Nano-Thick Amorphous Oxide Layer Produced by Plasma on Type 316L Stainless Steel for Improved Corrosion Resistance Under Plastic Deformation

CORROSION ◽  
10.5006/2674 ◽  
2018 ◽  
Vol 74 (9) ◽  
pp. 1011-1022 ◽  
Author(s):  
Megan Mahrokh Dorri ◽  
Stéphane Turgeon ◽  
Maxime Cloutier ◽  
Pascale Chevallier ◽  
Diego Mantovani
Keyword(s):  
Plastic Deformation ◽  
Stainless Steel ◽  
Oxide Layer ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Localized Corrosion ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Amorphous Oxide ◽  
Amorphous Oxide Layer

Localized corrosion constitutes a major concern in medical devices made of stainless steel. The conventional approach to circumvent such a problem is to convert the surface polycrystalline microstructure of the native oxide layer to an amorphous oxide layer, a few micrometers thick. This process cannot, however, be used for devices such as stents that undergo plastic deformation during their implantation, especially those used in vascular surgery for the treatment of cardiac, neurological, and peripheral vessels. This work explores the feasibility of producing a nano-thick plastic-deformation resistant amorphous oxide layer by plasma-based surface modifications. By varying the plasma process parameters, oxide layers with different features were produced and their properties were investigated before and after clinically-relevant plastic deformation. These properties and the related corrosion mechanisms were mainly evaluated using the electrochemical methods of open-circuit potential, cyclic potentiodynamic polarization, and electrochemical impedance spectroscopy. Results showed that, under optimal conditions, the resistance to corrosion and to the permeation of ions in a phosphate buffered saline, even after deformation, was significantly enhanced.

On the Interface between Plasma Fluorocarbon Films and 316L Stainless Steel Substrates for Advanced Coated Stents

2011 ◽  
Vol 409 ◽  
pp. 117-122 ◽  
Author(s):  
Maxime Cloutier ◽  
Stéphane Turgeon ◽  
P. Chevallier ◽  
D. Mantovani
Keyword(s):  
Stainless Steel ◽  
Oxide Layer ◽  
Photoelectron Spectroscopy ◽  
Corrosion Behaviour ◽  
Drug Carrier ◽  
Native Oxide ◽  
Interfacial Region ◽  
Native Oxide Layer ◽  
Corrosion Performance ◽  
Stent Restenosis

As intravascular biomedical devices, metallic stents are particularly susceptible to corrosion induced by the physiological environment, causing the degradation of mechanical properties and leading to the release of toxic and carcinogenic ions from the SS316L bulk. Therefore, several works have been focused on the development of an ultra-thin fluorocarbon coating that could act both as a drug-carrier for in-stent restenosis and as an anti-corrosion barrier. However, the increase of the corrosion performance was limited by the inevitable permeability of the coating, which exposed some of the sensitive interfacial region to the corrosive environment. Indeed, in previous works, adhesion and growth rate of the film were promoted by the removal of the native oxide layer of the stainless steel which is inhomogeneous, brittle and mechanically unstable. Further refinements of the interface are therefore required in order to enhance the overall corrosion performance without compromising the fluorocarbon film properties and adhesion. Hence, the aim of this work was to enhance the corrosion behaviour of coated SS316L by the creation of a controlled interfacial oxide layer. The native oxide layer was first removed under vacuum and the bare metal surface was subjected to a plasma-reoxidation treatment. Tafel measurements were used to assess the corrosion rates of the specimens. Coated and uncoated modified interfaces were also characterized by X-Ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM).

scholarly journals Effect of Nitrogen on the Corrosion Behavior of Austenitic Stainless Steel in Chloride Solutions

2015 ◽  
Vol 9 (11) ◽  
pp. 119 ◽  
Author(s):  
W. A. Ghanem ◽  
W. A. Hussein ◽  
S. N. Saeed ◽  
S. M. Bader ◽  
R. M. Abou Shahba
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Localized Corrosion ◽  
Partial Replacement ◽  
General Corrosion ◽  
Heat Treated ◽  
The Difference

The effect of partial replacement of nickel with nitrogen on the corrosion resistance of newly designed austenitic stainless steel samples without and with heat treated was investigated in 3.5wt% and 5wt% NaCl solution using open-circuit, potentiodynamic, cyclic anodic polarization and electrochemical impedance spectroscopy techniques. The results showed that, passivation in sample 1 where the highest addition of nickel and low addition of nitrogen is different from that for sample 4 where the nitrogen is greatest and the nickel is reduced almost to the third comparing sample 1. The difference in responses of heat treated samples to localized and general corrosion could be attributed to the difference in their phase compositions. The appearance of ferrite phase for samples (2, 4, 5 and 6) after heat treatment resulted in lowering the general and localized corrosion resistance than as forged samples in contrast with samples 1 and 3, where they still pure austenite. The obtained results are confirmed by surface examination.

