v-xii

5/24/2018 v-xii

1/8

International Conference on Advancements and Futuristic Trends in Mechanical and Materials Engineering (October 5-7, 2012)

v

Punjab Technical University, Jalandhar-Kapurthala Highway, Kapurthala, Punjab-144601 (INDIA)

CORRSION PREVENTION A TECHNOLOGICAL CHALLENGE

U. K. Chatterjee

Professor (Retired), IIT KharagpurAdjunct Professor, BESU Shibpur

ABSTRACT

Corrosion accounts for a substantial damage to the metallic components affecting economy and safety.

Several methods of corrosion prevention are available, the principles of which are essentially based on the

understanding of the mechanism of corrosion processes. While the principles of corrosion prevention

methods are rather simple, their implementation poses technological challenges on many occasions. A few

examples of application of cathodic protection, a widely used method of corrosion control, are provided toelucidate this. Development of a corrosion resistant material or the treatment of a metal or alloy to make it

resistant to corrosion is a challenge to metallurgists and corrosion engineers. The failure, success andinnovation stories in these two areas of corrosion prevention are presented.

1. Introduction

The principles of aqueous corrosion are easy tounderstand. A metal part undergoing corrosion in

an aqueous solution is analogous to an

electrochemical cell (Figure 1), which consists of

four components viz.

1) the anode, where dissolution takes placewith the generation of electrons,

2) the cathode, where the electrons areconsumed through a reduction

reduction,

3) an electrolyte, which is the corrosivesolution itself, and

4) an electrical contact between the anodeand the cathode, which is provided by

the corroding metal itself.

The principles of corrosion prevention are very

much related to our understanding of theprinciples of corrosion and the various corrosion

mechanisms. Some of the obvious approaches

are:

1) to make the metal more resistant tocorrosion or substitute the metal by a

more resistant one in a givenenvironment,

2) to make the environment less corrosive,3) to provide a barrier between the metal

and the environment,

4) to control the cathodic reaction, sincethe rate of anodic dissolution reactionmust be equal to the rate of cathodic

reaction to maintain electrical

neutrality,

5) to modify the metal surface to make itresistant to corrosion,

6) to make the metallicstructure/component cathodic so as to

avoid dissolution, and

7) to change the design of thestructure/component to minimize

corrosion.

The broad corrosion prevention methods based

on these approaches are:

1) Material selection and alloydevelopment

2) Use of inhibitors3) Surface modification by use of

passivators, by chemical conversion

coatings, and by laser/plasma treatment

4) Use of coatings metallic, inorganicand paints

5) Cathodic protection6) Anodic protection7) Change of design.

While in some cases the preventive methods can

be adopted with ease, some other situations pose

5/24/2018 v-xii

2/8


vi


technological problems and demand innovations.

Some of the latter ones are discussed.

2. Cathodic Protection of ComplexUnderground Structures

The principle of cathodic protection is simple.The corroding structure is to be made andmaintained as cathode to avoid dissolution. This

can be achieved either by coupling it with a less

noble metal that acts as a sacrificial anode, or by

impressing a current to the structure from an

external dc source through the use of an auxiliary

anode (Figure 2).

Underground structures in power plants are

usually protected by coatings and impressedcurrent cathodic protection (CP). These measures

may not always be effective in the areas under

and adjacent to the reinforced concrete slabsbeneath the boiler and turbine-generator areas.

The relatively large number of reinforcing rods

in the slabs, which are electrically connected to

the buried structures, can pick up a significant

amount of CP currents, as reported in a case

study [1]. The concrete encased rods have a more

cathodic, or noble, potential than steel normally

attains in soil. Consequently, the reinforcing rods

tend to shield other coated metallic structures inthe vicinity from protective current pick up. The

problem is aggravated further when the complexburied pipings or conduits are run in bundles

through these areas (Figure 3). In this situation,

coated structures in the periphery of the bundle

may further shield the structures near the centre

of the bundle from sufficient CP current pick up,

as shown schematically in Figure 4.

