Title: Niobium coated Ti-Al alloy: improvement of tribological behaviour, oxidation resistance and flame retardancy

Authors: Xiangfei Wei; Pingze Zhang; Dongbo Wei; Hongyuan Zhao; Tomasz Liskiewicz

Addresses: College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, 211106, China ' College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, 211106, China ' College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, 211106, China ' School of Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, UK ' School of Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, UK

Abstract: Double glow plasma (DGP) coatings were recommended for metallic components to mitigate the damage induced by complex working conditions. In this paper, A Ti-Al alloy was coated with niobium (Nb) via a DGP process to enhance its anti-oxidation properties, wear resistance and flame retardancy. The results showed that the Nb-coated Ti-Al alloy mainly comprised Nb, AlNb2, AlMoTi2 and β-Ti phases. Room temperature sliding-friction tests indicated that the Nb-coated Ti-Al alloy exhibited a stable friction coefficient of an average value of 0.25, whilst the same value for via the uncoated Ti-Al alloy was around 0.45. High-temperature oxidation tests revealed compact oxide grains without cracks after the 100 h test, indicating good oxidation resistance. An ablation test showed that the Nb-coated Ti-Al alloy exhibited excellent flame retardancy, with the ablation time of the Nb-coated Ti-Al alloy at 1.62 times that of the uncoated Ti-Al base alloy. The alloys tribological behaviour, oxidation resistance and flame retardancy mechanisms are discussed in detail in this paper.

Keywords: double glow plasma; DGP coatings; Nb-coated Ti-Al; wear resistance; high temperature oxidation resistance; flame retardancy; niobium coatings; tribological behaviour; tribology; titanium alloys; aluminium; sliding friction tests; friction coefficient.

DOI: 10.1504/IJSURFSE.2016.081031

International Journal of Surface Science and Engineering, 2016 Vol.10 No.6, pp.559 - 569

Received: 28 Nov 2015
Accepted: 24 Dec 2015
Published online: 19 Dec 2016 *

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