Hypcrfine Interactions 45 (1989) 105-125
105
CORROSION PROTECTION A N D ELECTROCHEMICAL PROCESSES STUDIED BY MOSSBAUER SPECTROSCOPY
A. VI~RTES Laboratory of Nuclear Chemistry, Edtvds U, iversit); Budapest, Pttskin u. 11-13, H-108& Hungary N ~ s s b a u e r s p e c t r o s c o p y i s an e x c e l l e n t tool for several fields of corrosion and e l e c t r o c h e m i c a l researces. This paper demonstrates the applicability of this technique for the study of the corrosion protective o r g a n i c and m e t a l l i c layers, of the interphases between the substrates and c o a t i n g s , o f electrodeposited a l l o y s , and o f t h e e l e c t r o c h e m i c a l p r o c e s s e s on e l e c t r o d e surfaces.
INTROOUCTION The f i r s t papers which demonstrated the usefulness of the N~ssbauer s p e c t r o s c o p y in the s t u d y of c o r r o s i o n were p u b l i s h e d more t h a n 20 y e a r s ago ~ . S i n c e t h a t t i m e t h e N ~ s s b a u e r t e c h n i q u e has become a v e r y i m p o r t a n t t o o l o f t h e s t u d y o f mechanism and kinetics of the corrosion o f i r o n and s e v e r a l h u n d r e d s o f p a p e r s have been p u b l i s h e d i n t h i s f i e l d . Some o f t h e c o r r o s i o n products, w h i c h w e r e n o t known e a r l i e r , have been f o u n d on t h e b a s i s o f t h e N ~ s s b a u e r s p e c t r a . E . g . FeOC1 was f o u n d i n t h e sea w a t e r ~ , f e r r i h y d r i t e as a m e t a s t a b l e comp o n e n t i n NHaNO~ a q u e o u s s o l u t i o n ~ a.s.o. The N ~ s g b a 6 e r s p e c t r a can s e r v e i n f o r m a t i o n - a b o u t the chemical composition, crystalline and m a g n e t i c s t r u c t u r e of-the corrosion protective coatings. Noreover the interface, between the coating and m e t a l s u b s t r a t e , can a l s o be s t u d i e d by t h i s t e c h n i q u e , fhe parameters of the interface are responsible for adhesion properties o f t h e c o a t i n g s and i t i s t h e r e a s o n o f t h e i r importance. E.g. the NSssbauer s t u d y of the k i n e t i c s of the interphase formation between a l u m i n o - p h o s p h a t e o r c h r o m o - p h o s p h a t e c o a t i n g s and i r o n s u b s t r a t e d e t e r m i n e d t h e minimum t i m e o f t h e h e a t t r e a t m e n t w h i c h was n e c e s s a r y t o g e t t h e maximum t h i c k n e s s o f t h e i n t e r p h a s e ~ . Ihis kind of information was v e r y v a l u a b l e t o p r e p a r e t h e o p t i m a l technology of the production of phosphate type corrosion protective coating. The e l e c t r o d e p o s i t i o n and e l e c t r o d e passivation studies are the fields of electrochemistry where a p p l i c a t i o n s of Mbssbauer s p e c t r o s c o p y have i n c r e a s i n g i m p o r t a n c e and more and more e l e c t r o chemical laboratories apply this method. A schematic survey of the applications of M6ssbauer s p e c t r o s c o p y i n t h e c o o r o s i o n s t u d i e s and i n t h e f i e l d s of electrochemistry is c o m p i l e d i n F i g . 1. The v i e w o f t h e N S s s b a u e r r e s u l t s achieved in the fields of corrosion and e l e c t r o c h e m i s t r y c o u l d be t h e theme o f a m o n o g r a p h y . In this paper I will f o c u s my a t t e n t i o n o n l y on c o r r o s i o n protective o r g a n i c p o l y m e r c o a t i n g s and on t h e new r e s u l t s of the N~ssbauer studies in electrochemistry.
qc-) J.C. Ballzc, A.G., Scicnlit'ic Publishing Company
106
A. Vdrtes, Corrosion protection attd electrochemical processes studied by M.S.
Mechanism "-.
Kinetics Phase analysis of the . - corrosion p r o d u c t "
CORROSION I1111111
PROTECTION
~ ~ Metallic deposits 9
Adhesi~es (corrosion inh i bit ors)
9
~ " Orgamc polymers ."
9
Inorganic coatings (RusJ | ron~furmatiun)
/
7
"" 9 Interfa c e, stu 0 "les "
METAL
-" "
SUBSTRATE
ELECTROCHEMICAL processes
Electrodeposition
Chemical composition, c r y s t a l l i n e and magnet ic stucture
Chemical reactions on electrode surfaces
Int e rphase Po ssi vation formation be~w een electrodeposlts and s u b s l r a t e s
F i g . 1. A s u r v e y o f t h e a p p l i c a t i o n s c o r r o s i o n and e l e c t r o c h e m i s t r y . Corrosion
Protective
Organic
of
N~ssbauev
Trans f orma lions in galvanic cells
technique
in
Coatings
The p a r a m e t e r s o f t h e m o t i o n s o f i o n s t h r o u g h t h e p o l y m e r c o a t i n g s are i m p o r t a n t f o r t h e c h a r a c t e r i z a t i o n of corrosion protective properties of the coatings. N ~ s s b a u e r s p e c t r o s c o p y o f f e r e d p r o m i s e as a means f o r generating information about the chemical interaction of the ions i n the p o l y m e r m a t r i x . fwo N~ssbauev a c t i v e i o n s l l 9 m s n 4 + and 57Co2+ were i n t r o d u c e d to~polymer coatings with the aid of potential g r a d i e n t and " F e ~ ions were introduced by concentration g r ~ n t 4 + E m i s s ~ o 2 + 6ss uer spectroscopy was used in the case of Sn and ~s transmission technique was applied for the study of "Fe z. ions in polymer matrix. The chemical interaction between the organic coating and metal substrata also can be studied if the surface of the metal substvate contains NCssbauer active atoms. Emission NCssbauer study of the interphase, between the cobalt substrate and polyimide coatings, is demonstrated in this paper.
~Q
A. I/drl(',s", Corrosion protection attd electrochemical processes studied by M.S.
Emission
M6ssbauer
study of llgmsn4+
and 57Co2+
in po]ymer
coatings LS,6] A cathodic potential between - 0 , 8 and I i 1 ~ X4~versus.O.i N calomel electrode) was used for introducing S and ~ICoZ+ ions into polymer coatings. The main circumstances of the preparation of the samples are given in Table i and in Fi~7 22 The polarization time was 2-4 days. The attempts to introduce Co + ions into polybutadiene and epoxy coatings met with failure even after the polarization time of one week.
lable l Description of preparation M~ssbauer parameters
of tile samples
and the measured
Thickness of the coating (~m)
cathodic ! )otential
pH
}0
-O.B
1.5
O.02M llgmsncl4
poxy
225
-D.B
1.5
,]kyd
90
-O.B
1.5
]kyd
90
-1.5
1.4
0.02M l]gmsncI4 0.02M llgmsncl4 10-6M 57COC12
Organic coating
'olypuladlene
!
Apolied
(aqueous)
(v~
versus
0.1N
IN R e l a t i v e
splitting
Solution
calomel
mm s -I
mm s -I
-0.12 -0.12 -0.06 1.19
1.74
electrode
t o SnO 2 and
oC-Fe.
