10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

VS

CE

i (A/cm2)

Fe50

Pd50

FCC (disordered) Mixed Fe

50Pd

50 pT (ordered)

Fe Pd

How do defects and minor solute control the corrosion properties of solid solution alloys?Investigation of the effects of structural (order – disorder transformation, relaxation), chemical (solute clusters, minor solute elements) and structural/chemical defects (solute rich and lean nanocrystals in an amorphous solid solution) were conducted at the nm-scale on corrosion using model engineered materials. • Disordered and ordered crystalline Fe50Pd50 show similar behavior in

acidic Cl- solution, but the disordered structure has strong grain orientation dependent dissolution which is morphologically different than after ordering [1]

• The addition of minor solute elements alters the corrosion resistance of amorphous Al-Cu-Mg based alloys. Ni alloying lowers dissolution rate of Al. Ni also suppresses surface diffusion enabling the formation of a finer porous structure upon dealloying. Dealloying also leads to a rearrangement of Cu to the energetically favorable crystalline phase [2]

CORROSION MECHANISMS IN AMORPHOUS SOLID SOLUTION ALLOYS: Role(s) of Minor Alloying Elements

John R. Scully, University of Virginia Main Campus, DMR 0906663

[1]Disordered

Fe50Pd50

Ordered Fe50Pd50

Cu AlAl

Al

Al

Al

Al Al

Al

Al

Cu

Cu

CuMgMg

Mg

AlCu

Al

Al Al

Al

AlAl

Cu

Mg

Mg

Cu

Al

MgMg

Al

AlCu Mg

Amorphous Alloy with beneficial minor solute

Amorphous Alloy[2]

Key results: Minor alloying element (Ni) plays an important role in the local corrosion behavior as well as dealloying of solid solutions. The solute rich amorphous alloys reorganizes into crystalline structure as dealloying proceeds.

Electrochemistry

Al

MgCu

Al

Al

Al

Al

AlAl

AlAl

AlCu

Cu

Cu

Mg

Mg

Al

Cu

Al

Al

Al

Al

Al

Cu

Cu

CuMg

Mg

Al Cu

Al

AlAl

Cu

Ni

Ni

Ni

10-7 10-6 10-5 10-4 10-3 10-2 10-1 100-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

Pote

ntia

l (V

SCE)

Current Density (A/cm2)

Amorphous alloy with Ni

Amorphous alloy no Ni

Pure Al

With Ni No Ni

Nanoporous Cu formed in pits

30 35 40 45 50 55 60

Exposure time Cu Cu

2O

Al

Inte

nsity

(a.u

.)

2

As-spun

30 sec

200 sec

1000 sec

30 35 40 45 50 55 60

Cu Cu

2O

Al

Inte

nsity

(a.u

.)

2

As-spun

30 sec

200 sec

1000 sec

Exposure time

No NiWith Ni

Crystallization by dealloying

Disordered Fe50Pd50

(100)

(101)

Key result: Structure and compositional ordering play a role in corrosion behavior

EBSDGrain Orientation Index

Corrosion Education• One high school (Martha Fox), 2 Undergraduates (H. Bindig, W.

McCarthy), 3 graduate students (T. Aburada, N. Tailleart, D. Horton), and 1 post-doctoral researchers (H. Ha) contributed to NSF-supported project.

• Graduate & undergraduate, courses in corrosion taught in class and via distance learning (MSE 7080) and MSE 3080 for Made-in-Virginia for Engineers that brings engineering education to workers

• John R. Scully served on National Academy Study on Research

Opportunities In Corrosion (ROCSE). Report due Fall 2010.

(Title) IIName, Institution, DMR Award#

Spatio-temporal Chaos in Systems of Broken Symmetry

Eberhard Bodenschatz, Cornell University, DMR Award#0072077

Outreach • NanoDays participation with nano-scale corrosion applications at local schools and museums • cKITs (a set of corrosion experiments) supplied by National Association of Corrosion Engineers supplied to local K-12 schools• Materials science and engineering demonstrations and lab tours are given to foster an interest in the physical sciences and

materials science.

CORROSION MECHANISMS IN AMORPHOUS ALLOYS: CRITICAL COMPOSITIONAL AND STRUCTURAL DEFECTS FOR LOCAL CORROSION

John R. Scully, University of Virginia Main Campus, DMR 0906663

Awards and Honors• Nicole Tailleart, John R. Scully: Inaugural Award Recipients of the Corrosion Journal Best Paper Award, "User-selectable Barrier,

Sacrificial Anode, and Active Corrosion Inhibiting Properties of Al-Co-Ce Alloys for Coating Applications." NACE International Conference, San Antonio, TX 2010.

• UVA's Center for Electrochemical Science and Engineering received the 2009 NACE Distinguished Organization Award• John R. Scully: received the H.H. Uhlig Award, 2009 of the Electrochemical Society for excellence in corrosion research.• Tomohiro Aburada was: One of twelve invited students internationally to present at Gordon Research Seminar, New London, NH 2010.

Co-authors for Inaugural Best Paper in Corrosion JournalAward Recipients for NSF Funded Work on Amorphous Al-Co-Ce