Microstructure, mechanical, and tribological properties of transition metal (Nb, V, W) nitride coating on AISI-1045 steel by cathodic cage plasma deposition

Improvement in surface properties of AISI-5160 steel by transition metal (Nb, V) nitride coating through cathodic cage plasma deposition

In this study, a cathodic cage plasma deposition (CCPD) system equipped with a vanadium cathodic cage is used to deposit vanadium nitride coating on AISI-420 steel. This study aims to improve the tribological and mechanical properties. Specifically, this system is used because it can deposit not only a hard coating but also form a nitrogen diffusion layer that can enhance the load-bearing capacity of the sample and coating adhesion with the substrate. The XRD shows that vanadium nitride (VN) coating is polycrystalline, with a favored orientation along the (200) plane. The SEM results depict that at 673 K, the surface consists of uniformly disseminated spherical nanoparticles agglomerate to form coralloid granular nitrides. At 723 K, polygonal particles are uniformly distributed over the entire surface. The thickness of vanadium nitride films is 0.6 and 1.1 μm for 673 K and 723 K temperatures. The hardness of the sample increased up to 3 times over the untreated sample, whereas mechanical properties, including elastic modulus, and hardness-elastic modulus ratios H/E,H2/E,H3/E2 are upgraded, specifically at 723 K. Remarkably, the wear rates are reduced more than ten times, and a significant decrease in friction coefficient due to the deposition of VN coating. After the ball-on-disc wear analysis, the wear track is smooth and narrow for coated samples and still covered with vanadium and nitrogen elements, which indicates deposited coating is not detached from the substrate. It shows that VN coating can be deposited effectively to enhance the mechanical and tribological properties of AISI-420 steel.

Recent advances in pseudocapacitor electrode materials: Transition metal oxides and nitrides

The fabrics with copper or copper oxide deposition are of considerable interest because of exceptional antibacterial properties, which are useable in medical, textiles, and hygiene applications. Unfortunately, the conventional techniques take long processing time, complex equipment, and combination of several processing steps (nanoparticles synthesis and their deposition on fabrics). In this novel study, cathodic cage plasma deposition assisted with copper cathodic cage is used for the synthesis of the copper oxide on polyester and polyamide fabrics. For the enhancement of synthesis efficiency, the effect of cathodic cage lid thickness is also investigated. The samples are assessed by using scanning electron microscopy, elemental dispersive spectroscopy, and X‐ray photoelectron spectroscopy. It is found that using cathodic cage plasma deposition, fabrics can be successfully synthesized by the copper oxide with comparatively small treatment time, cost‐effectively, and environmentally friendly. Interestingly, cathodic cage plasma treatment is already proved to be working effectively on industrial scale; thus, it is predicted to be of noteworthy importance for fabrics processing on large‐scale garments manufacturing and hospitals.

Combined plasma treatment of AISI-1045 steel by hastelloy deposition and plasma nitriding

Synthesis of molybdenum oxide on AISI-316 steel using cathodic cage plasma deposition at cathodic and floating potential

Nitrides of 3d ferromagnetic metals (Fe, Co and Ni) or transition metal nitrides (TMNs) appearing late (Group 8–10) in the 3d series are emerging compounds in a wide range of areas such as spintronics, magnetic devices, hard coatings, catalysts for hydrogen and oxygen evolution reaction for electrochemical water splitting, ion batteries, high energy density materials, etc. Some of these TMNs can be synthesized using non-equilibrium processes such as physical vapour deposition or under extremely high pressure and high temperatures. Thermodynamical constraints arisen due to high enthalpy of formation not only make the synthesis of late TMNs difficult, but also thus formed TMNs are also metastable. The thermal stability of late TMN is closely related to metal and nitrogen self-diffusion processes. We performed both Fe and N self-diffusion measurements in various Fe-N compounds and also explored ways to control it through effective dopants. It was found that in magnetic Fe-N compounds (N\({at.}\)% < 25\(\%\)), N self-diffusion is orders of magnitude faster than Fe, but in non-magnetic Fe-N compounds (N\({at.}\)% \(\approx \)30 and 50\(\%\)), it was surprisingly found to be the other way round. The mechanism related to self-diffusion processes in different Fe-N phases is presented and discussed. This chapter is divided into five sections. In Sect. 1, after a brief introduction of TMNs, different phases and the structure of iron nitrides have been discussed with a brief timeline and applications. Synthesis of different iron nitride thin films using reactive sputtering process, their thermal stability and the effect of dopant on the thermal stability is presented in Sect. 2. Section 3 presents methods and techniques for self-diffusion measurements. In Sect. 4, detailed self-diffusion measurements in magnetic as well as non-magnetic Fe-N compounds are given and also the effect of dopants on self-diffusion process is discussed. This chapter ends with conclusions presented in Sect. 5.

