corrosion resistance nano-hybrid sol–gel coating on steel sheet

7/29/2019 Corrosion Resistance Nano-hybrid SolGel Coating on Steel Sheet

1/6

ISIJ Internat ional, Vol. 51 (2011), No. 3, pp. 435-440

Corrosion Resistance Nano-hybrid Sol-Gel Coating on SteelSheetAksh ya Kum ar GUIN, Suryaka nta NAYAK, Tapan Kum ar ROUT, Nikh i les BAN DYOPADH YAYand Di l l ip Kumar SENGUPTAR e s e a r c h a n d D e v e l o p m e n t , Ta t a S t e e l L t d . , J a m s h e d p u r 8 3 1 0 0 1 I n di a . E - ma i l : a k s h y a . g u i n @ t a t a s t e e l . c o m

(Received on May 26, 2010; accepted on December 3, 2010)

T i t a n i a - c o n t a i n i n g o r g a n i c - i n o r g a n i c h y b r i d s o l - g e l f i l m w a s d e v e l o p e d t o i mp r o v e t h e c o r r o s i o n resistancep r o p e r t y o f s t e e l . T i ta n i a p r e c u r s o r w a s p r e p a r e d f r o m t i t a n i u m- i s o p r o p o x i d e a n d me t h y l h y d r o g e n s i l i c o n ew a s u s e d a s a c o u p l i n g a g e n t t o e n h a n c e t h e a d h e s i o n a n d h y d r o p h o b i c n a t u r e o f c o a t i n g . Th e k i n e t i c s ,t h e r m a l r e s i s t a n c e a n d mo r p h o l o g y o f f i l m s w e r e a n a l y z e d b y , f o u r i e r t r a n s f o r me d i n f r a re d s p e c t r o s c o p y ,t h e r mo - g r a v i me t r i c a n d d i f f e r e n t i a l t h e r ma l a n a l y s i s a n d s c a n n i n g e l e c t r o n m i c r o s c o p y . Th e a n t i c o r r o s i o np e r f o r m a n c e o f t h e s o l - g e l c o a t e d s a m p l e w a s i n v e s t i g a t e d by e l e c t r o c h e m i c a l i m p e d a n c e s p e c t r o s c o p y .Th e r e s u l t s d e mo n s t r a t e d t h a t c o a t i n g s w e r e d e n s e , u n i f o r m a n d p r o v i d e d e x c e l l e n t c o r r o s i o n r e s i s t a n c ep r o p e r t i e s .K E Y W O R D S : s o l - g e l ; c o r r o s io n ; c o a t i n g s ; p o l y m e r ; E IS .

1. IntroductionIn recent years, organic-inorganic hybrid materials, due

to their enhanced coating properties, such as; resistance toscratching and abrasion, thermal stability, corrosion resist-ance, etc., have attracted considerable attention for re-search. The sol-gel route is the most commonly employedmethod for the preparation of organic-inorganic hybrids atmacro/micro-scale. Various organo metal precursors basedon silicone, titanium, aluminium, and zirconium have beenused in sol-gel process for synthesis of the inorganicp a r t . " '

The hybrid materials combine some advantages of or-ganic polymers (easy processing with conventional tech-niques, elasticity and organic functionalities) with proper-ties of inorganic oxides (hardness, thermal and chemicalstability, and transparency.7 ' Most of the organic-inorganichybrid materials reported in literature is thermally cured.8 '9 'Alternatively, hybrid network materials can be prepared bythe use of radiation curing an UV-curable binder sys-tem.10 '11 '

Nanostructure sol-gel coatings have been shown to pres-ent a promising alternative to the chromate-based surfacepretreatments.12 "16 ' Among them, organic- inorganic hybridcoatings are of special interest because they combine prop-erties of organic polymers and inorganic ceramics.10 '17- 20'Whereas the organic components allow tailoring of hy-drophobicity, flexibility, and functional compatibility withorganic paint systems; the inorganic components provide anincrease of scratch resistance, durability, and adhesion tothe metal substrate due to the formation of covalent Me-O-metal bonds. Moreover, incorporated inorganic nanoparti-cles can play the role of nano reservoirs for storage and

controllable release of the inhibitor species.11 '21 '22 'Performance of sol-gel coating, specifically adhesion

and barrier properties can be enhanced by incorporatingdifferent silane groups. It has been extensively demon-strated that organosilane offers effective corrosion protec-tion on metal.23- 25 '

