Center for Corrosion Science and Engineering

Washington, DC, United States

Center for Corrosion Science and Engineering

Washington, DC, United States

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News Article | April 11, 2016

A five-member team of researchers from the U.S. Naval Research Laboratory (NRL) Center for Corrosion Science and Engineering received the Office of Naval Research (ONR) Prize for Affordability, Aug. 26, at an award ceremony held at ONR in Alexandria, Va. The award honors materials research engineers James Martin, head of the Marine Coatings Science Section, Jimmy Tagert, and John Wegand; research chemist, Dr. Erick Iezzi; and physical scientist technician, Paul Slebodnick for significant contributions to an overall reduction in the total ownership costs associated with corrosion control of Navy ships and submarines and achievements in the development and transition of nonskid and topside coatings to the fleet. The team formulated, synthesized, and commercialized topside and nonskid coatings having longer life, high durability, improved weathering resistance and color stability, to replace both legacy nonskid decking and topside coatings. The Navy installs nearly 3.7 million square feet of non-skid coatings per year that typically cost over $56 million annually. Conventional epoxy based nonskids have a 12 to 36 month lifecycle, while topside coatings have a 24 to 36 month life. The new NRL-developed polysiloxane system doubles or triples the life expectancy of this system. For topside coatings, not only are lifetimes increased, but also installation costs are reduced by up to 28 percent through the reduced number of coats over conventional systems. As a result, polysiloxane coatings systems have been qualified and approved for use by Naval Sea Systems Command (NAVSEA) and have been mandated for all topside depot level maintenance availabilities. The NRL polysiloxane nonskid decking system is planned for qualification in 2015. At present, the nonskid coatings system has exceeded the one-year flight deck requirement on-board the USS Theodore Roosevelt (CVN 71), has outperformed all previous nonskids on-board the USS Michigan (SSGN 727), and is still performing well on-board the USS Bulkeley (DDG 84). On Navy submarines, this system is the only system ever to pass the submarine nonskid requirements. The Center for Corrosion Science and Engineering (CCSE) conducts broad scientific and engineering programs to understand and reduce the effects of the marine environment on naval systems. Within the CCSE, the Marine Coatings Science Section conducts basic and applied research to synthesize and produce advanced, multi-functional marine coatings technology for all naval environments including immersion, alternate immersion and atmospheric exposures typical of Navy and Marine Corps platforms. About the U.S. Naval Research Laboratory The U.S. Naval Research Laboratory provides the advanced scientific capabilities required to bolster our country's position of global naval leadership. The Laboratory, with a total complement of approximately 2,500 personnel, is located in southwest Washington, D.C., with other major sites at the Stennis Space Center, Miss., and Monterey, Calif. NRL has served the Navy and the nation for over 90 years and continues to advance research further than you can imagine. For more information, visit the NRL website or join the conversation on Twitter, Facebook, and YouTube.

Policastro S.A.,Center for Corrosion Science and Engineering | Hangarter C.M.,Excet Inc. | Horton D.J.,Center for Corrosion Science and Engineering | Wollmershauser J.A.,U.S. Navy | Roeper D.F.,Excet Inc.
Journal of the Electrochemical Society | Year: 2016

The electrochemical behavior of oxides of three Ti-based binary alloys, Ti99Co1, Ti99Sn1, and Ti99Cr1, are investigated using electrochemical impedance spectroscopy, Mott-Schottky analysis and cyclic voltammetry. It is found that native amorphous TiO2 can be doped in order to change the oxide's electronic properties and thereby reduce oxygen reduction rates in an alkaline solution, with the greatest reduction seen for the Ti99Sn1 alloy. © 2016 The Electrochemical Society.

