Mechanical Properties Of TiN Films Research Articles

Evaluation of the Crystal Structure and Mechanical Properties of Cu Doped TiN Films

In this study, TiN films doped with different copper contents (TiCuN) were prepared by using direct current magnetron sputtering method. The effects of Cu doping on composition, structure, and mechanical properties of TiN films were studied by energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), a Vickers microhardnessmeter, and density functional theory (DFT). The results of experimental and DFT study showed that Cu mainly replaced Ti atoms in TiN to form replacement solid solution doping. When Cu replaced Ti in TiN, a weak Cu-N (bond population varied from 0.06 to 0.11) covalent bond formed; meanwhile, the bonding strength of Ti-N (bond population varied from 0.29 to 0.4) bond adjacent to Cu increased. When Cu content was low, a small number of weak Cu-N bonds were formed, with strengthened Ti-N bond near Cu atom, resulting in an increased hardness of Cu doped TiN films. According to the theory of weak bonds, when the Cu content was increased further, the number of weak Cu-N bonds increased and TiCuN hardness decreased. With an increase in Cu content, it was found the toughness of TiCuN also increased. The results of this study will provide a theoretical and experimental guidance for improving the toughness and deformation resistance of TiN, which has a potential application in the surface modification of medical devices.

Optical, electrical and mechanical properties of TiN thin film obtained from a TiO2 sol-gel coating and rapid thermal nitridation

This study reports the optical, electrical and mechanical properties of TiN films prepared by direct rapid thermal nitridation process from a photo-patternable TiO2 sol-gel layer. The sol-gel approach is compatible to non-planar and large substrates and allows the micro-nanotexturing of crystallized TiN surfaces in a significantly short time, large scale and at a lower cost compared to TiN layer deposition from existing and conventional processes (CVD, PVD, ALD…). In this paper, the optical measurements are carried out by optical spectroscopy in the UV, visible and near-IR region and by ellipsometry. The resistivity and the conductivity are estimated by four-point probe method, while hardness is characterized by nano-indentation experiments. The results indicate that the TiN thin film made by sol-gel method and rapid thermal nitridation are very promising for the manufacturing of optical metasurfaces devices or new plasmonic materials.

Mechanical modification and damage mechanism evolution of TiN films subjected to cyclic nano-impact by adjusting N/Ti ratios

For the purpose of optimizing the anti-impact performance of TiN film, a series of TiN films with different N/Ti ratios were investigated. The phase evolution and mechanical properties of TiN films were explored. In particular, the cyclic nano-impact tests with impact energy ranging from 0.1 μJ to 0.9 μJ were conducted to evaluate the anti-impact performance of TiN films. It was found that the non-stoichiometric phases of TiN0.30, Ti2N and TiN0.61 reduced with increasing N/Ti ratio in TiN films. The hardness of film increased with increasing stoichiometric TiN phase in films, while as an indicator of toughness, the H3/E2 ratio decreased. The anti-impact performance of TiN films displayed a close relationship with both hardness and H3/E2 ratio, in which a high enough hardness was the prerequisite of outstanding impact resistance, and H3/E2 ratio was an important factor affecting the damage mechanism. As the H3/E2 ratio decreased, the damage mechanism of TiN film transformed gradually from plastic fatigue damage to brittle fracture failure. Especially, the TiN film featuring N/Ti ratio of 0.780 (TiN-16) was not only hard enough to resist penetration, but also tough enough to prevent the film from fracturing, thus it exhibited the best comprehensive anti-impact performance.

Relation between work function, microstructural and mechanical properties of TiN-films

ABSTRACTA study of titanium nitride (TiN) films microstructural and mechanical properties at nanoscale using resonance tracking acoustic force atomic microscopy is presented. Also for this study, the work function (Φe) measured for Kelvin Probe Force Microscopy of TiN films deposited by pulsed dc magnetron sputtering is analysed. The films were deposited on Si and glass substrates using a gas mixture ratio Ar–N2 10 and 12% of N2 and power density from 7.4 to 10.8 W cm−2 using the Pulsed DC Magnetron Sputtering. Mechanical properties at nanoscale are measured and a relation between microstructure and nanoscale elastic domains is seen. It was found that the hardness increases when the Φe increases. This directly proportional relationship between hardness and work function, for the first time observed and reported in this contribution, is more accurate and shows a stronger dependence than the relation between hardness and microstructural properties independently.

