scholarly journals Development of Microstructured Carbon Coatings by Substrate-Catalytic CVD

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1403
Author(s):  
Mattia Pierpaoli ◽  
Mirosław Sawczak ◽  
Anna Dettlaff
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Electrochemical Behavior ◽  
Chemical Vapor ◽  
Synthesis Temperature ◽  
Carbon Films ◽  
Nanostructured Carbon ◽  
Moderate Amount ◽  
Carbon Coatings ◽  
Chromium Oxide Layer

Carbon nanostructured films were synthesized by chemical vapor deposition (CVD) on H18 stainless steel (AISI 440C) sheets with an H2/CH4/N2 gas mixture at various substrate temperatures. During the synthesis, the iron and chromium oxide layer was formed between the steel and carbonaceous layer. The carbon films exhibited wall-like and spherical morphologies and structures, as characterized by scanning electron microscopy and Raman spectroscopy. It was found that the synthesis temperature affects the microsphere density and, therefore, also in the electrochemical behavior. The electrochemical behavior of nanostructured carbon coatings strongly depends on the CVD deposition conditions. The best corrosion resistance (Rp = 11.8 MΩ·cm2, Icorr = 4.4 nA·cm−2) exhibits a nanostructured carbon sample with a moderate amount of sp2-C-rich carbon microspheres CμSs synthesized at 700 °C. The corrosion resistance of the nanostructured carbon coating is better than raw stainless steel.

Investigation of diffusion alloying time on electrochemical behavior and conductivity of Nb-modified AISI 430 SS as PEMFC bipolar plate

2019 ◽  
Vol 66 (4) ◽  
pp. 520-526
Author(s):  
Fupeng Cheng ◽  
Jinglong Cui ◽  
Shuai Xu ◽  
Hongyu Wang ◽  
Pengchao Zhang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Electrochemical Behavior ◽  
Surface Conductivity ◽  
Proton Exchange ◽  
Corrosion Mechanism ◽  
Content Type ◽  
Surface Electrical Conductivity ◽  
Aisi 430

Purpose The purpose of this paper is to improve the surface electrical conductivity and corrosion resistance of AISI 430 stainless steel (430 SS) as bipolar plates for proton exchange membrane fuel cells (PEMFCs), a protective Nb-modified layer is formed onto stainless steel via the plasma surface diffusion alloying method. The effect of diffusion alloying time on electrochemical behavior and surface conductivity is evaluated. Design/methodology/approach In this work, the surface electrical conductivity and corrosion resistance of modified specimen are evaluated by the potentiodynamic and potentionstatic polarization tests. Moreover, the hydrophobicity is also investigated by contact angle measurement. Findings The Nb-modified 430 SS treated by 1.5 h (1.5Nb) presented a lower passivation current density, lower interfacial contact resistance and a higher hydrophobicity than other modified specimens. Moreover, the 1.5 Nb specimen presents a smoother surface than other modified specimens after potentionstatic polarization tests. Originality/value The effect of diffusion alloying time on electrochemical behavior, surface conductivity and hydrophobicity of modified specimen is evaluated. The probable anti-corrosion mechanism of Nb-modified specimen in simulated acid PEMFC cathode environment is presented.

Thermally stimulated exoelectron emission from hydrogenated amorphous carbon films

1992 ◽  
Vol 7 (7) ◽  
pp. 1805-1808
Author(s):  
Yoshihisa Watanabe ◽  
Yoshikazu Nakamura ◽  
Shigekazu Hirayama ◽  
Yoshimasa Yamaguchi
Keyword(s):  
Stainless Steel ◽  
Amorphous Carbon ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Rf Plasma ◽  
Exoelectron Emission ◽  
Hydrogenated Amorphous Carbon ◽  
Hydrogenated Amorphous

Hydrogenated amorphous carbon (a–C:H) films on stainless steel (AISI430) substrate oxidized in air at 1273 K were prepared from a gas mixture of methane and hydrogen by an rf plasma chemical vapor deposition, and thermally stimulated exoelectron emission (TSEE) was studied for the x-ray irradiated a–C:H films. Glow curves and energy distributions of TSEE from the 80- and 280-nm a–C:H films and from the AISI430 substrate have been measured under ultrahigh vacuum conditions. It was found that the glow curve from the 80-nm a–C:H film was similar to that from the AISI430 substrate, but it was quite different from that from the 280-nm film; the values of the mean energy of exoelectrons at the glow peak temperatures from the 80-nm a–C:H film are almost the same as those from the substrate but are much lower than those of the 280-nm film. The surfaces of 80- and 280-nm a–C:H films are observed with the scanning electron microscope (SEM). Observations by SEM show that the 80-nm film has relatively large-sized clusters of films and the stainless steel substrate still appears in some places, but the surface of the 280-nm film is completely covered by the carbon films. From these results, we propose that TSEE from the 80-nm film originates mainly from the oxide films on the stainless steel substrate and TSEE from the 280-nm film originates from the film itself. Thus, TSEE can be applied to characterize the surface of thin films.

scholarly journals Effect of C/Si Ratio on the Electrochemical Behavior of a-SiCx:H Coatings on SS301 Substrate Deposited by PECVD

