Comparison on the structural, mechanical and tribological properties of TiAlN coatings deposited by HiPIMS and Cathodic Arc Evaporation

https://doi.org/10.1016/j.surfcoat.2021.127529Get rights and content

Highlights

  • Comparison between the Ti50Al50N thin film coating produced by HiPIMS and CAE.

  • Influence of HiPIMS process parameters on the micro-mechanical properties of the Ti50Al50N coatings.

  • Hardness, E-modulus and Wear resistance of Ti50Al50N-HiPIMS by comparison with CAE.

  • High performances of Ti50Al50N coatings synthesized by HiPIMS during a ball-on-disc test by comparison with CAE coatings.

Abstract

TiAlN single layer coatings deposited by High-Power Impulse Magnetron Sputtering (HiPIMS) on carbide and Si-wafers substrates were performed. They were characterized in order to study the effects of different process parameters on the film stoichiometry, microstructure and morphology and finally their mechanical and tribological properties were investigated. For comparison, the properties of the same composition Ti50Al50N coatings produced by Cathodic Arc Evaporation (CAE) were also studied. Only the most influential process parameters, which are the effects of duty cycle, pressure, power and bias for the HiPIMS process are here discussed. High-resolution TEM images were used to investigate the microstructure of CAE and HiPIMS coatings and the observations indicate that both processes produced high density Ti50Al50N coatings with a fine fibrous structure, and a similar grain size. XRD analyses showed that TiAlN coatings deposited by CAE and by HiPIMS have a single-phase cubic structure with respectively the (200) and (111) reflection peaks as a preferred orientation. Furthermore, the residual stresses determined by XRD for the HiPIMS coated samples show that it can be possible to tune them from tensile (+500 MPa) to high compressive stresses (−4000 MPa) by adjusting the process parameters. Independently of their intrinsic stress level, the HiPIMS coatings show similar hardness and the values obtained are in the same range of CAE coatings (30–35 GPa) with same composition and thickness. However, during ball-on-disc tests in dry condition using a steel ball against the coated carbide substrate, the behaviour of similar Ti50Al50N as deposited coatings produced by these two processes was different. Lower friction coefficients (−30%) but, higher abrasion kinetic of the steel ball as counterpart during pin-on-disk test (+50%) were recorded for the Ti50Al50N HiPIMS coatings. In conclusion, it is proposed that, for HiPIMS coatings with high compressive stresses (<−5000 MPa), having also low surface roughness and (111) main texture orientation, high tribological properties can be achieved.

Introduction

The mechanical and friction properties of binary titanium nitride (TiN) coatings obtained by Physical Vapor Deposition (PVD) can cover a large spectrum of cutting performance needs. However, due to this material's low oxidation resistance – the oxidation onset point is around 600 °C – more efforts were needed to make this type of material more resistant to oxidation. By adding other elements such as aluminium (Al) to the films, these ternary coatings can improve their thermal behaviour and consequently, their in-service life [1,2]. The ternary titanium-aluminium-nitride (TiAlN) coatings have been studied due to their outstanding mechanical and physical properties, such as thermal stability, wear properties and corrosion resistance [3,4]. The focus for this type of coatings on commercial cutting tools is now to improve its sustainability in the machining process under a completely dry environment [5].

Cathodic Arc Evaporation (CAE) deposition of TiAlN coatings on cemented carbides is currently one of the main used technique in the industrial applications compared to direct current Magnetron Sputtering (dcMS) and High-Power Impulse Magnetron Sputtering (HiPIMS) techniques. It has the advantage of having high deposition rates with a large ratio of ionized vapor [6]. However, the main disadvantage of CAE is the negative effect of microscopic droplets on the coating topography [7,8].

Since Mozgrin et al. published the first HiPIMS coating deposition in 1993 [9], HiPIMS has gained more and more substantial interest amongst industrialists as a future technique for coating applications. Over the last years, hard nitride coatings were deposited by HiPIMS and proposed to the market as an alternative to similar CAE coatings. On the other side, academic works have also reported interests for the mechanical properties of titanium nitride-based coatings synthesized by HiPIMS. It is difficult here to give an extensive view of the works already published, but some of them can be given as illustration. Firstly, it is claimed that this process leads to smoother surface coatings and it offers a better control of thin film growth morphology compared to CAE [6,10,11]. Alami et al. reported the enhanced ionization sputtering and thus an increased coating density of TiN HiPIMS coatings [12]. The improvement of the quality and the uniformity of TiAlN coatings deposited by HiPIMS were proposed by Shimizu et al. [13]. Hardness enhancements using HiPIMS were reported by Guillaumot et al. for AlN coatings [14]. However, as far as the authors know, a direct comparison between the same titanium nitride coatings processed by HiPIMS on the one hand and CAE on the other hand, and deposited on the same substrates and at the same substrate temperature was not really considered. Therefore, in this present work, we report the effect of different Ti50Al50N HiPIMS deposition conditions on the mechanical properties of the coating like the intrinsic stress, the hardness and the wear resistance in comparison to CAE coatings. The comparison covers the effect of pressure and bias, as well as the duty cycle on the time-dependent discharge characteristics and on the film chemistry and microstructure.