4
-----5
r2+7_~2~2-2--+--.~ - - 3 . . . . . . . . . . . .
-
2
"~ - - 1 F i g . 2. Scheme o f i n t r o d u c i n g o f c a t i o n s i n t o o r g a n i c c o a t i n g s . 1. M e t a l s u b s t r a t e as c a t h o d e , - 0 . 8 V v e r s u s O.IN c a l o m e l e l e c t r o d e , 2. p o l y m e r c o a t i n g , 3. aqueous s o l u t i o n , 4. Pt a n o d e , 5. c a l o m e l electrode.
107
108
A. V~rtes. Corrosion protection and electrochemical I),'ocesses studied by M.S.
The m e a s u c e d isomer shifts of Sn 4+ ions show that tin ions diffuse into the coating without their CI- anions and it has a vecy ionic c h a r a c t e r in the polymer matrix. The e s t i m a t e d 0 e b y e - W a l l e c [actors of tin in the c o a t i n g s were b e t w e e n 0.17 and 0.51 at room t e m p e r a t u r e ~ . These values are in the same range as the values foc tin in frozen organic liquids ~ . This e x p e r i m e n t a l result suggests that isolated tin ions ace s u r r o u n d e d by organic matrix in the studied samples. The N S s s b a u e r p a c a m e t e c s m e a s u c e d for 57Co2+ ions (see Table I) ace c h a r a c t e r i s t i c [or the chemical bond with c a r b o x y l a t e groups which ace at the end of polymer chains of alkyd: 0
0
n RCH=CH-R'-CO-O-CH 2
CH-CH
-O-C
IL C-O
0
f ( A l l t h e C o ( I 1 ) and F e ( I I ) c o m p o u n d s c o n t a i n i n g carboxylate groups: CoC204, CoC~0~.2H20 . . , . FeC~0 . , FeC03 e t c . h a v e s i m i l a r q u a d r u p a l e splitttngs 1 . 5 5 - 1 . 9 mm s ~14 [ 6 , ~ . ) The N ~ s s b a u e r r e s u l t s p r o v e t h a t Co 2§ i o n s , i n c o n t r a s t with Sn 4§ i o n s , form a c h e m i c a l bond w i t h t h e ~ a r b n x y l a t e g r o u p s of alkyd coating. The N ~ s s b a u e r s p e c t r u m o f ~Co z+ i n a l k y d c o a t i n g i s shown i n F i g . 3.
if)
.... :"7.,'-
"...
..'.'~..." ":'"
C
0 U
9. ~
%.
6,{ §
vVnmls)
F i g . 3. M b s s b a u e r ~ e m i s s i o n s p e c t r u m o f room t e m p e r a t u r e of Co z+ i n an a l k y d c o a t i n g . Transmission
M~ssbauev s t u d y
of
57Fe5+
ions
in
alkyd
and e p o x y
polymers In this secies of e x p e r i m e n t 200 ~ m thick alkyd and 45 ~ m thick epoxy films, cemoved from the sur[ace of t h Q 7 s t a i n l e s s steel panels, were i ~ e r s e d into the s o l u t i o n o[ 0.25N ~ FeCI 3 aqueous solution. The --Fe nuclide was e n r i c h e d to 95 %. fhe applied pH was 0.5; i and 1.5. fhe samples were soaked in the s o l u t i o n 2-10 days and then washed t h o r o u g h l y for 30 s in HCI of the same pH as that of the FeCI 3 s o l u t i o n to remove the a d s o r b e d FeCI 3 from the surface of polymer. The m e a s u r e d N ~ s s b a u e r p a r a m e t e r s are glven in Table 2 and two of the spectra in Fig. 4 and Fig. 5.
A. Vdrles, Corrosion proleclion und electrochemical processes sludied I0' M.S.
Table 2 MSssbauer p a r a m e t e c s of 57Fe3+ i n t h e c o a t i n g s
Coating
Temperature
mm
Alkyd
liquid
Epoxy
fleZd H
T
o.~9(o)
0.72(6) 45.6(8)
+0.48(8)
nitrogen
room
liquid nitrogen
I Relative
+0.~7(Z)
0.66(1)
+0.44(5)
0.12(])
to
F u l l width at the h a l f of maximum -1 mm s
magnetic
Z$E -1 mm 5
s- I
+0.38(2)
room
Effective
Quadrupole splitting
[5ome~
shift
o.79(z)
o.43(z) 4~.7(8)
o.72(5)
=(-iron.
",o
9
e
9
,'.
"""
-'~"~ 9 :
,~'~".
% 9 .o
9 L,~':.~..9
#
""4
-" 9 %-
"
:
:
9
/
{
C
.;,~-'4.~
9.,=; 9
I
0 0
.o * 9
9
}o~
2 .
-
-
-
.
.
.
0+2+4*6 v(mm/s)
F i g ~ T a . ~ M 6 s s b a u e r spectcum of J ' F e )+ i n t r o d u c e d i n t o the a l k y d c o a t i n g 9 Spectcum t a k e n a t room tempecature. Source: 5 7 C o ( P t ) .
I
-8-6
I
I
-4
I
I
I
I
I
I
-2 0 +2 +4 +6 +8 v (mm/s)
[j,.q_3w149M~Jssbauer spectrum of 3/pe § i n t r o d u c e d i n t o the a l k y d coating. Spectrum t a k e n a t l i q u i d n i L r o g e n tempecature.
109
110
tl. VcSrles, Corrosion prolection and electrochemical processes studied I0' M.S.
