IRUCAA@TDC : Corrosion behavior and surface characterization of Ti-20Cr alloy in a solution containing fluoride

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(1)Title. Corrosion behavior and surface characterization of Ti-20Cr alloy in a solution containing fluoride. Author(s) Alternative. Takemoto, S; Hattori, M; Yoshinari, M; Kawada, E; Asami, K; Oda, Y. Journal URL. Dental Materials Journal, 23(3): 379-386 http://hdl.handle.net/10130/819. Right. Posted at the Institutional Resources for Unique Collection and Academic Archives at Tokyo Dental College, Available from http://ir.tdc.ac.jp/.

(2) Dent l a M ate r i l s J a ou r nl a 2 3( 3). : 37. 9-. 38 6 ,. 2 0 0 4. Cor r os i onBe hav i orandSur f ac eChar ac t e r i z at i ono fTi 2 0 CrAl l oyl naSol ut i on Cont ai ni ngFl uor i de Shi nj iTAKEMOTO l ,Mas ayukiHATTORI l ,Mas aoYOSHI NARI l ,Ei j iKAWADAl ,Kat s uhi koASAMI 2 andYut akaODAl l De pa r t mento fDe nt a lMa t e r i a l sSc i e nc e ･To kyoDe nt a lCo l l e ge ,ト2 2Mas a go ,Mi ha ma ku,Chib a2 6 1 8 5 0 2 ,Ja p a n 2 I ns t i t ut ef o rMa t e r i a l sRe s e a r c h,To ho kuUni v e r s i t y,2 十1Ka t a hl r a,Ao b a ku,Se nd a 19 8 0 8 5 7 7 ,Ja p a n Co r r e s p o nd i nga ut ho r ,Ema i l : t a ke mo t o @t d c . a c . j p Re c e i v e dMa y3 1 ,2 0 0 4 / Ac c e p t e dJune3 0 ,2 0 0 4. Thep ur p o s eo ft hi ss t ud ywa st ol nV e S t i ga t et hec o r r e l a t i o nb e t we e nc o r r o s i o nr e s i s t a nc ea nds ur f a c ec o mp o s i t i o no fa ne xp e r i me nt a lT1 2 0ma s s % Crc a s t l nga l l o yi nas a l i nes o l ut i o nc o nt a i nl ngf l uo r i d e ･Thea l l o yha dagr e a t e rr e s i s t a nc et oc o r r o s i o ni naf l uo r i d e c o nt a i ni ngs l ai nes o l ut i o nt ha nd i dc o mme r c i a l l yp ur et i t a ni um.Ho we v e r ,wl t hc o nf i r me ddi s s o l u t i o no f t i t a ni um a ndc hr o mi um,i tme a ntt ha tt h ef l uo r i d ei nt hes a l i nes o l ut i o nc o r r o d e dt h ea l l o ys l i ght l y.Xr a yp ho t o e l e c t r o n s pe c t r o s c o p ya na l ys ュ sr e v e a l e dt ha tt hes u r f a c ec o mp o s i t i o no ft hea l l o yc o ns i s t e do ft l t a ni um a ndc hr o ml um O Xi d e sc o nt a i n】 +[ Cr ] )r a t i oi nt hes ur f a c eo xl d ef i l md e c r e a s e dwh e ni mme r s e di nf l uo r i d e c o nt a i ni ngs a l l ne i nghyd r o xi d e .The[ Ti ] /( [ Ti s o l u t i o n,t ha tl S ,t hes ur f a c eo xi d ef i l mb e c a mec hr o mi umr i c ho xi d e .The r e f o r e ,t hea l l o yo b t a i ne dgo o dc o r r o s i o nr e s i s t a nc e t of l uo r i ded uet of o r ma t i o no fac hr o mi umr i c ho xi d ef i l m. Ke ywo r d s:Co r r o s 1 0 nr e s i s t a nc e ,Ti t a ni um a l l o y,Fl uo r i d e. I NTRODUCTI ON Ti t ani um andi t sal l oyshav ebe e nus e dasde nt alma, t e r i al sf ori mpl ant s ,c r owns ,br i dge s ,de nt ur ebas e s and or t hodont i cwi r e s . Howe ve r,pr o bl e mss uc h as i mpl ant f r ac t ur e and t ar ni s h of t he de nt ur e bas e havebe e n on t her i s eduet ot he i ri nc r e as e d us ei n c l i ni c alappl i c at i ons . Onec aus eoft he s epr obl e msi s l-3 )i nt oot hpas t e , r e l at e dt ot hepr e s e nc eoff l uor i de mout hr i ns e s ,andpr ophyl ac t i cage nt s ,whi c hi sus e d t ohe l p pr e v e ntde nt alc ar i e s . Anot he rc aus ei sr e 4 )i n de nt ur ebas e l at e dt ot hepr e s e nc eofpe r oxi de s c l e anl ng age nt s . Cons e que nt l y,t he r ei sa s t r ong ne e df ort i t ani um al l oyst ohav eahi ghe rr e s i s t anc e t oc or r os i onc aus e dbyf l uor i deandpe r oxi de s . I n ge ne r al ,t i t ani um and i t sal l oysar ec ov e r e d wi t hapas s i vef i l m ( s ur f ac eoxi def i l m)c ons i s t i ngof l owc r ys t al l i t e ,t hi n,oramor phouss t r uc t ur e s ;t he s e 57 ) . some f i l msar ec or r e l at e dt oc or r os i onr e s i s t anc e r e s e ar c he si nt ot he e f f e c t s off l uor i de on t i t ani um c or r os i oni nas i mul at e dor ale nvi r o nme ntc ont ai nl ng twasf ound t hat f l uor i dehav ebe e nr e por t e d8-19) I c or r os i on r e s i s t anc e de pe nds on f l uor i de c onc e nt r at i on,pH,and