Cathodic Arc Evaporation Technique Research Articles

The influence of corrosive medium on the selected tribological properties of ZrSi-based nitride and oxynitride deposited on 316L stainless steel

Targeting to restore the function of load-bearing joints which are subjected to high levels of friction and wear during the normal activity, the aim of the current study was to assess the extent of the role played by the corrosive environment on the underlaying tribological mechanism. In this study we deposited by reactive cathodic arc evaporation technique ∼ 1 μm thick, stoichiometric ZrSi-based nitrides and oxynitrides coatings, either as monolayer or double-layer structure on 316L steel substrates. Tribological tests were conducted in dry and two commonly used corrosive environments: Ringer and 0.9 % NaCl solutions. We demonstrate that the ZrSiN and ZrSi(N,O) coatings improved the wear performance of 316L stainless steel in biological environments, reaching even ∼ 94 % improvement as compared with the bare substrate for the ZrSi(N,O) coating.

The effect of substrate bias voltage on the mechanical and electrochemical corrosion properties of multilayered CrN/CrAlN coatings produced by cathodic arc evaporation

AbstractThe multilayered CrN/CrAlN film was deposited on the SS420 substrate by cathodic arc evaporation technique. The effect of substrate bias voltage was investigated on the microstructure, surface morphology, and mechanical and electrochemical corrosion properties of the deposited film. The deposited CrN/CrAlN coatings were characterized by X‐ray diffraction and field emission scanning electron microscope techniques. Mechanical properties, corrosion resistance, and surface morphology of the coated samples were studied by nano‐indentation, polarization test, electrochemical impedance spectroscopy, and atomic force microscopy, respectively. Adhesive and dense nanostructure CrN and CrAlN phases were successfully deposited on the substrate. The refinement of the coating crystallite was observed from 31.2 to 24.3 nm by increasing the substrate bias voltage, this improved the mechanical properties of the coating. The number of macroparticles, pinholes and porosities, and the surface roughness of coatings significantly decreased by increasing the substrate bias voltage. The CrN/CrAlN coating reduced the corrosion current density in contrast to the SS420 substrate. Better corrosion resistance was obtained for the coating deposited at 150 V of bias voltage due to lower defects in the film structure.

Whether macro-droplets generate or develop in depositing hard coatings by cathodic arc evaporation technique

The deposition of hard coatings of different materials on low-performance tools, intricate parts, and low-cost or less favorable materials is a topic of great worth. This study discusses the deposition of titanium nitride coatings on high-speed steel discs by employing the cathodic arc evaporation technique. Before the deposition of titanium nitride coating, a titanium layer is deposited on the substrate to enhance adhesion between the substrate and coating. In one experiment, the titanium nitride coating deposits without the titanium interlayer. When there is no deposition of the titanium interlayer at the start of the process, the developing different-sized droplets or particles are lower. When there is a deposition of the titanium interlayer first for 8 and 16 min, there are also droplets. In the published literature, the investigated hard coatings suggest generating different-sized droplets. However, such concepts cause hurdles in coating technology advances and reducing droplets. The study has a pronounced effect on scientific and industrial research in different areas. The study aims to investigate whether the droplets develop or they generate. From the application of some well-known characterization techniques, the discussed results confirm the development of droplets in the deposited hard coating rather than the generating.

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.

Wear behaviour of AlCN/AlC and FeCrN coatings developed on alloy steel

ABSTRACT The fretting wear and adhesive wear resistance of Al and Fe-based thin solid films deposited onto MDN121 steel are studied. Plasma-assisted cathodic arc evaporation technique (P-CAE) is used to develop AlCN/AlC and FeCrN monolayer coatings. The coatings and wear tracks are characterised by FESEM-EDS, nanoindentation, Raman spectroscopy, optical profiler, and confocal microscope. The results reveal that during fretting and adhesive wear, tracks are investigated using confocal microscopy and electron microscopy. When fretting wear occurs, the Coefficient of Friction (COF) dramatically decreases for AlCN/AlC thin solid films by 48.65% and for FeCrN thin solid films by 62.16% when compared to the substrate. FeCrN coating exhibits lower volumetric wear loss than AlCN/AlC coating. The wear surface morphology of both monolayer coverings against galling failure in the substrate exposes the abrasive form of the fretting wear process. Thin solid films of AlCN/AlC and FeCrN experience a COF reduction during adhesive wear of 40.89% and 56.22%, respectively, in comparison to the substrate. The FeCrN monolayer coating exhibits low friction and wear rate compared to AlCN/AlC monolayer coating.

