Preparation of Hydroxyapatite Coatings on Enamel by Electrochemical Technique

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1 CHINESE JOURNAL OF INORGANIC CHEMISTRY Vol.25 No ~1193 1,2 *,1 1 ( 1, ) ( 2, ) : Ca(NO 3 ) 2 NH 4 H 2 PO 4 NaNO 3, (HA) X (XRD) (SEM) (EDS), ph (HA), HA c ph ma cm -2 55, HA c, HA : ; ; (HA); : O614 : A : (2009) Preparation of Hydroxyapatite Coatings on Enamel by Electrochemical Technique LIAO Ying-Min 1,2 FENG Zu-De *,1 LEI Cai-Xia 1 ( 1 Collage of Materials, Xiamen University, Xiamen, Fujian ) ( 2 Department of Environmental Science and Engineering, College of Tan Kah Kee, Xiamen University, Zhangzhou, Fujian ) Abstract: Hydroxyapatite (HA) coatings were successfully prepared on human enamel surfaces by electrochemical technique with the electrolyte of Ca(NO 3 ) 2, NH 4 H 2 PO 4 and NaNO 3. Their crystal structures were analyzed by X-ray powder diffraction (XRD). Also, their surface morphologies were investigated by scanning electron microscopy (SEM). In addition, the chemical composition of the coatings were analyzed by an energy dispersion spectroscopy (EDS) attached to SEM. The formation of the coating was studied with particular emphasis on the effects of the process parameters such as the initial ph values of the electrolyte, the current density, and the temperature. The results showed that the process parameters had no significant influence on the composition of the coatings, which was determined as HA. But the degree of preferential orientation of c-axis of HA was great influenced by them. The HA crystals preferentially grew along the c-axis when the initial ph was 6.00 at 55 with the current density of 0.5 ma cm -2. And the degree of preferential orientation implied a similar value to the natural enamel crystals. Key words: electrochemical technique; enamel; hydroxyapatite(ha); coatings,,,,,,,anderson [1], 0.1~0.5 μm, : : (No ), (No.WKJ ) * zdfeng@xmu.edu.cn,Tel: :,,29,, ; :

2 ,,, ;, [2,3], 1~10 μm, [4] ; (HA) [6], ( 1 h, 7 ph, d ),, [5], 121,202.6 kpa, HA, HA, ma cm -2, 1 h, 0.02~0.10 mol L ~0.2 mol L -1, Ca/P( ) 1.3,pH 4.0, 2.1 ph [13,14] 80 min,, 1 1~10 μm, (HA) 1.1 [6], HA,, [6] ph /,, 1 h, Vijayarayhavan mol L -1 Ca(NO 3 ) 2, mol L -1 Bensalem [7], α-ti, 55 NH 4 H 2 PO 4, 0.1 mol L -1 NaNO 3, ph, HA ; 6~12, 37~85, 25, 1998, 0.01~10 ma cm -2 Shirkhanzadeh [8] 1.2, -1.4 V, 85 X PertX ph ph,2 h (X pert PRO,Panalytical,Netherlands) [9~12] HA X :Cu Kα,λ= nm,40 kv,30 ma, 0.008, Ti s, 20 ~80 ; 6Al-4V,0.042 mol L , 0.2 mol L -1, ph (ESEM-TMP,XL30, 4.4, (25 ) Philips-FEI,Holland), 20.0 kv, (60 ) (EDS,Oxford INCA300,, ;, England), ; ( g),,, 2 1 2, : ph 6, i=0.5 ma

3 7 : 1189 cm h (004) 3(a) SEM EDS 1, 2 (Ca) (O) (P),EDS Ca/P 1.66, Ca/ P (1.67) ph 8,10 12, SEM, ph ; EDS Ca/P 1.67 XRD Fig.1 1 SEM SEM image of the coatings 3 Fig.3 ph XRD XRD patterns of the coatings formed at different initial ph values of electrolyte ph HA c, c I (002)R I (004)R (002) (004) (211) (112) (300), Fig.2 2 EDS EDS spectrum of the coatings ( ) XRD ( 3) HA, 3(b)~(e) XRD (002) I (002)R = I (211) +I (112) +I (300), P (004) = I (004)R-I s R I s R, ph HA c I (002) I (004) I (004)R = I (211) +I (112) +I (300) HA PDF No (002) (004) I s R =0.182 I s R =0.091; c : P (002) = I (002)R-I s R I s R 1, Table 1 1 ph HA c Effect of electrolyte s initial ph values on c-axis preferred orientation of HA coatings Sample I (002) I (004) I (211) I (112) I (300) I (002)R I (004)R P (002) P (004) Criterion I s R=0.182 I s R= Enamel ph= ph= ph= ph=

