Millisecond studies of the birth of the cathode process in nickel plating

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MILLISECOND STUDIES Og THE BIRTH

21 IS !

CATHODE PROCESS IN NICKEL PLATING

By L o w e ll Max Magner

S u b m itted to t h e f a c u l t y o f th e G raduate S c h o o l i n p a r t i a l f u l f i l l m e n t o f t h e r e q u ir e m e n ts f o r th e d e g r e e , D o cto r o f P h ilo s o p h y , i n t h e D epartm ent o f C h em istry , In d ia n a U n i v e r s it y O ctob er 1949

ProQ uest Number: 10295190

All rights reserved INFORMATION TO ALL USERS The quality o f this reproduction is d e p e n d e n t up on th e quality o f th e c o p y subm itted. In th e unlikely e v e n t th at th e author did not sen d a c o m p le te m anuscript an d th ere are missing p a g e s , th e s e will b e n o ted . Also, if material h a d to b e r em o v ed , a n o te will in d ica te th e d eletio n .

uest ProQuest 10295190 Published by ProQuest LLC (2016). Copyright o f th e Dissertation is held by th e Author. All rights reserved. This work is p r o te c ted a g a in st unauthorized co p y in g under Title 17, United States C o d e Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106 - 1346

ACKNOWLEDGEMENT

I t IS a p le a s u r e t o r e c o r d my th a n k s t o P r o f e s s o r PTank 0 . M ath ers f o r h i s en co u ra g em en t o f o r i g i n a l and in d e p e n d e n t i n v e s t i g a t i o n . The f i n a n c i a l a s s i s t a n c e o f t h e Du P ont P o s tg r a d u a te f e l l o w s h i p and t h e A ll U n i v e r s it y P o s tg r a d u a te f e l l o w s h i p i s h e r e b y a ck n ow led ged w it h th a n k s . W ith o u t t h e lo a n o f e l e c t r o n i c eq u ip m en ts from P r o f e s s o r 3?V T, Gu ok er *s Army C hem ical Be s e a r c h Group, t h i s r e s e a r c h w ou ld n o t h a v e b e e n p o s s i b l e .

P a r tic u la r

th a n k s a r e due Mr, A, H, P e t e r s o n f o r h i s many s t im u la t in g d i s c u s s i o n s o f v a r io u s a s p e c t s o f t h i s r e s e a r c h .

ABSTRACT

A t e c h n iq u e i s d e s c r ib e d w hereby change© i n th e p o t e n t i a l o f a c a th o d e ( v e r s u s h a l f * c e l l )

are o b serv ed

f o r th e f i r s t few m i l l i s e c o n d s a f t e r t h e i n i t i a t i o n o f a co n sta n t cu rren t e l e c t r o l y s i s . The work r e p o r t e d d e a ls w it h a common n i c k e l s u l f a t e p l a t i n g b a th and th e e f f e c t s o f some o f t h e common v a r i a b l e s on t h e 11b ir th * 1 p r o c e s s .

I t i s s i g n i f i c a n t t h a t , f o r m ost

p r a c t i c a l c u r r e n t d e n s i t i e s , th e p o t e n t i a l o f t h e c a th o d e i s more n e g a t i v e a fe w m i l l i s e c o n d s a f t e r t h e c u r r e n t i s s t a r t e d th an i t w i l l b e t h i r t y s e c o n d s l a t e r ,

The m a g n itu d e

o f t h i s *♦o v e r sh o o t* b eyon d t h e e v e n t u a l o v e r v o lt a g e v a lu e i s a p p r o x im a te ly 0 , 1 v o l t , A m ethod o f i n t e r p r e t i n g t h e v o l t a g e - t i m e f u n c t io n i n term s o f an e l e c t r i c a l l y e q u iv a le n t RO n etw o rk i s a d v a n ced , A s ta n d a r d , c a p a c ita n c e in p u t , s i n g l e sw eep ty p e c a th o d e ra y o s c i l l o g r a p h (Dumont ty p e 2 4 7 ) , an e l e c t r o n i c s w it c h (Dumont ty p e 185A) and a E a i r c h i l d O s c i l l o R ecord Camera { Dumont ty p e 514} a r e th e m ain com ponents u t i l i s e d .

i s s rx Z» 'fas O B JE C T IV E

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p.

2

WM j?HE»;KESUXiTS ,■AHD THEIB IHTI.RPBKTATION V . TBS ASPKiTDICKS O^DATA

p . 10

a fte r p .

IB

I .

I.

Tfre O b j e c t iv e

. ■■■■■' . : ■ 1 The p u r p o se o f t h i s re©e& rch was to d e v e lo p a

s u i t a b l e "one shot?*, n o n * * r e p e titiv e t e c h n iq u e f o r o b s e r v in g t h e v o lt a g e * t im e r e l a t i o n s h i p o f a p r a c t i c a l e l e c t r o p l a t i n g p r o c e s s d u r in g i t s

e a r lie s t sta g e s.

In

e s s e n c e , t h e r e f o r e , th e t e c h n iq u e to b e d e v is e d was o n e f o r w a tc h in g th e “birth** o f an e l e c t r o d e p r o c e s s by o b s e r v in g t h e e l e c t r i c a l ch a n g es a t t h e e l e c t r o d e - s o l u t i o n in te r fa c e . Once t h e t e c h n iq u e was d e v is e d , th e e f f e c t s o f some o f th e common e l e c t r o p l a t i n g v a r i a b l e s on t h e v o l t a g e - t i m e r e l a t i o n s h i p w ere t o b e o b s e r v e d . I f p o s s i b l e , a s im p le , s e m i - q u a n t i t a t i v e i n t e r p r e t a t i o n o f t h e r e s u l t s was t o b e a d v a n ced . The a b o v e o b j e c t i v e s h a v e b een r e a c h e d f o r t h e c a s e o f n i c k e l d e p o s i t i o n from a common s u l f a t e p l a t i n g b a th . II.