The problem may be tackled by the following

measures:1) By applying a coating of structural grade

concrete instead of conventionally coated steelpipe, the pipe can be made to assume a cathodicpotential similar to that of the reinforcing rods in

the concrete mats. The distance out from the

edge of the concrete mats to the end of the piping

encasement is usually specified as a function ofthe indigenous soil characteristics and geometry

of the structures involved. Beyond this area,

conventional coatings can be used.

2) To ensure protection of the shielded areas,

local CP consisting of ground bed anodes shouldbe installed in the immediate vicinity of these

areas in addition to the operating remote ground

bed. The local CP should be carefully designed

and tested to ensure its efficacy.

3) The corrosion control plans should be

completed during the design stage of the plant.

3. Corrosion Prevention ofReinforcement in Concrete

Normally, carbon steel reinforcement in concrete

is protected against corrosion by passivation

from the high alkalinity in concrete. Corrosion

proceeds only with the loss of passivation, which

may result from either carbonation or the

presence of chloride ions. The volume of the

corrosion product (rust) being 3-4 times that of

the metal undergoing corrosion, internal stressesdeveloped in the concrete evidently leads to

cracking along the lines of reinforcement,

spalling of the concrete, loss of bond, andreduction in member strength. A total collapse of

the concrete structure has also been experienced.

The prevention of reinforcement corrosion poses

a challenge to the corrosion engineers. Some

interesting innovation, failure and success stories

in this area are illustrated and discussed here.

Failure Story 1

Conventional patch repair method of the affected

concrete involves the replacement of the rebar bya new one. However, some chloride ions may

migrate from the old concrete into the new repair

concrete, so there will always be the risk of new

rebar corrosion. Also, the ongoing corrosion of

the rebar in the old concrete cannot be stopped

by this patch repair. Cathodic protection

provides a reliable solution to the corrosion of

reinforcement. The success depends on the use

of auxiliary anodes of appropriate formation anddesign. Anodes consist of conductive coatings on

the surface, mixed metal oxide coated mesh orladders in a concrete overlay, conductiveceramics or mixed metal oxide coated titanium

rods or tubes in the holes in the concrete. The

coatings available range from a variety of

formulation of carbon loaded paints, and thermalsprayed metals such as zinc, or titanium.

The first CP system applied to concrete

reinforcement in Germany was installed at a

retaining wall of the Berlin Highway Ring in1986. The structure revealed several areas of

5/24/2018 v-xii

3/8


vii


spalled concrete with corroded steel underneath

[2]. The corrosion was evidently caused by the

ingress of chlorides from 15 years exposure to

deicing salts. The anode applied to the structure

was a conductive polymer wire (8 mm diameter)

with a core of copper strand (2 mm diameter).The electrical resistance between the copper

strand and polymer surface was 10 ohm. The

anode wires were fixed loop-shaped by means of

plastic dowels at the concrete surface.

The monitoring of the CP system indicated

inadequate polarization after 7 years. The

rectifier voltages were increased, resulting in the

achievement of current densities varying

between 3 and 7mA/m2. During the following

years, the protection current density further

decreased. Finally, the design values could nolonger be reached by increasing the rectifier

voltage after 15 years of service. Parts of the

anode material were removed and examined. Thecopper core was still in the original condition,

but the polymer material showed a considerablechange down to a depth of about 2 mm (Figure

5). The region revealed a layer-like structure;

thin single layers appearing to be separated from

each other. The centre contained a mean carbon

content of about 90%. The outer layer revealed

values of only 74%. Hence, the conductivity ofthe polymer material reduced considerably away

from the centre. The electrical resistance

between copper strand and polymer surface

showed values of about 160 M-ohm.

The observed degradation manifestations aretypical for polymeric anode materials, which

obtained their conductivity from the reaction of

conducting polymers with carbon. The partial

reactions that occur at the anode are:

2OH-H2O + O2+ 2e

H2O 2H++ O2 + 2e

Both reactions reduce pH values and create

oxygen. This reacts with the carbon of the

polymer according to the reaction

C + O2 CO2and yields a reduction of a conductive carbon

content of the anode as the time of operationincreases. The reaction products have virtually

no electrical conductivity; hence, the anodes

resistance increases considerably. The use of

these materials for CP of reinforced concrete

structures has since been discontinued and is notrecommended in the

standard.