The t a b u l a t e d d a t a i n d i c a t e t h a t t h e Fe 3+ i o n s p r e c i p i t a t e d within t h e body o f t h e c o a t i n g l a r g e l y as ~-FeOOH p a r t i c l e s . Corlfirmation o [ the c o n c l u s i o n o f th e N 6 s s b a u e r s t u d y was o b t a i n e d from t h e e l e c t r o n m i c r o s c o p i c measurements o f t h e t h i n n e d c o a t i n g s ~ ] . The estimated particle s i z e s o f fl-FeOOH i n s i d e t h e p o l y m e r were lO-lOO nm. The p r e c i p i t a t i o n o f FeCI~ i n t h e s o l u t i o n s t a r t s o n l y above pH = 2 ~ but the f o r m a t i o n o[ #-FeOOH, i n t h e body o f t h e p o l y m e r , t a k e s p l a c e i n d e p e n d e n t l y on t h e pH os t h e s o l u t i o n o u t s i d e t h e coating. On t h e b a s i s o f t h e N 6 s s b a u e r e x p e r i m e n t s a v e r y i m p o r t a n t c o n c l u s i o n c o u l d be d r a w n , namely t h e c h e m i c a l s t a t e o f t h e i o n s d i f f u s e d i n t o t h e p o l y m e r c o a t i n g depends r a t h e r on t h e c h e m i c a l p r o p e r t i e s o f t h e a c t u a l i o n t h a n on t h e c h e m i c a l c o m p o s i t i o n o f th e p o l y m e r . E m i s s i o n M~ssbauer S tu d y o f t h e I n t e r f a c e S u b s t r a t e and a P o l y i m i d e C o a t i n g
Between a C o b a l t
There i s much i n t e r e s t in metal/polyimide systems bec a u s e o f the ability of p o l y J m i d e to t o l e r a t e high temperature, lhe o b j e c t i v e o f t h e N d s s b a u e r s t u d y was t o u n d e r s t a n d t he n a t u r e o f the bond b e t we e n t h i s o r g a n i c m a t e r i a l and a m e t a l s u b s t r a t e . A cobalt s u b s t r a t e was s e l e c t e d f o r t h e s t u d y b e c aus e t h i s e l e m e n t can r e a d i l y be u t i l i z e d i n s t u d i e s based on e m i s s i o n NOssbauer s p e c t r o s c o p y . I t i s r e c o g n i z e d t h a t the c o b a l t / p o l y i m i d e system i s n o t o f wide commercial interest, b u t i t i s hoped t h a t t h e r e s u l t s can be extrapolated to m e t a 1 5 ~ u b s t r a t e s o f more p r a c t i c a l interest ~O]. The r a d i o a c t i v e Co used i n t h e p l a t i n g s o ] u t i o n was c a r r i e r - f r e e and t h e a c t i v i t i e s o f ~lle d e p o s i t e d Co on t h e c o b a t t s u b s t r a t e s were b e t w e e n 7xlO Bq and lO Bq. Thus t h e q u a n t i t y o f t h e d e p o s i t e d c o b a l t on t h e s u r f a c e os t h e s u b s t r a t e was 2.3-3x10 mg w h i c h i s e q u i v a l e n t to l e s s t h a n t h e w e i g h t o f one m o n o ] a y e r o f t h e s u r f a c e o f t h e s u b s t r a t e w h i c h had a d i a m e t e r o f 1.7 cm. E l e c t r o n and o p t i c a l m i c r o s c o p i c s t u d i e s " showed t h a t t h e d e p o s i t c o n s i s t e d o f s m a l l i s l a n d s . Auger s p e c t r o s c o p i c s t u d i e s showed no m e t a l l i c elements other than cobalt. The p o l y i m i d e film was formed from a s o l u t i o n of p o l y a m i c acid (PAA) in N-methyl p y r r o l i d i n e (NNP) on the cobalt s u b s t r a t e by a spin coating technique. The t r a n s f o r m a t i o n of PAA into PI (polyimide) takes ptace as the result of heat treatment and it can be d e s c r i b e d as fo]tows:
/c~c\ H 0 iC~ 0
o§
n
NO N
I _ 2n~70
--N
N 0
0
0
A. Vdr/es, Corrosion protection and elec/roc'hemical processes studied by M.S.
The H~ssbauer spectra w e r e recorded after the deposition of 57Co, after the coating of the sample with PAA and after different heat treatment. The measured results for one sample are given in Table 5. Four of the spectra are shown in Fig. 6. Table 3. Experimental results: measured HOssbauer one o f t h e s t u d i e d sample Isomer
Area
(z) As deposited 57Co
PAA
Ouadrupole splitting
(mm s "l )
for
Magnet c field Te~[a
Half width
27.2-0.2
[.18,0.08
(mm s - ] )
Co ~ Co 2.
74.0 13.5
-0.048~0,027
Co ~+
62.5
-O.)50~O.O0~
&.? 11.6
-O.026~O.ltB -0.I)4~0.022 -},)l * 0 . 1 9
1.80 *0.)8
i.on•
0.908~0.121
0,89.o.12
Co ~ ''~o ~
Coated w i t h
shift ~
(~m s -l )
spectra parameters
I 00.0.04
2,40 0.8~8*0.00)
-1,2l
l.OO-O~Ol
[.)8*n.~A
2;.t~1.2
O.79.O.41
CC2 .
28.8 P~.9 34.7
-0.}27~0,017
Cured a t 85 ~
Co ]+ Co z+
-I,20 tO.02
2.0) ~O.O}
I.O)*O.O6
l o t 17 mln Cured a t 200 ~
Co 3§ Co z*
6~.3 46.0
-0.}~}~0.008
0.788-0.017
O.R8-O.O2
-1.I7
2.10 *0.02
O.?),O.O}
for
Co } *
54,0 21.8 5.6
-0.01~O.205
X2 atmosphere
Co ~ Co 2+
)0 mln
Co ~+
72.5
-0.418,O.O)9
Co 2 .
53.2
Co)O 8 C%O&
)2.2 14,~
20 m~n
"Cured for
a t }65 ~
substrate GOat~nE mmcured a t
0.98,0.0)
O.8~7~O.O25 )).2.1.4
I.Sa•
1.95 * 0 . 8 !
0.8[,0.)9
0.441.0.l)4
1.05-0,08
-l,16
2.00
0 92,0.03
-O,}aT*O.OlO
0.900
-1.20
*0,]8
uithout )65 ~
fl 7 atmosphere for
xO.02 -0.}55~0,011
]0 min
I .O)-0.O7 ogE,o.20
-0.266.0.017
coating o n l y
ii
'The, used a b s o r b e r was s t a i n l e s s coda s u p e l p a l a m a g n e t i c c o b a l t 9
w,w &t )65 ~
the c o a t i n g s e p a | a t e d
steel
but
the i s o m e r s h i f t s
are ielatlve
to
~-re.
from the ~ u b ~ i l a t e 9
The main conclusions drawn from the H~ssbauer data are the following. The PAA coating and the stepwise heat-treatment resulted in chemical transfoEeat~ons at the surface of~the cobalt substrate: J~ u . . . . L+ . . . . ( z ) d e c r e a s e zn . . C o ; ( 1 1 ) zncrease t n Co ; (ztz) z o c r e a s e in Co ) + as l o n g as ) / C o ~ i s p r e s e n t ; (iv) decrease'in Co ) + a t PI stage. The ( i ) and ( i t ) transformations can be e x p l a i n e d by t h e chemical reaction between metallic cobalt and t h e a c i d g r o u p s o f PAA 9
9
Co + R-(COOH) 2
>
R(CO0)2Co
The d o u b l e t with the quadrupole splitting represents Co-carboxylate bonding.
or
+ H2 1.77-1.94
mm s
-1
III
112
/1. lit;ties, Corrosion protection attd electrochemical processes studied by M.S.
o
e
-~ -~ -~
0 .2 J,
.6
W
Z
IL'!li'
0 0
-g-l.-2 Fig.
0 .2 . l . . 6
-6-Z-:2
6 .:2 .i .g
N b s s b a u e r s p e c t r a e l one o f t h e s a mples r e c o r d e d temperature. ( a ) As d e p o s i t e d , ( b ) c o a t e d ~ i t h PAA, ( c ) H e a t e d t o 85~ [o'r 12 min, ( d ) h e a t e d t o 20OuC f o r 20 m i n .
at
6.
s
I h e i n c r e a s e i n Co 3+ t r a n s f o r m a t i o n following reaction 4Co ~ 2H20 + ' 3 l h e d e c r e a s e i n Co 3+ i s between Co )+ and P [ .
the
result
02 of
(iii) ~
is
the
result
of
the
4CoOOH
the chemical
interaction
E 1 e c t rochemi s t r y Electrodeposition The Mbssbauer s p e c t r a o f e l e c t r o d e p o s i k e d l a y e r s can i n f o r m us a b o u t t h e c h e m i c a l c o m p o s i t i o n , c r y s t a l l y n e and m a g n e t i c structure and a b o u t th e r e s i d u a l s t r e s s o f t h e d e p o s i t s ~I-2~ . U s i n g s p e c i a l t e c h n i q u e s , t h e M~ssbauer s p e c t r a o f t h e i n t e r p h a s e between e l e c t r o d e p o s i t s and s u b s t r a t e s can be r e c o r d e d as w e l l . A s u r v e y o f t h e M~ssbauer r e s u l t s p u b l i s h e d on e l e c t r o d e p o s i t s i s g i v e n i n f a b l e 4. One o f t h e most i m p o r t a n t and new f i n d i n g o f t h e MSssbauer t e c h n i q u e f o r t h e e l e c t r o c h e m i s t r y is t h a t the minor c o m p o n e n t , o f t h e e l e c t r o f o r m e d l a y e r s can be d e p o s i t e d i n i o n i c f o r m . E . g . c o b a l t can e x i s t i n t h e c o b a l t h a r d e n e d g o l d e l e c t r o d e p o s i t s i n t h e form o f ~-CoOOH; t i n can be c o d e p o s i t e d w i t h c o p p e r i n th e term o f Sn 4+ c a t i o n ( f a b l e 4 . ) e t c .
