Structure and Wear Mechanisms of Nanostructured TiAlCN/VCN Multilayer Coatings

Abstract

Dry sliding wear of transition metal nitride coatings usually results in a dense and strongly adhered tribofilm on the worn surface. This paper presents detailed electron microscopy and Raman spectroscopy characterizations of the microstructure, a newly developed multilayer coating TiAlCN/VCN and its worn surface after pin‐on‐disc sliding wear against an alumina ball. The friction coefficient in a range of 0.38–0.6 was determined to be related to the environmental humidity, which resulted in a wear coefficient of the coating varying between 10−17 and 10−16 m3 · N−1 · m−1. TEM observation of worn surfaces showed that, when carbon was incorporated in the nitride coating, the formation of dense tribofilm was inhibited.

Tribological and oxidation behaviour of TiAlCN/VCN nanoscale multilayer coating deposited by the combined HIPIMS/(HIPIMS-UBM) technique

“…The wear tracks in all cases seem to be very smooth except for the one generated at 200°C. The smooth wear track morphology can be attributed to the lubricating effect of oxides formed at the sliding junctions of the tribo-couple [18].…”

Electron Microscopy and Spectroscopy in the Analysis of Friction and Wear Mechanisms

“…Scanning electron microscopy (SEM), especially the high-resolution SEM equipped with field emission gun (FEG), can greatly increase the spatial resolution in microscopic observations as compared to OM. Owing to the high resolution, wear features can be observed down to sub-micron and nano-scales [21,[24][25][26]. Another obvious advantage of SEM is its large depth of focus, which allows imaging of three-dimensional features on most worn surfaces and wear particles.…”

“…The sample shown in this case study was a worn surface of a magnetron sputtered TiAlN/VN multilayer coating, which was tested in a ball-on-disc dry sliding wear against an alumina ball [14,[22][23][24] after 200,000 sliding cycles. The cross-sectional TEM foil sample was prepared through a procedure from manual grinding and polishing to ion milling using a PIPS instrument (Model: Gatan 691).…”

“…Several transition metal nitride coatings were developed to meet the requirements of metal-machining tools in different cutting conditions, including the binary TiN and CrN coatings, multicomponent coatings TiAlN, TiAlCrN, and TiAlCrYN, and nano-structured multilayer coatings TiAlN/CrN, TiAlN/VN, and TiAlCN/VCN [4,17,23,24,41,42]. The coatings were grown using an industrial-scale magnetron sputtering coating equipment, each under its own optimal deposition conditions.…”

Structure characterization and tribological study of magnetron sputtered nanocomposite nc-TiAlV(N,C)/a-C coatings

“…By incorporating carbon in the TiAlN/VN, the deposited coating was found to show substantially extended tool lifetime in dry machining a wrought aluminium alloy [30]. Preliminary research indicated that the outstanding performance should be attributed to the carbon-modified structure of the TiAlVCN coatings although detailed understanding was not available [31]. This paper reports comprehensive structural characterisation of the carbon-incorporated TiAlVCN coatings by using analytical and high resolution transmission electron microscopy (TEM) with electron energy loss spectroscopy (EELS), field emission gun scanning electron microscopy (FEG-SEM) energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Raman spectroscopy.…”