Improved GaAs metal-oxide semiconductor solar cells with a spin-on oxide layer

1981 ◽  
Vol 59 (5) ◽  
pp. 716-717
Author(s):  
P. Sircar ◽  
R. Dat
Keyword(s):  
Oxide Layer ◽  
Open Circuit Voltage ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Relative Increase ◽  
Open Circuit ◽  
Oxide Semiconductor ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Cell Efficiency

A thin native oxide layer grown on GaAs is known to increase the Schottky barrier solar cell efficiency by 60% over a baseline cell, due mainly to a higher open-circuit voltage. A physically-deposited oxide layer shows better efficiency and stability. A spin-on oxide layer is found to cause a higher relative increase in efficiency due to an increase in open-circuit voltage, as well as in short-circuit current.

Wettability in pressure infiltration of SiC and oxidized SiC particle compacts by molten Al and Al-12wt%Si alloy

2007 ◽  
Vol 22 (8) ◽  
pp. 2273-2278 ◽  
Author(s):  
J.M. Molina ◽  
J. Tian ◽  
C. Garcia-Cordovilla ◽  
E. Louis ◽  
J. Narciso
Keyword(s):  
Contact Angle ◽  
Oxide Layer ◽  
Low Temperatures ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Threshold Pressure ◽  
Pressure Infiltration ◽  
Surface Conditions ◽  
Infiltration Behavior ◽  
Sic Particle

The infiltration behavior of compacts of SiC particles in two surface conditions, as-received and thermally oxidized, was investigated by using pure Al and Al-12wt%Si as infiltrating metals. Analysis of the threshold pressure for infiltration revealed that the process is governed by the same contact angle for all different systems, no matter the metal or particle condition. This leads to the conclusion that oxidation does not modify the wetting characteristics of the particles, most probably because they are already covered by a thin native oxide layer that remains unaltered in processing routes involving short contact times and low temperatures, such as actual conditions of pressure infiltration at 700 °C.

scholarly journals From Waste to Valuable Resource: Lignin as a Sustainable Anti-Corrosion Coating

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 454 ◽  
Author(s):  
Arman Dastpak ◽  
Kirsi Yliniemi ◽  
Mariana de Oliveira Monteiro ◽  
Sarah Höhn ◽  
Sannakaisa Virtanen ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Steel Corrosion ◽  
Linear Sweep Voltammetry ◽  
Corrosion Current ◽  
Polymer Coatings ◽  
Open Circuit ◽  
Linear Sweep ◽  
Cyclic Potentiodynamic Polarization

In this study, a waste of biorefinery—lignin—is investigated as an anticorrosion coating on stainless steel. Corrosion behavior of two lignin types (hardwood beech and softwood spruce) was studied by electrochemical measurements (linear sweep voltammetry, open circuit potential, potentiostatic polarization, cyclic potentiodynamic polarization, and electrochemical impedance measurements) during exposure to simulated body fluid (SBF) or phosphate buffer (PBS). Results from linear sweep voltammetry of lignin-coated samples, in particular, demonstrated a reduction in corrosion current density between 1 and 3 orders of magnitude cf. blank stainless steel. Furthermore, results from cross cut adhesion tests on lignin-coated samples demonstrated that the best possible adhesion (grade 0) of ISO 2409 standard was achieved for the investigated novel coatings. Such findings suggest that lignin materials could transform the field of organic coatings towards more sustainable alternatives by replacing non-renewable polymer coatings.

The Effect of Surface States on Secondary Electron (SE) Dopant Contrast from Silicon p-n Junctions

2007 ◽  
Vol 1026 ◽  
Author(s):  
Augustus K. W. Chee ◽  
Conny Rodenburg ◽  
Colin John Humphreys
Keyword(s):  
Oxide Layer ◽  
Computer Modelling ◽  
Surface States ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Element Analysis ◽  
Surface Band ◽  
Band Bending ◽  
Wide Range ◽  
Se Doping

AbstractDetailed computer modelling using finite-element analysis was performed for Si p-n junctions to investigate the effects of surface states and doping concentrations on surface band-bending, surface junction potentials and external patch fields. The density of surface states was determined for our Si specimens with a native oxide layer. Our calculations show that for a typical density of surface states for a Si specimen with a native oxide layer, the effects of external patch fields are negligible and the SE doping contrast is due to the built-in voltage across the p-n junction modified by surface band-bending. There is a good agreement between the experimental doping contrast and the calculated junction potential just below the surface, taking into account surface states, for a wide range of doping concentrations.

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