A. Vdrtes, Corrosion prolec'tion and electrochemical processes studied by M.S.
Table 4 Compositions l~pe of Plectlndepob~ts
of electrodeposits I'nmpn.nllll,lI nr thl! IIIdtll~!| ~OIUI I011
lg/dm}-) CuCN
B|asb l-&
m%Sn
2.5
Nd2S'IO } NaCN
Ct)l ! Oflt dml~ i | y ( AIdm 2 )
fill
Identified cnl~ound~
12.7-I~.2
~-Cu-Sn ~-Cu}Sn ~-Cu6S %
2.5-5
50
Na2CO~
Co-Sn on Nl-sub~trate
achieved by M6ssbauer spectcoscopy
20 6
Z,tfl
113
R@fslenceb
II
7.5
5,1504 CoS04.7HzO complexln 0 ape,it conductivity salt organic b i l g h t e l t e l surface activator Co/Sn ratio = I
n.}
CoSn ( c u b i c ) dissolved tin y"Co)Sn 2 (hexagonal) CO p a r t i c l e s
0.25
12
5n [ v
0.40
compound Cu-5n on coppe! substrate
Cu~P}010)2] 8Sn~P }010)2] 8Cu/Sn
xI-Sn on Cu-subst[ate
i
XasP}010
latin
75
5n Iv compound L-Cu}Sn ~-Cu-Sn
0,50-0.80
~-Cu65n 5
: }.2
~-Sn
SnC12.2HzO NaF
50
NH4HF2
}5
N~CI2.6HT• 5nCI2.2H20 NaF NH4HF2 X~C12.6HzO
I}
29
0.50
!
25-100 50
0.50
~-Sn Cu-Sn phase
Cu-Sn phase
29
IA
N|~Sn phase
}5 200-400
SnCI2.2H20 NaF
50 29
NHiHF 2
]5
0.50
HI-51! phase
14
fcc-pha~e
15
~upelbatulated ~ o ] i d ~olutlo,1 nf Co ~n Zn
16
]
N|504.7H20 |l|Cl2.6H2n
(r
Fo-N| ~ Ni)
X}80} 3.~-}.5
Ha2504.lO H20 FeS04.7H20 Stdb]lJzet
bllghtenet Zt:504 . 7H20 tie?S0 i . 10 H?O /.-Co
Co50r 7H~0 CI ( 5114 ; ) , 18H20 CHjCOlltla. }HTO
150 ~5 I 0 - 95.4 0. )
75
u.L-,,.2
~-IN
114
A. Vdrtes, Corrosion protection and electrochemical processes studied by M.S.
T~D~ Of
Compn.',lllOll of th,? i:latlauI ~olutln,i ( g/dm} }
el ectz ndepos i t,~
Olosene-Bg Cltlat~-phn~hatn electlolyte, I.c|udlng KAulCN) 2 l } 2 0 ppm Co as Co-chelate Autoronex-C| A l l c i t r a t e ~ystem, Including KAu(CN) 2 Z64 ppm CO as COSO4
Co-fla~dened Au
Oro~ene-80O A l l c i t r a t e system, Including KAu(CN) 2 1)20 ppm Co a~ Co-chelate
||gSn On o x i d i z e d alumlnlum substzate
ll9sn|4 K0H CH~COONa
4.9
}0 ~ H202 CrCI}.6H2O HiCl2.6H2g CeCI2.aH20 "HaCl NH4CI Hj803 in moo0 g 1:10MF*H2O mixture
I0-24 mS Cr 25-5K m% Nl 47-$4 mS Fe of Oreohite substrate
Refmrences
O.l-I
4.}
Sub~titutJone| solid solution qf Co ~n Au. p-CoOgH. Co(CN):Compleses
I
12
24
4.7
25 20 1.5
17 le l?
20
l
O.l
non-stoichiometrlc
2!
Al2Snxn().2x )
1 21.8 47.6 6 29,~
Ferromagnetic Z.~-6.!
~(r,c.c.)
22
Amorphous alloy with three main ~ron ~ o s t t i o n
2)
26.8
9.J
FeSO4.TH2U NeH2PO2,H20 @lycin olal;c-acld
200 7 8.5 0.5
Feg$P 7 on HI substrate
FeSOa.7H20 NaH2P02,H2D glycin oxalic-acid
200 1 8.5
a
Identified compounds
24
Fe@4P16 on Hi iub6tzete
Fe4)Nlk~Pl2 Fe&BNiI7P]$ Fe@$NiGP]l O00iganJc polyme! ~ubstlate
CUllent denbJty ~4/dm 2)
i
J
So-In On COppe! euBstr@te
Ifl!
_
16 ~ norpflou5 vlloy add
2)
OC-iron
0.5
Sulphate s o l u t i o n w;th H)BOj and o(@anic a d d i t i v e NiSOj.7H20 NiCI2.6HzO FeS04.TH20 N~ c i t r a t e NaH2PO2"H20 bacchazio
J-5
4 .7
~-tln
Zt
Ferromagnetic ~nd pwramagnetic amorphous a|loy6
]0
@iyc;t~
In this paper the following Lhe tabulated data.
new results will be lifted out of
A. Vdrtes, Corrosion protection attd electrochemical processes studied Io' M.S.
Electrodeposited
Fe-gr-Ni
alloys
The development of ternary Fe-Cr-Ni electrodeposits with a composition approximating to that of stainless steel has proved to be advantageous due to considerable wear, corrosion resistance, good adhesion and attractive appearance. Until recently only very thin layers could be obtained. The deposits examined in this paper were obtained using a new process which gives substantial deposition of thick layers ,~lth constant composition [25]. The main parameters of deposition are given in Table 4 and a more detailed description is available in the literature [22]. The N~ssbauer spectrum and its magnetic hyper[ine field distribution for one of the samples is given in Fig. 7/a and 7/b.
"
?+
i
'1 I
i
v~m/s)
2#
2o
3,0
H Oe
27
28
F i g . 7. M~ssbauer p a r a m e t e r s o f 18 % Cr, 29 % N i , 55 % Fe a ] ] o y a t room t e m p e r a t u r e . a) M~ssbauer s p e c t r u m o f e l e c t r o d e posited sample, b) High f i e l d conlponents o f Lhc hypecfine [leld distribution. c) NSssbauer s p e c t r u m o f t h e r m a l l y prepared sample.
