Key Laboratory of Green Chemistry & Technology of the Ministry of Education, College of Chemistry, Sichuan University , Chengdu 610064, P. R. China.
ACS Appl Mater Interfaces. 2014 Oct 8;6(19):17157-65. doi: 10.1021/am5048762. Epub 2014 Sep 19.
To inhibit the metal catalytic coking and improve the oxidation resistance of TiN coating, rutile TiO2 coating has been directly designed as an efficient anticoking coating for n-hexane pyrolysis. TiO2 coatings were prepared on the inner surface of SS304 tubes by a thermal CVD method under varied temperatures from 650 to 900 °C. The rutile TiO2 coating was obtained by annealing the as-deposited TiO2 coating, which is an alternative route for the deposition of rutile TiO2 coating. The morphology, elemental and phase composition of TiO2 coatings were characterized by SEM, EDX and XRD, respectively. The results show that deposition temperature of TiO2 coatings has a strong effect on the morphology and thickness of as-deposited TiO2 coatings. Fe, Cr and Ni at.% of the substrate gradually changes to 0 when the temperature is increased to 800 °C. The thickness of TiO2 coating is more than 6 μm and uniform by metalloscopy, and the films have a nonstoichiometric composition of Ti3O8 when the deposition temperature is above 800 °C. The anticoking tests show that the TiO2 coating at a deposition temperature of 800 °C is sufficiently thick to cover the cracks and gaps on the surface of blank substrate and cut off the catalytic coke growth effect of the metal substrate. The anticoking ratio of TiO2 coating corresponding to each 5 cm segments is above 65% and the average anticoking ratio of TiO2 coating is up to 76%. Thus, the TiO2 coating can provide a very good protective layer to prevent the substrate from severe coking efficiently.
为了抑制金属催化结焦并提高 TiN 涂层的抗氧化性，已将金红石 TiO2 涂层直接设计为正庚烷热解的有效抗焦涂层。通过热 CVD 法在 650 至 900°C 的不同温度下在 SS304 管的内表面上制备 TiO2 涂层。通过对沉积的 TiO2 涂层进行退火来获得金红石 TiO2 涂层，这是沉积金红石 TiO2 涂层的替代方法。通过 SEM、EDX 和 XRD 分别对 TiO2 涂层的形貌、元素和相组成进行了表征。结果表明，TiO2 涂层的沉积温度对沉积的 TiO2 涂层的形貌和厚度有很强的影响。当温度升高到 800°C 时，基体中的 Fe、Cr 和 Ni 逐渐变为 0。金相观察表明，TiO2 涂层的厚度超过 6 μm 且均匀，当沉积温度高于 800°C 时，薄膜具有非化学计量比的 Ti3O8 组成。抗焦试验表明，沉积温度为 800°C 的 TiO2 涂层足够厚，可以覆盖空白基底表面的裂缝和间隙，并切断金属基底的催化焦生长效应。每个 5 cm 段对应的 TiO2 涂层的抗焦率均高于 65%，TiO2 涂层的平均抗焦率高达 76%。因此，TiO2 涂层可以为防止基底严重结焦提供非常好的保护层。
