Next Article in Journal
On the Importance of Combined Scratch/Acoustic Emission Test Evaluation: SiC and SiCN Thin Films Case Study
Previous Article in Journal
Evolution of Calcareous Deposits and Passive Film on 304 Stainless Steel with Cathodic Polarization in Sea Water
Article Menu
Issue 5 (May) cover image

Export Article

Open AccessArticle

Influences of Cr and Co on the Growth of Thermally Grown Oxide in Thermal Barrier Coating during High-Temperature Exposure

School of Reliability and Systems Engineering, Beihang University, Haidian District, Beijing 100191, China
*
Author to whom correspondence should be addressed.
Coatings 2018, 8(5), 195; https://doi.org/10.3390/coatings8050195
Received: 7 February 2018 / Revised: 6 May 2018 / Accepted: 18 May 2018 / Published: 22 May 2018
  |  
PDF [5656 KB, uploaded 22 May 2018]
  |  

Abstract

Thermal barrier coating (TBC) is a critical material in the aerospace domain to increase the lifetime of gas turbine components subjected to thermal load. The properties of TBC are strongly related to the growth of thermally grown oxide (TGO) whose main constituent is Al2O3. However, the oxidation of Cr and Co can affect the growth of TGO, which is not studied sufficiently. In this paper, high-temperature exposure at 1000 °C was performed to investigate the effect of Cr and Co oxides on TGO growth. The morphology and composition analysis of the interface between the ceramic top coat and the bond coat (TC/BC) were investigated by using scanning electron microscopy (SEM) and the energy dispersion spectrum (EDS). The thermodynamics and kinetics of oxidation were analyzed. The results indicated that the oxidation kinetics basically followed the sub-parabolic law with exposure time. Additionally, the major factor affecting the formation of oxides was the diffusion rate at the initial stage of exposure, then oxides depended on thermodynamics, and the oxidation was influenced by both of them in the last stage. The major elements to be oxidized were different at different stages. Moreover, the replacement reaction of Cr2O3 and the phase conversion of Al2O3 resulted in thickness variations of the TGO and Al-depleted zone during high-temperature exposure. View Full-Text
Keywords: thermal barrier coating (TBC); high-temperature exposure; thermally grown oxide (TGO); Cr oxide; oxidation kinetics thermal barrier coating (TBC); high-temperature exposure; thermally grown oxide (TGO); Cr oxide; oxidation kinetics
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Zhang, W.; Zhang, J.; Wang, H.; Lou, W.; Liu, X. Influences of Cr and Co on the Growth of Thermally Grown Oxide in Thermal Barrier Coating during High-Temperature Exposure. Coatings 2018, 8, 195.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Coatings EISSN 2079-6412 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top