Research Article Boric Acid as an Accelerator of …downloads.hindawi.com/journals/ijc/2014/128720.pdfto protect the aluminum as well or better than chromate treatments. e purpose

Research ArticleBoric Acid as an Accelerator of Cerium SurfaceTreatment on Aluminum

K Cruz-Hernaacutendez S Loacutepez-Leon and F J Rodriacuteguez-Goacutemez

Departamento de Ingenierıa Metalurgica Edificio D Facultad de Quımica Universidad Nacional Autonoma de MexicoEdificio D Ciudad Universitaria 04510 Mexico DF Mexico

Correspondence should be addressed to K Cruz-Hernandez karycruzhgmailcom

Received 12 October 2013 Accepted 4 December 2013 Published 16 January 2014

Academic Editor Benjamin Valdez Salas

Copyright copy 2014 K Cruz-Hernandez et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Aluminum pieces are often used in various industrial processes like automotive and aerospace manufacturing as well as inornamental applications so it is necessary to develop processes to protect these materials processes that can be industrializedto protect the aluminum as well or better than chromate treatments The purpose of this research is to evaluate boric acid asan accelerator by optimizing its concentration in cerium conversion coatings (CeCC) with 10-minute immersion time with aconcentration of 01 g Lminus1 over aluminum to protect it The evaluation will be carried out by measuring anticorrosion propertieswith electrochemical techniques (polarization resistance119877

119901

polarization curves PC and electrochemical impedance spectroscopyEIS) in NaCl 35 wt aqueous solution and surface characterization with scanning electron microscopy (SEM)

1 Introduction

Among the most striking characteristics of aluminum is itsversatility and the range of physical and mechanical proper-ties that can be developed is remarkable The properties ofaluminum that make this metal and its alloys the most eco-nomical and attractive options for a wide variety of uses areappearance light weight manufacturing versatility physicalproperties mechanical properties and corrosion resistance[1] Aluminum and its alloys are widely used in automotiveand aerospace devices Sometimes pieces of an aircraft aresubmitted to aggressive environments and changes of temper-ature as well as condensation resulting in corrosion attack onthem

For many years research for alternatives to chromatizingin order to diminish the damage to the environment has beencarried out Treatments that led to the development of othernontoxic coating processes with comparable adhesion prop-erties and corrosion protection such as conversion pretreat-ments formed by immersion in solutions containing phos-phates or cerium chloride or other rare earth metal chlo-rides such as yttrium and lanthanumhave been studied [2ndash5]

Approaches to cerium conversion coatings include dif-ferent salts variation on immersion temperature anodizingapplyingmany layers variation in concentration surface acti-vation and use of accelerators like hydrogen peroxide [6ndash19]

The aim of this work is to improve understanding ofaccelerators on cerium conversion coatings by studying theeffect of different concentrations of boric acid as an accelera-tor added to CeCC at 01 g Lminus1 at 60∘C and the role playedby the substrate composition The corrosion performanceof treated aluminum surfaces that immersed 10 minutesin a cerium solution (01 g Lminus1 CeCl

3

sdot7H2

O and dissolvedin 01M NaCl) was analyzed The electrochemical measure-ments were performed in a 35 wt NaCl aqueous solutionand their response was correlated to the morphology andelemental composition

2 Experimental Process

In this study aluminum sheets used for testing had an areaof 40 cm2 and a 1mm thickness with a nominal compositionshown in Table 1 Before immersion metallic samples werecleaned and degreased using acetoneThe cerium conversion

Hindawi Publishing CorporationInternational Journal of CorrosionVolume 2014 Article ID 128720 6 pageshttpdxdoiorg1011552014128720

2 International Journal of Corrosion

(a) (b)

(c) (d)

Figure 1 SEM images of aluminum conversion layers in cerium bath (01 g Lminus1) at different concentrations of accelerator (boric acid) (a) 0(b) 01 (c) 05 and (d) 1 g Lminus1

Table 1 Aluminum composition wt

Mg Mn Fe Si Cr Cu Ti Al00050 00109 00794 03201 00010 00633 00199 Balance

coatings (CeCC) were obtained by dipping the samples intothe cerium bath that was 01M NaCl solution containing01 g Lminus1 CeCl

