CrAlN Coatings Research Articles

Design and Corrosion Resistance Performance of Nano-Multilayer Coatings for the Protection of Breathing Gas Cylinders Used in Diving

Seamless gas cylinders for diving exhibit excellent low-temperature impact performance, lightweight characteristics, and good corrosion resistance, making them widely applicable in underwater activities. However, during use, the peeling of paint or corrosion on the surface of these cylinders poses a significant threat to their safety. In this study, environmentally friendly arc ion plating technology was used to deposit TiBN, CrAlN, and nano-multilayer coatings of CrAlN/TiBN. The surface morphology, tribological properties, and corrosion resistance of these coatings were investigated. The results indicated that both CrAlN and CrAlN/TiBN coatings possess fewer droplets, pinholes, and pits, and the cross-section of the CrAlN/TiBN coating exhibits a denser structure. The preferred orientation for TiBN was identified as TiB2 (101), while that for CrAlN was Cr(Al)N (200), with the preferred orientation for CrAlN/TiBN being TiB2 (101). The friction measurements revealed that the lowest coefficient was observed in the CrAlN/TiBN coating (0.489), followed by CrAlN (0.491) and then TiBN (0.642). Electrochemical tests conducted in artificial seawater demonstrated that the self-corrosion potential was highest for the CrAlN/TiBN coating, followed by CrAlN and lastly TiBN. The developed TiBN-based nano-multilayer coatings hold substantial application value in protecting seamless gas cylinders used in diving.

Quantitative characterization on influence of surface particles on corrosion behavior of multiarc ion plated CrAlN coatings

Surface particles on multiarc ion plated coatings are common defects, and their influence on the service performance of coatings is rarely defined. The CrAlN coatings were deposited on the tungsten steel (YG8) substrates using multiarc ion plating. The effects of the substrate bias voltages and nitrogen flow rates on the quantity of the surface particles were investigated, and the influence of the surface particles on the corrosion resistance of the coatings is quantitatively characterized. The morphology of surface particles was characterized using a scanning electron microscope. The quantity of the surface particles was counted by image software. The corrosion resistance of the coatings was evaluated through an electrochemical workstation. The results show that the quantity of surface particles decreased with the increase in the substrate bias voltage and nitrogen flow rate. The corrosion resistance of the coatings showed a positive correlation with the quantity of the surface particles, and it decreased dramatically when the quantity of the surface particles exceeded 111/10 000 μm2. The corrosion mechanism of the coatings was attributed to the defect-induced pitting corrosion.

Evaluation of wear resistance of CrN, CrAlN, and TiAlN coatings deposited by multi-arc ion plating on spinning die of Cr12MoV

Abstract This study successfully deposited CrN, CrAlN, and TiAlN coatings on the surface of Cr12MoV substrate using multi-arc ion plating (MAIP). The influence of phase composition and surface morphology on the hardness, adhesion strength, friction performance, and wear mechanisms of these coatings was investigated, with a comparative analysis of their wear resistance. Nanoindentation results revealed that the hardness (H) of CrN, CrAlN, and TiAlN coatings increased by 70.37%, 74.97%, and 75.64%, respectively, compared to the substrate. The hardness (H) and elastic modulus (E) were found to be positively correlated. CrAlN demonstrated superior resistance to deformation, reflected in its higher H/E and H 3 /E 2 radios compared to the CrN and TiAlN. Adhesion tests showed that CrAlN had the strongest adhesion strength to the substrate, with an adhesion force of 81.55 N, representing a 14.78% and 8.46% improvement over CrN and TiAlN, respectively. Friction and wear tests identified CrAlN as having the lowest friction coefficient (0.389), attributed to its high hardness and strong adhesion. The wear mechanisms of CrAlN observed were primarily mild abrasive wear, oxidative wear, and adhesive wear. In comparison, CrN and TiAlN coatings exhibited higher friction coefficients of 0.424 and 0.391, respectively, due to their lower hardness and adhesion, which led to more severe oxidative and abrasive wear. Additionally, the TiAlN coating showed signs of brittle failure in wear scars, likely due to the formation of Al2O3 oxides during wear.

