Long-Term Stable H2 Production from Methylcyclohexane Using a Membrane Reactor with a Dimethoxydiphenylsilane-Derived Silica Membrane Prepared via Chemical Vapor Deposition

Amorphous siliconlike films with hydrophobic functionalities have been deposited by plasma-enhanced chemical-vapor deposition on carbon-fiber-reinforced polymer (CFRP) unidirectional laminates used for micromechanical applications where high strength-to-weight and high stiffness-to-weight ratios are required. To improve long-term geometrical stability in ultrahigh-precision machine structures, hydrophobic CFRP materials are desirable. Three layers have been grown with different plasma-process parameters from a mixture of hexamethyldisiloxane, O2, and Ar. Chemical composition, water contact angle, surface energy, morphology, and tribological properties have been evaluated to choose the one that best fulfills hydrophobicity, wear, and scratch resistance. Wear tests have also been carried out on CFRP laminates coated with a polyurethane layer to compare the wear performance of the above specimens with that of a conventional hydrophobic coating. Scanning electron microscope images show a very good adhesion of the films to the composite substrate because the failure of the film and of the substrate (such as fiber failure) take place simultaneously.

Download Full-text

Long-term stable water vapor permeation barrier properties of SiN/SiCN/SiN nanolaminated multilayers grown by plasma-enhanced chemical vapor deposition at extremely low pressures

Applied Physics Letters ◽

10.1063/1.4892354 ◽

2014 ◽

Vol 105 (5) ◽

pp. 053302 ◽

Cited By ~ 3

Author(s):

Bum Ho Choi ◽

Jong Ho Lee

Keyword(s):

Chemical Vapor Deposition ◽

Water Vapor ◽

Vapor Deposition ◽

Chemical Vapor ◽

Barrier Properties ◽

Vapor Permeation ◽

Low Pressures ◽

Water Vapor Permeation

Download Full-text

Chemical Vapor Deposition of N-Doped Graphene through Pre-Implantation of Nitrogen Ions for Long-Term Protection of Copper

Materials ◽

10.3390/ma14133751 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3751

Author(s):

Luoqiao Han ◽

Lei Dong ◽

Haiyan Chen ◽

Shuai Yang ◽

Aiheng Yuan ◽

...

Keyword(s):

Corrosion Resistance ◽

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Galvanic Corrosion ◽

Chemical Vapor ◽

Pristine Graphene ◽

Ambient Exposure ◽

N Doping ◽

Doped Graphene

Nitrogen-doped graphene (NG) was synthesized through the chemical vapor deposition (CVD) of graphene on Cu substrates, which were pre-implanted with N ions by the ion implantation method. The pre-implanted N ions in the Cu substrate could dope graphene by the substitution of C atoms during the CVD growth of graphene, forming NG. Based on this, NG’s long-term protection properties for Cu were evaluated by ambient exposure for a corrosion test. The results showed that NG can obviously reduce the natural oxidation of Cu in the long-term exposure compared with the case of pristine graphene (PG) coated on Cu. Moreover, with the increase in pre-implanted N dose, the formed NG’s long-term protection for Cu improved. This indicates that the modification of graphene by N doping is an effective way to improve the corrosion resistance of the PG coating owing to the reduction in its conductivity, which would inhibit galvanic corrosion by cutting off electron transport across the interface in their long-term protection. These findings provide insight into corrosion mechanisms of the graphene coating and correlate with its conductive nature based on heteroatoms doping, which is a potential route for improving the corrosion resistance of graphene as an effective barrier coating for metals.

Download Full-text

Silicon Field Emission Arrays Coated with CoSi2 Layer Grown by Reactive Chemical Vapor Deposition

MRS Proceedings ◽

10.1557/proc-621-r5.1.1 ◽

2000 ◽

Vol 621 ◽

Author(s):

Byung Wook Han ◽

Hwa Sung Rhee ◽

Byung Tae Ahn ◽

Nam Yang Lee

Keyword(s):

Chemical Vapor Deposition ◽

Field Emission ◽

Vapor Deposition ◽

Chemical Vapor ◽

Emission Current ◽

Emission Properties ◽

Long Term Stability ◽

Field Emission Arrays

ABSTRACTWe prepared Si emitters coated with an MOCVD CoSi2 layer to improve the emission properties. The CoSi2 layer was grown in situ by reactive chemical vapor deposition of cyclopentadienyl dicarbonyl cobalt at 650 °C. The CoSi2 layer was conformally coated on the Si emitter tips and had a twinned structure at the epitaxial CoSi2/Si interface. The CoSi2-coated Si emitters showed an enhanced emission due to the increase of the number of emitting site from Fowler-Nordheim plot. The fluctuation of emission current was reduced by CoSi2 coating. But the long-term stability was not much improved.

Download Full-text