Atomic Layer Deposition of TiO2 Thin Films on the Inner Walls of Steel Tubes Increases Anti-coking Properties

Changfa Zhu; Fei Ma; Zhengfei Dai; Dayan Ma

doi:10.1021/acsomega.0c05195

Atomic Layer Deposition of TiO₂ Thin Films on the Inner Walls of Steel Tubes Increases Anti-coking Properties

ACS Omega. 2020 Dec 2;5(49):32102-32111. doi: 10.1021/acsomega.0c05195. eCollection 2020 Dec 15.

Authors

Changfa Zhu¹, Fei Ma¹, Zhengfei Dai¹, Dayan Ma¹

Affiliation

¹ State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, People's Republic of China.

Abstract

To suppress catalytic coking, TiO₂ passivation films were deposited on the inner walls of SS316 stainless steel tubes by atomic layer deposition (ALD). Indentation test results showed a platform on the indentation curve of TiO₂ films grown over 2000 ALD cycles due to internal stress-induced microcracks. In coking experiments, the TiO₂-coated tubes exhibited a higher heat flux and lower pressure difference than bare ones. Analysis of the coking surface revealed that TiO₂ thin film passivation can reduce the size and number of particulate deposits. At the same time, passivation treatment inhibits the formation of filamentous carbon and improves anti-coking performance by reducing the ability of the tube to adsorb amorphous deposition products. The coking surfaces of TiO₂-coated tubes had less graphitization, indicating that the coking products had fewer defects and lower activated carbon contents.