Dear All
Recently, I use deposit copper thin film on titanium and glasses via thermal vapor deposition under vacuum. I intend to use it as an electrode to do electrochemistry in
alkaline electrolyte (KOH or NaOH), which has been done by many groups. However, I discover that copper somehow "dissolves" in 1 M NaOH. It looks like there is some kind of reactions happening between copper metal and NaOH. I tried to look it up online and found that there should no reaction between copper metal and NaOH, which is very odd to me.
Did anyone observe this before? Are there any reactions between copper metal and NaOH?
Thank you!
An interesting question . Usually , copper displays no rection with lower concentration of sodium hydroxide , unless temperature is high to facilitate faster reaction ...
Dear Wei Jyun Wang corrosion of metallic copper does indeed take place in the presence of sodium hydroxide solutions. Please find attached an article in which this process is described. The paper is freely available on the internet.
Thank you so much, Frank! I did some experiment and discovered the corrosion of copper will occur at the gas (air)-liquid interface.
Dear Wei Jyun Wang ,
the specific (thin film) Cu-corrosion experiments, you did, depend, strongly, on some different factors (the rate of Cu-metal corrosion, the active[1-3] path of dissolution, etc.) as well as different (thin film) Cu/substrate morphologies. So, which one[4] of the very different cases[3,4] (case#2 ?) did you test ?
1. Causes of Stress Corrosion Cracking (SCC) https://corrosion-doctors.org/Forms-SCC/scc-causes.htm https://corrosion-doctors.org/InternetResources/NPL.htm#Stress%20-%20complete
2. Stress Corrosion Cracking Mechanism https://corrosion-doctors.org/Forms-SCC/scc-mechanism.htm
3. Galvanic Corrosion https://galvanizeit.org/corrosion/corrosion-process/galvanic-corrosion
4. A note for some (very different) Cu-corrosion cases (list):
1. (thin film) Cu/Ti [+ galvanic corrosion#1][3]
2. (thin film) Cu/Ti-O/Ti [+ galvanic corrosion#2][3]
3. (thin film) Cu/glass(es)
4. (bulk) Cu.
Dear Wei Jyun Wang , your observation that copper corrosion occurs at the gas-liquid interface clearly shows that air oxidation to Cu2+ plays a major role in this progress.
Indeed, copper can corrode in such system (if it does non include any other impurities) due to interaction with oxygen as oxidant. But are you sure that the products are Cu2+ ions? May be these can be also hydroxide of Cu+
Dear Wei Jyun Wang referring to the answer by Alexander Pud: What did you observe? Did the copper surface turn black, or did a green or blus coloration in the solution?
Dear all, the attached file gives a systematic study of this reaction with the multitudes of potentials. My Regards
- Badges
- Science topic