Interdiffusion Layer Research Articles

A study on pre-treatment with rotation accelerated shot peening in multi-NbN films by double glow plasma surface metallurgy

Multi-NbN films manufactured by a hybrid process comprising pre-treatment rotation accelerated shot peening (RASP) and double glow plasma surface metallurgy (DG technique) and designed to protect titanium alloys were assessed to determine their tribological and mechanical properties. The surface microstructures of a modified TA15 alloy were characterized using X-ray diffraction, scanning electron microscopy, 3D-profilometer and micro-Vickers hardness testing. The results reveal that the distribution of N concentration on layers was influenced by the pre-treatment with RASP, in which a dense nitride gradient layer was formed inside the films and a new phase β-Nb2N occurred at the film surface. This is because a large number of defects on the surface layer were generated by the pre-treatment with RASP. While multi-NbN films on the original sample without new phase detected can be divided into three zones—NbTi interdiffusion layer, Nb-Ti-N interdiffusion layer, and NbN layer. Strong increase in surface hardness was verified in correspondence of elevated peening velocity, and the hardest RASP-60 m/s sample is up to 30.1803 GPa. However, the thickness of films cannot keep increasing trend in agreement with increasing shot peeing velocity. The thickest films occurred on the RASP-40 m/s sample, is 5.85 μm. The results show that the RASP-treated samples exhibited more serious damage than the untreated sample, due to the formation of β-Nb2N phase with brittle structure which bonding on the course surface are incapable of overcoming the damage of shearing stress from counterparts. And once starting to crack, the films that are supposed to protect the substrate are turned into hard abrasive particles that adversely affect the wear resistance of the substrate.

Temperature Effects on Interdiffusion of Al and U-Mo under Irradiation

A high-energy Xe ion irradiation experiment was conducted to investigate the temperature dependence of interdiffusion in bilayer Al-UMo samples under irradiation. The amount of interdiffusion achieved at a fixed dose with the increase of temperature showed a clear transition at 175°C (with an estimated error in the range of ±10°C) from temperature-independent to temperature-dependent behavior. The activation energy derived from the curve of interdiffusion quantity vs. irradiation temperature is 0.77±0.16 eV. This information has been utilized to understand the temperature effect on the interdiffusion process that occurred at the interfaces of U-Mo particles and the Al matrix in U-Mo/Al dispersion fuels, whose magnitude significantly impacts the fuel's performance. Although this temperature effect was deemed important, it cannot be examined directly using in-pile irradiation data, as fuel temperatures cannot be measured in reactor irradiation and are highly correlated with fission rate and thermal conductivity evolution. To connect the knowledge accumulated from ion irradiation with in-pile irradiation data, simulation of a full-sized U-Mo/Al dispersion fuel plate irradiated in the FUTURE test in the BR2 reactor was performed with the Dispersion Analysis Research Tool (DART), a dispersion fuel performance code. DART is equipped with an interaction or interdiffusion layer (IL) growth correlation formulated to describe the temperature dependence of ion mixing results. The agreement between calculated and measured fuel meat constituent volume fractions and swelling data demonstrated that the temperature effect on in-pile Al-UMo interdiffusion is well captured with the correlation. In this case, the fitted activation energy is 0.70 eV. Considering the uncertainties associated with the ion irradiation data, the activation energy obtained from in-pile data fitting is in accord with that from ion irradiation results.

Interfacial reaction and mechanical properties of diffusion bonded titanium/17-4 PH stainless steel dissimilar joint using a silver interlayer

Diffusion bonding of titanium (Ti) to 17-4 PH high strength stainless steel is challenging owing to the formation of brittle Ti-Fe intermetallic compounds (IMCs) at joint interface. In the current study, it was demonstrated that such detrimental Ti-Fe IMCs can be effectively eradicated by using a silver (Ag) interlayer. The diffusion bonded Ti/Ag/17-4 PH stainless steel is characterized by Ti-Ag solid solution, TiAg, remnant Ag interlayer and Ag-(Fe, Cr, Ni) interdiffusion layer. The interfacial reaction phase TiAg exhibited no detrimental effect on bonding strength. During tensile test, ductile fracture took place in the remaining Ag interlayer of resultant joint. Bonding strength up to ∼420 MPa was obtained over bonding durations in the range of 15 ∼ 25 min. It is thus concluded that using an Ag interlayer is highly appealing in improving bonding strength of diffusion bonded Ti/17-4 PH stainless steel dissimilar joint.

