Hi James baldengineer

Well for me:

For many decades I have deliberately not used low-temperature solder because that has several problems.

First:

the alloy. If this is not adapted to the material of the component connections, galvanic elements are created that set the oxidation in motion.

The component and the soldering point will be destroyed. "Cold soldering point" - is basically an outgassing within the soldering point, where the connection is oxidized.

Second:

When there are power components on the circuit board and they get hot during operation.

"Warm solder moves", it comes to "flow", so that the soldering point also changes here.

In particular, if there is shaking during operation, this "cold soldering point" occurs again - broken solder.

You can't see it on the outside, but over time the components come loose and the device no longer works.

In the service company I had to repair 1000s of such broken solder joints.

They are very difficult to find because most of the time you can't see them from the outside.

Have you a microscope because that defects are often very small?

Components with a corresponding temperature range. Usually this is up to + 85 ° C.

But there are components that can be used up to 125, 150 ° C. So it is very close to the melting point of the solder.

Accordingly - what happens at minus temperatures? Especially bismuth. Is something crystallizing there?

-> Whiskers. They are not only created in the component, but also at the soldering point.

Third:

the contact resistance from one element to the next.

Wire tracks - solder - component pin.

This then has to be really checked with the appropriate measuring devices. e.g. - RF applications, i.e. the clock signal, the transmission signal in high-speed applications, etc.

Every resistor is a junction point for signal edges, generating signal losses. - Signal integrity.

So it is not easy to use a soldering method "just like that", actually, as everywhere in development, to use "any" methods.

Bismuth - interesting. I have always avoided solders with bismuth. This element has been banned from use all along, for decades. Now it is being used again.

Namely, it has properties that cannot be used everywhere. It is in many ways contrary to the properties of other elements.

Well, then I'll have to check again ...

Bismuth - Wikipedia

Here was what spoken about radiation.... hmmm....

Radiation - a no-go! in the electronics device.

It's good that you mentioned that here in Element14.

Best Regards

Gerald

Gerald, thank you for the reply.

These are exactly the kind of points I was looking to consider. Especially the minus temperatures. I had not given that aspect any thought.

Gerald, thank you for the reply.

These are exactly the kind of points I was looking to consider. Especially the minus temperatures. I had not given that aspect any thought.