Failure Story 2

Alloying of steel is one of the approaches to

increase the corrosion resistance of rebars, whichhas been attempted since long. A marginal

improvement has been reported with the addition

of elements like Cr, Mn and P, totaling not

exceeding 3%. Such steels are being marketed by

steel manufacturers at home and abroad. Anadditional advantage of the alloyed steels is their

high strength, which allows the use of thinner

cross sections. Twisting of the carbon steel

rebars is another way to impart higher strength,

and this procedure was followed by a rebar

manufacturing firm. Apparently, to compete with

the other manufacturers of CRS rebars, thisparticular firm engaged us to develop a low-alloy

corrosion resistant steel. We were marginally

successful; the micro-alloyed steel registerednearly 20% improvement in corrosion

performance in chloride solutions, whilemaintaining the strength of the cold twisted

carbon steel rebars [3]. However, the company

insisted on cold twisting the alloyed steel rebars

as well to maintain tradition. Cold working

induces internal stresses, and due to this, the

corrosion resistance and ductility registered adecrease and the benefit of alloying was lost.

Success Story 1

This is a success story of cathodic protection ofreinforced steel [4]. Corrosion of reinforcementin precast concrete ground-floor elements

containing mixed-in-chloride has become a

major problem in the Nederlands affecting about

100,000 privately owned houses. During the

1960s and 1970s, chloride was mixed into

precast concrete as a set accelerator at typicalcontents of 0.5 to 1.2% by mass of cement.

Passivation is thus compromised. High humidity

led to corrosion and spalling of the concrete.

The strength of the floor elements could be

reinstated by a structural system using steelprofiles, but poor accessibility made the

application difficult. Conventional concrete

repair methods also could not be employed

because of the limited working space. Moreover,

there was no guarantee that the chloride in theold concrete would not aggravate the condition

5/24/2018 v-xii

4/8


viii


of the old rebars and attack the new rebars in the

repaired portions. So, cathodic protection was

adopted for the protection of the structures.

In the precast ground floors, each element

consists of two ribs and a 500 mm wide web.Each rib contains one main rebar 12 mm in

diameter. CP is applied in a series of steps. First,

loose concrete is removed and new bars are fixed

by welding. Then, activated titanium strips are

inserted between and below adjacent ribs (Figure6). Anode strips connections are made by spot

welding bare titanium wires. Welding steel wire

provides continuity between adjacent steel

elements. Semi-tubular plastic forms are placed

below the ribs, and the space around the anode is

filled with flowable cementation grout that

tightly adheres to the old concrete. Wire from theflow fields separated by foundation beams are

collected at the transformer/rectifier, which is

placed in a cabinet near the front door.

The CP system is claimed to be 30% moreeconomical than the conventional structural

system, and an expected lifetime longer than 25

years has been guaranteed.

Success Story 2

This is a success story of stainless steel being

increasingly used as rebars in concrete structures.

One of the North Americas most durable

concrete structures in marine environments is a

60-year old concrete pier, situated in Progreso,Mexico. It is reinforced with 304 stainless steelrebars. It shows no significant corrosion problem

till date, whereas an adjacent pier made of

carbon steel rebar about 30 years ago has

virtually disappeared [5].

The success of stainless steel arises from theunderstanding of the fact that passive film on

stainless steels is more stable. Stainless steels are

subject to pitting, but the chloride content

requirement is high. Laboratory tests have shown

that 304L and 316L have resisted attack up to

6% chloride even after 8 months exposure at 40C and 95-98% relative humidity [6]. Pitting is

the only form of corrosion expected in concrete.

Intergranular corrosion is avoided by the use of

low carbon grade stainless steels. Stress

corrosion cracking occurs under a condition ofhigh temperature, carbonated concrete and heavy

chloride contamination, which are unlikely to

occur concomitantly.

The pitting corrosion resistance of SS bars

depends on chemical composition,

microstructure and surface condition of the steel,on the pH of the concrete and the

electrochemical potential of the steel. A

judicious choice is essential. The pH versus

chloride diagrams [Figure 7] provide an useful

guidance for the application. Since the criticalchloride contents are much higher than the

normal chloride contents of even aggressive

media e.g. marine environments or deicing salts,

stainless steel rebars have found applications in

the joints of bridges, splash zone of marine piles

and marine structures.

