Effects of Nano-Al₂O₃p on Thermal Shock Behaviors of NiCoCrAlY Coatings by Laser Cladding

Abstract:

NiCoCrAlY coatings strengthened by different content of nano-Al2O3p, using crosscurrent CO2 laser, were prepared on Ni-based superalloy substrates, and thermal shock behaviors of these coatings were investigated by cycling between 1050°C and room temperature (forced water quenching).The results show that the thermal shock resistances of nano-Al2O3p-added coatings are definitely better than that without adding nano-Al2O3p. Among the nano-Al2O3p-added coatings, the coating added with 0.5wt% nano-Al2O3p performs best. After 10 thermal shock cycles, the spalled and spalling area in the oxide scale of the no-nano-Al2O3p coating reaches up to 27.7%, and the main failure form of the oxide scale is an expanding unit-spalling type in thermal shock cycles. While the area in the oxide scale of nano-Al2O3p-added coatings is only 10%~60% to the no-nano-Al2O3p one, and the failure of these oxide scales is mainly in the form of unit-spalling type. After 100 thermal shock cycles, many cracks turn up in the cross-section of the no-nano-Al2O3p coating, including propagating crack and internal crack. While no internal crack appeared in nano-Al2O3p-added coatings, and the propagating cracks are smaller than no-nano-Al2O3p one.

• Periodical: Advanced Materials Research (Volumes 79-82)
• Pages: 779-782
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.79-82.779
• Online since: August 2009
• Authors: Hong Yu Wang, Dun Wen Zuo, Y.B. Sun, Ming Min Huang
• Keywords: Laser Cladding, Nano-Al₂O₃p, Thermal Barrier Coating (TBC), Thermal Shock

References

[1] C.B. Liu, F. Lin, and X.L. Jiang: The Chinese Journal of Nonferrous Metals Vol. 17 (2007), p.1.

[2] H. Zhang and Y.Z. He: Journal of Anhui University of Technology Vol. 23 (2006), p.21.

[3] C. BEZENCON, A. SCHNELL, and W. KURZ. Scripta Materialia, Vol. 49 (2003), p.705.

[4] H.Y. Wang, D.W. Zuo, and D.S. Li, China Patent ZL200710024996.X. (2009).

[5] H.Y. Wang, D.W. Zuo, and G.M. Jiao, China Patent CN200710135477. 0. (2008).

[6] G. Zhang, Y.N. Wu, and Y. Liang: Laser Technology Vol. 26 (2002), p.334.