Influence of migration of iron particles, ions and compounds during long term marine immersion corrosion

2007 ◽  
Vol 42 (2) ◽  
pp. 145-151
Author(s):  
R. Jeffrey ◽  
R. E. Melchers
Keyword(s):  
Iron Particles ◽  
Immersion Corrosion

scholarly journals Solvent Dependence of the Rheological Properties in Hydrogel Magnetorheological Plastomer

2020 ◽  
Vol 21 (5) ◽  
pp. 1793 ◽  
Author(s):  
Norhiwani Mohd Hapipi ◽  
Saiful Amri Mazlan ◽  
U. Ubaidillah ◽  
Siti Aishah Abdul Aziz ◽  
Muntaz Hana Ahmad Khairi ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Binary Mixtures ◽  
Binary Solvent ◽  
Iron Particles ◽  
Magnetic Performance ◽  
Solvent Dependence ◽  
Mr Effect ◽  
External Stimuli ◽  
Pva Hydrogel

Chemically crosslinked hydrogel magnetorheological (MR) plastomer (MRP) embedded with carbonyl iron particles (CIPs) exhibits excellent magnetic performance (MR effect) in the presence of external stimuli especially magnetic field. However, oxidation and desiccation in hydrogel MRP due to a large amount of water content as a dispersing phase would limit its usage for long-term applications, especially in industrial engineering. In this study, different solvents such as dimethyl sulfoxide (DMSO) are also used to prepare polyvinyl alcohol (PVA) hydrogel MRP. Thus, to understand the dynamic viscoelastic properties of hydrogel MRP, three different samples with different solvents: water, DMSO, and their binary mixtures (DMSO/water) were prepared and systematically carried out using the oscillatory shear. The outcomes demonstrate that the PVA hydrogel MRP prepared from precursor gel with water shows the highest MR effect of 15,544% among the PVA hydrogel MRPs. However, the samples exhibit less stability and tend to oxidise after a month. Meanwhile, the samples with binary mixtures (DMSO/water) show an acceptable MR effect of 11,024% with good stability and no CIPs oxidation. Otherwise, the sample with DMSO has the lowest MR effect of 7049% and less stable compared to the binary solvent samples. This confirms that the utilisation of DMSO as a new solvent affects the rheological properties and stability of the samples.

scholarly journals Material Characterization of Magnetorheological Elastomers with Corroded Carbonyl Iron Particles: Morphological Images and Field-dependent Viscoelastic Properties

2019 ◽  
Vol 20 (13) ◽  
pp. 3311 ◽  
Author(s):  
Siti Aishah Binti Abdul Aziz ◽  
Saiful Amri Mazlan ◽  
Nur Azmah Nordin ◽  
Nor Azlin Nazira Abd Rahman ◽  
U Ubaidillah ◽  
...  
Keyword(s):  
Carbonyl Iron ◽  
Matrix Material ◽  
Rheological Characteristics ◽  
Iron Particles ◽  
Ambient Conditions ◽  
X Ray ◽  
Field Dependent ◽  
Mr Effect

High temperatures and humidity could alter the field-dependent rheological properties of MR materials. These environmental phenomena may accelerate the deterioration processes that will affect the long-term rheological reliability of MR materials such as MR elastomer (MRE). This study therefore attempts to investigate the field-dependent rheological characteristics of MRE with corroded carbonyl iron particles (CIPs). The corroded CIPs were treated with hydrochloric acid (HCl) as a way of providing realistic environments in gauging the CIPs reaction towards the ambient conditions. The corroded CIPs along with silicone rubber as a matrix material were used in the fabrication of the MRE samples. To observe the effect of HCl treatment on the CIPs, the morphological observations of MREs with non-corroded and corroded CIPs were investigated via field emission scanning electron microscopy (FESEM), energy-dispersive x-ray spectroscopy (EDX) and x-ray diffractometer (XRD). In addition, the magnetic properties were examined through the vibrating sample magnetometer (VSM), while the field-dependent rheological characteristics such as the storage modulus of MRE with the corroded CIPs were also tested and compared with the non-corroded CIPs. The results showed that the corroded CIPs possessed hydrangea-like structures. In the meantime, it was identified that a sudden reduction of up to 114% of the field-dependent MR effect of MRE with the corroded CIPs was observed as a result of the weakened interfacial bonding between the CIPs and the silicon in the outer layers of the CIPs structure.