Improvement of the Wear Resistance of Circular Saws Used in the First Transformation of Wood through the Utilization of Variable Engineered Micro-Geometry Performed on PVD-Coated WC-Co Tips

Reduced performance of circular saws due to premature chipping of their teeth has been a critical issue in woodcutting industry for many years. This research examined the impact of surface coating and variable engineered micro-geometry of the cutting edges of carbide teeth (tips) on the wear resistance of circular saws used in primary wood processing. CrN/CrCN/DLC, CrN/AlTiN, CrN/CrCN, and CrCN/TiSiCN were deposited on tungsten carbide-cobalt (WC-Co) substrates using the cathodic arc evaporation technique. The CrN/CrCN coating proved to be the one with highest wear resistance and adhesion among those studied. No sign of delamination was observed around the indentation of the CrN/CrCN coating after the adhesion test. Furthermore, no abrasion, delamination or crack was observed on the surface of the CrN/CrCN coating after the three-body abrasion wear test. The results of the dry-sliding wear test revealed that CrN/CrCN coating significantly decreased the wear rate of WC-Co substrates by 74%, 66% and 77% at sliding speeds of 50, 100 and 250 mm/s, respectively. Afterwards, a CrC/CrCN coating was deposited on the teeth of conventional circular saws. Next, the cutting edges of teeth were modified through variable engineered micro-geometry. Tests were conducted at a sawmill with three series of saws: 1-coated and edge-modified, 2-coated and conventional edge geometry, and 3-uncoated and edge-modified. Wood processing was performed during two shifts of 480 min each. The width of the wear land was the criterion used as the wear index. The results of industrial tests showed that saws with edge-modified teeth had significantly less chipping and no breakage at their corners compared to the saw without edge modification (conventional saw). After 480 min of sawing, the wear rate of the coated saw with edge modification decreased by 46% and 16%, compared to the coated saw without edge modification and the uncoated saw with edge-modified teeth, respectively. Those values reached 73 % and 41%, respectively, after 960 min of sawing. The study shows that by optimizing the surface chemistry and the geometry of the cutting edge of WC-Co tips, tool life can be significantly increased therefore reducing downtime due to saw replacement and resharpening, thus significantly increasing productivity in the first transformation of wood.

Tribological properties of in-situ PVD TiAlN, TiSiN, and TiAlN/TiSiN coatings under ambient air and vacuum environment

It is known that the interest in manufacturing in a vacuum environment has increased in recent years. Thus, the wear behavior of mechanical tools under vacuum conditions has critical importance. However, adhesion and cold-welding problems between tool and working piece in vacuum conditions lead to poor wear properties and severe coefficient of friction values. Surface treatment methods such as physical vapor deposition coatings can eliminate these undesirable consequences, especially transition metal nitrides. In this study, TiAlN, TiSiN, and TiAlN/TiSiN films were coated on AISI H13 tool steels employing the cathodic arc evaporation technique. Whether the coatings grown to the substrate surface have a positive contribution to the wear performance of the substrate in the ambient air and vacuum environment was answered. Scanning electron microscope, energy dispersive spectrometer, and X-ray diffractometer analyses were used to attain structural properties. The hardness was measured using a nano-hardness tester, and the adhesion properties were determined by a scratch test. The wear behavior of the substrate and coating samples are determined under 2 N constant normal load and using WC-6%Co counter bodies under ambient air and vacuum conditions. The hardness of samples improved owing to surface coatings, and the highest nano-hardness value was determined from the TiSiN coatings as 39.42 GPa, which is ∼700% greater than the substrate. It has been observed that coated samples have superior wear performance in both wear conditions. Besides, it is determined that those tested under a vacuum condition showed superior wear resistance than the samples tested under ambient air. While TiSiN film exhibits the highest wear resistance in ambient air, the TiAlN/TiSiN layer is the best in a vacuum environment. Owing to the deposited coatings, the seizure mechanism between the friction surfaces, which is frequently encountered in the vacuum environment, is prevented, and a fascinating improvement in terms of friction coefficient is achieved.

