Polymeric Materials for Corrosion Control - American Chemical Society

18 Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on May 3, 2016 | http://pubs.acs.org Publication Date: October 14, 1986 | doi: 10.1021/bk-1986-0322.ch018

New Polymeric Materials for Metal Conversion Coating Applications A. Lindert and J. I. Maurer Parker Chemical Company, 32100 Stephenson Highway, Madison Heights, MI 48071

In order to obtain maximum corrosion protection for painted metal articles, the metal parts are pretreated with an inorganic conversion coating prior to the painting operation. These zinc or iron phosphate coatings greatly increase both paint adhesion and corrosion protection. T r a d i t i o n a l l y , a chromic acid post-treatment has been applied to these phosphatized metal surfaces to further enhance corrosion protection. Due to environmental concerns, research efforts have been directed toward the replacement of chromate-based post-treatments. This paper focuses on a new unique chromium free post-treatment based on "Mannich d e r i v a t i v e s " of po1y-νiny1phenol which have demonstrated excellent performance on both zinc and iron phosphate treatments. A l a r g e s e g m e n t o f t h e m e t a l p a r t s p r o d u c e d by i n d u s t r y a r e p a i n t e d f o r b o t h d e c o r a t i v e p u r p o s e s a s w e l l as t o i n c r e a s e t h e c o r r o s i o n r e s i s t a n c e and e x t e n d t h e u s e f u l l i f e o f the product. To o b t a i n maximum q u a l i t y f r o m p a i n t e d m e t a l a r t i c l e s , i t i s o f p a r a m o u n t importance t o p r e t r e a t t h e m e t a l p a r t s w i t h a c o n v e r s i o n c o a t i n g procès s . ( 1, 2 ) P r e t r e a t m e n t p r o c e s s e s c o n t r i b u t e a s i g n i f i c a n t improvement i n c o r r o s i o n p r o t e c t i o n and d u r a b i l i t y t o m e t a l a r t i c l e s by: 1. 2. 3. 4.

I n c r e a s i n g b l i s t e r r e s i s t a n c e i n humid environment Promoting p a i n t a d h e s i o n D e c r e a s i n g t h e spread o f c o r r o s i o n o f t h e m e t a l substrate Reducing m e t a l - p a i n t i n t e r a c t i o n s .

A conversion c o a t i n g p r o v i d e s an i n s u l a t i n g , o f t e n n o n - c o n d u c t i n g c o a t i n g which b o t h i n h i b i t s c o r r o s i o n once p a i n t e d and p r o v i d e s a b e t t e r s u r f a c e f o r p a i n t a d h e s i o n . 0097-6156/86/0322-0203$06.00/0 © 1986 American Chemical Society

Dickie and Floyd; Polymeric Materials for Corrosion Control ACS Symposium Series; American Chemical Society: Washington, DC, 1986.

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POLYMERIC MATERIALS FOR CORROSION CONTROL

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T h e r e a r e e s s e n t i a l l y t h r e e main s t e p s i n a c o n v e r s i o n coating process; c l e a n i n g , c o n v e r s i o n c o a t i n g , and p o s t - t r e a t i n g . These t h r e e d i f f e r e n t , but e q u a l l y important, steps i n the p r e t r e a t m e n t o f m e t a l a r t i c l e s w i l l be d i s c u s s e d i n more d e t a i l f o r t h e p u r p o s e o f p r o v i d i n g a background f o r t h e main emphasis o f t h i s paper, the post-treatment part o f the c o n v e r s i o n c o a t i n g process, and more s p e c i f i c a l l y chromium-free polymeric p o s t - t r e a t m e n t s which have been d e v e l o p e d i n r e c e n t y e a r s t o r e p l a c e t h e e n v i r o n m e n t a l l y u n a c c e p t a b l e chromate systems.

Background - P r e s e n t

Industrial

Practice

D e p e n d i n g u p o n t h e q u a l i t y l e v e l d e s i r e d , the type o f p a i n t and the a p p l i c a t i o n method used, and t h e m e t a l m i x t r e a t e d , a number o f d i f f e r e n t t y p e s o f p r e t r e a t m e n t processes are a v a i l a b l e . For use as a p a i n t b a s e , t h e p h o s p h a t e p r o c e s s e s a r e e i t h e r o f t h e " i r o n phosphate" o r t h e " z i n c phosphate" t y p e . The p r e t r e a t m e n t can be as s i m p l e as a t h r e e - s t e p p r o c e s s , i n which t h e c l e a n i n g and c o n v e r s i o n c o a t i n g s a r e c o m b i n e d i n t h e same s t e p as f o l l o w s : THREE STAGE PROCESS 1. 2. 3.

