Oxidation behaviors of Ni-Cr-Al superalloy foams at 1 000 °C in air

TANG Hui-ping(汤慧萍)¹, WANG Yan(王岩)², LIU Yong(刘咏)³, LI Wei-jie(李维杰)⁴, HAN Chao(韩朝)⁴

(1. State Key Laboratory of Porous Metals Materials, Northwest Institute for Nonferrous Metal Research,
Xi’an 710016, China;
2. School of Aeronautics and Astronautics, Central South University, Changsha 410083, China;
3. State Key Laboratory of Powder Metallurgy (Central South University), Changsha 410083, China;
4. Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong,
NSW 2522, Australia)

Abstract:The oxidation behaviors of Ni-16Cr-xAl (x=4.5%, 9.0%, mass fraction) superalloy foams in air at 1 000 °C were investigated. The effects of Al content on the resistance to high temperature oxidation were examined. The oxidation mechanisms of the foams were discussed. The results show that the resistance to the oxidation of the Ni-16Cr-xAl based alloy at 1 000 °C increases with the content of Al increasing from 4.5% to 9.0%. Complex oxide products are formed on the surface of the superalloy foams after the oxidation. Cr₂O₃ and Al₂O₃ are the predominant oxides for the scales of the foams with 4.5% Al and 9% Al, respectively. Excellent high temperature oxidation resistance and superior pore conformation stability for the Ni-16Cr-xAl based superalloy foam with 9% Al can be mainly attributed to the formation of relatively continuous and protective Al₂O₃ oxides on the surface of the foam.

Key words:Ni-Cr-Al based superalloy foam？ high temperature oxidation？ oxide scale？ pore conformation stability