Chromium Nitride Research Articles

Femtosecond Laser Texturization on Coated Steel

Surface textures such as laser-induced periodic surface structures (LIPSS) are of great interest to obtain industrial nanopatterns. In this work, plain uncoated 1.2344 steel with and without Chromium Nitride (CrN) and CrN plus diamond-like carbon (DLC) coatings were used in experiments. The laser texturing variables studied were the laser speed (3000–4000 mm/s) and the distance between laser lines (1–10 microns). These structures were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) to obtain an overview of the roughness and to analyze the heights of the obtained structures. A two-dimension fast Fourier transform (2D-FFT) of the SEM images and its characteristic frequencies was used to assess the periodicity of the textured surfaces and thus quantify the far-range order. The speed of laser depth ablation is related to the laser energy density for each coating and textures are qualified using the FFT approach.

Comparing the performance of several tool coatings in turning of commercially pure titanium grade 4

The increasing use of titanium and its alloys in the manufacture of implants results from the simultaneous presence of excellent biocompatibility, relatively low density, high mechanical properties, and corrosion resistance. Unlike the excellent application characteristics, titanium is classified as a difficult-to-machine material. Therefore, one constant challenge for implant manufacturers is to correctly choose turning tools for each application. This work aims to compare the useful life of the uncoated insert with other three types of coatings on carbide tools, titanium aluminum nitride (TiAlN), aluminum chromium nitride (AlCrN), and titanium nitride/titanium carbonitride multilayer coating (TiN + TiCN). Turning experiments were performed using grade 4 commercially pure titanium (typically used in dental implants), testing two cutting speeds for each tool used. The tests were carried out in a CNC rotary head lathe, using cutting fluid in abundance. The results showed that the uncoated insert achieved the shortest life due to its worst properties (lower surface hardness, higher friction coefficient, and lower maximum working temperature), even with its supposedly higher chemical stability with titanium. On the other hand, the tool with the TiN + TiCN multilayer coating obtained the longest tool life among the four tested inserts. The main novelty of this work is that the tool that showed the longest life (TiN + TiCN coating) did not have the best properties among the tested coatings. In fact, it had both the lowest hardness and working temperature. However, this tool has a low coefficient of friction and a multilayer structure coating, which increases its resistance against the wear mechanism that occurred predominantly in this application, which was attrition. Even with the increased cutting speed, this coating also achieved the best result. Therefore, during the machining of titanium, the most important characteristics of the tool are low coefficient of friction and resistance against the pull out of particles.

Corrosion performance of feedstock modified – Additively manufactured stainless steel

Feedstock modified powders were produced by ball-milling commercial 316 L stainless steel powder and 1 wt% additive (Cerium oxide–CeO2, lanthanum (III) nitrate hexahydrate–La(NO3)30.6 H2O and chromium nitride–CrN). Laser-powder bed fusion (L-PBF) was performed on modified feedstock using 180, 200, and 220 W laser power. The influence of additives on microstructure and corrosion performance was investigated on the as-printed and ground/polished conditions of L-PBF-316 L-additive. The corrosion performance was dependent on the type of the additives. The microstructure of the alloys was correlated with the observed corrosion behavior.

Микроструктура и остаточные напряжения многослойных покрытий ZrN/CrN, полученных плазменно-ассистированным вакуумно-дуговым методом

Introduction. The current state of the art in the field of hard coatings application requires the formation of nanostructured compositions using different chemical elements. Modern hard coatings are able to combine different properties such as high hardness, wear resistance, corrosion resistance. At present, coatings formed by layer-by-layer deposition of zirconium and chromium nitrides are promising. When depositing combinations of chemical elements on various substrates, studies are required aimed at investigating its microstructure and, mainly, residual stresses formed during the deposition of multilayer coatings. The purpose of this work is to investigate the structural-phase state and residual stresses of ZrN/CrN system coatings formed by plasma-assisted vacuum-arc method from the gas phase. Research methods. Samples with coatings of zirconium and chromium nitrides deposited on substrates of hard alloy VК8 are investigated. Transmission electron microscopy is used to study the microstructural characteristics of multilayered coatings and X-ray diffraction analysis is used to quantify macroscopic stresses. Results and discussion. Based on the experimental results obtained it is found that changing the modes of deposition of multilayer ZrN/CrN coatings with regard to rotation speeds of table and substrate holder leads to variations in microstructure, morphology and internal stresses of surface layers of multilayer coatings. It is shown that by changing conditions for the multilayer coating deposition the possibilities of forming ZrN/CrN coatings on the substrate made of VK8 alloy with nanoscale thickness of coating layers open up. X-ray diffraction analysis indicates mainly insignificant stresses, and at high table and substrate rotation speeds – high compressive stresses in the multilayer coating. Transmission electron microscopy revealed that CrN and ZrN coatings have a common multilayer coating growth texture at low rotation speeds, and at high speeds a textural misorientation of the phases of the coating layers is observed. Based on the results obtained it is possible to recommend coatings of ZrN/CrN system as hard coatings.