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
D. Li ◽  
S. Guruvenket ◽  
J. A. Szpunar ◽  
J. E. Klemberg-Sapieha
Keyword(s):  
Stainless Steel ◽  
Electrochemical Behavior ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Corrosion Current ◽  
Amorphous Structure ◽  
Hydrogenated Silicon ◽  
Amorphous Hydrogenated Silicon ◽  
Afm Analysis

Amorphous hydrogenated silicon carbide (a-SiCx:H) coatings were deposited on stainless steel 301 (SS301) using plasma enhanced chemical vapor deposition with the methane gas flow ranging from 30 to 90 sccm. XRD spectra confirmed the amorphous structure of these coatings. The as-deposited coatings all exhibited homogenous dense feature, and no porosities were observed in SEM and AFM analysis. The a-SiCx:H coatings remarkably increased the corrosion resistance of the SS301 substrate. With the increase of the C concentration, the a-SiCx:H coatings exhibited significantly enhanced electrochemical behavior. The a-SiCx:H coating with the highest carbon concentration acted as an excellent barrier to charge transfer, with a corrosion current of3.5×10-12 A/cm2and a breakdown voltage of 1.36 V, compared to2.5×10-8 A/cm2and 0.34 V for the SS301 substrate.

Preliminary Study: Direct Growth Carbon Nanomaterials on Metal Substrate to Improve Corrosion Resistance

2015 ◽  
Vol 819 ◽  
pp. 81-86
Author(s):  
A.N. Edzatty ◽  
A.H. Norzilah ◽  
Shamsul Baharin Jamaludin
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Carbon Nanomaterials ◽  
Chemical Vapor ◽  
Metal Substrate ◽  
X Ray ◽  
Specific Strength ◽  
Direct Growth ◽  
Size And Morphology ◽  
Stainless Steel 316

Metals are increasingly used in engineering due to their high specific strength. However, some of pure metals do not posses good corrosion resistance. Therefore carbon nanomaterials (CNMs) has been studied to overwhelm the corrosion existed on the metal’s surface. CNMs are synthesized directly on various metal substrates by Chemical Vapor Deposition (CVD) technique without addition of any external catalyst, in reactor at temperature of 800°C. Argon with a flow rate of 200ml/min was used as a carrier gas and acetone as a carbon source. In this study, two different metals were used as metal substrate: mild steel and stainless steel 316. The morphology, existence of CNTs and elemental analysis of the CNMs on metal substrate are evaluated using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Energy Dispersive X-ray (EDX), respectively. It was proven that the different element composition of metal substrate influenced the size and morphology of CNMs. The most suitable metal to grow CNTs was found to be stainless steel.

Synthesis of Stainless Steel/CNTs Nanocomposite Powders

2010 ◽  
Vol 93-94 ◽  
pp. 181-184 ◽  
Author(s):  
Duanghathai Kaewsai ◽  
Pisith Singjai ◽  
Pannada Niranatlumpong ◽  
Anucha Watcharapasorn ◽  
Sukanda Jiansirisomboon
Keyword(s):  
Carbon Nanotubes ◽  
Stainless Steel ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Average Diameter ◽  
Synthesis Temperature ◽  
Synthesis Time ◽  
Cvd Method ◽  
Optimum Synthesis ◽  
Nanocomposite Powders

Stainless steel/carbon nanotubes (CNTs) nanocomposite powders were synthesized by chemical vapor deposition (CVD) method with ethanol as a carbon source. The effects of synthesis temperature and time on microstructure and chemical composition of the powders were investigated. The as-received stainless steel powders were synthesized at temperature in between 550-800°C for 30-180 min at a pressure of 10 Torr. The optimum synthesis condition was found to be 800°C for 120 min. Average diameter of CNTs grown on stainless steel particles slightly increased with increasing growth temperature. The synthesis time, however, was found to have no effect on the size of CNTs.

Increasing Surface Hardness of S304 Stainless Steel by High Quality Graphene Grown by Chemical Vapor Deposition

2020 ◽  
Vol 302 ◽  
pp. 79-84
Author(s):  
Piyaporn Surinlert ◽  
Akkawat Ruammaitree
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Chemical Vapor Deposition ◽  
Carbon Source ◽  
Vapor Deposition ◽  
Surface Hardness ◽  
Chemical Vapor ◽  
High Quality ◽  
Methane Gas ◽  
Intrinsic Strength

Stainless steel is widely utilized due to its higher corrosion resistance and gloss than ordinary steels. However, the applications of stainless steel are still limited because of its low surface hardness. Graphene is a superb material, which has an intrinsic strength of 130 GPa. In this report, the growth of high quality graphene on S304 stainless steel by chemical vapor deposition using acetylene gas as a carbon source is demonstrated. The surface hardness of stainless steel after growing high quality graphene is investigated by nanoindentation technique. High quality graphene can increase the surface hardness of stainless steel from 1.54 GPa to 10.08 GPa. Moreover, the effect of graphene quality on the surface hardness of S304 stainless steel is studied. High quality graphene grown by CVD using acetylene gas as a carbon source can increase the surface hardness of stainless steel about two times more than low quality graphene grown by using methane gas.

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