Modeling of cracking behavior of CrAlN coatings on silicon during micro- and nanoindentation

The deformation and failure behavior of any coating governs the performance of the resulting coating system. In the present work, we numerically and experimentally examine the fundamental deformation mechanisms of CrAlN coating on Si substrate, particularly its cracking behavior under indentation processes. For this purpose, CrAlN coatings deposited on monocrystalline Si substrates by pulsed DC magnetron sputtering were subject to indentation procedures with different depths. Subsequent characterization of top surface and cross-sectional morphologies demonstrates a strong dependence of coating profile and microstructures on the initial surface condition of the substrate. Specifically, uniform CrAlN coatings with a thickness of 1.1 μm and densified columnar microstructures were prepared on a polished Si substrate. Berkovich nanoindentation test with an indentation depth of 530 nm derives the mechanical properties of the prepared CrAlN coating. The corresponding finite element simulation reveals the propensity of cracking initiation accompanied by the stress concentration at three edge corners of the dent. Subsequent microindentation test with an indentation depth of 1.09 μm demonstrates the coexistence of plastic deformation and brittle fracture of CrAlN coating. In particular, surface radial cracks within CrAlN coating are experimentally and theoretically observed, and the cracking processes are analyzed in detail by finite element simulations.

Corrosion resistance and conductivity of CrN, CrAlN, and CrTiN coatings applied to bipolar plates for proton exchange membrane fuel cells

In order to improve the corrosion resistance and conductivity of 316L stainless steel bipolar plates used for proton exchange membrane fuel cells, three Cr-containing nitride coatings were deposited on 316L stainless steel by multiarc ion plating. First, the microstructure, composition, and contact angle of the three coatings were systematically investigated. Then, electrochemical impedance spectroscopy, potentiodynamic polarization, potentiostatic polarization (PSP), and interfacial contact resistance (ICR) of the three coatings were also fully examined. The results revealed that CrN coating has the highest contact angle of 98.26°, indicating its superior hydrophobicity. Additionally, CrN coating performed the best corrosion resistance with the highest corrosion potential of 0.31 V, the lowest corrosion current density of 2.28 × 10−7 A cm−2, and the largest resistance. Furthermore, CrN coating showed the lowest current density during PSP tests and the smallest ICR value after corrosion. The superior corrosion resistance of CrN coating is mainly attributed to its decreased pore density caused by vacancylike defects and its uniform structure. This article provided evidence for the potential application of CrN coating to bipolar plates.

Electrochemical corrosion and tribocorrosion behavior of CrN and CrAlN coatings in artificial seawater

AbstractThis study investigated the corrosion and tribocorrosion behavior of CrN and CrAlN coatings deposited on steel through direct current magnetron sputtering. Additionally, the effects of Al addition on the microstructure, corrosion inhibition, and tribocorrosion behavior of CrN coatings were evaluated. Compared with the CrN coating, the CrAlN coating exhibited a denser columnar crystal structure and a higher hardness of 23.8 GPa. The CrAlN coating reacted with water to form Al2O3 and Cr2O3 films, which enhanced its corrosion resistance. Moreover, the addition of Al enhanced the wear resistance of the CrN coating and reduced the material loss due to corrosion, wear, and their synergistic effects. The CrAlN coating exhibited a low corrosion current density of 1.14 × 10−8 A/cm2, indicating a 92% reduction compared with the CrN coating. Furthermore, under either open circuit potential or anodic accelerated tribocorrosion conditions, the CrAlN coating featured significantly lower total material loss and synergistic material loss than the CrN coating, demonstrating higher corrosion and tribocorrosion protection.

Study on Microstructure, Mechanical Properties, Tribological Properties and Service Performance of CrAlN and CrAlBN Coatings Deposited on Powder Metallurgy High-Speed Steel (PM-HSS) and Shaper Cutter by Arc Ion Plating Technique

CrAlN and CrAlBN coatings were prepared on the surface of high-speed steel and shaper cutter by physical vapor deposition (PVD) technique using arc ion source. In the process of coating preparation, the adhesive layers were deposited by low bias voltage (−40 V) and the working layers are deposited by high bias voltage (−130 V). The effects of the addition of B element on the microstructure, hardness, elastic modulus and wear resistance of CrAlBN coating were studied. The results show that B element and its compounds exist in amorphous form in the coating, resulting in lattice distortion of the coating, increase of coating hardness to 37.1 GPa, and decrease of elastic modulus to 406.2 GPa. The addition of B element increases the uniformity of the columnar structure distribution and decreases the width of the columnar structure and grain size. The resistance to elastic deformation and plastic deformation of CrAlBN coating is improved, the wear resistance is improved. The performance of CrAlN and CrAlBN coatings on shaper cutter was studied. It was found that the main failure mode of shaper cutters is boundary wear and the wear mechanism of coatings had changed obviously. CrAlBN coating is mainly due to fatigue induced failure, accompanied by some diffusion wear. The addition of B element makes the CrAlBN coating have excellent resistance to oxidative wear, abrasive wear and diffusion wear during cutting. The results show that the addition of B element can improve the microstructure and mechanical properties of CrAlN coating, and the preparation of CrAlBN coating on the surface of the shaper cutter can significantly improve the service life of the coated shaper cutter, which has significance for the development of the shaper cutter industry.