The Evaluation of the Practical Adhesion Strength of Biocompatible Thin Films by Fuzzy Logic Expert System and International Standards

Abstract This work focuses on describing an evaluation method used in nano- and micro-thin films based on fuzzy logic expert systems. The aim is the elimination of comparison complications with mechanical properties of tin films, practical adhesion being one of the most important characteristic of tin films. The basic method for evaluating the practical adhesion strength is scratch test method, while the issue is that research teams use measurement methods based on the non-uniform measurement conditions of adhesion of biocompatible thin films. The authors tested new evaluation method and procedure based on international standards and fuzzy rule based expert system in order to eliminate the problem of comparison of practical adhesion of the films. The article concentrates on testing and using the fuzzy logic expert system designed based on international standards for evaluating adhesion of thin films in nano and micro dimensions. The materials used for tests of the fuzzy expert system were DLC biocompatible layers and substrate a titanium alloy Ti6Al4V.

Effects of Post Quenching on Mechanical Properties of TiN Film Coated on Steel Substrate

Carbon tool steel substrates were quenched after TiN coating by dc magnetron sputtering, and the effects of substrate post-quenching on the mechanical properties of TiN films were investigated. The residual stress of TiN film was decreased by substrate post-quenching, and the hardness of TiN film also decreased. On the other hand, the adhesive strength determined by the scratch test and the substrate hardness were improved by substrate post-quenching. The improvement in the adhesive strength could be explained by the following three effects of substrate post-quenching: decrease of residual stress, increase in substrate hardness, and the formation of a diffusion layer between the film and the substrate caused by the elevated temperature in substrate post-quenching.

The microstructure and mechanical properties of TiN and TiO 2/TiN duplex films synthesized by plasma immersion ion implantation and deposition on artificial heart valve

Improving the blood compatibility of titanium alloy artificial heart valves by TiO 2/TiN duplex films was studied. In the duplex TiO 2/TiN film, the titanium oxide is for improving blood compatibility and the TiN film is mainly to improve the mechanical property of the films. The mechanical properties of TiN films synthesized by plasma immersion ion implantation and deposition at different bias voltages and substrate temperatures are studied. Its structure is examined using X-ray diffractometry and TEM. The fatigue property of the artificial heart valve modified by TiO 2/TiN duplex film is also investigated. The fatigue property and the wear resistance of the artificial heart valve modified by TiO 2/TiN duplex film are significantly improved compared with bare titanium alloy artificial heart valve. The present investigation shows that TiO 2/TiN duplex film is suitable for applications such as artificial heart valve coating.

The effect of N+-implanted aluminum substrate on the mechanical properties of TiN films

In this work, nitrogen ions were implanted into an aluminum sample prior to magnetron sputtering for deposition of TiN films by self-designed multifunction ion implanter. An 80 nm thick aluminum nitride (AlN) layer is observed by Auger Electron Spectrometer. We examine the effects of AlN layer on the surface mechanical properties of aluminum by nanoindentation. The effects of the AlN layer on the surface mechanical properties are evaluated. The hardness and elastic modulus of the TiN films on the two different substrates (N ion implanted and unimplanted) are almost constant in the near surface region and decrease with increasing indentation depths. A reduced rate of decrease in the hardness and modulus is observed in the TiN/N+-implanted aluminum. From the results obtained by scratch test, the adhesion strength of TiN/N+-implanted aluminum is better than TiN/unimplanted sample.

Effects of Bias Voltage and Discharge Current on Mechanical Properties of TiN Film Deposited by DC Magnetron Sputtering

The effects of bias voltage and discharge current on the mechanical properties of TiN films deposited on carbon steel JIS S45C by reactive do magnetron sputtering are investigated. The residual stress, hardness, toughness and adhesive strength are examined by X-ray diffraction method, nano-indentation test, indentation fracture method and scratch test, respectively. The films are revealed to exhibit high compressive residual stress that increases with the bias voltage and discharge current. The hardness also increases with the bias voltage and discharge current, whereas the adhesive strength decreases and the toughness increases only with increasing bias voltage. The variation of these properties correlates well with the variation in residual stress, regardless of changes in coating conditions. These properties are considered to depend mainly on the residual stress. The width of the X-ray diffraction peak also increased with bias voltage and discharge current, and correlated well with the change in residual stress. It was confirmed that the residual stress was generated by bombardment with high-energy ions during the coating process, and it was concluded that increasing the bias voltage and discharge current had the same effect to enhance the ion bombardment. Based on these findings, the ion bombardment is considered to be the dominant mechanism governing the mechanical properties of TiN films.