amount of di s s ol v e d oxyge n8-10-15) Howe v e r ,af e wr e s e ar c he sr e por t e dt hatt i t ani um al l oyshav ea hi gh r e s i s t anc et oc or r os i on c aus e d by tal .r e por t e du) t hatt i t ni a um f l uor i de. Nakagawa e l e pl at i num or pal l adi um al l oys adde d wi t hal i t t s howe d good c or r os i on r e s i s t anc ei n a f l uor i de c ont ai ni ngs ol ut i on.Thehi ghc or r os i onr e s i s t anc eof t heal l oy wasc aus e dby anodi cpol ar i z at i on oft i t ani um duet os ur f ac ee nr i c hme ntofpal l adi um. Thi s i ndi c at e st hat t he c or r os i on r e s i s t anc e oft i t ani um. al l oysi sr e l at e dt ot hef or mat i onofas ur f ac eoxi de f i l m ont heal l oy. tal .r e por t e d2 0 ･ 2 1 )t hat on t heot he rhand,Oda e an e xpe r i me nt alc as tofTi 2 0mas s% Cral l oy had t hel e as tt ar ni s hamongs e ve r alt i t ani um al l oyswhe n i mme r s e di nanac i di cs al i nes ol ut i onc ont ai nl ngf l uor i deorhydr oge n pe r oxi de . Howe v e r,t hec or r os i on r e s i s t anc eand s ur f ac ec ompos i t i on oft heal l oy l m一 me r s e di ns ol ut i onsc ont ai ni ng f l uor i deorhydr oge n pe r oxi dehavenotye tbe e nc l ar i f i e d. The o bj e c t i v e oft hi ss t udy,t he r e f or e ,was t o de mons t r at et he r e ac t i vi t y oft he Ti 2 0 mas s% Cr al l oyt of l uor i deandt oc har a c t e r i z ei t ss ur f ac e . The r e ac t i vi t ywase xami ne di nt e r msoft hee l e c t r oc he mi c alc or r os i on be hav i or,S ur f ac ec ompos i t i on of t he al l oy,andc onc e nt r at i on ofdi s s ol v e dme t al si n as al i nes ol ut i onc ont ai ni ngf l uor i de . MATERI ALSAND METHODS. e r i al s Mat Expe r i me nt alT1 2 0 mas s% Cr al l oy was made by me l t i ngs ponget i t ani um ( 9 9. 8% orabov e ,Sumi t omo Ti t ani um,Amagas aki ,Japan) and pur ec hr omi um ( 9 9. 9 9%,JMC Ne w Mat e r i al sl nc . ,Tokyo,Japan)i n anar gonar cme l t i ngf ur nac e( ACM01 ,Dai v acLi mi t e d,Chi ba,Japan)i nt oa2 0どbut t on.Theobt ai ne d al l oy but t on was ar c 一 me l t e d and c as ti nt o an al umi namagne s i a.mol d ( Ti t av e s t CB, J･ Mor i t a, Kyot o,Japan)us l ng an ar gonar cme l t i ng/pr e s s ur e i t a, Kyo t o, c as t i ng mac hi ne ( Cyc l ar c H, ∫. Mor Japan) . To maket hec as t i ngs ,t wo t ype sofwax pat t e r n - apl at e1 4× 1 4 × 1mm i ns i z eanda.

(3) S URFACECHARACTERI ZATI ONOFTi 2 0 CrALLOY. ( l ! u n .q Le )^1! Sual uI. 20. 30 40 50 6 0 Di 肘ac t i onangl e,20/. 7 0. 8 0. Fi g. 1 Ⅹr a yd i f f r a c t i o np a t t e r na n do ○p t l C mi c r o g r a p ho ft heTCR a l . c yl i nde r6mm i ndi ame t e rand5 0mm i nl e ngt h we r ei nve s t e d.Spe c i me nswe r ec utf r om t hec yl i nd1mm i nt hi c kne s sf o rt hei mme r s i o nt e s t .Thes pe c e r me nswe r epol i s he ds uc c e s s i v e l ywi t h1 2 0 ,2 4 0 ,4 0 0 i 一 and 6 0 0 gr i ts i l i c o nc a r bi depape r s. He r e a f t e r ,t, e xpe r i me nt alTi 2 0mas s % Crc as t i ngal l o yi sde no t he asTCR. TheXr a y di f f r a c t i o n( ⅩRD)pa t t e r nae d an opt i c almi c r o gr a ph ofTCR ar es ho wn i n Fi g. nd The pe aks obs e r v e di nt he XRD pa t t e r n we r e a1. s i gne dt o αTia nd βTi ,a l t ho ughs hi f t soft hepes pos i t i onsf r om t ho s eofpur e αTiand βTiwe r eo ak s e r ve d. Themi c r o s t r uc t ur eo fTCR i ndi c at e dt hbt hemat r i xwasP p ha s e ,a n dt hat a phas ewasi at c l ude di nt heβ p ha s e . El e c t r o npr o bemi c r o a nal ys Ti ndi c at e dt hatt hec o mpo s i t i on o fTCR c o ns i s t e dI S 8 0. 8mas s% t i t a ni um and1 9. 2ma s s% c hr omi um. o f r e f e r e nc es pe c i me n,t i t ani um pl at e( TI )waspr e pa r As by c ut t i ng f r om a s he e to fc omme r c i a l l y av a i l a b e d pur et i t ani um ( Tigr ade2 ,Ro beSt e e l ,Ja pa n) l e. Te s ts o l ut i . Cons t i t ue nt so het e s ts o l ut i o n we r es o di um c hl o n ft r i de ( NaCl ,Wako Che m. ,Os aka,Ja pan) ,s odio f l uor i de( Nap,Wa koChe m. ,Os aka,Ja pa n) ,a ndd u i m t i l l e d wat e r . Twoki ndso ft e s ts o l ut i o n we r epr s par e d. Ones ol ut i o nc o nt ai ne d0. 1 5 4mo lo fNa Cli e -.