The L i t e r a t u r e

To th e a u th o r ’ s k n o w led g e, t h e r e i s no r e c o r d a v a i l ­ a b le o f any su ch ty p e e x p e r im e n ts a© w i l l b e d e s c r ib e d . The r e c e n t r e v ie w s o f e l e c t r o d e p r o c e s s e s p r o v id e an 1 g a r a day ~ S o c , Sp jecu a a ^ ^

I-""- *’ K le ctro 'd e Pr cTcelTs Sis’41

2 H ic k lln g , A. 11The M echanism o f E le c t r o d e P r o c e s s e s i n A queous S o lu tio n s * 1 Q u a r te r ly R ev iew s 2 9 5 -1 2 5 (1 9 4 9 ) e x c e l l e n t in t r o d u c t io n t o w hat h a s b e e n done i n t h i s g e n e r a l

a* fie ld

o f xm u*arch* tw o s t a n d a r d w o r k s c o n c e r n i n g i n t e r l a c i a l p h en o m en a

& Adam, ff, K , The P h y s ic s o f c E ^ i B t r y and S u r fa c e s 2nd ecL O x fo rd , T I9 S 8 ) 4 , B u t l e r , J^A ,!!, E l e c t r o c a p f I l a r i t v C hem ical P u b lis h in g Co, If, Yf (1 9 4 1 ) p r e s e n t no h in t© o f th e e x i s t e n c e o f e l e c t r o d e p o t e n t i a l o V e r sh o o ts n o r do th e y g i v e any e x p la n a t io n o f t h e v a r io u s phenomena i n term s o f B. C, t r a n s i e n t a n a ly s is * P r o f e s s o r F e r g u so n * s b r i e f m en tio n o f o b s e r v in g c u r r e n t o v e r s h o o t s w it h h y d ro g en on p la tin u m c a th o d e s i s

t h e o n ly

5 P e r m s o n * ~A*Y, F a r a t e ............................................. ..1 9 4 7 7 " 'i

* E le c t r o d e P r o c e s s e s 11 p , 53* p laC e t h i s a u th o r c o u ld d is c o v e r p r e v io u s m en tio n o f th e ty p e o f phenomenon w h ich i s so common f o r t h i s n i c k e l s o lu tio n ,

T h is w r i t e r f e e l s t h a t t h e ” a c t i v e m a te r ia l*

and * e q u ilib r iu m a t a l l tim e s* e x p la n a t io n u se d b y F erg u son f o r th e h yd rogen e l e c t r o d e * s o v e r s h o o t i s

e n t i r e l y in a d e ­

q u a te to e x p la in th e phenomena o b s e r v e d w it h n i c k e l . F u rth erm o re, F erg u so n ig n o r e d t h e e f f e c t o f what m ust b© a c a p a c it a n c e o f l a r g e s i z e e x i s t i n g a t t h e i n t e r f a c e , III,

The T ech n iq u e

A, E le c t r o d e s and E l e c t r o l y s i s G e ll The e l e c t r o l y s i s c e l l was a sta n d a r d 250 m l, p y r e x beaker.

Around t h e i n s i d e o f t h e b e a k e r w ere p la c e d s t r i p s

ojP

pur® ^leatroJL-rti©

T h ese w ere p la c e d i n su ch

■a m anner t h a t th e b e a k e r was e s s e n t i a l l y lim e d w it h a s le e v e o f n ic k e l,

T h is n i c k e l l i n i n g s e r v e d a s t h e anode

f o r a l l e x p e r im e n ts , w it h c l e a n in g a t a p p r o p r ia te t im e s , The c a th o d e c o n s i s t e d o f a p i e c e o f p u re n i c k e l t u b in g , 0 ,1 2 6 * * o * d ,

In o rd er to e l im i n a t e e f f e c t s o f

e d g e s , a g l a s s h ea d was s e a l e d on t h e end o f t h e tu b e . In o r d e r to h a v e a d e f i n i t e a r e a e x p o s e d , t h e n i c k e l tu b in g w as p la c e d i n a t i g h t f i t t i n g g l a s s t u b e .

Thus o n ly t h e

a r e a b etw een t h e h ead and t h e g l a s s tu b in g w as e x p o se d to th e s o lu t io n ,

An a l t e r n a t i v e and e a s i e r m ethod i s to u s e

s u r g i c a l ru b b er tu b in g a s a m asking a g e n t , p la c in g a g l a s s p lu g i n t h e open end o f t h e tu b in g w h ich i s i n t h e s o l u t i o n a t t h e lo w e r end o f t h e e l e c t r o d e ,

I n a l l exp erim en t® a

c a th o d e a r e a o f 0 , 4 3 sq u a r e in c h e s w as u s e d , A sta n d a r d c a th o d e c l e a n in g p r o c e s s c o n s i s t e d o f a m ild w ir e b ru sh tr e a tm e n t (m o to r d r iv e n ) f o llo w e d by a w a te r w a sh in g and th e n an e t h e r d e g r e a s in g . I t i s b e l i e v e d t h a t a r e p r o d u c ib le e l e c t r o d e g e o m e tr y , su ch a s t h e d e f i n i t e an o d e and c a th o d e r e l a t i o n s h i p d e s c r ib ­ ed a b o v e , s h o u ld be u s e d f o r e x p lo r a t o r y e x p e r im e n ts o f t h i s typ e*

H ow ever, d u r in g e a r ly e x p e r im e n ts w it h o n ly

two n i c k e l s t r i p s f o r e l e c t r o d e s t h e * o v e r s h o o t 4* phenom ena w ere o b serv ed * B , The R e fe r e n c e H a lf C e ll The h a l f c e l l u s e d was a s ta n d a r d ty p e 0 ,1 H c a lo m e l

h a lf c e l l .

A'ftltift b r i% # f c o n t a in in g an a g a r g e l o f

0 * 1 if KOI i n one a m :ahd a s o l u t i o n i d e n t i c a l to t h a t o f th© p l a t i n g b a th b e in g i n v e s t i g a t e d i n t h e o t h e r arm, w as u s e d f o r a lm o s t a l l e x p e r im e n ts r e p o r t e d h e r e in . However* a fe w exp erim en t© w ere c a r r ie d o u t i n i t i a l l y w it h o u t a s a l t b r id g e .

Ho d i f f e r e n c e i n r e s u lt® was

o b ta in e d when i d e n t i c a l e x p e r im e n ts w ere c a r r ie d o u t w it h o r w ith o u t a s a l t b r id g e ,

Even s o , i t

i s r e com-

mended t h a t a © a lt b r id g e b e u se d i n o r d e r t o a v o id c r i t i c i s m from t h a t s o u r c e a s w e l l a s to h e lp 2ce«p t h e h a lf c e l l fr e e of fo r e ig n io n s . S in c e t h e in p u t r e s i s t a n c e o f t h e Dumont t y p e 1 8 5A E l e c t r o n i c S w itc h i s o n ly 100*000 ohm© i t w as n e c e s s a r y t o Enow th e i n t e r n a l r e s i s t a n c e o f a h a l f c e l l - n ic h e ! ca th o d e c o u p le .

