BLF Interest list for Very High Current Beryllium Copper springs Pt1(ENDED)

Further:

Zinc is a good coating to protect steel springs from corrosion (galvanising).

But as for beryllium copper, I doubt it.

Look at the electropotentials.

Beryllium is far higher than zinc. Everything higher will corrode preferentially.

So I suggest zinc will have no protective effect for a BeCu spring, just make it less solderable. Even if it can be cleanly applied.

But I think we are already agreed that zinc plate is not the way forward.

PS: I learned this stuff at school from my chemistry teacher. His demonstration was to use his gold wedding ring and a strip of zinc in some electrolyte (very strong acid, got the zinc fizzing), and measure the electropotential. We all worried that his wedding ring might dissolve. No chance.

+100

During the specification choosing process, I was thinking of a steel spring’s electrochemical properties, not a copper alloy spring. I do not know why.

Thanks a lot for the reminder.

This is why I initially asked the question here yesterday. For some reason, I was feeling something was wrong about combining copper and zinc together, because I noticed every book/Internet source that I checked never spoke about zinc plating with copper, but instead, with gold/nickel/tin/silver/nickel-tin.

I was worried I was wrong somewhere, and I was!

Thanks again guys a lot for your help.

TLDR: Nickel-tin plating it is, applied in two separate layers, nickel being above the BeCu substrate protecting it from the tin above, and allowing for good solder ability, along with sufficient softness to allow for excellent contact with the cell.

Easier to solder a bypass because you're changing an insignificant amount of spring (thermal) mass?

Nickel plated and then tin plated? How is the raw tin plating going to resist being solder heated at and above tin's melting point (232°C)? I guess it should do 0K because the soldering heating is quite momentary…

Is the employed BeCu alloy even nastier than nickel with regards to soldering?

Cheers ^:)

No.

Actually, BeCu can be more easily soldered than Nickel. The reason for a plating is to protect the BeCu from corrosion, especially when soldering. I did notice this behavior on the Carobronze springs, which are not plated.

The science behind nickel-tin plating being so good in regards to soldering is because tin alone, while being very easy to solder to, if it soldered without having something like nickel under it, it will have a tendency to form whiskers, which degrades contact resistance.

Adding nickel as a substrate to the tin allows us to solve that problem, and also granting a layer of corrosion protection.

Nickel alone has the problem of being very hard, so contact resistance is inferior to tin.

Therefore, nickel-tin is the best bet for our spring, and should have the advantage of being easy to solder to, having good contact resistance, and preventing the BeCu from oxidizing, especially on 250°C+ soldering temps.

UPDATE 6

The plating is now going to be nickel-tin.

The springs have started production.

Thank you for the update BSM!! :beer:

I’ll post some pictures of the springs when they will send them to me.

Hopefully they will looks good :slight_smile:

Well, guys, I think everybody will like this picture.

Pure BeCu C17530 springs, and nickel plated BeCu C17530 springs.

These look perfect.

:+1:

They look great BSM, thanks for the update!! :+1:

Orsm. :beer:

You can put me down for 15 big ones.

I know I’m coming in late, but if they are still available, I’d like 25 of the large, and equal interest in a similar quantity of smalls, if they get made.

We are at 1807 big springs and 1328 small springs.

We are getting close to closure for the big springs, and the threshold is 1950 big springs.

Wow, nice! So now the springs are going to be tested?

Yes of course I’m going to test the springs.

I’m going to test their mechanical properties along with their electrical properties.

:crown: :+1:

Yeah nice. I hope these are the springs that are the best of both worlds: good mechanical properties, and great electrical conductivity.

New update again.

Now all of the springs have been made, and electroplated!

They are going to ship out tomorrow, and they should come next week. I will be testing them.

I am so happy this is turning out so well.