Intermetallic Phases Research Articles

Role of solute elements in Mg-Mg2Ni hydrogen storage alloys: A first-principles calculation study

The effects of various alloying elements on the performance of Mg-Mg2Ni hydrogen storage alloys were investigated by performing first-principles density functional theory calculations. We examined the important characteristics of hydrogen storage alloys by considering both Mg-based solid solution and Mg2Ni-based intermetallic compound phases, where the hydride forms are MgH2 and Mg2NiH4, respectively. In particular, qualitatively valid information for predicting changes in plateau pressures in the pressure-composition-temperature (PCT) curve was provided by calculating changes in the energy of related hydrogenation reactions. The effects of alloying elements on volume changes due to hydrogenation reactions were also obtained to provide additional criteria for the practical use of hydrogen storage alloys. For the Mg2Ni-based intermetallic compound, we examined the site preference of each alloying element, considering the designated stoichiometry of the base alloy. Based on the revealed site preferences, the effects of various possible alloying elements on the properties of Mg2Ni-based hydrides were also examined. Electronic structure analyses were further conducted to elucidate the detailed mechanisms underlying the role of the additional solute elements.

CALPHAD modeling of [formula omitted]- carbide dual ordering in Fe-Al-C ternary alloys

A novel four-sublattice model for the κ phase, denoted as (Fe, Al)3(Fe, Al)1(C, Va)1(C, Va)3 was proposed to improve the thermodynamic prediction, such as equilibrium composition, phase stability of κ-carbide in Fe-Al-C system. The sublattice model explains the transformation from the disordered FCC solid solution to the ordered κ-carbide via concurrent ordering of substitutional and interstitial atoms. The dual ordering model can restrict the irregular contribution of configurational entropy arising at 20 at% C composition, which is an issue with the existing thermodynamic databases. For the CALPHAD assessment, κ-carbide was considered as a single, individual phase that is in equilibrium with the liquid, austenite (γ), ferrite (α) or other intermetallic and carbide phases in the Fe-Al-C system. The formation energy calculated from density functional theory (DFT) showed that Fe3Al–L12 phase is energetically more favorable than the Fe3AlC–E21 phase, and C atoms in sublattice IV are not energetically favorable at all. The assessed parameters provided better accuracy than the existing database in the calculations of isothermal sections, liquidus projection, invariant reactions, and low-temperature phase compositions. The model is highly suitable for the low temperature (<800 °C) phase predictions. Thus, the improved Fe-Al-C model lays the foundation for the thermodynamic and kinetic studies of κ-carbide for designing new Fe-Mn-Al-C alloys and optimizing the heat treatment processes.

Characteristics of cast Ti53.3-xNb10Zr10Ni10Co10Fe6.7Bx compositionally complex alloys

In the current investigation, elemental boron was added to form a series of Ti53.3-xNb10Zr10Ni10Co10Fe6.7Bx Compositionally Complex Alloys (CCAs). Alloying was done via vacuum arc melting in amounts of 0.0, 5.3, and 10.6 at.%. From the thermodynamic parameters, adding B to the base alloy increased the system’s entropy. The microstructure of the prepared CCAs was characterized using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction (XRD). The mechanical properties of CCAs as related to microstructure were assessed. According to XRD results, B-based intermetallic phases were obtained in the prepared CCAs, which were binary as Ti3B4 and ZrB2 and ternary as FeNbB and Nb3Co4B7. These intermetallic phases notably provided strengthening effects to the B-added alloys. Ti48Nb10Zr10Ni10Co10Fe6.7B5.3 CCA showed the most homogenous microstructure obtained by the arc melting process. Adding B increased Young’s modulus from 141 GPa (without B) to 195 GPa and 260 GPa with 5.3 and 10.6 at.%B, respectively. Hardness also increased from 502 to 606 HV with 5.3 at.% B and to 648 HV with 10.6 at.%B. Accordingly, the wear resistance increased with B addition where 10.6 at.%B sample showed the lowest wear rate among the other conditions. However, 5.3 at.% B was nominated as the optimum addition amount due to its notable microstructure homogeneity.

