3. the effect of saccharin addition and bath temperature on the grain size of nanocrystalline nickel...

8/10/2019 3. the Effect of Saccharin Addition and Bath Temperature on the Grain Size of Nanocrystalline Nickel Coatings (6 P

1/6

The effect of saccharin addition and bath temperature on the grain size ofnanocrystalline nickel coatings

A.M. Rashidi a,b, A. Amadeh b,a School of Engineering, Razi University, P.O. Box 67149-67346, Kermanshah, Iranb School of Metallurgy & Materials Engineering, University College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran, Iran

a b s t r a c ta r t i c l e i n f o

Article history:

Received 8 June 2008Accepted in revised form 28 July 2009Available online 6 August 2009

Keywords:

Bath temperatureElectroplatingGrain sizeNanocrystalline nickelSaccharinTheoretical model

Nanocrystalline nickel coating was synthesized by direct current electrodeposition from a Watts bath at thecurrent density of 100 mA/cm2 and pH=4. The effect of saccharin addition (010 g/l) and bath temperature(4565 C) on the average grain size of the deposits was investigated by XRD technique. The results showedthat the average grain size decreased from 426 nm to 25 nm as the saccharin concentration increased from 0to 3 g/l, while further increase in saccharin concentration had no signicant effect. Theoretical model alsoindicated a non-linear function for dependence of grain size on saccharin concentration, which was inaccordance with experimental results. The experimental results showed that the increases in the bathtemperature had no considerable effect on the average grain size of the deposits. A theoretical formula wasalso established for the temperature dependence of the grain size.

2009 Elsevier B.V. All rights reserved.

1. Introduction

Electrodeposition has received considerable attention in recentyears as a feasible and economically viable technique for producingnanocrystalline coatings[15]. This process is a powerful method forfabrication of many highly precise products and synthesizing metallicnanomaterials with controlled shape and size [6]. However, theperformance of electrodeposition for application of nanocrystallinecoatings is actually related to electroplating conditions and thecomposition of plating bath. It has been demonstrated[710]thatunder certain suitable conditions, only electrodeposition can, indeed,yield the production of nanocrystalline nickel coatings. So, importancehas been gradually attached to study in this eld in recent years.

The impressibility of microstructure of nickel electrodeposits fromelectrodeposition process parameters such as electrolyte type [9],deposition technique (direct or pulse plating) [1114], pulse para-meters [2,3,7,1417] and types of waveform in pulse currentelectroforming[18], applied current density in direct current electro-plating [5,911,19,20], pH of electrolyte [21,22], substrate condi-tions[9,23], addition of micro and nano-sized particles to the bath[2436], emulsion electroplating with dense CO2[37], the presence,concentration, and combined effect of additives such as saccharin, 2-

butyne-1,4-diol, etc. [8,10,12,15,38,39], and the rotation speed ofcylindrical electrode[40]have already been investigated. Neverthe-less, the results of electroplating experiments obtained by differentresearchers are difcult to optimize certain conditions for productionnanocrystalline nickel coating, because in some cases, the reporteddata are inconsistent or even different. For instance, Pin-Qiang et al.[10] found that the grain size of nickel deposits decreased from 50 nmto about 20 nm by increasing the current density from 50 mA/cm2 to100 mA/cm2 while the effect of current densities higher than100 mA/cm2 was negligible. Unlike to these results, a continuousincreasing in the grain size versus current density has also beenrecognized in direct current electrodeposition of nickel coating[5,9,11,17]. On the other hand, Aruna et al. [19]reported that thecurrent density had no signicant effect on the grain size of nickelelectrodeposits.