Ｄ．Ｃ．マグネトロンスパッタリングにより作製したＴｉＮ薄膜の機械的特性に及ぼすバイアス電圧ならびに放電電流の影響

A study on the effects of bias voltage and discharge current on the mechanical properties of TiN films deposited on carbon steel S45C by reactive D.C. magnetron sputtering was carried out. The residual stress, hardness, toughness and adhesive strength was examined by X-ray method, nano-indentation hardness test, IF method and scratch test, respectively. Quite large compressive residual stress was evaluated and it increased as the bias voltage or discharge current increased. With increasing bias voltage or discharge current, the hardness increased, but the adhesive strength decreased. The toughness increased with increasing bias voltage. The each change of these properties had a good correlation with the change of the residual stress, and was arranged as a data-band regardless of the difference of coating conditions. It was considered that these properties were mainly depended on the residual stress. The half value breadth of X-ray diffraction peak also increased with increasing bias voltage or discharge current, and the change of residual stress showed a good correlation with the change of the half width breadth. It was confirmed the residual stress was produced by the bombardments of high-energy ions toward TiN film in coating process. It was concluded that the increase of bias voltage and the increase of discharge current had a same effect to promote the ion bombardment, and the ion bombardment dominantly influenced the mechanical properties of TiN films.

X-Ray Study of Mechanical Properties of TiN Films Coated on Steel by Ion Beam Mixing(Thin Films)

X-Ray Study of Mechanical Properties of TiN Films Coated on Steel by Ion Beam Mixing(Thin Films)

X-Ray Stress Measurement and Mechanical Properties of TiN Films Coated on Aluminum and Aluminum Alloy Substrates by Arc Ion Plating and Ion Beam Mixing

TiN coatings on cutting tools have greatly succeeded in prolongation of tool lives. In the present study, TiN film deposition was tried on a surface of aluminum and aluminum alloy substrates by means of an arc ion plating (AIP) method and an ion beam mixing (IBM) method. The aim is to develop aluminum-based materials having strong wear resistance. In order to examine the hardness and residual stress of TiN films, the bias the voltage and N2 gas pressure were varied in the AIP treatment and the titanium deposition rate was changed in the IBM treatment. Vickers hardness test revealed high values (HV=1800-2400). The TiN films coated by the AIP and the IBM methods exhibited very high {111} and {110} preferred orientations, respectively. The two-exposure X-ray stress measuring method was used to measure residual stresses in the TiN film. Large compressive residual stresses of -6.3--2.3GPa were developed at lower N2 gas pressures for the AIP method and at higher Ti deposition rates for the IBM method. A wear experiment was also made with a ball-on-disk type wear testing machine. The depth and the width of wear traces on the surface of specimens were greatly reduced when TiN coatings were applied.

Mechanical Properties of TiN Films with the Preferred Orientations by Nano-Indentation Method

TiN films with the (111) and (200) preferred orientations were formed on Si(100) and sapphire(0001) substrates by ion-beam-assisted deposition. The difference in the mechanical properties between the (111) and (200) preferred orientation in TiN thin films was clarified by the nano-indentation technique with the trigonal diamond tip. The experiments revealed significant differences in hardness H and modulus E * irrespective of the substrate materials. The measured values were H=16 GPa, E * =316 GPa for the (200) preferred orientation and H=9 GPa, E * =192 GPa for the (111) preferred orientation. The behavior of the plastic deformation in the TiN films was estimated by the cross-sectional SEM observation and the TEM analysis. These microstructural analyses showed significant difference in cross-sectional views of the plastic deformation and the intergranular fracture mechanism.

Mechanical Properties of TiN Films Deposited on Aluminium Substrates by Arc Ion Plating Method.

TiN film, 3 μm in thickness, was deposited on aluminum (JIS A 1050) and aluminum alloy (JIS A 2017 and JIS A 5052) substrates by an Arc Ion Plating (AIP) method. Bias voltage and N2 gas pressure were changed to examine their role on hardness and residual stress of TiN film. Wear experiment was also conducted using a ball-on-disk type wear apparatus. Vickers hardness tests revealed high value (HV=2 100∼2 400) which depends on both bias voltage and N2 gas pressure. The TiN films exhibited very high {111} preferred orientation. Residual stresses in the TiN film were measured by the two-exposure X-ray stress measuring method as a function of N2 gas pressure. Very high compressive residual stresses, -6.3∼-4.6GPa, were observed. The depth of wear scars on the surface of the processed specimens were greatly shallow.

The effect of nitrogen content on the structure and mechanical properties of TiN films produced by magnetron sputtering

Titanium nitride TiN χ layers with different nitrogen content have been deposited on hard tool steel substrates by unbalanced magnetron sputtering at different nitrogen partial pressures so that the effect of nitrogen content on the structural and mechanical properties of the films could be studied. The film microhardness was found to have a maximum at χ ≈ 0.9. For this value of χ a maximum content of carbon and the highest lattice distortion (especially for the (200) plane) was observed. Chemical bonding between the film components was shown to be the determining factor for the microhardness, as well as intrinsic stress created due to lattice imperfections.

