Mullite-gadolinium silicate environmental barrier coatings for melt infiltrated SiC/SiC composites

作者：Ramasamy Sivakumar^*; Tewari Surendra N; Lee Kang N; Bhatt Ramakrishna T; Fox Dennis S

来源：Surface and Coatings Technology, 2011, 205(12): 3578-3581.

DOI：10.1016/j.surfcoat.2010.12.031

• Fiber reinforced composites
• Environmental barrier coatings
• Sintering
• Oxidation
• Thermal cycling
• Electron microscopy

Slurry based mullite/gadolinium silicate (Gd(2)SiO(5)) environmental barrier coatings (EBCs) were developed for melt infiltrated (MI) SiC/SiC composites. The coating chemically adhered well on the substrates. Thermal cycling of uncoated MI-SiC/SiC composites conducted between 1350 degrees C and 90 degrees C (one hour hot and 15 min cold) in a 96.5% H(2)O-3.5% O(2) environment caused severe oxidation damage after 100 cycles resulting in the formation of dense silica layer of about 25 mu m maximum thickness. Mullite/Gd(2)SiO(5) EBCs provided excellent protection to MI-SiC/SiC against moisture damage with significantly less oxidation of the substrate: only about a 2 mu m thick oxide layer formed even after 400 similar thermal cycles. The hair-line cracks formed at the coating/substrate interface after 400 cycles causing partial coating de-lamination.

• 出版日期2011-3-15