Effect of Solution Heat Treatment by Induction on UNS S31803 Duplex Stainless Steel Joints Welded with the Autogenous TIG Process

In the oil and gas industry, the manufacture of equipment using materials that resist aggressive media is one of the greatest challenges. UNS S31803 duplex stainless steel is widely used for this purpose owing to its good combination of mechanical and corrosion resistance. The objective of this work was to evaluate the effect of induction solution heat treatment using autogenous TIG welding on UNS S31803 DSS sheets. Sheet samples were subjected to two different treatment parameters for a duration of 10 s and at temperatures of 1050 and 1150 °C. The results obtained with the treatments were compared with those of the as-welded condition, which was the reference condition. Quantitative and qualitative analyses of the samples were carried out, in addition to microstructural characterization using confocal microscopy and a corrosion resistance study as per ASTM G48 standard. We observed that the best results were obtained with a treatment of 10 s at 1150 °C, which was able to eliminate chromium nitrides and re-establish the proper balance of the ferrite and austenite phases. In addition, the treatment was able to reduce hardness and provide welds free of cracks and discontinuities, also presenting a low corrosion rate.

Rapid coating preparation strategy for chromium nitride coated titanium bipolar plates of proton exchange membrane fuel cells

It is critical to develop a coating with sufficient comprehensive performances and efficient preparation strategy for the commercial application of metallic bipolar plate in proton exchange membrane full cell (PEMFC). In this work, chromium nitride coatings prepared by a rapid multi-arc ion plating (MIP) process with various nano thicknesses are investigated in the simulated PEMFC cathodic environments. Both the corrosion resistance and conductivity of the coatings increase with the growth of the coating thickness, which can be attributed to the increasing equivalent diameter, density, and area fraction of the droplets formed on the coating surfaces. The chromium nitride coating with a thickness of approximately 1.0 μm has the lowest I0.6 V (0.594 μA cm−2) and interfacial contact resistance (ICR, 6.54 mΩ cm2@1.4 MPa after corrosion test), achieving the 2025 technical targets proposed by the US Department of Energy for bipolar plates. This work shows that rapid preparation by MIP within 12 min is a potential strategy for chromium nitride coated titanium bipolar plates of PEMFCs at industrial scale.

Tuning Surface Plasmonic Resonance and Surface Wettability of Au/CrN Films Using Nitrogen-Containing Gas.

The surface plasmonic resonance, surface wettability, and related mechanical nanohardness and of face-centered-cubic (fcc) chromium nitride (CrN) films have been successfully manipulated via the simple method of tuning nitrogen-containing gas with different nitrogen-to-argon ratios, varying from 3.5 (N35), to 4.0 (N40), to 4.5 (N45), which is directly proportional to argon. All of the obtained CrN films showed that the surface wettability was due to hydrophilicity. All of the characteristics were mainly confirmed and explained by using X-ray diffraction (XRD) patterns, including plan-view and cross-section SEM images, with calculations of the average grain size performed via histograms accompanied by different preferred grain orientations. In the present work, not only the surface plasmonic resonance, but also the surface wettability and the related mechanical nanohardness of CrN films were found to be tunable via a simple method of introducing adjustable nitrogen-reactive-containing gas during the deposition process, while the authors suggest that the crystal orientation transition from the (111) to the (200) crystalline plane changed significantly with the nitrogen-containing gas. So the transition of the preferred orientation of CrN’s cubic close-packed from (111) to (200) varied at this composite, caused and found by the nitrogen-containing gas, which can be tuned by the nitrogen-to-argon ratio. The surface plasmonic resonance and photoluminescence quenching effects were coupled photon and electron oscillations, which could be observed, and which existed at the interface between the CrN and Au metals in the designed heterostructures.

