Titanium Aluminum Nitride Coatings Research Articles

Wear Behavior of TiAlN/DLC Coating on Tools in Milling Copper–Beryllium Alloy AMPCOLOY® 83

In recent years, the exponential growth of the machining industry and its needs has driven the development of new manufacturing technologies, more advanced cutting tool types, and new types of coatings to extend tool lifespan. New coating solutions have been studied and implemented for machining tools, which provide a low friction coefficient and lubrication, thus increasing tool lifespan. Following this line of reasoning, it is relevant to develop scientific work aimed at studying the behavior of cutting tools coated with thin films that promote low friction and high lubrication, as is the case with DLC (diamond-like carbon) coatings. These coatings promote good resistance to oxidation and allow high machining speeds, properties also exhibited by TiAlN (titanium aluminum nitride) coatings. In fact, there is a gap in the literature studying the performance of cemented carbide tools provided with multilayered coatings in milling operations of Cu–Be alloys, commonly used in inserts of plastic injection molds. This study’s objective was to investigate the effect of a multilayer coating (TiAlN/DLC) on end-milling tools to analyze their cutting performance when milling a Cu–Be alloy known commercially as AMPCOLOY®83. The quality of the machined surface was evaluated, and the wear of the cutting tool was studied. A comparative analysis of milling parameters with respect to their effect on the condition of the surface after machining and the resulting wear on the tools, using coated and uncoated tools and different machining parameters, allowed us to verify a better quality of the machined surface and wear quantified in approximately half when used coated tools.

Machinability Performance of Single Coated and Multicoated Carbide Tools During Turning Ti6Al4V Alloy

AbstractThis paper presents the machinability performance of uncoated, single-coated, and multicoated carbide tools during turning of Grade 5 (Ti6Al4V) Titanium alloy, which is challenging to machine due to its distinctive material properties. Coated tools with single-coated Titanium Aluminium Nitride (TiAlN) and multi-coated layer of Titanium Aluminium Nitride with Aluminium Chromium Nitride (TiAlN + AlCrN) coated inserts were utilized to assess surface roughness (Ra), tool wear rate (R), and chip morphologies under various cutting conditions using dry machining. Analysis of the used tools revealed that coated tools exhibited improved tool life and surface quality compared to uncoated tools across all cutting conditions. Multi-coated tools of TiAlN + AlCrN demonstrated a tool life increase of up to 15% compared to uncoated and single-coated tools, with surface roughness improvements ranging from 30 to 45% depending on cutting speed. Chip morphology analysis indicated an increase in the chip reduction coefficient with higher cutting speeds for all tool types. Coated tools exhibited the lowest chip-reduction coefficient due to the presence of TiAlN and AlCrN coatings, which control the tool chip contact length. Conversely, uncoated chip morphology resulted in larger chip thickness values compared to coated tools, particularly at cutting speeds above 100 m/min, attributed to poor heat dissipation and chemical reactions at the tool chip interface. Energy dispersive X-ray scanning electron microscopy (SEM/EDXS) analysis of worn uncoated inserts revealed a higher tendency towards Titanium adhesion compared to coated tools. The proposed multi-layer coatings of (TiAlN + AlCrN) used for dry machining proved highly beneficial for achieving economic machining objectives and may reduce the need for lubrication when processing Ti6Al4V alloys.

Surface Enhancement of Titanium-Based Coatings on Commercial Hard Steel Cutting Tools

This study investigates the mechanical properties, surface integrity, and chemical configuration of PVD-coated high-speed steel (HSS) cutting tools, with a particular focus on titanium nitride (TiN) and titanium aluminium nitride (TiAlN) coatings. A range of characterisation methodologies were employed to examine the impact of pre-coating surface conditions on the resulting coatings. This impact includes the effects of gas bubble production and unequal distribution of elements, which are two unwanted occurrences. Notwithstanding these difficulties, coatings applied on surfaces that were highly polished exhibited more consistency in their mechanical and elemental characteristics, with a thickness ranging from 2 to 4 µm. The study of mechanical characteristics confirms a significant increase in hardness, from an initial value of roughly 1000 HV0.5 for untreated tools to 1300 HV0.5 for tools with physical vapour deposition (PVD) coatings. Although PVD coatings produced on an industrial scale might not exceed the quality of coatings manufactured in a laboratory, they do offer substantial enhancements in terms of hardness. This study highlights the significant importance of thorough surface preparation in achieving enhanced coating performance, hence contributing to the efforts to prolong the lifespan of tools and enhance their performance even under demanding operational circumstances.