A review of literatures shows that saccharin has often been addedto nickel plating bath from the 80s [41] in order to improve theductility, brightness, and at later periods as a grain rener agent. Thegrain rening by increasing the saccharin concentration in Ni platingbath was investigated by Erb et al. [8], Pin-Qianget al. [10] and Xuetaoet al.[16]. Although the addition of saccharin decreased the grain sizeof the coating, but the saccharin content corresponding to leveling offin grain size reduction with increasing the saccharin concentration isdifferent in these references. Furthermore, in earlier studies[8,10,15,16]there is still a lack of simple and general mathematicalequations for dependence of the grain size of deposit on saccharinconcentration. The quantitative relationships can assist in reducing

Surface & Coatings Technology 204 (2009) 353358

Corresponding author. Tel.: +98 21 66493046; fax: +98 21 66480290.E-mail addresses:[email protected](A.M. Rashidi),[email protected]

(A. Amadeh).

0257-8972/$ see front matter 2009 Elsevier B.V. All rights reserved.

doi:10.1016/j.surfcoat.2009.07.036

Contents lists available at ScienceDirect

Surface & Coatings Technology

j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / s u r f c o a t
mailto:[email protected]:[email protected]://dx.doi.org/10.1016/j.surfcoat.2009.07.036http://www.sciencedirect.com/science/journal/02578972http://www.sciencedirect.com/science/journal/02578972http://dx.doi.org/10.1016/j.surfcoat.2009.07.036mailto:[email protected]:[email protected]


2/6


3/6


4/6

whereks= kin is constant. All constant parameters in Eq. (8) can bederived experimentally by curve tting. The numerical relationshipsobtained by non-linear curve tting with Matlab software are:

d= 24:1 + 2000C7s

0:149

d= 15:1 + 2000C7s

0:0910

forthe present experimental results and thedata reportedby Erbet al.[8,15], respectively. In Fig. 3, the experimental data has also beencompared with mathematical curve computed from Eqs. (9) and (10).It is evident that the theoretical model is consistent with both thepresent experimental results and the data reported in [8,15] forelectrodeposition of nickel coating. The model (Eq. (8)) was alsochecked by curve tting for the data reported by Natter andHempelmann [44] who used butanediamine additive for golddeposition and benzoic acid additive for aluminum deposition. Theresults were presented in Fig. 4. Good agreement between theirexperimental results and our theoretical model is evident in thisgure indicating that the general model is also applicable for otheradditives used in electroplating of other metallic coatings.

3.2. Effect of bath temperature

3.2.1. Experimental results

It hasbeen demonstrated [20] that the plot of normalized intensity(IN,hkl= Ihkl/ Ip,hkl) of each reecting planes versus diffraction angle

(2) presents a better perspective of XRD peak broadening. For thisreason, the normalized intensity of (111) reection for nickel coatingsdeposited at various bath temperatures as well as the referencesample (annealed nickel) were presented inFig. 5. It is qualitativelyclear that the peak width increases by increasing the bath temper-ature from 45 C to 55 C (Fig. 5a), but further increase in the bathtemperature decreases the peak width (Fig. 5b). Based on the changein peak width, it seems that the grain size of deposits reduces as the

plating temperature increases up to 55 C and then increases byfurther increase in the bath temperature.The quantitative variation of the average grain size of the coatings

versus bath temperature has been shown in Fig. 6a. This gureindicates that nanostructured nickel deposits with a mean grain sizebetween 24 nm and 32 nm can be obtained at all the investigatedtemperatures. It is also evident that the bath temperature has a minoreffect on the average grain size of the coatings with respect to currentdensity (Fig. 3 of Ref. [20]) and saccharinaddition (Fig. 3). Meanwhile,considering the error bars of the measurements, it can be observedthat the variation of plating temperature does not have a considerableinuence on the mean grain size of deposits.

3.3.2. Theoretical approach

According to the pattern presented by Dini[66,71],it is generallyexpected that the grain size of thedepositsincreases by increasing thebath temperature and has been experimentally observed for somenanocrystalline deposits[4244].

