On the possibility of synthesizing multilayered coatings in the (Ti,Al)N system by RGPP: A microstructural study

• Published in: Surface & coatings technology Vol. 374; pp. 845 - 851
• Main Authors: El Mouatassim, A., Pac, M.-J., Pailloux, F., Amiard, G., Henry, P., Rousselot, C., Eyidi, D., Tuilier, M.-H., Cabioc'h, T.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 25-09-2019; Elsevier BV; Elsevier
• Subjects: (Ti-Al-N) system; Aluminum; Buffer layers; Conditioning; Electron diffraction; Engineering Sciences; Flow velocity; Intermetallic compounds; Magnetron sputtering; Materials; Microstructure; Multilayers; Nitrogen; Radio frequency; Substrates; Synthesis; TEM; Thin films; Titanium aluminides; Thin films; Multilayers; (Ti-Al-N) system; Microstructure; TEM
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2019.06.071

Radiofrequency magnetron sputtering combined with reactive gas pulsing process was used to synthesize two titanium aluminum nitride multilayer films using a periodically controlled nitrogen flow rate changing from 0.4 to 1 sccm (sample S04-1) and from 0 to 1 sccm (sample S0-1). A metallic TiAl buffer layer was deposited on the etched substrates before the deposition to enhance their adhesion. The films were characterized using mainly transmission electron microscopy and electron diffraction. The role of the crystallinity of the buffer TiAl metallic layer deposited before gas introduction on the growth orientations is emphasized. It is shown that the formation of a multilayer structure is conditioned by stopping periodically and completely the nitrogen flow rate. Particular attention is paid to the role that residual oxygen can play on the microstructure and to transient regime that occurs when the flow rate drops from 1 sccm to 0 sccm.
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•Reactive gas pulsing process is powerful for multilayered TiAlN coatings synthesis.•Multilayered films are only obtained when stopping regularly the nitrogen flow rate.•Residual presence of oxygen strongly modifies the microstructure of the coatings.