Unlocking the influence of microstructural evolution on hardness and pitting corrosion in duplex stainless welded joints

In this study, the evolution of microstructure and its correlation with hardness and pitting corrosion resistance in duplex stainless steel (DSS) welded joints were investigated. The results showed that the precipitation of chromium nitride, refined grain size and large residual deformations contributed to the increase of microhardness in the heat affected zone (HAZ) and weld metal (WM). Poor pitting corrosion resistance was found in the HAZ, especially in the high temperature heat affected zone (HT-HAZ). The chromium nitride precipitates and secondary austenite were the main pitting nucleation sites.

Microstructure, fractal geometry and corrosion properties of CrN thin films: The effect of shot number and angular position

The effect of different plasma focus shots and angular positions (0° and 30°) on the properties of chromium nitride (CrN) coatings, deposited by a plasma focus (PF) device on stainless steel substrates, have been systematically investigated in this paper. The structural and morphological properties of CrN thin films were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). Moreover, the corrosion behavior of the CrN thin films was investigated using the ‘c’ method. The XRD patterns demonstrated the growth of the polycrystalline structure composed of CrN/Cr2N nanograins and the enhanced crystallinity of the CrN coatings upon increasing the shot numbers. In addition, AFM results showed enhanced multifractal properties of the sample prepared at 0° angular position and a reducing trend in these properties for the layers prepared at 30° angular position. Moreover, they exhibited sharp hillock-like features on the surface, corresponding to the columnar growth of the CrN coatings, which further protruded as the number of shots increased. The results of the corrosion test showed that the resistance of stainless-steel substrate was improved by depositing the CrN coatings due to the formation of a passive and protective layer on its surface. Notably, ceramic CrN film, prepared through 10 shots at 30° angular position, showed the best corrosion resistance. Our strategy is advantageous for designing and manufacturing novel devices and instruments based on CrN corrosion resistant coating.

Electron-impact ionization cross sections of small molecules containing Fe and Cr ∗ ∗ This work is dedicated to Enrico Clementi who pioneered the interdisciplinary use of quantum chemistry and computational modelling.

We present the electron-impact ionization cross sections (EICSs) of iron and chromium hydrides, nitrides, and oxides. The motivation of this work stems from the fact that chemical sputtering from a steel surface exposed to a hot plasma can create these molecules which in turn influence the composition and energy balance of the plasma. The latter influence is quantified by the EICS which we derive by using two semi-empirical methods which can be employed in the relevant energy range of 10–1000 eV. They are important molecular properties for plasma- and materials science. We discuss the foundations of the methods and present the cross sections of the high- and low-spin states of the species in their neutral ground states and of their cations.

Improving the mechanical, tribological, and electrochemical behavior of AISI 304 stainless steel by applying CrN single layer and Cr/CrN multilayer coatings

The purpose of this study was to assess the mechanical and tribological behavior of chromium nitride (CrN) single layer and multilayer nanostructured coatings of chromium/chromium nitride (Cr/CrN) applied on AISI 304 stainless steel to be used in a marine application. CrN and Cr/CrN coatings were performed using cathode arc evaporation a division of physical vapor deposition (CAE-PVD) method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and field emission scanning electron microscopy (FE-SEM) were utilized for phase identification of coatings and surface morphology, respectively. Nano-indentation method was used to investigate the mechanical behavior of coatings. The tribological behavior of the coatings was studied by the ball-on-disk method. The results indicate that the mechanical behavior of the Cr/CrN multilayer nanostructured coatings is better in comparison to the CrN single-layer coatings. The hardness values of CrN and Cr/CrN coatings were 21.5 and 23.3 GPa, respectively. The higher hardness of the nanolayered coating might be owing to blocking the movement of dislocations and microcracks by its layered structure. Furthermore, the tribological behavior of AISI 304 stainless steel was highly amended by applying the coatings. The coefficient of friction for CrN and Cr/CrN coatings in a dry condition decreased from 0.61 to 0.49 and 0.46, respectively. Also, the CoF value reduced from 0.57 to 0.38 and 0.37 in 3.5 wt% NaCl electrolyte. The lower friction coefficient of the Cr/CrN multilayer nanostructured coating is perhaps due to its higher hardness and lower roughness.

Chromium Nitride Umpolung Tuned by the Locus of Oxidation.