Hangarter C.M.,Excet Inc. | Policastro S.A.,Center for Corrosion Science and Engineering | Martin F.J.,Center for Corrosion Science and Engineering
ECS Transactions | Year: 2015

A mechanistic understanding of how electrolyte composition and metal oxide can influence corrosion kinetics in the electrolytes formed from atmospheric processes is investigated. Galvanic couples between aluminum alloys and titanium or stainless steel fasteners exposed to electrolytes formed from atmospheric processes lead to very different corrosion rates. The differences in cathodic current capacity for materials exposed to the same electrolyte at the same aeration level reinforces the fact that oxide microstructure plays a role in catalyzing reduction reactions, though the kinetics of the reaction rates may not be predicted from a simple galvanic series. Also of interest are the changes in reaction rates from acidification of the electrolyte. This suggests that the electrolyte is changing the oxide microstructure or that new reduction reactions are supported and that material loss rates can be orders of magnitude higher for acidified atmospheric electrolytes. © The Electrochemical Society.

Williams K.,Center for Corrosion Science and Engineering | Williams K.,Pennsylvania State University | Bayles R.,Center for Corrosion Science and Engineering | Natishan P.,Center for Corrosion Science and Engineering | And 2 more authors.
ECS Transactions | Year: 2012

When as-received or sensitized AA5083 are immersed in an electrolyte, a growing crack creates a galvanic couple with the external surfaces according to the differential aeration hypothesis. Monitoring the resulting "coupling current" yields information about the mechanisms of crack advance. The purpose of this study is to determine if the scanning vibrating electrode technique (SVET) can be used to monitor the coupling current flowing through the solution from the crack to the external surfaces. If successful, this method, which maps potential as a function of probe position via a scanning vibrating probe (SVP), can be used to visualize and quantify the coupling current emanating from a growing stress corrosion crack in sensitized and unsensitized aluminum alloy samples to yield more localized information about the crack growth process. Preliminary feasibility studies were performed to map the current/potential in larger galvanic couples designed to simulate Cu-rich intermetallics dispersed in an aluminum matrix (as in the Cu-rich particles in AA2024 and Mgrich intermetallics in AA5083). A fracture mechanics apparatus, designed to apply a known stress intensity, was employed to reveal the onset of subcritical crack growth. The final goal is to combine the typical fracture mechanics testing with the SVET and acoustic emissions. We report on the progress that has been made in designing a customized four-point bend, fracture mechanics device that allows for simultaneous loading and electrochemical mapping. Future work will report data gathered from in-situ electrochemical and acoustic emissions testing on pre-cracked AA5083 specimens. © The Electrochemical Society.

Heuer A.H.,Case Western Reserve University | Kahn H.,Case Western Reserve University | O'Donnell L.J.,Case Western Reserve University | Ernst F.,Case Western Reserve University | And 4 more authors.
Electrochemical and Solid-State Letters | Year: 2010

Interstitial hardening of the martensitic stainless steel PH13-8 Mo has been achieved by low temperature gas-phase carburization. After treatment, hardness is increased to a depth of ≈50 μm, with a surface hardness that is twice the core hardness and a corresponding improvement in pin-on-disk wear resistance. Pitting potential is increased by ≈0.5 V in 0.6 M NaCl. Elemental analysis and X-ray diffraction suggest the formation of a thin (≈2 μm) carbidic surface layer that is both wear and corrosion resistant. © 2010 The Electrochemical Society.

Zhai J.,University of Akron | Luo T.,University of Akron | Gao X.,University of Akron | Graham S.M.,U.S. Naval Academy | And 3 more authors.
International Journal of Solids and Structures | Year: 2016

This paper presents a constitutive model, which combines the models proposed by Stewart and Cazacu (2011) and Zhou et al. (2014), to describe the ductile damage process in a commercially pure titanium (CP Ti) and to simulate its mechanical response. In particular, a Gurson-type porous material model is modified by coupling two damage parameters, accounting for the void damage and the shear damage respectively, into the yield function and the flow potential. The plastic anisotropy and tension-compression asymmetry exhibited by CP Ti are accounted for by a plasticity model based on the linear transformation of the stress deviator. The theoretical model is implemented in the general purpose finite element software ABAQUS via a user defined subroutine and calibrated using experimental data. Good comparisons are observed between model predictions and experimental results for a series of specimens in different orientations and experiencing a wide range of stress states. © 2016.