(4) TAKEMOTOe ta l . ( 2 8 5. 0e V) o fhydr o c ar bo n on t he s pe c i me n. The c ompos i t i on a ndt hi c kne s so ft hes ur f a c eoxi def i l m we r equant i t at i v e l yc a l c ul a t e da c c o r di ngt ot her e f e r e nc e s2 2 ･ 2 3 ) ･Empi r i c a lda t a2 2 -2 5 )a ndt he o r e t i c a l l yc al c ul at e d dat a2 6 )o ft he r e l a t i v e pho t oi oni z a t i on c r o s s S e c t i ons we r e us e d f or t he quant i f i c a t i on. The t hi c kne s sofpas s i v ef i l m wasc al c ul at e df r o mt hee f f e c t i v ee s c apede pt ho fphot o e l e c t r o na ndt hei nt e nS l t yr at i o ofo xi det o me t alunde rt hea s s umpt i o n t hatc ont ami nantl aye randpas s i v ef i l me xi s t e duni f or ml y2 7 ) . Thi sme t hodc oul dc al c ul at et het hi c kne s s andc ompos i t i onofpa s s i v ef i l ms i mul t a ne ous l y.. St at i s t i c alanal ys e s Thec or r os i onpa r a me t e r s ,Eop e n, Rp,andZo 5, t hec o nc e nt r at i onsofdi s s o l v e dme t al s ,andt hepH we r es t a t i s t i c al l y anal yz e d us l ng a i t e s ta nal ys i sa ta s l gni f i c anc el e v e lo f5%. RESULTS. El e c t r o c he mi c alpr o pe T ･ t y The pot e nt i odynami c pol ar i z a t i on pr of i l e so f TCR a ndt heTIi n SAL a nd NAP ar es hown i n Fi g. 2 .. TIwe r es po nt a ne ous l ypa s s i v a t e di n CR aswe l las t hec ur v e so fbo t hTCR a ndTIs hi f t S e A dL. I nNAP, c ur r e ntde ns i t yt handi dt ho s ei nSAL.T t oahi ghe r l a r i z e di n NAF ha da heTCRpopa s s i v a t e dr e gi o nt ha nT l o I we rc ur r e ntd e ns i t yl nt he ani nc r e as ei nt hec ur r e ntd .e Thec ur v e so fTCR s how oft hedi s s ol ut i o nofc hr o m ns i t ya t+0 . 7V be c aus e Ta bl e1l i s t st hev a l ue so i um. fEop e n, Rp,a nd lT t ai ne df r o mt hepo t e nt i odyna mi cpo o 5O bs ho wni nFi g･ 2 ･TheEopen v a l ueo fl a r i z a t i o npr of i l e s l owe rt ha nt ha ti n SAL･ TheRp T v C al Ri nNAFwa s SAL wa sa ppr oxi ma t e l y3 0 0kn･ u eo fTCR i n c m2 ,a .The s ev al ue swe r eno ts t a t i s t i c a ls t hato fTI n d o was e nt ･Whe ni nNAF,TCR ha dal ar ge rRp v a l yd l ui f f e r . Asf ort heIo5 V al ue si nSALbe t we e n et TI han TI ,i ti sa ppar e ntt ha tt he r ewe r eno TCR a nd f e r e nc e s .TheIo5 V t at i s t i c aldi f al ue so fbo t hme t as l a r ge rt ha nt he y we r ei n SAL. T l si nNAFwe r ･ e e TCR and TIi n NAP we r e1 6 . 6×h 1 0Z 6 o5 V al ue sof 8 9. 9 × 10 6A/C m2r e s pe c t i v e l y,i ndi c a t A/C m2and. ( ︺ OS .N')>Jl e! T uaT Od. S c a E l M l ys l gni f i c antdi f f e r e nc e . i ngas t at i s t i o b s e r v at i o n Thes u r f a c et e x t ur e so fTCR be f o r e s i o ni nSAL a ndNAP ar es ho wn a nda f t e ri mme r andt ha to fTIa f t e ri mme r s i o ni ni nFi gs . 3( a) ( C ) , Fi g. 3( d) . Sc r a t c he s ma de by pNAP i ss howni n s e r v e do nt heTCRsi mme r s e di nS o A l i L s hi ng we r e obs uc hs c r a t c he swe r el i ke wi s eo b andNAF,and f or ei mme r s i o n, Whi l et he T s e I r v e do nt heTCR be u ) ) ,s s howe dge ne r alc or r o s i o n( Fi g. 3( d i mme r s e di n NAF mor phol ogy wa c hc or r os i o n c ha nge si ns ur f a s c e no to bs e r v e do nt he TCRs . No TCRsi mme r s e mo r pho l o gywe r eo bs e r v e do nt he. 1 0 9 1 08Cu 10 r r 7 en1 0 6 1 0 5 1 04 1 0 3 1 0 2. S T ･ f a e Nu a p .c di ns al i nes o l ut i o nswi t h orwi t hout TheCr2 c p ha ,r T a i c t 2 e p r i , z an t i d o n 0 IsXPSs p f o r e and af t e ri mme r s i o ni n SAL e c t r ao fVCR be s howni nFi g. 4 ,Spe c t r um " AS"i sar a e n f d NAF a r e me n po l i s he d wi t hs i l i c o nc a r bi d epa pee r e nc es pe c i 一 gr i t s( be f or ei mme r s i o n) . TheCr2 ppt o6 0 0 PXru PSs. Fi g. 2 Typ i c a l p o t e nt i o d t y d na e m ns ii t y/A･ cm2 f o rTCRa n dTIi nS ALa cn p dN o l a r A i z F a . t i o np r o f i l e s. a w n a d5 sd 7 e 6 c o . 7e mp V o s , e di O r l n gt i n ot at w i n op gr e e a s k psa e c t i tc v e l l yf o s et r o m o5 t 7 e 3 c . t 8e r um V Judgi ngf r o mt hepo l a r i z a t i o nc ur v e ,T 3 8 1. Ta b l e1 Op e nc i r c u i tp o t e n t i l( a Eopen t al l i cs t at e( Cr O )a ndt heo xi des t a t e( Cr 3 +) 2 2 ) h . eme The ) f r o ml i n e a rp o l a r i z a t i o nt e s t , a n a f t e dp r3 a 0 s 1 s m i v i e n u c t u e r r i m e n m te d r e s n i o s n i t , ya p o t l a r + i z 0 a . 5 t 0 l O nr V( e I s o i s t nc a e( Rp) o b t i an e d p o t e nt i o d yna icp m o l a r i z a t i o nc u r v e ss h o wni nFi g. 2 ,f o rVCRa n dT 5 )o b t a i n e df r o mt h e Me t a l. TI **. S o l u t i o n. Eopen ( Ⅴ). Rp ( knc m Ii nS ALa n dNAF. N S A AL F. 1 1 4 . 8 a -0 . 3 6 ±0 0 7 b. 3 7 5 ±3 1 7 2 a 2 ) 6 0 0 b. N s AL F. -0 , 3 6 6 8 ±0 . 0 5 8 C b. 3 0 0 ±1 4 7 a. 1 9 F L A 0 / . C 3 m a2 ) 1 6 . 6 ±. IoS . (. 1 . 7 ±0 1 2 . 1 . 6 a b.

(5) 3 82. SURFACE CHARACTERI ZATI ON OFTi 2 0 CrALLOY. r. ,( C ) )be f or eandaf t e b) Fi g. 3 SEM phot ogr aphsoft heTCR ( ( a),(. ( 1! un .qL e). ul. A )!S u a t.