4 ph,p (002) P (004) XRD HA PDF No. (P (002) P (004) ), EDS ( 2) c, HA, (002) ph, ; HA ph 6, HA c HA, 5 HA, HA HA (002) c 3 2.2, 4 HA 0.5 ma cm -2,P (002) SEM 4(b)~(d) P (002) (5.593),,, 2 ma cm EDS,P (002), (002), Ca/P HA Ca/, P (1.67) 5 ( ph 6), 55, i=0.01 ma cm -2 i=0.05 ma cm -2 i=0.1 ma cm -2 i=0.5 ma cm -2 i=1 ma cm -2 i=2.5 ma cm -2 i=5 ma cm -2 i=10 ma cm -2,,HA (002) ; 2 ma cm -2, (002),P,,HA, SEM ( 4), 8, 1 h HA ( 6), (a) 0 ma cm -2, 48 h; (b) 0.5 ma cm -2, 1 h; (c) 2.5 ma cm -2, 1 h; (d) 10 ma cm -2, 1 h Fig.4 4 HA SEM SEM images of the HA coatings formed at different current density

5 7 : Table 2 HA EDS analysis of the HA coatings formed at different current density Current density / (ma cm -2 ) Element At / % Ca/P 0 Ca K P K Ca K P K Ca K P K Ca K P K XRD, HA Fig.5 XRD patterns of the coatings formed at different current density 9 d(216 h) [15] Busch [16], ( ),,, 500 nm, 1 h 2 6 Fig.6 Effect of current density on the HA coating,ca PO 4 amount (kg m -2 ) μm HA [6], 2 d, 1 h ( 4(a) 4(b)) HA Table 3 3 HA c Effect of current density on c-axis preferred orientation of HA coatings Sample I (002) I (211) I (112) I (300) I (002)R P (002) Criterion I s R= Enamel i=0.01 ma cm i=0.05 ma cm i=0.1 ma cm i=0.5 ma cm i=1 ma cm i=2.5 ma cm i=5 ma cm i=10 ma cm HA HA, HA, ph ma cm -2,

6 HA EDS HA SEM, Ca/P HA Ca/P, (1.67) (a) 37 ; (b) 55 ; (c) 70 ; (d) 85 Fig.7 7 HA SEM SEM images of the HA coatings formed at different temperature 4 Table 4 HA EDS analysis of the HA coatings formed at different temperature Temperature / Element At / % Ca/P 37 Ca K P K Ca K P K Ca K P K Ca K P K ( i=0.5 ma cm -2, ph 6), Fig.8 8 (002) (004) 1 h, HA XRD ( ) XRD, HA c HA PDF No ( 5) 5, EDS ( 4) HA,P (002), Scherrer XRD, 55, ;,HA ( 5) 55,P (002) P (002) 8 XRD XRD patterns of the coatings formed at different temperature

7 7 : 1193 Table 5 5 HA c Effect of temperature on c-axis preferred orientation and grain size of HA coatings Sample I (002) I (004) I (211) I (112) I (300) I (002)R I (004)R P (002) P (004) Grain Size / nm Criterion I s R=0.182 I s R= (5.593), 55 ; ph 6, 0.5 ma P (004) cm -2, 55, HA c, 70,P (004) 9.989, HA P (004) (4.714), P (004) 4 HA HA (002) HA P (004), 55, HA, 5 HA :, HA, [1] Anderson P, Davis G R. Caries Res., 1996,30(3):394~399 [2] Hellwing E, Lussi A. Caries Res., 2001,35(supple 1):57~59 ( 7) HA [3] Onuma K, Yamagishi K, Oyane A. J. Crystal Growth, 2005, ( 9) 282:199~207 [4] Lalumandier J A, Rozier R G. Pediatr. Dent., 1995,17(1):19 ~25 [5] Chen H F, Tang Z Y, Liu J, et al. Adv. Mater., 2006,18(14): 1846~1851 [6] Liao Y M, Feng Z D, Li S W. Thin Solid Films, 2008,516: 6145~6150 [7] Vijayaraghavan T V, Bensalem A. J. Mater. Sci. Lett., 1994, 13:1782~1785 [8] Shirkhanzadeh M. J. Mater. Sci.-Mater. Med., 1998,9(2):67~72 [9] ZHANG Jian-Min( ), LIN Chang-Jian( ), FENG Zu-De( ), et al. Chem. J. Chinese Universities(Gaodeng 9 HA Xuexiao Huaxue Xuebao), 1997,18(6):961~962 Fig.9 Effect of temperature on the HA coating [10]Zhang J M, Lin C J, Feng Z D, et al. J. Electroanal. Chem., amount (kg m -2 ) 1998,452(2):235~240 [11]ZHANG Jian-Min( ), LIN Chang-Jian( ), FENG 3 Zu-De( ), et al. Acta Phys.-Chim. Sin.(Wuli Huaxue Xuebao), 1998,14(8):698~703 HA [12]Zhang J M, Lin C J, Feng Z D, et al. J. Mater. Sci. Lett.,, ; 1998,17(13):1077~1079 ph [13]LIU Fang( ), LI Zhi-You( ), ZHOU Ke-Chao(, HA; ), et al. J. Cent. South Univ. Tech. (Natural Science), HA, (Zhongnan Daxue Xuebao(Ziran Kexueban)), 2002,33(1):63~ 66, [14]LIU Fang( ), ZHOU Ke-Chao( ), HUANG Bo-,,HA c Yun( ), et al. Mater. Review(Cailiao Daobao), 2002, ;,(002) 16(3):38~40 ; [15]Tanaka K, Iijima Y. J. Dent., 2001,29(6):421~426 ph,ha c [16]Busch S. Angew. Chem. Int. Ed., 2004,43(11):1428~1431