Kahn H.,Case Western Reserve University | Heuer A.H.,Case Western Reserve University | Michal G.M.,Case Western Reserve University | Ernst F.,Case Western Reserve University | And 5 more authors.
Surface Engineering | Year: 2012

The mechanical properties and corrosion resistance of duplex (ferrite-austenite) grade 2205 stainless steel have been substantially improved by interstitial hardening using low temperature carburisation. The austenite phase of the duplex stainless steel responds to low temperature carburisation in a similar manner as single phase austenitic stainless steels, forming 'expanded' austenite (also called S phase). The surface layer that forms on the ferritic portion of 2205 steel consists of a paraequilibrium carbide, a carbide with the same metal composition as the underlying ferrite. This two-phase case has about three times the Vickers hardness of non-treated material, an improved ultimate tensile strength and increased fatigue resistance, and much improved crevice corrosion resistance. © 2012 Institute of Materials, Minerals and Mining.

Policastro S.A.,U.S. Naval Academy | Auyeung R.C.Y.,U.S. Navy | Martin F.J.,Center for Corrosion Science and Engineering | Rayne R.J.,U.S. Navy | And 4 more authors.
Journal of the Electrochemical Society | Year: 2012

A novel experimental technique for making electrochemical measurements on individual phase or isolated regions of a metal or alloy is reported. The technique, called Selective Masking by Photolithography (SMP), uses a hardened photoresist coating to mask the excluded portions of the sample and 355 nm laser pulses are employed to expose individual grains or regions of interest. The size of the exposed area can range from tens of microns to millimeters. Localized electrochemical DC and AC measurements and critical pitting temperature determinations for the two phases in a duplex stainless steel were used to show the utility and viability of SMP. © 2011 The Electrochemical Society.

Williams K.,Center for Corrosion Science and Engineering | Bayles R.,Center for Corrosion Science and Engineering | Macdonald D.D.,University of California at Berkeley
Advanced Materials and Processes | Year: 2013

A unique horizontal fracture mechanics device was developed to examine AA5083 bend bars mechanically and electrochemically using a scanning vibrational probe to detect and characterize the coupling current flowing from the crack to external surface, where it is annihilated by a cathodic charge transfer reaction (e.g., hydrogen evolution or oxygen reduction). Hence, the coupling current from the crack was spatially resolved while the specimen was actively loaded. The notch is active during loading and becomes more passive toward the end of the experiment. With knowledge from previous fracture mechanics studies on wedge-opening-load samples, the onset of subcritical crack growth was verified with the aid of an extensometer or clip gauge. Together with results of studies now underway, crack growth mechanisms may be more fully understood with regard to different sensitized alloys that undergo stress corrosion cracking.

Holtz R.L.,U.S. Navy | Pao P.S.,U.S. Navy | Bayles R.A.,Center for Corrosion Science and Engineering | Longazel T.M.,Center for Corrosion Science and Engineering | Goswami R.,SAIC
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2012

The fatigue crack growth behavior of aluminum alloy 5083-H131 has been systematically studied as a function of degree of sensitization for aging at 448 K (175C). Fatigue crack growth rates were measured at load ratios of 0.1 and 0.85, in vacuum, air, and a corrosive aqueous environment containing 1 pct NaCl with dilute inhibitor. Sensitization does not affect the fatigue crack growth behavior of Al 5083-H131 significantly in vacuum or air, at low- or high-load ratio. For high-load ratio, in the 1 pct NaCl+inhibitor solution, the threshold drops by nearly 50 pct during the first 200 hours of aging, then it degrades more slowly for longer aging times up to 2000 hours. The change in aging behavior at approximately 200 hours seems to be correlated with the transition from partial coverage of the grain boundaries by b Al3Mg2 phase, to continuous full b coverage. ASTMG-67mass loss levels below approximately 30 mg/cm2 do not exhibit degraded corrosion-fatigue properties for R = 0.85, but degradation of the threshold is rapid for higher mass loss levels. © The Minerals, Metals & Materials Society and ASM International 2011.

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