3

sdot7H2

O and boric acid as an accelerator (0 0105 and 1 g Lminus1) at 60∘C for 10minutesThe coatingswere thendried in warm air before any further handling or analysis

Morphological aspects of the substrates and the conver-sion layers were studied by scanning electron microscopy(SEMEDS) JEOL JSM-35C equipped with an EDS VoyagerTracorNorthern Spectrometer Chemical species distributionwas also evaluated by EDS analysis

Electrochemical characterization comprising polariza-tion resistance (119877

119901

) polarization curves (PC) and AC impe-dance (EIS) was performed on the specimens treated withCeCC with and without accelerator The samples were testedin a NaCl 35 wt aqueous solution at room temperature Astandard three-electrode setup and an electrochemical celldesigned to work at room temperature were utilized The cellconsisted of an acrylic rectangular box (60 times 80 times 100mm)with an exposed sample area of 0785 cm2 The specimenswere introduced by moderate pressure against an O-ringavoiding localized damage on the cerium-based layer

The counter-electrode was a large-area graphite bar andthe reference electrode was a saturated calomel electrode

SCE The electrochemical measurements were obtained withan AC Gill potentiostat-galvanostat instrument connected toa personal computer

Electrochemical impedance spectroscopy (EIS) was per-formed in the frequency range from 104 to 10minus1Hz with tenmeasured points per frequency decade with amplitude of10mVRMS open-circuit potential

3 Results and Discussion

The SEM pictures of the cleaned and treated specimens areshown in Figure 1 It can be seen that the conversion coatingsgrew without a preferential direction since they presentedbasically the same morphology as the bare substrates

Figure 1 shows the micrographs for aluminum beforeadding the accelerator to the CeCC the micrographs foraluminum showed some crystalline aggregates without apreferential direction (Figure 1(a)) Using boric acid as anaccelerator at 01 g Lminus1 the nucleation of the CeCC increasedthe crystalline aggregates (Figure 1(b)) similarly at 05 g Lminus1of boric acid the influence of the substrate the microstruc-ture and the topography on the treatmentrsquos growth areobserved as white points (Figure 1(c)) Finally the CeCCobtained at 1 g Lminus1 shown in Figure 1(d) appeared as smallercrystals than in 05 g Lminus1 similar to the sample with 01 g Lminus1Moreover observing Figures 1(a) to 1(d) itmay be noticed thatthe coating growth was in the form of aggregates that doped

International Journal of Corrosion 3

Table 2 EDS Analysis for the elements and normalized results

05 gL H3BO3

Element Reaction area Matrix (uncovered area)Atomic ()

O 3074 1856Na 131 121Al 6681 7912Cl 077 110Ce 037Total 10000 10000

2500

2000

1500

1000

500

0

0 5 10

Cou

nts O

CeNa

Si Cl CeCeCu

Al

Energy (keV)

Figure 2 EDS spectra of analysis of the elements

the native oxide of aluminum but did not constitute a contin-uous film as typically some oxidants do on a film surface

Table 2 shows the EDS analysis of the aluminum samplesobtained after the conversion treatment while Figure 2 showsspectra for analysis (where copper was discarded in thequantification because it was an impurity in the ceriumchloride solution as determined by atomic absorption)Thesestudies were performed in zones not covered by the CeCCand in an area where CeCC covered the substrate only for05 g Lminus1 of the accelerator sample The table shows that thecomposition is quite different for each case but the aluminumconcentration is hugely diminished evidencing the formationof other species like Ce(III) oxide and a thicker aluminumoxide (alumina) layer Similar behavior was obtained forthe oxygen content that increased following the oppositetrending which could be related to alumina andCe(III) oxidelayer formation

This work studied the effect of different concentrationsof boric acid as an accelerator on CeCC baths and the roleplayed by the substrate composition in this solution at 60∘CThe results obtained by SEM indicated that the formation andgrowth of CeCCon aluminumwere not uniformover the sur-face the heterogeneous distribution could be due to increasein the silicon concentration (Table 3 performed by statisticaltreatments of the 220 test of EDS analysis) that brings aboutformation of crystalline aggregates and promotes localizedattack Finally it appears that the formation of CeCC couldnot produce a fully covered surface of specimens at higheraccelerator concentration