(6) 3 8 3. TAKEMOTOe ta l . Ta b l e2 Fr a c t i o no fO2,oH ,a n dH2 0i nt h es u r f a c eo x i d ef i l mso nt h eTCRa n dt h er a t i oo fp r o p o r t i o no fOH t ot ha to fO2,[ oH ]/[ 02] so l ut i o n [ 02] [ oH ] [ H20] [ OH ]/[ 02 ] AS* 0 , 5 0±00 3 0 . 3 5 ±0 . 0 1 0 . 1 5 ±0 . 0 4 0 . 7 0 士0 . 0 3 a S AL 0 . 6 1±0 . 0 4 0 . 2 7 ±0 . 0 3 0 . 1 2 ±0 . 0 3 0 . 46 ±0 . 0 9 b NAF 0 , 5 6 ±0 . 0 4 0 . 3 3±0 . 0 2 0 . 11±0 . 0 3 0 . 5 9 ±0 . 0 7 b * ASi nd i c a t e sb e f o r ei mme r s i o n N-4 ,Av e r a g e ±s t a nd a r dd e v l a t i o n Th ed i f f e r e ntl e t t e r s( a ,b )i nd i c a t es t a t i s t i c a ld i f f e r e nc e sb e t we e ng r o u p sb a s e do nt t e s t Ta b l e3 Co mp o s i t i o na ndt h i c kn e s s( t )o ft h es ur f a c eo x i d ef i l mo nt h eTCRb e f o r ea nda f t e ri mme r s i o ni nas a l i nes o l u t i o nwi t ho rwi t h o utf l u o r i d e. AS SAL NAF *. Ti 2 1 . 2±1 . 2 2 0 . 5 ±0 . 5 . 4 1 8 . 4±3. Co n c e n t r a t i o n( a t %) Cr Na 0 7 4 , 1 ±0 . 8 4 . 7±0 . 4 9 . 7±1 . 2 5 . 2 ±1 . 1 4 . 6 ±2 . 6 6 6 . 1±2 . 0 8 . 1 ±2 . 3 4 . 6 ±2 . 1 6. F. 2 . 8±0 . 3. [ Ti ] +[ Cr ] 0 . 8 2 2 . 0 ±0 . 2 0 . 8 0 3 . 9 ±0 . 2 0 . 6 9 3 . 9 ±0 . 5. * ASi n d i c a t e st hep o l i s he dTCR ( a s p r e p a r e ds p e c l me n) N-4 ,Av e r a g e ±s t a n d a r dd e v i a t l On 0 8 C. □ cr. 0 6. 国 Ti. 号. Z巨. 0. 3. 4. T lJ. ･B. 0 2. uO! 1 e L T uaUuOU 一t 3t auJ Pa^O lS S!Q. s pe c t r aofTCRsi nt heCr2 pr e gl O na f t e ri mme r s i o n i n SAL and NAF had a s ma l l e r Cr Ope ak a nd a l ar ge rCr 3+ p e a kt hant ha to fAS･I nt heTi2 p XPS s pe c t r um,t hes pe c t r um de c ompo s e di nt ope a kso r l gト nat l ngatTi O ,Ti 2 +,Ti s +,a ndTi 4+o fTi2p3 /2a ndTi 2 pl / 2 ,aSS hown i n Fi g. 4( b)2 4 ･ 2 5 ) . Not et hei nt e ns i t y oft heTi Ope ak:t hos eofTCRsi mme r s e di nSALa nd NAF we r es ma l l e rt han t hos eofAS. Al t ho ugha l l s pe c i me nss ho we d mai nl yt heTi ヰ+ s t at e ,t heo xi da t i on ofTCR pr o gr e s s e d dur i ng i mme r s i o ni n SAL andNAF. The0 I sXPSs pe c t r um wa sde c o mpo s e d i nt ot hr e epe a kso r i gi na t i ng f r o m me t alo xi de ,02 -, hydr oxi de o r hydr o xylgr o ups ,OH ,a nd hydr a t e and/o rads or be dwat e r ,H2 02 2 ) . Tabl e2l i s t st hef r ac t i o no fe ac hpe aki nt hes ur f ac eoxi deand t her at i o ofpr o por t i on o fOH t o t hatofO2 ㌦[ OH ] /[ 02] .The r ewe r ehydr o xi deo r hydr oxylgr oupson t heTCRs , The [ OH ] /[ 02] r at i o oft heTCRs dur i ng i mme r s i on i n SAL a nd NAPde c r e as e dbe c aus et hef r ac t i onofO2 i nc r e a s e d. Tabl e3r e v e al st he c ompo s i t i on, [ Ti ] /( [ Ti ] + [ Cr ] ),andt hi c kne s s( t )oft hes ur f ac eo xi def i l mo n t heTCRsasde t e r mi ne d by XPS anal ys i s . Ca r bo n a nd ni t r oge n we r ede t e c t e di na ddi t i o nt oe l e me nt s l i s t e di nt het a bl e ,butt he s ee l e me nt swe r er e mov e d f r om t hec ompo s i t i o nc al c ul a t i onbe c aus et he yor i gi nat e df r om ac ont ami na ntl aye r. Onal lTCRs ,t i t ani um and c hr o mi um o ngl na t i ng f r o m c o ns t r uc t i v e e l e me nt soft hea l l o y we r ede t e c t e di nt hes ur f a c e o xi def i l ms .I naddi t i o n,S o di um wa sde t e c t e do nt he TCRsi mme r s e di nSAL a ndNAF,andf l uor i newa s de t e c t e d on t he TCR i mme r s e d i n NAF. The [ Ti ] /( [ Ti ] +[Cr]) rati os o ft he AS a nd SAL i mme r s e dTCR we r e0. 8 2a nd0. 8 0r e s pe c t i v e l y. The di f f e r e nc ei nr a t i oswasno ts t at i s t i c al l ys l gni f i c a nt .. a. SAL. NA. Fi g. 5 Th ec o n c e n t r a T t i C o n R s P N T A I P t l t a ni u mi nS A o fd i s s o l v e dc h r o mi um a nd s i o n,a ndt h ec o n L c e a n n t r dN a AFa f t e rTCR i mme r i nNAPa f t e rTIi m t l O nO fd i s s o l v e dt i t a ni um Di f f e r e ntl e t t e r s( a , m ち, e r C s i o nf o r3d a ysa t3 7 ℃. e d i f f e r e n c e sb e t we )i n d i c a t et h es t a t i s t i c a l. I nc o nt r as t ,TCR i nNAP ng r o u p sb a s e do nと t e s t . [ Cr ] )r a t i oc o mpa r e d hadas mal l e r[ Ti ] /( [ Ti ] + TCR. Thet hi c kne s so f t oA t h Sa ndt heSALi mme r s e d wa s2 . 0nm,a ndt het h es ur f a c eo xi d ef i l m onAS a ndNAPwa s3 . 9mm.T i c h k i ne s so nt heTCRsi nSAL m o ft hes ur f ac eo xi def i l mi sme a n st h a t t het i c kne s s n c r e a s e dd u r i n gi mh i C nb o nc o e t n hs t r a o t l i u o t no i o ns . e r s i on Thec o nc e nt r a t i o nso fd i ne fd i s s o l v e dT t al sandpH mi um i n SAL a nd N s s o l v e dt i t ani um and c hr os ho wn i n Fi g. 5. I nA ad P d i af t e rTCR i mme r s i on ar e.