Erosion-Corrosion Behavior and Mechanism of TiAlN Coating Under Different Flow Conditions in Simulated Seawater

Erosion-corrosion behavior of high-speed steel (HSS) and titanium aluminum nitride (TiAlN) coating were investigated under different flow conditions in simulated seawater. On the front side (facing toward the direction of water flow), there was a negligible failure of the TiAlN coating, but clear marks of erosion-corrosion on the HSS. Notwithstanding, unexpected failure features were identified on the back side (back against the direction of water flow) on both specimens because the high-velocity water flow was localized at the edge and the center was high in turbulence. For the HSS, there was dominant corrosion in the center and dominant erosion at the edge. For the TiAlN/HSS coating, the dense and layered structure retards the propagation of surface cracks as the major failure into the bulk and instead promotes layer-by-layer spallation. Additionally, visible “flow marks” were observed on both specimens and can be explained by the flow-accelerated-corrosion.

Change with the Reactive Deposition Mode in Crystallographic and Mechanical Properties of Titanium Aluminum Nitride Coatings Obtained Via Grid-Assisted Magnetron Sputtering

Change with the Reactive Deposition Mode in Crystallographic and Mechanical Properties of Titanium Aluminum Nitride Coatings Obtained Via Grid-Assisted Magnetron Sputtering

The Effect of TiN, TiAlN, TiCN Thin Films Obtained by Reactive Magnetron Sputtering Method on the Wear Behavior of Ti6Al4V Alloy: A Comparative Study

Titanium-based alloys have gained worldwide application over the past century. However, their low wear resistance remains an unresolved challenge for the Ti6Al4V alloy, which has significant industrial use. Therefore, it is an integral part in material selection and surface treatment in friction-wear applications. Tribological properties are not only material parameters but also system parameters where test conditions are essential. Hardness, roughness and contact conditions of coatings, which are especially important in surface treatments, affect wear modes. In this study, titanium nitride, titanium aluminum nitride and titanium carbon nitride coatings were obtained by unbalanced reactive magnetron sputtering to improve the weak tribological properties of Ti6Al4V alloy. The wear behavior was studied at room temperature in dry conditions. Wear tests were conducted under different loads and different sliding rates, which were followed by comparative analyses of their wear resistances. While the coated samples showed higher wear resistance than the uncoated Ti6Al4V alloy, the lowest wear track width was observed in TiN coating. Depending on the surface properties of the coatings, adhesion, abrasion and oxidation wear mechanisms were observed. It was concluded that a TiN coating could be a material of choice for applications where triple abrasive wear is dominant.

Development of a durable ice protective coating for use on rotorcraft

Ice protective coatings could revolutionize the aviation industry as they could assist or even replace traditional ice protection systems that increase the vehicle weight and power requirements. A major problem for many potential ice protective coatings is durability. This paper explores whether erosion resistant titanium aluminum nitride coatings (TiAlN) can be made ice protective by reducing both surface roughness and coating defects (such as pin holes or scratches). Cathodic arc physical vapor deposition was used to deposit TiAlN on 304 stainless steel. The coatings were polished post deposition using a vibratory polisher to achieve the highest quality coating to date (surface roughness of 12.6 nm). Aircraft representative impact ice adhesion strength testing was conducted using an instrumented centrifugal adhesion testing rig. The test results demonstrated that TiAlN coatings can be made ice protective. Coatings with a surface roughness of 12.6 nm were found to have an ice adhesion strength of 1.4 psi at −8 °C, with a droplet impact velocity of 60 m/s, icing cloud density of 0.9 g/m3, and a droplet median volumetric diameter of 20 μm. The research conducted not only demonstrated the capability to reduce ice adhesion strength by reducing surface roughness, but also showed that as TiAlN coatings became smoother (surface roughness varying from 1690 nm to 12.6 nm) the dependence of ice adhesion strength on temperature decreased. The result presented demonstrates that aircraft ice adhesion strength is a highly mechanical phenomenon as the ice interacts with the surface morphology.

