Introduction to Corrosion

Lecture#01

2

Definition

Corrosion may be defined as the destruction of a metal or an alloy because of chemical or electrochemical reaction with its surrounding environment or medium

a metal or an alloy

environment or medium

3

Env

iron

men

ts in

C

orro

sion

1

1Sheir, L.L., R.A. Jarman, and G.T. Burstein, eds. Corrosion. 3rd ed. Vol. 1. 2000, Butterworth-Heinemann: Oxford.

4

Corrosion: Metallurgy in Reverse2

2Fontana, M.G., Corrosion Engineering. 3rd ed. 1986, New York: McGraw-Hill.

Some Corrosion Failure Examples3

3Corrosion Doctors Website. Homepage: http://www.corrosion-doctors.org

6

Aloha Incident

7

Aloha Incident (Contd..)

8

Bhopal Accident

9

Carlsbad Pipeline Explosion

10

Flow Accelerated Corrosion

11

Nuclear Reactor with a Hole in the Head

12

Losses due to Corrosion4

4Uhlig, H.H. and R.W. Revie, Corrosion and Corrosion Control. 3rd ed. 1985, New York: John Wiley & Sons.

13

Cost of Corrosion

Which cost more? Corrosion Fire Flooding Earthquake

14

Cost of Corrosion(2004) in billion US$5Country Direct Cost Indirect Cost USA 303.76 200 (approximately)

Japan 59.02

Former USSR 55.01

Germany 49.26

UK 8.51

Australia 7.32

Belgium 6.75

India 3.78

Poland 3.53

Canada 3.38

.....

.....

.....

Global 510.14 940 (approximately)

5Bhaskaran, R., N. Palaniswamy, and N.S. Rengaswamy, Global Cost of Corrosion—A Historical Review, in Corrosion: Materials, Vol 13B, ASM Handbook. 2005, ASM International.

15

Example of Overdesign3

An 8" in. dia oil pipeline 225 miles long with a in. wall thickness was installed with no corrosion protection system

With appropriate protection namely cathodic protection, it would have a thin wall thickness which would save 3,700 tons of steel (worth more than one

million dollar) increase internal capacity of the pipeline by about

5%.

16

So……Why Study Corrosion?

Materials are precious resources Engineering design is incomplete without knowledge

of corrosion Applying knowledge of corrosion protection can

minimize disasters Corrosion – contaminate products such as

pharmaceutical, food and dairy products or luxury items like soap

Corrosion products – threat to the environment Artificial implants for the human body!!!

17

Distribution of disciplines in which active corrosion engineers have graduated

18

So .. What would be expected from You (a Corrosion Engineer)? Ensuring maximum life of new equipment Preservation of existing equipment Protecting or improving the quality of a product in order to

maintain or improve a competitive position. Avoiding costly interruptions of production. Reducing or eliminating losses of valuable products by spillage

or leaks. Refitting of equipment withdrawn from service because of

corrosion. Reducing hazards to life and property that might be associated

with corrosion: Explosions of pressure vessels or piping systems release of poisonous or explosive gases or vapors are a few examples.