SAE 5160 steel, classified as high-strength, low-alloy steel, is widely used in the automotive sector due to its excellent mechanical strength and ductility. However, its inherently low corrosion resistance limits its broader application. This study explores the application of the cathodic cage plasma deposition (CCPD) technique to enhance the corrosion resistance of SAE 5160 steel. The treatment was performed using a Hastelloy cathodic cage under two atmospheric conditions: hydrogen-rich (75%H2/25%N2) and nitrogen-rich (25%H2/75%N2). Comprehensive analyses revealed significant improvements in surface properties and corrosion resistance. The hydrogen-rich condition (H25N) facilitated the formation of Cr0.4Ni0.6 and CrN phases, associated with a nanocrystalline structure (37.6 nm) and a thicker coating (45.5 μm), resulting in polarization resistance over 290 times greater than that of untreated steel. Conversely, nitrogen-rich treatment (H75N) promoted the formation of Fe3N and Fe4N phases, achieving a dense but thinner layer (19.6 μm) with polarization resistance approximately 20 times higher than that of untreated steel. These findings underscore the effectiveness of CCPD as a versatile and scalable surface engineering technique capable of tailoring the properties of SAE 5160 steel for use in highly corrosive environments. This study highlights the critical role of optimizing gas compositions and treatment parameters, offering a foundation for advancing plasma-assisted technologies and alloying strategies. The results provide a valuable framework for developing next-generation corrosion-resistant materials, promoting the longevity and reliability of high-strength steels in demanding industrial applications.

Improved wear resistance of AISI-4340 steel by Ti–Nb–C–N and MoS2 composite coating by cathodic cage plasma deposition

The electrochemical carbon dioxide reduction reaction (CO2RR) to produce synthesis gas (syngas) with tunable CO/H2ratios has been studied by supporting Pd catalysts on transition metal nitride (TMN) substrates. Combining experimental measurements and density functional theory (DFT) calculations, Pd‐modified niobium nitride (Pd/NbN) is found to generate much higher CO and H2partial current densities and greater CO Faradaic efficiency than Pd‐modified vanadium nitride (Pd/VN) and commercial Pd/C catalysts. In‐situ X‐ray diffraction identifies the formation of PdH in Pd/NbN and Pd/C under CO2RR conditions, whereas the Pd in Pd/VN is not fully transformed into the active PdH phase. DFT calculations show that the stabilized *HOCO and weakened *CO intermediates on PdH/NbN are critical to achieving higher CO2RR activity. This work suggests that NbN is a promising substrate to modify Pd, resulting in an enhanced electrochemical conversion of CO2to syngas with a potential reduction in precious metal loading.

1. The addition of vanadium and niobium nitrides to pure iron inhibits austenite grain growth, increasing the temperature at which the process occurs. Niobium nitride inhibits grain growth more than vanadium nitride. This is explained by its higher thermal stability. 2. Grain growth in alloys containing vanadium nitride occurs mainly by the mechanism of "fusion," and in alloys with niobium nitride by the migration mechanism. This is also due to the more rapid solution of vanadium nitride (compared with niobium nitride) and its elimination from the grain boundaries.

Chapter 5 - Refractory plasmonic materials

Titanium nitride (TiN) is a good choice for the improvement in surface hardness of high-speed steel. Unfortunately, it has low adhesion with substrate and exhibits high friction coefficient; as a result it does not provide sufficient protection against sliding wear in metal-to-metal contact. The adhesion problem can be removed by nitriding process, whereas friction coefficient can be reduced by solid lubrication coating. In this study, an attempt is made to synthesize TiN hard coating as well as solid lubrication coating of molybdenum disulfide (MoS2) using magnetron sputtering, along with substrate pre-treatment by cathodic cage plasma deposition using titanium cathodic cage. The cathodic cage plasma nitrided sample exhibits significantly higher surface hardness, which reduced by solid lubrication coating. The nitrided sample depicts the presence of iron nitrides, TiN and nitrogen diffused martensite phases, whereas coated samples shows the presence of MoS2 and TiN phases. The friction coefficient and machining temperature are dramatically reduced by lubrication coating. This study recommends that the use of cathodic cage plasma nitriding using titanium cathodic cage is beneficial for improved surface hardness, and addition of solid lubrication coating is beneficial for reducing the coefficient of friction and machining temperature by scarifying hardness. As, both the systems are already proven to be appropriate for industrial-scale uses, thus results from this study can be applied for industrial-scale application.