0

5000

10000

15000

20000

01 05 1Concentration of accelerator (gL)

Pola

rizat

ion

resis

tanc

e (Ω

)

Figure 3 Polarization resistance values for Al samples treated withCeCC for different accelerator concentrations

SEM analysis showed that a very thin film was formed onthese substrates as a result of the cerium treatment and evenobtained a better coat of cerium at the optimum concentra-tion of accelerator

Figure 3 summarizes the polarization resistance (119877119901

) dataobtained for substrates with and without accelerator at differ-ent concentrations on the cerium treatment Comparing thebehavior of the coatings produced at different concentrationsof the accelerator it will be seen that 05 g Lminus1 samples haveshown the highest 119877

119901

and showed a better protection againstcorrosion (18167Ω times cm2)

Anodic polarization curves for aluminum specimens inNaCl 35 wt are presented in Figure 4 The anodic curvesshow that the presence of an accelerator diminishes elec-trochemical activity and at 05 g Lminus1 the curve shows lowercurrent densities than for other concentrations Although theelectrochemical properties were different it is demonstratedthat the best behaviorwas obtained for 05 g Lminus1 of accelerator

This behavior can be attributed to the formation of oxidesof cerium in which hydrogen peroxide acts as accelerator inoxide formation because the standard reaction is producedby an increase of pH coming from the reduction of oxygenfavored by oxidation of metal If hydrogen peroxide is addedthe reaction occurs faster due to the formation of hydroxylions coming from direct reduction of hydrogen peroxidebut if hydrogen peroxide decomposes into oxygen oxygenreduction could occur [13 20ndash22]

O2

+ 2H2

O + 4eminus 997888rarr 4OHminus (1)

H2

O2

+ 2H+ + 2eminus 997888rarr 2H2

O (2)

H2

O2

+ 2eminus 997888rarr 2OHminus (3)

Also it has been proposed [10 23] that the formationof oxides of Ce(III) and Ce(IV) occurs using boric acid asaccelerator this formation could be due to the reduction ofboric acid resulting in local alkalinization No thermal effecton boric acid decomposition has been reported so its effect


Table 3 Statistical treatments of 220 test of EDS analysis

Element

01 gL H3BO3 05 gL H3BO3 1 gL H3BO3

Atomic Atomic Atomic

Minimum Average Maximum Standarddeviation Minimum Average Maximum Standard

deviation Minimum Average Maximum Standarddeviation

O 192 1201 3025 684 326 1446 3247 712 009 1119 2693 597Na 009 095 1132 166 001 068 643 084 006 105 107 188Al 4033 8437 9754 924 1912 8494 962 1013 6653 8591 9938 638Si 003 132 4574 462 003 186 6512 674 001 034 273 031Cl 003 114 1143 192 003 083 758 100 005 133 1309 228Fe 003 018 141 015 008 018 14 016 005 018 056 009Ce 007 024 028 005 01 04 047 008 007 005 009 003

01051

minus1000

minus900

minus800

minus700

minus600

minus500

minus400

minus300

minus200

minus100

0

minus6 minus5 minus4 minus3 minus2 minus1 0 1 2

E(m

V ve

rsus

ECS

)

log |i|

(a)

0

5

10

15

20

25

30

35

01051

minus5

minus1000 minus800 minus600 minus400 minus200 0

I(m

Ac

m2 )

E (mV)

(b)

Figure 4 Polarization curves (a) and voltammograms (b) for aluminum conversion layers in cerium bath (01 g Lminus1) at differentconcentrations of accelerator (boric acid) 01 05 and 1 g Lminus1 Evaluated in NaCl 35 wt aqueous solution

could be continuous during immersion even if the solutionis heated

Results for the electrochemical impedance spectroscopyobtained for aluminum specimens inNaCl 35wt are shownin Figures 5(a)ndash5(c) All plots obtained showed depressedsemicircles Nyquist plots (Figure 5(a)) show semicircles withchanges in diameter attaining a maximum value for 05 g Lminus1of accelerator sample which is a trend also observed inthe phase impedance modulus versus log119891 Bode diagrams(Figure 5(b)) The phase angle versus log119891 Bode diagramsfor the specimens (Figure 5(c)) showed two time constantsand higher phase angles for the samples containing 05 g Lminus1of accelerator