Microstructure and properties of FeCoNi1.5CrCu/2024Al composites prepared by microwave sintering

In this investigation, FeCoNi1.5CrCu high-entropy alloy (HEA) was prepared by mechanical alloying, following which HEA particles reinforced 2024 aluminum matrix composites were obtained using a microwave with low-temperature sintering. The microstructural characterization and mechanical properties of the composites under different sintering time at isothermal temperature were investigated systematically. The results showed that HEA particles at first diffuse uniformly and then agglomerate with an increase in the sintering time. An interdiffusion (ID) layer exists between the HEA particle and the matrix, and high-density dislocations surround the interface of the HEA/2024Al composite, with a width of 80–120 nm. The hardness and elastic modulus of the interface was tested using nanoindentation technique, which presents excellent interface micro-domains with the mechanical strength reaching about 1331.1 MPa and 47.544 GPa. At 40 min of sintering time, the compressive strength, yield strength and microhardness of the composites were reaching the maximum of 248.7 MPa, 227.4 MPa and 93.1 HV, respectively.

Strength and Deformation Properties of Low-Alloy Steel Bolts with Electroless Ni-P Coating: An Investigation of Two Thermal Routes

Low-alloy steel bolts are used in applications where high strength is needed, although they presented low corrosion resistance, limiting their application in harsh environments. Ni-P coatings could be an alternative to protect low-alloy steel bolts against corrosion. However, Ni-P coatings must be submitted to an interdiffusion post-heat treatment, which provokes severe microstructural changes in the steel substrate, lowering its strength. This research aims to investigate two new thermal routes to obtain Ni-P coatings on low-alloy steel bolts, aiming to preserve the steel substrate's resistance and deformation properties, addressing the ASTM A320/L7 requirements. The first route proposed consists of obtaining the Ni-P coating on an austempered steel substrate, instead of a quenched/tempered one. This approach resulted in less microstructural changes during the post-heat treatment, although poor impact properties were achieved. The second thermal route consists of Ni-P coating on a quenched substrate, followed by a single-step post-heat treatment aiming to temper the substrate and promote the coatings' interdiffusion at the same time. The single-step post-heat treatment performed at 600 °C for 4 h resulted in appropriated mechanical properties while assuring the creation of a proper coating/steel interdiffusion layer, showing the feasibility to use Ni-P coatings in low-alloy steel to be used in harsh environments.

Tantalum coating inhibits Ni-migration from titanium out-diffusion in NiTi shape memory biomedical alloy

Despite the presence of over 56% Ni by weight, equiatomic NiTi is generally considered biocompatible as it naturally oxidises to form a surface oxide mainly composed of biocompatible oxides of titanium (TiOx). This layer is formed by an oxidation mechanism that promotes out-diffusion of Ti leaving a Ti-depleted, Ni rich subsurface. The long-term in vivo stability of the naturally grown TiOx layer has been a concern as Ni can leach out through this thin, defective layer. The leaching of nickel (Ni) is thus a continuing threat to the alloy’s otherwise outstanding biocompatibility. We have found that a layer of reactively sputtered tantalum (Ta) oxide on the bulk NiTi restricts Ti-out-migration through a biocompatible Ti/Ta inter-diffusion layer that provides a larger barrier against Ni leaching. We have investigated this inter-diffusion as a function of sputtering process parameters and post processing treatments. Surface and interface analytical techniques such as X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, cross sectional transmission electron microscopy and non-destructive ion beam analysis techniques such as Rutherford backscattering spectrometry and particle induced X-ray emission were used to evaluate the nature of this inter-diffusion layer which can improve long-term biocompatibility of NiTi.

Oxidation of Nickel-Coated AISI 430 Alloy: Effect of Pre-oxidation and Fe0.5Ni0.5 Inter-diffusion Layer

The oxidation behavior of nickel (Ni)-coated AISI 430 alloy was investigated at 800 °C in moisture-saturated (~ 3% H2O) air. Effects of pre-oxidation of AISI 430 in air and inter-diffusion layer (Fe0.5Ni0.5) of Ni-coated AISI 430, in dilute hydrogen (Ar–3%H2) at 800 °C, on the oxidation behavior were also studied. Microstructure, elemental chemistry, and compound/oxide formation across the reaction zones/oxide layer were analyzed by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction techniques. Multilayered oxides/reaction zones were found for all the samples. Ni-coated AISI 430 exhibits the lowest chromium diffusion into the oxide scale from the AISI 430/oxide scale interface. Pre-oxidation of AISI 430 and inter-diffusion of Ni-coated AISI 430 show excessive chromium diffusion into the reaction zone/oxide scale and interfacial porosity.