+i +'',. r"--fl
"E "--
":
cll
-4 v (Om/.s.1.4
M6ssbauer s p e c t r u m o f th e t h e r m a l l y p r e p a r e d ( c a s t ) F e - C r - N i a l l o y w i t h t h e same c o m p o s i t i o n i s d e m o n s t r a t e d i n F i g . 7 / c . I t i s a d e m o n s t r a t i v e e x a m p l e t o what an e x t e n d t h e e l e c t r o d e p o s i t e d and c a s t a l l o y s can d i f f e r from each o t h e r . The c a s t sample i s p a r a m a g n e t i c and most p a r t o f t h e e l e c t r o d e p o s i t e d l a y e r was f e r r o m a g n e t i c . The r a t i o o [ t h e p a r a m a g n e t i c and f e r r o m a g n e t i c component depended o n l y s l i g h t l y on t h e c i r c u m s t a n c e s o f d e p o s i t i o n ( c u r r e n t d e n s i t y and c a t h o d e p o t e n t i a l ) . The f e r r o m a g n e t i c p a r t o f t h e s p e c t r a can be i n t e r p r e t e d as a
I 15
A. Vdrtes, Corrosion protection and electrochemical processes studied by M.S.
116
superposition of magnetically split s u b s p e c t r a o f Fe atoms i n different environments with neighbous alloying elements. This evaluation i s based upon a model i n w h i c h the e f f e c t of n e i g h b o u r i n g Ni and Cr atoms can be c o n s i d e r e d s e p a r a t e l y ~ . T h u s , t h e s p e c t r a o f F e - N i - C r a l l o y s can be c o n s i d e r e d as s p e c t r a of quasibinary Fe-Ni--Cr alloys, where t h e e f f e c t o f Ni atoms i s reflected by t h e m o d i f i e d f i e l d o f Fe i n c o m p a r i s o n to t h a t o f ~-iron. The s u b s p e c t r a , shown i n F i g . 7/b h a v i n g h y p e r f i n e fields HO, H1, H2 . . . ~7,2~ can be a s s o c i a t e d w i t h O, 1, 2 . . . n e i g h b o u r i n g Cr atoms r e s p e c t i v e l y . 8y d e t e r m i n i n g e i t h e r the area o f t h e s p e c t r u m l i n e or t h a t o f t h e peak o f t h e h y p e r f i n e f i e l d distribution, the concentration of the alloying e l e m e n t s can be estimated ~ . The p a r a m e t e r s o f t h e p r e s e n t f e r r o m a g n e t i c s p e c t r u m p a r t s as w e l l as t h a t o f t h e h y p e r f i n e f i e l d distribution are c o n s i s t e n t with the concentration of the deposited alloys. Electrochemically
deposited
Fe-P and F e - N i - P
amorphous a l l o y s
The c o r r o s i o n r e s i s t i v i t y o f t h e amorphous a l l o y s i s h i g h e r than that of the crystalline alloys. It is the origin of the increasing importance of the electrodeposited amorphous s u r f a c e layers. Fe84P16 and Fe. 9 ] P 7 samples were d e p o s i t e d on Ni s u b s t r a t e s by the prescription g i v e n ~n / a b l e 4 ~ . The N d s s b a u e r s p e c t r a and t h e i r h y p e r f i n e f i e l d d i s t r i b u t i o n s are d e m o n s t r a t e d i n F i g . 8 and F i g . ?.
z
9
D
,.
-..,.~.~ 9
:~'
,.,
15
23,
m
P(H)
.
w
- 4
Fig.
8.
0 +4 v(mm/s)
,9o
a) Room t e m p e r a t u r e N~ssbauer s p e c t r u m d e p o s i t e d F e ~ , ~ @ on Ni s u b s t c a t e , b) and i t s h y p e ~ field distribution.
27o H/kOe of
310
electrochemically
A. Vdrles, Corrosion protection and electrochemical processes studied by M.S.
23, !
~'.
, ~.
,' ,.-...
...,
;.:j~.
..~.'....
pIH)
r
o)
P,
9
-L vimOm/s)+,
260
290
,
,
w
~
320
,
,
350
H/kOe
Fig. 9. a) Room temperature M~ssbauer spectcum of electrochemically deposited F e ~ P ~ on Ni substrate, b) and its h y p e ~ i ~ e field distribution. The M~ssbauer r e s u l t s show t h a t F e ~ 4 P . . a l l o y has amorphous s t a t e w i t h t h r e e n o n - e q u i v a l e n t main i r o ~ p 6 ~ i t i o n . The amorphous p a r t i n F e ~ P ~ d e p o s i t i s o n l y 16 % and t h e main component i s ~-iron. )1 publication w r i t t e n by L i n e s g i v e s c o r r e l a t i o n s , on t h e one h a n d , b e t w e e n t h e h y p e r f i n e f i e l d and e f f e c t i v e c o o r d i n a t i o n number o f i r o n i n t h i s system and, on t h e o t h e r hand, b e t w e e n t h e e f f e c t i v e coordination number and t h e d i s t a n c e b e t w e e n t h e Fe and P atoms. On t h e b a s i s o f L i n e ' s d a t a i t was p o s s i b l e t h e e s t i m a t e t h e Fe-P d i s t a n c e s i n Fe P as 0 . 1 7 7 nm, 0 . 1 8 5 nm and 0 . 1 9 8 nm ~ . Fe-P and F ~ N } w a l l o y s were e l e c t r o d e p o s i t e d on o r g a n i c p o l y m e r s u b s t r a t e s as w e l l ~ . The main p a r a m e t e r s o f e l e c t r o d e p o s i t i o n a r e g i v e n i n T a b l e 4 and t h e M~ssbauer s p e c t r a i n F i g . 10 and F i g . 11. On t h e b a s i s o f t h e M~ssbauer s p e c t r a t h e f o l l o w i n g s t a t e m e n t s c o u l d be c o n c l u d e d :
9
;~.
7%
9
~
.:'
9
....9
7
.
;o
'
,.
9"
:,i
~
F i g . lO. Room t e m p e r a t u r e M~ssbauer s p e c t r a o f Fe-P electrodeposits on o r g a n i c polymer substrates. a) Fe92P 8
%,
D 0
t.)
9~ 5
,,..~
9
..
.'...*#- ....,t
";
~,.. ,
:
,
"..
*""
'- ,,,4~,
-~:.
'
6
-4
' +/-,
vlmm/s)
nl
b)
Fe87P13
117
118
A. Vdt'te;, Corrosion protection and electrochemical l;rocesses studied
9
,i
:,
9 '
by M.S.
.;
.
:"
h ~! '..: :
9 I:
[i ul
...... 9
...~. .~,
'' 0
b)
",i
0
Fig. ll. M6ssbauer s p e c t r a o f Fe-NL-P electrodeposits on o r g a n i c p o l y m e r substrates. S p e c t r a r e c o r d e d a t room temperature. a)
i!