Use of stainless steel in new structures is often

limited to the superficial part of the structure (for

skin reinforcement), or to its most critical parts(e.g. bridge joints or splash zones). Coupling

with carbon steels indicates interestingobservation. In concrete, stainless steel has been

found to act as a poor cathode compared to

passivated carbon steel. So, stainless steel is

suggested as a better reinforce material in repair

projects.

As regards the cost effectiveness of the use of

stainless steels as rebars, the following

observation [7] is revealing. The Midland Link

Motorway Viaducts in the U.K. was built in

1972 at a cost of 28 million pounds by usingmild steel rebars. Within two years of building,deterioration of concrete had been observed. By

1989, a total cost of 45 million pounds was spent

on repairs and it was estimated that by the year

2006, a further 120 million pounds would be

required. Thus, a total 165 million pounds will

be spent on repairs. Whereas the estimated firstcost (at 1972 levels) of installing corrosion

resistant stainless steel rebars in critical locations

would have been only 3.4 million pounds.

InnovationThree decades back, few researchers had

considered the possibility of extracting the

chloride from concrete using an electrical field

rather than controlling with cathodic protection.

Electrochemical chloride extraction (ECE) cameinto being in the1980s. Figure 8 shows a

5/24/2018 v-xii

5/8


ix


schematic of an ECE system. The technique uses

a temporary anode and passes a high current to

pull chlorides away from the steel. It resembles a

CP system, but has a few important differences:

1) The anode and wiring are temporary.2) The treatment lasts only 4 to 8 weeks

instead of being permanent.

3) The current level is typically 1 A/m2ofsteel surface area instead of the typical

19 mA/ m2for impressed current CP.

A typical anode system consists of a layer of wet

sprayed cellulose fibre applied to the surface

followed by a mild steel mesh anode and an

additional sprayed fibre on the top. A proportion

(usually 50-90%) of the chloride can be

completely removed from the concrete with very

significant removal immediately around thesteel, and a high level of repassivation of the

steel, is obtained [8].

ECE can be used in many situations where CP

can be applied. It is at its best where the steel isreasonably closely spaced, the chlorides have not

penetrated too much beyond the first layer of

reinforcing steel and future chlorides can be

excluded. It has been applied to highway

structures, car parks and other structures in

Europe and North America.

4. Splash Zone Protection of OffshoreStructures

A splash zone is a part of the offshore structurethat is alternately in and out of water because ofthe influence of tides, winds, and the sea. Since

the areas are intermittently wetted, the CP

system used for the rest of the immersed

structure will not work in this zone. The

influence of winds, tides and sea will ensure an

ample supply of oxygen and removal ofcorrosion products. Therefore, the general

corrosion rate in this zone is higher than the

submerged part of the structure (Figure 9).

Since CP is not reliable in this zone, the normal

protection method combines corrosion allowancewith a coating or, at times, the use of a wear

plate. A recent report of a Norwegian operators

experience in the protection of offshore

platforms [9] relates the technological challenge

met in this regard. For structures with designlives of 12.5 years, a corrosion allowance of 5

mm with a paint coating thickness of 300-600

micron has been worked out to be optimum. For

some old platforms, a high-build epoxy system

reinforced with glass flakes or sand has been

used. For the corrosion control of risers, where

the operating temperature is higher, a 2 mmcorrosion allowance with a 12 mm vulcanized

chloroprene rubber has been used.

WE had ventured to device a cathodic protection

system for the splash zone on a laboratory scale[10]. The schematic view of the experimental

set-up is shown in Figure 10. The electrolyte, a

3% sodium chloride solution, was allowed to

flow from a bottle into the cell through a stop

cock control.A siphon arrangement was provided

to drain out the electrolyte from the cell. The

flow rate was so adjusted that the cell was filledup in about 15 min time and the electrolyte was

drained out in the next 15 min. In this way, the

splash zone condition was simulated withperiodic wetting and exposure to atmosphere.