AC impedance results indicate that due to the roughnessof the substrate generated during the CeCC treatment thesurface can be modified by a localized attack which maycause a decrease of the corrosion protection and changes

in the solutionrsquos resistance The higher impedances for thetreated samples match the results obtained by 119877

119901

PC andSEM observations and indicate a strong dependence ofthe chemical conversion treatments on the substrate Somedifferences can be observed in the resistance solution andare attributed to the alumina layer formation and indicate ahigher anticorrosive performance at 05 g Lminus1 of boric acid

4 Conclusions

Theresults indicate that the conversion coatings grewwithouta preferential direction The electrochemical test indicatedthat an optimum anticorrosive protection for the specimensevaluated might be achieved at 05 g Lminus1 of boric acid intothe cerium bath The uniformity and possibly the thicknessof the CeCC seem to increase with the concentration of anaccelerator but beyond 05 g Lminus1 it decreases again and this


60000

40000

20000

0

0 20000 40000 60000

10000

5000

00 5000 10000

CeCCCeCC + H3BO3

|Z|

(Ω)

|Z| (Ω)

(a)

105

104

103

102

101

100

10minus1

Frequency (Hz)10

410

310

210

110

0

CeCCCeCC + H3BO3

|Z|

(Ω)

(b)

90

80

70

60

50

40

30

20

10

Phas

e ang

le (d

eg)

10minus1

Frequency (Hz)10

410

310

210

110

0

CeCCCeCC + H3BO3

(c)

Figure 5 Nyquist and zoom of Nyquist (a) and Bode ((b)-(c)) impedance plots for treated and untreated aluminium samples in a 35 wtNaCl aqueous solution

could modify the surface by localized attack thus reducingthe anticorrosive protection

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors wish to thank the support from project PAPIITIN105809 Karina Cruz also appreciates the financial supportfrom Consejo Nacional de Ciencia y Tecnologıa (CONA-CYT) (PhD Scholarship) and Ivan Puente Lee for performingSEM and EDS analysis

References

[1] E L Rooy ldquoIntroduction to aluminum and aluminum alloysrdquoin ASMMetals Handbook vol 2 ASM International 1990

[2] L Fedrizzi F Deflorian S Rossi L Fambri and P L BonoraldquoStudy of the corrosion behaviour of phosphatized and paintedindustrial water heatersrdquo Progress in Organic Coatings vol 42no 1-2 pp 65ndash74 2001

[3] G Li L Niu J Lian and Z Jiang ldquoA black phosphate coatingfor C1008 steelrdquo Surface and Coatings Technology vol 176 no2 pp 215ndash221 2004

[4] L Fedrizzi F Deflorian and P L Bonora ldquoCorrosion behaviourof fluotitanate pretreated and painted aluminium sheetsrdquo Elec-trochimica Acta vol 42 no 6 pp 969ndash978 1997


[5] B RWHinton and LWilson ldquoThe corrosion inhibition of zincwith cerous chloriderdquo Corrosion Science vol 29 no 8 pp 967ndash985 1989

[6] M Bethencourt F J Botana M J Cano andM Marcos ldquoHighprotective environmental friendly and short-time developedconversion coatings for aluminium alloysrdquo Applied SurfaceScience vol 189 no 1-2 pp 162ndash173 2002

[7] B Y Johnson J Edington A Williams and M J OrsquoKeefeldquoMicrostructural characteristics of cerium oxide conversioncoatings obtained by various aqueous deposition methodsrdquoMaterials Characterization vol 54 no 1 pp 41ndash48 2005

[8] M Bethencourt F J Botana M J Cano and M MarcosldquoAdvanced generation of green conversion coatings for alu-minium alloysrdquo Applied Surface Science vol 238 no 1ndash4 pp278ndash281 2004