Achieving ultrastrong-tough CrAlN coatings with low friction coefficient by Y incorporating

Despite having otherwise outstanding hardness and oxidation resistance, CrAlN-based hard coatings are limited by poor fracture toughness and high friction. Although incorporating alloying elements such as C and Magnéli phase-forming elements like V, W, Nb, etc, offer one opportunity for additional toughness and low friction, it requires significant and undesirable compromises to high-temperature performance. Therefore, this work explores an alternative, facile route to achieve ultrastrong-tough CrAlN-based coatings with low friction by incorporating Y. The results indicated that the doped Y elements primarily dissolved in the CrAlN crystalline lattice. Increasing the Y content from 0 to 2 at.% resulted in a change in preferred orientation from (111) to (200), accompanied by a crystal transition from typical columnar grains to unusual equiaxed grains. Notably, when the Y content was about 1.2 at.%, the coating exhibited the maximum toughness of 9.65 MPa·m1/2, almost 2 times larger than that of pure CrAlN coating. Additionally, this coating demonstrated a high hardness of 36.7 GPa and a reduced coefficient of friction (COF) of 0.32. These improvements were attributed to the synergistic contribution of the ultrastrong-tough capability and the formation of Cr2O3 lubricating phases, facilitated by the small amount of Y doping.

Enhanced corrosion resistance and mechanical properties of CrAlON coatings under alternating hydrostatic pressure

CrAlN coatings and CrAlON coatings with varying oxygen content were prepared on the surface of TC4 using multi-arc ion plating. Oxygen introduction resulted in the formation of a (CrAl)(ON) solid solution, leading to finer coating grains and enhanced corrosion resistance. Following a 240-hour immersion in an alternating hydrostatic pressure (AHP) environment, the coatings retained strong adhesion to the substrate. Moreover, they displayed varied improvements in surface hardness and corrosion resistance. The CrAlN coating's improved performance is due to the formation of a surface passivation film, while the high‑oxygen CrAlON coating's enhancement is primarily attributed to filling surface defects with corrosion products under static water pressure.

Effect of process parameters on the growth and wear resistance of CrAlN coating on silicon nitride surface

PurposePreparing CrAlN coatings on the surface of silicon nitride bearings can improve their service life in oil-free lubrication. This paper aims to match the optimal process parameters for preparing CrAlN coatings on silicon nitride surfaces, and reveal the microscopic mechanism of process parameter influence on coating wear resistance.Design/methodology/approachThis study used molecular dynamics to analyze how process parameters affected the nucleation density, micromorphology, densification and internal stress of CrAlN coatings. An orthogonal test method was used to examine how deposition time, substrate temperature, nitrogen-argon flow rate and sputtering power impacted the wear resistance of CrAlN coatings under dry friction conditions.FindingsNucleation density, micromorphology, densification and internal stress have a significant influence on the surface morphology and wear resistance of CrAlN coatings. The process parameters for better wear resistance of the CrAlN coatings were at a deposition time of 120 min, a substrate temperature of 573 K, a nitrogen-argon flow rate of 1:1 and a sputtering power of 160 W.Originality/valueSimulation analysis and experimental results of this paper can provide data to assist in setting process parameters for applying CrAlN coatings to silicon nitride bearings.

Mechanical and Tribological Properties of CrCN, CrAlN, and CrAlCN Coatings Deposited on Tungsten Carbide Substrates by High-Power Impulse Magnetron Sputtering Technology

Mechanical and Tribological Properties of CrCN, CrAlN, and CrAlCN Coatings Deposited on Tungsten Carbide Substrates by High-Power Impulse Magnetron Sputtering Technology

