Environmental Degradation and Environmental Degradation and

its Prevention its Prevention

“Metallurgy for Practicing Engineers” (MEPE – 2020)

31st Jan – 1st Feb 2020

Dr S. NingshenIndira Gandhi Centre for Atomic Research

Kalpakkam – 603 102, TN, INDIA

Safety, Economic and Conservation

Most materials decay over time (1/2) Environmental Degradation of MaterialsEnvironmental Degradation of Materials

Type of decay Fungi Rust Cracking/

Spallation

Material Wood Steel Concrete

Spallation

Mitigating actions Chemicals paint/varnish Galvanizing /Painting Corrosion resistant rebar

Y. Li, et.al (2019)

Most materials decay over time (2/2)Most materials decay over time (2/2)

Type of decay Wear

Damage by pollution

Breakage Brittle under UV light

Material Stone Glass Polymer

Mitigating actions Usually none taken Tempered glass Improved polymer grades

Type of decay Pitting and galvanic Green patina Corrosion resistance

Mitigating actions Can be prevented Tempered glass -

Material Aluminum Copper Stainless steel

Corrosion - Disease to Engineering Materials

�Corrosion is an irreversible interfacial reaction of material(metal, ceramic, polymer, etc.) with its environment (i.e.,chemical or electrochemical) resulting to the deterioration ofmaterials or component properties.

.

The interaction can be of the following types:• Physical : Metals in liquid metals.• Chemical : Iron at high temperature in air.• Electrochemical : Iron in water.

Build-up of the rust layer on steel. Corrosion Atlas Case Studies, ( 2020).

Sites for Corrosion Failures Sites for Corrosion Failures -- Surface ImperfectionsSurface Imperfections

SOURCE: University of Virginia Center for Electrochemical Science and Engineering, DerekHorton & Hongbo Cong.

An assessment of the risk of corrosion

�The various forms of corrosion that can be initiate under various industrial and operation condition.

Forms of Corrosion under various Industrial Environ mentsForms of Corrosion under various Industrial Environ ments

Examples Examples -- Environmental Degradation Environmental Degradation Corrosion Deposit sample covered with

Crude Oil

S S Al-Jaroudi, et.al., (2011)

M. Katinić, et. al (2019)

Fracture surface of the rotor blade roots 13Cr stainless steel

Examples Examples -- Environmental Degradation Environmental Degradation

Iridium Iridium -- The Ultimate in Corrosion ResistanceThe Ultimate in Corrosion Resistance

Rob Francis (2018)

Iridium is a hard, brittle member of the so-called platinum group of metals in the periodic table.

Iridium

�However, attacked by some molten salts, such as sodium cyanide and potassium cyanide, as wellas oxygen and the halogens (particularly fluorine) at higher temperatures.

Philadelphia oil refinery to close: What you need to knowhttps://www.inquirer.com/business/philadelphia-refinery-fire-oil-energy-solutions-close-20190626.html (June 28, 2019)

Following a series of explosions and a catastrophic fire….Philadelphia Energy Solutions - the largest oilrefinery on the East Coast - isshuttering its South Philadelphia facility … laying off more than 1,000employeesand causing gasoline futures to spike.

6-Figure Penalty Sought for PSM Violations at Philadelphia RefineryBy Guy Burdick Jan 27, 2020 Energy, Enforcement and Inspection

Dale_Stagg / iStock / Getty Images Plus / Getty Images

The U.S. Chemical Safety and Hazard Investigation Board (CSB) found that a pipe elbow in the refinery’s alkylation unithad corroded to half the thickness and burst, releasing process fluid that included over 5,000 pounds ofhydrofluoric acid.

After rap, After rap, GAIL to install corrosion monitors in pipelines GAIL to install corrosion monitors in pipelines (Economic Times, 29(Economic Times, 29thth July, 2015) July, 2015)

� A GAIL pipeline near Nagaram village in Tatipaka district of Andhra Pradesh, June 27,2014 exploded and caught fire after agas leak caused by corrosion, (29 persons).