Multiresponse optimization applied to friction-stir processing to enhance wear and corrosion performance in Al–Si alloys

In this study, friction stir processing (FSP) parameters were optimized using the response surface method (RSM) to enhance hardness, reduce the friction coefficient and minimize the corrosion rate in cast Al12Si and Al14Si alloys. The FSP tool, made of AISI H13 tool steel, features a concave shoulder and conical pin designed to induce severe plastic deformation. Microstructural analysis was performed via optical microscopy and SEM–EDS, and the particle size and distribution were assessed via ImageJ software. Microhardness profiles were measured across the Nugget, TMAZ, HAZ, and substrate zones. The corrosion resistance was evaluated using an AutoLab potentiostat/galvanostat following ASTM G59-97 standards, whereas the wear performance was assessed using a reciprocating linear tribometer (ASTM G133). FSP led to the fragmentation and uniform distribution of silicon and Fe-rich intermetallic phases within the aluminum matrix. The multiresponse optimization identified the optimal FSP parameters for Al12Si alloys at a tool rotation speed of 1100 rpm and a travel speed of 16 mm/min. Under these conditions, the Al12Si samples presented the highest microhardness (93 Hv), significant fragmentation of silicon particles (2.82 μm) and Fe-rich intermetallic phases (2.07 μm), reduced friction coefficient (0.60) and low corrosion rate (1.28 × 10⁻4 mm/y). The proposed model offers a reliable method to optimize FSP, leading to aluminum surfaces with superior microstructure, hardness, wear resistance and corrosion resistance.

Tribological Properties of SPS Reactive Sintered Al/MoS2 Composites

In search of opportunities to improve mechanical properties and abrasion resistance, composites based on aluminum reinforced with MoS2 particles were produced. The authors’ previous research indicated the possibility of obtaining hard dispersion precipitates of the Al12Mo intermetallic phase as a result of the reaction of the composite components at a temperature exceeding 550 °C during the SPS (Spark Plasma Sintering) process. This work focused on optimizing the SPS consolidation process and assessing the microstructure and mechanical properties of the obtained materials. A series of experiments proved that by increasing the amount of the strengthening phase and increasing the process temperature, a significant amount of Al12Mo and Al5Mo strengthening phases is produced. Exceptionally good dispersion of reinforcing particles and the presence of layered MoS2 crystals, while ensuring optimal parameters of the synthesis process, lead to a change in friction mechanisms and improved abrasion resistance through an approximately 30-fold decrease in the wear factor.

Microstructural and tribological properties of multilayered coatings developed through heat treatment on the surface of CP-Ti

It is well known that applying NiTi intermetallic coatings on the surface of different alloys can improve their tribological behavior. In this paper, various intermetallic phases of Ni3Ti, NiTi, and NiTi2 and a Ti-rich pearlite-like eutectoid structure were in situ synthesized on the surface of commercially pure (CP) titanium grade 2. Nickel electroplating was performed on titanium samples followed by heat treatment at a temperature of 800 °C for various times up to 8 h. The formation of various phases and structures along the depth were studied using SEM, EDS and XRD. Heat treatment at a temperature of 800 °C for 4 h resulted in the formation of a multi-layered composite of Ni3Ti, NiTi, and NiTi2 intermetallic films with a thickness of 5, 9, and 2 μm, respectively. A nickel diffusion layer (NDL) with a pearlitic structure containing nanolayers of αTi-NiTi2 was also formed beneath the NiTi2 layer even after 30 min of heating. Among the different layers formed on the surface of CP-Ti, the titanium-rich NiTi (51–52 at.% Ti) showed the highest hardness of more than 400 HV. Sliding wear tests were performed under a normal load of 10 N and the surfaces of wear tracks were studied using SEM. The results showed higher wear resistance of all intermetallic layers and NDL than the titanium substrate, with the highest wear resistance for Ni3Ti top layer.

Unravelling crack tip damage mechanisms: In-situ tensile assessment of Al-6Zn-2.1 Mg-2Cu alloy strengthened by Ti, Zr, and Sc micro-alloying