Clean/Conversion Water R i n s e Post-Treatment

Coating

The a b o v e t y p e o f p r o c e s s i s most o f t e n used i n t h e a p p l i c a t i o n o f an i r o n p h o s p h a t e - i r o n o x i d e c o n v e r s i o n c o a t i n g . These amorphous c o a t i n g s a r e g e n e r a l l y d e p o s i t e d a t a c o a t i n g weight o f f r o m 20 t o 80 m g . / s q . f t . A l t h o u g h t h e s e iron phosphate c o a t i n g s improve p a i n t a d h e s i o n , a post-treatment i s r e q u i r e d t o o b t a i n a c c e p t a b l e c o r r o s i o n p r o t e c t i o n , and i m p r o v e s t h e c o r r o s i o n p r o p e r t i e s o f t h e c o n v e r s i o n c o a t i n g by an o r d e r o f magnitude. On t h e o t h e r e n d encompass many s t e p s :

o f the spectrum,

the pretreatment

can

EIGHT STAGE PROCESS 1. 2. 3. 4. 5. 6. 7. 8.

Clean Water R i n s e Clean Water R i n s e ( C o n d i t i o n i n g Agent) Conversion Coating Water R i n s e Post-Treatment D e i o n i z e d Water R i n s e

T h i s more i n v o l v e d m u l t i - s t e p p r o c e s s c a n be used f o r b o t h i r o n phosphate and z i n c p h o s p h a t e c o n v e r s i o n c o a t i n g p r o c e s s e s .



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Metal Conversion Coating Applications

205

I n g e n e r a l , t h e z i n c p h o s p h a t e p r o c e s s r e q u i r e s t h e above m u l t i - s t e p procedure s i n c e , w i t h these c o a t i n g s , i t i s o f t e n n e c e s s a r y t o employ a s u r f a c e a c t i v a t i n g agent c o n t a i n i n g t i t a n i u m phosphate. The t i t a n i u m phosphate c a n be f o r m u l a t e d e i t h e r i n t o t h e c l e a n e r o r used i n the w a t e r r i n s e p r e c e d i n g the z i n c phosphate c o a t i n g s o l u t i o n . The z i n c p h o s p h a t e t r e a t m e n t b a t h s can d e p o s i t e i t h e r c r y s t a l l i n e z i n c phosphate ( h o p e i t e ) or z i n c - i r o n phosphate ( p h o s p h o p h y l i t e ) c o a t i n g s at a p p r o x i m a t e l y 130 t o 250 mg./sq. f t . By t h e m s e l v e s , these c o a t i n g s can improve p a i n t a d h e s i o n and g i v e c o r r o s i o n p r o t e c t i o n t o m e t a l a r t i c l e s . A p p l i c a t i o n of a p o s t - t r e a t m e n t can f u r t h e r improve c o r r o s i o n p r o t e c t i o n by an o r d e r o f 1 t o 2 t i m e s d e p e n d i n g on t h e t y p e o f p a i n t used.

Chromium

Post-Treatments

The o r i g i n a l p o s t - t r e a t m e n t s c o n s i s t e d o f 0 . 0 2 - 0 . 1 % o p e r a t i n g s o l u t i o n s o f chromic a c i d i n w a t e r . V a r i a t i o n s and i m p r o v e m e n t s h a v e b e e n made i n c h r o m a t e p o s t - t r e a t m e n t s t o overcome a l k a l i n e water c o n d i t i o n s , d e s i g n t r e a t m e n t s s p e c i f i c f o r z i n c p h o s p h a t e c o a t i n g s (3_) , and t o d e v e l o p r e a c t i v e t r i v a l e n t - h e x a v a l e n t chromium chromate complex t r e a t m e n t s w h i c h c o u l d be r i n s e d w i t h w a t e r w i t h o u t d e c r e a s i n g t h e c o r r o s i o n r e s i s t a n c e . (4) A f u r t h e r development i n chromium p o s t - t r e a t m e n t t e c h n o l o g y was t h e use o f t r i v a l e n t c h r o m i u m compounds . (_5) These post t r e a t m e n t s are l e s s t o x i c and e l i m i n a t e the r e d u c t i o n s t e p e m p l o y e d f o r w a s t e w a t e r treatment i n chromate e f f l u e n t s . However, t r i v a l e n t chromium b a s e d p o s t t r e a t m e n t s a r e l e s s f o r g i v i n g and more c a r e must be e x e r c i s e d i n c o n t r o l l i n g p r o c e s s v a r i a b l e s i n order to maintain quality. In a d d i t i o n , chromium e f f l u e n t i s a l w a y s a p o s s i b i l i t y i f inadequate c o n t r o l o f the d i s p o s a l o c c u r s .

