After my original article on corrosion definitions, several colleagues shared their own opinions about how we could (re)define not only the term corrosion but also the corrosion science and engineering field as a whole.
This post summarizes their personal views and opinions and it should not be taken as a formal or a standard definition.
Definitions
Jaime Torres E.: Corrosion is the destructive attack of a material by reaction with its environment. Source: Handbook of Corrosion Engineering by Pierre R. Roberge – McGraw Hill (buy at Amazon).
Te-Lin Yau: The chemical or electrochemical reaction between a material and its environment that produces a deterioration of the material and its properties. Source: ASM Handbook, Volume 13A Corrosion: Fundamentals, Testing, and Protection, ASM, Materials Park, OH 2003 (buy at Amazon).
Almost all definitions are totally negative about corrosion. Indeed, corrosion may result in many beneficial outcomes. A few examples are anodic (cathodic) protection, certain coating processes such as conversion coating(s), electrochemical machining, color metallography, and titanium/niobium jewelry. I’d think that corrosion may be defined as follows:
“Corrosion results from environmental effects on materials that produce undesirable deterioration or intended property modification.”
A definition for a word often evolves with time resulting from social and technological changes. The question is: Do current corrosion definitions reflect wholly what corrosion is? I think not. I certainly don’t see corrosion as being totally negative.
Corrosion is the good, the bad and the ugly. The good part is in the minority with plenty of examples. It should be incorporated into the definition, nevertheless.
True, we cannot stop corrosion. Corrosion can still be desirable in many ways before reaching zero life expectancy. It can be productive such as the hydriding & dehydriding process in making metal powders. It can be sophisticated like the use of photomasking techniques in forming complicated patterns. It can be beautiful, e.g., architectural titanium is being used in many distinctive buildings.
Often, it takes corrosion to mitigate corrosion.”
I totally agree that things should be kept as simple as possible. The proposed definition is simpler than most definitions and, yet, more wholly.
“Corrosion results from environmental effects on materials that produce undesirable deterioration or intended property modification.”
Similarly, corrosive can be defined as:
“Corrosive is an environment that produces undesirable deterioration or intended property modification in materials.”
Rudy Hausler: Professor Dr. Guenter Schmitt (Emeritus Technical University Iserlohn, Germany) quotes ISO 8044 as follows: “Corrosion is the reaction of a material with its environment, which occurs with a measurable change of the material and/or the environment. Such reaction can lead to corrosion damage of the material and/or the environment”. He points out (…) that any natural or man-made material can corrode according to this definition. Furthermore, the term “destructive” in connection with corrosion is too confining because it infers the notion of failure. Corrosion can occur without necessarily leading to failure.
We should, I think, also be cognizant of the fact that as technology evolves and understanding along with it, definition my change.
Tom Cox: I have no trouble going along -continuing with Dr. Mars Fontana- when I started in this field in the late’50’s he was in the top tier. My work took me into the HTHP (Author’s note: HPHT refers to high pressure and high temperature oil and gas operations, see API 17TR8 Technical Report for more information) deterioration effect on steels in the oil and gas drilling including the acid gases and not to forget the “real” culprit -PPB (parts per billion) of dissolved oxygen in the aqueous fluids- the 4 ppm dissolved oxygen in some seawaters was enough to give real problems at BHT (bottom hole temperatures) as low as 300 degrees and was the basis for some of my basic research in this area.
Abdul Rehman Noor: Corrosion is a reversion of metal to its natural oxidize state, it occurs by chemical or electrochemical reaction depending upon the environment.
Roberto Giorgini: In the context of Corrosion Science : “(Corrosion is) The reaction of a solid with its environment”.
In the context of Corrosion Engineering : “(Corrosion is) The reaction of a metal (or (a) material) with its environment, with (the) consequent deterioration in properties of the metal (or material)”.
Gurudas Saha: “Corrosion is the unintentional deterioration of materials by reaction with the environment.”
Hadi Moayed: “Corrosion is a phenomenon of increase in metallic element valance (Author’s note: oxidation number) leading to (the) deterioration (of) its properties”
Professor V. S. Raja: I think the term “Corrosion” is contextual. So, use of the term destruction to define corrosion is very desirable and appropriate. If taken out of context, corrosion could mean electrochemistry for some, metallurgy for some other and design for mechanical engineers etc.
The term passivity in reference metals is (antithesis) of corrosion that born out of corrosion. So, the definitions must be simple and unambiguous and serve the intended purpose (context) and is obviously different from summary and the later can elaborate on many associated phenomena.
Use of the term destruction to define corrosion is very desirable and appropriate”
Ilker Kasikci: After reading the dictionary definitions and handbook definitions that inserted in the article;
Putting the word “erosion” instead of corrosion, I guess, helps (as further) clarification.
Consider the erosion of the soil by the wind. It mentions a physical phenomena.
When you use the word, corrosion, I simply understand that it is a chemical (of course electrochemical) phenomena, and mostly considered for metals and today for semi-conductors (Author’s Note: according to the ASTM/NACE G193 standard, any type of material, not only metals and semiconductors, but polymers, ceramics, and composites corrode).
Yes corrosion is (a) “destructive” process and that is why (terms such as) “protection”, (e.g.) cathodic protection, exist.
Instead of splitting the term corrosion into the good, (the) bad and (the) ugly, trying to understand it as a whole will be more helpful.
Professor V.S. Raja on Ilker Kasikci’s comments: I have been pondering over the inclusion of “erosion” to define corrosion as suggested by Ilker Kasikci. In my view only (the) deterioration for which (a) chemical (Author’s note: or electrochemical) reaction is the cause, need to be (referred to) as corrosion. Materials failures/destruction/thinning occurs be several means such heat, wear, tensile, impact, fatigue and radiation by various rays, to give a few examples, where chemical environments need not aid the failure and they cannot be included in corrosion.
The above failures can be considered to be due to corrosion, once corrosion (chemical –Author’s Note: or electrochemical- reaction; the reactants could be solid, gas or liquid) assist them in some way. So I would tend to different pure erosion from erosion corrosion. This I do it because the preventive measures, mechanisms of failures do differ.
Maryam Heidari Adl: material destruction (that) happens gradually by chemical reaction of the material (with) its environment. We can not stop it but it can be controlled.
