Final Report - Strategic Environmental Research and Development ...

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REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202- 4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 01-25-2013 FINAL 4. TITLE AND SUBTITLE “Scientific Understanding of Non-Chromated Corrosion Inhibitors Function” 3. DATES COVERED (From - To) March 2008 – August 2012 5a. CONTRACT NUMBER W912HQ-08-C-0011 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Frankel, Gerald S.; Buchheit, Rudolph G.; Jaworowski, Mark; Swain, Greg. 5d. PROJECT NUMBER WP-1620 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) The Ohio State University, Columbus, OH 43210 United Technologies Research Center, East Hartford, CT AND ADDRESS(ES) Michigan State University, Ann Arbor, MI 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) Strategic Environmental Research and Development Program SERDP 4800 Mark Center Drive, Suite 17D08 Alexandria, VA 22350-3605 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION / AVAILABILITY STATEMENT 13. SUPPLEMENTARY NOTES 14. ABSTRACT This project generated understanding of the mechanisms of non-chromate corrosion inhibiting coating systems by studying cross-cutting issues and leading chromate-free chemicals and systems. In Task 1, Trivalent Chromium Process coatings were found to release chromium into solution, which can then form a film on nearby uncoated alloy surface. Transient formation of Cr(VI) was observed, and postulated to form by oxidation of Cr(III) oxide by locally produced H 2 O 2 , which is a product of oxygen reduction. Inhibition in solution by common species found in commercial chromate-free primers was studied: molybdate, silicate, and praseodymium in Task 2, and Ce 3+ , Pr 3+ , La 3+ and Zn 2+ cations in Task 3. A mechanism for inhibition by each species was postulated. In Task 4, effects of surface treatments and roughness on adhesion of coatings were studied using the Blister Test. In Task 5, solubility of modern chromate-free pigments was found to depend on reactions with their environment and with their internal co-pigments, and their transport properties were influenced by ionic current and the fine structure of the primer matrix. Interactions between the various components of Cr-free coating systems were studied in Task 6. In Task 7, Direct Optical Interrogation was used for in-situ monitoring of metallic thin film corrosion underneath organic coating systems. 15. SUBJECT TERMS Al alloys, Non-chromate corrosion-protective coating systems, Non-chromate corrosion inhibitors, Non-chromate surface treatments, Trivalent Chromium Process, Transient formation of Cr(VI), Molybdate, Silicate, Lanthanides, Zinc cations, Coating adhesion, Blister Test, Inhibitor solubility, Inhibitor transport in coatings, Coating component interactions, Under-coating corrosion. 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON Gerald S. Frankel a. REPORT b. ABSTRACT c. THIS PAGE 370 19b. TELEPHONE NUMBER (include area code) 614-688-4128 Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39.18
This report was prepared under contract to the Department of Defense Strategic Environmental Research and Development Program (SERDP). The publication of this report does not indicate endorsement by the Department of Defense, nor should the contents be construed as reflecting the official policy or position of the Department of Defense. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the Department of Defense.
Page 1: FINAL REPORT Scientific Understandi
Page 5 and 6: List of Acronyms AES Atomic Emissio
Page 7 and 8: List of Figures Figure 1.1. Figure
Page 9 and 10: Figure 1.21. Figure 1.22. Figure 1.
Page 15 and 16: Figure 3.11. Cathodic polarization
Page 19 and 20: Figure 4.12. Average Roughness of R
Page 21 and 22: Figure 5.4. Figures 5.5. Apparatus
Page 23 and 24: Figure 5.36. Figure 5.37. R paramet
Page 25 and 26: Figure 6.23. Two commercial samples
Page 27 and 28: Figure 7.1. a) instrumental configu
Page 29 and 30: List of Tables Table 1.1. Table 1.2
Page 31 and 32: Table 6.4. Processing parameters fo
Page 33 and 34: Keywords 1. Al alloys 2. Non-chroma
Page 35 and 36: 1. Executive Summary This report su
Page 37 and 38: the role of electrophoresis in inhi
Page 39 and 40: occurring at low pHs and release at
Page 41 and 42: were obtained by a post treatment w
Page 43 and 44: 4. G.O. Ilevbare, J.R. Scully, J. Y
Page 45 and 46: 3. Objective The primary objective
Page 47 and 48: 5. Results and Accomplishments In t
Page 49 and 50: powder, slurried with ultrapure wat
Page 51 and 52: TCP-coated AA2024-T3. A Kratos AXIS
Page 53 and 54:
X-ray Photoelectron Spectroscopy (X
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Potential (V vs. Ag/AgCl) -0.2 -0.3
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Signal Intensity (counts/s) assessi
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Al (including both Al 0 and Al 3+ c
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TEM or during sample preparation, s
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Potential (V vs. Ag/AgCl) and uncoa
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5.1.4.8 Effects of Aging on the Fil
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Intensity (counts/s) Concentration
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|Z| 0.01Hz (ohm cm 2 ) |Z| 0.01Hz (
Page 71 and 72:
The artificial scratch cell was als
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Raman intensity, a.u. 4000 880 3500
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Figure 1.24. Raman spectra for the
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peak at 520 cm -1 and an intense Cr
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Figure 1.28. Plots of the intensity
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Figure 1.30. (A) Video micrograph o
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The Zr and O signals arise from the
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Figure 1.35. (A) Corrosion potentia
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Table 1.1. Corrosion current (i cor
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additional pitting. The TCP coating
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Figure 1.41. Cr(VI) peak intensity
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Work is ongoing to understand how t
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9. L. Li, D-Y. Kim and G. M. Swain,
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carefully rinsed with DI water, air
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decrease to a net anodic current in
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Potential (mV vs. SCE) Potential (m
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i (A/cm 2 ) Immediately after silic
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Page 107 and 108:
Potential (mV vs. SCE) Rp (ohm.cm 2
Page 109 and 110:
Page 111 and 112:
2.4.4 In situ AFM Scratching Result
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Figure 2.31. In situ AFM scratching
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(2.3) Figure 2.35. Specie diagram f
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concentration and the silicon to ca
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analysis coupled with XPS revealed
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5.2.4.4 In Situ AFM Scratching Befo
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esults in the formation of silicate
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26. P. Schmutz and G.S. Frankel, J.