Chrome-Free

Post-Treatments

The n a t u r a l l y o c c u r r i n g t a n n i n s w e r e t h e f i r s t p o l y p h e n o l i c o l i g o m e r s and p o l y m e r s e m p l o y e d a s ρο s t - t r e a t m e η t s o n phosphatized metal surfaces. T a n n i n p o s t - 1 r e a t m e n t s gave r e a s o n a b l y good r e s u l t s o v e r z i n c p h o s p h a t e c o n v e r s i o n c o a t i n g s where t h e p o s t - t r e a t m e n t , can i n c r e a s e the c o r r o s i o n r e s i s t a n c e by 1 to 2 f o l d . ^ 6 ) F o r m u l a t i o n s of tannins/melamine-formaldehyde r e s i n s f u r t h e r i m p r o v e d t h e a b o v e s y s t e m and were shown t o i n c r e a s e the c o r r o s i o n r e s i s t a n c e o f i r o n p h o s p h a t e c o a t i n g s ( 7 ) w h e r e t h e use o f a p o s t - t r e a t m e n t i s c r i t i c a l f o r good c o r r o s i o n r e s i s t a n c e . These tannin/melamine-formaldehyde f o r m u l a t i o n s gave t h e b e s t r e s u l t s w i t h o u t the use o f a water r i n s e and r e q u i r e d an oven cure s t e p . The d e v e l o p m e n t o f new p a i n t t e c h n o l o g y has mandated f u r t h e r improvements i n the performance o f non-chrome r i n s e s . G r e a t e r use o f a f i n a l w a t e r r i n s e i n t r e a t m e n t a p p l i c a t i o n s has t a k e n p l a c e p a r t i c u l a r l y w i t h t h e a d v e n t o f a n o d i c and c a t h o d i c e l e c t r o p a i n t i n g w h i c h r e q u i r e t h e use o f a d e i o n i z e d r i n s e t o prevent paint contamination. H i g h s o l i d s p a i n t s w h i c h t e n d t o be more


206



s e n s i t i v e t o s u r f a c e r e s i d u e s and i r r e g u l a r i t i e s a l s o b e n e f i t from a f i n a l water r i n s e s i n c e t h i s e x t r a s t e p r e d u c e s surface impurities. T h e s e more r e c e n t d e v e l o p m e n t s i n t h e c o n v e r s i o n c o a t i n g p r o c e s s , r e q u i r e t h a t the p o s t - t r e a t m e n t be r e a c t i v e w i t h the m e t a l s u r f a c e and not wash o f f i n the water r i n s e s t e p . I n t h e development o f a r e a c t i v e non-chrome p o s t - t r e a t m e n t , a v a r i e t y o f p h e n o l i c r e s i n s were s y n t h e s i z e d and commercial p h e n o l i c r e s i n s e v a l u a t e d . I t was found t h a t p h e n o l - f o r m a l d e h y d e r e s i n s , creso 1-formaldehyde c o n d e n s a t e s , ο r t h ο - η ο ν ο 1 ak r e s i n s , and p h e n o l - f o r m a l d e h y d e e m u l s i o n s gave p o s i t i v e r e s u l t s when e m p l o y e d as p o s t - t r e a t m e n t s o v e r z i n c and i r o n p h o s p h a t e conversion coatings. The a b o v e m a t e r i a l s a l l p o s s e s s e d drawbacks. The m a t e r i a l s i n g e n e r a l have poor w a t e r s o l u b i l i t y a t low c o n c e n t r a t i o n s used i n p o s t - t r e a t m e n t a p p l i c a t i o n s and had t o be d r i e d and baked i n p l a c e i n o r d e r t o o b t a i n good p e r f o r m a n c e . T h e b e s t r e s u l t s w e r e o b t a i n e d w i t h p o l y - 4 - v i n y l p h e n o l and d e r i v a t i v e s t h e r e o f as shown i n the f o l l o w i n g s t r u c t u r e :(8,9,10)

