Abstract
In the last years, quaternary oxynitrides have emerged as a new class of materials due to their tunable properties. Within the present work, a graded TiAl(O)N film was grown by magnetron sputter deposition, using TiAl targets with a Ti/Al atomic ratio of 40/60, constant nitrogen and stepwise increasing oxygen partial pressure over the film thickness. The microstructural evolution of the film was investigated by transmission electron microscopy and synchrotron X-ray nanodiffraction. Complementary, cross-sectional μ-Raman spectroscopy was performed to further validate the phase evolution. The first layer, grown without the addition of oxygen, showed a prevalent wurtzite (w) structure and a subordinate face centered cubic (fcc) phase fraction. The addition of small amounts of oxygen resulted in the stabilization of the fcc-phase and the w-phase vanished. With increasing film thickness and thus, increasing oxygen content, increasing amounts of an additional amorphous phase fraction were observed. In the first layers, tensile in-plain strain was determined, which turns to compressive towards the film surface. Cross-sectional nanonindentation revealed increasing hardness and elastic modulus with increasing oxygen content in the first layers as a result of the w to fcc transition; however, towards the film surface the hardness decreases, which can be related to the increasing amorphous phase fraction.
Original language | English |
---|---|
Pages (from-to) | 155-161 |
Number of pages | 7 |
Journal | Surface and Coatings Technology |
Volume | 359 |
DOIs | |
Publication status | Published - 15 Feb 2019 |
Keywords
- Cross-sectional nanoindentation
- Graded film
- Sputtering
- Synchrotron X-ray nanodiffraction
- TEM
- TiAlON
ASJC Scopus subject areas
- General Chemistry
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry