People connected with R&D in corrosion

• Ragavendraprabu Govindaraju

  Corrosion inhibitors for fire water system materials

  What is meant by fire water system materials?

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    Antonio DiNunno replied

    I just went off of my knowledge of construction protocols, thin tube systems are usually copper, larger tubes such as hydrant feeds are going to be iron based, (ductile iron?) and or coated.

    23 days ago
• sanaulla pathapalya Fakrudeen

  Among AA6061 and AA6063 alloys, which alloy is highly corrosive in 1M HCl?

  What are approximate corrosion potentials(Ecor) and corrosion current(Icor)? Literature survey says aa6061 is highly corrosive due to presence of Fe, Cu and SI confirm
• Gopal Anugula

  I would like to know what are the factors effect the rest potential(ocp) while estimating the Impedance/Resistance/Corrosion rate?

  My rest potential is fluctuating rapidly in alkalin media for coated aluminum material for Impedance measurement, though I could not able measure the Impedance.So anyone please suggest me what canMy rest potential is fluctuating rapidly in alkalin media for coated aluminum material for Impedance measurement, though I could not able measure the Impedance.So anyone please suggest me what can be done to attain proper mesurement.

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    sanaulla pathapalya Fakrudeen replied

    Among AA6061 & AA6063 alloy which alloy is highly corrosive in presence of 1M HCl.

    Apr 15, 2012
• Mahmoud Reda

  Feedback about the following mechanism responsible for the effect of Chromium Conversion Coatings (CCC)

  Chromate conversion coatings (CCC) are commonly used for protecting Al alloys because they are very effective against localized corrosion and promoting paint adhesion. However, because of the highChromate conversion coatings (CCC) are commonly used for protecting Al alloys because they are very effective against localized corrosion and promoting paint adhesion. However, because of the high toxicity and carcinogenic effect of Cr (VI), which is the main component in CCC processing chemistry, has resulted in increasingly strict regulations its usage and waste disposal. Efforts have been made to develop environmentally friendly, alternative coating systems, but so far few have been able to match the performance of CCCs. Arguably, according to Buchheit and co-workers [1], this is due to the lack of complete understanding of CCC formation and corrosion protection mechanism. Furthermore, according to Buchheit and co-workers [1], the structure and chemical composition of CCCs has been the subject of numerous studies. The findings of these studies show that CCCs to be a mixture of chromium oxides. Chromium is present in CCC as both Cr (III) and Cr (VI), with Cr (VI) predominantly present in the outer layer. Several mechanisms have been proposed to explain the excellent corrosion protection provided by CCCs. Among them, according to Buchheit and co-workers [1], the barrier layer protection mechanism, the bipolar membrane mechanism and the active corrosion protection mechanism. In this work a new mechanism is proposed which is based on the formation of a mixed valence compounds (Redox couple Cr (III)/ Cr (VI)) according to Robin-Day classification II/III [2]. This mechanism can easily explain the self-healing effect of the CCC which is due to the inter-valence charge transfer (IVCT an intrinsic property of mixed valence compounds) induced by the parasitic electron generated from localized corrosion. This IVCT can be detected by Raman Spectroscopy. [1] Zhang , B. Hurley and R. G. Buchheit, J. Electrochem. Soc., 149, 8, B357-B365 (2002) [2] P. Day, N.S. Nush and R.J. Clark, Mixed Valence : Origin and Developments, Phil. Trans. Roy. Soc. A, 366, 5-14, (2008)

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    Gopal Anugula replied

    Good effort .

    Apr 12, 2012
• Naglaa Sadik

  What are the effects of crystal defects on corrosion?

  What is the effect of point defect and line defect and plane defect on occurance of corrosion?

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  • 
    Mahmoud Reda replied

    It depend on how do you define crystal defects. Most corrosion products at surface are amorphous.

    Apr 10, 2012
• Naglaa Sadik

  What about corrosion in space?? And what are the factors which affect on it's occurance??

  I WANT to know the reasons for corrosion occurance in the space?
• Gopal Anugula

  Comparison of Corrosion rates and their relative rating.

  Please anyone suggest me that how to give the relative rating based on corrosion rates.If anyone has literature/links/calculations/Ideas please let me know...

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    Shanmugam ss replied

    why ur not trying... polarization and impedance studies for that.. its is give better results related about corrosion rate...

    Feb 20, 2012
• Hari Kumar S.

  I would like to know the application of DRS in corrosion studies.

  Can anyone suggest me suitable materials related to this
• Aqil khoda bakhsh

  Hi ppl, does any one know about corrosion on air cooler tubes? Its mechanism and factors that affect on it and etc

  Please tell me about corrosion of tubes of air coolers pitting type

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    Antonio DiNunno replied

    I've done quite a few studies on cooler tubes and the cause of corrosion can vary based on the variables. Copper has its sensitives, as does stainless steel, as does aluminum. One of the moreI've done quite a few studies on cooler tubes and the cause of corrosion can vary based on the variables. Copper has its sensitives, as does stainless steel, as does aluminum. One of the more interesting pitting events I've seen is formicary corrosion or "ants nest corrosion" http://digital.csic.es/bitstream/10261/2120/1/33.pdf I've also had cases that looked like formicary corrosion but turned out to be due to sulfates and chlorides, others that were due to stray current, others due to erosion. Your profile says you are involved in gas (natural, petrol?) refining, I'd be on the look out for carboxylic acids if from an oil source, inorganic acids and salts if from shale. I'd be very interested in doing an investigation!

    Jan 25, 2012