CrN Layers Research Articles

Micromechanical investigation of DLC based coating systems by means of combined characterization and simulation methods

The assessment of the elastic-plastic material behavior is imperative for benchmarking the performance of thin coating systems. Linear-elastic approaches can lead to deviating results and experimental investigations, such as fatigue tests, frequently overlook the intricacies of the failure mechanism. Therefore, the elastic-plastic material behavior of DLC based coating systems with CrN support interlayer, deposited on 100Cr6 substrates and Si, was investigated. Using an inverse approach, a nanoindentation simulation with spherical indenter geometry was iteratively optimized to experimental curves by adjusting the material parameters Young's modulus E, yield strength Y, hardening coefficient K and hardening exponent n for DLC and CrN layers. Mechanical parameters were measured and the yield strength of DLC was analyzed with a scratch procedure to implement appropriate initial values. The results showed an overall good agreement between the measured and optimized force-displacement curves with reasonable determined material parameters. The control parameter Y exhibited nearly identical outcomes for scratch measurements and the calculated value from simulations although DLC was deposited on different substrates. The employment of a spherical indenter tip mitigates the influence of the microstructure in the CrN layer through homogenization effects and a larger affected area of the plastic zone. Furthermore, enhancing the performance of the coating systems can be achieved by increasing the DLC or CrN interlayer thickness.

The effect of roughness and top layer in solid particle impingement erosion of multilayer nanostructured nitride PVD coatings

The effect of the surface roughness of the coating and the composition of the upper layer on the solid particle erosion of multilayer nanostructured coatings applied via cathodic arc evaporation (CAEPVD) method was investigated. CrN/TiN nanostructured multilayer coating (TiN as the upper layer) and TiN/CrN nanostructured multilayer coating (CrN as the upper layer) were applied on 410 stainless steel through the CAEPVD method with the following architecture. 1) a bottom layer of Cr and CrN deposited on the substrate, 2) nanolayers of TiN and CrN deposited on the bottom layer alternately and 3) an upper layer of CrN or TiN deposited on the nanolayers. After applying the coating, half of the samples were polished to obtain smooth surfaces, while the other half remained unpolished, resulting in rough surfaces. Surface morphology, phases identification, adhesion, mechanical, and erosion behavior of the coatings were characterized using SEM, XRD, Rockwell adhesion measurements, nanoindentation test, and solid particle impingement, respectively. The nano-scale indentation results demonstrated that the hardness, Young's modulus, H/E, and H3/E2 of the CrN/TiN coating were 5.57, 1.42, 3.86, and 85.39 times larger than those of the substrate. For the TiN/CrN coating, the values were 4.04, 1.13, 3.53 and 51.68 times greater than those of the substrate. The results of the erosion test showed that the erosion mass loss for the CrN/TiN and TiN/CrN coatings decreased up to 73% and 67%, respectively. Additionally, surface smoothing improved erosion resistance by 40% for both coatings. This shows that the smoothed CrN/TiN nanostructured multilayer coating is an excellent candidate for increasing the erosion resistance due to the higher ratios of H/E and H3/E2 and smoother surface.

Influence of Multilayer Structure on the Structural and Mechanical Properties of TiAlN/CrN Coatings for Advanced Machining Applications

This study investigates single and multilayer TiAlN/CrN nanocomposite thin films developed using an RF magnetron sputtering system. The TiAlN and CrN layers showed a high degree of orientation, with the (200) peak being the strongest peak in both layers, and a multilayer structure was clearly observed. The surface roughness analysis using atomic force microscopy (AFM) and cross-sectional transmission electron microscopy (TEM) revealed that the TiAlN/CrN coatings had a smoother surface than the single-layer coatings and minimal intermixing between the two layers. Depth-sensing indentation measurements were used to measure the hardness and Young’s modulus of the coatings, demonstrating that TiAlN/CrN coating had the highest hardness (~16.38 GPa) and elastic modulus (~3.82 GPa) among all the coatings studied. This indicates that the TiAlN/CrN multilayer coating possesses superior mechanical properties due to its interface strength. Our findings suggest that these multilayer coatings have potential applications in tribological and decorative coatings.