The Effect of Al and Ti Transition Metals on the Wear Resistance of Ceramic Based CrN Coatings; Investigation under Ambient Air and Vacuum Conditions

In the present study, CrN, CrAlN and CrAlTiN coatings were deposited using the cathodic arc evaporation technique. The structural investigations of these CrN based coatings were performed by scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy, X-ray diffractometer. The hardness and adhesion strength values of coatings were determined via Vickers type microhardness tester and progressive load scratch tester, respectively. The wear performance of samples was established at ambient air and vacuum condition. All coatings grew in the “T zone” growth model and had a dense and columnar structure. The XRD patterns presented predominantly (220), (110), and (111) reflections. It was demonstrated that the quaternary coating had a higher texture parameter as 0.68, which was related to the highest thickness and hardness. Also, CrAlTiN coatings with the smallest mean crystallite size of ∼87 nm showed the best hardness, and this ensured relatively high scratch resistance. CrN and CrAlTiN coatings improved wear performance under ambient air condition but were not striking as under vacuum condition. The quaternary coating had a superior performance in the vacuum condition, but due to the high sensitivity of Ti to oxygen, it fell behind the CrN coating under ambient air condition.

Adhesion and machining performance of PVD AlCrN coatings with an ion beam/laser textured substrate

The insufficient adhesive strength of Physical Vapor Deposition (PVD) coatings is still the key issue that needs to be solved urgently for high-efficiency and high-quality difficult-to-machine materials cutting processing. Currently, laser micromachining is extensively utilized to fabricate micro-textures on the substrate to enhance coatings adhesion. However, laser ablation will cause irregular protrusions inside and on the edges of the textures, which could influence the quality of deposited coatings. Therefore, micro-textures were fabricated on the substrate by an ion beam (IBE)/laser machining method, and the influence of IBE/laser textures on the adhesive strength of PVD coatings is revealed. Firstly, a micro-pits array was prepared on WC/Co substrates with different machining parameters, such as laser repetition frequency and ion beam etching time. The micro-topography and mechanical properties of the substrates with different pretreatments were studied. Then, cathode arc-evaporation technique was utilized to deposit AlCrN film on the IBE/laser textured substrates. The scratch test and dry machining experiments of AISI 316 L stainless steel were performed to evaluate the adhesive strength and machining performance of the coated samples with various pretreated substrates. The results demonstrate that laser texturing and ion beam etching both enhanced the coatings adhesion. Therefore, the critical load of the coatings deposited on the IBE/laser textured substrates with 25 kHz laser repetition frequency and 150 min etching time (F N, C2 = 3.39 N) exhibited the highest value, which was 19.4% higher than that of the conventional AlCrN samples (F N, C2 = 2.84 N). Moreover, the cutting forces F X , F Y , F Z and the friction coefficient of IBE/laser textured coated tool were decreased by 18.7%, 20.6%, 10.2% and 16.7% compared with that of conventional coated tool at the high cutting speed of 200 m/min. Finally, the possible mechanisms of IBE/laser texturing pretreatment on enhancing PVD coatings adhesion were discussed. • A micro-pits array is fabricated by an ion beam (IBE)/laser machining method. • Effect of ion beam (IBE)/laser textures on adhesion of PVD coatings is studied. • Mechanism of IBE/laser texturing to improve coatings adhesion is revealed.

Assessment of Ion Release for Ni-Cr Dental Alloy with Monolithic and Multilayer Coatings in Different pH Level

We successfully formed nanostructured TiN, CrN, and multilayered TiN/CrN coatings on the Ni-Cr alloy using a cathodic arc evaporation (CAE) technique. Coatings were exposed to artificial saliva solutions with two pH of 5 and 8 to investigate their ion release. We measured the surface roughness of produced coatings using atomic force microscope (AFM). CrN coatings exhibited smoother surface, while TiN and TiN/CrN coatings showed surfaces with greater roughness. X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS) were used to investigate the microstructure of coated and uncoated Ni-Cr samples. We found that the greatest ion release was apparent for uncoated samples in artificial saliva solutions with two pH of 5 and 8. The least ion release was found for CrN coatings once pH was 8 indicating that the coating performance was affected by pH variation and CrN coatings offered the strongest hindrance against ion release.