The general effect of bath temperature on the grain size of thedeposits arises from the dependence of cathodic overpotential onplating temperature. As shown by Volmer and Weber [72], the energyof grain nucleus formation depends on the cathodic overpotential. Alarge cathodic overpotential reduces the energy of nucleus formation,and therefore increases the nucleus densities (the number of nucleuspersurface area) andrenes of coating grains. Consequently, since thecathodic overpotential decreases with increasing the bath tempera-ture[44,66], it is expected that the grain size of deposits will increase.Nevertheless, it should be noted that increasing the bath temperaturehas two contradictory effects; (i) an increase in critical size of nucleus

Fig. 4. Comparison of experimental data reported in [44] and theoretical model forvariation of the grain size of nanocrystalline, a) gold and b) aluminum deposits with

additive concentration.

Fig. 5. Normalized (111) reection peaks of ref. sample and nanocrystalline nickel

coatings deposited at (a) 45, 50 and 55 C and (b) 55, 60 and 65 C.

356 A.M. Rashidi, A. Amadeh / Surface & Coatings Technology 204 (2009) 353358


5/6

due to a decrease in the thermodynamic driving force of crystalliza-tion process which leads to lower nucleus densities, and (ii) anincrease in the kinetic driving force that can lead to higher nucleationrate [73]. At the bath temperaturesin which thesize of critical clustersis in atomic dimensions, every active site can act as a critical nucleus.So, the thermodynamic barriers for nucleus formation are negligibleand the grain size of deposit is controlled by kinetics variables.Therefore, in such conditions, according to Arrhenius equation, thenucleation rate increases by increasing the bath temperature[74]. Itseemsthat low dependence of the mean grain size of electrodepositednanocrystalline nickel on the bath temperature in the present work,canbe attributed to thebalance between thermodynamic barriers and

kinetics variables in investigated bath temperature range.Based on atomistic theory of electrocrystallization [7577], a

general formula can be derived to demonstrate the relationshipbetween the grain size and bath temperature. According to atomistictheory of electrocrystallization, the stationary nucleation rate (Ist) canbe expressed as[75]:

Ist= koexp kc

RT

exp

nc+ bzFRT

11

wherekoandkcare constants,Ris the ideal gas law constant (8.314 J/mol K),Tis the absolute temperature (K),ncis the number of atomsconstituting the critical nucleus,(V) is overpotential andb is equalto 1 or (the cathodic charge transfer coefcient) depending on the

mechanism of nucleus formation, z is the charge number of the

reaction, F is the Faraday's constant (96,500 As/mol). Here, forsimplicity, it is assumed that (i) all assumptions used for derivationof Eq. (11)[7577]are valid for electroplating processes, and (ii) inelectrodeposition, the cathodic current density is enough high. So, theTafel equation can be used:

= RT

zFln

i

io

12

where io (A/cm2) is the exchange current density. IntroducingEq. (12) into Eq. (11), it can be obtained:

Ist= koexp kc

RT

i

io

B

13

in whichB=nc+ b =. On the other hand, the experimental data[74,78] and theoretical modeling [79,80] have indicated that theexchange current density (io) is a function of temperature in thegeneral form of:

io= An exp Bn

RT

14

whereAnandBnare constant. Thus, Eq. (14) can be rewritten as:

Ist= koi

An

B

exp kcBBn

RT

15

From the other point of view, a general relationship between theaverage grain size of deposit (d) and the stationary nucleation rate(Ist) can be expressed as[20]:

d=kd

i

Ist

1=316

wherekdis constant. Finally, the combination of Eqs. (15) and (16)yields to:

d=kfexp

BkRT

17

in whichkf= kdABn

i1=3B andBk=

kcBBn3 .

Eq. (17) indicates that the increase in bath temperature, at a givencurrent density, may increase or decrease the grain size of depositsdepending on the sign ofBk. Assuming thatBkandkfare independentof bath temperature, the validity of Eq. (17) was checked by curvetting for our experimental data as well as the data reported in[44].The results were presented inFig. 6. As seen, the calculated curvesbased on Eq. (17) for nanosized grains are consistent with thereported experimental data[44]as well as with our ndings at theplating temperatures above 50 C, but at the temperatures below50 C a discrepancy was observed. The reasons of this discrepancy

could be as: The efcient current density enhances by increasing the bath

temperature[48]. This can be probably due to the lowering of (a)the passivation of cathode surface by precipitation of nickelhydroxide[46,8082], (b) evolution of hydrogen[5]and dissolu-tion of some nickel clusters [83] by increasing the bathtemperature.

The efcacy of saccharin additive improves by increasing the bathtemperature.

The nucleation processes are controlled by kinetic driving forcedue to atomic dimensions of critical clusters.

Therefore, Eq. (17) should be modied and more electrochemicalexperiments are still needed to reveal the explicit dependence of

nucleation rate and grain size of deposits on the bath temperature.

Fig. 6.Comparison of experimental results and theoretical model for variation of thegrain size of nanocrystalline, a) nickel (present work) and b) aluminum deposits [44]

with bath temperature.

357A.M. Rashidi, A. Amadeh / Surface & Coatings Technology 204 (2009) 353358


6/6

4. Conclusions

Analysis of the results led to the following conclusions:

1. Addition of saccharinto theelectroplatingbathreduced thegrainsizeof nanocrystalline nickel coatings up to a concentration of 3 g/l.Further increase in saccharin content had no signicant effect ongrain renement.

2. Theoretical approach predicted a non-linear dependence of the

grain size on saccharin concentration, which conrmed theexperimental results.

3. The bath temperature had no signicant effecton theaverage grainsize of nickel deposits.

4. Theoretical model predicted an exponential dependence of thegrain size of deposits on bath temperature, which conrmed by theexperimental results.

Acknowledgements

This research was supported by the University of Tehran and RaziUniversity. The authors would like to thank them fornancial supportof this work. Dr. S. F. Kashani-Bozorg is also thanked for his fruitfulhelp.

References

[1] S.C. Tjong, H. Chen, Mater. Sci. Eng. R 45 (2004) 1.[2] L. Wang, Y. Gao, T. Xu, Q. Xue, Mater. Chem. Phys. 99 (2006) 96.[3] N.S. Qu, D. Zhu, K.C. Chan, W.N. Lei, Surf. Coat. Technol. 168 (2003) 123.[4] U. Erb, Can. Metall. Q. 34 (1995) 272.[5] F. Ebrahimi, Z. Ahmed, J. Appl. Electrochem. 33 (2003) 733.[6] D. Bera, S.C. Kuiry, S. Seal, JOM 56 (2004) 49.[7] A.M. El-Sherik, U. Erb, J. Page, Surf. Coat. Technol. 88 (1996) 70.[8] A.M. El-Sherik, U. Erb, J. Mater. Sci. 30 (1995) 5743.[9] I. Bakony, E. Tth-Kdr, L. Pogny, Czirki, I. Gercs, K. Varga-Josepovits, B.

Arnold, K. Wetig, Surf. Coat. Technol. 78 (1996) 124.[10] D. Pin-Qiang, Y. Hui, L. Qiang, Trans. Mater. Heat Treatment 25 (2004) 1283.[11] I. Bakony, E. Tth-Kdr, T. Tarnczi, L.K. Varga, Czirki, I. Gercs, B. Fogarassy,

Nanostruct. Mater. 3 (1993) 155.[12] E.A. Pavlatou, M. Raptakis, N. Spyrellis, Surf. Coat. Technol. 201 (2007) 4571.[13] C. Kollia, N. Spyrellis, Surf. Coat. Technol. 37 (71) (1993) 7.

[14] E. Tth-Kdr, I. Bakonyi, L. Pogny, Czirki, Surf. Coat. Technol. 88 (1996) 57.[15] R.T.C. Choo, J. Toguri, A.M. El-Sherik, U. Erb, J. Appl. Electrochem. 25 (1995) 384.[16] Y. Xuetao, W. Yu, S. Dongbai, Y. Hongying, Surf. Coat. Technol. 202 (2008) 1895.[17] K.L. Morgan, Z. Ahmed, F. Ebrahimi, Mat. Res. Soc. Symp. Proce. 634 (2001)

B3.11.1, Materials Research Society.[18] K.P. Wong, K.C. Chan, T.M. Yue, J. Appl. Electrochem. 31 (2001) 25.[19] S.T. Aruna, S. Diwakar, A. Jain, K.S. Rajam, Surf. Eng. 21 (2005) 209.[20] A.M. Rashidi, A. Amadeh, Surf. Coat. Technol. 202 (2008) 3772.[21] C.A. Schuh, T.G. Nieh, T. Yamasaki, Scr. Mater. 46 (2002) 735.[22] F. Ebrahimi, G.R. Bourne, M.S. Kelly, T.E. Matthews, Nanostruct. Mater. 11 (1999)

343.[23] F. Ebrahimi, Z. Ahmed, Mater. Charact. 49 (2003) 373.[24] C.T.J. Low, R.G.A. Wills, F.C. Walsh, Surf. Coat. Technol. 201 (2006) 371.[25] A.F. Zimmerman, D.G. Clark, K.T. Aust, U. Erb, Mater. Lett. 52 (2002) 85.[26] A. Mller, H. Hahn, Nanostruct. Mater. 12 (1999) 259.[27] C.S. Lin, K.C. Huang, J. Appl. Electrochem. 34 (2004) 1013.[28] I. Naposzek-Bilnik, A. Budniok, B.osiewicz, L. Pajk, E.giewka, Thin Solid Films

474 (2005) 146.

[29] S.C. Wang, W.C.J. Wei, J. Mater. Res. 18 (2003) 1566.[30] A. Abdel Aal, M. Bahgat, M. Radwan, Surf. Coat. Technol. 201 (2006) 2910.[31] A. Robin, R.Q. Fratari, J. Appl. Electrochem. 37 (2007) 805.[32] J. Panek, A. Budniok, Surf. Coat. Technol. 201 (2007) 6478.[33] I.R. Aslanyan, J.-P. Bonino, J.-P. Celis, Surf. Coat. Technol. 200 (2006) 2909.[34] S.T. Aruna, K.S. Rajam, Scr. Mater. 48 (2003) 507.[35] M. Stroumbouli, P. Gyftou, E.A. Pavlatou, N. Spyrellis, Surf. Coat. Technol. 195

(2005) 325.[36] L. Chen, L. Wang, Z. Zeng, T. Xu, Surf. Coat. Technol. 201 (2006) 599.[37] H. Wakabayashi, N. Sato, M. Sone, Y. Takada, H. Yan, K. Abe, K. Mizumoto, S.

Ichihara, S. Miyata, Surf. Coat. Technol. 190 (2005) 200.

[38] E.M. Oliveira, G.A. Finazzi, I.A. Carlos, Surf. Coat. Technol. 200 (2006) 5978.[39] G. Georgiev, I. Kamenova, V. Georgieva, E. Kamenska, R. Hempelmann, H. Natter, J.Appl. Polym. Sci. 102 (2006) 2967.

[40] E. Moti, M.H. Shariat, M.E. Bahrololoom, Mater. Chem. Phys. 111 (2008) 469.[41] G.L. Flx, J.D. Pollack, Anal. Chem. 52 (1980) 1589.[42] H. Natter, R. Hempelmann, Electrochim. Acta 49 (2003) 51.[43] H. Natter, R. Hempelmann, J. Phys. Chem. 100 (1996) 19525.[44] H. Natter, R. Hempelmann, Z. Phys. Chem. 222 (2008) 319.[45] M. Paunovic, M. Schlesinger, Fundamentals of Electrochemical Deposition, Wiley-

Interscience Publication, John Wiley & Sons, Inc, 1998.[46] D.R. Turner, J. Electrochem. Soc. 100 (1953) 15.[47] O.O. Schaus, R.J. Gale, W.H. Gauvin, Plating 58 (1971) 801.[48] A.H. DuRose, Plat. Surf. Finish. 64 (1977) 48.[49] J. Amblard, I. Eplboin, M. Froment, G. Maurin, J. Appl. Electrochem. 9 (1979) 233.[50] M. Holm, T.J. O'Keefe, J. Appl. Electrochem. 30 (2000) 1125.[51] O. Aaboubi, J. Amblard, J.P. Chopart, A. Olivier, J. Phys. Chem. B 105 (2001) 7205.[52] A.A. Rasmussen, P. Mller, M.A.J. Somers, Surf. Coat. Technol. 200 (2006) 6037.[53] D. Mockute, G. Bernotiene, R. Vilkaite, Surf. Coat. Technol. 160 (2002) 152.[54] T. Ungr, J. Gubicza, G. Ribrik, A. Borbly, J. Appl. Crys. 34 (2001) 298.

[55] T. Ungr, I. Dragomir, . Rvsz, A. Borbly, J. Appl. Crys. 32 (1999) 992.[56] D.A. Vermilyea, J. Electrochem. Soc. 106 (1959) 66.[57] R. Weil, H.C. Cook, J. Electrochem. Soc. 109 (1962) 295.[58] T.C. Franklin, Surf. Coat. Technol. 30 (1987) 415.[59] L. Oniciu, L. Muresan, J. Appl. Electrochem. 2 1 (1991) 565.[60] J.P. Bonino, P. Pouderoux, C. Rossignol, A. Rousset, Plat. Surf. Finish. 79 (1992) 62.[61] T.C. Franklin, Plat. Surf. Finish. 84 (1994) 62.[62] D. Mockute, G. Bernotiene, Surf. Coat. Technol. 135 (2000) 42.[63] A. Ciszewski, S. Posluszny, G. Milczarek, M. Baraniak, Surf. Coat. Technol. 183

(2004) 127.[64] B. Szeptycka, Russ. J. Electrochem. 37 (2001) 684.[65] Y. Nakamura, N. Kaneko, M. Watanabe, H. Nezu, J. Appl. Electrochem. 24 (1994)

227.[66] J.W. Dini, Electrodeposition: The Material Science of Coatings and Substrates,

Noyes Publications, 1993.[67] W. Kim, R. Weil, Surf. Coat. Technol. 38 (1989) 289.[68] C.C. Roth, H. Leidheiser, J. Electrochem. Soc. 100 (1953) 553.[69] J. Edwards, Trans. Inst. Metal Fin. 41 (1964) 169.[70] I. Langmuir, J. Am. Ceram. Soc. 40 (1918) 1361.[71] J.W. Dini, Plat. Surf. Finish. 75 (1988) 11.[72] M. Volmer, A.Z. Weber, Die Kinetik der Phasenbildung, Steinkopff, Dresden, 1939.[73] J.W.P. Schmelzer, Mater. Phys. Mech. 6 (2003) 21.[74] J. Vazquez-Arenas, R. Cruz,L.H. Mendoza-Huizar, Electrochim. Acta52 (2006) 892.[75] A. Milchev, Electrocrystalization: Fundamentals of Nucleation and Growth,

Kluwer Academic Publishers, 2002.[76] A. Milchev, S. Stoyanov, R. Kaischew, Thin Solid Films 22 (1974) 267.[77] A. Milchev, S. Stoyanov, R. Kaischew, Thin Solid Films 22 (1974) 255.[78] L. Cifuentes, J. Simpson, Chem. Eng. Sci. 60 (2005) 4915.[79] A.J. Bard, L.R. Faulkner, Electrochemical Methods, Fundamentals and Applications,

John Wiley & Sons, Inc, 2001.[80] K.J. Vetter, Electrochemical Kinetics, Academic Press, New York, 1967.[81] F. Lantelme, A. Seghiouer, A. Derja, J. Appl. Electrochem. 28 (1998) 907.[82] A.G. Munoz, D.R. Salinas, J.B. Bessone, Thin Solid Films 429 (2003) 119.[83] P.V. Brande, A. Dumont, R. Winand, J. Appl. Electrochem. 24 (1994) 201.

358 A.M. Rashidi, A. Amadeh / Surface & Coatings Technology 204 (2009) 353358

3. the effect of saccharin addition and bath temperature on the grain size of nanocrystalline nickel...

Documents