Oxidation of Single Crystalline Ti2AlN Thin Films between 300 and 900 °C: A Perspective from Surface Analysis

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• 作者：Zheng Zhang ; Jianwei Chai ; Hongmei Jin ; Jisheng Pan ; Lai Mun Wong ; Suo Hon Lim ; Michael B. Sullivan ; Shi Jie Wang
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：August 25, 2016
• 年：2016
• 卷：120
• 期：33
• 页码：18520-18528
• 全文大小：653K
• 年卷期：0
• ISSN：1932-7455

文摘

High temperature oxidation of 300 nm single crystalline Ti₂AlN MAX phase thin film deposited on MgO(111) substrate between 300 and 900 °C has been investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and mass spectrometry. As shown by XRD, Ti₂AlN remained structurally stable up to 700 °C, before it began to react with MgO substrate and ambient O₂ to form MgTi₂O₅ and MgAl₂O₄ at 900 °C. However, as revealed by XPS, oxidation of Ti₂AlN occurred at room temperature from its surface by forming TiO₂, TiN_xO_y and Al₂O₃ with surface enrichment of Al. This initial oxidation continued up to 300 °C, until Ti and Al in the surface layer (∼7.1 nm thick) have been completely oxidized into TiO₂ and Al₂O₃ at 500 °C, where Al in the subsurface preferentially diffused to the edges of the terraces and agglomerated into Al₂O₃ islands. At 700 °C and above, surface of Ti₂AlN lost its characteristic hexagonal terrace morphology by transforming into round islands as a result of high temperature oxidation. Mass spectrometry revealed that N in Ti₂AlN was released from the MAX thin film as N₂ and N₂O.