scholarly journals Raman Spectroscopy Characterization of amorphous carbon coatings for computer hard disks

1998 ◽  
Author(s):  
Joel W. Ager III
Keyword(s):  
Raman Spectroscopy ◽  
Amorphous Carbon ◽  
Hard Disks ◽  
Carbon Coatings ◽  
Amorphous Carbon Coatings

scholarly journals Amorphous Carbon Coatings for Total Knee Replacements—Part I: Deposition, Cytocompatibility, Chemical and Mechanical Properties

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1952
Author(s):  
Benedict Rothammer ◽  
Kevin Neusser ◽  
Max Marian ◽  
Marcel Bartz ◽  
Sebastian Krauß ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Amorphous Carbon ◽  
Detailed Characterization ◽  
Carbon Coatings ◽  
Dlc Coatings ◽  
Total Knee Replacements ◽  
Knee Replacements ◽  
Total Knee ◽  
Amorphous Carbon Coatings

Diamond-like carbon (DLC) coatings have the potential to reduce implant wear and thus to contribute to avoiding premature failure and increase service life of total knee replacements (TKAs). This two-part study addresses the development of such coatings for ultrahigh molecular weight polyethylene (UHMWPE) tibial inlays as well as cobalt–chromium–molybdenum (CoCr) and titanium (Ti64) alloy femoral components. While a detailed characterization of the tribological behavior is the subject of part II, part I focusses on the deposition of pure (a‑C:H) and tungsten-doped hydrogen-containing amorphous carbon coatings (a‑C:H:W) and the detailed characterization of their chemical, cytological, mechanical and adhesion behavior. The coatings are fabricated by physical vapor deposition (PVD) and display typical DLC morphology and composition, as verified by focused ion beam scanning electron microscopy and Raman spectroscopy. Their roughness is higher than that of the plain substrates. Initial screening with contact angle and surface tension as well as in vitro testing by indirect and direct application indicate favorable cytocompatibility. The DLC coatings feature excellent mechanical properties with a substantial enhancement of indentation hardness and elastic modulus ratios. The adhesion of the coatings as determined in modified scratch tests can be considered as sufficient for the use in TKAs.

scholarly journals Comparison of Carbon Thin Films with Low Secondary Electron Yield Deposited in Neon and Argon

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 884
Author(s):  
Yuxin Zhang ◽  
Yigang Wang ◽  
Sihui Wang ◽  
Wei Wei ◽  
Xiaoqin Ge ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Amorphous Carbon ◽  
Secondary Electron ◽  
High Energy ◽  
Carbon Coatings ◽  
Secondary Electron Yield ◽  
Electron Yield ◽  
Carbon Thin Films ◽  
Amorphous Carbon Coatings

Modification of vacuum chamber surface properties by introducing a layer of material with low secondary electron yield (SEY) is one of the most useful solutions to suppress the electron-cloud in high-energy particle accelerators. In the present work, amorphous carbon thin films have been produced by DC magnetron sputtering with Neon and Argon sputtering gases. Microstructures of the thin films have been characterized by using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The sp2 and sp3 hybridized carbon atoms are evaluated using X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The amorphous carbon coatings comprise tiny granularities of tens of nanometers. The amorphous carbon films show more graphite-like properties as revealed by XPS and Raman spectroscopy. The secondary electron emission measurement results indicate that amorphous carbon coatings present SEY of <1.2. The thin film deposited by Ne exhibits a higher sp2 hybridization content, leading to a slightly lower SEY compared with the film produced with Ar.

Micro/nanomechanical and tribological characterization of ultrathin amorphous carbon coatings

1999 ◽  
Vol 14 (6) ◽  
pp. 2328-2337 ◽  
Author(s):  
Xiaodong Li ◽  
Bharat Bhushan
Keyword(s):  
Wear Resistance ◽  
Amorphous Carbon ◽  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Carbon Coatings ◽  
Load Carrying ◽  
Tribological Characterization ◽  
Thick Coatings ◽  
Amorphous Carbon Coatings

Micro/nanomechanical and tribological characterization of ultrathin amorphous carbon coatings, deposited by filtered cathodic arc (FCA), direct ion beam (IB), electron cyclotron resonance plasma chemical vapor deposition (ECR-CVD), and sputter (SP) deposition processes on Si substrate have been conducted using a nanoindenter with a nanoscratch attachment and an accelerated ball-on-flat tribometer. Coating thicknesses of 20, 10, 5 nm and, for the first time, 3.5 nm coatings have been investigated. It was found the FCA coating exhibits the highest hardness and elastic modulus, followed by the ECR-CVD, IB, and SP coatings. In general, the thicker coatings exhibited better scratch/wear performance than the thinner coatings due to their better load-carrying capacity as compared to the thinner coatings. At 20 nm, the FCA and ECR-CVD coatings show the best scratch and wear resistance, while the IB and ECR-CVD coatings show the best scratch and wear resistance at 10 nm. Five nanometer thick coatings show reasonable scratch and wear resistance, while 3.5 nm thick coatings show extremely low load-carrying capacity and poor scratch and wear resistance. It appears that the 3.5 nm coatings studied are unfeasible for scratch and wear resistance applications as of now.

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