Development and characterization of TiN coatings by ion beam assisted deposition process for improved wear resistance

TiN thin layers have been deposited on mould and die steel STD11 by ion beam assisted deposition (IBAD) process and the wear behaviour of the TiN-coated steel has been evaluated. The synthesis of the TiN film has been performed by irradiation of nitrogen or Xe ions under various nitrogen partial pressures with in situ Ti evaporation at an accelerating voltage range from 25 to 40 keV below 200 °C. TiN coating by Xe irradiation was more effective in enhancing the surface hardness and wear resistance. The formation behaviour and mechanical properties of TiN films synthesized by the IBAD process are discussed with Auger electron spectroscopy, X-ray diffraction and other analysis data. In addition, the performance of TiN coatings on precision moulds and dies in semiconductor manufacturing lines is also discussed.

Effects of nitrogen pressure on arc-evaporated TiN coatings

This article addresses both fundamentals, such as the generation of metal ions and macroparticles (droplets), as well as more practical aspects, e.g. how different process parameters affect microstructure and mechanical properties of TiN films grown on powder metallurgical steel substrates by reactive arc evaporation. A commercially available Multi-Arc equipment has been used to deposit coatings using different nitrogen pressures, substrate-source distances and bias voltages during the growth stage. The microstructural characterisation, regarding droplet number density, surface roughness, changes in the strain and grain size of the deposited coatings, have been performed by scanning and transmission electron microscopy and X-ray diffraction. The influence of the nitrogen pressure on the growth rate, surface roughness and mechanical properties, such as adhesion and scratch resistance, have also been studied by using standard techniques. Only minor changes in the grain size, compressive strain, preferred orientation and adhesion were observed while varying the nitrogen pressure by a factor of ten. In this large process window, general trends such as an increased growth rate and a decreased droplet number density with increasing nitrogen pressure has been established, although these variations are different depending on the substrate-source distances. The increasing nitrogen pressure results in higher deposition rates for the TiN film but in lower ion current densities extracted by the negative substrate bias. This increase in growth rate is discussed in terms of a decreased resputtering effect owing to the observed decrease in ion current density. The major part of the droplets can be concluded to be created during the initial etching/heating stage and their number density decreases linearly with film thickness. An initial discussion regarding the results obtained and a phenomenological explanation of the possible reasons for the dependencies found is proposed.

Effects of preliminary deposition of Ti on mechanical properties of TiN films on iron

Films of Ti, TiN and Ti/TiN were deposited on pure iron substrates by ion plating. Interface analyses were carried out by means of depth-selective conversion electron Mössbauer spectroscopy. The mechanical behaviour of TiN films was investigated by scratch and U-bend tests. Ti interacts with the iron substrate, giving rise to α-Fe(Ti) and α-Ti(Fe) solid solutions, as well as to TiFe 2 and TiFe intermetallic compounds. The solid solutions account for the increased TiN-Fe bonding and the improved mechanical behaviour of TiN.

Mechanical properties of TiN films deposited by changed-pressure r.f. sputtering

Abstract TiN was deposited onto glass, stainless steel and cemented carbide by r.f. magnetron sputtering. The mechanical properties of TiN such as hardness, internal stress and adhesion were assessed by the Vickers microhardness test, the bending method and the modified scratch test. It was found that the operating pressure during sputtering deposition strongly affects these mechanical properties. As the operating pressure is increased beyond 0.6–0.7 Pa, the adhesion of TiN films onto the substrate increases enormously, but the hardness decreases owing to the release of the high compressive stress in the film. Therefore changing the pressure from high to low during deposition could be a good way of optimizing both hardness and adhesion. The effectiveness of this changed-pressure process was experimentally verified by cutting tests using TiN-coated cemented carbide tools. This process will be applicable to any other hard coating materials having high compressive stresses.

Evaluation of mechanical properties of TiN films by ultralow load indentation

The mechanical properties of titanium nitride films of varying composition deposited on stainless steel substrates were studied using an indentation technique with a mechanical properties microprobe which allows measurement of film properties without contribution from the substrate material. A polishing technique was developed that gave consistent indentation measurements on films with initially rough surfaces. The elastic modulus increases linearly with increasing nitrogen content in the N:Ti range of 0.5–1.05, while the hardness of the film depends on other factors. Possible factors contributing to the hardness of the films are discussed.