不锈钢表面TiN、TiO_2涂层化学气相沉积制备及抑焦性能研究

Preparation of TiN and TiO_2 Coatings on Stainless Steel Surface by Chemical Vapor Deposition and Their Anti-coking Property

为抑制不锈钢材料表面催化结焦,采用常压化学气相沉积法,实现了在10 mm×10 mm×0.9 mm的310S型不锈钢试样表面TiN和TiO_2涂层沉积,沉积温度为850℃,时间为2.5 h。通过SEM、EDS和XRD分析了涂层的形貌特征和组织结构,结果显示,TiN和TiO_2涂层表面均匀完整,粒子结合紧密;氮化钛为立方晶相结构,Ti和N原子比约为1:1,氧化钛的组成为TiO_(1.7)。分别以正己烷、环己烷、苯和RP-3为原料,采用自制的常压裂解装置对2种涂层的抑焦效果进行了评价,结果表明,TiN涂层对4种原料的结焦抑制率分别为99.91%,86.19%,72.36%和94.68%,而TiO_2涂层则为83.39%,85.77%,57.78%和68.57%,TiN涂层具有更优的抑焦性能;310S空白片表面以丝状焦为主,TiN和TiO_2涂层表面以吸附气相结焦为主。

In order to avoid the catalytic cokes forming, the Ti N and TiO2 coatings were deposited on the surface of the 310 S stainless steel flake with the diameter of 10×10×0.9 mm by atmospheric pressure chemical vapor deposition. The deposition temperature was 850 °C for Ti N and TiO2, and the deposition time was 2.5 h. The morphologies and structures of the coatings were analyzed by SEM, EDS and XRD. An atmospheric pressure cracking system was set up for evaluating the anti-coking property of TiN and TiO2 coating with n-hexane, cyclohexane, benzene and RP-3 as feedstock. The results show that the TiN and TiO2 coatings are continuous, close-packed and homogeneous; the titanium nitride in the coating has cub phase, Ti and N atomic ratio in the titanium nitride coating is 1：1, and the titanium oxide in the coating is the Ti2O3~Ti3O5 stoichiometrically. TiN and TiO2 coatings exhibit an excellent anti-coking performance. The anti-coking ratio of Ti N coating for n-hexane, cyclohexane, benzene and RP-3 is 99.91%, 86.19%, 72.36% and 94.68%, respectively; correspondingly, the anti-coking ratio of TiO2 coating is 83.39%, 85.77%, 57.78% and 68.57%, respectively. Hence, the TiN coating has a better anti-coking performance than TiO2 coating. The morphologies of the cokes on 310 S surface are mainly filamentous cokes, and TiN and TiO2 coatings inhibit the filamentous cokes formation.