Oxidation of a series of CrV nitride salen complexes (CrVNSalR) with different para-phenolate substituents (R = CF3, tBu, NMe2) was investigated to determine how the locus of oxidation (either metal or ligand) dictates reactivity at the nitride. Para-phenolate substituents were chosen to provide maximum variation in the electron-donating ability of the tetradentate ligand at a site remote from the metal coordination sphere. We show that one-electron oxidation affords CrVI nitrides ([CrVINSalR]+; R = CF3, tBu) and a localized CrV nitride phenoxyl radical for the more electron-donating NMe2 substituent ([CrVNSalNMe2]•+). The facile nitride homocoupling observed for the MnVI analogues was significantly attenuated for the CrVI complexes due to a smaller increase in nitride character in the M≡N π* orbitals for Cr relative to Mn. Upon oxidation, both the calculated nitride natural population analysis (NPA) charge and energy of molecular orbitals associated with the {Cr≡N} unit change to a lesser extent for the CrV ligand radical derivative ([CrVNSalNMe2]•+) in comparison to the CrVI derivatives ([CrVINSalR]+; R = CF3, tBu). As a result, [CrVNSalNMe2]•+ reacts with B(C6F5)3, thus exhibiting similar nucleophilic reactivity to the neutral CrV nitride derivatives. In contrast, the CrVI derivatives ([CrVINSalR]+; R = CF3, tBu) act as electrophiles, displaying facile reactivity with PPh3 and no reaction with B(C6F5)3. Thus, while oxidation to the ligand radical does not change the reactivity profile, metal-based oxidation to CrVI results in umpolung, a switch from nucleophilic to electrophilic reactivity at the terminal nitride.

Effect of gas nitriding on 316 L stainless steel lattice manufactured via selective laser melting

Nitriding is well-known as a surface treatment method to improve the wear and fatigue properties. This work demonstrates the capability of nitriding in improving the overall mechanical performance of the open cellular structure, by taking the 316 L stainless steel lattice structure fabricated by additive manufacturing as an example. The microstructure, composition distribution, and compressive properties of the obtained structure were analyzed. It is found that the effective elastic modulus, compressive proof strength, and energy absorption capacity of the lattice were improved after conventional gas nitriding. A nitrided layer with a thickness of about 60 μm was formed on the surface of the nitrided parts, including an outer layer of chromium nitrides and an inner layer containing expanded austenite. The nitrided lattices with thinner struts were strengthened more due to the higher proportion of the nitrided layer. Meanwhile, the lattices were embrittled after nitriding. However, the toughness of the lattice can be compensated by adjusting the lattice structure, such as changing the angle between the strut and the compression direction so that a lattice with good strength and toughness can be obtained.

Analysis of the Generation State of Fine Precipitates in Steel

Fine precipitates in steel have various effects on the properties of steel products. Therefore, it is important to investigate the state of existence of precipitates in steel in order to consider their effect on the material. In this study, the size and shape of Nb and V precipitates were observed by electron microscopy and the amount of precipitates was evaluated by electrolytic extraction analysis in martensitic stainless steels which has excellent heat resistance. For steels with a certain chemical composition, stable chromium nitride (Cr2N) formation was observed when only Nb was added, whereas combined addition of Nb and V suppressed the formation of Cr2N and produced extremely fine precipitates in the steel (in lath martensite). The fine precipitates could be observed in thin film samples by using a high-resolution transmission electron microscope (TEM). In order to evaluate the state of formation of the fine precipitates in the steel quantitatively, the difference in the precipitation behaviors between the two materials was investigated by the size-classified quantitative analysis method. This method is considered to be a useful analytical technique in the development and design of high performance steels using fine nitrides and carbides with sizes of the several nm order.

Study on the infrared emissivity of nonstoichiometric titanium chromium nitride films

Nonstoichiometric titanium chromium nitride (TiCrN) thin films with different nitrogen stoichiometric ratio were prepared by reactive magnetron co-sputtering. The nitrogen stoichiometric ratio was adjusted by change in the sputtering power. The phase compositions, morphology, adhesion force, resistivity and infrared emissivity were studied systematically. The results show that the adhesion force increased with increasing of the nitrogen stoichiometric ratio. The crystallinity was poor and the grain size was small when the nitrogen stoichiometric ratio was 0.35, leading to a great increase of resistivity and infrared emissivity of TiCrN film. When the nitrogen stoichiometric ratio was 0.44, the films crystallized and severe deformation of TiCrN crystal structure led to high resistivity and infrared emissivity. After the nitrogen stoichiometric ratio reached 0.58, serious deformation of TiCrN crystal weakened, and the combined effect of crystal deformation and carrier density caused the variation of the infrared emissivity. The infrared emissivity value of TiCrN film with nitrogen stoichiometric ratio of 0.58 was almost close to the value with nitrogen stoichiometric ratio of 0.81. Reduction of nitrogen stoichiometric ratio appropriately or decrease of crystal deformation in nonstoichiometric crystal TiCrN films was beneficial to reduce the infrared emissivity. The infrared emissivity of TiCrN films could be reduced to about 0.3.