By m ea su rin g th e open c i r c u i t p o t e n t i a l

d i f f e r e n c e w it h a 10 megohm v o lt m e t e r (BOA Model 195A V o lto h m y st) and th e n lo a d in g th e c o u p le w it h a p r e c i s i o n v a r i a b le r e e l© t o r (1OQC0G ohm H e lip o t ) u n t i l one h a l f t h e open c i r c u i t p o t e n t i a l i s m ea su red , th e i n t e r n a l r e s i s t a n c e o f th e c o u p le can b© e s t im a t e d t o w it h in a fe w p e r c e n t*

By t h i s m ethod th e i n t e r n a l r e s i s t a n c e o f

a h a lf - * c e ll n i c k e l c a th o d e c o u p le was fo u n d to b e 1 6 ,0 0 0 ohm s.

When a s a l t b r id g e i s in t e r p o s e d b etw e en th e h a l f -

c e l l and t h e e l e c t r o d e th e r e s i s t a n c e was in c r e a s e d t o 2 6 ,0 0 0 ohms, Thu© any v o l t a g e c a l i b r a t i o n d ep en d en t on s u b s t i t u t i n g

s*

a lo w r e s i s t a n e e sta n d a r d © a ll (2 5 * 50 ohms) f o r th e h i g h r e s i s t a n c e c o u p le n e e d s t o em ploy c o r r e c t i o n fa c to r © o f 1*16 and 1 ^ 6 f o r th e no b r id g e o r b r id g e c o n n e c t io n r e s p e c t i v e l y , The e x p lo r in g t i p o f t h e h a l f * c e l l o r s a l t b r id g e wad a lw a y s p la c e d a s c l o s e a g a i n s t t h e c a th o d e s u r f a c e as p o s s ib le ,

if

t h i s was n o t d o n e, * in s t a n t a n e o u s 11 IE

d rop s w ere reco rd ed #

H ence one c o u ld t e l l i f

some

a c c id e n t had moved t h e e x p lo r in g t i p away from t h e e l e c t r o d e in t e r f a c e # G* The K l e e t r i c a l C onnection© and P r o c e d u r e The e l e c t r i c a l c o n n e c t io n s w ere made a c c o r d in g t@ F ig u r e 1# F ig u r e 1 . t y Pg

c fo -n o V f~^

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S1N*G* s i g n a l s a r e o b s e r v e d no d e f l e c t i o n i s

ob served *

A lso i f s lo w ly ch a n g in g D.C* t r a n s i e n t s a r e o b s e r v e d , th e in p u t c a p a c it a n c e i s g r a d u a lly ch a rg ed and th e t r a c e m oves a b o u t on t h e o s c i l l o s c o p e screen *

T h e r e fo r e i t i s n e c e s s a r y

t o e s t a b l i s h a r e f e r e n c e l e v e l (g r o u n d i n t h i s c a s e )

and

compare t h i s v e r y f r e q u e n t ly w ith th e s i g n a l b e in g o b served * T hus, ev en th o u g h th e

D*C* in p u t l e v e l ch a n g es we h a v e a

r e f e r e n c e w h ich w i l l show t h o s e ch a n g es c o n tin u o u s ly * sw eep s p e e d s o f a p p r o x im a te ly 1 /6 0 s e c o n d , no change i n

At

aa F ig u r e Z s h o u ld b e i n t e r p r e t e d a s f o l l e w s a (X )

f i i e s p a c in g b e tw e e n l i n e s M 1 mad BB i s

th e ne

c u r r e n t# s t a t i c e l e c t r o d e p o t e n t ! e l * W

Is

t h e gn un d r e f e r e n c e l e v e l * ( z ) T r a c e AE r e p r e s e n t s t b s b i r t h o i t b s e l e c t r o d e p o la r is a tio n #

i« e »

t h e e l e c t r o d e i s h ecem im g

more negative with time a lte r the a ta ri ©1 & c o n s t a n t c u r r e n t th r o u g h i t *

Wot i c s t h e l a s h

o f auy i n s t a n t a n e o u s ch a n g e a t t h e b i r t h c l the process* (5 )

Point A represents sere time*

The s p a c in g b e tw e e n t r a c e s BB a n d AB a t

a^r

tim e r e p r e s e n t s t h e v a l u e c l t h e e l e c t r o d e p o t e n t i a l a t t h a t t im e m ea su re d a g a i n s t a % *! W* c a lc a n e i h&Xi c e l l *

(4) m e ©pacing between lin e s £€ and C*C* repre* se n t© the steady electrode p o t e n t i a l ©iter

30 seconds current passage* {&} The i n t e r v a l m arked on t r a c e BB l a 1 /6 0 0 seco n d .

T 3 0 0

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o r d in a r ily o b serv ed in

t h e s e e x p e r im e n t s *

The P h o tograp h y ^Th© m an u f& etu rer*a d i r e c t i o n s w ere f o llo w e d f o r u s in g th e F a ir c h i l d i s o | l l s Be c o r d C am ra to r e c o r d o i a g l s n©n**r©ourrsitt t r a n s le is t s *

The c a th o d e r a y tu b e was a

ty p o 5 CEP 1 1 1 w h ich was agfpeeissuXy do s ig n e d f o r j& o to g ra p & ic »&#©*

t h e f i l m u se d m m -Xawtmsn Buper IX iiAthoiigh M n a g ra p h

Pan w ou ld be b e t t e r f o r f a s t e r phenomena*

i t mam fo u n d

t h a t *M & ev#r ff& eest lo a d e d f ir m and - b r ig h t i n t h e v i ew er, no d i f f i e u l i y vtaur sne-sm xifsrsd i n p h o to g r a p h !n g t&tt% ev en at-openings; lees than the marimuai iMeli. the f 1 m * ;-allow #d*

Bapa*

Tim f i l m m m p r o c e s s e d a c c o r d in g t o

m&anJTastiirer** d i r e c t i o n s w it h M ie r e d e l d e v e lo p e r l a a S i t e * d a y l i g h t - p r o c e s s i n g ta u t*

f i x e r P-*S was used*

A ft e r t h e f i l m had d r ie d , i t w as v ie w e d l a a n p e n c sr M ic r o film r e a d e r and th e d a ta p r e l e c t e d o n to a s h e e t o f g ra p h p a p er ana c a r e f u l l y tr a n s c r ib e d *

The v a lu e s o f

c a th o d e p o t e n t i a l v e r s u s tim e o f e l e c t r o l y s i s a r e t a b u la t e d i n A p p en d ices 1 th r o u g h ¥* X* The Chemioai© The s o l u t i o n s w ere made up from G*P* chem ical© and d i s t i l l e d w ater*

The p ro ce d u re u s e d was e s s e n t i a l l y on e

an e l e c t r o p l a t e r w> u ld u s e .

