Structural Development and Interfacial Engineering of Hard Coatings by HIPIMS (High Power Impulse Magnetron Sputtering)

Jörg Paulitsch

Research output: ThesisDoctoral Thesis

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Abstract

The material surface and its performance are of great interest, especially in automotive applications, since any contact between moving parts, e.g. piston and cylinder, takes place via their surfaces. Consequently, surface modifications are needed to optimize materials for special applications. One possibility to increase the surface properties and thereby the lifetime of components is to deposit thin films by e.g., physical vapour deposition (PVD) techniques. Conventional direct current magnetron sputtering (DCMS) is a well established PVD technique to deposit protective coatings. Nevertheless the drawback of DCMS is its low ionization rate of the sputtered species, which is a requirement for depositing dense hard coatings. High power impulse magnetron sputtering (HIPIMS) is a pulsed PVD technique, allowing for high electrical power densities by decreasing the duty cycles (on-time divided by the cycle time) of the pulse. The high power densities result in increased ionization of the sputtered species and thereby the deposition of dense hard coatings with increased mechanical and tribological properties. The main drawback of the HIPIMS process is its low deposition rate when compared to DCMS. The aim of this work was to investigate the HIPIMS technique for industrial applications especially when depositing complex shaped or round-symmetric samples where multi-fold substrate rotations during deposition are required. Monolithic CrN and TiN coatings, as well as their multilayer arrangements, are investigated in detail using HIPIMS and DCMS in an industrial scale deposition unit, as these coatings are already well investigated for DCMS. This allows elucidating the influence of HIPIMS, with respect to DCMS, on the mechanical and tribological properties as well as the resulting microstructure of the coatings, when using static and/or multiple substrate rotation during deposition. Furthermore, to increase the deposition rate of the HIPIMS process, a hybrid HIPIMS/DCMS deposition technique was investigated. The results demonstrate the advantage of this new simultaneous combination of HIPIMS with DCMS, as thereby multilayered CrN/CrN coatings with increased mechanical and tribological properties combined with an increased deposition rate can be obtained. The preparation of multilayered CrN/TiN hard coatings with the hybrid HIPIMS/DCMS process allows for friction coefficients of around 0.05, comparable to those of diamond like carbon (DLC), and therefore enables new application areas of low friction film deposition.
Translated title of the contributionStrukturentwicklung und Interfaceengineering von Hartstoffschichten mittels HIPIMS (High Power Impulse Magnetron Sputtering)
Original languageEnglish
QualificationDr.mont.
Supervisors/Advisors
  • Dehm, Gerhard, Assessor B (internal)
  • Mayrhofer, Paul Heinz, Assessor A (internal)
Publication statusPublished - 2010

Bibliographical note

embargoed until 13-01-2015

Keywords

  • HIPIMS
  • DCMS
  • low friction
  • CrN
  • TiN

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