(7) S URFACECHARACTERI Z ATI ONOFTi 2 0 CrALLOY. ha v e be e bod yf l ui ds o ra r t i f i c i als a l i v as o l ut i ons o t h e i rr e s u t s ,t i t a n i u me a n d i Ac c o r d i ng nt i nv e s t i ga t e dl b y s e v e r a lr s e a r c he r s 3 0 -3 6 ) ha d hi gh c o r r o s i o nr e s i s t a nc ebe c a us eo fa t sa n l l oys f i l mt ha tf o r me do nt hes ur f ac e . Ho we v e r,t he oxi de f ac eo xi def i l mss uf f e r e df r o mf l uo r i deat t ac ks s ur 1 ut i o nsc o nt a i nl ngf l uo r i de ,ma r ke dl y de c r e as ii ns oc o r r o s i o nr e s i s t anc eo ft het i t a ni um a l l o ys. ng t he a mpl e ,t hec ur r e ntde ns i t ya tpas s i v er e gl OnO Ff ore xni um o r Ti 6 Aト4 V i n as o l ut i o nc o nt a i ni ng ab t i o t u a t t O h ･ 2 % s o di u msa f l u o r i d ea ( 9 0 5pp m F )i nc r e as e d mワ r e a n2 0t i me sc o mp r e dw i t ht h o s ei nas ol u t l O n. Fi g. 6 Thep S A HL i n TCR N AP T NA IP a ndt ha ti nN SAA La PndNAFa f t e rTCRi mme r s i o n 7 ℃." Bl a n k"i a t3 a f t e rTIi mme r s i o nf o r3d a y s s p e c i me ni mme r snd i c a t e st h es o l u t i o nswi t h o u t i nd i c a t e t he i o n.Di f f e r e n tl e t t e r s( a ,b,C ) gr o u p sb a s e do ni s t a t t i s t i c a ld i f f e r e nc e s b e t we e n. wi t h I o n utf t h l i u ss o r i t d u e d 1 y 4,a 1 6 ) TCR i go odc o r r o s i o nr e s i s t a nc es n a s a l i nes o l ut i on ha d butt hec o r r o s i o nr e s i s t a i mi l a rt ot ha to ft i t ani um, i nas a l i nes o l ut i o nc o ntnc ede c r e a s e dwhe ni mme r s e d i nl ngf l uo r i de .Ne ve r t he l e s s i nt hef l uo r i de c o nt ai na , r e ntd e ns i t ya t+0. 5i ngs a l i nes o l ut i o n,TCR' sc ur o fTI ,i ndi c a t l ngt V wa so ne f i f t hl owe rt ha nt ha t r o s i o nr e s i s t a nc et ha tTCR c l e a r l yhadahi ghe rc o r f as ma l l e ra mo unto a nTI .I naddi t i o n,t heTCR had. di s s ol v e dt i t a ni um a f t e re T I t .i mme r s i o ni n NAP s s hown asa r e f e r e nc e .I n SAL,t hedi s s o l v e dc hr o i s mi d e t u e m c t and t i t ani um c onc e nt r a t i ons we r e be l ow t he i o n l i mi to fI C P . I n N A mi P , t h ed i s s o l v e dc h r o um andt i t a ni um c onc e nt r a t i o nswe r el ･ 9±0 ･ 5/ ∠ g / c m2and5 6. 5±9. 7〃g/c m2 ,r e s pe c t i v e l y. Thedi s s o l v e d t i t a ni um f r om TCR was f r om TI( 7 0. 6±5 . 2〃 s t at i s t i c a l l yl e s st ha nt hat Fi g. 6S howst hec g/c h m2 an ) g . e si n pH v al ue swi t ho r w ue i s t houts pe c i me ni mme r s i on. No t et ha tt hepH v a ト i nc r e i a nS s e d ALbar e l yc ha nge d,whi l et hev al ue si nNAP v al ue due byt o a pp T r C o xi ma t e l y 0. 4 . Thei nc r e a s e d pH s mal l e rt hant hatd R uet i mme o r s i on was s l gni f i c ant l y. I nt he1 DI SCU i mme SSI Or N s i o nofTI . hi gh t e n 9 s 80 S ,Ti Cral l o yswe r er e por t e da sha v i ng c as t abi l i t yi l es t r e ngt h, go od duc t i l i t y, a nd goo d andCoC f o rde nt alc a s t i nga l l o ysa swe l la sNi Cr i t sal l ral l oys 2 8 2 9 ) ･ Re c e nt l y,a mo ngt i t a ni um a nd ni s oys,TCR wa sc o ns i de r e dt oha v et hel e as tt a r i de 2 h 0 , 2r e s ul t i ng f r om f l uo r i de and hydr oge n pe r o xhav 1 )n I t mi g h t beu s e f u l t ok no w t h ec o r r o s i o nb e i o ra ds u r f a c es t r u c t u r e sofT CR , i fan e w t i t a ni um al l oy wi t hane xc e l l e ntc o r r os i on r e s i s t anc f l uor i dewe r et obede s i gne d. I nt h et o wee xami ne dt hee l e c t r o c he mi c alprepr e s e nts t udy, f ac ec ompos i t i onsofTCR i n as al o pe r t i e sa nds ur t ai ni ngf l uor i de ,andde mons t r a t e di nes o l ut i o nc o nT Ch o r ec r o s o i r o r nr os i e o s n i s t a n c e t sr e a c t i v t y . b e h a vi o ro ft i t a ni umi a ndi t sa l l o y si n. s i mul a t e d.