Microstructure, mechanical and tribological properties of cold sprayed Ti6Al4V–CoCr composite coatings

Metal-matrix composite (MMC) coatings are advanced materials, composed of two or more phases that can be tailored based on the industrial needs such as lightweight and wear-resistance. Cold spray (CS) technology is highly suitable to develop these MMC coatings as it is a low temperature deposition method, which does not involve particle melting, hence retaining the original properties of the materials. Ti–6Al–4V (Ti64) is a common alloy used in aerospace applications owing to its lightweight and high yield strength. Recently, cold sprayed Ti64 coatings have shown promise to repair damaged or enhance surfaces of Ti components. However, there are still several issues with cold sprayed Ti64 coatings, such as relatively high porosity level and low wear-resistance. To solve these, a novel approach is to incorporate CoCr (ASTM F75) as reinforcing metal alloy particles into the Ti64 matrix to form a Ti64–CoCr composite coating. Pure Ti64 and pure CoCr coatings were also deposited as a comparison. The Ti64–CoCr composite coating achieved low porosity level (0.9%), high hardness (434 HV) and high wear resistance (1.7 × 10−4 mm3/Nm) compared to the Ti64 coatings. These properties were obtained while maintaining the original phases of the feedstock Ti64 and CoCr powders and achieving adhesion strength above 60 MPa. A 20 nm thick Ti–Co interdiffusion layer was also observed at the interface of CoCr and Ti64 particles under TEM. These results showed that Ti64–CoCr composite coating is a promising lightweight and wear resistant metallic coating for aerospace application.

Microstructure evolution and phase transformation of heavy-ion irradiated U–Mo/Al fuels

The microstructure evolution and phase transformation of the interdiffusion layer resulting from the interaction between U–Mo and Al in U–Mo/Al bilayer systems irradiated from 140 °C to 275 °C are discussed. Heavy ion irradiation was used as a convenient tool to produce an interdiffusion layer comparable to those occurring during in-pile irradiation. A burn-up equivalent of up to ∼7.7×1020f/cm3 has been reached to simulate the early in-pile irradiation. Scanning and transmission electron microscopy coupled with energy dispersive spectroscopy were performed to determine the phase and the composition of the induced interdiffusion layer.The present analysis reveals that the U–Mo/Al interdiffusion layer is completely amorphous up to an irradiation temperature of 200 °C. In our experimental geometry, nanograins start to form from 220 °C, propagating from the Al layer towards the U–Mo layer. The γ-U-Mo and the Al layers retain their crystallinity. Furthermore, with increasing irradiation temperature, the Al proportion in the interdiffusion layer rises, indicating an enhanced Al atomic flow with increasing irradiation temperature.

Ni coating on 316L stainless steel using cage plasma treatment: Feasibility and swelling studies

A modified cage plasma nitriding technique is used to coat a Ni film onto a 316L substrate as a protective layer for austenitic steels in molten fluoride salts. The coating is achieved by deposition of Ni atoms sputtered from a Ni cage with a 316L substrate floated at the same potential as the cage to reduce plasma sputtering on the substrate. The Ni coating is porosity-free and precipitation-free and forms a γ-(Fe, Ni) phase due to interdiffusion from the substrate. Beneath the interdiffusion layer exists a thick γ-phase layer mainly affected by long-range nitrogen diffusion along the grain boundary. This layer develops grain boundary Cr nitride precipitates. Ion irradiation on the polished cross-section of the plasma-treated sample shows no void swelling in the surface-deposited Ni layer, very limited void formation in N diffusion layer, and significant void swelling in bulk unaffected by nitrogen. The studies demonstrate the feasibility of the technique for Ni coating and show good swelling resistance of the coating layer and N diffusion-affected layer. Mechanisms are discussed.

