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| Autori principali: | , , , , , , , , |
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| Natura: | Preprint |
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2026
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| Accesso online: | https://arxiv.org/abs/2601.20691 |
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| _version_ | 1866911404534005760 |
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| author | Kümmerl, Pauline Nayak, Ganesh Kumar Leinenbach, Felix Czigány, Zsolt Primetzhofer, Daniel Kolozsvári, Szilárd Polcik, Peter Hans, Marcus Schneider, Jochen M. |
| author_facet | Kümmerl, Pauline Nayak, Ganesh Kumar Leinenbach, Felix Czigány, Zsolt Primetzhofer, Daniel Kolozsvári, Szilárd Polcik, Peter Hans, Marcus Schneider, Jochen M. |
| contents | The composition-dependent thermal stability of (Cr$_{0.47 \mp 0.03}$Al$_{0.53 \mp 0.03}$)$_{z}$(O$_{y}$N$_{1-y}$)$_{1-z}$ thin films with O concentrations of y = 0, 0.15, and 0.40 is investigated up to 1200 °C and then compared to (Ti$_{0.56}$Al$_{0.44}$)$_{z}$(O$_{y}$N$_{1-y}$)$_{1-z}$. X-ray diffraction reveals a thermal stability limit of 1150 °C independent of the O concentration, as witnessed by the formation of decomposition products, namely h-Cr$_{2}$N for (Cr$_{0.50}$Al$_{0.50}$)$_{0.49}$N$_{0.51}$ and c-Cr for both (Cr$_{0.48}$Al$_{0.52}$)$_{0.48}$(O$_{0.15}$N$_{0.85}$)$_{0.52}$ and (Cr$_{0.44}$Al$_{0.56}$)$_{0.46}$(O$_{0.40}$N$_{0.60}$)$_{0.54}$. Based on TEM and ERDA data, the thermal stability limit is extended to 1100 - 1150 °C. DFT calculations indicate that bond breaking limits the thermal stability. In (Cr,Al)N, N has the lowest activation energy for migration. Furthermore, the O vacancy formation energy is highest in (Cr,Al)(O,N). It has to be overcome to enable diffusion on the non-metal sublattice, which is necessary for forming decomposition products like w-AlN or c-Cr. However, once Cr-N bonds break, decomposition into h-Cr$_{2}$N and subsequent c-Cr together with N$_{2}$ is triggered. This results in N evaporation, generating sufficient non-metal vacancies that greatly enhance diffusion and render the extensive vacancy formation energies for non-metals irrelevant. This reduction of the activation energy for mass transport on the non-metal sublattice to the migration barrier causes the similar thermal stability in (Cr$_{0.47 \mp 0.03}$Al$_{0.53 \mp 0.03}$)$_{z}$(O$_{y}$N$_{1-y}$)$_{1-z}$. In contrast, Al bonds break first without creating non-metal vacancies in (Ti,Al)(O,N). Thus, the high O vacancy formation energy in (Ti,Al)(O,N) significantly increases the thermal stability compared to (Ti,Al)N as well as the here investigated films. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2601_20691 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Impact of O concentration on the thermal stability and decomposition mechanism of (Cr,Al)N compared to (Ti,Al)N thin films Kümmerl, Pauline Nayak, Ganesh Kumar Leinenbach, Felix Czigány, Zsolt Primetzhofer, Daniel Kolozsvári, Szilárd Polcik, Peter Hans, Marcus Schneider, Jochen M. Materials Science The composition-dependent thermal stability of (Cr$_{0.47 \mp 0.03}$Al$_{0.53 \mp 0.03}$)$_{z}$(O$_{y}$N$_{1-y}$)$_{1-z}$ thin films with O concentrations of y = 0, 0.15, and 0.40 is investigated up to 1200 °C and then compared to (Ti$_{0.56}$Al$_{0.44}$)$_{z}$(O$_{y}$N$_{1-y}$)$_{1-z}$. X-ray diffraction reveals a thermal stability limit of 1150 °C independent of the O concentration, as witnessed by the formation of decomposition products, namely h-Cr$_{2}$N for (Cr$_{0.50}$Al$_{0.50}$)$_{0.49}$N$_{0.51}$ and c-Cr for both (Cr$_{0.48}$Al$_{0.52}$)$_{0.48}$(O$_{0.15}$N$_{0.85}$)$_{0.52}$ and (Cr$_{0.44}$Al$_{0.56}$)$_{0.46}$(O$_{0.40}$N$_{0.60}$)$_{0.54}$. Based on TEM and ERDA data, the thermal stability limit is extended to 1100 - 1150 °C. DFT calculations indicate that bond breaking limits the thermal stability. In (Cr,Al)N, N has the lowest activation energy for migration. Furthermore, the O vacancy formation energy is highest in (Cr,Al)(O,N). It has to be overcome to enable diffusion on the non-metal sublattice, which is necessary for forming decomposition products like w-AlN or c-Cr. However, once Cr-N bonds break, decomposition into h-Cr$_{2}$N and subsequent c-Cr together with N$_{2}$ is triggered. This results in N evaporation, generating sufficient non-metal vacancies that greatly enhance diffusion and render the extensive vacancy formation energies for non-metals irrelevant. This reduction of the activation energy for mass transport on the non-metal sublattice to the migration barrier causes the similar thermal stability in (Cr$_{0.47 \mp 0.03}$Al$_{0.53 \mp 0.03}$)$_{z}$(O$_{y}$N$_{1-y}$)$_{1-z}$. In contrast, Al bonds break first without creating non-metal vacancies in (Ti,Al)(O,N). Thus, the high O vacancy formation energy in (Ti,Al)(O,N) significantly increases the thermal stability compared to (Ti,Al)N as well as the here investigated films. |
| title | Impact of O concentration on the thermal stability and decomposition mechanism of (Cr,Al)N compared to (Ti,Al)N thin films |
| topic | Materials Science |
| url | https://arxiv.org/abs/2601.20691 |