Substrate dependent cracking behavior of CrAlN coatings

SummaryThe present study investigated the effect of substrate deformation behavior on crack resistance of CrAlN coatings under quasi‐static and cyclic loads using nanoindentation. (Cr47Al53)N coatings were deposited on cemented carbide WC‐Co and high‐speed steel HS652C substrates through physical vapor deposition (PVD) und characterized. In order to study the coating cracking behavior, the coated substrates were subjected to quasi‐static nanoindentations with indentation force Fmax = 1 N, Fmax = 1.5 N and Fmax = 2 N. Moreover, the crack resistance under cyclic loading with frequency f = 0.16 Hz was analyzed at F = 1 N and F = 1.5 N after n = 900 cycles. A conical diamond indenter was used for the tests. At the end, the indentation imprints were analyzed by scanning electron microscopy (SEM). The substrate dependency was apparent in cracking behavior of the coating. Albeit the lower indentation depth compared to the variant with HS6‐5‐2C substrate, the CrAlN coating on WC‐Co substrate showed surface cracks under quasi‐static and cyclic loading. These cracks on the coated surface were absent in the variant with HS6‐5‐2C substrate. This could be related to higher resistance of cemented carbide substrates against plastic deformation, prompting earlier crack initiation in CrAlN coating for effective energy dissipation during indentation.

Investigation of the Influence of Triboactive CrAlMoN Coating on the Joint Wear of Grease-Lubricated Roller Chains

Physical vapor deposition (PVD) coatings are vital for enhancing wear resistance. However this technology faces challenges when coating inaccessible surfaces due to its line-of-sight characteristic. A potential remedy is utilizing triboactive CrAlMoN coatings. These form a tribofilm in the contact zone when applied to one contact partner along with a suitable lubricant. This tribofilm can subsequently safeguard inaccessible yet tribologically stressed surfaces. One of the main applications for this method is roller chain drives, whose longevity depends on the joint wear and the resulting chain elongation. Large-scale pin coatings have proven effective in curbing wear and prolonging chain life. However, the inaccessibility of bushes complicates standard PVD coating procedures. Triboactive coatings offer the possibility of forming transfer layers on the bushes, thereby enhancing friction reduction and wear protection. Experimental material studies for chain drives can be cost-intensive due to complexity and numerous components. This article demonstrates that CrAlN and CrAlMoN coatings in combination with greases with the additives phosphorus and sulfur can reduce friction and wear in chain joints. Furthermore, it is shown that a reasonable selection of tribometer testing can significantly reduce costs. Comparing the results of tests on a pin-on-disk tribometer and component tests show that model tests cannot completely replace component tests. But the combination offers an efficient way to optimize test matrices. Triboactive coatings like CrAlMoN hold promise for addressing the challenge of inaccessible surfaces. Reasonable tribometer test selection can help mitigate the costs of experimental studies, making these coatings a more practical solution.

Influence of annealing temperature on microstructural, mechanical and chemical properties of CrAlN coatings

CrAlN coatings were deposited using RF magnetron sputtering on to SS 304 substrates. To check the thermal stability of the coatings, they were annealed in air from 500 °C to 900 °C. Different characterizations such as structural, microstructural, mechanical and chemical studies were carried out. It was observed that the coatings retained their properties till 700 °C and then at 800 °C, the coatings showed degradation in some of the properties. Field Emission Scanning Electron Microscopy (FESEM) suggested no change in the microstructure till 800 °C and then, there was formation of cracks at the annealing temperature of 900 °C. From Raman analysis, the formation of some detectable oxides was confirmed for coatings annealed at 800 °C and 900 °C. At 800 °C, the coating showed a little decrease in the mechanical parameters which further degraded to a hardness value of 13.50 ± 2.31 GPa as the annealing temperature increased to 900 °C. After carrying out these measurements, the chemical stability was also studied by doing corrosion test and Electrochemical Impedance Spectroscopy (EIS) of the coatings in 3.5% NaCl solution and the coatings were found to show outstanding corrosion resistance even after being annealed at a temperature as high as 800 °C which slightly decreased as the temperature increased further. Post corrosion mechanical properties of the annealed coatings were also observed.

Studies on Protective Coatings for Molding Tools Applied in a Precision Glass Molding Process for a High Abbe Number Glass S-FPM3

Precision glass molding (PGM) is an efficient process used for manufacturing high-precision micro lenses with aspheric surfaces, which are key components in high-resolution systems, such as endoscopes. In PGM, production costs are significantly influenced by the lifetimes of elaborately manufactured molding tools. Protective coatings are applied to the molding tools to withstand severe cyclic thermochemical and thermomechanical loads in the PGM process and, in this way, extend the life of the molding tools. This research focuses on a new method which combines metallographic analysis and finite element method (FEM) simulation to study the interaction of three protective coatings—diamond-like carbon (DLC), PtIr and CrAlN—each in contact with the high Abbe number glass material S-FPM3 in a precision glass molding process. Molding tools are analyzed metallographically using light microscopy, white light interferometry, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The results show that the DLC coating improved process durability more than the PtIr and CrAlN coatings, in which the phenomenon of coating delamination and glass adhesion can be observed. To identify potential explanations for the metrological results, FEM is applied to inspect the stress state and stress distribution in the molding tools during the molding process.