Microstructural characteristics and mechanical properties of the Al–Si coating on press hardened 22MnB5 steel

The microstructural characteristics and mechanical properties of the phases in the substrate-coating interdiffusion layer of an Al–10%Si coated 22MnB5 press hardened steel (PHS) were studied by means of electron diffraction, chemical analysis, and nano-indentation. The interdiffusion layer of the Al–Si coated PHS, austenitized at 900 °C for 6.5 min, consisted of α-Fe(Al), Fe3Al, FeAl, Fe2Al5, and an Fe–Al–Si ternary intermetallic phase. The chemical analysis results indicated that the Fe3Al and Fe2Al5 phases were non-stoichiometric, and their composition ranges were not fully consistent with existing Fe–Al and Fe–Al–Si phase diagrams. These results partly explain the significant discrepancies between research groups in phase analysis of the interdiffusion layer. The observed Fe–Al or Fe–Al–Si phases were harder and more brittle compared to the martensitic matrix. With increasing austenitizing temperature and hold time, the thickness of the interdiffusion layer increased and the major constituent in the coating changed from Fe2Al5 to a multi-layered structure of FeAl, Fe3Al, and Fe(Al), leading to significant softening of the interdiffusion layer. Free bend testing was employed to investigate cracking and fracture behavior of the interdiffusion layer. The cracks formed in the thicker coating associated with the highest austenitizing temperature propagated deeper into the substrate material than in the case of lower austenitizing temperatures. Fracture of the interdiffusion layer involved transgranular cleavage and intergranular fracture features. The fracture surface appearance depended on both the phases present and the Al distribution in the coating. FeAl phase, known to be relatively “ductile”, was more susceptible to intergranular fracture than other phases (Fe2Al5, Fe3Al, and α-Fe(Al)).

Microstructure, nano-mechanical characterization, and fretting wear behavior of plasma surface Cr-Nb alloying on γ-TiAl

In this study, surface Cr-Nb alloying was realized on γ-TiAl using double glow plasma hollow cathode discharge technique. An inter-diffusion layer was generated under the surface, composed of Cr2Nb intermetallic compounds. After Cr-Nb alloying, the surface nanohardness of γ-TiAl increased from 5.65 to 11.61 GPa. The surface H/E and H3/E2 increased from 3.37 to 5.98 and from 0.64 to 4.15, respectively. Cr-Nb alloying and its effect on fretting wear were investigated. The surface treatment resulted in improved plastic deformation and fretting wear resistance of γ-TiAl. The fretting wear test showed that an average friction coefficient of γ-TiAl against Si3N4 ball was significantly decreased after Cr-Nb alloying. The fluctuation of friction coefficient during running-in stage was significantly improved. The friction behavior of both γ-TiAl before and after Cr-Nb alloying could be divided into distinctive stages including formation of debris, flaking, formation of crack, and delamination. It was observed that the high hardness, resistance to plastic deformation, and fatigue resistance of γ-TiAl after Cr-Nb alloying could inhibit the formation of debris and delamination during friction test. The fretting wear scar area and the maximum wear scar depth were decreased, indicating that the wear resistance of γ-TiAl has been greatly improved after Cr-Nb alloying. The results indicated that plasma surface Cr-Nb alloying is an effective way for improving the fretting wear resistance of γ-TiAl in aviation area.

High Electrical and Thermal Conductivity of Nano-Ag Paste for Power Electronic Applications

The nano-Ag paste consisted of Ag nanoparticles and organic solvents. These organics would be removed by evaporation or decomposition during sintering. When the sintering temperature was 300 °C, the resistivity of sintered bulk was 8.35 × 10−6 Ω cm, and its thermal conductivity was 247 W m−1 K−1. The Si/SiC chips and direct bonding copper (DBC) substrates could be bonded by this nano-Ag paste at low temperature. The bonding interface, sintered microstructure and shear strength of Si/SiC chip attachment were investigated by scanning electron microscopy, transmission electron microscopy and shear tests. Results showed that the sintered Ag layer was porous structure and tightly adhered to the electroless nickel immersion gold surface of DBC substrate and formed the continuous Ag–Au interdiffusion layer. The shear strength of Si and SiC chip attachments was higher than 35 MPa when the sintering pressure was 10 MPa. The fracture occurred inside the sintered Ag layer, and the fracture surface had obvious plastic deformation.