This study investigates the effect of micro-alloying elements (Ti, Zr and Sc) on the crack tip damage behaviour of cast Al-6Zn-2.1Mg-2Cu-X alloys to understand the effect of grain boundary interfaces, matrix, intermetallics and dispersoids on deformation and fracture behaviour. Notched tensile specimens were prepared and subjected to in-situ tensile deformation under FESEM to investigate the crack initiation, propagation, and eventual failure processes under uniaxial tensile loading. The experimental results reveal that fracture in the four Al-6Zn-2.1Mg-2Cu-X alloys is quasi-brittle due to strain accumulation and cleavage fracture mechanisms. The crack mainly initiates from the grain boundary lath S-Al2CuMg and η-MgZn2 intermetallic phases. Adding 0.25 % Sc forms small coherent Al3(Sc, Zr) dispersoids, increasing crack resistance. The ductility of the matrix is due to void nucleation, crack meandering, and crack tip-blunting phenomena. At high additions of microalloying elements (1 wt%), large Al3(Zr, Ti) intermetallics form and agglomerate, contributing to premature fracture. These findings from materials characterization and in-situ tensile testing indicate potential methods to enhance the fracture toughness of Al-6Zn-2.1Mg-2Cu alloys with additions of Zr, Ti, and Sc.

Using dynamic resistance to predict electrode surface degradation in resistance spot welding of 5182 aluminum alloy

AbstractIn this study, the correlation between dynamic resistance during the first 10 ms of welding time and the electrode surface condition in resistance spot welding of 5182 aluminum alloy has been investigated. The electrode surface rapidly degrades due to contamination and morphological changes, adversely affecting the weld spot surface. The accumulation of Cu-Al intermetallic phases on the electrode surface alters its roughness, leading to variations in dynamic resistance. By analyzing this correlation, optimal electrode milling intervals were identified to extend electrode life. This work focused on detecting crater formation on the electrode surface through dynamic resistance monitoring. The results indicate that resistance measurements provide a reliable approach for evaluating electrode wear, optimizing maintenance schedules, and reducing material removal during milling.

Alkaline etching of diffusion zinc coatings NiZn and CoZn as promising electrocatalysts for hydrogen evolution reaction

Coatings based on NiZn and CoZn alloys were obtained by combining electrodeposition and diffusion galvanizing methods. The coatings are homogeneous and uniform, the zinc concentration is between 85.0 to 89.5 at. %, and consist of intermetallic phases of NiZn and CoZn, mainly γ-Ni2Zn11 and γ2-CoZn13. Alkaline etching of coatings is accompanied by selective dissolution of zinc, and the rate of dissolution of coatings increases with time. This dealloying is accompanied by a change in the morphology of the coatings - cracks, pits, and pores of considerable depth are formed. These defects contribute to the formation of galvanic coupling between the coating and the substrate, which leads to an increase in the dissolution rate. The electrochemical behavior of coatings after alkaline etching in the cathodic hydrogen evolution reaction was studied. The cathodic current of hydrogen evolution on coatings alkaline etching increases by 1.5 to 3 times compared to coatings before etching. This effect is greater on Ni-based coatings. Diffusion galva­nizing followed by dealloying is a promising method for creating electrode materials for alkaline electrolysis with hydrogen evolution.

Impact of Surface Microstructure and Properties of Aluminum Electrodes on the Plating/Stripping Behavior of Aluminum-Based Batteries Using Imidazolium-Based Electrolyte.

The 99.99% Al used for negative Al electrodes in aluminum-based battery studies is expensive. This is primarily due to the complex challenges associated with fabricating 99.99% Al, particularly the removal of Fe impurities from Al melts. Despite the importance of this issue for the future commercialization of Al-based batteries, it has been largely overlooked. This work accordingly studied the plating/stripping behavior of Al containing 1 wt % iron (Al 1% Fe) as an alternative electrode using conventional ([EMIm]Cl and AlCl3) electrolyte. Simultaneously, the impact of the surface microstructure of Al 1% Fe on the plating/stripping behavior was examined. The results indicate that the difference in the plating/stripping cycling of Al 1% Fe alloys and 99.99% Al is negligible. Thus, Al 1% Fe negative electrodes could serve as an efficient and commercially viable alternative to 99.99% Al for plating/stripping in Al-based batteries. This is an essential finding because facile and commercial fabrication of Al 1% Fe electrodes is absolutely feasible. The results are further discussed in terms of the impact of the Al surface microstructure (i.e., grain size, defect density, grain boundary distribution, crystal orientation, and intermetallic phases) on plating/stripping behavior. Moreover, this study provides insights into how the interphase layer formed on Al electrodes influences plating/stripping behavior.

