CORROSION… The Best Kept Secret in the Western World Terry May President, NACE Foundation Introduction Not a professional educator Engineer and training instructor New addition to curriculum Important but unknown topic Corrosion, rust, oxidation, deterioration, cancer? Why is this important?

Corrosion & Society Discuss the 3 Primary effects of corrosion and how it affects our society

Corrosion & Society Discuss the 3 Primary effects of corrosion and how it affects our society

Corrosion & Society Discuss the 3 Primary effects of corrosion and how it affects our society

Cost of Corrosion in 1998 GNP Give Background on Cost of Corrosion Study and Primary Results

Money To put in perspective – the annual cost of all the natural disasters in the USA. (Hurricanes, tornadoes, tropical storms, floods, fires etc) $17 Billion Corrosion Costs the US economy $276 Billion per Year or 16 times as much as all the natural disasters combined More than $1000/year/person

25+% could be saved using existing technologies Money 25+% could be saved using existing technologies

Environment 500,000+ miles of pipelines in the US

Environment

Safety Bellingham, WA 1999 Pipeline explosion killed 3 people

Safety Carlsbad, NM

Safety Air Aloha

Safety Lowes Motor Speedway 15% of almost 600,000 bridges in the USA are structurally deficient because of corrosion

Application to Various Industries Pipelines Underground Storage Tanks Industrial Plants Power Generation Transportation Marine Waterworks Petrochemical Plants Pulp and Paper Real Estate Private Homes

What is Corrosion? Corrosion is an electrochemical reaction between a metal and its environment Corrosion is the tendency of a metal to return to its original state Corrosion involves the flow of DC current Corrosion is a natural process

What causes Corrosion? Dissimilar metal Differential Aeration Environment concentration differences Bacteria Stress Erosion Temperature effects

What does Corrosion look like? Uniform Pitting Stress Cracking Intergranular Crevice Attack Erosion-Corrosion

General Corrosion

Pitting

Crevice Corrosion

Galvanic Corrosion

Practical Galvanic Series Magnesium -1.6 Volts Zinc -1.1 Aluminum -1.05 Steel (clean or shiny) -0.5 to -0.8 Steel (rusty) -0.2 to -0.5 Cast Iron -0.5 Lead -0.5 Copper or brass -0.2 Mill scale on steel -0.2 Carbon or graphite +0.3 ACTIVE Standard electromotive series based on standard hydrogen reference. Galvanic series may vary slightly and are specific to an environment PASSIVE

Flashlight Battery An engineered corrosion reaction Zinc/Carbon cell connected with a conductive electrolyte Life depends on current load

Graphite-Zinc Battery Protective casing Pitch Seal Electrolyte paste (ammonium chloride and zinc chloride) Air Space Zinc Separator Carbon rod Negative terminal

What conditions are required for corrosion to occur? An anode and a cathode – locations with a difference in electrical potential (voltage) between them A metallic connection between the two points Both locations exposed to the same environment

Four Conditions of a Corrosion Cell Anode - where oxidation occurs Cathode - where reduction occurs Electrolyte - where ion migration occurs Metallic path - where electrons migrate from the anode to the cathode

Single Corrosion Cell e- e- e- e- e- e- e- e- e- e- e- CATHODIC SITE Microscopic View CATHODIC SITE ANODIC SITE e- e- e- e- e- e- e- e- e- e- e- H Fe++ Fe++ H H+ H+ Fe++ H Fe++ OH- H+ Fe++ OH- H+ H+ Fe++ OH- H+ Fe(OH)2 Fe(OH)2 H+ Fe(OH)2

The Corrosion Cell Metallic corrosion is an “electrochemical reaction” which involves : a transfer of electrons oxidation - loss of electrons (corrosion) reduction - gain of electrons (protection) migration of ions

Corrosion Cell Electrolyte Metallic Path e e Cathode Anode e e H+ H+ Cu Fe e e H+ H+ Fe++ H+OH— Electrolyte H+OH—

Structure (metallic path) Practical Case Showing Conventional Current Flow E Corrosion Current Electrolyte (soil) Cathode Anode Structure (metallic path)

Electrochemical Reactions Anode: (Oxidation) Fe  Fe++ + 2e— Cathode : (reduction) 2H+ + 2e—  H2 3O2 + 6H2O + 12e– 12OH— O2 + 4H+ + 4e—  2H2O Electrolyte H2O  H+ + OH—

Oxidation Reaction Anodic Process ANODE ELECTROLYTE e e e e e e e e e - e - e - ++ Fe e - e - e - e - Fe ++ e - Fe ++ e - Fe ++ Fe ++ e - ANODE e - e - Fe ++ e - Fe ++ e - e - e - e - Fe ++ e - Fe ++ Anodic Process

Reduction Reaction CATHODE Cathodic Process ELECTROLYTE e e e e e e e - H + e - H + H H H H e - e - e - H + e - H CATHODE e - H + H + e - + e - H + e - H H + e - e - H + e - e - H + H + e - H + e - e - H + H Cathodic Process

Current Flow in a Basic Galvanic Cell

Methods of Corrosion Control Coating Cathodic Protection Environment Control Material Selection Design

Microscopic View of a Corrosion Cell Anode Cathode Microscopic Corrosion Cell on the Surface of a Pipeline

Cathodic Protection on a Structure (Macroscopic view) Anode Cathode Metallic Connection Electrolyte Cathodic Protection Anode Cathodic Protection Current Applied

Typical Application of Cathodic Protection Underground pipelines Underground storage tanks Bottoms of on grade storage tanks Interiors of water storage tanks Condenser and heat exchanger water boxes Reinforced concrete Doesn’t work in the atmosphere (Automobiles) Underground pipelines Underground storage tanks Bottoms of on grade storage tanks Interiors of water storage tanks Condenser and heat exchanger water boxes Reinforced concrete Doesn’t work in the atmosphere (Automobiles)

Preserving the Past

Preserving the Past Give examples of corrosion control technologies for protection of Titanic artifacts

Preserving the Past Give examples of corrosion control technologies for protection of Titanic artifacts

Statue of Liberty Discuss preservation of Statue of Liberty

Just Flying along, enjoying the ride.... what's so cool is they actually pay  me to do this! 

Hmmm. Strange sound. Something feels different.

Hey, why am I looking up.??

Whoa here, what the hell? Controls aren't working

Time for a mirror check. Hey, where's the rest of my F-15.?

Uh oh, it's over there. I think I've got a definite "Aw, sh Uh oh, it's  over there.  I think I've got a definite "Aw, sh*t" going here...

I gotta wonder, am I the first guy to ever  experience " cockpit-airframe separation anxiety".

I'm outta here. But first the canopy has to go.

Hey GREAT! That worked as advertised. Things are looking up!

OK, now it's my turn to go.  I'm gone - soon as I  find the eject handle.

Oh yeah, that's what I'm talking about Oh yeah, that's what I'm talking about.   Looks like it's going to be just another "average day at the office."