Failure Modes in Chemical Process IndustriesFailure Modes in Chemical Process Industries

Component Failure FrequencyComponent Failure Frequency

Failure Statistics in Germany (a)& USA (b)

(a) (b)

Corrosion will cost the US economy over $1.1 trillion (2016).

• 1950 H.H. Uhlig – US Study: 2.1% of GNP

• 1970 T.P. Hoar – UK Study: 3.5% of GNP

• 1974 Japan Study: 1.2% of GNP

• 1975 Battelle/NBS – U.S. Study: 4.5% of GNP

Cost of Corrosion – Previous Studies

India loses Rs 2 trillion annually to corrosionof infrastructure – CII, 3 rd September, 2016, Economic Times. http://economictimes.indiatimes.com/news/economy/finance/india-

loses-rs-2-trillion-annually-to-corrosion-of-infrastructure-government/articleshow/48792499.cms

Corrosion Map of India

The corrosion rate of Metals

Corrosivity Survey of India

Mild steel panel exposed at Chennai Naval Base over a period of eight months

INSIDE VIEW OF FAST BREEDER REACTOR

It is important to ensure the integrity of the structural material over the service period through appropriate evaluation, based on the characteristics of phenomena occurring in the sodium

environment.

Material Degradation in Molten SodiumMaterial Degradation in Molten Sodium

Christian LATGE, (2012)

Microstructures of Sodium Exposed type 316LN SS Microstructures of Sodium Exposed type 316LN SS

The microstructures of sodium exposed 316LN SS after exposure for (a) 16000 h, (b) 30000 h and (c) 40000 h at 525 °C.

The presence of a surface modified layer of ferrite to about 5-10 µm thickness

RAISING THE BAR ON COAL PLANT EFFICIENCYUltra-Supercritical & Advanced Ultra-Supercritical Technol ogy

https://www.ge.com/power/steam/steam-power-plants/advanced-ultra-supercritical-usc-ausc

Material Degradation Issues in AUSC BoilerMaterial Degradation Issues in AUSC Boiler

Y. Fukuda, (2011)

Important materials performance limitations in AUSC Environments are creep strength, high temperature fire-side corrosion and steam-side oxidation

resistance.

Corrosion Problem

O&M Corrosion Cost

$ Millions

Depreciation Corrosion

Cost$ Millions

Total Corrosion

Cost $ Millions

Waterside/Steamside Corrosion of Boiler Tubes

916.0 228.4 1,144.4

Turbine CF & SCC 458.0 142.8 600.8

Corrosion issues for CoalCorrosion issues for Coal--Fired Power Plants Fired Power Plants

Oxide Particle Erosion of Turbines 274.8 85.7 360.5

Heat Exchanger Corrosion 274.8 85.7 360.5

Fireside Corrosion of Waterwall Tubes 183.2 142.8 326.0

Generator Clip to Strand Corrosion 183.2 28.6 211.8

Copper Deposition in Turbines 91.6 57.1 148.7

Fireside Corrosion of SH & RH tubes 91.6 57.1 148.7

K. Coleman & Syrett, et al. (2007).

Fireside Corrosion IssuesFireside Corrosion Issues

� Fireside corrosion of boiler tubes (i.e.,superheater, reheater, waterwalls, economizer,etc.) continues to be the#1 issue resulting inforced outages and boiler unavailability forconventional coal-fired fossil boiler powerplants.

Typical boiler wastage rates are:� Subcritical - 20 mils (0.5mm)/year� Supercritical – 40-100 mils (1.0-

2.5mm)/year

K. Coleman, et. al.(2007).

plants.

Steam-Side Oxidation and Exfoliation in AUSC

Boiler Tubes

Tube blockage (a) and erosion damage to a valve stem (b), both due to thepresence of exfoliated steam-grown oxides in utility boilers. J.P. Shingledeckerand B.A. Pint, (2013)

Corrosion Preventive Measures

� Corrosion can be prevented through good practices in materials selection anddesign,while others can be cured or controlled if diagnosed early.

� 25 to 30% of annual corrosion costs could be saved by optimum corrosion managementpractices.

� Consequences of corrosion- many serious economic, health, safety, technological, andcultural consequences to our society.