Evaluating the corrosion and tribological performance of nanostructured CrN/TiN and TiN/CrN configurations applied on 410 stainless steel

ABSTRACT This study aims to compare the corrosion and tribological performance of TiN/CrN and CrN/TiN nanostructured multi-layer coatings deposited through cathodic arc evaporation PVD on 410-grade stainless steel. Both coating configurations were available in smooth (polished) and rough states. For the deposition of multi-layer coatings, a middle layer containing Cr and CrN was deposited to the substrate, followed by alternating nanolayers of TiN and CrN. finally, an upper layer of either CrN or TiN was applied. The nanoindentation test revealed that the hardness, Young’s modulus, H/E, and H3/E2 ratios of the coating with a TiN upper layer were 5.57, 1.42, 3.86, and 85.39 times of the substrate, respectively. At the coating with CrN upper layer, these values were 4.04, 1.13, 3.53, and 51.68 times of the substrate, respectively. Results showed that increasing the H/E and H3/E2 ratios increased wear resistance. Wear rates of smooth and rough TiN coatings and smooth and rough CrN coatings were reduced by 86%, 99%, 53%, and 26%, respectively, compared to the substrate. Results of the corrosion test showed that the rough CrN coating had greater corrosion resistance than the coating with a TiN upper layer and the substrate due to its higher hydrophobicity.

Improving the corrosion and wear resistance of CoCrNiSi0.3 Medium-Entropy Alloy by magnetron sputtered (CrN/Cr)x multilayer films

In this study, a medium entropy alloy (MEA) system consisting of Co, Cr, and Ni was selected to incorporate Si, resulting in the creation of CoCrNiSi0.3 MEA. The surface was coated with (CrN/Cr)x multilayer films to improve wear and corrosion resistance. The hardness, wear, corrosion, and nanoindentation tests were used to analyze the characteristics of CrN/Cr multilayer films and their protective performance. Low grazing angle X-ray diffraction (GIXRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), water contact angle analyzer, and transmission electron microscopy (TEM) were utilized to investigate the composition and structure of (CrN/Cr)x multilayer films. The intermediate Cr layer inhibits the columnar growth of the CrN layers and is progressively refined as the number of CrN/Cr bilayers increases. The Cr layer exhibits superior toughness in the multilayer structure and effectively hinders crack propagation. Therefore, the (CrN/Cr)3 multilayer film has the most outstanding anti-wear performance. The wear rates under 2 N and 4 N loads are 3.331 × 10−6 mm3•m−1•N−1 and 1.124 × 10−5 mm3•m−1•N−1, respectively. The growth of columnar crystals is suppressed and a more compact multilayer film is formed, resulting in a reduction in the defect density and an increase in the water contact angle, which retards the ingress of corrosive liquid and improves corrosion resistance. The corrosion current density of the (CrN/Cr)3 multilayer film is 0.73 μA•cm−2, while the corrosion polarization impedance is 962.35 Ω•cm2.

Spin valve effect in CrN/GaN van der Waals heterostructures

In the pursuit of developing high-performance low-dimensional spintronic devices, two-dimensional van der Waals heterostructures comprising non-magnetic nitride and ferromagnetic materials have emerged as a crucial area of investigation. This paper proposes a novel structure that employs hexagonal two-dimensional semiconductor GaN flanked by two half-metallic two-dimensional CrN layers. The stability of the proposed structure is verified via first-principles calculations, which indicate good thermodynamic and magnetic stability. The transport characteristics of electrons in the structure are analyzed through the Band structures and density of states. Specifically, the study examines the spin polarizability of parallel and anti-parallel magnetic configurations of the CrN/GaN/CrN vdW heterostructure, and the results demonstrate a significant spin valve effect. Overall, the study establishes the potential of the CrN/GaN/CrN vdW heterostructure as a candidate for the development of innovative spintronic devices.

