ANJUMAN COLLEGE OF ENGINEERING AND TECHNOLOGY DEPARTMENT OF

ANJUMAN COLLEGE OF ENGINEERING AND TECHNOLOGY � DEPARTMENT OF CHEMISTRY SEMESTER-II � ENGINEERING CHEMISTRY � CORROSION SCIENCE �Presented By- Prof. Shahabaz Khan

INTRODUCTION � “The destruction of a material through an unwanted chemical or electrochemical reaction that occurs between the environment and the surface of material”. � The definition of corrosion includes both metallic and nonmetallic material, but the term corrosion is invariably used to denote the destruction of metal.

METALLIC CORROSION

CORROSION : REVERSE OF METALLURGY n i d e t r e v n o c s i l s a t s e e c m o r e p h t e , s n r o e i v s e o r r r e n o i k c i g l i g r s i n o i t r I s t. i s Du d m n o u r f o l p a t s m e u o c o m i s r e t i a h t v to f f o o n m o r i t o c f a e r t h t x n i t of e n e s e r. p s s d i n h u c i o wh comp

TYPES OF CORROSION �Pitting Corrosion �Inter Granular Corrosion �Stress Corrosion �Water line Corrosion

PITTING CORROSION ll e c n o i t a r t en c n o c o t e e du h s t i t d I n. a n e o i c s a rro urf o s c c i l m l r a t o f e i n m e -u h n t o n n i s y i t i s e i n h T ge o r e t e h r o t or i p a e action nvironment. r e h w e , s t m r a s a e p e h g d t e n t i r a ve n o o cord c i s e o h r t o a c s of rt a e t t s is a r h n t r o i e e s r h o o g r f i r e h o r c e a Th nd. The a n o d i e t a m r m o r f cavity is use a pit or hole fo corrosion. portion ca is known as pitting corrosion y r e v s i n o i ros r o , c e f d o o e h t t a a r c s e th ta c m a r h o f c i s i h y w t al, avi t c e r m o f t o i p e c a. a e f r d u o s n Once a e h n t a se th u n a e c e g y b x d o i f p ra so s e c c a r e t a has a gre

th i w d e r e v o c e r a ich h r w o , t s r i e c d , a f s t r i u s s o c p i l e l d a t e e l. a y c l i s , a l t i c d u � The m a d e o r r p d e n d o i e o s r d r o o n c a e r e a corro a m , r o c e t b a l m a t r any othe red portion of me thode. e Such cov vered become ca o c n u e l i wh

INTER GRANULAR CORROSION

ULAR N A R G R E T N I E TO L B I T P E C HE T S U S S W E O R L O M F E SION O R R ALLOYS AR O C R A L ANU R G S ON R E R T U N C I C. O N O D I N S A O RIES CORR A D N U OF O B N G N I I S A L R A G N F R O E S EXT PATH T N E N O R P P O L O A S I E R L E A T C A S M C E OF R U L I A F MICROSCOPI N E D S. D U N I S A A R E G B N E A EC BETW N O I S E H O ATTACK. THES C OF S S O L A O T E U ASSEMBLY D er p p o e c c in f n o d a t e n s h o n i c I t a r ipita hich is re grain c � Fo e r p lloy daries w ion near go a r e p er un eg op r d c o n b e u m h e t u d h n s t Alumi es place at nt to it. Thu n anode an � ace aves as a tak j s d e a t a n aluminer that regiocopper behrrosion. co coop daries less � boun

STRESS CORROSION d n a s s e r t s e l i s n e t f o t c e. f l f a e t e d e m n f i o b t m d n o e e t c a m e c n i r o th r b i s a v i f n t I n e i � e l n v e i e k s e c o s i r n r is d n n o a i s c the co o n r i r z o c e f k i l o s e y p o y l t l a is in a t r � Th e c f o y s b e l e c s i u a art c s s e r t s. f r s o o s e g a r c n i b w en s a r e r d p , g e n i h l t l o o r t e e k u i l D g � n i k r o. w g y n i v l a a e e h n n a t n e i c i f f insu

H AS C U S E ECTIV L E L. S E E D T N S A IFIC MILD C R E O P F S TION GHLY U I L H O E S R E TS A RAT T N OF I E N S G E A G D N E A O V I R STR ROS LL G D R A N O N A I C S S E S I S TH BRA D H 2 LKAL N A R A O C I F R T E A S ONI WAT M A 1) CAU M E A S , F SS O UTION E L R O T S S ) E 2 RID O L H C 3) ACID EEL. T S S S E STAINL

WATER LINE CORROSION re diffe f o e p y et sion o r r o c ation r place. t s n e e k c a n t en co rosion g r y o. . The x c E o f C l o A t a L i n t S u n E TAK amo N m u O I m S i x O a RR rt and m a O k p C n c s h a i t t u d c l This is tored in a stee f water menis nd act as catho is s vel o r e e l t ated a a n e e h w t g n y w e x o Wh hly o st bel g i u j h e s i n i l e n Along a e the water li ov area ab affected. ain un