Coating-thickness-dependent physical properties and cutting temperature for cutting Inconel 718 with TiAlN coated tools

IntroductionCoating-thickness-dependent physical properties can induce different cutting temperatures with physical vapor deposition (PVD) titanium aluminum nitride (TiAlN) ceramic-coated tools. The determination of the optimal TiAlN coating thickness is important to obtain superior coating physical properties and decrease the cutting temperature of Inconel 718 alloy. ObjectivesThe present study investigates the effects of coating thickness on the physical properties of TiAlN coatings and the cutting temperature during the machining of Inconel 718 alloy. The optimal coating thickness is also determined. MethodsFirst, the direct-current-arc method was utilized to deposit PVD Ti0.55Al0.45N coatings with thickness of 1.6 µm, 2 µm, 2.5 µm, and 3 µm, onto a cemented carbide substrate. Second, the coating-thickness-dependent physical properties were characterized and estimated with a radar chart. Third, the effects of coating thickness on coating antifriction were analyzed with the tool-chip friction coefficient when cutting Inconel 718 with PVD TiAlN coated tools. Both the maximum cutting temperature generated in the chip and the cutting temperature of the tool bodies were measured for analyzation of the thermal barrier effect of coating. Finally, the topographies of the deformed chip and tool-chip contact area were obtained and investigated to determine the effects of coating thickness on the cutting temperature. ResultsThe tool-chip friction coefficient and coating thermal barrier effect were affected by the coating thickness. Ti0.55Al0.45N coated tools with moderate coating thickness had fine antifriction effect with Inconel 718. The thermal barrier effect of Ti0.55Al0.45N coating was positively related to the coating thickness. ConclusionsThe optimal TiAlN coating thickness was determined as 2 μm, which resulted in superior physical properties and reduced the cutting temperature of Inconel 718.

Characterization and Performance of TiAlN and TiN Coatings on Plasma-Nitrided AISI 4140 Steel

Abstract Steels can go through a duplex treatment process, consisting of depositing a physical vapor deposition (PVD) coating on plasma-nitrided substrates. The coating layer varies from 1.5 to 5 µm, depending on the application needs. The work's objective is to analyze the performance and evaluate the mechanical characteristics of titanium nitride (TiN) and titanium aluminum nitride (TiAlN) coatings deposited in AISI 4140 with quenched/tempered or plasma-nitrided treatment. Scanning electron microscopy/energy dispersive spectroscopy and X-ray diffraction performed the microstructural and chemical characterization of the duplex-treated samples. The mechanical properties were measured by performing nanohardness tests, allowing the extraction of hardness and elastic modulus out of the load/unload behavior of the samples, and the scratch test according to ASTM C1624-05 (2010), Standard Test Method for Adhesion Strength and Mechanical Failure Modes of Ceramic Coatings by Quantitative Singles Point Scratch Testing (Superseded), coupled with acoustic emission analysis, probed adhesion of the TiN and TiAlN coating on the steel substrates. Also, pin-on-disk tribological tests probed the wear resistance of the duplex-treated samples. It was found that the nitriding process increases the surface hardness and elastic modulus. The TiAlN coating has the highest load capacity with the least amount of wear. The adhesion of the TiAlN coatings is worse than TiN.