[9] M Dabala L Armelao A Buchberger and I Calliari ldquoCerium-based conversion layers on aluminum alloysrdquo Applied SurfaceScience vol 172 no 3-4 pp 312ndash322 2001

[10] Y Xingwen C Chunan Y Zhiming Z Derui and Y ZhongdaldquoStudy of double layer rare earth metal conversion coating onaluminum alloy LY12rdquoCorrosion Science vol 43 no 7 pp 1283ndash1294 2001

[11] W Zhang J Q Li Y S Wu J T Xu and K Chen ldquoCorrosionresistance of conversion film formed on aluminium alloy usingcerium salt surface treatmentrdquo Surface Engineering vol 18 no3 pp 224ndash227 2002

[12] A Decroly and J Petitjean ldquoStudy of the deposition of ceriumoxide by conversion on to aluminium alloysrdquo Surface andCoatings Technology vol 194 no 1 pp 1ndash9 2005

[13] M A Arenas and J J de Damborenea ldquoGrowth mechanisms ofcerium layers on galvanised steelrdquo Electrochimica Acta vol 48no 24 pp 3693ndash3698 2003

[14] M A Arenas M Bethencourt F J Botana J de Damboreneaand M Marcos ldquoInhibition of 5083 aluminium alloy andgalvanised steel by lanthanide saltsrdquo Corrosion Science vol 43no 1 pp 157ndash170 2001

[15] W G Faherenheltz O rsquoKeefe MJ H Zhou and J T GrantldquoCharacterization of cerium-based conversion coatings forcorrosion protection of aluminum alloysrdquo Surface and CoatingsTechnology vol 155 no 2-3 pp 208ndash213 2002

[16] B Y Johnson J Edington and M J OrsquoKeefe ldquoEffect of coatingparameters on the microstructure of cerium oxide conversioncoatingsrdquoMaterials Science and Engineering A vol 361 no 1-2pp 225ndash231 2003

[17] P Campestrini H Terryn A Hovestad and J H W de WitldquoFormation of a cerium-based conversion coating on AA2024relationship with the microstructurerdquo Surface and CoatingsTechnology vol 176 no 3 pp 365ndash381 2003

[18] Y Liu M A Arenas A de Frutos et al ldquoInfluence of nitric acidpre-treatment on Al-Cu alloysrdquo Electrochimica Acta vol 53 no13 pp 4454ndash4460 2008

[19] JM Sanchez-AmayaM Bethencourt L Gonzalez-Rovira andF J Botana ldquoNoise resistance and shot noise parameters onthe study of IGC of aluminium alloys with different heattreatmentsrdquo Electrochimica Acta vol 52 no 23 pp 6569ndash65832007

[20] A H Scott Y Pu T OrsquoKeefe and M OrsquoKeefe ldquoThe phase sta-bility of cerium species in aqueous systems I E-pH diagram forthe systemrdquo Journal of the Electrochemical Society vol 149 no12 pp C623ndashC630 2002

[21] C Motte N Maury M G Olivier J P Petitjean and J FWillem ldquoCerium treatments for temporary protection of elec-troplated steelrdquo Surface and Coatings Technology vol 200 no 7pp 2366ndash2375 2005

[22] L Arurault P Monsang J Salley and R S Bes ldquoElectrochem-ical preparation of adherent ceria coatings on ferritic stainlesssteelrdquoThin Solid Films vol 466 no 1-2 pp 75ndash80 2004

[23] X Yu and G Li ldquoXPS study of cerium conversion coating onthe anodized 2024 aluminum alloyrdquo Journal of Alloys and Com-pounds vol 364 no 1-2 pp 193ndash198 2004

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


(a) (b)

(c) (d)

Figure 1 SEM images of aluminum conversion layers in cerium bath (01 g Lminus1) at different concentrations of accelerator (boric acid) (a) 0(b) 01 (c) 05 and (d) 1 g Lminus1

Table 1 Aluminum composition wt

Mg Mn Fe Si Cr Cu Ti Al00050 00109 00794 03201 00010 00633 00199 Balance

coatings (CeCC) were obtained by dipping the samples intothe cerium bath that was 01M NaCl solution containing01 g Lminus1 CeCl