Microstructural understanding of CrN layer as a barrier against Cr-Zr interdiffusion in Cr-coated zirconium alloy for accident tolerant fuel claddings

In this study, a Cr-CrN-Cr coating was fabricated on Zr alloy to explore the barrier effect of the CrN layer on Cr-Zr interdiffusion. Steam oxidation tests were conducted using both a thermogravimetric analyzer and a tube furnace to examine the oxidation resistance and coating evolution of the sample under high-temperature conditions. Atomic scale characterizations were performed on the sample after exposure. After HT annealing, a ZrN layer composed of nano equiaxed grains was successfully formed between the residual coating and Zr substrate, serving as a diffusion barrier for both the Cr-Zr interdiffusion and nitrogen/oxygen inward diffusion. Nano twin crystals were observed within the ZrN grains, and the growth of twin boundaries was along multi-directions. The coating evolution during HT annealing was analyzed, and the impact of ZrN layer on the inhibition of Cr-Zr interdiffusion was discussed.

CrN–NbN nanolayered coatings for enhanced accident tolerant fuels in BWR

The accident tolerant fuel (ATF) concept has emerged in the years after the 2011 Fukushima accident as part of a renewed effort in research for light water reactors. The primary focus is to further improve safety measures under and beyond design basis accident conditions, and to improve fuel cladding performance in normal operation. The application of a coating on zirconium claddings can achieve both these aims without extensive changes to the reactor design. Metallic chromium coatings have been profusely studied as solution for pressurized water reactors, but the search for an effective ATF coating able to withstand the environment inside boiling water reactors (BWRs) is still ongoing. In this work, two different versions of a novel nitride coating composition were studied. Zirconium claddings coated with 8 µm thick layers of superlattice CrN–NbN and a nanolayered CrN–NbN were tested in autoclave under BWR operating conditions for 60 days. Scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy, electron back-scattered diffraction, x-ray diffraction, and atom probe tomography were employed to characterize as-deposited and autoclaved samples of these two materials. During exposure, both coating versions formed a stable, dense and passivating oxide scale (200–300 nm thick) on the surface, demonstrating improved oxidation protection under operating conditions. Some differences in the oxide growth mechanism were observed between the superlattice and the nanolayered CrN–NbN coatings, which allowed to glimpse at the effect of the layer thickness on the oxidation protection provided by these coatings. The nano-structured morphology of both coatings remained unaffected by the autoclave test, but a 35 nm thick Zr-Cr-N phase was found at the coating-substrate interface of the superlattice CrN–NbN coated cladding.

Effect of Adding Intermediate Layers on the Interface Bonding Performance of WC-Co Diamond-Coated Cemented Carbide Tool Materials.

The interface models of diamond-coated WC-Co cemented carbide (DCCC) were constructed without intermediate layers and with different interface terminals, such as intermediate layers of TiC, TiN, CrN, and SiC. The adhesion work of the interface model was calculated based on the first principle. The results show that the adhesion work of the interface was increased after adding four intermediate layers. Their effect on improving the interface adhesion performance of cemented carbide coated with diamond was ranked in descending order as follows: SiC > CrN > TiC > TiN. The charge density difference and the density of states were further analyzed. After adding the intermediate layer, the charge distribution at the interface junction was changed, and the electron cloud at the interface junction overlapped to form a more stable chemical bond. Additionally, after adding the intermediate layer, the density of states of the atoms at the interface increased in the energy overlapping area. The formant formed between the electronic orbitals enhances the bond strength. Thus, the interface bonding performance of DCCC was enhanced. Among them, the most obvious was the interatomic electron cloud overlapping at the diamond/SiCC-Si/WC-Co interface, its bond length was the shortest (1.62 Å), the energy region forming the resonance peak was the largest (-5-20 eV), and the bonding was the strongest. The interatomic bond length at the diamond/TiNTi/WC-Co interface was the longest (4.11 Å), the energy region forming the resonance peak was the smallest (-5-16 eV), and the bonding was the weakest. Comprehensively considering four kinds of intermediate layers, the best intermediate layer for improving the interface bonding performance of DCCC was SiC, and the worst was TiN.

Study of the structure, structural transition, interface model, and magnetic moments of CrN grown on MgO(001) by molecular beam epitaxy

Structural phase transition is studied in high quality CrN thin films grown by molecular beam epitaxy on MgO(001) substrates. Cross-sectional transmission electron microscopy and x-ray diffraction reveal that the epitaxial relationship between CrN film and MgO substrate is [100]CrN/[100]MgO, [110]CrN/[110]MgO, and [001]CrN/[001]MgO. The films show tensile strain/compression at the CrN/MgO(001) interface, which relaxes gradually with the film growth. Temperature dependent x-ray diffraction measurements show a first-order structural phase transition. In addition to the experimental measurements, first-principles theoretical calculations have been carried out for finding a stable model for the CrN/MgO interface. These calculations determine two possible models for the interface, where a monolayer of chromium oxide is formed between the CrN and MgO layers.