Predicting and controlling interfacial microstructure of magnesium/aluminum bimetallic structures for improved interfacial bonding

Abstract In this study, an overcasting process followed by a low-temperature (200°C) annealing schedule has been developed to bond magnesium to aluminum alloys. ProCAST software was used to optimize the process parameters during the overcasting process which lead to Mg/Al bimetallic structures to be successfully produced without formation of Mg-Al intermetallic phases. Detailed microstructure evolution during annealing, including the formation and growth of Al-Mg interdiffusion layer and intermetallic phases (Al12Mg17 and Al3Mg2), was experimentally observed for the first time with direct evidence, and predicted using Calculation of Phase Diagrams (CALPHAD) modeling. Maximum interfacial strength was achieved when the interdiffusion layer formed at the Mg/Al interface reached a maximum thickness the without formation of brittle intermetallic compounds. The precise diffusion modeling of the Mg/Al interface provides an efficient way to optimize and control the interfacial microstructure of Mg/Al bimetallic structures for improved interfacial bonding.

Electrochemical Flash Sintering: A New Tool to Obtain All Solid-State Batteries in Few Seconds

Nowadays, inorganic All Solid-State Batteries (ASSBs) encounter a strong resurgence of scientific and technological interest stimulated by the discovery of new high conductivity solid electrolytes at room temperature (≥ 1 mS), as well as the development of fast Electrical Current Activated Sintering (ECAS) processes. One of the advantages of ASSBs is that they guarantee a unique safety due to the chemical and thermal stability of the materials. However, manufacturing dense ceramics requires sintering temperatures generally higher than 700 °C to lead to optimal mechanical and conductive properties. At these temperatures, the occurrence of undesired chemical reactions at the interfaces is an issue for electrochemical applications due to the formation of interdiffusion layers that block the charge transfer.For this purpose, Flash Sintering (FS) is very effective to densify conductive ceramics in a few seconds at significantly lower temperatures compared to conventional sintering.1,2 FS consists in making the current directly flows through the sample without neither the use of a conductive die nor the application of a charge. However, this technique requires a reversible electrochemical reaction to allow the charge transfer between the electronic conductor (i.e. the current collectors) and the ionic conductor (i.e. ceramic electrolyte).3 In the case of pure cationic conductors (Li+, Na+, K+, etc.), Pt electrodes which are commonly used for FS, are herein blocking electrodes preventing the current from flowing. A mixed cationic electronic conductor is then required to ensure the charge transfer reaction.Through this work, we demonstrate the feasibility of FS on Li+ ionic conductors such as Li1.3Al0.3Ti1.7(PO4)3 (LATP) or Li1.5Al0.3Ge1.5(PO4)3 (LAGP), using LiCoO2 (LCO) or LiNi1/3Mn1/3Co1/3O2 (NMC) mixed Li+/e- conductors as electrode materials. Using the concept of Electrochemical Flash Sintering, the “flash” event was obtained on two multi-component systems: LATP sandwiched between two pure LCO layers as electrodes and LATP sandwiched between two composite electrodes (LCO + LATP). Microstructural and chemical analyses were employed to characterise the densification at the vicinity of the interfaces. It is shown that a composite electrode both allows the flash to occur and prevents the delamination observed with pure LCO by lowering interfacial strains.4 This multi-material architecture turns out to be the one of an All-Solid-State Li-ion Battery, opening the path of using FS as a promising fast process to build functional multi-materials for energy storage devices. 1. Cologna, M.; Rashkova, B.; Raj, R. Flash sintering of nanograin zirconia in < 5 s at 850°C. J. Am. Ceram. Soc. 2010, 93, 3556–3559.2. Steil, M. C.; Marinha, D.; Aman, Y.; Gomes, J. R. C.; Kleitz, M. From conventional ac flash-sintering of YSZ to hyper-flash and double flash. J. Eur. Ceram. Soc. 2013, 33, 2093–3. Caliman, L.B.; Bouchet, R.; Gouvea, D.; Soudant, P.; Steil, M.C. Flash sintering of ionic conductors: the need of a reversible electrochemical reaction, J. Eur. Ceram. Soc. 2016, 36, 1253–1260.4. Lachal, M.; El. Khal, H.; Bouvard, D.; Chaix, J-M.; Bouchet, R.; Steil, M.C. Electrochemical Flash Sintering of advanced multi-materials for energy storage devices, J. Eur. Ceram. Soc. submitted. Figure 1

Microstructural characterization of accident tolerant fuel cladding with Cr–Al alloy coating layer after oxidation at 1200 °C in a steam environment

