The influence of low-energy ion bombardment on the microstructure development and mechanical properties of TiBx coatings
Authors | |
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Year of publication | 2011 |
Type | Article in Periodical |
Magazine / Source | Vacuum |
MU Faculty or unit | |
Citation | |
Doi | http://dx.doi.org/10.1016/j.vacuum.2010.12.011 |
Field | Plasma physics |
Keywords | TiBx coatings; Magnetron sputtering; Nanocomposite system; Texture; Hardness |
Description | The influence of the deposition parameters on the growth, structure and mechanical properties of the TiBx coatings are studied. The TiBx coatings represent a nanocomposite system, in which random or oriented TiB2 nanocrystallites are embedded in an amorphous matrix as is revealed by cross-sectional transmission electron microscopy. We show that low-energy ion bombardment (Ei) of growing TiBx coating influences the preferred orientation of TiB2 crystallites. The increasing of ion current density (is) by means of negative substrate bias voltage (Us) leads to change from random to the (0001) preferred crystal orientation whereby the electrical biasing promotes crystal growth in the coating and the (0001) texture appears gradually during the film growth. Together with the (0001) preferred orientation selection the composition B/Ti ratio was changed from 2.9 (floating potential, Ei=8eV) to 2.4 (Ei=94eV). The highest amount of oriented (0001) crystallites and highest hardness H=53 GPa exhibit TiB2 coatings deposited at Ei=94eV and is= 2,69 mA.cm-2. |
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