Current status and future potential of wear-resistant coatings and articulating surfaces for hip and knee implants.

Hip and knee joint replacements are common and largely successful procedures that utilise implants to restore mobility and relieve pain for patients suffering from e.g. osteoarthritis. However, metallic ions and particles released from both the bearing surfaces and non-articulating interfaces, as in modular components, can cause hypersensitivity and local tissue necrosis, while particles originating from a polymer component have been associated with aseptic loosening and osteolysis. Implant coatings have the potential to improve properties compared to both bulk metal and ceramic alternatives. Ceramic coatings have the potential to increase scratch resistance, enhance wettability and reduce wear of the articulating surfaces compared to the metallic substrate, whilst maintaining overall toughness of the implant ensuring a lower risk of catastrophic failure of the device compared to use of a bulk ceramic. Coatings can also act as barriers to inhibit ion release from the underlying material caused by corrosion. This review aims to provide a comprehensive overview of wear-resistant coatings for joint replacements – both those that are in current clinical use as well as those under investigation for future use. While the majority of coatings belong predominantly in the latter group, a few coated implants have been successfully marketed and are available for clinical use in specific applications. Commercially available coatings for implants include titanium nitride (TiN), titanium niobium nitride (TiNbN), oxidized zirconium (OxZr) and zirconium nitride (ZrN) based coatings, whereas current research is focused not only on these, but also on diamond-like-carbon (DLC), silicon nitride (SiN), chromium nitride (CrN) and tantalum-based coatings (TaN and TaO). The coating materials referred to above that are still at the research stage have been shown to be non-cytotoxic and to reduce wear in a laboratory setting. However, the adhesion of implant coatings remains a main area of concern, as poor adhesion can cause delamination and excessive wear. In clinical applications zirconium implant surfaces treated to achieve a zirconium oxide film and TiNbN coated implants have however been proven comparable to traditional cobalt chromium implants with regards to revision numbers. In addition, the chromium ion levels measured in the plasma of patients were lower and allergy symptoms were relieved. Therefore, coated implants could be considered an alternative to uncoated metal implants, in particular for patients with metal hypersensitivity. There have also been unsuccessful introductions to the market, such as DLC coated implants, and therefore this review also attempts to summarize the lessons learnt.

Time domain and frequency domain of coated milling inserts using FFT spectrum

ABSTRACT Quality is determined by machines, materials, equipment, and lead times. The quality of aircraft materials such as aluminum and its alloys could greatly improve their applications. The difficulty of efficiently and reasonably machining certain materials limits their applicability. The purpose of this paper is to increase the quality of the vibration responses. Specifically, we examine the effects of the machining parameters on vibration (Time and Frequency domains). The end milling process is used to machine the AA6082T6 workpiece material. Speed (S), feed (F), depth of cut (DoC), and coated cutting inserts are the machining parameters. Tungsten carbide inserts (UNC), tungsten carbide inserts coated with Aluminum Chromium Nitride (AP3), and tungsten carbide inserts coated with Diamond-Like Carbon (DLC) were employed in this study. The minimum amplitude of 0.1173 g (m/s2) is seen at 710 rpm, 40 mm/min, and 0.5 mm of the DLC coated tool at a frequency of 930 Hz, according to the data. By comparing it to other cutting inserts, the DLC coated tool is given the smallest amplitude and minimum time domain. According to the findings, if the DLC coated insert is used in the machining process, the material’s surface finish will be much enhanced, and the material had good mechanical qualities.