(8) TAKEMOTOe ta l . S ur f ac eoxi def i l mo nt heTCR i mme r s e di nas a l i ne s ol ut i on c ont ai nl ng f l uo r i deha dahi ghe rc hr o mi um c ont e ntt han t hef i l m i n as al i nes ol ut i o n wi t hout f l uor i de ,ass ho wni n Tabl e3. Whe n TCR wa si m一 me r s e di n as al i nes o l ut i o nc ont ai nl ng f l uo r i de ,t he f r ac t i on of di s s ol ve d t i t ani um ( [ Ti ] /( [ Ti ]+[ Cr ] ) was 0. 9 6i nI CP a nal ys ュ s ,i ndi c at i ng t ha tt i t a ni um wasdi s s ol vi ng f r om TCR s e l e c t i v e l y. Cons e que nt l y, t heTCR i mme r s e di nas al i nes ol ut i on c o nt a i ni ng f l uor i dehadac hr omi umr i c ho xi def i l m,whi c hwa s mor er e s i s t antt of l uor i de . OH ] /[ 02] r at i oo fTCR de c r e a s e dwhe n The [ i mme r s e di ns a l i nes ol ut i o ns ,ass hown i n Ta bl e2 . Thi sde c r e as ec oul dbee xpl ai ne dbyt hede hydr a t i o n andoxi dat i ono ft hehydr o xylgr o ups .Ho we v e r ,t he f i l mss t i l lc ont a i ne dt he hydr oxylgr oupsa nd hydr oxi de . The r e f or e ,t hes ur f ac eo xi def i l mso nTCR wi l lc ons i s tofoxi de ss uc ha sTi O,Ti 2 03 ,Ti O2 ,a nd Cr 2 03i nt hei nne rl a ye r ,ando xyhydr o xi de ss uc ha s Ti Ox( OH) 4 -2 x( 0<Ⅹ<2 )a nd Cr Oy( OH) 3 -2 ,( 0<y< 3 /2 )i nt heout e rl aye r ,al t hough a de pt ha na l ys i s wi l lber e qui r e dt oc l ar i f yt hi s ,. Re ac t i o nT nO de l Thec or r os i onr e s i s t anc eo fat i t a ni um al l o yt of l uor i dei sr e l at e dt ot hec ompo s i t i o no ft hea l l o y. Fo r e xampl e ,Ti Pda l l oyspr o v e dt ohav eago odc o r r os i onr e s i s t anc et of l uo r i de l l ) .Theme c hani s mi ss um_ mar i z e dasf ol l ows . Thee nr i c hme ntbyt hepl a t i num f ami l yont hea l l o yac c e l e r a t e st hec at ho di cr e ac t i o n, whi c hi sduet ot hedr awl ng O fe l e c t r ons ,a ndal s o anodi c al l y pol a r i z e st het i t a ni um,r e s ul t i ng l nr a pi d f or mat i onoft hes ur f ac eoxi def i l m. I ns uc hac a s e , t hec or r os i onr e s i s t anc eofTi Pda l l o ysc oul dde pe nd ont hepr o pe r t i e so ft het i t ani um o xi deo nt heal l oys . I nt hi ss t udy,t heme c hani s m t os uppr e s sTCR c or r os i on wasdi f f e r e ntf r o m t ha to fTi Pd a l l o ys . Wes ugge s tt hatc hr omi um o xi de son t heTCR a r e r e l at e dt ohi ghc or r o s i onr e s i s t anc et of l uor i de .Ti t ani um oxi de sonaTCR di s s ol v e di nas al i nes o l ut i o n c ont ai nl ng f l uo r i de ,whi l ec hr omi um o xi de s ba r e l y di s s ol v e d. Cons e que nt l y,c hr o mi umr i c ho xi def i l ms f or me dont heTCR. Thec hr omi umr i c ho xi det he n s uppr e s s e dt i t ani um di s s ol ut i o n and pr e v e nt e df l uo r i deat t ac k. Ho we ve r ,t hedi ff e r e nc ei nt hea mo unt ofdi s s ol ve dt i t ani um be t we e nTCR andTIi sye tt o be ac c ount e df or i nt e r ms o fc o r r os i on r e s i s t anc e . The di f f e r e nc emi ghtbe r e l a t e dt ot he di s s o l ut i o n r a t eoft i t ani um. The r e f o r e ,f ur t he rs t udyi sne e de d t ode t e r mi net hedi s s ol ut i o nr a t e . Thec or r os i o nr e s i s t a nc ee v al ua t e di nt hi ss t udy wasmor es e ve r et han t hatwo ul dhappe n unde rac t ualc ondi t i ons ,be c aus et hea ds o r be d pr ot e i ni n an o r ale nvi r onme ntmi ghtbee xpe c t e dt os uppr e s st he c or r os i on c aus e d by f l uo r i de 1 4 -1 6 ･ 1 9 ) I ti se xpe c t e d t ha ti nanor ale nvi r onme nt ,TCR wi l lhav eamuc h hi ghe rc or r os i onr e s i s t anc et of l uo r i de .. 3 8 5. CONCLUSI ONS I nt hi ss t udy,t hec or r o s i onr e s i s t anc eo fane xpe r i 一 me nt alTi 2 0ma s s % Crc a s t i ng al l o yl naS Ol ut i o n c ont a i nl ngf l uo r i d ewa se xa mi ne di nt e r msofi t se l e c t r o c he mi c alc or r o s i o n be ha v i o r and s ur f ac ec har ac t e r i z a t i on. Ther e s ul t sar es ummar i z e da sf ol l ows. 1.Thec o r r o s i o nr e s i s t a nc eo fTCR i nas al i nes o l ut i o nwass i mi l a rt ot ha to fTI .I nas al i nes ol ut i on c o nt ai nl ngf l uo r i d e ,t heTCR ha dahi ghe rc or r o s i on . r e s i s t a nc et ha nTI 2.The TCR i ndi c a t e d a br e a kdown po t e nt i alat +0. 7V ( v s .SCE) ,t ha ti s ,t heTCR hadagoo dc or r o s i o nr e s i s t a nc ea tupt o+0. 7V. 3.Whe n TCR wa si mme r s e di n as al i nes o l ut i on c o nt ai ni ngf l uo r i de ,ac hr o mi umr i c ho xi def i l m wa s f o r me d. 4.1 nas al i nes o l ut i o nc o nt ai ni ngf l uor i de ,t hedi s s o l ut i o no ft i t ani um f r o m TCR o c c ur r e ds e l e c t i v e l y. Ho we v e r ,t he t o t a la mo unt o f di s s ol v e dt i t ani um f r o m TCR wa smuc hl e s st hant hatf r o m TI . 5.TheTCR hadhi ghc o r r o s i o nr e s i s t a nc ei n as al i nes o l ut i o nc o nt ai ni ngf l uor i deduet ot hef o r mat i on o fac hr o mi umr i c ho xi def i l m. ACKNOWLEDGEMENTS Thi ss t udywa ss uppor t e di npar tbyaGr a nt i nAi d f o rDe v e l o pme nt a lSc i e nt i f i cRe s e ar c h( No.1 3 4 7 0 42 0 ) f r o mt heMi ni s t r yo fEduc a t i o n,Cul t ur e ,Spor t s ,Sc i e nc eandTe c hnol ogy,Ja pa n.Thea ut ho r swo ul dl i ke t o t hank Mr . Kat s umi Tadokor o, Ms . Ei ko Wat ana be ,and Mr .Yo s hi akiKi t az a wao ft heOr a l He a l t h Sc i e nc eCe nt e ro fTo kyoDe nt alCo l l e gef o r t he i ri nv al uabl es uppo r ton t hee xpe r i me nt s . The a ut hor swoul da l s ol i ket ot ha nkMr .Nao f umiOht s u o ft he I ns t i t ut eo fMa t e r i a l s Re s e a r c ho fTo hoku Uni v e r s i t y f o rt he XPS me a s ur e me nt s , and Dr. Da i s uke Kur o da and Mr .Ta t s unor i Oya of t he Bi o mat e r i a l sCe nt e ro fNa t i o nall ns t i t ut ef orMa t e r i a l sSc i e nc ef o rt he i rma nyhe l pf ulc o mme nt s . REFERENCES i ) La us ma aJ,Ka s e moB.Ha n s s o nS.Ac c e l e r a t e do x i d e. g r o wno nt l t a n i u mi mp l a nt sd u r l nga u t O C l a v l n gC a u s e d b yf l u o r i n ec o n t a mi n a t i o n.BI O ma t e r i a l s1 9 8 5 ;6 :2 3 2 7 . 2 ) Pr 6 b s t e rL,Li nW,Hi i t t e ma n nH.Ef f e c to ff l uo r i d e p r o p hy l a c t i ca g e n t so nt i t a ni u ms ur f a c e s .I nt∫Or a l Ma x i l l o f a cl mp l a nt s1 9 9 2 ;7 :3 9 0 3 9 4 . 3 ) Oz e k lK,Od aY,S u ml iT.Th el n f l ue n c eo ff l u o r i d e p r o p h yl a c t i ca g e n t so nt h ec o r r o s l O nO ft i t a nl u ma nd t i t a n i um a l l o y.S h i k waGa ku h o1 9 9 6 ;9 6 :2 9 3 3 0 4 . 4 ) Ab e T,Ma t s u mo t o M,Ha t t o r iM,Ha s e g a wa K, Yo s hi n a r iM,Ka wa d aE,Od aY.Di s c o l o r a t i o no ft i t a n i umi n d uc e db yd e n t u r ec l e a n e r .∫∫De n tMa t e r2 0 0 1 ; 2 0 :3 6 6 3 7 1 . 5 ) Ha na waT,Ot aM.Cha r a c t e r i z a t i o no fs u r f a c ef i l m.

