scholarly journals Effect of Molybdenum Content on Mechanical and Tribological Properties of Diamond-Like Carbon Coatings over Titanium β-21S Alloy

2020 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Dilli Babu Padmanaban ◽  
Loganathan Mohan ◽  
Preetam Giri ◽  
Parthasarathi Bera ◽  
Chinnasamy Anandan ◽  
...  

Molybdenum-doped diamond-like carbon (Mo-DLC) coatings have been deposited on titanium β-21S alloy (Ti–15Mo–3Nb–3Al–0.2Si) using plasma-enhanced chemical vapor deposition (PECVD) equipped with pulsed-DC magnetron sputtering. Mo contents in the deposited coatings have been controlled with an applied sputtering pulse duty cycle. Chemical composition, structure, morphology, and topography have been studied using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM), respectively. XRD pattern of the coating with highest Mo content shows the presence of carbide phase. Smooth features with low roughness values are observed in low Mo content coating, whereas high Mo content coating shows granular characteristics with a high roughness value. Raman spectra reveal the increased graphitic content for the highest metal concentration in the coatings, wherein the nanohardness is also determined to be highest, at about ~18–19 GPa. Furthermore, the ball-on-disk tribometry test on Mo-DLC coating with highest nanohardness shows a low coefficient of friction (COF) of 0.2 with low wear loss compared to that of the substrate (0.62).

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3543
Author(s):  
Parand R. Riley ◽  
Pratik Joshi ◽  
Sina Azizi Machekposhti ◽  
Ritesh Sachan ◽  
Jagdish Narayan ◽  
...  

In this study, we describe reducing the moisture vapor transmission through a commercial polymer bag material using a silicon-incorporated diamond-like carbon (Si-DLC) coating that was deposited using plasma-enhanced chemical vapor deposition. The structure of the Si-DLC coating was analyzed using scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, selective area electron diffraction, and electron energy loss spectroscopy. Moisture vapor transmission rate (MVTR) testing was used to understand the moisture transmission barrier properties of Si-DLC-coated polymer bag material; the MVTR values decreased from 10.10 g/m2 24 h for the as-received polymer bag material to 6.31 g/m2 24 h for the Si-DLC-coated polymer bag material. Water stability tests were conducted to understand the resistance of the Si-DLC coatings toward moisture; the results confirmed the stability of Si-DLC coatings in contact with water up to 100 °C for 4 h. A peel-off adhesion test using scotch tape indicated that the good adhesion of the Si-DLC film to the substrate was preserved in contact with water up to 100 °C for 4 h.


2012 ◽  
Vol 706-709 ◽  
pp. 2596-2601
Author(s):  
E. Vogli ◽  
Fabian Hoffmann ◽  
E. Bartis ◽  
G. S. Oehrlein ◽  
Wolfgang Tillmann

It has been established that hardness and density of diamond-like carbon (DLC) layers can be raised by increasing ion energy during deposition, decreasing H-content and by increasing sp3-fraction. To confirm differences in hydrogen content of hydrogen containing and hydrogen free DLC films deposited at different bias voltages, layers were etched in oxygen atmosphere in a capacitively coupled plasma device. By employing real-time ellipsometry measurements, the H-content of the hydrogen containing a-C:H layers were estimated by determining the optical constants n and k (n-real part and k-imaginary part of the refractive index). In addition, DLC layers were analyzed by X-ray photoelectron spectroscopy to estimate the ratio of sp²- and sp³-hybridization. The mechanical and tribological properties of the coatings were evaluated by means of nanoindentation and ball-on-disc-tests. Finally correlations between these properties, H-content and sp3/sp2-ratio were obtained in an effort to explain different tribological behaviors of DLC-layers.


Author(s):  
Nicholaos G. Demas ◽  
Andreas A. Polycarpou ◽  
Kyriaki Polychronopoulou ◽  
Claus Rebholz

The tribological behavior of CrN and Al-Cr-N coatings prepared by twin electron-beam evaporation at 450°C was investigated. The composition, structure, mechanical and tribological properties of the coatings were determined using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) in combination with nanoindentation mechanical property measurements, scanning electron microscopy (SEM), and laboratory controlled ball-on-disc sliding experiments. It was found that all of the Al-Cr-N coatings exhibit higher hardness compared to CrN coatings. Also, the compositions of Al-Cr-N coatings with the lower Al content and lower Al/Cr ratios showed better tribological performance than the rest of the coatings.


Coatings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 370 ◽  
Author(s):  
Imane Bouabibsa ◽  
Salim Lamri ◽  
Frederic Sanchette

Metal containing hydrogenated diamond-like carbon coatings (Me-DLC, Me = Al, Ti, or Nb) of 3 ± 0.2 μm thickness were deposited by a magnetron sputtering-RFPECVD hybrid process in an Ar/H2/C2H2 mixture. The composition and structure were investigated by Energy Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The residual stress was measured using the curvature method and nanoindentation was used to determine the hardness and the Young’s modulus. A Ball-on-disk tribometer was employed to investigate the frictional properties and sliding wear resistance of films. The results show that the properties depend on the nature and the Me content in the coatings. The doping of the DLC coatings leads to a decrease in hardness, Young’s modulus, and residual stresses. Wear rate of the films first decreases with intermediate Me contents and then increases for higher Me contents. Significant improvements in the friction coefficient on steel as well as in the wear rate are observed for all Al-DLC coatings, and, concerning the friction coefficient, the lowest value is measured at 0.04 as compared to 0.07 for the undoped DLC.