:

IV . T be ReauXtB M S t h e i r I n t e r o r © t a t l on T here i s no p r e c e d e n t f o r th e i n t e r p r e t a t i o n o f

th e t y p e o f in fo r m a tio n w h ich t h e s e e x p e r im e n ts h ave made a v a ila b le * In c o n s id e r in g i n t e r f a o i a l e l e c t r o eh em io a l phenen* en a w h ich o c c u r in tim e s o f th e o r d e r o f a fe w m illis e c o n d s ^ i t i s in f o r m a t iv e t o c o n s id e r how much o f t h e ex p o se d s u r f a c e c o u ld h ave b een a f f e c t e d *

A s im p le c a l c u l a t i o n

w i l l show t h a t 100 m illi& m p e res p e r sq u a re in c h f lo w in g f o r one m i l l i s e c o n d w i l l d e p o s it v e r y n e a r ly 2% o f a m o n olay er on t h e a p p a ren t s u r f a c e area*

However, i t i s

f a i r l y w e l l e s t a b l i s h e d t h a t 15 i s a good r o u g h n e ss f a c t o r f o r e l e c t r o d e p o s i t e d n i c k e l s u r fa c e s *

Hence th e p e r c e n t

6 ^Butler"!"' J A i L o p . ' c i t .' p.' 75 o f r e a l s u r f a c e a r e a c o v e r e d p er 100 m ,a , m s e e /s q ,in * i s more n e a r ly 0 * 1 $ , p r o v id e d o n ly t h a t t h e n ic k e l was d e p o s it e d a t random*

I t t h e r e f o r e seem s u n l i k e l y t h a t

t h e e f f e c t s w h ich w ere o b se r v e d i n t h e s e e x p e r im e n ts can b e e x p la in e d on th e b a s i s o f s u r f a c e a l t e r a t i o n , ‘‘ a c t iv e " m a t e r i a l , etc* The d a ta i n t h e a p p e n d ic e s show t h a t t h a t an " o v e r o v e r v o lta g e "

o f a p p r o x im a te ly 0*1 v o l t i s a v e r y common

o c c u r r e n c e f o r t h e " b ir th " o f a n i c k e l p l a t i n g p r o c e s s from th e s o l u t i o n s u se d h ere*

The c a th o d e p o t e n t i a l

r e a c h e s t h i s maximum p o t e n t i a l in tim e s o f t h e o rd er o f

JU *

§ m i l l ! Bee® j&te* JDf tii© data for v a r io u s e x p e r im e n ts a r e p l o t t e d on 1 aarg© s i z e { 1 8 1 f x 18 ’ V) c r o s s r u le d paper* th e c u r v e s a re rnrnm to. a p p r o x im a te r a t h e r c l o s e l y t h e v o lta g e* * tim e r e l a t i o n ­ s h ip f o r a s im p le r e s i s t a a c e - c a p a c i t a n c e (KC) e l e c t r i c a l

network w h ich i s "being e n e r g is e d by a sudden c o n s ta n t c u r r e n t p u ls e *

How i t i s w e l l e s t a b l i s h e d ( o f * r e fs * 1*

3 ,3 ,4 ) th a t m e ta l-s o lu tio n in te r f a c e s are e l e c t r i c a l l y e q u iv a le n t to a c a p a c it a n c e o f r e l a t i v e l y la r g e s is © ( o r d e r o f 100 m fd * /sq * cm *),

Hence we may draw an

e l e c t r i c a l l y e q u iv a le n t c i r c u i t f o r th e i n t e r f a c e a s fo llo w s 3 f i g u r e 3* m e ta l s u r f a c e

R

w here th e c a p a c ita n c e * 0* i s th e e l e c t r i c a l e q u iv a le n t o f th e in terf& ci& X c a p a c ita n c e a t any p a r t i c u l a r tim e ; r e s is t a n c e * H, i s

th e

th e e l e c t r i c a l e q u iv a le n t o f w h a tev er

e f f e c t s m a n if e s t th e m s e lv e s a s e l e c t r i c a l r e s i s t a n c e s i n th e i n t e r f a c e s

and t h e b a tte r y * B* i s th e a b s o lu t e

e l e c t r o d e p o t e n t i a l f o r th e g iv e n sy ste m .

When t h e s e

system © a r e m easured* t h e e x p lo r in g p ro b e a p p ea rs a t A* and th e p o t e n t i a l ch a n g es w h ich we o b s e r v e o ccu r b etw een

t h e m e ta l $ m £ %©« dhd,A#

New t h e e l e c t r i c a l p r o p e r t i e s

o f su ch a p a ^ a ll« X B0 c i r c u i t a r e w e l l u n d e r s to o d and a r e t r e a t e d i n any m odern e le m e n ta r y e l e c t r o n i c s t e x t ­ book (@»g. Gruft© S t a f f E l e c t r o n i c C i r c u i t s and Tubes p* 1 3 8 ,

M cG raw -H ill H.Y* 1 9 4 7 )*

One o f t h e m ost im p o r ta n t f e a t u r e s o f su ch an e l e c t r i c a l c i r c u i t i s i t© n tim e - constant** * constant** i s

eq u a l t o t h e p r o d u c t o f th e r e s i s t a n c e i n

ohms tim e s t h e c a p a c it a n c e i n fa r a d s * in seco n d s,

T h is ^tim e*

t h e tim e th e n b e in g

T h is t i m e , i s t h e i n t e r v a l r e q u ir e d to ch a rg e

th e c a p a c it o r to 6 3 . 2% o f i t s f i n a l v o lt a g e w h ich i s o f c o u r s e ap p ro a ch ed o n ly a s th e l i m i t o f an e x p o n e n t ia l. A f t e r 5 tim e c o n s t a n t s h a v e e la p se d * more than 9 9 $ o f th e ch an ge i n v o l t a g e h a s o ccu rred * i . e . tim e f u n c t io n i s

e s s e n t i a l l y on a p la t e a u .a n d m ore th a n

99% o f t h e c u r r e n t i s th e n f lo w in g th r o u g h p o r t io n

th e v o l t a g e -

o f th e c i r c u i t .

th© r e s i s t i v e

I f on© th e n p l o t s th© v a lu e s

t a b u la t e d i n th e a p p e n d ic e s and c o n s id e r s th e "peak*1 ( o r i n i t i a l p la t e a u ) v o l t a g e ch a n g es to b e a m a n if© s ta tio n o f t h e c h a r g in g o f an EG netw ork* th e f o llo w in g t ilin g s may b e c a l c u l a t e d : ,U> The tim e a t w h ich 6 3 .2 $ o f th e peak change o c c u r s may b e ta k e n from t h e g ra p h . T h is i s t h e '*tim e c o n s t a n t ’** ( 2 ) On t h e a ssu m p tio n t h a t th e e q u iv a le n t i a t e r f a c i a l r e s i s t a n c e and b a t t e r y ca n n o t h a v e changed ap pre­ c i a b l y ( s i n c e t h e r e i s no in fo r m a tio n c o n c e r n in g how th e y do ch an ge i n t h e s e s h o r t i n t e r v a l s ) th e v a lu e o f R may b e c a l c u l a t e d from th e peak v o lt a g e ch a n g e. R i s sim p ly th e p eak v o lt a g e change d iv id e d by th e c u r r e n t .