Akzo Nobel

Good Engineering PracticeGood Engineering PracticeSelect material/environmental combination based on experience

• Reduce service and residual stress

• Follow procedure/code/practice in Design/Fabrication/Operation

Control of EnvironmentControl of Environment

� Control of Impurities - Remove a cathodic reactant (e.g. water)Add inhibitors which from a protective layer

Design modifications & Design modifications & Improve MaterialImprove Material

Strategy for Prevention of CorrosionStrategy for Prevention of Corrosion

Design modifications & Design modifications & Improve MaterialImprove Material

� Design of structures�Alloying element to reduce scaling

Adopt Protective MeasuresAdopt Protective Measures

Protective Coating - (metallic, inorganic, nonmetallic, or organic coatings),� Plating, etc.

CathodicCathodic protectionprotectionUse a sacrificial anode

Coatings for Corrosion Protection

• Improved corrosion resistance through barrier or sacrificial protection

• Improved oxidation resistance• Improved wear resistance• Improved mechanical properties• Improved electronic or electrical properties• Improved thermal insulation• Improved aesthetic

Paint and CoatingsPaint and Coatings

� In terms of value, global sales of architectural coatings reached $60 billion in 2014.�The majority of the market value was generated by sales of vinyl/styrene/VAE paint, followed by

pure acrylic paint.

https://www.coatingsworld.com/issues/2016-08-01/view_features/asia-pacific-report-371163/

Surface Engineering for Surface Protection Surface Engineering for Surface Protection

Surface coating

Gaseous state

Solution state

CVD

PVD

IBAD

Painting

Electrodepositing

Chemical solution

Plasma variants

Chemical reduction

Electrolessplating

K. Holmberg and A. Matthews, (1994).

coating method

Solution state

Molten orsemi-molten state

Chemical solution reduction

Sol gel

Powder coating

Laser

Thermal spraying

Welding

Plasma variants

Electrolessplating

Chemical reduction

Plasma Spray ProcessPlasma Spray Process

SubstrateSubstrate

Plasma Torch Deposition process

� Plasma spraying process utilises the latent heat of ionizedinert gas (Plasma) to create intenseheat source. Mostly argon is used as plasma gas (primary gas).

� Plasma arc is created between a coaxially aligned tungsten cathode and copper anode (nozzle) bydirect current, which ionizes the gas stream. This generates plasma with very high temperaturesand high velocities due to expansion of gas.

� The temperature of powder particle in plasma spray is as highas 5000°C and velocity is up to 300m/s.

Thermal Spray Process Thermal Spray Process -- Classification Classification

THERMAL SPRAY

COMBUSTION ARC KINETIC

HighVelocity

LowVelocity

Wire arc spray Plasma

Cold spray (also known as Cold gas Dynamic

spray or Kinetic spray)

Direct current (DC)

Flame spray

HVOF

HVAF

D-gun TM Atmospheric VacuumInert Shroud

spray or Kinetic spray)

Radio frequency (RF)

Plasma Spraying Plasma Spraying -- Thermal Spraying MarketThermal Spraying Market

P. Hanneforth, (2005)

General Applications of Functional Categories• Thermal Barrier Coatings(TBC) • Chemical Barrier Coatings(CBC) • Environmental Barrier Coatings (EBC)• Protection against Corrosion and Oxidation• Protection against Wear, Erosion and Cavitation• Electrical Insulation, Abradable, Seal/Clearance Coatings -

Optical, Magnetic and Emissivity.• Biomedical implants -Restoration of worn out components,

etc.

Application Sectors:• Power- Gas turbines, Steam turbines, Boilers, Nuclear• Automotive- Cylinder block, piston, rings, cam, valves,• Automotive- Cylinder block, piston, rings, cam, valves,exhaust

• Industrial- Compressors (shafts, nozzle, cylinder, seals,screws), Metal forming (rolls, dies, stamps, shears), Printingtextile( rolls, guides)

• Oil and gas (Valves, sucker rods, pump components)• Constructions ( Zn and Al coating on steel structures)

� CBC Yttria coating for U melting / Cathode Distillat ion.