Thermal shock resistance of Cr/CrN/Cr/CrAlN multilayer anti-erosion coating

In this work, a 12 μm Cr/CrN/Cr/CrAlN erosion-resistant multilayer coating was prepared by arc ion plating. According to the application conditions of high-temperature changing environment, the high-temperature thermal shock performance and erosion resistance of the coating were studied. The results show that the Cr/CrN/Cr/CrAlN coatings show no change after thermal shock up to 700 °C. After thermal shock at 900 °C, the surface shows discolouration and wrinkling, and the nitride phase in the coatings disappears and Cr2O3 and α-Al2O3 phases appear. The hardness of the coating after thermal shock is reduced from 3658.57 Hv to 1930.96 Hv, and the adhesion strength is reduced from HF1 to HF4. The erosion rates of the coatings after thermal shock at room temperature, 300 °C, 500 °C and 700 °C do not vary significantly, and are within 1 mg/g at 30° and 90°. The coating is completely unprotective when the thermal shock temperature reaches 900 °C, reaching 2.731 mg/g at 30° and 4.832 mg/g at 90°. It shows that the coating has an anti-erosion protection effect within 700 °C, but the coating has completely failed after a thermal shock at 900 °C and has no protective effect.

Effect of Ag addition on the oxidation behavior of CrAlN coating at elevated temperatures

The effect of oxidation temperature and amount of Ag addition on CrAlN coating was investigated in this study. No Ag and Ag-based CrAlN coatings were deposited on a substrate using a physical vapor deposition (PVD) technique. The coatings then were isothermally heated at 800 °C and 900 °C for the 2 hr. Interestingly it is found that even with a small difference in temperature (100 °C), CrAlNAg coating shows different nature of oxidation, mass gain curve, coating microstructure and surface morphology.Surface morphology revels the Ag clusters formation on the top associated with the high temperature heating. While cross-section morphology gives information about Ag distribution and oxides layer formation. Mass gain curve and EDS (Energy-dispersive X-ray spectroscopy) results revealed that the oxidation resistant behavior of the CrAlN coating was degrade with increasing Ag content and/or increasing oxidation temperature. Overall, the results suggest that the temperature has a significant effect on the microstructure and properties of Ag-based coatings, and optimizing the deposition temperature can improve the performance of these coatings in various applications.

NANOHARDNESS AND MODULE OF ELASTICITY OF CR-BASED NITRIDE COATINGS DEPOSITED AT TEMPERATURES BELOW 200°C

Sets of Cr-based hard coatings were prepared via reactive closed field unbalanced magnetron sputtering (CFUBMS). Substrate temperature was kept in range of 150 to 200ºC during deposition. Nanohardness (H) andeffective modulus of elasticity (E*) of the CrN, CrAlN, CrTiN and CrTiAlN coatings were examined using depth-sensing indentationmethod. The results from the combined examination of the research ratios showed that the triple and quaternary hard coatings have superior mechanical properties and they strongly depend on the deposition conditions

Relationship of the structural, mechanical, and tribological behaviors among TiCN, BCN, and CrAlN coatings in the fatigue life of AISI 1045 steel for automotive industry

Relationship of the structural, mechanical, and tribological behaviors among TiCN, BCN, and CrAlN coatings in the fatigue life of AISI 1045 steel for automotive industry

Application of Multiple Nitrogen-based Coatings for Cemented Carbide Tools: A Review

As the main-stream of the machining coating, nitrogen-based coatings have irreplaceable advantages, such as high hardness, high strength, and good oxidation resistance recently. This paper introduces common multiple nitrogen-based coatings which including TiAlN, CrAlN, TiAlSiN, CrAlSiN and CrTiAlN coatings for cemented carbide tools. The microstructure and property of coating is depended on its chemical composition. Generally, compounds of different structures are formed between the various elements of the coating, and these have different forms of existence and properties: titanium and chromium exist in nitrides (face-centered cubic structure), aluminium solubilizes in TiN/CrN, and amorphous Si3N4 can make difference in fine grain strengthening. The Al2O3 and SiO2 can improve oxidation resistance.