( 3 ) From th e v a lu e t h e tim e —con fit a n t and t h e v a lu e o f H th e eisse o f t h e c a p a c i t o r can h e ; oaldulibtdd* T h is in t e r & r b t a t f o h o f r e s u l t s d ep en ds upon how a c c u r a t e ly differed'©®® o f p o t e n t i a l can h e d eterm in ed d u r in g a s i n g l e e x p e r im e n t.

I t i s b e l i e v e d t h a t th e

d i f f e r e n c e s o f p o t e n t i a l i n any p a r t i c u l a r t a b l e i n t h e a p p e n d ix i s a c c u r a t e to a t l e a s t 3 m i l l i v o l t s ,

d iffe r e n c e s

l e s s th a n t h i s a r e n o t a c c u r a t e ly d e t e c t a b l e .

The

a b s o lu t e a c c u r a c y o f th e £ > c te n t ia ls r e p o r t e d i s p ro b a b ly n o t more th a n 9 b $ s i n c e t h i s i s a r e a s o n a b le v a lu e t© assum e f o r any o s c i l l o g r a p h i c m easu rem ent,

The r e a l v a lu e

o f t h e d a ta l i e s i n how a c c u r a t e ly t h e d i f f e r e n c e s i n p o t e n t i a l ca n b e d e t e c t e d s i n c e i t i s upon t h e s e d i f f e r e n c e s t h a t c a lc u la t io n © a r e b ased *

*

The a c c u r a c y o f t h e tim e i n t e r v a l s i s th e sw eep ©peed u s e d ,

d ep en dent upon

The ©peed© u s e d f o r r e c o r d in g m ost

o f th e d a ta p r e s e n t e d h e r e w ere su ch t h a t th e tim e s a re a c c u r a t e to 0 , 1 m illis e c o n d *

T h is w i l l r e s u l t i n c a p a c i­

t a n c e a c c u r a c ie s o f ab out «» 10 m id * , when c a l c u la t e d on th e b a s i s o f t im e - c o n s t a n t - r e s i s t a n c e m easurem ents*

The

a c c u r a c y o f t h e tim e d i f f e r e n c e s i s th e l i m i t i n g f a c t o r i n t h e e x p e r im e n ts r e p o r te d h e r e . C o n s id e r in g t h e d a ta i n th e a p p e n d ic e s from t h e p o in t o f v ie w o f BC t r a n s i e n t s in e q u iv a le n t RC e l e c t r i c a l network® th© f o l l o w i n g t a b u la t io n s may be mades

A- f o r

urn.

G o m m a iU o a

HiSO^SHgQ * X70 g / 1 * H3 BO3 *• 25 g / l . HiCia'SHgO * S® a / 1 , pH 2 ,8 c a th o d e a r e a 0 ,4 3 sq u a r e in c h E f f e c t o f C u rren t D e n s it y a t 25° C. ( S e e A ppendix I ) M i l l am peres p e r sq u a re In c h

C athode P o t e n t i a l a t one t im e c 021s t a n t

R e s is tiv e e q u iv a le n t i n ohms

C a p a e ita n c e e q u iv a le n t in mi cro P a ra d s

m

0 *6 9 0

7*3

180

100

0*792

5*3

235

150

0 .8 1 9

4* 1

350

200

0*820

3 .2

550

300

0*836

2*3

320

400

0*874

1 .7

370

E f f e c t o f T em perature on 100 m a /sq , in * B ir t h s ( S e e A ppendix IX) T em perature °C .

C athode P o t e n t i a l a t on e t im e c o n sta n t

4

0*797

6 .3

260

10

0*800

6*3

260

15

0 * 807

5*9

210

25

0*796

5*3

235

30

0 .7 9 9

4*8

160

39

0 .7 3 4

3 .7

170

43

0*695

2 ,9

230

50

0*641

2*5

270

R e s is tiv e e q u iv a le n t i n ohms

C a p a c ita n c e e q u iv a le n t i n m ic r o fa r a d s

S f i'e o t e f T r a e e r a tu r e on 3 0 0 m a /e q .in . B i rtlxe ^ ( S e e A pp en d ix I I I ) €«t*u»da P o t e n t i a l 1 t i d i tim e e o a e ta n t

te m p e r a tu r e °G.

B e s is tiv e e q u iv a le n t i n ohms

Oapaci ta n c e e q u iv a le n t i n m ic r o fa r a d s

5 {a© 11o v er * s h o o t 1*) 25

0 .8 1 3

2 ,0

960

0 .8 3 6

2 ,3

320

43

0*793

1*7

220

E f f e c t off T em perature on 200 m a /sq . i n . T em perature «c.

C athode P o t e n t i a l a t on e t im e c o n sta n t

R e s is tiv e e q u iv a le n t i n ohms

C a p a c ita n c e e q u iv a le n t i n m ic r o fa r a d s

5

0 ,8 4 6

3 ,5

285

25

0 .8 2 0

3 ,2

350

45

0 .7 7 3

2 ,5

190

55

0 .7 6 3

2 ,1

240

•&* B ffffeets off Chan&lnis C o n c e n tr a tio n off H a jo r S o lu t io n Comoonents 25 ° G

100 m a /sq , i n . 0 * 4 3 s q . I n , ca th o d e a r e a ( So© [email protected] IT)

HiB04*6H20 - 170 g / l , ITiC lg*6% 0 * 30 g / 1 ,

H3 BG5 * 25 g / l , pH - 3 ,8

C athode P o t e n t i a l a t one t im e - c o n s t a n t R e s i s t i v e e q u iv a le n t C a p a c ita n c e e q u iv a le n t B i S04*6H20 - 8 5 g/l. H iCl2*6H 20 * 1 5 g / l .

0 ,7 9 2 5 ,3 235

v o lts ohms mffd.

