Enhancing the cavitation erosion resistance of D8m-Ta5Si3 nanocrystalline coatings through Al alloying

Jiang Xu; Wei Liu; Shuyun Jiang; Paul Munroe; Zong-Han Xie

doi:10.1016/j.ultsonch.2018.09.008

Enhancing the cavitation erosion resistance of D8_m-Ta₅Si₃ nanocrystalline coatings through Al alloying

Ultrason Sonochem. 2019 Jan:50:138-156. doi: 10.1016/j.ultsonch.2018.09.008. Epub 2018 Sep 5.

Authors

Jiang Xu¹, Wei Liu², Shuyun Jiang³, Paul Munroe⁴, Zong-Han Xie⁵

Affiliations

¹ Department of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016, PR China. Electronic address: xujiang73@nuaa.edu.cn.
² Department of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016, PR China.
³ Department of Mechanical Engineering, Southeast University, 2 Si Pai Lou, Nanjing 210096, PR China.
⁴ School of Materials Science and Engineering, University of New South Wales, NSW 2052, Australia.
⁵ School of Mechanical & Electrical Engineering, Wuhan Institute of Technology,693 Xiongchu Avenue, Wuhan 430073, PR China; School of Mechanical Engineering, University of Adelaide, SA 5005, Australia.

PMID: 30219353
DOI: 10.1016/j.ultsonch.2018.09.008

Abstract

To investigate the effects of Al alloying on the erosion-corrosion resistance of β-Ta₅Si₃, both a β-Ta₅Si₃ coating and an Al-alloyed β-Ta₅(Si_0.83Al_0.17)₃ coating were synthesized on a 316 substrate by the double cathode glow discharge technique. The phase constitution, composition and microstructure of the two coatings were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The two coatings were composed of nearly rounded D8_m-β-Ta₅Si₃ grains with an average size of ∼4 nm, and after the addition of Al, the preferred growth orientation for the β-Ta₅Si₃ coating changed from (4 0 0) to (0 0 2). The hardness, elastic modulus and contact damage resistance of the coatings were measured using a nanoindentation tester. The results showed that Al alloying improved the contact damage resistance of β-Ta₅Si₃ with only a slight decrease in hardness. The erosion-corrosion behavior of the two coatings was performed in a 3.5 wt% NaCl solution containing a 12 wt% concentration of silica sand under two phase slurry flow condition and in a 3.5 wt% NaCl solution under ultrasonic cavitation erosion conditions. This revealed that the Al alloyed β-Ta₅Si₃ has a higher resistance to both erosion-corrosion and ultrasonic cavitation erosion as compared to the binary β-Ta₅Si₃ coating.

Keywords: EIS; Erosion–corrosion; Potentiodynamic polarization; Refractory metal silicides; Ultrasonic cavitation erosion.