RoHS components in a Leaded process

Hi there, I have a question about using RoHS components on leaded assemblies.

Are there any known issues with different RoHS end cap plating’s going through a leaded process?
We recently had issues with a Yageo cap part # CC0603KRX7R9BB104, during reflow solder would flow up over the end caps onto the body of the capacitor, we solved the problem by switching to the Samsung version of the same cap which we had in stock at the time.
The end terminations of each cap are plated differently the Yageo caps are very course and grainy (tin) as opposed to the Samsung caps which are smooth and shiny (nickel tin), we have had no issues with the Yageo cap on RoHS assemblies.

Hi welcome to tech forum. Most times the leaded process is a lower temperature rating than the rohs compliant parts are rated for. However, many of the rohs parts are tin plated and can work well with that temp. Some of the Lead-Free component plated RoHS components have a SAC alloy for a lead coating and could be an issue. The 60/40 alloy will not be hot enough to melt the SAC alloy to create a sound joint. You would also need to check the processing times. Retinning the components might be something you could consider to make the components more compatible with the low melt 60/40 alloys being used to create the solder joints. Glenda

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