In-vitro corrosion and surface properties of PVD-coated β-type TNTZ alloys for potential usage as biomaterials: Investigating the hardness, adhesion, and antibacterial properties of TiN, ZrN, and CrN film

In this study, the corrosion and surface properties of non-toxic and non-allergenic β-type Ti–29Nb–13Ta–4.6Zr alloys (TNTZ) coated with TiN, ZrN, and CrN layers using the PVD technique were investigated under in-vitro conditions. The coatings' hardness, adhesion resistance, and antibacterial properties were also studied, with a focus on their potential usage as biomaterials. The corrosion tests were conducted using potentiodynamic polarization, the hardness tests were conducted using the Knoop method, and the adhesion tests were conducted using pull-off tests. The wetting properties of the coatings were examined through contact angle and 3D morphological analysis. The coatings were characterized using SEM-EDS and XRD. The results showed that the adhesion resistance of all coatings was significantly higher than the expected adhesion strength for biomaterial coatings, while their corrosion resistance was higher compared to the uncoated alloy. Besides, the study demonstrates the potential of TiN, ZrN, and CrN coatings on β-type TNTZ for use as a biomaterial with desirable surface and antibacterial properties.

The post‐annealing effect on tribological and corrosion behaviors of CrN/AlCrN multilayered coating applied by CAE‐PVD

AbstractThe present study investigated the wear and electrochemical behaviors of CrN/AlCrN multilayered coatings post‐annealed at 300, 450, and 600°C temperatures. The cathodic arc evaporation technique has been utilized to deposit the coatings. Scanning electron microscope, field emission SEM, energy‐dispersive X‐ray, grazing incidence X‐ray diffraction, and Rockwell‐C indenter methods were used to characterize the coatings and to investigate the interdiffusion between the multilayered CrN/AlCrN and the H13 base metal. The results showed that the sharp interface of the CrN and AlCrN layers was blurred by the annealing process supporting the interdiffusion of the layers. The reciprocating wear test and the microhardness tester were used to evaluate the coatings’ mechanical behavior. The hardness and roughness of the coatings were increased by increasing the post‐annealing temperature. The smallest wear rates were observed for the samples treated at 300 and 450°C, which were approximately 17 times and 12 times smaller than the wear rate of the sample annealed at 600°C. Electrochemical testing was used to study the corrosion behavior of the coatings. The results showed that by increasing annealing temperature, corrosion resistances of the coatings are improved. As a result, the corrosion current density of the 600°C annealed coating was approximately 434 times smaller than as‐deposited coatings.

Interface feature via key factor on adhesion of CrN multilayer and alloy substrate

CrN multilayer coatings were deposited on 316L stainless steel, which has a high modulus, and TC4 titanium alloy, which exhibits the opposite properties, to reveal adhesion mechanisms and deformation behavior of the coating/substrate systems. Because of the different microstructures, the coatings’ morphologies varied from single polygon on the 316L to polygon and rectangle-mixed shapes on the TC4. On 316L, the cracks initiated from the Cr/CrN interfaces and propagated into the CrN layer, which stopped within it. On TC4, the cracks propagated through the CrN layer. The coherent nanocrystal interfaces in CrN/Cr/316L exhibited orderly bending, revealing the presence of strong interfacial bonds. The undeformed interfaces in CrN/Cr/TC4 indicated incompatible deformation and weak bonds. This was consistent with the fact that on TC4, the Cr/CrN interface tensile stress was high, at 123.1 GPa, while it was lower on 316L, at 99.3 GPa. The Wp/We ratio of CrN/TC4, namely 1.94, was lower than that of CrN/316L, namely 2.61. This indicated that CrN/316L had a high energy-absorption ability because of compatible plastic deformation. The failure mechanism observed between the coating/TC4 was attributed to the differences in their moduli, which led to incompatible deformation, high interfacial tensile stress, and low absorption capability for external work.