X = H X = CH 0H 2

X = CH N(CH3)CH2CH OH 2

2

η Structure 1

P o l y - 4 - v i n y l p h e n o l (X=H) was e v a l u a t e d from e t h a n o l due t o poor s o l u b i l i t y and s t a b i l i t y i n a l k a l i n e s o l u t i o n s . Poly-4v i n y l p h e n o l - f o r m a l d e h y d e condensate (X=CH20H) was a p p l i e d from an a l k a l i n e s o l u t i o n and was s o l u b l e and s t a b l e a t a pH o f 9.5 o r greater. The p o l y - 2 - [ m e t h y l ( 2 - h y d r o x y e t h y 1 ) a m i n o J m e t h y l 4 - v i n y l p h e n o l [X=CH2N(CH3)CH2CH20H] d e r i v a t i v e s y n t h e s i z e d by t h e " M a n n i c h " c o n d e n s a t i o n o f 2 - ( m e t h y l a m i n o ) e t h a n o l , formaldehyde and t h e p o l y - 4 - v i n y l p h e n o l was a p p l i e d t o t h e t r e a t e d m e t a l a t an a c i d i c pH as d e s c r i b e d below and was s o l u b l e i n water over a wide pH r a n g e ( b e l o w 1 t o 7 . 8 ) . Both the p o l y - 4 - v i n y l p h e n o 1 f o r m a l d e h y d e c o n d e n s a t e and t h e " M a n n i c h " d e r i v a t i v e have d e m o n s t r a t e d e x c e l l e n t p e r f o r m a n c e as p o s t - t r e a t m e n t s over b o t h z i n c and i r o n p h o s p h a t e c o n v e r s i o n c o a t i n g s . However, i n a t y p i c a l i n d u s t r i a l t r e a t m e n t i n s t a l l a t i o n , there i s considerable a c i d " d r a g - i n " f r o m t h e p h o s p h a t i ζ i n g and s u b s e q u e n t rinsing stages. T h i s a c i d " d r a g - i n " w i l l p r e c i p i t a t e and c o n t a m i n a t e the a l k a l i n e soluble poly-4-vinylphenol-formadlehyde condensate. The " M a n n i c h " a d d u c t , b e i n g a c i d s o l u b l e , i s n o t a f f e c t e d by a c i d


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d r a g - i n f r o m t h e p r i o r t r e a t m e n t s t a g e s and h a s f o u n d g r e a t e r acceptance. C o m m e r c i a l p r o d u c t s h a v e been developed employing the p o l y - 4 - v i n y l p h e n o l d e r i v a t i v e s and a r e p r e s e n t l y used i n b r o a d spectrum o f i n d u s t r i a l i n s t a l l a t i o n s i n c l u d i n g the f u r n i t u r e , a p p l i a n c e , and automotive markets.


P o l y v i n y l p h e n o l Post-Treatments The q u a l i t y observed w i t h "Mannich" d e r i v a t i v e s o f p o l y v i n y l p h e n o l i s a f f e c t e d by t h e c o n c e n t r a t i o n , time o f t r e a t m e n t , t e m p e r a t u r e , pH, and whether o r not a f i n a l d e i o n i z e d water r i n s e i s used. The r e s u l t s shown i n T a b l e s I - I I I b e l o w r e p r e s e n t e v a l u a t i o n s c o n d u c t e d f o r po l y - [ m e t h y l ( 2 - h y d r o x y e t h y 1 ) a m i n o ] m e t h y l - 4 v i n y l p h e n o l , as shown i n S t r u c t u r e I . P o s t - t r e a t m e n t s b a s e d on p o l y v i n y l p h e n o l s overcome d e f i c i e n c i e s o b s e r v e d w i t h p r e v i o u s chrome-free r i n s e s , s i n c e these s y s t e m s a r e r e a c t i v e and a f i n a l w a t e r r i n s e a c t u a l l y i m p r o v e s p e r f o r m a n c e as i s i l l u s t r a t e d i n T a b l e I where t h e new non-chrome system i s e v a l u a t e d on B o n d e r i t e 1 0 0 0 , a n i r o n p h o s p h a t e c o n v e r s i o n c o a t i n g , as a f u n c t i o n o f c o n c e n t r a t i o n w i t h and w i t h o u t a f i n a l w a t e r r i n s e . I t i s also

