Hello Ashish Thakur ,

Even the premise of your question is highly contested in the sense that not everyone agrees that noble metals do not oxidize. For a historical treatment of this question, please, see the following document on my RG page: Research Passivation Layer on Noble Metals

Regards,

Tom Cuff

Dear Thomas,

Question is interesting. Question is why they do not rust in immersion condition?

In immersion condition, since nobel metal does not oxidise and hence energy transfer through the Nernst electrochemical formula (e- E0- kT/ne (ln Red/Ox)=RT/zF(ln Red/Ox), cathode(red) and anode(oxi) becomes equivalent hence Ln 1 =0(in exponential form), so Ecell becomes equal to E0, cahodic and anodic level have equal, hence no corrosion occurs. Consequently no rust may occur.There is no adding oxygen.

Come to physics principle, electron transfer to migrate at one level cathode to anode is zero. try with cyclic polarization curve, Tafel plot beta a, its almost show in impendence is zero level. So mobility of electron required to oxidize it almost zero. Hence, there is no rust occur.So, no new nucleation or growth occur. At the molecular level there is no segregation of electron from element occur at nucleus. No grain boundary will form due to hydrogen impermeability filtration from liquid.

Ashish

Dear Thomas,

U r true and I am agreed. I appreciate your answer.

Question is interesting. Question is why they do not rust in immersion condition?

In immersion condition, since nobel metal does not oxidise and hence energy transfer through the Nernst electrochemical formula (e- E0- kT/ne (ln Red/Ox)=RT/zF(ln Red/Ox), cathode(red) and anode(oxi) becomes equivalent hence Ln 1 =0(in exponential form), so Ecell becomes equal to E0, cahodic and anodic level have equal, hence no corrosion occurs. Consequently no rust may occur.There is no adding oxygen.

Physics

Come to physics principle, electron transfer to migrate at one level cathode to anode is zero. try with cyclic polarization curve, Tafel plot beta a, its almost show in impendence is zero level. So mobility of electron required to oxidize it almost zero. Hence, there is no rust occur.So, no new nucleation or growth occur. At the molecular level there is no segregation of electron from element occur at nucleus. No grain boundary will form due to hydrogen impermeability filtration from liquid.

Ashish

Dear Thomas,

U r true and I am agreed. I appreciate your answer.

Question is interesting. Question is why they do not rust in immersion condition?

In immersion condition, since nobel metal does not oxidise and hence energy transfer through the Nernst electrochemical formula (e- E0- kT/ne (ln Red/Ox)=RT/zF(ln Red/Ox), cathode(red) and anode(oxi) becomes equivalent hence Ln 1 =0(in exponential form), so Ecell becomes equal to E0, cahodic and anodic level have equal, hence no corrosion occurs. Consequently no rust may occur.There is no adding oxygen.

Physics

Come to physics principle, electron transfer to migrate at one level cathode to anode is zero. try with cyclic polarization curve, Tafel plot beta a, its almost show in impendence is zero level. So mobility of electron required to oxidize it almost zero. Hence, there is no rust occur.So, no new nucleation or growth occur. At the molecular level there is no segregation of electron from element occur at nucleus. No grain boundary will form due to hydrogen impermeability filtration from liquid.

Ashish

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