Improving fretting corrosion resistance of CoCrMo alloy with TiSiN and ZrN coatings for orthopedic applications

Total hip replacement is the most effective treatment for late stage osteoarthritis. However, adverse local tissue reactions (ALTRs) have been observed in patients with modular total hip implants. Although the detailed mechanisms of ALTRs are still unknown, fretting corrosion and the associated metal ion release from the CoCrMo femoral head at the modular junction has been reported to be a major factor. The purpose of this study is to increase the fretting corrosion resistance of the CoCrMo alloy and the associated metal ion release by applying hard coatings to the surface. Cathodic arc evaporation technique (arc-PVD) was used to deposit TiSiN and ZrN hard coatings on CoCrMo substrates. The morphology, chemical composition, crystal structures and residual stress of the coatings were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffractometry. Hardness, elastic modulus, and adhesion of the coatings were measured by nano-indentation, nano-scratch test, and the Rockwell C test. Fretting corrosion resistance tests of coated and uncoated CoCrMo discs against Ti6Al4V spheres were conducted on a four-station fretting testing machine in simulated body fluid at 1Hz for 1 million cycles. Post-fretting samples were analyzed for morphological changes, volume loss and metal ion release. Our analyses showed better surface finish and lower residual stress for ZrN coating, but higher hardness and better scratch resistance for TiSiN coating. Fretting results demonstrated substantial improvement in fretting corrosion resistance of CoCrMo with both coatings. ZrN and TiSiN decreased fretting volume loss by more than 10 times and 1000 times, respectively. Both coatings showed close to 90% decrease of Co ion release during fretting corrosion tests. Our results suggest that hard coating deposition on CoCrMo alloy can significantly improve its fretting corrosion resistance and could thus potentially alleviate ALTRs in metal hip implants.

Microstructure and tribomechanical properties of multilayer TiZrN/TiSiN composite coatings with nanoscale architecture by cathodic-arc evaporation

Multilayer TiZrN/TiSiN coatings were deposited on steel substrate by the cathodic-arc evaporation technique. The TiZr (75:25 at. %) and TiSi (95:5 at. %) alloy cathodes served as evaporation sources. Scanning electron microscopy with energy-dispersive spectroscopy, secondary ion mass-spectrometry, X-ray diffraction and X-ray photoelectron spectroscopy were employed to investigate the microstructure, elemental composition, phase state and bonding structure of the deposited coatings. Nanoindentation and ball-on-disk tribology tests were used to measure the mechanical and tribological features of the coatings, such as hardness, elastic modulus, toughness, friction coefficient and wear rate. The results show that all multilayers were fcc structures with a strong preferred orientation along (111) plane. The coherent growth of the multilayers contributed to the formation of the fine-grained structure with crystallites of 9.2–11.6 nm size and a low level of residual stresses of− (3.5–5.3) GPa. All multilayer coatings exhibited high hardness up to 38.2 ± 1.15 GPa and elastic modulus up to 430 ± 12.9 GPa, indicating higher resistance against plastic deformation compared to TiZrN and TiSiN films. The result of ball-on-disk wear tests showed that the multilayer sample with the best structural features (modulation period of 20.4 nm, 0.86 at. % of Si, the crystallite size of 9.2 nm and residual stress of− 3.5 GPa) demonstrated the lowest friction coefficient of 0.844 and better wear rate of 3.32·10–5 mm3/N m.

Investigation of physical and electrical properties of TiN-coated SS316L as bipolar plate of proton exchange membrane fuel cells

ABSTRACT In this research, TiN films were deposited on the SS316L substrate by cathodic arc evaporation technique, to use as bipolar plates in proton exchange membrane fuel cells. The effect of substrate surface roughness and film thickness on the interfacial contact resistance and corrosion properties of the TiN films was investigated. Characterization of deposited films was performed by XRD, XRF, ICR, contact angle, and FESEM equipped with energy-dispersive spectroscopy. Electrochemical and surface properties of deposited films were studied by potentiodynamic scanning, electrochemical impedance spectroscopy, and AFM analysis. It is observed that the surface roughness of the substrate, before deposition, has a significant impact on the final properties of TiN coating, especially when the coating thickness is less than 1.2 µm. All of the coated samples showed better corrosion resistance in comparison to the substrate, and the corrosion current density decreased from 1.65 to 0.16 μA cm–2 when coating thickness increased from 0.6 to 1.5 µm.