Section snippets

Experimental and characterization

A set of Ti50Al50N single layer coatings were deposited on mirror-polished silicon wafers (Si) with a crystal orientation of 100 ± 0.5° and on polished cemented tungsten carbide (WC-Co) plane discs, produced from a mixed powder of (WC-9%Co) and other carbide elements like (Ti, Ta, Nb) C with 14.55 g/cm3 density. Before depositing the coatings, both substrates were cleaned in an ultrasonic bath using ethanol for 5 min. The coatings were carried out by dcMS or HiPIMS technique inside a PVD coater

Results and discussion

Table 1 summarizes the main deposition conditions for the two processes and data for the TiAlN coatings with the composition determined by EDX and the structural information by XRD. In both types of coatings, the nitrogen is close to stoichiometry (±2 at.%), while the Al content is slightly lower by CAE coatings than by HiPIMS. This latter feature could be the effect of the droplet formation at the coating surface generally observed in Arc discharge as these droplets are generally reported to

Conclusions

Same hard Ti50Al50N coating deposited with the same composition and the same thickness by an CAE and a HiPIMS process, completed in few cases by also, Ti50Al50N coating deposited by dcMS have been performed. All these coatings, independently of the deposition process, have the same morphology with a very dense columnar structure, which is not affected by the substrate, silicon wafer or WC-Co and by the nature of the adhesive interlayer. However, there is a clear structural difference between

Abbreviations

    HiPIMS

    High-Power Impulse Magnetron Sputtering

    dcMS

    direct-current Magnetron Sputtering

    CAE

    cathodic Arc evaporation

    FE-SEM

    Field-Emission Scanning Electron Microscope

    EDS

    Energy Dispersive X-ray Spectrometer

    TC

    Texture coefficient

    SAED

    Selected Area Electron Diffraction patterns

    HRTEM

    High Resolution Transmission Electron Microscopy

    FFT

    Fast Fourier Transformer

    Ra

    Roughness average

CRediT authorship contribution statement

M-R. Alhafian: Conceptualization, methodology, investigation, design of experiments, writing – original draft, editing, and submission.

J-B. Chemin: Supervision, PVD set up, process parameterization, and review.

Y. Fleming: XRD measurements validation, methodology, and review.

L. Bourgeois: Scientific discussion, mechanical properties validation, and review.

M. Penoy: Fiber texture and pole figures measurements, and investigation.

R. Useldinger: Scientific discussion

F. Soldera: Supervision,

Declaration of competing interest

Mohamed Riyad AlHAFIAN reports financial support was provided by Luxembourg National Research Fund (FNR).

Acknowledgements

The authors thank Dr. N. Valle (LIST) and Dr. J. Ghanbaja (Institute Jean Lamour, France) for their participations to the characterizations of our samples and for valuable discussions. The financial support from the Luxembourg National Research Fund (FNR) under the CORE PPP project funding for innovation and industry partnerships (C-PPP17/MS/11622578) is gratefully acknowledged, as well as the European Doctoral Program in Advanced Materials Science and Engineering (DocMASE) for the training of

References (50)

  • A. Guillaumot et al.

    Reactive deposition of Al-N coatings in Ar/N2 atmospheres using pulsed-DC or high power impulse magnetron sputtering discharges

    Vacuum.

    (2010)
  • N.J.M. Carvalho et al.

    Stress analysis and microstructure of PVD monolayer TiN and multilayer TiN/(Ti,Al)N coatings

    Thin Solid Films

    (2003)
  • S. Sveen et al.

    Scratch adhesion characteristics of PVD TiAlN deposited on high speed steel, cemented carbide and PCBN substrates

    Wear.

    (2013)
  • M. Tkadletz et al.

    The effect of droplets in arc evaporated TiAlTaN hard coatings on the wear behavior

    Surf. Coatings Technol.

    (2014)
  • C.V. Falub et al.

    Interdependence between stress and texture in arc evaporated Ti-Al-N thin films

    Surf. Coatings Technol.

    (2007)
  • K.D. Bouzakis et al.

    Cutting with coated tools: coating technologies, characterization methods and performance optimization

    CIRP Ann. Manuf. Technol.

    (2012)
  • K.D. Bouzakis et al.

    Application in milling of coated tools with rounded cutting edges after the film deposition

    CIRP Ann. Manuf. Technol.

    (2009)
  • G. Greczynski et al.

    A review of metal-ion-flux-controlled growth of metastable TiAlN by HIPIMS/DCMS co-sputtering

    Surf. Coatings Technol.

    (2014)
  • G. Greczynski et al.

    Selection of metal ion irradiation for controlling Ti 1-xAl xN alloy growth via hybrid HIPIMS/magnetron co-sputtering

    Vacuum.

    (2012)
  • A. Leyland et al.

    On the significance of the H/E ratio in wear control: a nanocomposite coating approach to optimised tribological behaviour

    Wear.

    (2000)
  • K. Sarakinos et al.

    High power pulsed magnetron sputtering: a review on scientific and engineering state of the art

    Surf. Coatings Technol.

    (2010)
  • H. Elmkhah et al.

    Correlation between the duty cycle and the surface characteristics for the nanostructured titanium aluminum nitride coating deposited by pulsed-DC PACVD technique

    J. Alloys Compd.

    (2017)
  • L. Zauner et al.

    Reactive HiPIMS deposition of Ti-Al-N: influence of the deposition parameters on the cubic to hexagonal phase transition

    Surf. Coatings Technol.

    (2020)
  • R. Machunze et al.

    Stress and texture in HIPIMS TiN thin films

    Thin Solid Films

    (2009)
  • H. Elmkhah et al.

    Surface characteristics for the Ti[formula presented]Al[formula presented]N coatings deposited by high power impulse magnetron sputtering technique at the different bias voltages

    J. Alloys Compd.

    (2016)
  • Cited by (27)

    View all citing articles on Scopus
    View full text