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Pr 3+ , Y 3+ showed [12] an order o
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0.1M NaCl solution with varying con
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8.7 through pH 12.6 due to the lowe
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(b) (c) 99
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immersed in Ce 3+ remained bright w
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S phase and dissolution of Al matri
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Corrosion rate, i corr (A/cm 2 ) 6x
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I L (microA) 600 500 400 300 NC (-8
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than that of chromate[35]. Historic
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coupon was immersed with the polish
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5.3.2.4 Results 5.3.2.4.1 Speciatio
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(c) Figure 3.8. Speciation diagram
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E vs. SCE (V) -0.70 -0.75 -0.80 -0.
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E vs. SCE (V) 1000 rpm E vs. SCE (V
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Chemical quantification showed a me
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(a) (b) Figure 3.15. (a) (top) SEM
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E vs. SCE (V) E vs. SCE (V) E vs. S
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-Z" (ohm) -Z" (ohm) -Z" (ohm) -Z" (
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(Figure 3.8b). However, no effect o
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CPS CPS CPS x 2 14 10 12 10 8 6 4 2
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CPS CPS 100 95 90 85 80 75 70 x 10
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I k L 0. 2 1 2 AnFC B D 2 3 O 1
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i -800 (A/cm 2 ) 10 -4 NaCl NaCl+5
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Corrosion rate ( 1/R p ) ohm -1 cm
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particles compared to zinc-free sol
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and Zn bentonite compounds have red
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2) Deoxidizing for 3 minutes in an
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Scintag (now ThermoARL) Pad-V TM an
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Table 3.5. Characterization of bent
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Zn 2+ cation release (meq/100g) Pr
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(a) (b) (c) Figure 3.33. (a) An exp
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|Z| (ohm) Phase angle (degrees) 5.3
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|Z| at 0.01 Hz (ohm.cm 2 ) Pore Res
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|Z| at 0.01 Hz (ohm.cm 2 ) |Z| at 0
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pigmented coatings exhibited partia
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5.3.3.6 Conclusions 1. Exchange ben
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39. M. Mahdavian and M. M. Attar, P
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100. F.Liebau, Structural Chemistry
Page 203 and 204:
of the coated sample, which is tigh
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Lubricant Blue (Struers) was used f
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good grip on the dolly, the equipme
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Pressure (kPa) r (mm) Pressure x Ra
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Pressure x Radius (kN/m) plateau bu
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Pressure x Radius (kN/m) Pxr (KN/m)
Page 215 and 216:
Average Roughness (m) In contrast,
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Adhesion Strength (J/m 2 ) PVB PVB
Page 219 and 220:
Pressure (kPa) Constant Infusion up
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(a) (b) (c) (d) Figure 4.19. Coatin
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Min. Potential (V vs SHE) Min. Pote
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Pressure (kPa) exposure in hot wate
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Engineering Stress (MPa) slope of t
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Adhesion Strength (J/m 2 ) ASTM D33
Page 231 and 232:
Pressure (kPa) Pressure (kPa) Radiu
Page 233 and 234:
Adhesion Strength (J/m 2 ) Pressure
Page 235 and 236:
Table 4.7. Adhesion Strength values
Page 237 and 238:
Non-Cl./Deox. No CC Cleaned/Deox. N
Page 239 and 240:
5.4.5 Conclusions and Implications
Page 241 and 242:
5.5 Task 5: Inhibitor Activation an
Page 243 and 244:
solution for equilibration at contr
Page 245 and 246:
Table 5.2. Techniques applied to sp
Page 247 and 248:
The capacitance was determined by E
Page 249 and 250:
combination with zinc molybdate, a
Page 251 and 252:
Concentration, mmol / L Final pH te
Page 253 and 254:
Alkaline affects praseodymium solub