" "
Fe43Ni45P12
b)
Fe68Ni17P15
c)
Fe83Ni8Pll
"'i" I
-Z
6 +L v(mm/s)
I h e L ' a t i o of" f e r [ ' o m a g n e t i c and p a r a m a g n e t i c components and a]s(~ the r a t i o o f c r y s t a l l i n e and amorphous p a r t s o f t h e d e p o s i t ~ ; e n . s i t i v e l y depend on t h e c o m p o s i t i o n o f t he d e p o s i t and depend ul~ly s l i g h t l y on t h e s u b s t t ' a t e ( c o m p a r e F i g . 8, 9 and 1 0 ) . ] h e Mcissbauer p a t t e r n s o f t h e e l e c t c o d e p o s i t e d samf~]es ace very different from t h o s e o f r a p i d l y quenched amorphous a l l o y s o f Lhe same c h e m i c a l c o m p o s i t i o n s ~0]. It demonstrates again that the s t t - u c t u r e o f ~he e l e c t [ ' o d e p o s i t e d a l l o y s can be v e r y d i f f e r e n t f[um t h o s e p r o d u c e d by m e t a l l u r g i c a l way. 5;t:udy o f i n t e r p h a s e f o r m a t i o n and m e t a l s u b s t r a t e s
at
the
interface
nf
eleetrodeposits
I f l t u c p h a s e f o r m a t i o n a t [he i n t e r f a c e of elects metal l a y u r arid s u b s t r a t e has a s t r o n g e f f e c t on t h e s t a b i l i t y and co[rosion resistivity o [ th e d e p o s i t 9 W i t h o u t i n t e [ ' p h a s e f o r m a t L o n , the e ] e c t v o d e p o s i t can be e a s i l y removed by m e c h a n i c a l f o r c e s . lf~terphase fo['mation a l s o i n c r e a s e s the c o r r o s i o n r e s i s t i v i t y of [l~e m e t a l s u r f a c e , f h e s e f a c t s make i t v e r y ~ m p o r t a n t t o s t u d y t h e j,lte[phn's~ for'marion between the e l e c t r o d e p o s i t s and s u b s t r a t e s . I n t e r f a c e sLudies between the e l e c t r o d e p o s i t e d t i n and meLal '.~,Jbstcate a r e g i v e n i n t h i s p a p e r to d e m o n s t r a t e how t h e NossDauer Lechr~ique can be used t o l e a r n new i n f o r m a t i o n a b o u t t he i n t e r faces between e i e c t r o [ s l a y e r s and s u b s t r a t e s . T i l l e v i c h e d i n 5 Sn/,( 85 ~) was e l e c t t - o d e p o s i t e d on b o t h s H r f a c e s o f t h i n (10 - 1 0 - ~ ~P~9sheets o f s u b ~ t r a t e s . The p l a ~ J n g s ~ l u t J o n c o n t a i n e ~ 2 5 3 g / d o " ~f S n ] . , 12 g / d o " NaOH, 1.5 q / d o CIl~COOIqa arid 1 cm / d o o f 5[I % Ho0~. Fhe~more d e t a i l e d p a r a m e t e r s uf>electroplating is g i v e n in th6 I i t e r a t u r e ~31-3a~ . The t h i c k n e s s o f t h e t i n h a y e r s were b e t w e e n 2 0 - 1 0 0 0 nm. An i n t e t p h a s e f o r m a t i o n t a k e s p l a c e i n most o f t h e s t ' u d i e d cases as i t i s shown i n T a b l e 5. A h e a t t r e a t m e n t o f the e] c c t r o d e p o s i t e d s a mples r e s uJ i, s tn an i~,crease ~)j t h e t h i c l < n e s s o f Ehe i n t e r p h a s e and s u c [ ; e s s i v e h e a t
A. Vdrtes, Corrosion protection and electrochemical processes stttdied by M.S.
Table 5 Tabulation o{ the results of M~ssbauer measurements on the interphases between the electrodeposited tin and substrates 5ubstrate~
Ir, terphase tormation
Humln|um
NO
Iron
Yes (moderate)
qlckel
Yes (strong)
A c t i v a t i o n energy of I n t e r d l t r u s i o n ( [ a ) . kJ/mOl
HOssbauer parameters
Compo~jhon Ot the |.terpha@e
R,fa/~ m
or "mm.~ "1
Rete(ence
AE,"Wmm.s - | ?
:opoe(
Yes (moderate)
hl~et
Yes (strong)
)lot)hum
NO
70
lg
-4
Fe)Sn 2 u 2
Ig2,332
XISn X | }Sn 4
2.8
CuGEn5 Cu)Sn
3.5
g.6 2, }8 2,7g
~, I, 5
1.90
g.8-g.92
2, 6
2,g2
2.16 1,74 @, 9
2.25 7.1S
Solid soluhon AgjSn
I~.5*2
1.92 I 3) 2.50
A l l o y with mmeml
126.2~2
g.7-g,8
2 . 1 0 - 2 . )0
14.5
t.ln-plat Inua
atomic r a t i o 9 fa end ~ are the g e b y e - h l l e r h c t o r s of the Intsrphase and # - t i n r e s p e c t i v e l y . "Wls(,m@[ s h i f t r e l a t i v e to CaSngj. "9 splitting. 9WrWlnterphase ( a l l o y ) tormatlon look o l l c e o n l y e~ e r e s u l t of heal treatment in the temperature range of )7)-~85 K.
treatments and M~ssbauer measurements can serve also the activation energy of the interdiffusion (interphase formation). Some demonstrative results of the M~ssbauer studies are given in Fig. 12, Fig. 13 and in Table 5.
" ~ ~ ' ~ ,
I
C
2~"
0
9 ~./
31, 34
|
32,
.
31 ,
34
""
33,
34
34
~ '"
-1 0
.......... ~';~"
+2
+4
33,
vlmm/s) Fig. 12. M~ssbauer spectra of a Sn/Ni sample. 515 nm electrodeposited Sn on Ni recorded at 295 K. Ootted line: ~-Sn, full line: Ni-Sn alloy, i. prior to heating, 2. heat treated at 413 K for 30 minutes 3. at 433 K for 30 minutes.
119
A. Vdrtes, Con'osion protection and electrochemical processes studied by M.S.
120
(1/R1) xlO~ 2.5
3.0
3.5
F i g . 15. D i [ f u s i o n data of the investigated tin-substrate s y s t e m . The e x p e r i m e n t a l d a t a suggest that the combination of t h e p a r a b o l i c la w and o f t h e A r r h e n i u s e q u a t i o n i s a good approximation of the descript i o n o f t h e phenomenon. Namely: 2 E a ' where x i s in ~ x = i n O'o RT
- 28
- 30
-32 -34
the t h i c k n e s s of the i n t e r phase o b t a i n e d from t h e MSssbauer s p e c t r a and At is the time of the heat t r e a t m e n t .
-36 .