The specimen, a 0.12% carbon steel, was

assembled with a steel wire mesh of size 55 over

it with two plastic strips in between at the edges

so that the specimen and the wire were not in

direct contact, but contact could be made only

through the thin electrolyte film formed inbetween. The wire mesh also served as auxiliary

anode. A thin glass rod was placed lengthwise on

the wire mesh and clipped to the specimen ae the

ends by means of plastic clips to provide a

uniform spreading of the wire mesh over thespecimen and also to keep the assembly intact. Atransistor power supply was used as dc source,

and the potential was measured with the help of a

VTVM.

Currents of 0.023 to 0.136 mA/cm2were applied

for 24 hr. The samples were thereafter cleaned,dried and weighed, and the percent protection

was calculated with respect to the weight loss of

a dummy specimen. The maximum protection of

96% was obtained at a current density of 0.136

mA/cm2.

5. Corrosion Control of Railway Coaches

Corrosion of the passenger coach body has

remained a long-standing problem with the

Indian Railways. There have been cases of toiletfloor collapse, which has largely been mitigated

5/24/2018 v-xii

6/8


x


by design changes and improved flooring.

Corrosion of sidewalls at the floor level is a

major problem. The coach body before 1976 was

made of mild steel of copper bearing quality. In

1976, ICF switched over to using low alloy high

tensile corrosion resistant CORTEN steel. Thischange over increased the service life of the

coach to 7-10 years from 5-6 years before going

for corrosion repairs in the workshop. The

repairing job requires withdrawing of the coach

from service, consequently reducing theavailability of the coach for passenger service. In

the normal 25 years life expectancy of the coach,

it is sent to workshop for corrosion repairs two to

three times. The special corrosion repair is time

consuming, and the cumulative cost of coach

repair is enormous.

The first ever stainless steel body railway coach

made by ICF was flagged off in November 1999

[11]. Stainless steel was used for all componentsof the shell consisting of the under frame, trough

floor, side wall, end wall and roof except forcross bearers, headstocks, body bolster and

compartment partition frame. Approximately 11

metric tons of austenitic stainless steel

conforming to AISI 301 grade was used in the

making of the shell of this coach. The need for

corrosion repair has been reduced. Thisexperience has boosted the use of stainless steels

for coaches. Dehli Metro Rail coaches are almost

exclusively made of stainless steels. The

corrosion damage of the side walls at the

flooring level is likely to occur in stainless steelas well. Therefore, the challenge continues toexist in this area. A detailed analysis of the

causative factors including the design

consideration may help find a wider use of

stainless steels.

6. Metallurgical Challenges

Rusting of steel, the most important structural

metal, has always been a problem since the days

of its earliest use. In atmoshpheric exposures, the

porous and non-adherent corrosion product (i.e.

rust) tends to flake off exposing the bare metal,and thus leading to further corrosion. The

addition of a few tenths of copper to steel has

been found to be beneficial, since this produces a

rust which is more compact and adherent to the

base metal. Low-alloy and micro-alloyed steels,which have been developed, aim at achieving a

combination of strength and corrosion resistance

in the structural components.

The dream of making the steel rust free came

true with the invention of stainless steels. The

requirement of a minimum chromium contentwas established. However, it was soon realized

that stainless steels are not the answer to all

corrosion problems, rather they themselves are

vulnerable to certain specific corrosion

problems. The problem of pitting could beminimized with the addition of molybdenum.

The problem of weld decay was also tackled

metallurgically, by stabilizing the stainless steels

with titanium, niobium or tantalum. Even the

stabilized stainless steel becomes susceptible to

intergranular corrosion (knife-line attack) under

certain post-welding heat treatment conditions. Aremedial heat treatment is needed to counter the

problem. Austenitic seainless steels are

susceptible to stress corrosion cracking (SCC) inchlorides or polythionic acid. The metallurgical

solution is to use ferritic or duplex stainlesssteels under such circumstances.

Stress corrosion cracking of end-retaining rings

in power generating plants posed a serious

problem during the eighties. The catastrophic

failure of a ring inside an operating machine hasresulted in extensive and costly damages in

terms of long shutdown periods of of the

machine. The conventional material was an

austenitic steel containing 0.3-0.6 C, 17-20 Mn,

3-6 Cr. Investigations [12] revealed that massivecarbide precipitation produced in this steelduring the manufacturing stage is soluble in

chloride solutions. This leads to the formation of

pits, which act as sites for stress corrosion

cracking. Replacement of the steel by a low

carbon high chromium variety (0.1 C, 17-20 Mn,

17-20 Cr) has since mitigated the problem.

