A study of the nanostructure and hardness of electron beam evaporated TiAlBN Coatings

THIN SOLID FILMS

卷:518

Article

Baker, M. A.¹  Monclus, M. A.²  Rebholz, C.³  Gibson, P. N.⁴  Leyland, A.⁵  Matthews, A.⁵ 

[1] Univ Surrey, Fac Engn & Phys Sci, Surface Anal Lab, Guildford GU2 7XH, Surrey, England

[2] Natl Phys Lab, Teddington TW11 0LW, Middx, England

[3] Univ Cyprus, Dept Mech & Mfg Engn, CY-1678 Nicosia, Cyprus

[4] Joint Res Ctr, Inst Hlth & Consumer Protect, I-21027 Ispra, VA, Italy

[5] Univ Sheffield, Dept Mat Engn, Sheffield S1 3JD, S Yorkshire, England

关键词: Nanocomposites;    Thin films;    Hardness;    TiAlBN;    X-ray photoelectron spectroscopy;    X-ray diffraction;    Transmission electron microscopy;   

DOI  :  10.1016/j.tsf.2009.12.109

来源: Elsevier

【 摘 要 】

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 degrees 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)B-2 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-ER 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. (C) 2010 Elsevier B.V. All rights reserved.

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