Controllable preparation of micro-textures on WC/Co substrate surface by an integrated laser-dry etching process for improving PVD coatings adhesion

The micro-texture fabricated on the substrate surface of coatings is an established method for enhancing the Physical Vapor Deposition (PVD) coatings adhesion. Currently, laser micromachining is widely used to prepare the micro/nano-texture. Nevertheless, it has a problem of low processing accuracy, such as irregular texture edges and irregular protrusions inside the textures. Here, we propose an ion beam etching (IBE)-assisted laser machining approach to fabricate micro-texture, and the effect of IBE/laser textures on the PVD coatings adhesion is revealed for the first time. The profile evolution mechanism of the micro-textures on the cemented carbide during etching process was investigated. By IBE-assisted laser machining, a ring-shaped microholes array with high precision and controllability was fabricated on the cemented carbide substrate surface. Then, the textured substrates were coated with TiAlN materials using cathode arc-evaporation technique. The scratch tests and dry wear tests on the coatings with the textured substrates were carried out, demonstrating that the IBE/laser textured coatings exhibited higher adhesive strength compared to that of the untextured and laser textured ones. Thus, the IBE-assisted laser machining shows a great potential in the preparation of high precision micro-textures for enhancing PVD coatings adhesion.

A study on the corrosion resistance of ZrN/CrN multilayer nanostructured coating applied on AISI 304 stainless steel using Arc-PVD method in 3.5 wt% NaCl solution

In this research, a ZrN/CrN multilayer nanostructured coating was applied on AISI 304 stainless steel substrate using physical vapor deposition (PVD) in type of cathodic arc evaporation (CAE). The microstructure evaluation of the specimens were analyzed by x-ray diffraction and scanning electron microscopy. Impedance spectroscopy tests were utilized to evaluate the corrosion behavior of ZrN/CrN multilayer nanostructured coating and the substrate in 3.5 wt% NaCl solution. Applying CAE technique, ZrN/CrN multilayer nanostructured coating having high density and adhesion was successfully made. The corrosion results revealed that ZrN/CrN multilayer nanostructured coatings had an exceptionally high polarization resistance compared to AISI 304 stainless steel substrate. Moreover, the corrosion results showed the desired corrosion behavior in the ZrN/CrN multilayer nanostructured coating towards the AISI 304 substrate within the 3.5 wt% NaCl solution due to the presence of distinct layer resulting in a barrier against penetration of the corrosive solution. Scanning electron microscopy micrographs revealed that the surface of the ZrN/CrN multilayer coating is free of pits or any serious damage.

Comparison of the wear and corrosion behavior between CrN and AlCrN coatings deposited by Arc-PVD method

In this investigation, we studied deposition of chromium nitride (CrN) and aluminum chromium nitride (AlCrN) coatings on the steel substrate by using cathodic arc evaporation technique (Arc-PVD). Therefore, the wear and corrosion behavior of the CrN and AlCrN coatings were compared. Applying cathodic arc evaporation at 200 °C for 90 min led to a coating with approximately 2 micrometers thickness. In order to compare the properties of CrN and AlCrN coatings, all of the Arc-PVD methods coating parameters were kept at a constant value within the deposition of coating having the duty cycle of 50 percent, bias voltage of −100 V, and the target current of 100 A. For characterizing the crystal structure and microstructure of the coatings, x-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) were utilized. In order to evaluate the coatings adhesion and the wear behavior, Rockwell-C indenter and the pin-on-disk test were used, respectively. Moreover, a potentiodynamic polarization device was used in 3.5% NaCl solution for studying the corrosion behavior of the coatings. The results revealed that CrN coating has the lower friction coefficient but AlCrN coating showed better wear resistance. Also, CrN coating had a better corrosion resistance than AlCrN on account of the uniform surface morphology and the absence of void which protects the substrate from the corrosive medium.

Evaluation of adhesion and erosion/corrosion resistance of nano-composite and nano-multilayer thin films in molten aluminum alloy

Die casting as a well-known manufacturing method to produce high precision aluminum parts, encounters die failure. The most important wear and failure mode of die casting process is washout damage on working die surfaces attributed to erosion, corrosion, and soldering. Washout caused by a thermo-chemical interaction between aggressive aluminum melt and die steel on the surface. The influence of TiAlN–Si3N4 nanocomposite and TiAlN/TiN nano-multilayer thin film coatings on washout resistance of H-13 tool steel was evaluated in A384 aluminum alloy melt. Thin films were applied by physical vapor deposition using cathodic arc evaporation technique onto pre-nitrided pin-shape samples at 350 °C. X-ray analysis was employed to assess films constitutive phases. Scanning electron microscopy (SEM) investigation and atomic force microscopy approach were employed to indicate surface morphology and roughness of nano-structural coatings. An accelerated immersion test was conducted to compare washout resistance of coated samples by immersion them in aluminum alloy melt for periods of 30, 60, 90, and 120 min at 680 °C. Furthermore, specially developed release test was done to measure wettability and adhesion tendency of samples. SEM investigation of corroded and eroded surface showed some pitting effect on coatings and tribo‐chemical interaction inside the pits between aluminum melt and substrate. Nano-structural coatings not only prevented intermetallic phase formation at the surface but also reduced the erosion/corrosion rate which is known as cause for the washout.