Investigation of friction and wear resistance of carbonitrided AISI 4130 steels using single and multi-pass scratch technique

The present paper investigates the friction and wear resistance of carbonitrided AISI 4130 steels using single and multi-pass scratch techniques. The influence of carbon concentration in high-temperature gas carbonitriding on friction, wear, and corrosion behavior was studied. The microstructure and morphological properties of carbonitrided layers were investigated employing optical microscope and XRD. The corrosion performance of carbonitrided layers was also evaluated using potentiodynamic polarization in 3.5 wt.% aqueous solution of NaCl. The results of microstructure showed the formation of an arrangement of carbonitrides, chromium nitride, retained austenite, and [Formula: see text] carbides phases in the carbonitrided layers. The carbonitrided layer microhardness increased as a function of increasing carbon concentration to attain a maximum value of about 980 HV0.1 at a carbon content between 1 and 1.2%. The microhardness value was more than 3 times than those of the untreated AISI 4130 steels. Moreover, carbon content has a significant influence on the scratch resistance. For single pass, a critical load (LC1) of about 3.5 N was found. The use of multi-pass scratching allowed to examine friction coefficient, wear volume, and damage mechanism. Carbonitrided layers revealed a low friction coefficient (0.06) and a low wear volume that does not exceed [Formula: see text]. Moreover, the multi-pass scratch technique can extract valuable information about the wear behavior of the carbonitrided layers. The results of corrosion test showed that the formation of [Formula: see text], [Formula: see text] and chromium nitride phases in carbonitrided layers were at the origin of high electrochemical resistance.

Surface roughness control in nanolaminate coatings of chromium and tungsten nitrides

Frictional forces arising during machining operations of cutting tools generate high temperatures at the tool-workpiece interface, promoting tool-wear phenomena. Surface roughness is acknowledged to contribute significantly to friction generation, and its control is therefore of paramount importance. Structural confinement of growth defects in multilayer coating architectures with individual layers thickness in the nanometric regime can help reduce surface roughness development. Here, a set of nanolaminate coatings consisting in an alternated repetition of cubic chromium nitride (CrN) and cubic tungsten nitride (c-WN) layers is fabricated via unbalanced DC magnetron Sputtering. The individual layers thickness range is between 100 and 10 nm. The reduction of surface roughness as a function of individual layers thickness is demonstrated by semi-contact Atomic Force Microscopy (AFM). Scherrer analysis performed on X-Ray Diffraction (XRD) crystallographic signals shows that the reduction in surface roughness is correlated to a reduction in crystallite size, modulated by the nanolaminate architecture. Conformity and uniformity of multilayer coatings is observed via FIB-SEM cross-section micrographs. The relative contribution of CrN and c-WN layers to the overall roughness development is investigated through a SEM cross-section micrograph-based analysis. The microstructural and topographical features of nanostructured CrN/c-WN multilayer coatings are correlated to the observations from the cross-section analysis and discussed in terms of the energy transfer to the growing surface during each deposition step. • Nanolaminate CrN/WN coatings are deposited via DC-magnetron sputtering. • Surface roughness decreases with the individual layers thickness. • The nanolaminate structure hinders the development of structural defects and asperities. • Roughness build-up is analyzed through a novel layer-by layer approach. • The contribution of the two materials is discussed in terms of sputtering yield differences.

Lithium dendrite suppression with Li3N-rich protection layer formation on 3D anode via ultra-low temperature nitriding

We demonstrate an effective strategy to prohibit lithium dendrite formation in lithium metal batteries (LMBs) by forming a Li3N-rich protection solid electrolyte interphase (SEI) layer on a three-dimensional (3D) austenitic stainless steel (SS) surface, which maintains the structural stability during Li plating/stripping. The porous SS with 20% Cr is treated by ultra-low temperature ion-nitriding (250 ∼ 350 °C) for energy-saving, resulting in a lithiophilic nitride layer with a chromium nitride (CrN) phase on the surface, evidenced by the X-ray photoelectron spectroscopy (XPS) and further confirmed by Density functional theory (DFT) calculation. Upon cycling, it spontaneously reacts with metallic Li to form a strong and highly ionic conductive Li3N protection layer, which functionally inhibit continuous side reactions with electrolyte and facilitate the Li-ions transport, consequently leading to a flat Li deposition and ultralong cycling. Additionally, the 3D skeleton of SS reduces the areal current density and provides enough space to relieve volume expansion. The electrochemical results showed that the N-350-SS/Li (porous SS nitrided at 350℃ and composited with Li metal) anode in symmetrical cells exhibited extremely low voltage hysteresis of 14 mV and prolonged excellent cycling for over 2500 h in the normal LiPF6 electrolyte at 1 mA cm−2. The half cells retained an excellent Coulombic efficiency (CE) of above 98% and the full cells retained 98.0% of its initial capacity without much degradation after 200 cycles at 3C. This enhancement method is simple and low-cost and the SS can be successfully applied in the real high-energy–density LMBs.