TEM Structure, Nanomechanical Property, and Adhesive Force of Magnetron-Sputtered Cr-DLC Coating on a Nitrided Ti₆Al₄V Alloy

Abstract

A magnetron-sputtered Cr-diamond-like carbon (DLC) coating was deposited on nitrided Ti 6 Al 4 V alloys (TAs) by employing the CrN interlayer. The physical and chemical characteristics of the obtained coating were systematically studied using scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, high-resolution transmission electron microscopy, atomic force microscopy, X-ray diffraction, nanoindentation, and scratch tests. The results show that the Cr-DLC coating is an amorphous structure of carbon (C), and the Cr clusters are dispersed in the Cr-DLC coating. Raman analysis also confirms the existence of G and D peaks in the Cr-DLC coating. The Cr-DLC coating presents outstanding nanomechanical properties, and its nanohardness and elastic modulus are 19.29 and 168.8 GPa, respectively, which are contributed to the formation of diamond. The adhesive force of the Cr-DLC coating with the nitrided TA is determined to be 20.70 N by the scratch test, which is improved by the Cr−C bond of the CrN interlayer at a binding energy of 283.4 eV.

Photoelectrochemical and Electrochemical Activity of Anodic Semitransparent Aligned and Spaced Titania Nanotubes Formed out of Titanium–Silver Alloys

“…In fact, this transition layer concatenates the sputtered film and substrate, which improves the adhesive forces between the coated film and the TCO. 12 Although TNT grown by anodic oxidation onto TCO are regarded as promising electrodes for PEC devices, the poor absorption of titania in visible light due to the wide band gap limits their solar-to-electricity conversion efficiency (only 7%). 13 Two major approaches cover (i) broadening the titania absorption spectrum to the visible region and (ii) promoting the electron−hole separation through modification of the tubular structure with metal nanoparticles.…”

“…This strategy has been explored by Kim et al, Büttner et al, and Krumpmann et al to produce Ti/TCO substrates and is considered to be crucial in the fabrication of crack-free and more regular TNT with tunable geometry on TCO. In fact, this transition layer concatenates the sputtered film and substrate, which improves the adhesive forces between the coated film and the TCO …”

Tailoring Mechanical Properties of a-C:H:Cr Coatings

“…The rise in sp 2 graphitization by doping metal elements and partly hard carbide phase dispersion in amorphous carbon explains this phenomenon [11]. Among many metallic elements, chromium (Cr), in combination with carbon, presents attractive mechanical properties (exceptionally stable friction performance and toughness) in a-C coatings [12][13][14].…”