Oxidation of a polycrystalline titanium surface by oxygen and water
Oxidation of a polycrystalline titanium surface by oxygen and water
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DOI：
10.1016/s0039-6028(00)00420-9
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发表时间：
2000-06-20
期刊：
影响因子：
1.9
通讯作者：
Schwartz, J
中科院分区：
文献类型：
--
作者：
Lu, G;Bernasek, SL;Schwartz, J
利用X射线光电子能谱（XPS）、热脱附谱（TDS）和傅里叶变换反射-吸收红外光谱（FT-RAIRS）研究了150-850 K温度范围内多晶钛表面与氧和水分子的反应。在150 K时，O-2将Ti-0氧化为Ti-IV、Ti-III和Ti-II，但在此温度下Ti暴露于H2O仅产生Ti-II物质。在高于300 K的温度下，观察到Ti被H2O进一步氧化。在550-600 K时，两种分子的氧化作用达到最大值。在将氧化的钛加热到850 K以上时，氧化物层完全还原为Ti-0。在250 ~ 350 K温度范围内，Ti表面与水反应后，出现了羟基物种，它们主要以氢键形式存在。并在450-650 K的表面温度范围内隔离。深度剖析的O-2-氧化的Ti表面表明，Ti-IV/Ti-III物种占氧化物层的总厚度的约20%，并位于表面附近，而Ti-II具有更广泛的分布，并集中在靠近氧化物-金属界面。OH基团浓度在550 K油样品表面最大化，占总表面氧的约16%，随着OH浓度的降低进入钛氧化物的体积。(C)2000由Elsevier Science B. V.出版，保留所有权利。
Reactions of a well-characterized polycrystalline titanium surface with oxygen and water molecules at 150-850 K were studied in UHV by X-ray photoelectron spectroscopy (XPS), thermal desorption spectroscopy (TDS) and Fourier transform reflectance-absorption infrared spectroscopy (FT-RAIRS). At 150 K, O-2 oxidizes Ti-0 to Ti-IV Ti-III and Ti-II, but Ti exposure to H2O at this temperature produces only Ti-II species. At temperatures above 300 K, further oxidation of Ti by H2O was observed. Maximum oxidation by either molecule is achieved at 550-600 K. Upon heating the oxidized titanium above 850 K, the oxide layer is completely reduced to Ti-0. Hydroxyl species are identified on the Ti surface after reaction with H2O they appear to be mostly hydrogen bonded between 250 and 350 K. and isolated in the 450-650 K surface temperature range. Depth profiling of the O-2-oxidized Ti surface shows that Ti-IV/Ti-III species account for about 20% of the total thickness of the oxide layers and are located near the surface, while Ti-II has a broader distribution, and is concentrated close to the oxide-metal interface. The OH group concentration is maximized at 550 K oil the sample surface and accounts for about 16% of the total surface oxygen, with a decreasing concentration of OH into the bulk of the titanium oxides. (C) 2000 Published by Elsevier Science B.V. All rights reserved.