H3BO3 * 25 g/l. pH - 4 ,1

C athode p o t e n t i a l a t one t im e-con & tan t B e s t s t i v e e q u iv a le n t C a p a c ita n c e e q u iv a le n t

0 ,8 8 3 v o l t s 7 ,4 ohms 450 mffd*

*«

e q u iv a le n t >$20 H !C l2*$Ba 0

** B5 g/l,* ~ 1 3 ^/a.,

II&BO3 «* Bob® pH ** 6* 4

t xmm - co irn to u t

0 • 8 2a v o l t s a * «> *»*

c. a r e i n &&

H tS04*6% 0 - 170 & A 1 * I pB 3*3*

( S e e 'A p p ca^ x ' ^}* Oath©a© P o t e n t i d

,&n% co n sta n t

in

©qu i v a i e a t

qM

Jlefi©

0*792

5* 0

>-'4 «*& *£?**4#

0*1 & A

0*800

*1 t+ T1

170

0*33 a

0*703

**■. feu km : ■ft?

4* 2

260

0 .4 8 g / l . u r e th a n e

0*77?

5* 4

ISO

0 * 0 1 5 g/%# h n& phthol

0* 80 a

5*6

^dO

0*0? g /l*

0*736

5*6

0 .8 5 7

3*X

0 .7 2 5

4*7

2 nap& t& d

S |6 a l e u l i ou st© Ha 1*0 is /t# i s e l a t i n 3$ g / l .

u

«A

Jia t o r s m t e

o tso ^ * '

355

1^toffiW JE’itSar decrease® th e value of

■ ■ v-:"-^#3 , * in te r fa c to

w ith m t . r# i^ ll# " b t t h e * l a t e r f & e i & l © a p & citea c© # ^ u i v a l « i t t w t o m y e x t e n t co&tp&r&ble t o c h a n g e s i n

:'

- m m •iNifti

(a)

■

I n c r e a s i n g t « ^ « r a t w « d e c r e a s e ® t h e v a lu e of toe * r e e l s t i v e v q u i v a l e n t * * The “ c a p a c i t a n c e e q u i v a l e n t * se e sa s t© d e c r e a s e f r o s t 4 r t o 50® mad t h e n i n c r e a s e a g a i n t o §0®#

{5} For 2$ g / l * h o r ic a c id c o n c e n tr a tio n th e r e s i s t i v e and c a p a c i t i v e e q u iv a le n t® b o th I n c r e a s e w it h d e c r e a se d n ic k e l s a l t c o n c e n tr e t ie s # (4 )

The p r e s e n c e o f £5 g / l b o r i c a c i d i n a s t a n a a r d p l a t i n g c o n c e n t r a t i o n o i n i c k e l ®& t s r c o u c c ® t h e c a p a c ita n c e e q u i v a l e n t by a 1 a c t o r o f d. co m p ered t o t h e ammo c o n c e n t r a t i o n w i t h n o b o r i c a c id *

(5) The ad u ition agents which axe reported to be e x c e lle n t brlghtenere (of* Feab and Wittu«9 *Thc Influence of Organic Compound® in Hicnel P latin g S olu tion s1* Sletal. Industry {W,Y*} 50 3 0 6 , 5t5 § 429# 1 9 4 0 ) , 1 # eT m S ^ h y len e b lu e# th io u r e a and u r e th a n e g i v e a f a s t e r tim e c o n sta n t. th a n th© s o l u t i o n w it h no a d d it io n a g en t* In g e n e r a l t e e 4 c a p a c i t i v e e q u iv a le n t* i s a f f e c t e d a c r e by th e a d d it io n .agent® than th®. '•re* s i s t i v e e q u i v a le n t * 11 In c o n c lu s io n *

th e m e c h a n ism o f th e d e c a y

; f th e 54o v e r *

o v e r v o l t a g e 41 to th e s t e a d y © verveX tege i s n o t kn ow n .

A lth o u g h

th e A#C* o s c i l l o s c o p e w^® n o t s a t i s f a c t o r y f o r ouch lo n g in te r v a ls ,

i t i s e a t i m b e d from .a few e x p e r i m e n t s , t h a t th©

tim e r e q u i r e d t o g e t t o t u e s te a d y o v e r v o lt a g e v a lu e i s b e t w e e n 0*3| * 0 # 4 seco n d # . o v e r v o lta g e i s

\3 a e t h e r t h i s decay o f a peak

d u e t o a & p a e it a n a s c h a n g e s # r e s i s t i v e

b a t t e r y c h a n g e s o r c o m b in a tio n © o f a l l t h r e e i s is

c h a n g e s#

n o t known#

It

n o t known w h eth er t h i s phenomenon o f * o v er o v e r v o lta g e * 1® a

g e n e r a l one#

The e x p e r im e n ts d e s c r ib e d w ere p r im a r ily

vb ! e x p lo r a t o r y fffi D io tu r * , ^ “4^ 4

?*** .

1’r' ■' e le c t r ic a l c ir c u it

i® a d v a n ced o n ly ;a e a c o n v e n ie n t

p o ln V y ; d d j ^ t 4 y l^ ^ ® ® w^ o:ri * ° CenBidCJr v & rio y * ,SL8*iects Of

^ c f c t o d o iio la r iB a tio n .

.; ;'V"

';

m

m

m

i

V o lta g e -T im e R « la t io n a At 25° C E f f e c t o f O arront D e n s it y V o lt a g e s l i s t e d a r e c a th o d e p o t e n t i a l v e r s u s 0 . 1 N c a lo m e l h a lf^ o e lX * fim e i n t e r v a l i s 1 /6 0 0 se co n d and f r a c t i o n s o r m u ltip le ® t h e r e o f a f t e r th e © ta rt o f a c o n s t a n t c u r r e n t th ro u g h t h e e l e c t r o l y s i s c e l l . S o lu t io n i s a s ta n d a r d n i c k e l p l a t i n g s o l u t i o n whose c o m p o s itio n i s NiSG 4 *6 B2 0 - 170 g / l * M C l 2 # 6 H£ 0 - 30 g / l $ H3 BO3 - 2 5 g / l j pH * 3 . 8 . TABLE 1 50 Mi H i am peres P er Square In oh Time i n 1 /6 0 0 s e o «

C athode P o t e n t i a l

# Change Toward 30 s e o . P o te n tia l

0 .0

0 .4 5 9

0 .6

0 ,5 6 2

25#

1*0

0 .6 3 9

44#

2 .0

0 .7 1 4

62#

3 .0

0 .7 7 2

76#

4 .0

0 .7 9 6

82#

5. Q

0 .8 0 5

84#

6 .0

0 .8 1 7

87#

7 .0

0 .8 2 5

89#

8 .0

0 .8 2 5

89#

© .0

0 .8 2 5

89#

1 0 .0

0 .8 3 0

90#

S ta r t 30 se c o n d s P in a l change Maximum o v e r s h o o t

0 .4 5 9 0 .8 7 1 0 .4 1 2 Hone

0

100#

APPENDIX 1 d o n 't , TABLE f l pay S o n a re Inch. Time i n 1 /6 0 0 a e o .