Zr alloy specimens were coated with Cr–Al alloy to enhance their resistance to oxidation. The coated samples were oxidized at 1200 °C in a steam environment for 300 s and showed extremely low oxidation when compared to uncoated Zr alloy specimens. The microstructure and elemental distribution of the oxides formed on the surface of Cr–Al alloys have been investigated by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). A very thin protective layer of Cr2O3 formed on the outer surface of the Cr–Al alloy, and a thin Al2O3 layer was also observed in the Cr–Al alloy matrix, near the surface. Our results suggest that these two oxide layers near the surface confers excellent oxidation resistance to the Cr–Al alloy. Even after exposure to a high temperature of 1200 °C, inter-diffusion between the Cr–Al alloy and the Zr alloy occurred in very few regions near the interface. Analysis of the inter-diffusion layer by high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS) measurement confirmed its identity as Cr2Zr.

TiO2 and Co multilayer thin films via DC magnetron sputtering at room temperature: Interface properties

In this work, we prepared TiO2 and Co multilayer thin films via DC magnetron sputtering method on (100) GaAs and (100) Si substrates. The power for each target (TiO2 and Co), deposition time of the layers, and pressure during deposition were kept constant. From XRD, Raman, and IR measurements, the formation of the rutile and triclinic Co phases were identified in the multilayer thin films. An annealing process was carried in situ on all samples and subsequent to the deposition stage during 2 h. The substrate used was GaAs and Si wafer, favoring the formation and growth of the found phases. The diffusion and interdiffusion of the layers in the thin films were determined from Rutherford Backscattering Spectroscopy (RBS). In particular, Co and Ga were observed to associate after the annealing process according to the depth profiles. Due to the interdiffusion layers, the parallel magnetic contribution is not significant in the bilayer. Curves I-V of the Co/TiO2 bilayer showed the presence of resistive switching, according to the bipolar resistive. A correlation between synthesis parameters and the physical properties of the multilayers is presented.

Oxidation performance and degradation mechanism of the slurry aluminide coating deposited on Super304H in steam at 600–650 °C

A triple-layered slurry aluminide coating was prepared on Super304H, composed of Al-rich FeAl layer, Fe-rich FeAl layer and α-Fe(Cr, Al, Ni) interdiffusion layer dispersed with (Ni, Fe)Al particles from outer to inner. Oxidation and degradation process of the coating has been investigated at 600 °C~650 °C in steam, by scanning electron microscopy (SEM) and transmission electron microscope (TEM). Results showed an extremely thin α-Al2O3 scale was formed on the coating. The microstructural degradation of the aluminide coating occurred due to phase transformation from FeAl to α-Fe and (Ni, Fe)Al particles near the interface between the FeAl layer and the interdiffusion zone. Related mechanisms were discussed.

A combined experimental and first-principle study on the effect of plasma surface Ta–W co-alloying on the oxidation behavior of γ-TiAl at 900 °C

Abstract

Effect of interfacial interdiffusion on magnetism in epitaxial Fe4N films on LaAlO3 substrates

Epitaxial Fe4N thin films grown on lattice-matched LaAlO3 (LAO) substrate using sputtering and molecular beam epitaxy techniques have been studied in this work. Within the sputtering process, films were grown with conventional direct current magnetron sputtering (dcMS) and for the first time, using a high power impulse magnetron sputtering (HiPIMS) process. Surface morphology and depth profile reveal that HiPIMS deposited film has the lowest roughness, the highest packing density and the sharpest interface. La from the LAO substrate and Fe from the film interdiffuse and forms an undesired interface spreading to an extent of about 10-20 nm. In the HiPIMS process, layer by layer type growth leads to a globular microstructure which restricts the extent of the interdiffused interface. Such substrate-film interactions and microstructure play a vital role in affecting the electronic hybridization and magnetic properties of Fe4N films. The magnetic moment (Ms) was compared using bulk, element-specific and magnetic depth profiling techniques. We found that Ms was the highest when the thickness of the interdiffused layer was lowest and only be achieved in the HiPIMS grown samples. Presence of small moment at the N site was also evidenced by element-specific x-ray circular dichroism measurement in HiPIMS grown sample. A large variation in the Ms values of Fe4N found in the experimental works carried out so far could be due to such interdiffused layer which is generally not expected to form in otherwise stable oxide substrate. In addition, a consequence of substrate-film interdiffusion and microstructure results in different kinds of different kind of magnetic anisotropies in films grown using different techniques.