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I have silver oxide in an ink formulation. When I apply it (in small quantities) over aluminum and heat the resulting (to evaporate the solvent), the monovalent silver oxide seems to decompose to Ag. The temperature I am evaporating the solvent is around 30-40˚C. The decomposition of Ag2O to Ag occurs at a temperature over 200˚C. However, I am aware that aluminum is a good conductor of heat, so even though the temperature was only 30-40˚C, Ag2O could have deposed because the temperature on the aluminum surface could have been around (or higher than) 200˚C.

My question is, is there a way to solve this problem. How can I still use aluminum and not worry about decomposing Ag2O to Ag when evaporating the solvent? Do I have to further reduce the temperature and is this the only solution? I tried to research this concept but couldn't find anything.

Thank you so much for your help.

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First, as you mention, $\ce{Ag2O}$ starts to decomposes from ≥200 °C. Measure the temperature of the aluminum substrate with an IR thermometer or attached thermocouple to be sure you stay well below that. You can substantially speed drying of the ink by lowering the air pressure, e.g. using an aspirator pump, perhaps eliminating need to heat the substrate.

You may also need to anodize the aluminum prior to printing to prevent chemical reaction with the $\ce{Ag2O}$ in the ink. Aluminum is much higher in the electromotive series and would rapidly replace silver in the oxide.

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  • $\begingroup$ Thank you so much for your answer. I was researching a bit and found out to switch aluminum for copper (for several other issues). Aside from the anodizing, is there anything to keep in mind with copper. Do I just worry about reducing the air pressure or can I do something else with copper. Thank you so much! $\endgroup$ – user5139637 Jul 22 '16 at 20:30
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    $\begingroup$ Copper is less reactive than aluminum, but is still more reactive than silver, so there is some chance it will displace it in the oxide... it depends on how soluble the silver oxide is, and the cleanliness of the copper. The hotter the surface and the cleaner the copper, the faster will be the displacement. Anodized aluminum might work just as well as copper, particularly if you use mild vacuum to speed evaporation. $\endgroup$ – DrMoishe Pippik Jul 22 '16 at 20:35

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