In the present work, we focus on the preparation of stabletitania precursor from titania iso-propoxide and s ol-g elcoatings using titania precursor and methyl hydrogen sili-cone. We analyse the different performance like flexibility,thermal behaviour, and corrosion resistance properties etc.

2. Experiment2.1. Prepara tion of Sol -G el Solution

Titanium alkoxide, due to the presence of electronegativealkoxy groups is very reactive toward water and make pos-sible for a nucleophilic attack. Therefore titanium alkoxideneeds to be complexed with a chelating agent such as acetylacetone (AcAc), methacrylic acid (MA) etc. to control therate of hydrolysis.26 ' The titania sol was prepared from eth-ylene glycol monomethyl ether (EGME, Merck SpecialitiesPvt. Ltd.), titanium(IV) isopropoxide (Ti, 97% Aldrich) andacetyl acetone (AA, Merck Specialities Pvt. Ltd.). Five mil-liliters of titanium(IV) isopropoxide was mixed with 65 mLof EGME. The mixture was vigorously stir red (600-800rpm ) at 60C. Then 30 mL of AcAc was add ed slowly intothe solution. After addition of all the chemicals the sol wasstirred for next 60-90 mint for getting a complete homoge-neous solution as outlined by Rout et al. and other.27 "30 'Afte r 24 h of aging methyl hyd rogen silicone (Shin-EtsuChemical Co. Ltd.) was added slowly into the titania pre-cursor in a 1:1 volume/volume ratio at room temperature.

43 5 2011 ISIJ
mailto:[email protected]:[email protected]


2/6

iSIJ Internat ional, Vol. 51 (2011), No. 3

2.2. Applicat ion of Sol-G el CoatingsThe cold rolled and annealed (CRCA) steel sheets were

used for the present study. These sheets were cleaned to re-move oil and grease and subjected to phosphating in tri-cationic phosphate base solution to obtain a thin coating of< 0 . 5 jim thickness (2- 3 g/m2). The synthesized sol-gel so-lution was applied on bare CRCA and phosphated sheet bydipping process for 1 min at room temperature, followed byslow drying at the rate of 20C/m and finally kept at 150Cfor one 1 h2.3. Measurements

Spectra of sol-gel solution was recorded on fourier trans-form infrared spectrophotometer (Nicolet 5700, ThermoElectron Corporation) in the spectra range of 400 4000c m - 1 .

Particle size of sol-gel solution was determined by usingthe dynamic light scattering (DLS) technique (MalvernNano-ZS instrument) .

An advancing sessile drop method was used for thecontact angle measurement. The static contact angle ofcoated samples were determined by contact angle systemOCAH230 (Dataphysics Instrument, Germany). Deminer-alised water (DM) water is used as testing liquid.

Glass transition temperature (T) was calculated throughDifferential Scanning Calorimetry (DSC) study (TA instru-ment, Q10). Approximately lOmg of 7d cured film wastaken on hermitic type pans and immediately DSC runswere made at heating rates of 10C/min betwe en 30 500Cunder 50 mL /min nitrogen in a dynamic mo de of operation.The glass transition temperature was determined from thesecond heating cycle.

After curing for 7d, powdered sol-gel sample wasanalysed using a simultaneous TG-DTA analyser (Shi-madzu, DTG-60, Japan) in nitrogen environment with sam-ple weight of about 3 mg. Heating rate was maintained at10C/min in the temperature range of 30 to 500C.

The microstructure and surface morphology of thesol-gel coated sample were observed by a scanning elec-tron microscope (SEM, SUPRA 25, ZEISS FEG) equippedwith energy-dispersive spectrometer (EDX). The energyused for analysis was 15 kV

The cupping test was done as per the ASTM E643-84.The objective of this test is to identify the resistance of thecoated film against ongoing deformation of a coated steelpanel. Initial disturbance point (crack) measured in mm isrecoded as cupping value.

Corrosion resistance of sample was evaluated by electro-chemical impedance spectroscopy (EIS) and potentiody-namic polarisation techniques. The EIS measurements werecarried out using the Gamry EIS 300. A typical three elec-trode was employed in those tests, the samples acted asthe w orking electrode (1 cm 2 of exposed area), saturatedcalomel electrode (SCE) as reference and graphite ascounter electrode. 3.5% (w/v%) NaCl solution was used asan electrolyte in all the measurement. The EIS measure-men t was carried out in the frequency range of 100 kHz to0.01 Hz and the applied voltage was 5 m Y

Salt spray tests were carried out by exposing the un-scribed samples (7.5cmX7.5cm size coated panel with

5 - 6 jim dry film thickness) in a salt spray chamber as perthe ASTM B-l 17 test method. The panels were checked atregular interval of time and results were noted down interms of blisters, creep and red rust.

3. Result and Discussio n3.1. Infra Red Spectroscopy Study

The probable reaction between titania precursor and cou-pling agent methyl hydrogen silicone is outlined in Fig. 1.

The infra red spectra measured for the titania sol, methylhydrogen silicone silane and titania sol modified withmethyl hydrogen silicone silane are analysed. A shifting inthe wave number of the peaks and the presence of new peakare the indications of the breakage of existing bond and for-mation of new bonds. Infra red spectra of titania sol, asshown in Fig. 2 shows the presence of a sharp absorptionpeak at 3 400 cm 1, this indicates abou t the presence ofO-H stretching bond, which may be formed af ter thehydrolysis of titanium isopropoxide by ethylene glycolmono methyl ether. Intensity of O -H stretching peak at3 400 cm" 1 in Ti-sol has not appeared after reacting withsilane group which indicates about the reaction of Ti-solwith AC Ac and silane compound .31 ' The presence ofS i-O -Si band at 1000 to 120 0 cm" 1 indicates about the hy-drolysis of triethoxy group forming sinalol group and thesubsequent condensation gives rise to a very stable siloxanebond (Si-O-Si) . The presence of broad bands correspon-ding to Ti O Si at 930 cm " 1 indicates about the interactionof Ti-sol or its complex and its comp lex with silane gro up.

H,C- CH,CH,

CH, OHD-fa-O^j-SiCH 3 + HOTi-OHCH, CH,

M e t h y l H y d r o g e n P o l y s i l o x a n e

CH,

OHT i - S o l

CH,OTi O-^Si0-^Si CH3 + H3C Si OHI MO CH CH, CH,

Fig. 1. Probable reaction mech anism of Ti-sol and couplingagent.

T i S o l

So l+methy! hydrogenpoiysi loxane

M e t h y l h y d r o g e n p o l y s i l o x a n e

2500Wavenumbers (cm-1)

Fig. 2. FTI R study of Ti-precursor, coupling agent and sol -solution.

2011 ISIJ 43 6


3/6

ISIJ Internat ional, Vol. 51 (2011), No.3,pp .435-440

3.2. Particle Size Analy sisThe formulated sol gel solution is kept for 30 d to ob-

serve any precipitation or gelling, but no gelling has beennoticed even after 30 d of aging. Particle size distribution of30 d aged sol-gel solution has been measured. It is foundthat particle size is in the range of 2 - 5 nm as shown in Fig.3. This close size range is due to the controlled growth ofthe particles in the sol during hydrolysis and the condensa-tion reaction of titania precursor in the presence of waterand acetyl acetone (AcAc).32 ' The addition of AcAc mighthave inhibited both hydrolysis and condensation reaction oftitanium precursor.3.3. Therm al Analysis Study

The TG-DTA curve of the cured sample as shown in Fig.4 demonstrates very small weight loss in the temperaturerange of 150-200C which are characteristic of the desorp-tion of physically adsorbed water molecules. There is asteady weight loss between 150 an d 450C and oneexothermic peak is observed at 360C, (Fig. 4), which canbe attributed to the release of chemically bounded water(around 200C) and the decomposition of the organic com-ponents (around 300C). DTA curve demonstrates anexothermic peak near 400C, which can be associated withthe crystallization process of an amorphous oxide. 33 )

Afte r 700C only 27.80% weight loss has observedwhich implies about rigid and integrated polymer networkformed by titania and coupling agents. One of the impor-tant observations from TGA-DTA analysis is the slow andgradual degradation of polymer hybrid and there is no sud-

Size Distribution by Volume

S i z s| Record 15: KF|

Fig. 3. Particle size distribution curve of sol-gel solution.

den decomposition of coating which could provide crackfree surface to the applied coating even at higher tempera-ture. This is not the case in general organic paints and coat-ings.

The glass transition temperature determined from thesecond heating cycle is found to be 72.61C. This highglass transition temperature of cured coating, as shown inFig. 5 indicates about high rigidity and integral cross link-ing network formed by titania and silane group. This inte-gral cross linking network may create an environment formoisture and other aggressive anions which can not easilypenetrate through coating and subsequently enhance thecorrosion resistance of coated metal surface.3.4. Contact Angle Measurement

The evaluation of the wetting properties, estimation offree surface energy, and hydrophobicity of the non coatedand coated sample have been assessed by contact anglemeasurement. By applying following concept we can meas-ured the surface energy of coated sample from the calcu-lated contact angle.

The calculation of solid surface tension, y sv , from thecontact angle, 8, of a liquid of surface tension y Lv statewith Young's equationysL=7sv-7LvCOS0 (1)

Where y SL is the solid liquid interfacial tension.On the other hand, contact angle data clearly support theEquation of state (EOS) approach; where by the solid liquidinterfacial tension is thought to be a function only of thetotal solid and liquid surface tension irrespective of thetypes and relative magnitudes of the intermolecular forcespresent within each phase.

7 S L = / ( 7 L V > 7 S V ) ( 2 )

If the commonly used assumption of negligible liquid vaporadsorption is applied, then Eqs. (1) and (2) may be writtenin term of y L and y sAn old equation of state for solid-liquid interfacial ten-sion is that

7 s L = 7 s + 7 L - 2 ( 7 s y L ) 1 / 2 (3)Combining Eqs. (1) and (3) gives

7 S = 1/4/^(1 +co s 0)2


4/6

iSIJ Interna t ional , Vol . 51 (2011) , No. 3

Contact angle of the coat ings on phosphated sheet isfound to be 100.96 and corresponding surface free energymeasure d by E OS m ethod is found to be 22.45 mN /m(Table 1). Similarly contact angle of coating applied onCRCA sheet is found to be 98.9 and corresponding freesurface energy is 23.73, which means , both the coated sam-ples (phosphated and CRCA) impart hydrophobici ty on themetal surface. As the water molecules do not retain on thesurface due to this hydrophobicity, corrosion is also inhib-i ted on coated metal surfaces .3 .5 . Coat ing Morp hology Study

The surface composi t ion and morphology of the coat ingwas determined with SEM/EDX using a Leo ScanningElectron Microscope (SEM) with an EDAX EDX-systemfor chemical analysis. Au was sputtered to suppress charg-ing. The basic coating contains C, O, Si, and Ti along withFe peaks . Al though the EDX spectra don' t supply informa-tion about chemical state of these elements we can expectthat Si and Ti are present as oxides and the C is from the or-ganic sys tem. Oxygen is usual ly also present in organicpolymers as hydroxyl (-OH) groups or oxides from metals .We can detect C peaks in our current EDX system at highervol tage.

I t can be observed from SEM images (Fig. 6) that coat-ing is uniform w ithout any vis ible crack and there is no ag-glomerat ion of nano Ti and Si-part ic les in the polymer ma-trix films. EDX analysis of the coated sample shows that Ti

Table 1. Contact angle (C.A.) and surface free energy meas-urement .

C oat ingappl ied on

C . A .(Lef t )[ D ag]

C . A .(Middle)[Deg]

C.A. (Right)[ D eg]

Surface FreeEnergy [mN/m], byequat ion o fs t a t e(EOS) Met hod

Phos phat eds heet

101.0 101.0 100.9 -22.45

C R C A Sheet 98.8 98.9 99. 0 -23. 73U nc oat edC R C A s heet

21.5 21 21.5 -42.5

and Si and their Oxide completely covered the metal sur-face. These types of compact arrangement of part ic les re-sist nucleation and extension of micro cracks, resulting inbet ter surface coverage, s t rength and toughness . The thick-ness of the films was estimated by the cross-section analy-si s (Fig. 7) and is about 5-6 jum.3.6. Corro sion Perform ance Study3.6.1. Sal t Spray Study (AST M B-l 17)

Salt spray result indicates about the good corrosion re-s is tance of metal sample coated w ith ti tania sol-gel coat ingwhich may be due to the three diment ional network of poly-condensat ion of Ti(OH)4 and s i lane group and adherence tothe metal substrate through hydrogen bond between func-t ional ise ti tania and metal substrate immediately after appl i -cat ion. These bonds can be t ransform ed into s table covalentbond during the baking and curing process . 13 ' Even after400 h exposure t ime in AS TM B117 salt spray chamber(saline environment) there is no trace of blister formationon phosphated s teel sheet , (Fig 8, Table 2). Aft er 168 h ofexposure t ime CRCA panel has developed medium s izeblister which is con verted to de nse blister aft er 200 h. T his

Sol-gel Coating Phosphate

S t eel

Fig. 7. Depth profile study of coated sample by SEM -ED X.

i f

Bare CRCA- 2Hr Ti-sol gel- 400 Hr Ti-sol gel - 450 Hr

Fig. 8. Corrosion resistance study of coated samples in salt spraychamber.

Table 2. ASTM B117 sal t spray test data (M-medium, D-Danced).

Sur f ac e Ex pos ed T ime, hr24 48 72 100 144 168 20 0 40 0

C R C ABlister 10 10 10 10 10 8-M 8-D

C R C A Red Rust 10 10 10 10 8-F 8 -M 8- D

Phos phat ed

Blister 10 10 10 10 10 10 10 9- FPhos phat ed Red Rust 10 10 10 10 10 10 10 8 -M

2011 ISIJ 43 8


5/6

ISIJ Internat ional, Vol. 51 (2011), No.3,pp .435-440

Fig. 9. SEM -ED X .study of coated sample (after 400 h salt sprayexposure).

coating shows good barrier and corrosion resistance proper-ties (400 h for phosphated and 168 h for CRCA coated sam -ple) as against bare CRCA sheet which corrodes after only2h of exposure. The higher salt spray resistance of thedeveloped coating may be due to the formation of strongcovalent bonds between polymer molecule and metallicsurface. 34 ' It is believed that well condensed net work willgenerate high cross linking density. Water molecule cannot easily penetrate the highly cross linking network, andhelp to increase the corrosion resistance properties of the

2.00 3.00Log Freq (Hz)

Fig. 10. EIS study of phosphated coated sample at different t imeinterval.

-1.00 0.00 1.00 2.00 3.00 4.00 5.00 6.00Log Freq (Hz)

Fig. 11. EIS study of CR CA coated s ample at different t ime in-terval.

coating.Afte r 450 h of exposure in ASTM B 117 sample show s

red rust particle accumulated in some areas of the titaniacoated su rface with the creep diam eter less than 2 mm andthe peripherial coated area had good intact with metal sub-strate, composition of this red rust particles were analysedby SEM-EDX., from the EDX spectrum, as shown in Fig.9, it has been observed that these red rust particles are com -posed of Fe, Si, O, CI and Na. This confirms that nano tita-nia coating provides a good barrier property and even after400 h of ex pose in salt spray ch amber there is no free Ti-particle found in blister and rusted area (no breaking ofTi-O-Meta l bond)3.6.2. EIS Study

To assess the anticorrosive properties of the sol-gelfilms, immersion tests in 3.5% (w/v%) NaCl solution wereperformed. The corrosion behaviour of the coated sub-strates was studied by the EIS method. The typical impen-dence spectra of the samples coated with titania-containinghybrid films afte r different interval of time are p resented inFig. 10. One well defined time constants can be observedon the bode plots after 1-d imm ersion. The high frequencytime constant is resulted from the capacitance of the sol-gellayer. After several days of immersion an additional timeconstant appears on the impedance spectrum in the low fre-quency region due to the started corrosion attack (Fig. 10an d Fig. 11).