C athode P o t e n t i a l

J Change Toward 30 P o te n tia l 0

0

0 .4 4 9

0*6

0 .7 2 6

59$

0*76

0*768

68$

1*75

0*952

10 4 $

2*75

0*977

114$

5 .7 5

0 ,9 8 6

116$

4*75

0 ,9 9 0

11 7 $

5*75

0*990

117$

6 ,7 5

0 ,9 9 0

117$

7 .7 5

0 .9 8 6

116 $

a , 75

0*986

1X6%

S t a r ti tcond© change turn o v e r s h o o t

0*459 0 ,9 1 4 0 .4 5 5 0 .0 7 7

AFFhHhlX I c o n H . TABES I I I

M £ S auare In ch l i a s i s 1 /6 0 0 e e o . - J a H a i s

Change Toward 30 s e c .

o.

0 . 433

0

0 .0 6

0*484

10#

0*13

0*549

23#

0 .2 5

0 *606

35#

0*30

0*626

39#

1*25

0*912

97#

2* 25

0*9 9 5

11 4 #

3*25

1*010

117#

4 , 25

1*014

118 #

5 ,2 5

1*014

11 8 #

>conds , ch an ge lum o v e r s h o o t

0*433 0 .9 2 6 0 * 493 0 .1 1 8

S ta r t

TABLE IV 300 M i111am peres p e r Square In ch Time In X /600 s e c .

Cathode P o t e n t i a l

T o w a r d 30

Po t e n t i a l 0 .1 3

1 .2 5

0 .4 1 0

0

0 . 530

31#

0 .6 0 8 0 ,7 0 3

QClrJ k'Z JQ/ 56#

0 .9 9 5 1.011

115#

3 . 25 3 .2 5

1 .0 4 7

122#

1 .0 5 9

124#

4 . 25

1 .0 5 9

134#

5 .2 5

1 .0 5 9

124#

6 .2 5 7 .2 5

1 .0 5 2

133#

1 .0 4 7

122#

S ta r t 30 se c o n d s F in a l change Maximum o v e r s h o o t

0 ,4 1 0 0 .9 3 2 0 .5 2 3 0 .1 2 5

sec.

APPEHDIX I C o n H , T A B l^ V

MO Mi H i am oereo P e r Square In ch Time jyg 1 /6 0 0 s e c . 0 .0

C athode P o t e n t i a l 0 * 394

J Change Toward 30 s e c . P o te n tia l 0

0 .0 4

0 ,4 6 9

1 3 .6 #

0 .2 0

0 ,6 5 5

47#

0 ,2 5

0 ,7 0 3

56#

0 ,4 0

0 ,8 2 6

78#

1 .0

1 .0 5 0

11 8 #

2 .0

1 ,0 7 0

122#

3 .0

1 .0 8 2

126#

4 .0

1 ,0 8 7

12 5 #

5 .0

1 .0 9 2

1 26#

S ta r t 30 second© P in a l change Maximum o v e r s h o o t

0 .3 9 4 0 .9 4 9 0 ,5 5 5 0 ,1 4 4

eon’ t . TABU VI

EM t o a t

In ch

Jg Change Toward 30 s e e , P o te n tx a l' O

0 .4 4 5

0

0 ,0 3

0 .5 4 3

17#

0 .0 7

0*589

25#

0 ,1 0

0 .6 4 1

0 .1 5

0 ,6 9 7

0.20

0 ,7 3 9

1*2

1*091

a, a

1,121

3 .2

1,121

117#

4 .2

1 .1 2 5

118#

5*2

1 .1 3 1

117#

S ta r t 30 s e c o n d s P in a l change Maximum o v e r s h o o t

0 , 44o

1 .0 2 2

0 ,5 7 7 0 .1 0 4

,r f

112#

APfSSPIX I...... X V o lta g e* T im e R e la t io n s a t 100 M l lia m p e r e s P er Square Inch B f f e c t o f T em perature V o lt a g e s l i s t e d a r e c a th o d e p o t e n t i a l v e r s u s 0 .1 R. c a lo m e l h a L # * a e li* tim e i n t e r v a l i s 1 /6 0 0 seco n d and f r a c t i o n s o r m u l t i p l e s t h e r e o f a f t e r t h e s t a r t ©f a c o n s t a n t c u r r e n t th ro u g h t h e e l e c t r o l y s i s c e l l . S o lu t io n i s a sta n d a r d n i c k e l p l a t i n g s o l u t i o n whose c o m p o s itio n i s U iS 0 4 * 6 H2 O * 170 g / l ; RiClo-OH^O «* 30 g / l j H3 BQ5 * 25 g /1 * pH * 3 . 8 . TABLE V I I

iSLfik 145S. AS VAQQ £ S £ .

