photoelectron spectroscopy (XPS) and X‐ray diffraction (XRD) tests demonstrate that HEE30 is capable of forming a solid electrolyte interface layer consisting of organic and inorganic components, which effectively inhibits corrosion. Additionally, operando synchrotron XRD and ex situ XPS are employed to investigate the changes in lattice peak width and position of the Prussian white cathode, as well as the reversible storage mechanism during cycling This quantitative design offer immediate advantages for the rational development of low‐cost and safe energy storage batteries, specifically tailored for wide‐temperature operation and durable cycling.

Prediction of highly stable 2D carbon allotropes based on azulenoid kekulene

Despite enormous interest in two-dimensional (2D) carbon allotropes, discovering stable 2D carbon structures with practically useful electronic properties presents a significant challenge. Computational modeling in this work shows that fusing azulene-derived macrocycles – azulenoid kekulenes (AK) – into graphene leads to the most stable 2D carbon allotropes reported to date, excluding graphene. Density functional theory predicts that placing the AK units in appropriate relative positions in the graphene lattice opens the 0.54 eV electronic bandgap and leads to the appearance of the remarkable 0.80 eV secondary gap between conduction bands – a feature that is rare in 2D carbon allotropes but is known to enhance light absorption and emission in 3D semiconductors. Among porous AK structures, one material stands out as a stable narrow-multigap (0.36 and 0.56 eV) semiconductor with light charge carriers (me = 0.17 m0, mh = 0.19 m0), whereas its boron nitride analog is a wide-multigap (1.51 and 0.82 eV) semiconductor with light carriers (me = 0.39 m0, mh = 0.32 m0). The multigap engineering strategy proposed here can be applied to other carbon nanostructures creating novel 2D materials for electronic and optoelectronic applications.

Investigating the mechanism of formation of Ca-rich Ca[sbnd]Yb apatite that forms from the Yb-silicate–CMAS reaction at 1300°C

The formation mechanism and structure of Ca-rich CaYb apatite, which forms from the corrosion of Yb-silicate based coatings with CMAS at 1300°C in air for 48 h was investigated. X-ray photoelectron spectroscopy (XPS) was used to determine the bond type and oxidation states of the apatite. XPS data showed that the Si2p peaks are related to silicates, while the Ca2p and Yb4d are linked to apatite structures. The mechanism of growth for the apatite is proposed using the Wagner-Hauffe oxidation principle and the Kröger-Vink notations. The formation mechanism of the apatite-structure reaction phase is by substitutional diffusion, which is governed by the movement (formation and destruction) of point defects within the Yb2O3 lattice, particularly oxygen vacancies and electron holes. When Ca2+ substitutes Yb3+ in its lattice position, this results in the formation of anionic vacancies, which leads to more Ca2+ diffusion. The diffusion process continues until vacancies can no longer form to achieve electroneutrality, which leads to the newly formed Yb–Ca–Si being saturated with cations. Thus, based on this investigation, it is assumed that a CaYb silicate oxyapatite coatings can suppress the vacancy formation mechanism by containing high Ca and Si content which can thus decrease the ionic diffusion from CMAS melt into the EBC lattice. This can be the premises of a more CMAS-resistant coating family.