In the realm of stress corrosion cracking of high

strength aluminium alloys used for aircraft

applications, the mitigating means by alcladding

is an example of well known metallurgical

success. Since the pure metals are almostimmune to SCC, a thin sheet of pure aluminium

adhered to the surface of duralumin by rolling

would protect the latter from SCC.(The stainless

steel cladding of carbon steels, incidentally, can

be more economical than the use of an all-stainless steel part in some corrosion

5/24/2018 v-xii

7/8


xi


applications). A new heat treatment,

retrogression and reaging (RRA), was invented

and put in practice for reducing the susceptibility

of the 2000, 7000 and 8000 series alloys to SCC

[13}. An overage temper of these alloys is

acceptable from SCC point of view, but due totheir lower strength one has to bear a weight

penalty of about 15%. The principle of the RRA

treatment is to heat treat the alloy in the peak age

temper to just above the solvus line promoting

the dissolution of matrix strengtheningprecipitates. Reaging the retrogressed state

brings back the precipitates in the matrix

resulting in the retention of the peak age

strength. Further, reaging causes growth of the

existing equilibrium precipitates and their re-

precipitation at the grain interior, sub-grain

boundaries and grain boundaries improving theSCC resistance. The work at our laboratory on

1441 and 8090 Al-Li alloys confirms such

improvements [14,15].

Microstructures influence various properties ofmetals and alloys, including their

electrochemical behaviour. In a multiphase

system, the electrochemical difference of the

phases is often the cause for enhanced corrosion

due to a galvanic effect, as is encountered in

usual reinforcing bars having pearliticmicrostructure inside concrete. The problem has

been attempted to be metallurgically solved by

changing the microstructure to a ferritic matrix

with discrete lath martensite [Fig. 10] (16).

Dissolution or redistribution of the phases, asdiscussed in the previous paragraph, can lead toan improved corrosion resistance. In a leading

power plant in the country, pumps made of

Hastelloy were in operation for handling some

strong caustic liquid. The pumps were being

imported from abroad, and the management

sought an indigenous substitute. A Mumbai-based firm came forward to supply pumps made

with the material of right composition, but they

were failing prematurely in service. A

metallurgical failure analysis indicated a

difference in microstructure in the imported and

indigenous materials. Obviously, the indigenouspumps lacked in proper heat treatment.

That the microstructure also influences hydrogen

embrittlement of steels was demonstrated

through the pioneering work of Burnstein and hisgroup [17]. The cathodic reaction in the

corrosion process is one of the sources of

hydrogen entry into the metal. Cathodic

protection of the ship hull by galvanic coupling

with zinc also provides the source of hydrogen.

Our investigations with the naval steels, HSLA-

80 and HSLA-100, have shown that a purelyacicular ferritic or lath martensitic structure

offers a greater resistance to hydrogen

embrittlement, while a mixed bainitic-martensitic

structure is most vulnerable [18,19]. Welding

produces a varied microstructure in the heat-affected zone and thus may give rise to an

Achilles Hill in the welded metal from

hydrogen embrittlement point of view. The work

has demonstrated the possibility of attaining the

most desirable microstructure through the

selection of proper welding parameters.

The broadening of the scope of surface

modification through laser or plasma treatment

has opened up endless possibilities of enhancingthe corrosion resistance of components made of

common structural metals and alloys. A surfacealloying of steel components with chromium

would eliminate the use of the more expensive

stainless steel for the entire component. An

improved surface hardness attained through

surface alloying with chromium and tungsten

would make the component more adaptive toerosion corrosion applications, as has been

demonstrated by laser surface alloying of copper

with chromium [20]. Amorphization of the

surface by laser or plasma treatment provides

another possibility of enhancing the corrosionresistance of components. The better corrosionperformance of amorphous metals has been