2005 ◽  
Vol 879 ◽  
Author(s):  
Scott K. Stanley ◽  
John G. Ekerdt

AbstractGe is deposited on HfO2 surfaces by chemical vapor deposition (CVD) with GeH4. 0.7-1.0 ML GeHx (x = 0-3) is deposited by thermally cracking GeH4 on a hot tungsten filament. Ge oxidation and bonding are studied at 300-1000 K with X-ray photoelectron spectroscopy (XPS). Ge, GeH, GeO, and GeO2 desorption are measured with temperature programmed desorption (TPD) at 400-1000 K. Ge initially reacts with the dielectric forming an oxide layer followed by Ge deposition and formation of nanocrystals in CVD at 870 K. 0.7-1.0 ML GeHx deposited by cracking rapidly forms a contacting oxide layer on HfO2 that is stable from 300-800 K. Ge is fully removed from the HfO2 surface after annealing to 1000 K. These results help explain the stability of Ge nanocrystals in contact with HfO2.


1999 ◽  
Vol 567 ◽  
Author(s):  
Renee Nieh ◽  
Wen-Jie Qi ◽  
Yongjoo Jeon ◽  
Byoung Hun Lee ◽  
Aaron Lucas ◽  
...  

ABSTRACTBa0.5Sr0.5TiO3 (BST) is one of the high-k candidates for replacing SiO2 as the gate dielectric in future generation devices. The biggest obstacle to scaling the equivalent oxide thickness (EOT) of BST is an interfacial layer, SixOy, which forms between BST and Si. Nitrogen (N2) implantation into the Si substrate has been proposed to reduce the growth of this interfacial layer. In this study, capacitors (Pt/BST/Si) were fabricated by depositing thin BST films (50Å) onto N2 implanted Si in order to evaluate the effects of implant dose and annealing conditions on EOT. It was found that N2 implantation reduced the EOT of RF magnetron sputtered and Metal Oxide Chemical Vapor Deposition (MOCVD) BST films by ∼20% and ∼33%, respectively. For sputtered BST, an implant dose of 1×1014cm−;2 provided sufficient nitrogen concentration without residual implant damage after annealing. X-ray photoelectron spectroscopy data confirmed that the reduction in EOT is due to a reduction in the interfacial layer growth. X-ray diffraction spectra revealed typical polycrystalline structure with (111) and (200) preferential orientations for both films. Leakage for these 50Å BST films is on the order of 10−8 to 10−5 A/cm2—lower than oxynitrides with comparable EOTs.


Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 510
Author(s):  
Yongqiang Pan ◽  
Huan Liu ◽  
Zhuoman Wang ◽  
Jinmei Jia ◽  
Jijie Zhao

SiO2 thin films are deposited by radio frequency (RF) plasma-enhanced chemical vapor deposition (PECVD) technique using SiH4 and N2O as precursor gases. The stoichiometry of SiO2 thin films is determined by the X-ray photoelectron spectroscopy (XPS), and the optical constant n and k are obtained by using variable angle spectroscopic ellipsometer (VASE) in the spectral range 380–1600 nm. The refractive index and extinction coefficient of the deposited SiO2 thin films at 500 nm are 1.464 and 0.0069, respectively. The deposition rate of SiO2 thin films is controlled by changing the reaction pressure. The effects of deposition rate, film thickness, and microstructure size on the conformality of SiO2 thin films are studied. The conformality of SiO2 thin films increases from 0.68 to 0.91, with the increase of deposition rate of the SiO2 thin film from 20.84 to 41.92 nm/min. The conformality of SiO2 thin films decreases with the increase of film thickness, and the higher the step height, the smaller the conformality of SiO2 thin films.


Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 787
Author(s):  
Weiqi Wang ◽  
Xiaoming Ling ◽  
Rui Wang ◽  
Wenhao Nie ◽  
Li Ji ◽  
...  

The spontaneously self-organizing multilayered graphite-like carbon (denoted as GLC) /TiC films with various bilayer periods in the range of 13.3–17.5 nm were deposited on silicon and 1Cr18Mn8Ni5N stainless steel substrates using closed field magnetron sputtering deposition facility. The microstructures and chemical compositions of the prepared multilayered films were characterized by scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy respectively. The self-organizing multilayered structures in all of the films consisted of titanium carbide layers and sp2-rich carbon layers periodically alternate arrangement. The TiC contents and bilayer periods of the multilayered films can be controlled by means of adjusting of sputtering current of graphite target. Furthermore, the mechanical and tribological performances of the prepared films were appraised by nano-indentor, scratch measures, and ball-on-plate tribometer respectively. The results indicated that multilayer structure endowed the as-deposited TiC/GLC films outstanding mechanical and tribological properties, especially the multilayer film with 15.9 nm bilayer period deposited at 10 A sputtering current showed the excellent adhesion strength and hardness; Simultaneously it also exhibited the lowest average friction coefficient in the humid environment owing to its high content of sp2 hybrid carbon.


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