Deposition of TiN and TiAlN Thin Films on Stainless Steel Tubes by a Cylindrical Magnetron Sputtering Method

Abstract Titanium nitride (TiN) and titanium aluminum nitride (TiAlN) coatings are very hard materials that are mostly coated on cutting tools to increase the tool life. These coatings have also been successfully applied as a coating material for biomedical applications mainly due to their tribological properties, biocompatibility, and affordable price. In an attempt to develop transition metal nitride coatings on specimens of cylindrical geometry, TiN and TiAlN thin films were deposited successfully on stainless steel tubes using a direct-current cylindrical magnetron cosputtering method. Both types of coatings were uniform in nature and had good adherence to the substrate. TiN and TiAlN thin films were characterized systematically to determine their structure, surface morphology, chemical states, chemical structure, and electrochemical behavior using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and potentiodynamic methods, respectively. The XRD patterns of the TiN and TiAlN coatings indicated (111) preferential orientation. Cross-sectional SEM images revealed a columnar growth of the coatings with an arrow-headed geometry. XPS characterization showed the presence of TiN, Titanium dioxide, titanium oxynitride, aluminum oxide, and aluminum nitride phases. Potentiodynamic polarization tests in 3.5 % sodium chloride solution revealed that the TiAlN coating exhibited superior corrosion resistance compared with the TiN coating. Furthermore, TiAlN coating showed 94 % of average absorption in ultraviolet-visible region using photospectrometry. The cylindrical magnetron sputter deposition technique enables development of uniform protective coatings on tubular geometries, which are frequently employed in solar thermal and nuclear applications.

Detailed study of the electrochemical behavior of low-reflectivity TiAlN coatings

Titanium aluminum nitride (TiAlN) is proposed as a coating to decrease the reflectivity of surgical instrumentation, thereby improving the field of vision of surgeons during procedures, although the corrosion resistance of the material against repeated sterilization processes must be guaranteed. The influence of aluminum (Al) on the microstructural and electrochemical properties of low-reflectivity titanium aluminum nitride coatings deposited by direct-current unbalanced magnetron sputtering was evaluated. The optical properties, chemical phases and composition were determined using the ultraviolet–visible spectroscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction techniques. The microstructures were analyzed by atomic force microscopy, scanning electron microscopy and transmission electron microscopy–selected area electron diffraction. The corrosion resistance was evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization. It was found that an increase in the aluminum content reduced the coating reflectivity by 60%, showing a dense columnar crystalline structure with a grain size of 200–100 nm and roughness of 6.7–4.0 nm and the coexistence of titanium nitride (TiN), aluminum nitride (AlN), titanium aluminum nitride and aluminum oxide (Al2O3) phases. In comparison with AISI 420 steel, the TiAlN-1300W aluminum coating showed a more positive corrosion potential, as well as a current density two orders of magnitude lower, thus guaranteeing corrosion resistance.

A comparative analysis over different properties of TiN, TiAlN and TiAlSiN thin film coatings grown in nitrogen gas atmosphere

Titanium nitride (TiN), Titanium aluminum nitride (TiAlN), and Titanium aluminum silicon nitride (TiAlSiN) coatings were deposited over Silicon (Si) (100) substrates using chemical vapor deposition (CVD) process at a constant temperature under different N2 flow rate. Scanning electron microscopy (SEM) images reveal a smoother TiN coating surface compared to other coatings. Atomic force microscopy (AFM) indicates enhancement of particle size of TiN and TiAlN coatings with higher N2 gas flow rate. However, the particle size of TiAlSiN found to decrease with a higher N2 flow rate. X-ray diffraction (XRD) results confirm the diffraction phases of TiN, TiAlN and TiAlSiN at (111) and (200) crystal planes. The electrochemical test indicates higher corrosion resistance of TiAlSiN coating as compared to other coatings. Nano-indentation results reveal that TiAlSiN possesses higher hardness (H) and Young's modulus (E) as compared to other coatings.

Temperature distribution of cubic boron nitride–coated cutting tools by finite element analysis

Heat generation in cutting process has a great influence on performance and lifetime of cutting tools. Cubic boron nitride (cBN), combination of exceptional thermal conductivity and hardness, is a promising super-hard material as protective coatings on the cutting tools. However, the temperature distributions of micron-thickness coatings on cutting tools are very difficult to be examined by experiment methods. In this paper, finite element method (FEM) simulation was introduced to determine the temperature distribution of cBN/diamond coatings on silicon nitride (Si3N4) cutting tools with various parameters compared with titanium aluminum nitride (TiAlN) coatings. The finite element (FE) model of cBN/diamond–coated Si3N4 tools was built and validated by machining experiments. The effects of cutting speed and tool rake angle on temperature distribution of cBN/diamond–coated tools were investigated compared to TiAlN coatings based on developed model. The results show that the temperature is increased with the increase of cutting speed while decreased with the increase of tool rake angle. The temperature of cBN-coated tools is decreased by approximately 20.4–28.6% than TiAlN-coated tools under identical conditions. Additionally, the preferred cutting speed and rake angle were obtained among employed cutting parameters. The results demonstrated that using advanced cBN coatings can substantially improve the cutting performance of the tools. This work may offer a guideline to explore the temperature distribution of cBN-coated cutting tools in mechanical machining application for machining difficult-to-cut ferrous materials.