A low copper content alloy Al(1-x)Cux, x≤0.1: A joint computational and experimental study

Atomistic simulation of Al1-xCux (x ≤ 0.1) alloy is performed and the mechanical properties are calculated within the framework of the density functional theory (DFT) by using of the virtual crystal approximation (VCA). The elastic matrix is calculated within the DFT using the CASTEP code and the dependences of Young's, shear and bulk moduli, Vickers hardness, Poisson's ratio, plasticity coefficient and anisotropy indices on the amount of copper are obtained. Al0.9Cu0.1 alloy was synthesized by spark plasma sintering (SPS) method. As a result, the aluminum and intermetallic CuAl2 phases were identified in the obtained sample by X-ray diffraction patterns. The microstructure (SEM) and Vickers microhardness of the sample were studied. The results of the work compensate for the lack of data for the Al-Cu alloys with a low copper content.

Non‐Destructive and Mechanical Characterization of the Bond Quality of Co‐Extruded Titanium‐Aluminum Profiles

The transportation industry aims to improve energy efficiency and reduce CO2 emissions, with a focus on reducing vehicle mass. A key method involves advanced lightweight construction techniques using materials like aluminum alloys. Research is concentrated on developing processes to combine different materials into reinforced hybrid components, such as aluminum and titanium. This study focuses on the lateral angular co‐extrusion (LACE) process to produce hybrid hollow profiles of EN AW‐6082 and Ti6Al4V, investigating the impact of the thermomechanical processing during extrusion and heat treatment (HT) on the resulting bond quality and material properties. Various HT routes are tested to see their impact on intermetallic phase formation, longitudinal weld seams, and bonding strength. Mechanical testing evaluates the tensile strength of the joining zone, while nondestructive ultrasonic testing (UT) assesses joining zone integrity and poor bonding detection. Results indicate that HT parameters significantly influence the bond quality and mechanical properties of hybrid profiles. UT data shows a strong correlation with tensile strength and intermetallic phase growth, providing a nondestructive way to evaluate bond quality. This study highlights the potential of LACE processes and optimized HT strategies to improve the performance and reliability of aluminum–titanium hybrid components.

Properties of Al0.5CoCrFeNi2Ti High-Entropy Alloy System: From Gas-Atomized Powders to Atmospheric Plasma-Sprayed Coatings

AbstractThe performance of the Al0.5CoCrFeNi2Ti HEA atmospheric plasma-sprayed coating was extended from characterizing the properties of its powder prepared via the gas atomization method. It was observed that the gas-atomized HEA powders possessed a solid solution BCC phase, while a major phase transformation to a FCC-L21 intermetallic phase occurred during the annealing process. The formation of the intermetallic phase resulted in an increase in average hardness from 6.28 to 7.64 GPa after annealing at 900 °C for 1 h. Afterward, HEA powders were applied in the atmospheric plasma spray technology. The phase constitution of Al0.5CoCrFeNi2Ti HEA coatings was investigated by varying powder size and applied current. It was observed that the smaller powder sizes prone to oxidation, whereas higher applied current facilitated the phase transformation from BCC to FCC phase. The nanoindentation test indicated distinct average microhardness values for the interlamellar oxide region, BCC unmelted particle and FCC phase lamellar region, which was measured at 12.35, 8.68 and 5.97 GPa, respectively. As a result, the adjustability of coating hardness was achieved by manipulating the relative phase ratio.

Production and Forming of Deposition‐Welded Hybrid Multimaterial Shafts

The combination of several materials in one component can contribute to increased performance. Herein, three types of hybrid components are manufactured using two cladding processes and one joining process. The resulting workpieces are then formed and tested to determine the potential of the different material combinations. Two types of workpieces are produced to investigate multilayer claddings made of different materials, which serve to positively adjust the residual stress. The workpieces are tested using microstructural images and hardness measurements to characterize the microstructure and properties of the intermediate layers. In addition, residual stress measurements are carried out to determine the residual stress ratios. Compressive residual stresses are present in the subsurface of the welded and subsequently formed layer, which will improve the service life in case of rolling load conditions. The third type of workpiece is a combination of aluminum alloy and steel with a cladding layer that combines the performance of the cladding material in the bearing seat with the weight reduction of the aluminum alloy. Scanning Electron Microscopy (SEM) measurements are used to determine whether the application of the cladding has an influence on the intermetallic phase seam in the joining zone of aluminum alloy and steel.