The numerical fittings using the appropriate equivalentcircuits were used in order to estimate the evolution of cor-rosion protection properties for different coatings understudy. The Randal equivalent circuits were selected for fit-ting the experimental results basing on the physico-chemi-cal model of the corrosion process. The hybrid coatingsdemonstrate the highest resistance, R coat, at the beginn ing of

43 9 2011 ISIJ


6/6

iSIJ Interna t ional , Vo l . 51 (2011), No. 3Taffel Study of Coaled Sample 4. Conclusion

-CRCA-lnitial-Coated-400 Hrs-Coated-initial

Log Current Density (A/cm2)

Fig. 12. Taffel polarisation study of coated sample.

immersion. However, this resistance decreases rapidly dur-ing the first 24 h of contact w ith chlorid e solution . Pen etra-tion of water molecules and chloride ions through the finestpores of the film is most probably responsible for this re-sistance drop. Characteristically, the initial coating resist-ance is significantly higher for coatings applied on phos-phated sheet as compared with coat ing appl ied on CRCAsheet, and the following drop in R a m t i s higher with coat ingappl ied on CRCA sheet . The appearance of second t imeconstant in the ini t ia l plot for CRCA coated sheet can beascribed to the presence of intermediate oxide film at themetal /coat ing interface. After several days of immersion(360 h), due to the o nset of corros ion at tack on CRC Acoated sheet an additional time constant appears in the lowfrequency region on the impedance spectrum . Coat ings ap-pl ied on phosphated sys tems have almost two orders ofmag ni tude difference in the ini t ia l R clrd[. However, even after672 h of imm ersion, the res is tance in phosph ated coatedsample is higher than that of initial coating resistance ofCR CA coated sample. I t should be noted that af ter 120 h ofimmersion, CRCA coated sample demonstrates the separa-tion of the high frequency time constant by two parts. Thiseffect may be associated with the form at ion of two layers inthe coat ing during the immersion: a more defect ive outerlayer (first t ime constant) and a dense inner layer (secondtime constant). Taking into the account the presence of twolayers, the fitting results show that the capacitance of thefirst layer is 30 times lower than the second one, which sup-ports an assumption of the separation of sol-gel film thissmall change in imp edance v alue is poss ible due to the highcross l inking densi ty (high Tg) of the polymer net workformed by nano t i tania-hybrid coat ing and also due to thehydrophobic surface of the coat ing, therefore water mole-cules or any other corros ive ingredient do not penetratethrough the surface of the coat ings . This provides a goodbarrier property.35 '36 '

Figure 12 shows the typical resul ts of pol tent iodynamicpolarisat ion curves of Ti-coated sample, Ti-coated sampleafter 40 0h ex pose in 3.5% (w/v% ) NaCl solut ion and bareCRCA sheet . Al l the measurements were carried out in3.5% (w/v%) NaCl solut ion in ai r a t room temperature.Even after 360h of exposure in 3.5% (w/v%) NaCl solu-t ion, Ti-coated sample shows less corros ion current thanbare substrate . This is due to very good barrier propert iesof the coating. This corrosion resistance property is sup-ported by high contact angle, low free surface energy, andhigh T value.

As indicated by salt spray test, corrosion resistance en-hanced from about 2 h to 168^100 h by nano s t ructuralsol-gel coat ing is due to the barrier developed between thesubstrate and corros ive medium. The surface coverage bythe nano part ic les (2- 5 nm) form ed by control l ing thegrowth during hydrolys is and condensat ion appears to bemore or less uniform. The coat ing adhesion to the surfacemay be due to the format ion of covalent bonds between thepolymer molecules and metal surface.A c k n o w l e d g e m e n t

Authors would l ike to thank the Director RD & T, TataSteel Limited for permiss ion and encouragement to carryout this work and also acknowledge the valuable support ofMr. A. K. Singh provided during this work.