Effect of Plasma Nitriding and Oxidation on the Corrosion Resistance of 304 Stainless Steel in LiBr/H2O and CaCl2-LiBr-LiNO3-H2O Mixtures

The effect of plasma nitriding and oxidation on the corrosion resistance of AISI 304 type stainless steel in LiBr/H2O and CaCl2-LiBr-LiNO3-H2O mixtures at 80 °C has been evaluated by using potentiodynamic polarization curves and electrochemical impedance spectroscopy techniques (EIS). Steel was plasma treated at 500 °C during 8 h under different atmospheres, nominally 20% N2 + 80% H2, 100% N2 and 100% O2. X-ray diffraction analysis (XRD) showed the presence of a CrN layer in nitrided specimens, whereas scanning electronic microscopy analysis revealed that specimen treated in the 20% N2 + 80% H2 atmosphere showed the thickest nitride layer. Specimens nitrided in the 20% N2 + 80% H2 atmosphere had the noblest open circuit potential value in both solutions, whereas potentiodynamic polarization curves indicated the formation of a passive layer. These specimens exhibited the lowest corrosion and passivation current density values. Corrosion process was under charge transfer control in both solutions regardless of the plasma treatment. The type of corrosion suffered by the steel under all treatments was the pitting type of corrosion. Pits density was the lowest for nitrides steels rather than that for untreated or pre-oxidized ones.

Achieving high tribological and corrosion performances via a new approach: Al2O3/CrN duplex coatings

Owing to growth defects, the CrN coating–substrate system may suffer from severe corrosion and wear attack in a marine environment, which limits the coating protection against the 316L substrate. To improve the efficiency, a new approach of fabricating Al2O3/CrN duplex coatings to achieve excellent corrosion and wear performances was provided by sealing the growth defects and extending the deposition time of the CrN layer. The Al2O3/CrN duplex coatings were obtained by multi-arc ion plating system sputter CrN layers combined with sequential atomic layer deposition Al2O3 layers. The morphology and structure of the as-deposited coating were investigated by scanning electron microscopy and x-ray photoelectron spectroscopy. The corrosion performances and tribological properties of the Al2O3/CrN duplex coatings in a seawater environment were investigated. The results showed that the density of the duplex coating decreases as the CrN layer thickness increases. The Al2O3/CrN duplex coatings with a suitable CrN layer thickness exhibited superior corrosion resistance in a seawater environment, which may be ascribed to the Al2O3 layer filling or sealing the partial growth defects of the CrN layer and playing a good barrier role to prevent the infiltration and penetration of corrosive media. Furthermore, the wear rate of the Al2O3/CrN duplex coating was reduced more than 30% compared to the single CrN coating of the same thickness. The good wear resistance of Al2O3/CrN duplex coatings was attributed to the synergistic effect of the dense structure, high wear resistance of the Al2O3 layer, and the supporting effect of the CrN layer as well as the formation of the lubricating component of CaCO3 and Mg(OH)2 during wear progress.

Structure and Properties of CrN/TiN Multi-Layer Coatings Obtained by Vacuum-Arc Plasma-Assisted Deposition Method

The paper presents the study results of CrN/TiN multi-layer coatings, as well as single-layer TiN and CrN coatings on Cr12MoV cold work die steel deposited by the vacuum-arc plasma-assisted method. Three CrN/TiN coatings of 8-, 16-, and 32-layers were deposited, in which the thickness of each layer was 500 nm, 250 nm and 125 nm, respectively. All of the coatings reveal a face-centered cubic structure with highly oriented (111) growth. The hardness of the CrN/TiN multi-layer coatings was about 27 GPa. Changing the architecture of CrN/TiN multi-layer coatings by reducing the thickness of the CrN and TiN layers from 500 nm to 125 nm promotes a smooth decrease in both the wear parameter and the coefficient of friction. By using an X-ray phase analysis with synchrotron radiation, it was found that 32-layer CrN/TiN coating retained thermal stability during heating in air to a temperature of 1120–1125 °C, and in a vacuum at least to a temperature of 1200 °C.