Correlation of Microstructural and Mechanical Properties of CVD Deposited TiAlN Coatings

Titanium aluminum nitride (TiAlN) thin films were synthesized with different N2 flow rate on p-type Si (100) substrate and characterized by FESEM, AFM, XRD and nanoindentation to investigate the morphology, structural and mechanical properties. The FESEM images revealed non-uniform grain distribution with a higher degree of pores with the increase in N2 flow rate. The XRD data indicated the presence of AlN, TiAlN, Al2O3 dominant phases at 33.07°, 55.5°, 61.79° and 47.84°, 54.67° diffraction angles attributed to (100), (220) and (400), (112) diffraction plane, respectively. The AFM images revealed the average roughness as 36.9 nm for 30 sccm N2 flow rate. Furthermore, the mechanical properties such as H, E, plasticity index (H/E) and deformation to plastic resistance (H3/E2) of TiAlN thin film were found to be 21 GPa, 400 GPa, 0.094 and 0.318 GPa, respectively, indicating higher resistance to crack with increasing N2 flow rate.

Sand erosion resistance improvement and damage mechanism of TiAlN coating via the bias-graded voltage in FCVA deposition

Titanium aluminum nitride (TiAlN) coatings were deposited on Ti6Al4V alloy substrates using a filtered cathodic vacuum arc (FCVA) deposition method with bias-graded voltage ranging from -50 V to -200 V and constant bias voltage (-50 V, -125 V, and -200 V). The microstructure and mechanical properties of these coatings were investigated and compared. Sand erosion resistance at 30° and 90° was evaluated using sandblasting equipment. The coating deposited at a constant bias voltage of -200 V had the highest average hardness of 32.47 GPa. The bias-graded coating had a similar average hardness (32.08 GPa), but lower internal stress (-2.66 GPa) and considerably higher adhesion strength (44.03 N) than the constant-bias coatings. For both erosion angles (30° and 90°), the erosion rates of the constant-bias coatings increased with increasing bias voltage. In general, the erosion rates of the bias-graded coating (0.014 and 0.013 mg/g at erosion angles of 30° and 90°, respectively) were significantly lower than that of the constant-bias coatings. Bias-graded deposition is an effective method of improving the erosion resistance of coatings. The erosion mechanism of the coatings is coating chipping. The excellent erosion resistance of the bias-graded TiAlN coating is attributed to the high hardness and low internal stress of this coating.

Preparation and Characterization of the Sputtered TiAlN Coatings Using a Ti-Al Alloy Metal Target.

Titanium aluminium nitride (TiAlN) ternary coatings were deposited on glass substrates by means of reactive magnetron sputtering technique, using a Ti-Al alloy metal target (Ti0.5Al0.5). The depositions were performed at various N2 and Ar flux ratios of N₂/(Ar + N₂) ═ 33, 50, 67, 83%. The structure, morphology, chemical composition and mechanical properties were investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDS), and nano indenter (MTS System), respectively. The orientation of coatings depends on the flux ratios of N₂/(Ar + N₂) and substrate temperature. The coatings deposited with N₂/(Ar + N₂) ratios of 33, 50 at.% consists of pyramid-like column grains separated by porous and voids, which can be attributed to cubic-TiN (220) preferred orientation. The coatings deposited with N₂/(Ar + N₂) greater than 67% exhibits the phase of hexagonal-AlN and cubic-TiN. The surface of coatings becomes more compact and smoother with the N₂/(Ar + N₂) ratios increase. The coatings deposited with N₂/(Ar+N₂) ratio of 83% shows the largest hardness of 21.5 GPa, which is attributed to the preferred (200) orientation. However, this hardness increases significantly with increasing substrate temperature. The coatings deposited at more than 100 °C exhibited the (111) and/or (200) orientation. The amounts of grains grown along the (111) and (200) orientations play a significant role on the mechanical performance of TiAlN coatings. Four independent mechanisms, such as TiAlN stoichiometry and lattice parameter, the (111) preferred growth orientation, and the density increases (elimination of void), were found to contribute to the enhancement of TiAlN mechanical performance.