_.c_
Chemical
-
"%~p!
reactions
on e l e c t r o d e
surfaces
(Passivation) The p a s s i v i t y o f e l e c t r o d e s due t o a more o r l e s s compact s u r f a c e f i l m f o r m e d e i t h e r as a r e s u l t o f c h e m i c a l o x i d a t i o n (air, oxidizing a c i d s ) or by a n o d i c p o l a r i z a t i o n of the m e t a l . Emission or t r a n s m i s s i o n i n s i t u M~ssbauer s p e c t r o s c o p y can g i v e d i r e c t information a b o u t t h e c h e m i c a l c o m p o s i t i o n and a b o u t t h e mechanism of the formation of the passive films. I n t h e case o f e m i s s i o n o r t r a n s m i s s i o n t e c h n i q u e r a d i o a c t i v e o r e n r i c h e d s t a b l e MSssba.uer a c t i v e i s o t o p e , r e s p e c t i v e l y , should be d e p o s i t e d on t h e s u r f a c e o f e l e c t r o d e . For t h e t r a n s m i s s i o n g e o m e t r y , t h e e n r i c h e d i s o t o p e s h o u l d be d e p o s i t e d on t h e s u r f a c e o f a v e r y t h i n s u b s t r a t e o f low a t o m i c number ( e . g . A1, Be) b u t t h e t h i c k n e s s o f t h e s u b s t r a t e has n o t any e f f e c t on t h e M~ssbauer spectra if the emission technique is applied. Some d a t a c o l l e c t e d by M~ssbauer s p e c t r o s c o p y a r e g i v e n i n T a b l e 6. A t y p i c a l p a s s i v a t i o n c u r v e , t h e scheme o f an i n s i t u measurements and a MSssbauer s p e c t r u m , r e c o r d e d i n s i t u , a r e shown i n Fig. 1 4 , F i g . 15 and F i g . 16. t ~ e i n s i t u M6ssbauer s p e c t r u m gave e v i d e n c e o f t h e p r e s e n c e o f Sn lvTaS w e l l ~ w h i l e t h e ex s i t u m e a s u r e m e n t s c o u l d . d e t e c t o n l y Sn f o r t h e same system due t o t h e o x i d a t i o n o f Sn I d u r i n g the t r a n s l o c a t i o n o f t h e sample from t h e e l e c t r o c h e m i c a l cell i n t o t h e MSssbauer s p e c t r o m e t e r ~ .
A. Vdrtes, Corrosion protection att(I elec'/rochemical processe,~ studied by M.S.
Table 6 Tabulated [lectrode
in situ
M6ssbauer
4 p p l i e d p o t e l t t l a l attd lefelence electlnde
57Co
-100 .200 ,SnO 9BOO
Fe
mY, mY, mY, mY,
SC[ 5C[ SCE SCE
9 600 mY,
NH[
of i
cesults
on e l e c t r o d e
Cnmpo~itlolt the .~nlutzo,I
pH
bnlate buffer bnzate b u f f e t hnlat~ hH|fnl
0.5 R.5 R,5
botate ho|[el
R.5
O.iSN b n I I c
acld *
passivation
Composition of the pabslee f i l m r 2 ~-CoOOH ~L.-ConOH 4 CoO2
R.~
amorphous, p o l y m e r i c lion oxyhzdIoxlde after
drying:
paramagnetlc -l}00
mY,
RHE
hniate
huffel
57
~-Co00H
bOdlum b o i d t e
fe
Refelences
R.~
J }B
supel~'-Fe20 }
s ma l l p a r t i c l e s
of 59
zlon oxides z
Fe
alkaline
solution,
amorphous lion-oxide
l}.O
* O.OSH K2520 A I
*65N mY,
SCE
I
Fe
B.4
oC-Fe30 } 41
I
I
0 . 5 H CH}C00Na ~n 95 wt~ CH}C00HI|n the pzesence Of 02
Fe(CH}KO0)I.xt0H} x
42
I *400 mY,
NHE
80 wt% H2S04 t = 50 ~
*900 mY,
NH[
B0 wt% H2504 t = 50 ~
*1500 mY,
Sn
0.ISN hollo acid * sodium h o l a t e * l.}xlO -2 X XaCl
-300 mV to *200 mY, SCE I
Steel
40
I
Fe
Fe
i
NHE
hydrated Fe(ll)-su]phate
Fe{l|)-
hydrated and F e ( l l l } sulphate
hydrated Fe(]lI)-sulphate
80 wt~ H2SO4 t = 50 ~ 3.0
Fe(|l)-phosphate
}.0
o n l y Fe }+ d o u b l e t . nO s t o l c h i o m e t T i c
anodlcally pole[lied ; n the a c t i v e l e g i o n
phosphate b u f f e t
anod~cally polazlzed I n the p~ssJve r e g i o n
phosphate b u f f e K [POk } " ] = 0.15 X
-1180 eV to
boxate buffet
8.A
SnO2 or Sn(AH)I * amo~phoub Sn(nH) 2
borate buffet
8.4
Sn02 or Sn(0H) A
-780
mY,
-760 *200
mV to mV, 5CL
[P04}'J
= 0.15 H
o x i d e phases
5CE
5CE = s d t u l a t e d calomel e l e c t r o d e NHE = nolmal h v d l o f l e n e l e c t l o d e
4}
44
121
122
A. Vdrtes, Corrosion protection and electrocllemical processes studied by M.S.
~A Sn 9 V/win
f: F;~OmV~-gOOmV,) 2. f4~mV~oSOOmV.I
*4
~ "
I
r
-2
I
/
,80
,120 II I;
-4
F i g . 14. P o t e n t i o d y n a m i c curves recorded at scanning r a t e of 3.6 V min on t i n in b o r a t e b u f f e r . The maximum v a l u e of p o l a r i z a t i o n i s i. -900 mY, 2. +500 mY. f-
5
F
D
E
"-D
C
Q]
b]
F i g . 15. ( a ) In s i t u Mbssbauer c e l l : (A) gas i n l e t - o u t l e t ; (8) p l a t i n u m c o u n t e r - e l e c t r o d e ; (C) magnetic s t r i r r e r ; (D) specimen; (E) Luggin c a p i l l a r y ; (F) t h r e e - w a y sLop-cock; (G) to r e f e r e n c e electrode (sce), (b) Specimen compartment.
/I. Vc;rtes, Corrosion protection uttd electrochemical processes studied by M.S.
9 ;
s -'" "
"v-'" " : " . . ' . . ' . . .
. . . . .
"
,v 9
-:'" ...."
123
.. ! '" 9 " "
',
" .'
-
.
-. -.;.!.5' --
{ -
-
i
o ' v ~nml$)
+2 '
+4
'
F i g . 16. MSssbauer s p e c t r u m o b t a i n e d d u r i n g [~0 mV p o l a r i z a t i o n i n b o r a t e b u f f e r on Sn e l e c t r o d e d e p o s i t e d on a l u m i n i u m . Conclusion The shown e x a m p l e s d e m o n s t r a t e that the M S s s b a u e r effect is an e x c e l l e n t tool for c o r r o s i o n and e l e c t r o c h e m i c a l research and technique. This method can give i n [ o v m a t i o n about tile chemica] c o m p o s i t i o n and a b o u t t h e c r y s t a l l i n e and m a g n e t i c s t r u c t u r e o f t he f o l l o w i n g systems i f t h e y c o n t a i n M~ssbauer a c t i v e e l e m e n t s . Covvosion products. Corrosion protective d e p o s i t s and s u r f a c e l a y e r s . Intevphases at the interface of the c o r r o s i o n p r o t e c t i v e l a y e r s and s u b s t v a t e . Electcodeposits. I n t e c p h a s e s between e l e c t c o d e p o s i t s and s u b s t c a t e s . P a s s i v e l a y e r s on e l e c t r o d e s . Electrode surfaces in galvanic cells.