Restraining the Cr-Zr interdiffusion of Cr-coated Zr alloys in high temperature environment: A Cr/CrN/Cr coating approach

In this study, a Cr-CrN-Cr coating was fabricated on Zr alloys to restrain the Cr-Zr interdiffusion of Cr-coated Zr alloys. The early stage diffusion, decomposition, and oxidation behaviors of the coating sample are investigated by a tube furnace equipped with a “fast-in & fast-out” tool. The outer and inner Cr layer was transferred into Cr2N by nitrogen, which was formed by the decomposition of the CrN layer. A Zr2N layer formed at the interface between the residual coating and Zr substrate, which acted as a diffusion barrier. After oxidation in a steam environment, the coating structure can be divided into Cr2O3, CrN, Cr2N, and Zr2N (from outside to inside).

Hydrogen protection using CrN coatings: Experimental and theoretical study

Preventing hydrogen damage is an important issue in materials design. To prevent such damage, CrN coating is investigated as a very promising candidate for hydrogen damage protection. In this study, the theoretical analysis of hydrogen adsorption on CrN surfaces was studied. It was found that most CrN surfaces are inert to hydrogen and do not adsorb it. This finding is suggested to explain the hydrogen protection caused by these coatings. To demonstrate these abilities of CrN coatings, we used the Pulsed-DC magnetron sputtering method to produce CrN layers on gadolinium substrates. The coated samples were exposed to hydrogen, characterized by SEM, XRD, and GD-OES, and show no hydrogen damage, were the uncoated ones exhibited a massive hydrogen attack.

The preparation and lubrication properties of a CrN/Cr multilayer using the double glow plasma surface alloying technique

Metal sealing rings with high hardness can improve wear resistance and reduce internal leakage. In this study, the double glow plasma surface alloying (DGPSA) technique was employed to produce the necessary conditions for a metallurgical bond and lubricant storage. Four primary stages are required in deposition processing: evaporation, destruction, atomization, and ionization. A Cr layer (including a 5 μm interdiffusion layer and a 45 μm pure metallic layer in thickness) and a thin (1–2 μm) CrN layer were prepared using the DGPSA technique. The obtained interdiffusion layer can reduce the mismatch in mechanical properties between the Cr layer and the substrate. When the atomic coverage of N atoms is higher than 1.5 ML, the stable adsorption structure is essentially nonexistent, indicating that improving the N2 ionization rate is more valuable than increasing the nitrogen partial pressure. When the Ar/N2 flow ratio is 2:1, the CrN/Cr multilayers provided microreservoirs for lubricants and improved wear and plastic deformation resistance. For the CrN/Cr multilayer, a higher contact pressure resulted in superior frictional properties.

Manufacture of Wear-Resistant Alloy Co-Cr-Mo for Medical Implant Applications by Nitriding Coating Method

Nitrogen doped as-cast Co-Cr-Mo alloy with markedly enhanced hardness and wear resistance was successfully produced by pack nitriding process. Nitriding proses used the in-pack process using urea fertilizer as a nitrogen source. It was carried out with variations in temperature of 400°C, 500°C, 600°C and followed by annealing. The wear resistance of the specimen is tested using pin-on-disk. The total sample will be soaked in the lactic acid solution for 3 days. The results obtained from the After nitriding process, the hardness of of speciment N400 obtained a hardness value of 261.54 HV speciment N500 of 309.68 HV, and speciment N600 of 429.14 HV, the results of the hardness value increased in each speciment. The wear resistance value obtained for each speciment N400, N500, N600 is 2,81 x 10-6 mm3/Nm, 7,50 x 10-7 mm3/Nm, 1,87 x 10-7 mm3/Nm. The nitriding process forms a layer on the surface of the as-cast Co-Cr-Mo, it’s called Layer of Cr-N which is the result of heating/decomposing urea fertilizer into nitrogen gas which can coat the surface so that Cr-N bonds are formed in the layer. The thickness of the Cr-N layer on the N400 specimen is 0.28 mm, N500 is 0.35 mm, N600 is 0.38 mm. In addition, the surface results that have been tested for wear resistance form quite fine scratches but the formation of abrasions, such as abrasion, abrasion groove, delamination, and cohesive failure