Effect of oxygen incorporation on the structure and elasticity of Ti-Al-O-N coatings synthesized by cathodic arc and high power pulsed magnetron sputtering

Abstract

Ti-Al-O-N coatings were synthesized by cathodic arc and high power pulsed magnetron sputtering. The chemical composition of the coatings was determined by means of elastic recoil detection analysis and energy dispersive X-ray spectroscopy. The effect of oxygen incorporation on the stress-free lattice parameters and Young's moduli of Ti-Al-O-N coatings was investigated by X-ray diffraction and nanoindentation, respectively. As nitrogen is substituted by oxygen, implications for the charge balance may be expected. A reduction in equilibrium volume with increasing O concentration is identified by X-ray diffraction and density functional theory calculations of Ti-Al-O-N supercells reveal the concomitant formation of metal vacancies. Hence, the oxygen incorporation-induced formation of metal vacancies enables charge balancing. Furthermore, nanoindentation experiments reveal a decrease in elastic modulus with increasing O concentration. Based on ab initio data, two causes can be identified for this: First, the metal vacancy-induced reduction in elasticity; and second, the formation of, compared to the corresponding metal nitride bonds, relatively weak Ti-O and Al-O bonds. V C 2014 AIP Publishing LLC.

Unprecedented thermal stability of inherently metastable titanium aluminum nitride by point defect engineering

“…The oxygen content was 0.5 ± 0.1 at% for all samples. Since oxygen can be dissolved on the nitrogen sublattice [21] the metal vacancy concentrations can be determined from the non-metal to metal ratios. These are 1.14 ± 0.04 for the sample deposited using a poisoned target and 1.08 ± 0.04, 1.04 ± 0.04 and 0.88 ± 0.03 for the samples positioned 50, 90 and 130 mm away from the nitrogen gas inlet during combinatorial reactive magnetron sputtering, respectively.…”

“…X-ray stress analysis (XSA) was done following the theory developed by Genzel for 001 -textured cubic crystals [47]. The fitting was done according to our previous work [21] and the elastic compliance was taken from Tasnádi et al [48].…”

“…Here, we utilize a newly developed combinatorial deposition setup using reactive gas gradients to continuously vary the nitrogen-to-metal ratio N/M in the thin film [21]. As shown schematically in Figure 1(b), the nitrogen gas inlet is placed at the short side of the rectangular magnetron.…”

Correlative theoretical and experimental investigation of the formation of AlYB14 and competing phases

“…The experimental details of the TOF-ERDA measurements can be found in Ref. 53 whereas the detection system and associated systematic uncertainties are discussed in a study by Zhang et al 54 The sample for TEM investigation was fabricated with a focused ion beam (FIB, FEI Helios 660) followed by a post thinning-process under illumination of 500 eV ion beam (Nanomil, Fischione). Furthermore to investigate the elemental and chemical structure of the thin film EDX spectroscopy mapping as well as electron energy loss spectroscopy spectrum imaging (EELS-SI) of the samples was acquired by analytical scanning TEM (STEM, FEI Titan 3 60-300, equipped with a Super-X EDX detector and a Dual-EELS Quantum ERS GIF).…”

From quantum to continuum mechanics: studying the fracture toughness of transition metal nitrides and oxynitrides

“…For example, in polymerforming operations, they exhibit a combination of outstanding wear resistance and chemical stability against polymer adhesion [2]. While the elastic properties of such coatings have been previously investigated [3][4][5], the relationship between chemical composition and fracture toughness has only been explored selectively [6,7]. Given the wide possibilities in anion and cation chemistry, it is essential to establish a physical model linking the local structure and composition of the coatings with their fracture behaviour.…”