Evaluation of Structural Transition Joints Cu-Al-AlMg3 Used in Galvanizer Hangers

The paper deals with the evaluation of the quality of Cu-Al-AlMg3 structural transition joints (STJ) made by explosion welding proposed for the renovation of galvanizer hangers. The three-layer joint consisted of electrolytic copper with a thickness of 25 mm, 2 mm of aluminium represented by the AW1050 alloy, and 25 mm of the EN AW 575 aluminium alloy. Light microscopy analysis confirmed the wavy pattern of both interfaces of the welded joint and significant plastic deformation in close proximity to the waves. Microhardness measurement revealed a partial strain hardening of the AW5754 copper-aluminium alloy near the interface and a significant increase in microhardness in the vortex zone of waves, reaching a value of up to 863 HV 0.025. Microcracks were also observed in these places. The intermetallic phase Al2Cu was identified in the vortex zones by XRD analysis. As a continuous layer of intermetallic phase was not observed in the interface of the welded joint, it is possible to consider the used welding parameters as appropriate. A semi-quantitative EDX analysis revealed a diversity of chemical composition in the vortex zones, which does not correspond to the phase composition based on the equilibrium binary Al-Cu diagram due to non-equilibrium conditions in the formation of the welded joint interface. The bond strength of three-layer welded joint evaluated by the strength test ranged from 151 to 171 MPa, which represented approximately a two-fold increase in comparison to the ultimate tensile strength of alloy AW1050, while the failure occurred in all samples at the AW1050-AW5754 alloy interface.

The role of surface substitution in the atomic disorder-to-order phase transition in multi-component core–shell structures

Intermetallic phases with atomic ordering are highly active and stable in catalysts. However, understanding the atomistic mechanisms of disorder-to-order phase transition, particularly in multi-component systems, remains challenging. Here, we investigate the atom diffusion and phase transition within Pd@Pt-Co cubic nanoparticles during annealing, using in-situ electron microscopy and ex-situ atomic resolution element analysis. We reveal that initial outward diffusing Pd partially substitutes Pt, forming a (Pt, Pd)-Co ternary system in the surface region, enabling the phase transition at a low temperature of 400 °C, followed by shape-preserved inward propagation of the ordered phase. At higher temperatures, excessive interdiffusion across the interface changes the stoichiometric ratio, diminishing the atomic ordering, leading to obvious change in morphology. Calculations indicate that the Pd-substitute in (Pt, Pd)-Co system leads to a significantly lower phase transition temperature compared to that of Pt-Co alloy and thus a lower activation energy for atomic diffusion. These insights into atomistic behavior are crucial for future design of multi-component systems.

Tailoring mechanical properties of Mo-SiC composites through controlled phase formation during reactive spark plasma sintering

The present study investigates the sintering behavior of Mo-xSiC reactive composites (x= 10–40 vol%) using reactive spark plasma sintering (RSPS) at 1700°C for 5 min. The microstructure, phase formation, and mechanical properties of the fabricated composites were evaluated. X-ray diffraction (XRD) analysis reveals the formation of various compounds, including Mo2C, Mo3Si, and Mo4.8Si3C0.6, which increase in intensity with increasing SiC content. It was found that composites with 10 vol% and 15 vol% SiC still contained unreacted Mo phase, whereas larger amounts of SiC resulted in no remaining Mo. Conversely, unreacted SiC particles were detected in all composites. Field-emission scanning electron microscopy (FESEM) and energy-dispersive spectroscopy (EDS) analysis confirm the presence of multiple phases. The flexural strength of the composites exhibits complex relationships with SiC content, with Mo-10 vol% SiC and Mo-15 vol% SiC composites showing superior strength (585±32 MPa and 618±21 MPa) due to the presence of unreacted Mo phase. The strength decreased with increasing SiC content, likely due to the formation of brittle intermetallic phases. Hardness increased with SiC content, with a significant improvement in Mo-20 vol% SiC composite (12.88 ± 0.21 GPa), but decreased thereafter. Fracture toughness followed a different trend, decreasing with increasing SiC content due to the elimination of ductile Mo phase and the formation of brittle phases. Therefore Mo-10 vol% SiC and Mo-15 vol% SiC composites exhibited the highest fracture toughness values of 8.34±0.68 MPa.m1/2 and 7.99±0.37 MPa.m1/2, respectively.