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SURFACE CHARACTERI ZATI ON OFT1 2 0 CrALLOY. f o r me do nt i t a ni um i ne l e c t r o l yt eus i ng XPS.Appl Sur fSc i1 9 9 2 ;5 5 :2 6 9 2 7 6 . 6 ) OngJL,Luc a sLC,Ra i ka rGN,Co nna t s e r氏,Gr e go r y JC.Spe c t r o s c o pi cc ha r a c t e r i z a t i o no fpa s s i v a t e dt i t ani um i n a phys i o l ogl Cs ol ut i o n.∫ Ma t e r S° iMa t e r Me d1 9 9 5 ;6 :1 1 3 1 1 9 . 7 ) HanawaT,As a miK,As a o kaK.Re pa s s i v at i o noft i t a ni um a nds ur f ac eo xi def i l mr e ge ne r a t e di ns i mul at e d bi o l l qui d.∫Bi o me dMa t e rRe s1 9 9 8 ;4 0 :5 3 0 5 3 8. 8 ) OdaY,Ka wa daE,Yo s h i na r iM,Ha s e ga waK,Oka be T.Thei nf l ue nc eo ff l uo r i dec o nc e nt r a t i o no nt hec o r r o s i o no ft i t a ni um a nd t i t a ni um a l l o ys .∫ ∫ De nt Ma t e r1 9 9 6 ;1 5 :3 1 7 3 2 2 . 9 ) Re c l a r uL,Me ye rJM.Ef f e c t so ff l uo r i de so nt i t a ni um a ndo t he rde nt a la l l o ysi nde nt i s t r y.Bi o ma t e r l a l s1 9 9 8 ; 1 9 :8 5 9 2 . 1 0 ) Na ka gawaM,Ma t s uyaS,Shi r a i s hiT,Oht aM.Ef f e c t o ff l uo r i dec o nc e nt r at i o nandp Ho nc o r r o s i o nbe hav i o r o ft i t a ni um f orde nt alus e .∫De ntRe s1 9 9 9 ;7 8:1 5 6 8 1 5 7 2 . l l ) Na kagawaM,Ma t s uyaS,Ud o hK.Cor r o s i o nbe ha v i o r o f pur et i t a ni um a nd t i t a ni um a l l o ys i nf l uo r i de c o nt a i nl ngS Ol ut i o ns ,De ntMa t e r∫2 0 01 ;2 0 :3 0 5 31 4 . 1 2 ) Na kaga waM,Ma t s uyaS,Ud ohK,Ef f e c to ff l uo r i de a ndd l S S O l v e do xyge nc o nc e nt r a t i o nso nt hec o r r o s i o n be ha v i o ro fpur et i t a nl um a nd t l t a ni um a l l o ys .De nt Ma t e r∫2 0 0 2 ;2 1 :8 3 9 2 . 1 3 ) Sc hi f fN,Gr o s go ge a tB,Li s s a cM,Da l a r dF.I nf l ue nc e o ff l uo r i dec o nt e nta ndpH ont hec o r r o s i o nr e s i s t anc e o ft i t ani um a ndi t sa l l o ys .Bi o mat e r i a l s2 0 0 2 ;2 3:1 9 9 5 2 0 0 2 . 1 4 )I deK,Ha t t o r iM,Ha s e ga waK,Yo s hi nar lM,Kawa da E,OdaY.Thee f f e c to ff l uor i d ea ndal bumi no nc o r r o s i o no ft i t a ni um.JDe ntRe s2 0 0 1 ;8 0 :6 6 3 . 1 5 )I deK,Ha t t o r iM,Yo s hi na r iM,Ka wa d a E,OdaY, Thei nf l ue nc eo fa l bumi no nc o r r o s i o nr e s i s t a nc eo ft i t a ni um i nf l uo r i d es o l ut i o n. De ntMa t e r∫2 0 0 3 ;2 2 :3 5 9 3 7 0 . 1 6 ) Hua ngHH.Ef f e c t so Hl uo r i dea nda l bumi nc o nc e nt r a t i o no nt he c o r r o s i o n be ha v i or o fTi 6 Al 1 4 V a ll o y. Bi o ma t e r l al s2 0 0 3 ;2 4 :2 7 5 2 8 2 . 1 7 ) Ka ne ko K,Yo ko ya ma K,Mo r i ya ma K,As a o ka K, Sa ka i∫,Na humoM.De l a ye df r a c t ur eo fbe t at i t a ni um o r t ho do nt i c wi r e l n f l uo r i de a que ous s o l ut i o ns . Bi o ma t e r i al s2 0 0 3 ;2 4:2 1 1 3 2 1 2 0 . 1 8 ) Yo ko yama K,Kane ko K,Mo r i ya ma K,As a o ka K, Sa ka i∫,Na ga moM.De l a ye df r a c t ur eo fNトTis upe r e l a s t i ca l l o ysi na c i di ca ndne ut r a lf l uo r i d es o l ut i o n,∫ Bi o me dMa t e rRe s2 0 0 4 ;6 9 A:1 0 5 1 1 3 . 1 9 ) Ta ke mo t oS,Ha t t o r iM,Yo s hi na r iM,Ka wadaE,Oda Y.Co r r o s i o nbe ha v i o ra nds ur f a c ec ha r a ct e r i z a t i o no f t i t a ni um i n as o l ut i o nc o nt inl a ng f l uo r i dea nd a lbumi n.Bi o ma t e r i al s .I npr e s s . 2 0 ) OdaY,Ha t t o r iM,Yo s hi na r iM,Ka wa daE.Di s c o l o r at i o no ft i t a ni um a ndt i t a ni um al l o yswl t hpe r o xi dea nd f l uor i d es ol ut i o n.∫ De ntRe s( Spe cl s sB)2 0 0 3 ;8 2 : 3 0 8 . 