Long-term immersion corrosion of irons and steel in seawaters with calcareous deposition

CORROSION ◽  
10.5006/3685 ◽  
2021 ◽  
Author(s):  
Robert Melchers
Keyword(s):  
Direct Evidence ◽  
Low Permeability ◽  
Microbiological Corrosion ◽  
Wrought Iron ◽  
Corrosion Rates ◽  
Immersion Corrosion ◽  
Moderate Power ◽  
Power Law Function ◽  
Ferrous Carbonate

The marine immersion corrosion of irons and steel under calcareous deposition (principally calcium carbonate) is known to be relatively low for shorter exposures (e.g. a few years). Herein the effect of calcareous deposition on corrosion is considered for exposures up to 1300 years. The data are derived from archaeological steel and iron shipwrecks, cast iron cannons and cannonballs, and wrought iron anchors in locations where there was direct evidence, in and on the corrosion products, of calcareous deposition. Such deposition promotes formation of calcium and ferrous carbonate layers of low permeability on and within rusts. These tend to inhibit both early and long-term corrosion rates. The data show that up to about 200y exposure corrosion losses as a function of time can be approximated closely by a linear function of time. Longer exposures follow a moderate power-law function, consistent with diffusion considerations. Comments are made about the likely interplay between calcareous deposition and microbiological corrosion.

Effect of long-term immersion corrosion on the flexural properties of nitinol

1982 ◽  
Vol 82 (1) ◽  
pp. 45-49 ◽  
Author(s):  
Bernhard Schwaninger ◽  
Nikhil K. Sarkar ◽  
Benjamin E. Foster
Keyword(s):  
Flexural Properties ◽  
Immersion Corrosion

Corrosion of steels and irons immersed in natural seawater for up to 600 years

CORROSION ◽  
10.5006/3967 ◽  
2021 ◽  
Author(s):  
Robert Melchers
Keyword(s):  
Power Law ◽  
Seawater Temperature ◽  
Bridge Piers ◽  
Natural Seawater ◽  
Outward Diffusion ◽  
Wrought Iron ◽  
Corrosion Loss ◽  
Immersion Corrosion ◽  
Anaerobic Corrosion

Marine immersion corrosion observations for archaeological and other data, including from shipwrecks, wrought iron anchors and cast iron bridge piers are used to estimate corrosion losses in natural unpolluted coastal and near-coastal seawaters for exposures up to about 600 years. Empirical functions for the development of corrosion loss with time were then developed, standardized to 20˚C mean seawater temperature. The resulting slightly non-linear corrosion loss trend, represented by a modified form of the power law, is consistent with Phase 4 of the previously proposed bi-modal corrosion model. These observations support the notion that the rate of long-term corrosion is controlled by outward diffusion, through the rust layers, of gaseous hydrogen generated by the cathodic hydrogen evolution reaction under predominantly anaerobic corrosion conditions. The power-law trend also provides good extrapolation from shorter- term data. For practical purposes for exposures < 100 years in seawaters with mean temperature around 20˚C, a linear model, with longer-term corrosion rate 0.06 mm/y at 20˚C, is sufficiently accurate.

Long-term marine immersion corrosion of welded ABS grade steels

2021 ◽  
pp. 1-9
Author(s):  
Igor A. Chaves ◽  
Robert E. Melchers ◽  
Zoran Sterjovski ◽  
Jeremy Rosen
Keyword(s):  
Immersion Corrosion
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