3

sdot7H2

O and boric acid as an accelerator (0 0105 and 1 g Lminus1) at 60∘C for 10minutesThe coatingswere thendried in warm air before any further handling or analysis

Morphological aspects of the substrates and the conver-sion layers were studied by scanning electron microscopy(SEMEDS) JEOL JSM-35C equipped with an EDS VoyagerTracorNorthern Spectrometer Chemical species distributionwas also evaluated by EDS analysis

Electrochemical characterization comprising polariza-tion resistance (119877

119901

) polarization curves (PC) and AC impe-dance (EIS) was performed on the specimens treated withCeCC with and without accelerator The samples were testedin a NaCl 35 wt aqueous solution at room temperature Astandard three-electrode setup and an electrochemical celldesigned to work at room temperature were utilized The cellconsisted of an acrylic rectangular box (60 times 80 times 100mm)with an exposed sample area of 0785 cm2 The specimenswere introduced by moderate pressure against an O-ringavoiding localized damage on the cerium-based layer

The counter-electrode was a large-area graphite bar andthe reference electrode was a saturated calomel electrode

SCE The electrochemical measurements were obtained withan AC Gill potentiostat-galvanostat instrument connected toa personal computer

Electrochemical impedance spectroscopy (EIS) was per-formed in the frequency range from 104 to 10minus1Hz with tenmeasured points per frequency decade with amplitude of10mVRMS open-circuit potential

3 Results and Discussion

The SEM pictures of the cleaned and treated specimens areshown in Figure 1 It can be seen that the conversion coatingsgrew without a preferential direction since they presentedbasically the same morphology as the bare substrates

Figure 1 shows the micrographs for aluminum beforeadding the accelerator to the CeCC the micrographs foraluminum showed some crystalline aggregates without apreferential direction (Figure 1(a)) Using boric acid as anaccelerator at 01 g Lminus1 the nucleation of the CeCC increasedthe crystalline aggregates (Figure 1(b)) similarly at 05 g Lminus1of boric acid the influence of the substrate the microstruc-ture and the topography on the treatmentrsquos growth areobserved as white points (Figure 1(c)) Finally the CeCCobtained at 1 g Lminus1 shown in Figure 1(d) appeared as smallercrystals than in 05 g Lminus1 similar to the sample with 01 g Lminus1Moreover observing Figures 1(a) to 1(d) itmay be noticed thatthe coating growth was in the form of aggregates that doped



05 gL H3BO3


O 3074 1856Na 131 121Al 6681 7912Cl 077 110Ce 037Total 10000 10000

2500

2000

1500

1000

500

0

0 5 10

Cou

nts O

CeNa

Si Cl CeCeCu

Al

Energy (keV)





0

5000

10000

15000

20000


Pola

rizat

ion

resis

tanc

e (Ω

)





119901




O2

+ 2H2


H2

O2


O (2)

H2

O2





Element





O 192 1201 3025 684 326 1446 3247 712 009 1119 2693 597Na 009 095 1132 166 001 068 643 084 006 105 107 188Al 4033 8437 9754 924 1912 8494 962 1013 6653 8591 9938 638Si 003 132 4574 462 003 186 6512 674 001 034 273 031Cl 003 114 1143 192 003 083 758 100 005 133 1309 228Fe 003 018 141 015 008 018 14 016 005 018 056 009Ce 007 024 028 005 01 04 047 008 007 005 009 003

01051

minus1000

minus900

minus800

minus700

minus600

minus500

minus400

minus300

minus200

minus100

0


E(m

V ve

rsus

ECS

)

log |i|

(a)

0

5

10

15

20

25

30

35

01051

minus5


I(m

Ac

m2 )

E (mV)

(b)






119901


4 Conclusions



60000

40000

20000

0

0 20000 40000 60000

10000

5000

00 5000 10000

CeCCCeCC + H3BO3

|Z|

(Ω)

|Z| (Ω)

(a)

105

104

103

102

101

100

10minus1

Frequency (Hz)10

410

310

210

110

0

CeCCCeCC + H3BO3

|Z|

(Ω)

(b)