2 1 ) OdaY,Ha t t o r lM,Kawa d aE,Yo s hi nar iM,Ta ke mo t o. SJnf l ue nc eo fpH o nt het i t a ni umba s e dal l o ysc o r r o s i o nwi t hf l uo r i de .∫De ntRe s( Spe cl s sA)2 0 0 4 ;8 3 : 0 6 3 0 . 2 2 ) As a miK,Ha s hi mo t oK.Xr a ypho t o e l e c t r o ns pe c t r ao f s e v e r a lo xi d e so fi r o na ndc hr o mi um.Co r r o sS° i1 9 7 7 ; 1 7 :5 5 9 5 7 0. 2 3 ) As a mlK,Ha s hi mo t o冗,Shi mo da i r aS.XPSde t e r mi nat i o no fc o mpo s i t i o nso fa l l o ys ur f a c e sa nds ur f ac eo xi de so n me c ha ni c a l l y po l i s he di r o nc hr o mi um al l o ys . Co r r o sS° i1 9 7 7 ;1 7 :7 1 3 7 2 3 . 2 4 ) As a mi K, Che n SC,Hab az a ki H,Ka wa s hi ma A, Ha s hi mo t oK.A pho t o e l e c t r oc he mi c a la ndESCA s t udy o fpa s s i v i t yo fa mo r pho usni c ke l v a l v e me t a lal l o ys . 1 9 9 0 ;3 1 :7 2 7 7 3 2 . 2 5 ) As a miK,Che n SC,Ha ba z a kiH,Ha s hi mo t oK.The s ur f a c ec ha r a c t e r i z a t i o n o ft i t a ni um a nd t i t a ni umnl C ke la l l o ysi ns ul f ur i ca c i d.Co r r o sS° i1 9 9 3;3 5 :4 3 4 9. 2 6 ) Sc o f i e l d JH.Har t r ･ e e Sl a t e r ･s ubs he l lphot oi o ni z a t i o n c r o s s S e c t i o ns a t 1 2 5 4 a nd 1 4 8 7 e V. ∫. El e c t r o n Sp e c t r o s cRe l a tPhe no m1 9 7 6 ;8:1 2 9 1 3 7 . 2 7 ) Ha na wa T.Cha r a c t e r i z a t i o no fs ur f a c ef l l msf o r me d o nt i t ani um i ne l e c t r o l yt i cs o l ut i o ns .∫∫De ntMa t e r 1 9 8 9 ;8:8 3 2 8 4 4. 2 8 ) Shi mi z uA.St ud i e so nt i t ni a um a ll o ysf o rde nt lc a a s t 1 ng.Par tI .Ef f e c t so fPda ndCro nt i t a ni um pr o pe r t i e s .∫∫De ntMa t e r1 9 8 6 ;5:1 2 2 1 3 2 . 2 9 ) Shi mi z uA.St udi e so nt i t a ni um al l o ysf o rde nt alc a s t 1 ng.Pa r tI I .Ef f e c t so fa dd e de l e me nt st oTト2 0 Cra 1 l o ysa ndTi 2 5 Pdal l o ys .∫∫De ntMa t e r1 9 8 6 ;5 :1 3 3 1 4 3 . 3 0 ) Wi l l i a msRL,Br own SA,Me r r i t tK.El e c t r o c he mi c a l s t ud i e so nt hei nf l ue nc eo fpr o t e i nso nt hec or r o s i o no f i mpl a ntal l o ys .Bi o ma t e r i a l s1 9 8 8;9 :1 8ト1 8 6. 3 1 ) KhanMA,Wi l l i a msRL,Wi l l i a msDF.Thec o r r o s l O n b e ha v i o ro fTi l 6 A1 4 V,Ti 6 A1 7 Nba ndTl 1 1 3 Nb1 3 Zri n pr o t e i ns o l ut i o ns .Bi o mat e r i al s1 9 9 9 ;2 0 :6 3 ト6 3 7 . 3 2 ) St r i e t z e lR,H6 s c hA,Kal bf l e i s c hH,Buc hD.I nu かo c o r r o s i o no ft i t a ni um.Bi o ma t e r i a l s1 9 9 8;1 9:1 4 9 5 1 4 9 9. 3 3 ) Br o wnSA,Me r r i t tK.El e c t r o c he mi c a lc o r r o s i o ni ns a 1 i nea nds e r um.JBi o me dMa t e rRe s1 9 8 0 ;1 4:1 7 3 1 1 7 5. 3 4 ) Br uneD,Ev j eD,Me l s o m S.Co r r o s i o no fgo l dal l o ys a nd t i t a ni um l na r t i f i c i a ls a l i v a.Sc a nd ∫ De ntRe s 1 9 8 2 ;9 0 :1 6 8 1 7 1 . nu i t r o as s e s s me nto fc o r r o s i v e 3 5 ) Ko i keM,Fuj i iH.J pr o pe r t l e SO ft i t a ni um a sabl O ma t e r i a L∫Or a lRe hab i 1 2 0 0 1 ;2 8 :5 4 0 5 4 8 . 3 6 ) Ko i keM,Ca iZ,Fuj i iH,Br e z ne rM,Oka beで.Co r r o s i o nbe ha v i o ro fc a s tt i t ani um wl t hr e duc e ds ur f a c er e a c t i o n l a ye r ma de by a f a c e c o a t i ng me t ho d. Bi o ma t e r i a l s2 0 0 3 ;2 4:4 5 4 1 4 5 4 9. 3 7 ) Co r s oPPJr ,Ge r ma nRM,Si mmo nsHD Jr .Co r r o s i o n e v al ua t l O nO f go l db a s e d de nt alal l o ys .∫ De ntRe s 1 9 8 5 ;6 4:8 5 4 8 5 9 . 3 8 ) LiXY,Aki ya maE,Hab a z a kiH,Ka wa s hi maA,As a mi K,Ha s hl mO t O K.Spo nt a ne o us l y pa s s i v a t e df i l mso n s put t e r de po s i t e d Cr i a T ll o ys i n 6 M HCIs o l ut i o n. Co r r o sS° i1 9 9 7 ;3 9:9 3 5 9 4 8..

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