Novel Fe-Based Amorphous Composite Coating with a Unique Interfacial Layer Improving Thermal Barrier Application

• Published in: ACS applied materials & interfaces Vol. 13; no. 19; pp. 23057 - 23066
• Main Authors: Zhou, Zheng, Han, Feng-Xi, Yao, Hai-Hua, Li, Yan-Ze, Yang, Yan-Ge, Guo, Xing-Ye, Tan, Zhen, Xue, Yun-Fei, He, Ding-Yong, Wang, Lu
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 19.05.2021
• Subjects: Surfaces, Interfaces, and Applications; Fe-based amorphous alloy; composite coating; fracture toughness; thermal conductivity; interfacial layer
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.0c22868

To improve thermal barrier applications in advanced vehicle engines, a novel Fe-based amorphous composite coating was designed by introducing ceramic oxides and was prepared by atmospheric plasma spraying (APS). The microstructure and related properties of the as-deposited coating were investigated in detail. The composite coating comprises a well-formed FeCrNbBSi amorphous metallic matrix and dispersed yttria-stabilized zirconia (YSZ) splats. A unique Si-oxide interfacial layer with a thickness of several nanometers and an amorphous structure forms between the metallic matrix and ceramic phase, which is attributed to a combination of multiple effects. The composite coating displays extremely low thermal conductivity from 2.28 W/mK at 100 °C to 3.36 W/mK at 600 °C and can increase the surface temperature of the piston crown by 18.93 °C, which implies a significant means of enhancing the power efficiency. The improved thermal barrier ability of the composite coating is revealed as the crucial effect of the Si-oxide interfacial layer, which induces an increased interfacial thermal resistance. The fracture toughness of the composite coating remains at 3.40 MPa·m1/2, comparable to that of the monolithic amorphous coating, 3.74 MPa·m1/2, which is closely related to the formation of a Si-oxide layer and its nanoscale thickness. Therefore, the Fe-based amorphous composite coating developed here demonstrates great potential as an innovative metal-based thermal barrier coating for application in vehicle engines and provides specific inspiration for future works exploring the interfacial engineering of coating.