Effect of silicon (Si) and aluminium (Al) doping on material’s hardness and oxidation resistance behaviours of chromium nitride (CrN) coatings: A NEXAFS investigation
Rahman, M.M., Jiang, Z-T, Yin, C-Y, Duan, A., Xie, Z., Mondinos, N., Amri, A. and Cowie, B. (2013) Effect of silicon (Si) and aluminium (Al) doping on material’s hardness and oxidation resistance behaviours of chromium nitride (CrN) coatings: A NEXAFS investigation. In: MUPSA Multidisciplinary Conference 2013, 3 October 2013, Murdoch University, Murdoch, W.A. p. 63.
Nowadays scientists and technologists are prompted to design and test novel coatings that can prevent mechanical damage to jet engines due to intrusion of airborne fine particulates, especially volcanic ash. Chromium nitride (CrN) is a prominent candidate, which can be engineered onto the surface of metals as a protective layer to enhance mechanical performances and durability of coated metals. Doped CrNs have widespread applications as protective coatings, including volcanic ash resistant coatings for jet engines. Excellent mechanical and chemical properties prevent these materials from wearing under harsh conditions. Previous investigations indicate that the mechanical hardness and oxidation resistance characteristics of the CrN coatings improved extensively with additional doping contents of silicon (Si) or aluminium (Al) to the CrN frame. In the present investigation, doped Cr (Si/Al) N coatings were prepared on steel substrates using a TEER UDP 650/4 closed field unbalanced magnetron sputtering technique. The Si and Al doping contents added were at 14.3, 21.2 and 28.5 at %, respectively. Synchrotron radiation near-edge X-ray absorption fine structure (NEXAFS) measurements were carried out in order to understand the local bonding structure and grain boundaries of the coating. The NEXAFS measurements were conducted at Al K-edge, S K-edge, Cr L-edge in Auger electron yield (AEY) and total fluorescence yield (TFY) modes. These provided significant information on the electronic structures and the bonding states of CrN matrix with Al and Si doping that assist understanding of the effects of local bonding states and grain boundaries of CrN frame in relation to the mechanical strength and oxidation resistance of the coatings. The data presented here will provide valuable insights on the local structures of dopants in relation to the material’s properties, leading to the development of superhard and corrosion-resistant coatings.
|Publication Type:||Conference Paper|
|Murdoch Affiliation:||School of Engineering and Energy|
|Publisher:||Murdoch University Postgraduate Student Association|
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