demonstrated in many publications and also in

our investigation on splat cooled Zr-Pd and Zr-Pt

alloys [21]. The improvement is primarily due to

defect free and compositionally homogeneous

microstructure with no grain imperfections orboundaries that provide active anodic sites for

corrosion to initiate and spread. The corrosion

performance of nanostructured components has

also been observed to be superior to the

components having the conventional grain size

[22], and in some cases, nanostructured alloyshave shown better corrosion resistance than their

amorphous counterparts [21,23]. Although the

scope of surface amorphization or production of

bulk metallic glass and nanostructured materials

is presently confined only to small components,

5/24/2018 v-xii

8/8


xii


their widespread application remains a

technological challenge for the future,

7. Conclusion

Aqueous corrosion is an electrochemical

phenomenon, but its mitigation or controlinvolves chemistry, metallurgy and engineeringas a whole. It is difficult to meet all the

technological challenges of corrosion prevention

by an individual trained in a particular field. A

team of trained personnel in various fields may

be required in critical cases.

References

1. Joram Lichtenstein, Materials Performance, 40, Nov.(2001), pp 20-22

2. J. Mietz, J. Fisher and B. Isecke, Materials Performance,

40, Dec. (2001), pp 22-26

3. U.K. Chatterjee, K. Banerjee and A.K. Chakrabarti,

Proceedings of the International Conference on Constrution

Management and Material (CONMAT- 2003), IIT

Kharagpur, Jan. 2003, pp 511-515

4. Geard Schuten and Jan Leggedoor, Materials

Performance, 40, Jan. (2001), pp. 22-24

5. Stainless India, Vol. 5, No. 4 (1999), p.3

6. Luca Bertolini and Pietro Pedeferri, Corrosion Reviews,

20 (2002), pp 129-152

7. Seainless India, Vol. 5, No. 2, (1999), p.4

8. John P. Broomfield, Materials Performance, 41, Jan.

(2002), pp 52-54

9. Rolf E. Lye, Materials Performance, 40, April (2001), pp

40-45

10. S. Palaniappan, U.K. Chatterjee and S.C. Sircar,

Proceedings of the 4th Asian-Pacific Corrosion Control

Conference, Tokyo, May 1985, pp 1198-1203

11. Stainless India, Vol. 5, No. 2, (1999), p.2

12. N. Mukhopadhyay and U.K. Chatterjee, Trans. Indian

Inst. Metals, 50, (1997), pp 49-58

13. B.M. Cina, Reducing the susceptibility of alloys

particularly aluminum alloys to stress corrosion cracking, U.

S. Patent 3,856,584, Dec. 1974

14. K.S. Ghosh, K. Das and U.K. Chatterjee, Metallurgical &

Materials Trans, 35A (2004), pp 3681-3691

15. K.S. Ghosh, K. Das and U.K. Chatterjee, Metallurgical &

Materials Trans, 36A (2005), pp 3477-3487

16. John Crips, Corrosion is one of the biggest losses the

nation endures, MMFX Steel Corporation of America, August

2000

17. I.M. Bernstein and A.W. Thompson, In Hydrogen

Embrittlement and Stress Corrosion Cracking (Eds. R.

Gibala and R.F. Hehemann), ASM, 1984, pp 135-152

18. Kumkum Banerjee and U.K. Chatterjee, Proceedings of

the International Conference on Processing and

Manufacturing of Advanced Materials (THERMEC 2000),

Las Vegas, 2000; CDROM, Section C3, Vol. 117/3 Special

Issue: Journal of Materials Processing Technology,

Elsevier Science, U.K., 2001.

19. K. Banerjee and U.K. Chatterjee, Metallurgical &

Materials Trans, 34A (2003), pp 1297- 1309

20. I. Manna, J. Dutta Majumdar, U.K. Chatterjee and A.K.

Nath, Sripta. Mater., (1996), pp 405-41021. K. Mondal, U.K. Chatterjee and B.S. Murty, Corrosion

Science, 47 (2005), pp 2619-2635

22. M. Naka, K. Hashimoto and T. Masumoto, Corrosion, 36

(1980), pp 679-686

23. D. Szewieczek, J. Tyrilik-Held and Z. Paszenda, Process

Tech., 78 (1998), pp 171-176

.

v-xii

Documents