Erosion performance, corrosion characteristics and hydrophobicity of nanolayered and multilayered metal nitride coatings

Nanolayered CrTiN and CrAlTiN and multilayered CrAlTiN-CrN and CrAlTiN-AlTiN coatings were deposited on 17-4PH stainless steel substrate by cathodic arc evaporation technique. All the coatings, nanolayered CrAlTiN and multilayered CrAlTiN-AlTiN coatings in particular, demonstrated higher resistance to solid particle erosion at both low and high impingement angles, when compared to bare 17-4PH substrate and monolithic CrN coating. The mass erosion rates of the CrAlTiN coating were less than 1/3 and 1/7 of the erosion rates of the CrN coating at 30° and 90°, respectively. The enhanced erosion performance was attributed to the increased hardness of the coatings. Potentiodynamic polarization tests in 3.5% NaCl aqueous solution indicated that these coatings had higher corrosion potentials, higher pitting potentials and much wider passive ranges with comparable or lower current densities, when compared to bare 17-4PH. Water contact angle measurements revealed hydrophobic characteristics of these coatings after being exposed to ambient air.

Fabrication of coated tool with femtosecond laser pretreatment and its cutting performance in dry machining SLM-produced stainless steel

Selective Laser Melting (SLM) technique applied to the stainless steel has been developing rapidly in the biomedical and aerospace industries. However, a post-machining is still needed to efficiently improve the surface finish and dimensional precision of the SLM-produced stainless steel parts. Dry machining (machining without the using of cutting fluid) is attracting interest around the world, which can reach green manufacturing without water pollution, residue on the swarf, and danger to health. In this work, to achieve the green finishing machining of SLM-produced AISI 316 L stainless steel, the hard coated tools with a nanotextured substrate were designed, and the key preparation methods of this developed tools were presented. First, a periodic nano-ripple structure (nanotexture) was induced by femtosecond laser scanning on the WC/Co substrate tool with different processing parameters, then TiAlN film was deposited on the nanotextured substrate surface using the cathode arc-evaporation technique without employing any interlayer. The surface micro-topography and mechanical property of the nanotextured TiAlN coated surface were studied. Machining tests without cutting fluid were performed on the SLM-produced stainless steel using the developed tool, and the cutting tool without laser pretreatment was also employed for the comparison. The obtained results demonstrate that, the TiAlN coatings adhesiveness is significantly enhanced by the femtosecond laser-induced periodic structure on the WC/Co substrate, and the critical load of the TiAlN coatings is increased from 57 to 73 N. The improved machining performances of nanotextured tools in drying cutting SLM 316 L stainless steel are achieved, resulting in a decrease of 10–20% in cutting forces, a decrease of 10–15% in cutting temperature and a high surface quality of the machined workpieces at the high cutting speed. The possible mechanisms for the effects of femtosecond laser pretreatment are discussed.

Tribological behaviour of monolayer and multilayer Ti-based thin solid films deposited on alloy steel

The fretting wear and adhesive wear resistance of Ti-based thin solid films deposited on MDN121 steel substrate are evaluated. Plasma-assisted cathodic arc evaporation technique is used to develop the TiC–C monolayer coating and Ti/TiN/TiCN/TiN/TiCN multilayer coatings used in the study. FESEM-EDS, nanoindentation, Raman spectroscopy, optical profiler, and confocal microscope are used to characterise the coatings and wear tracks. Diamond-like carbon is observed in the microstructure of both the coatings. During the fretting analysis, the coefficient of friction (COF) is reduced by 68.49% in the case of the TiC–C monolayer coating and 42.46% in the Ti multilayer coatings as compared to the substrate. The volumetric wear loss of the TiC–C monolayer coating is lower than the multilayer coating. The wear surface morphology reveals the abrasive form of the fretting wear mechanism in both the monolayer and multilayer coatings whereas the galling failure in the substrate. During adhesive wear, the COF is reduced by 71.73% in the monolayer coating and 59.33% in the multilayer coatings compared to the substrate. The monolayer coating exhibits low friction and low wear rate as compared to the multilayer coating.