Page 255 and 256:
MoO 4 2- ) inhibition to the system
Page 257 and 258:
Zinc molybdate is reported to be si
Page 259 and 260:
The presence of a salt that has no
Page 261 and 262:
This approach yields two figures of
Page 263 and 264:
Inhibitor mapping of the Hentzen 16
Page 265 and 266:
The molybdate loss in the strontium
Page 267 and 268:
The capacitance dC is given by 0 (
Page 269 and 270:
2 C( r, t) C( r )[1 r 2 exp( D nt
Page 271 and 272:
-thea (degree) logIZI (Ohm-Cm 2 ) P
Page 273 and 274:
Capacitance (F) respectively. The c
Page 275 and 276:
Capacitance (F) Weight gain (g) For
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Normalized Capacitance Change Norma
Page 279 and 280:
Potential V (Ag/AgCl) Corrosion rat
Page 281 and 282:
5.5.4.7 Nanopore structure characte
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Normaalized Transport Rate (g/m^2_d
Page 285 and 286:
S-Parameter S-Parameter Penetration
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S-Parameter S-Parameter Penetration
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R-parameter R-parameter Penetration
Page 291 and 292:
5. T. M. Letcher, “Thermodynamics
Page 293 and 294:
pigment of CaSiO 3 with initial pH
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allowed a comparison of the differe
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The solution resistance (R sol ) va
Page 299 and 300:
Theta [degrees] theta |Z| [ohm] 10
Page 301 and 302:
C [F/cm2] Rcorr [ohm*cm2] 7075-AHN
Page 303 and 304:
C [F/cm 2 ] Rcorr [ohm*cm 2 ] Rcorr
Page 305 and 306:
Visual TTF [hours] Table 6.2. Param
Page 307 and 308:
of Metallast pre-treatment, which h
Page 309 and 310:
Prediction of the TTF obtained by A
Page 311 and 312:
5.6.2 Electrochemical Impedance Spe
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5.6.2.2.1 Coating system descriptio
Page 315 and 316:
Table 6.4. Processing parameters fo
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population of total TTF vectors th
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components of the impedance and the
Page 321 and 322:
Figure 6.17. EIS spectra for sample
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Figure 6.18. Kaplan-Meier survival
Page 325 and 326:
Maximum c i range Maximum ci range
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The type and number of input neuron
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Predicted TTF The BFM method, intro
Page 331 and 332:
The most significant variables to i
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5.6.3 Characterization of Pigment D
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of sputtering gold and carbon paint
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Figure 6.26. Cross-sectional view o
Page 339 and 340:
Figure 6.28. EDX maps of primer cro
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Figure 6.31. EDX maps of primer cro
Page 343 and 344:
In Figure 6.34, Ca and Si existed a
Page 345 and 346:
Table 6.8. Average percentage resid
Page 347 and 348:
strictly limited due to the barrier
Page 349 and 350:
Figure 6.37. Coating systems in det
Page 351 and 352:
Each corrosion volume of scribed ar
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Corrosion Area (mm 2 ) 1200 1000 80
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Corrosion Area (mm 2 ) Corrosion Ra
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Corrosion Rate (mm/yr) Corrosion Vo
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Corrosion Area (mm 2 ) corrosion ra
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corrosion rate (mm/yr) Corrosion Vo
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Corrosion Volume (mm/yr) Corrosion
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ate, PPG CA7233 coated samples had
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Appendix 6B Table 6B.1. Corrosion v
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Table 6B.3. Corrosion rate of sampl
Page 371 and 372:
Table 6B.5. Corrosion area of sampl
Page 373 and 374:
5.7. Task 7: Characterization of Lo
Page 375 and 376:
at 65C. After using DI water to rin
Page 377 and 378:
Transmission Mode Conduct EIS measu
Page 379 and 380:
Cdl(F/cm 2 ) Rp(.cm 2 ) relatively
Page 381 and 382:
pit bottom area (cm 2 ) pit bottom
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2days 2days 1mm 1mm 7days 7days Pit
Page 385 and 386:
(a) (b) Si Si O Al Na Ca K Si Al-Cu
Page 387 and 388:
Pit 1 and pit 2 as shown in Figure
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In these experiments, Deft primers
Page 391 and 392:
For the case of as-deposited thin f
Page 393 and 394:
3. L. Balazs, Physica E, 54, 1183-1
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and subsequently re-oxidized in two
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not represent true adhesion strengt
Page 399 and 400:
• The pit morphology in 0.5 M NaC
Page 401 and 402:
Appendix 2. List of Scientific/Tech
Page 403 and 404:
“The Secret Life of Chromate Free
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