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Cleaning Indium Thermal Interface Material (TIM) Preforms

Here is a question that was posted and answered on our website back in 2006, I think it is still quite relevant:

Question: “Why does your Application Note for cleaning of indium ribbon for thermal interface recommend a mild (5-10%) HCl acid solution, yet [the] SDS for Indalloy #4 (100%) says to avoid contact with acid? My past indirect experience with indium usage indicated some cleaning procedure of the oxides was necessary to achieve good thermal contact resistance.”

Answer: “Thanks for contacting the Indium Corporation with your request. If the indium ribbon is stored and handled (stored unopened in an argon or nitrogen pack – placed in a dry box) properly and it solders well in your process, this procedure should not be necessary. When following this procedure, the HCl solution should be applied to the indium metal to clean it thoroughly, and then dried with nitrogen.

If you want to know more about metal thermal interface materials (TIMs) (handling, preparation, or process parameters), send an email to our global technical team at: They are ready to answer your question!