The family of two-dimensional (2D) materials-solids with high aspect ratios and thicknesses consisting of a few atomic layers-has grown far beyond graphene. 2D transition metal carbides, nitrides and carbonitrides, known as MXenes, are one of the latest additions to this family. This rapidly growing class of 2D materials finds applications in fields ranging from energy storage to electromagnetic interference shielding and transparent conductive coatings. However, while over twenty carbide MXenes have been synthesized, very few transition metal nitrides (TMNs), and no nitride MXenes, had previously been reported. Two-dimensional TMNs, including nitride MXenes, have several potential advantages over their carbide analogs. They theoretically have higher values of electrical conductivity than carbide MXenes, which has implications on outperforming carbides in electrochemical and other applications. Compared to carbides, they are superior candidates for promising plasmonic devices and spintronic devices that incorporate magnetic 2D materials. Although there are theoretically as many nitride MXenes as carbide MXenes predicted, synthesizing nitride MXenes and 2D TMNs in general faces several challenges. Synthesis methods that have produced over two dozen 2D carbides MXenes have failed to yield 2D TMNs. The major focus of this dissertation is investigating routes of synthesizing 2D TMNs including, but not limited to, selective etching of layered bulk metal nitride precursors. Three promising routes of synthesis are explored, and their electronic and magnetic properties of the synthesized materials are also characterized. Discovering how to synthesize 2D TMNs will remove the barrier between merely studying their theoretically predicted properties and finally applying these outstanding properties in devices for energy storage, spintronics and beyond.

Due to their high hardness, high melting point and high chemical stability, transition metal nitrides present a great interest for various applications. This work constitutes a contribution to the understanding of the properties of Nb based binary and ternary nitride materials. It deals with the study of the deposition and characterization of the niobium nitride system. Single and mixed phase thin films of niobium nitride in addition to niobium silicon nitride and niobium aluminum nitride were deposited by DC reactive magnetron sputtering. The properties of these thin films are investigated using several experimental techniques: X-ray diffraction, scanning and transmission electronic microscopy, optical reflectivity and spectroscopic ellipsometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, electrical measurements and nanoindentation. The influence of the nitrogen partial pressure and substrate temperature on the phase composition is studied. Single and mixed phase of niobium nitride films: β-Nb2N, δ-NbN and δ'-NbN were successfully deposited. The single phase niobium nitride films are characterized. Properties of mixed phase films are interpreted in the light of that of single phase. All NbN thin films have a columnar morphology. The columnar structure in the hexagonal phases is more pronounced than in the cubic. The hexagonal δ' and β phases are more covalent than the cubic one. The physical parameters (carrier charge density N* and free electron relaxation time τ) for each single phase were calculated by fitting the optical properties using a Drude model with a set of Lorentz oscillators. High hardness values of 35 and 40 GPa are measured for the β and δ' phases, respectively. They are larger than that of the cubic δ phase, 25 GPa. This hardness values is related to the high covalent character of the hexagonal phases compared to that of the cubic. Hardness of mixed phase is determined by the hardness of the majority phase. Influence of the addition of a third element, Si and Al, into NbN is studied. Nb-Si-N and Nb-Al-N thin films were deposited and characterized. A model for the film formation of Nb-Si-N thin films deposited by DC magnetron sputtering is proposed. Three distinct concentration domains were pointed out. In Domain 1 (1 ≤ CSi ≤ 4 at.%) the Si atoms substitute Nb in the NbN lattice and polycrystalline films of NbN:Si are deposited. In Domain 2 (4 ≤ CSi ≤ 7 at.%) a fraction of Si atoms segregates to the grain boundaries. A SiNx layer forms on the NbN:Si crystallite surfaces. The covering ratios increase with Si content up to 100% (formation of a monolayer). For further increase of Si content (Domain 3), the NbN:Si crystallites, surrounded by a monolayer of SiNx, reduce their size from 18 to 2 nm. The increasing amount of the SiNx phase in the films is realized by increasing the surface to volume ratio of the NbN:Si nanocrystallites. The formation of the SiNx layer explains the change observed in the electrical and optical properties of Nb-Si-N films with increasing the Si content. The electrical resistivity measured as a function of temperature is proposed to provide an experimental mean for determining the limit of Si solubility in the Nb-Si-N system and for following the thickness evolution of the SiNx coverage layer in the composite films. For NbzAlyNx films, the solubility limit of the Al in the NbN lattice is in the range: y/(y+z) = 0.5±0.1. Passing this value an insulating hexagonal AlNx phase is formed. The electronic properties of the NbzAlyNx are significantly altered by the changes in the value of y and x. The resistivity increases with increasing y. The hardness of NbzAlyNx is maximum in films with y = 0.19 (solubility limit). At higher y the formation of the AlNx phase reduces the hardness. The increase of hardness observed in the NbzAlyNx films is attributed to the solid solution hardening mechanism. If the system NbN presents many phases, it appears that the addition of a third element, Si and Al, allows the stabilization of the cubic δ phase. In both Nb-Si-N and Nb-Al-N systems Si and Al are soluble up to a certain limit. Passing this limit the third element segregates at the grain boundaries forming SiNx and hexagonal AlNx. If in the case of Nb-Si-N, the formed SiNx cannot be detected by X-ray diffraction due to the fact that it segregates as a thin layer at the grain boundaries of the NbN grains. In the case of the Nb-Al-N the hexagonal AlNx phase is clearly detected. The high Al solubility in the Nb-Al-N gives rise to a large change of the electronic properties with increasing the Al content.