Growth and characterization of TiAlN nanoparticles using low-energy plasma focus device

In this experimental study, a 1.5-kJ plasma focus device of Mather type was employed to grow titanium aluminum nitride (TiAlN) coatings at room temperature on 316 stainless steel sub-layer. The anode of the device was made of Titanium and Aluminium. A mixture of N2 and Ar gases was used as the work gas for TiAlN deposition. TiAlN nanoparticles were formed on stainless steel with 0° of the degree with respect to the anode axis by different shots at 5 cm above the anode. X-ray diffraction results indicated the formation of the TiAlN structure on stainless steel. Scanning electron microscopy images demonstrated the approximately uniform growth of TiAlN nanoparticles on the surface. EDX analysis results showed that an increase in the number of the shots increased the deposition of TiAlN on the sub-layer. According to the atomic force microscopy images, the mean thickness of the surface increased as the shots increased in number. Microhardness test results of the thin layers showed that an increase in the number of the shots increased the hardness of the samples.

Modeling of metastable phase formation for sputtered Ti1-xAlxN thin films

Metastable titanium aluminum nitride coatings are widely applied in cutting and forming applications. Although it is generally accepted that the phase formation of metastable TiAlN is governed by kinetic factors, modeling attempts today are based solely on energetics. In this work, the metastable phase formation of TiAlN is predicted based on one combinatorial magnetron sputtering experiment, the activation energy for surface diffusion, the critical diffusion distance, as well as thermodynamic calculations. The phase formation data obtained from further combinatorial growth experiments varying chemical composition, deposition temperature, and deposition rate are in good agreement with the model. Furthermore, it is demonstrated that a significant extension of the predicted critical solubility range is enabled by taking kinetic factors into account. Explicit consideration of kinetics extends the Al solubility limit to lower values, previously unobtainable by energetics, but accessible experimentally.

Improvement of Tribology in Sheet Metal Forming of High-Strength Steel Sheets by PVD-Coated Dies

During sheet metal formation, the high strength of sheet material leads to high contact stress between the die and blank material, which results in increased die wear. Moreover, the reduction in the use of lubricants because of environmental concerns has led to greater wear of sheet metal–forming dies. It is important to understand the tribological behavior of the blank die contact so that steps can be taken to reduce the die wear to an acceptable level. Die wear reduction is possible by using alternative die materials, modifying die geometry, or by creating a wear-resistant surface on sheet metal–forming dies using Physical Vapor Deposition (PVD) coatings. PVD coatings have a thickness in the micro range and greatly improve the tribological properties of the die material. In this work, three pins made of AISI D2 steel were coated with Titanium Nitride, Titanium Aluminum Nitride (TiAlN), and Aluminum Chromium Nitride using the PVD process. Friction and wear tests were conducted on the pin-on-disk testing machine as per ASTM G99, Standard Test Method for Wear Testing with a Pin-on-Disk Apparatus. The pins had diameters measuring 10 mm and lengths measuring 35 mm. They were heat treated until they reached 55 HRC and ground to a Ra value of 0.1 µm. A 5-mm-radius tip was provided on one end of the pin. D3 steel was used as counter material (disk). The normal load was 30 N, and the sliding speed was 0.3 m/s. The experiments were conducted in dry contact conditions. Based on the results, it was concluded that TiAlN coatings are an excellent choice to modify friction behavior and improve wear resistance of die material.

Comparative evaluation of hot corrosion resistance of nanostructured AlCrN and TiAlN coatings on cobalt-based superalloys

Abstract