� Electrical Insulating Alumina Coating for Neutron D etector / DCCP.

� Corrosion Resistant Zirconia Coatings for Electro-re fining and Molten Salt Purification.

� TBC Ceramic Coatings for Sacrificial Core Catcher f or Future FBR’s.

� Oxidation resistance protective NiCrAlY, Ni-Cr Alloys Coatings, etc.

In-house Applications

� Oxidation resistance protective NiCrAlY, Ni-Cr Alloys Coatings, etc.

� Wear/Erosion Resistant Cr 3C2-NiCr, WC-Co, etc Coatings for AUSCapplication.

Alumina coating on all sides of SS 430 crucibles for Liquid Cd cathode application

Yttria coating on HDG crucibles by plasma spraying for U-Zrmelting crucible.

Cathodic Protection

� Cathodic protection (CP) is a technique to control the

corrosion of a metal surface by making it work as a

cathode of an electrochemical cell.

� Cathodic protection systems are most commonly

used to protect steel, water or fuel pipelines and

storage tanks, steel pier piles, ships, offshore oil

platforms and onshore oil well casings.

The rate of corrosion reactions controlled by passing anodic or cathodic currents into the metal.

Types of CP:Sacrificial anodes (zinc, magnesium or aluminum):The sacrificial anodes are more active (morenegative potential) than the metal of the structurethey’re designed to protect.Impressed current CP: done for large structures(pipes, offshore platforms, etc) where a galvanic (orsacrificial) anode can not economically deliverenough current.

Cathodic Protection of Structure

Benefits of Galvanic Corrosion Benefits of Galvanic Corrosion

� The potential and current between dissimilar metals is usedin a sensorfor timeof wetness in atmospheric corrosion testing.

� Special materials that can generate high galvanic corrosion currents have beenprepared in powder form. When wetted, these powders result in galvaniccorrosion rates that are so high that significant heat is generated. This is howmeals for the U.S. Armed Forces, calledMREs(meals ready to eat),are heatedin thefield: justaddwaterto getahotmeal.in thefield: justaddwaterto getahotmeal.

� Galvanic corrosion is the basis for the operation of mostbatteries.

� The cathode in a galvanic couple frequently has its corrosion rate decreased as aresult of the couple. This is the basis for sacrificial anodecathodic protectionused widely in seawater and soils to protect steel structures.

The Cost of Corrosion Protection in ChinaThe Cost of Corrosion Protection in China

B. Hou, et.al., npj Materials Degradation (2017)

Corrosion Management ElementsCorrosion Management Elements

Corrosion management should be an integral part of the continuous improvementprocess, including prioritization and allocation of resources. (NACE-2016).

RISK ASSESSMENT

PLANNING • Inspection • Monitoring • Mitigation

IMPLEMENTATION • Implement and

execute plans • Define KPIs

IMPROVE • Performance

Review • Review Plans • Take Actions

Corrosion Management in an Operating plantCorrosion Management in an Operating plant

MEASURE • Measure and

Evaluate Data • Status Reports

� There is no ‘right’ method of corrosion control, only the most appropriate one, orones, for a given situation.

� Effective corrosion control measures result from excellent corrosion managementtechniques based on a scientific basis.

� There is no ‘right’ method of corrosion control, only the most appropriate one, orones, for a given situation.

� Effective corrosion control measures result from excellent corrosion managementtechniques based on a scientific basis.

�Metallic corrosion seriously affects a wide spectrum of industries as a result ofcombination of materials, environments and service conditions.

� Corrosion has severe economic consequence and the cost in terms of lives,equipment, and time is very high.

�In order to control corrosion of materials, it is important to understand theinherent factors involve about the nature of corrosion, mechanism of corrosion,forms and types of corrosion encounter and methods involve in prevention of

SUMMARYSUMMARYSUMMARYSUMMARYSUMMARYSUMMARYSUMMARYSUMMARY

forms and types of corrosion encounter and methods involve in prevention ofdifferent forms of corrosion.

�Although corrosion is inevitable, its cost can be considerably reduced by adoptingmany existing technology and methodologies that are available.