Accurate residual stress measurement as a function of depth in environmental barrier coatings via a combination of X-ray diffraction and Raman spectroscopy. Issue 8 (1st June 2020)

• Record Type: Journal Article
• Authors: Ye, Cheng; Jiang, Peng
• Is Part Of: Ceramics international. Volume 46:Issue 8(2020)Part B
• Page Start: 12613
• Page End: 12617
• Publication Date: 2020-06-01
• Subjects: Environmental barrier coating -- Residual stress -- X-ray diffraction -- Laser Raman spectroscopy; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2020.02.025
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: This study examined the properties of the latest generation of rare earth silicate environmental barrier coating system (EBCs). By combining X-ray diffraction and Raman spectroscopy, a novel and efficient method was developed to measure residual stress in EBCs produced by slurry coating. A 633-nm-wavelength laser beam from the confocal microlaser of a Raman spectrometer was focused on the cross-section of samples, and the spectra were recorded. We performed non-linear multi-peak spectrum fitting with the Lorenz function to obtain the peak shift of the EBC top coat at 5 μm intervals as a function of depth. We then obtained the stress distribution along the depth by calibrating the stress value on the surface via X-ray diffraction. The residual stress in the coating which endured high temperature, water, and oxygen corrosion without serious damage, was non-uniform and compressive. The stress at the bottom of the coating was approximately −275 MPa, decreasing towards the surface. A sudden shift in stress value was observed in the distribution of the residual stress, which was attributed to residual stress relaxation caused by microscopic pores contained within the coating.