REFERENCES1) C. J. Brinker and G. W. Sherer: Sol-G el Science, The Principle and

Chemistry of Sol-Gel Processing, Academic Press, New York,(1989).

2) T. Ogoshi and Y. Chujo: Compos.Interfaces, II (2005), 539.3) C. H. Landy and B. K. Coltrain: Polymer, 33 (1992), 1486.4) A .B. Brennan and G. L. Wilkes: Polymer, 32 (1991), 733.5) Y. Tong and Y. Liu: J. Appl. Polym. Sci., 83 (2002), 1810.6) J. Gilberts and A. H. A. Tinnemas: J. Sol-Gel Sci. Technol., 11

(1998), 153.7) C. Sanchez and B. Jullian: J. Mater. Chem., 15 (2005), 3559.8) P. Judeinstein and C. Sanchez: J. Mater. Chem ., 6 (1996), 511.9) Y. Wei and R. Bakthavatehalam: Chem. Mater., 2 (1990), 337.

10) M. E. L Wouters and D. P. Wolfs: Prog. Org. Coat., 51 (2004), 312.11) G. Bayramoglu and M. V Kahraman: Prog. Org. Coat., 57 (2006),

50 .12) R. L. Twite and G. P. Bierwage n: Prog. Org. Coat., 33 (1998), No. 2,91 .

13) M. L. Zheludkevich : J. Mater. Chem., 15 (2005), 5099.14) T. L. Metroke and R. L. Parkhill: Prog. Org. Coat., 4 1 (2001), No. 4,

233.15) M. Khobaib and L. B. Reynolds: Surf. Coat. Technol., 14 0 (2001),

No. 1, 16.16) M. S. Donley and R. AM antz: Prog. Org. Coat., 41 (2001), No. 4,

233.17) Y. J. Du, M. Damron and G. Tang: Prog. Org. Coat, 47 (2003), 401.18) C. Sanchez and G. J. De: Chem. Mater., 13 (2001), 3061.19) S. Hofa ccker and M. Mech tel: Prog. Org. Coat., 45 (2002), 159.20) M. L. Zheludkevich and R. Serra: Acta, 51 (2005), 208.21) M. L. Zheludkev ich and R. Serra: Electrochem. Commun., 7 (2005),

836.22) M. L. Zheludkevich and R. Serra: Surf. Coat. Technol, 20 0 (2006),3084.

23) M. L. Zheludkevich : J. Mater. Chem., 15 (2005), 5099.24) T. P. Cho u: J. Sol-Gel Sci. Technol., 26 (2003), 321.25) T. Metroke: J. Sol-Gel Sci. Technol., 51 (2009), 23.26) T. Lu: Powder Technol., 18 8 (2009), 264.27) . R. Dholam: Int. J. Hydrogen Energy, 33 (2008), 6896.28) J. L. H. Chau and C.-t . Tung: Mater. Lett., 62 (2008), 3416.29) T. K. Rout: Scr. Mater., 58 (2008), 473.30) P. D. Mo ran and C. E. F. Rickard: Inorg. Chem., 37 (1998), 1414.31) J. Franc and D. B. Lane: Mater. Sci. Eng. B, 12 9 (2006), 180.32) M .D. Hernan dez-A lonso and I. Tejedor: Thin Solid Films, 50 2

(2006), 125.33) S. I. Seok: Surf. Coat. Technol., 20 0 (2006), 3468.34) Y. Zhu and C. Ding: J. Euro. Ceram. Soc., 20 (2000), 127.35) T. K Rout: Scr. Mater., 56 (2007), 573.36) T. Valente and F. P. Galliano: Surf. Coat. Technol., 12 7 (2000), 86.

2011 ISIJ 44 0

corrosion resistance nano-hybrid sol–gel coating on steel sheet

Documents