TABLE I POLYVINYLPHENOL POST-TREATMENT IRON PHOSPHATE BATH CONCENTRATION VS. FINAL WATER RINSE#

POST-TREATMENT CONCENTRATION (% SOLIDS) .01

WATER RINSE NO

.05

.25

0-2S 0-i2S

X X X

.10 .25

5-5 X

.05 .10

YES

X

.01

SALT SPRAY 504 H0URS##

0-1 2-3 0-lS

X X

4-6 X

0-lS

CHROMIC CHROMATE*

X

0-lS

NO POST-TREATMENT

X

7-9

# DURACRON 200 WHITE ENAMEL, PPG INDUSTRIES, INC. ## ASTM - B-117 RATING-PAINT CREEPBACK FROM SCRIBE IN 1/16TH INCH. * FOR CHROMIC CHROMATE POST-TREATMENTS SEE REFERENCE 3



208

TABLE I I POLYVINYLPHENOL POST-TREATMENT IRON PHOSPHATE## TEMPERATURE - PH (TREATMENT TIME - 30 SECONDS) BATH TEMPERATURE 100

BATH PH


120

140

0-1

4.6 0-lS

6.5

120 140

0-i2S

6.5

100

SALT SPRAY##

0-1

4.6 0-l

6.5

s

2-2

4.6

# DURACRON 200 WHITE ENAMEL, PPG INDUSTRIES, INC. ## ASTM - B-117 RATING-PAINT CREEPBACK FROM SCRIBE IN 1/16TH INCH. * FOR CHROMIC CHROMATE POST-TREATMENTS SEE REFERENCE 3

TABLE I I I POLYVINYLPHENOL POST-TREATMENT ZINC PHOSPHATE AUTOMOTIVE BODY PAINT SCAB OR CYCLE TEST

COLD ROLLED STEEL

RATING

AVERAGE

CREEPAGE**

CHROME FREE SYSTEM

8/7

1.5 mm

CHROMIC CHROMATE*

8/6

2.0 mm

WATER ONLY

2/2

9.0

GALVANIZED STEEL

RATING

AVERAGE

mm

CREEPAGE

CHROME FREE SYSTEM

9/8

0.8 mm

CHROMIC CHROMATE*

9/6

1.6 mm

WATER ONLY

5/4

5.0 mm

* FOR CHROMIC CHROMATE POST-TREATMENT - SEE REFERENCE 3. ** PAINT CREEPBACK FROM A SCRIBE IN MILLIMETER. a p p a r e n t t h a t t h e c o n c e n t r a t i o n i s n o t c r i t i c a l as e x c e l l e n t r e s u l t s a r e o b t a i n e d f r o m 0.05% t o 0.25% s o l i d s i n a w o r k i n g solution. F o r optimum c o s t / p e r f o r m a n c e the post-treatments are o p e r a t e d a t 0.1% s o l i d s when a f i n a l w a t e r r i n s e i s u s e d and a t 0.05% i n t h o s e i n s t a l l a t i o n s w h e r e a f i n a l w a t e r r i n s e i s n o t available.


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T a b l e I I i l l u s t r a t e s t h e i n t e r r e l a t i o n between temperature and pH o f the p o l y v i n y l p h e n o l treatment s o l u t i o n . These s o l u t i o n s c a n be a d e q u a t e l y o p e r a t e d o v e r a w i d e r a n g e o f pH, b u t t h e temperature o f the s o l u t i o n i s an i m p o r t a n t p a r a m e t e r and s h o u l d be m a i n t a i n e d above 100°F f o r o p t i m u m r e s u l t s . I n most c a s e s , treatment times o f 15 t o 30 seconds are adequate. The " M a n n i c h " a d d u c t s y n t h e s i z e d f r o m t h e c o n d e n s a t i o n o f formaldehyde, 2 - ( m e t h y l a m i n o ) e t h a n o l and p o l y - 4 - v i n y l p h e n o l as s h o w n i n S t r u c t u r e I , h a s b e e n e v a l u a t e d as a f u n c t i o n o f m o l e c u l a r weight v e r s u s c o r r o s i o n r e s i s t a n c e as m e a s u r e d by s a l t s p r a y and h u m i d i t y t e s t s on B o n d e r i t e 1000, an i r o n p h o s p h a t e c o n v e r s i o n c o a t i n g . The m o l e c u l a r w e i g h t o f t h e p o l y m e r was v a r i e d from a p p r o x i m a t e l y M = 2,900 t o 60,000. The c o r r o s i o n r e s i s t a n c e r e s u l t s were e s s e n t i a l l y e q u i v a l e n t o v e r t h e m o l e c u l a r weight range e v a l u a t e d . w