90

80

70

60

50

40

30

20

10

Phas

e ang

le (d

eg)

10minus1

Frequency (Hz)10

410

310

210

110

0

CeCCCeCC + H3BO3

(c)





Acknowledgments


References
































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





05 gL H3BO3


O 3074 1856Na 131 121Al 6681 7912Cl 077 110Ce 037Total 10000 10000

2500

2000

1500

1000

500

0

0 5 10

Cou

nts O

CeNa

Si Cl CeCeCu

Al

Energy (keV)





0

5000

10000

15000

20000


Pola

rizat

ion

resis

tanc

e (Ω

)





119901




O2

+ 2H2


H2

O2


O (2)

H2

O2





Element





O 192 1201 3025 684 326 1446 3247 712 009 1119 2693 597Na 009 095 1132 166 001 068 643 084 006 105 107 188Al 4033 8437 9754 924 1912 8494 962 1013 6653 8591 9938 638Si 003 132 4574 462 003 186 6512 674 001 034 273 031Cl 003 114 1143 192 003 083 758 100 005 133 1309 228Fe 003 018 141 015 008 018 14 016 005 018 056 009Ce 007 024 028 005 01 04 047 008 007 005 009 003

01051

minus1000

minus900

minus800

minus700

minus600

minus500

minus400

minus300

minus200

minus100

0


E(m

V ve

rsus

ECS

)

log |i|

(a)

0

5

10

15

20

25

30

35

01051

minus5


I(m

Ac

m2 )

E (mV)

(b)






119901


4 Conclusions



60000

40000

20000

0

0 20000 40000 60000

10000

5000

00 5000 10000

CeCCCeCC + H3BO3

|Z|

(Ω)

|Z| (Ω)

(a)

105

104

103

102

101

100

10minus1

Frequency (Hz)10

410

310

210

110

0

CeCCCeCC + H3BO3

|Z|

(Ω)

(b)

90

80

70

60

50

40

30

20

10

Phas

e ang

le (d

eg)

10minus1

Frequency (Hz)10

410

310

210

110

0

CeCCCeCC + H3BO3

(c)





Acknowledgments


References
































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





Element





O 192 1201 3025 684 326 1446 3247 712 009 1119 2693 597Na 009 095 1132 166 001 068 643 084 006 105 107 188Al 4033 8437 9754 924 1912 8494 962 1013 6653 8591 9938 638Si 003 132 4574 462 003 186 6512 674 001 034 273 031Cl 003 114 1143 192 003 083 758 100 005 133 1309 228Fe 003 018 141 015 008 018 14 016 005 018 056 009Ce 007 024 028 005 01 04 047 008 007 005 009 003

01051

minus1000

minus900

minus800

minus700

minus600

minus500

minus400

minus300

minus200

minus100

0


E(m

V ve

rsus

ECS

)

log |i|

(a)

0

5

10

15

20

25

30

35

01051

minus5


I(m

Ac

m2 )

E (mV)

(b)






119901


4 Conclusions



60000

40000

20000

0

0 20000 40000 60000

10000

5000

00 5000 10000

CeCCCeCC + H3BO3

|Z|

(Ω)

|Z| (Ω)

(a)

105

104

103

102

101

100

10minus1

Frequency (Hz)10

410

310

210

110

0

CeCCCeCC + H3BO3

|Z|

(Ω)

(b)

90

80

70

60

50

40

30

20

10

Phas

e ang

le (d

eg)

10minus1

Frequency (Hz)10

410

310

210

110

0

CeCCCeCC + H3BO3

(c)





Acknowledgments


References
































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




60000

40000

20000

0

0 20000 40000 60000

10000

5000

00 5000 10000

CeCCCeCC + H3BO3

|Z|

(Ω)

|Z| (Ω)

(a)

105

104

103

102

101

100

10minus1

Frequency (Hz)10

410

310

210

110

0

CeCCCeCC + H3BO3

|Z|

(Ω)

(b)

90

80

70

60

50

40

30

20

10

Phas

e ang

le (d

eg)

10minus1

Frequency (Hz)10

410

310

210

110

0

CeCCCeCC + H3BO3

(c)





Acknowledgments


References
































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



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