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Determination of the sp3 C content of a-C films through EELS analysis in the TEM
Galvan, D.; Pei, Y. T.; Hosson, J. Th. M. De; Cavaleiro, A.Electron energy loss spectroscopy (EELS) in a transmission electron microscope (TEM) was employed to estimate the sp3 C content in magnetron sputtered H-free a-C coatings. The deconvolution procedure developed reduces considerably the error which is due to beam point spread function and sample thickness. The methodology has been applied to thin a-C films deposited through RF magnetron sputtering, and determined...
Nanostructured TiC/a-C coatings for low friction and wear resistant applications
Pei, Y. T.; Galvan, D.; Hosson, J. Th. M. De; Cavaleiro, A.Closed-field unbalanced and balanced magnetron sputtering was used to deposit nanocrystalline TiC (nc-TiC)/amorphous carbon (a-C) nanocomposite coatings with hydrogenated or hydrogen-free a-C matrix, respectively. The contents of Ti and C in the coatings have been varied over the full range of interest (7-45 at.% Ti) by changing the flow rate of acetylene gas or the locations of substrates relative to the cente...
On the microstructure of tungsten disulfide films alloyed with carbon and nitrogen
Nossa, A.; Cavaleiro, A.; Carvalho, N. J. M.; Kooi, B. J.; Hosson, J. Th. M. DeThis work aimed at studying the effect of a Ti interlayer and the alloying with carbon and nitrogen of W-S-C(N) films on the mechanical and tribological properties. The W-S-C and W-S-N films were deposited by r.f. magnetron reactive sputtering with CH4 or N2 as reactive gases and analysed by high resolution electron microscopy techniques. The hardness showed an improvement with the addition of the alloying elem...
Microstructure, mechanical properties and cutting performance of superhard (Ti,...
Carvalho, S.; Ribeiro, E.; Rebouta, L.; Tavares, C.; Mendonça, J. P.; Monteiro, A. Caetano; Carvalho, N. J. M.; Hosson, J. Th. M. De; Cavaleiro, A.This paper reports on the optimization of coating properties to improve the performance of tools in severe cutting conditions. Tungsten carbide tools coated with (Ti,Si,Al)N films deposited by d.c. reactive magnetron sputtering have been investigated. The structure and the hardness of the coated samples were analyzed by X-ray diffraction (XRD) and depth-sensing indentation, respectively. XRD results revealed a ...
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