C athode P o t e n t i a l

J> Change Toward 30

0 .0

0 .3 9 7

0

0*80

0 .7 6 0

67#

1 .0

0*795

73#

2 .0

0 .9 4 0

100#

3 .0

0 .9 6 8

109#

4 .0

0 .9 9 8

11 1 #

5*0

1 .0 1 7

114#

e .o

1 .0 2 7

116#

7 .0

1 .0 2 7

11 6 #

8 .0

1 .0 3 2

117#

9 .0

1 .0 3 2

117#

10 . 0

1*032

11 7 #

S ta r t 30 se c o n d s P in a l change Maximum o v e r s h o o t

0 .3 9 7 0 .9 4 0 0 .5 4 2 0 .0 9 2

t

Time in 1/600 eee^ ***. 0 .0

T ■""' 0 .3 9 7

!SsmBS SSSSSi 2° P otent* o t e n t iaa!l of

0 .7

0 .7 2 2

61$

1 .0

0 .7 8 5

73$

1 .7

0 .9 1 5

97$

2 .7

0*974

108$

3 .7

1 .0 0 3

114$

4 .7

1 .0 1 3

115$

5 .7

1 .0 1 7

116$

6 .7

1 .0 2 2

117$

1 .0 2 7

118$

1 0 .7

1 .0 2 7

118$

1 1 .7

1 .0 3 7

120$

{

S ta r t / 30 s e c o n d s P in a l ©hang© Maximum oy© reboot

0 .3 9 7 0 .9 3 0 0 .5 3 2 0 .1 0 5

s b m b u u

c o n * t,

TABES IX 1 8 8 _g T ia g i&

M 2*

0*0

C athode P o t e n t ! e.X j£ Change Toward 30 s e e . P o t e n t ia l 0*436 0

0*4

0*678

50#

0 ,0

0*726

60#

1*4

0 .9 2 1

100#

2*4

0*9 8 3

113#

3*4

1 .0 0 3

11 7 #

4*4

1*017

120#

5*4

1*022

12 1 #

S ta r t 30 se c o n d s P in a l change Maximum o v e r s h o o t

0*436 0 .9 2 1 0 .4 8 5 , 0*102 TABLK X 25° C

2 i M AM 1/&00 s e c #

C athode P o t e n t i a l

jf Change Toward 30 sec* P o te n t i a l

0*0

0 ,4 5 9

0

0 .6

0 .7 2 6

59#

0 .7 5

0 .7 6 6

68#

1 .7 5

0 ,9 3 2

104#

2*75

0 .9 7 7

114#

3*75

0 ,9 8 6

116#

4 ,7 5

0 .9 9 0

11 7 #

5 .7 5

0 ,9 9 6

117#

6 .7 3

0 .9 9 6

117#

7 .7 5

0 ,9 8 6

116#

8 ,7 5

0 .9 8 6

11 6 #

S ta r t- ■ ■: 30 se c o n d s P in a l change Maximum o v e r s h o o t

0 ,4 5 9 0 ,9 1 4 0*4 6 5 0 .0 7 7

APPBHPIX XI oon’t,

TABLE XI M i . Tim e i n 1 / 6 0 0

aeo.

C a th o d e P o t e n t i a l

jf Change Toward 30 a e o .

P o te n tia l

0

0 * 495

0*12

0*597

26#

0*25

0*659

4 2#

1*25

0*952

111%

2 * 25

0 .9 6 7

121%

3* 25

0 * 973

122%

4*25

0 .9 7 6

123%

5*25

0 .9 7 8

123%

S ta r t 30 se c o n d P in a l Change Maximum o v e r s h o o t

0*495

0

0*886

0*391 0*090 TABLE XII 39£ C*

Time i n .1/600. M S .

C athode P o t e n t i a l

% Change Toward 30 s e c .

0

0*498

0

0*2

0 .6 3 9

40#

0 .3 6

0 .7 3 1

66%

1 .2 5

0 .8 6 5

10 4/j

2*25

0 .8 7 0

106#

3 .2 5

0*870

10 6 #

4 .2 5

0 .8 7 0

106 #

5 .2 5

0 .8 7 0

106#

6 ,2 5

0 .8 7 0

10 6 %

S ta r t 30 se co n d P in a l change Maximum o v e r s h o o t

0 .4 9 8 ' 0*850 0*352 0*021

A P F M D I 3C X £ oon»t.

TABLE X III 430 2 i s s i s iZ iSP . m &*

C athode P o t e n t i a l

% Change Toward 30 s e c . P o te n tia l 0%

0.

0* 5X0

0 .1

0 .5 5 0

14#

0 .2

0 .6 0 7

33#

1 .2

0 ,8 0 3

100#

2 ,2

0 .8 0 3 ,

100#

3 .2

0 .3 0 3

100#

4 .2

0 .8 0 3 ,

100#

S ta r t 30 se c o n d F in a l change Maximum o v e r s h o o t

0 .5 1 0 0 .8 0 3 , 0 ,2 9 4 hone -

APmMDIX I I c o n 't TABUS XIV 50° £ , C athode P o t e n t i a l

©

0 ,4 9 5

Q,*2

0 .5 9 7

36#

Q.v3

0 ,6 2 3

45#

0, 4

0**649

55#

1 ,3

0 .6 9 4

7 3#

2 ,3

0 .7 1 1

76#

3„3

0 ,7 1 5

4 ,3

0 .7 2 1

80 %

5 ,3

0 .7 2 6

82#

6 ,3

0 .7 2 6

82#

7 .3

0 ,7 2 6

00

# Change Toward P o te n tia l

30%

iX

0 ,9 4 1

123%

2*X

0*961

130$

3 ,1

0 ,9 5 7

132$

4 ,1 ,

0 ,9 5 7

£32$

S ta r t 30 sa c o u d P in a l change Maxi mum ov e r slxo o t

0 ,4 5 6 0^835 0 ,3 7 9 0 .1 2 2

TABLE XXI M illiaffip m eB p er 3 auare Inqh S S i S* * 20 C Time i n 1 /6 0 0 sec*

Cathode P o t e n t i a l

% Change I J e m d P o te n tia l Id -•

*>

0 1 491

o .o a

0 ,5 9 2

31$

0*16

0 ,6 6 8

54$

0 .2 5

0 .7 1 9

69/*

" 0 ,3 3

0*759

Q'2%

0 .8 9 5

123$

2 .0

0 .9 1 6 *

12 9 $

3 .0

0 .9 2 1

131$

4 ,0

0 ,9 2 1 *

131$

1 ,0

■■

S ta r t 30 se co n d P in a l change Maximum o v e r s h o o t

0 .4 9 1 0 .8 2 0 0 .3 2 9 0 ,1 0 2

V e lt a g e s . l i s t e d , a rg ca th o d e p g t e n t ia j t T a r s u s 0 ,1 IT C a lo m e l h a l f * c e l l . Tim© i n t e r v a l i s 1 /6 0 0 se co n d and f r a c t i o n s or m u lt ip le s t lie r e o f a f t e r th e s t a r t i& t .ijt0 ©: liiliX li a m p ere c o n s t a n t c u r r e n t .th r o u g h t h e /

e le c tr o ly s is c e ll,

: S

.

^

TABLE XXII S tan d ard Hi o&el S o lu t io n H S o 4 *6% 0 * 170 g / l W ai2 * 6 H 20 * 30 g /1 Time i n 1 /6 0 0 s e c .

P

H3 B0s • 25 i / 1 pH - 3 .8

Cathode P o t e n t i a l

J[

Change Toward 50 s e c ,

P o te n ti a l

0

0 , 430

0

0 .6

0 ,7 2 6

59 %

0 .7 5

&&%

X# 7 5

0 .7 6 8 _■ f 'f 0 .9 3 2

2*75

0*977

114;?

3*75

0 .9 8 6

116$

4 .7 5

0 ,9 9 0

117$

5 ,7 5

0 .9 9 0

117$

6 ,7 5

0 . 900

117,?

7 .7 5

0 .9 8 6

116$

■-a*?*-.-

a , 986

116$

Cond change urn o v e r s h o o t

0 .4 5 9 0.9X 4 0 .4 5 5 0 .0 7 7

S ta r t

104/i

TABLE XXXII S o lu t la n D ila t e d w it h B o r ie A old S o lu t io n H iSo 4 *6 H^Q • § 8 g / l , S/ 1 *

25 g / l *

Hi d2