I n g e n e r a l , p a i n t a d h e s i o n and s a l t s p r a y c o r r o s i o n i n h i b i t i o n o f i r o n phosphate c o a t i n g s p o s t - t r e a t e d w i t h p o l y v i n y l p h e n o l d e r i v a t i v e s have been e q u a l t o or s u p e r i o r t o t h a t o b t a i n e d w i t h chromate based systems. T h i s has been t h e c a s e p a r t i c u l a r l y w i t h many h i g h s o l i d s p a i n t s . On z i n c p h o s p h a t e c o n v e r s i o n c o a t i n g s , t h e " M a n n i c h " d e r i v a t i v e s of p o l y - 4 - v i n y l p h e n o 1 have demonstrated performance e q u i v a l e n t to chromic chromate systems i n s a l t spray, humidity, and p h y s i c a l t e s t i n g . I n a d d i t i o n , Table I I I i l l u s t r a t e s r e s u l t s o b s e r v e d w i t h a u t o m o t i v e body p a i n t s y s t e m s e v a l u a t e d by t h e "scab" o r " c y c l e " t e s t which causes f a i l u r e more t y p i c a l o f a c t u a l end use c o n d i t i o n s than do s a l t spray e v a l u a t i o n s . A g a i n , r e s u l t s e q u i v a l e n t t o chromic-chromate p o s t - t r e a t m e n t s were o b t a i n e d . In a d d i t i o n , t h e h u m i d i t y r e s i s t a n c e and a d h e s i o n t e s t s were e s s e n t i a l l y e q u i v a l e n t t o the chromium c o n t r o l s . S u r f a c e A n a l y s i s o f P o l y v i n y l p h e n o l Post-Treatments A P h y s i c a l E l e c t r o n i c s M o d e l 565 Scanning Auger Spectrometer was e m p l o y e d f o r a n a l y s i s o f t h e p o l y v i n y l p h e n o l b a s e d r i n s e s on B o n d e r i t e 1000 i r o n p h o s p h a t e c o n v e r s i o n c o a t i n g s . A n a l y s i s and depth p r o f i l i n g o f the c o n v e r s i o n c o a t i n g showed the c o a t i n g t o be o f a g r a n u l a r a p p e a r a n c e and composed o f an i r o n p h o s p h a t e - i r o n o x i d e c o a t i n g o f a p p r o x i m a t e l y 2000A t h i c k n e s s . A 100A l a y e r o f an o r g a n i c m a t e r i a l covered the phosphate c o a t i n g and was assumed t o c o n t a i n t h e p o l y v i n y l p h e n o l b a s e d po s t -1 r e a t m e n t . This c o n c l u s i o n was f u r t h e r c o n f i r m e d by XPS a n a l y s i s u s i n g a Model 560 Auger/ESCA s p e c t r o m e t e r i n w h i c h t h e n i t r o g e n p r e s e n t i n t h e p o s t - t r e a t m e n t was o b s e r v e d i n the top 100A l a y e r c o n t a i n i n g the organic m a t e r i a l . Acknowledgment The A u g e r and XPS a n a l y s i s and i n t e r p r e t a t i o n o f t h e p o s t treatment on i r o n p h o s p h a t e s u r f a c e s was c o n d u c t e d by Dr. J . A. K r a m e r o f P a r k e r C h e m i c a l Company. Auger a n a l y s i s was performed


210


at t h e CRISS C e n t e r , Montana S t a t e U n i v e r s i t y by NSF g r a n t CHE 7916134.

which

i s supported

Literature Cited


1.

J . I. Maurer, "Preparation of Metal Surfaces for Organic Finishes", American Society of Tool and Manufacturing Engineers, Technical Paper, FC-68-652 2. "Metal Handbook", Volume 5, 9th E d i t i o n , pp. 434-456, American Society for Metals 3. W. R. Cavanagh, U.S. Patent 2,970,935 4. J . I. Maurer, R. E. Palmer, V. D. Shah, U.S. Patent 3,279,958 5. J . I. Maurer, R. Ε. Palmer, V. D. Shah, U.S. Patent 3,222,226 6. L. Kulick, Κ. I. Saad, U.S. Patent 3,975,214 7. L. Kulick, J . K. Howell, Jr., U.S. Patent 4,039,353 8. A. Lindert, U.S. Patent 4,376,000 9. A. Lindert, U.S. Patent 4,433,015 10. A. Lindert, J . Kramer, U.S. Patent 4,457,790 RECEIVED March 14, 1986


Polymeric Materials for Corrosion Control - American Chemical Society

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