Investigation of NiAl Intermetallic Compound Formation in Layered Ni–Al‐Thin Film Systems by Grazing Incidence X‐Ray Absorption Spectroscopy

NiAl bi‐ and trilayers are prepared by alternating evaporation of aluminum and nickel on float glass substrates under high vacuum, with individual layer thicknesses between 20 and 100 nm. The samples are subjected to an annealing procedure to temperatures of up to 300 °C in vacuum, and the structural changes induced by the heat treatments are followed by in situ grazing incidence X‐ray absorption spectroscopy experiments at the Ni K‐edge. The results show that the elemental metallic deposits are stable up to 180 °C, while a slow formation of the intermetallic NiAl compound occurs at temperatures above 200 °C. No additional reaction intermediates are detected. Linear combination fits employing spectra of face‐centered metallic Ni and body‐centered NiAl as references allow to quantify the contributions of the respective phases as a function of the temperature and the depth in the multilayer. In general, an increase of the phase fraction of the intermetallic NiAl phase is detected. While the deposited elemental metals cannot completely be transformed into this intermetallic compound for the Al–Ni bilayer system even after prolonged annealing at 240 °C, the analysis of the spectra of the Al–Ni–Al trilayer suggests almost complete conversion to NiAl with body‐centered‐cubic structure.

Coupling CALPHAD Method and Entropy-Driven Design for the Development of an Advanced Lightweight High-Temperature Al-Ti-Ta Alloy.

In this study, a new lightweight Al-Ti-Ta alloy was developed through a synergistic approach, combining CALPHAD methodology and entropy-driven design. Following compositional optimization, the Al87.5Ti6.25Ta6.25 (at.%) alloy was fabricated and isothermally heat-treated at 475 °C for 24 h to attain equilibrium. X-ray diffraction (XRD), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) analyses revealed a dual-phase microstructure comprising a 50 vol.% FCC matrix enriched in Al and 50 vol.% Al3(Ti,Ta)-type intermetallic phase (IP). Notably, the FCC phase exhibited a high-melting transition temperature of 660 °C, surpassing conventional Al-Si cast alloys. Phase-specific nanomechanical properties were evaluated using Nanoindentation. Microindentation tests demonstrated exceptional microhardness of approximately 3300 MPa. These results indicate the alloy's superior hardness compared to conventional alloys such as Al-Si (A390), 7075 Al alloy, and CP-Ti, even exceeding Ti-64 alloy at a 15% lower density. The alloy's stability under prolonged heat treatment at 475 °C, reflected by stable phases, microstructure, and mechanical properties, highlights its enhanced thermal stability, which can be attributed to entropy-driven phase stabilization. This study underscores the effectiveness of integrating entropy-driven design strategy with CALPHAD predictions for the accelerated development of advanced Al-based alloys.

Studies on high temperature erosion behavior of HVOF-sprayed (Cr₃C₂-NiCr)Si and WC-Co/NiCrAlY composite coatings

The present study investigates the high temperature erosion behavior of HVOF sprayed composite coatings on T11 steel substrates by studying (Cr₃C₂-NiCr)Si and WC-Co/NiCrAlY coatings. Phase composition, cross sectional microstructure, mechanical properties, and erosion resistance were analyzed by XRD, EDS, SEM and three-dimensional optical profilography. The results demonstrate that the WC-Co/NiCrAlY coating has higher erosion resistance and oxidation stability for all temperatures and impact angles tested. Its enhanced performance in high temperature and erosive conditions is attributable to the formation of stable protective oxides such as Al₂O₃ and Cr₂O₃ and intermetallic phases such as Ni₃Al and Cr₃C₂. The NiCrAlY matrix prevents significant decarburization of WC particles, and hence phase stability and oxidation resistance. The (Cr₃C₂-NiCr)Si coating has higher microhardness due to silicide phases, but is more vulnerable to direct impacts and inferior oxidation resistance. The phase transformations for both coatings are favorable at elevated temperatures which enhances erosion resistance. The WC-Co/NiCrAlY coating is smooth and shallower in erosion craters and is perfectly suited for harsh environments demanding high toughness, impact resistance and oxidation stability. For applications in which high hardness is needed in less severe conditions, the (Cr₃C₂-NiCr)Si coating is more suitable.