A study of the nanostructure and hardness of electron beam evaporated TiAlBN Coatings
Baker, MA, Monclus, MA, Rebholz, C, Gibson, PN, Leyland, A and Matthews, A (2010) A study of the nanostructure and hardness of electron beam evaporated TiAlBN Coatings THIN SOLID FILMS, 518 (15). 4273 - 4280. ISSN 0040-6090
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Official URL: http://dx.doi.org/10.1016/j.tsf.2009.12.109
TiAlBN coatings have been deposited by electron beam (EB) evaporation from a single TiAlBN material source onto AISI 316 stainless steel substrates at a temperature of 450 °C and substrate bias of − 100 V. The stoichiometry and nanostructure have been studied by X-ray photoelectron spectroscopy, X-ray diffraction and transmission electron microscopy. The hardness and elastic modulus were determined by nanoindentation. Five coatings have been deposited, three from hot-pressed TiAlBN material and two from hot isostatically pressed (HIPped) material. The coatings deposited from the hot-pressed material exhibited a nanocomposite nc-(Ti,Al)N/a-BN/a-(Ti,Al)B2 structure, the relative phase fraction being consistent with that predicted by the equilibrium Ti–B–N phase diagram. Nanoindentation hardness values were in the range of 22 to 32 GPa. Using the HIPped material, coating (Ti,Al)B0.29N0.46 was found to have a phase composition of 72–79 mol.% nc-(Ti,Al)(N,B)1 − x+ 21–28 mol.% amorphous titanium boride and a hardness of 32 GPa. The second coating, (Ti,Al)B0.66N0.25, was X-ray amorphous with a nitride+boride multiphase composition and a hardness of 26 GPa. The nanostructure and structure–property relationships of all coatings are discussed in detail. Comparisons are made between the single-EB coatings deposited in this work and previously deposited twin-EB coatings. Twin-EB deposition gives rise to lower adatom mobilities, leading to (111) (Ti,Al)N preferential orientation, smaller grain sizes, less dense coatings and lower hardnesses.
|Uncontrolled Keywords:||Nanocomposites, Thin films, Hardness, TiAlBN, X-ray photoelectron spectroscopy, X-ray diffraction, Transmission electron microscopy, DENSITY-FUNCTIONAL THEORY, BORON-NITRIDE COATINGS, THIN-FILMS, NANOCOMPOSITE COATINGS, ELASTIC-CONSTANTS, TITANIUM|
|Divisions:||Faculty of Engineering and Physical Sciences > Mechanical Engineering Sciences|
|Deposited By:||Symplectic Elements|
|Deposited On:||16 Nov 2011 11:24|
|Last Modified:||16 Feb 2013 14:44|
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