The M~ssbauer t e c h n i q u e can be used [ o r t h e s t u d y o f t h e c h e m i c a l p o s i t i o n o f N~ssbauec a c t i v e i o n s i n t r o d u c e d i n t o c o r r o s i o n protective o r g a n i c p o l y m e r s . T h i s method h e l p s us to l e a r n more a b o u t t h e c h e m i c a l bonds b e t w e e n m e t a l s and o r g a n i c c o a t i n g s . Acknowledgement Most o f t h e d e m o n s t r a t e d r e s u l t s were c a r r i e d o u t i n a c o o p e r a t i o n w i t h P r o f . Dr. H. L e i d h e i s e c o f L e h i g h U n i v e r s i t y , USA. A p a c t o f the r e v i e w e d measurements were made w i t h Or. H. Mehnec of C e n t r a l Research I n s t i t u t e for Physical Chemistry, Berlin, GOR. My c o l l e g u e s : I . C z a k 6 - N a g y , M. V a r s A n y i - L a k a t o s , E. Kuzmann a l s o t o o k p a c t i n t i l e above s t u d i e s . All of these contributions are h i g h l y a p p r e c i a t e d .
124
A. V#rtes, Corrosio. protectio, a . d electrochemical processes studied by M.S.
References
~ ~ ~ ~ ~ ~
D4 ~ ~ ~ ~ ~ B~ ~ ~ B~ B~ ~ ~ ~
I. O@zsi, A. V@ctes, L. Kiss: Magy. K@m. Foly6irat, 73(1969)421. T. Peev, K.M. Geocgieva, 5. Nagy, A. V@rtes: Radiochem. Radioanal. Letters, 33(1978)265. P.C. Bhat, N.G. Puttaswamy, R.M. Mallya: Radioohem. Radioanal. Letters, 52(1982)299. T. Peer, A. Vertes, G.M. Jovkov, S. Nagy: Radiochem. Radioanal. Letters, 46(1981)405. H. Leidheisec, Jr., A. V@vtes, I. Czakb-Nagy, J. Farkas: J. Electvochem. Soc. 134(1987) 825. H. Leidheiser, Jr., I. Czak6-Nagy, A. V4ctes: J. Electvochem. Soc. 134(1987)1470. A. Vevtes, L. Korecz, K. Burger: MSssbauev Spectroscopy, pp. 265-280, Elsevier Publishing Co, Amsterdam-Oxford-New York (1979). F.M. Friedt, L. Arch: Radiochim. Acta, 12(1969)208. A. V@rtes, A. Czir~ki, I. Czakd-Nagy, H. Leidheiser, Jr.: Accepted for publication in J.Electrochem. Soc. A. V@ctes, I. Czak6-Nagy, P. Oeck, H. Leidheisev, Jr.: J. Electvochem. Soc., 134(1987)1628. A. V@vtes, A.P. Pchelnikov, V.V. Losev, M. Suba, M. Vavs~nyi-Lakatos, I. Czak6-Nagy: Radiochem. Radioanal. Letters., 53(1982)167. I. Ja@n, M.L. Vars~nyi, E. Kov@cs, I. Czak6-Nagy, A. 8uz@s, A V@~tes, L. Kiss: s Aria, 29(1984)1119. O Oa@n, A. V@ctes, K.M. Tjutina, L.V. Kasmodamianskaya, L Kiss, R.V. Shepeleva: Electrochim. Acta, 30(1985)535. H Leidheiser, Jr., A. V@rtes, I. CzakS-Nagy, M.L. Vars6nyi, I de Physique, 41(1980)C1-351. J Jaen, A. Pasovsky, G. Raichevsky, I. Czakd-Nagy, L. Kiss, A Vevtes: Radiochem. Radioanal. Letters, 58(1983)Ii1. H Leidheiser, Jr.,A. Vevtes, M.L. Vars~nyi: J. Electroohem. 5oc., 128(]981)1456. H. Leidheiser, Jr., A. V@rtes, I. Czak6-Nagy, M.L. Vars~nyi: J. de Physique, 41(1980)Ci-351. H. Leidheise~, Jr., A. V@Ftes, M.L. Vavs~nyi, I. Czakd-Nagy: J. Electrochem. Soc., 126(1979)391. R.L. Cohen, K.W. West, M. Putler: J. Electvochem. Soc., 124(1977)342. R.L. Cohen, F.8. Koch, L.N. Sohoenberg, K.W. West: J. de Physique, 41(1980)CI-349. H. Mehner, J. 3uh@sz, M. Suba, A. V@rtes: Radiochem. Radioanal. Letters, 56(1982)57. A. V@rtes,A. Watson, C.U. Chisholm, I. Czak6-Nagy, E. Kuzmann, M.R. El-Sharif: Electrochimica Acta, V.32, 12(1987)1761. E. Kuzmann, A. V@rtes, L. Kiss, G. Raichewski, S. Vitkova: Accepted [or publication in Electrochimica Acta. A. V@vtes, A. Pashovski, O. Raighevski, I. Todorov, I. CzakS-Nagy: Acta Chimica Hungarica, 124(1987)633. A. Watson, C.U. Chisholm, M.R. Ei-Sharif: Trans. Inst. Met. Finish, 64(1986) J.M. Genin, O. Le Caiv, P.H. MaitFepierre, 8.J. Thomas: ScFipta Met., 8(1974)15. M.8. Stearns: Phys. Rev. 813(1976)1183. I. Vincze, I.A. Campbell: O. Phys. 3(1973)647. E. Kuzmann, R. Oshima, F.E. Fujita: O. Jap. Inst. Metals, 151(1979)
A. Vdrles, Corrosion proleclion and eleclrochemical processes sludied I)y M.S.
~ ~ ~
~ ~ ~ ~@ ~ ~ ~ ~ ~
~ ~
E. Kuzmann, A. V@rtes, S. V i t k o v a , G. R a i c h e w s k i , L. K i s s : E l e c t r o c h i m i c a Acta, Submitted f o r p u b l i c a t i o n . A. V ~ r t e s , S. Nagy, M.Z. Awad: Nuc1. I n s t r . Methods, 199(1982)367. H. Mehner, A. V@rtes: O. R a d i o a n a l . Nucl. Chem., 89(1985)153. H. Mehner, A. V e r t e s : O. R a d i o a n a l . NucI. Chem. L e t t e r s , 96(1985)353. A. V@rtes, H. Mehnec, S. Nagy: J. Radioanal. Nucl. Chem. Articles, 111(1987)283. M.L. Vars@nyi, O. Ja@n, A. V@rtes, L. Kiss: E1ectrochimica Acts, 30(1985)529. A. V@rtes, H. Leidheiser, Jr., M.L. Vars@nyi, 6.W. Simmons, L. Kiss: J. Electrochem. Soc., 125(1978)1946. B.W. Simmons, E. Kellerman, H. Leidheiser, Jr.: J. Electrochem. Soc., 123(1976)1276. W.E. O'Grady: J. Electrochem. Sot., 127(1980)555. O. Eldridge, M.E. Kordesch and R.W. Hoffman: D. Vac. Sci. Technol., 20(1982)934. Yu.Yu. Esipenko, A.M. Suhotin: Zashchita Metallov, 23(1987)1053. M.C. L i n , R.6. Barnes, T.E. F u r t a k : AlP Con[erence P r o c e e d i n g s No. 84, E d i t e d by: F.C. Schwerer, American I n s t i t u t e of P h y s i c s , New York, 1982. G.N. Markosyan, L. 5 z i r ~ k i , A . I . Molodov, L.M. Vars@nyi, V.V. Losev, J. Ja@n, A. V@rtes, L. K i s s : E l e k t r o h i m i y a , 22(1986)219. F.H. Chibirova, T.V. Revina, V.A. Makarov, S.I. Reiman: Zashchita Metallov, 18(1982)905. U. Stumm, W. Meisel, P. 6Utttich: Hyperfine Interactions, 28(1986)923.
125