tungsten

I think they make Tungsten electrodes for TIG welders.. which are sorta electric. McMaster-C says I can even buy some that are Thoriated. Conflict and radioactive! I've always wanted to buy (hold) a big piece of Tungsten, just to get the heft of it.

George H.

In addition to the tungsten in the torch , Tig welders may also have tungsten electrodes in the spark gap of the high frequency generator.

Dan

- High power transmitter tubes (thoriated tungsten cathodes)

- Rotating arc electrodes in (really) old mechanically operated EMC test generators for ANSI C37.90 "damped oscillatory wave" testing

- Welding electrodes

- Field emission electrodes (such as in electron microscopes)

- X-ray "targets" (x-ray tube anodes)

- And apparently a large fraction of integrated circuits of all sorts (see

Regards Dimitrij

P.S. Does this "conflict minerals" stuff have a "de minimis" clause or are you supposed to list any fraction-nanogram flying around somewhere?

Yeah, twice as dense as lead. They are used in cannon shells, really spikes, to blast tanks.

But I only care about electronic components, things that we might ship to that customer.

A customer recently asked me for REACH and FMD CoCs. I looked them up and decided I couldn't/wouldn't do it so I told them "no". They placed the order anyway.

Never used it but looks like what you need in principle. Tungsten isn't the only one.

Don't coil up your welding cable and try to use high frequency on your welder. It doesn't work well. That was the first time I realized they used spark gaps in HF welders. I wasn't welding but found it interesting. Mikek

My son and DIL's wedding rings are Tungsten. It is dense stuff.

Lots of work like RoHS, same bit.

Cheers

Tungsten's thermal coefficient of expansion seems to be close match to boro silicate glass, so it does tend to show up in glass-to-metal seals feeding current into all sorts of vacuum- and gas-filled tubes.

The only vacuum tubes that you might be using are vacuum photodiodes and ph otomultiplier tubes. Arc lamps tend to use tungsten electrodes, but silica glass envelopes - if I ever knew about the glass to metal seals that got th e current to the electrodes, I've long since forgotten.

Get it gold plated...

Point contact diodes, perhaps? I believe I heard the whisker is.

Tim

Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website:

Do you know of any electronic components that contain tungsten? Aside from incandescent lamps of course.

We have a customer that is all worked up over "conflict minerals."

That's where the name comes from: 'tung sten' is 'heavy stone' in Swedish.

Tungsten's thermal coefficient of expansion seems to be close match to borosilicate glass, so it does tend to show up in glass-to-metal seals feeding current into all sorts of vacuum- and gas-filled tubes.

The only vacuum tubes that you might be using are vacuum photodiodes and photomultiplier tubes. Arc lamps tend to use tungsten electrodes, but silica glass envelopes - if I ever knew about the glass to metal seals that got the current to the electrodes, I've long since forgotten.

The 'glass' (fused silica/quartz) to metal seals in arc tubes for HID lamps typically use molybdenum foil.

JB

As others have mentioned, many ICs. They use tungsten plugs to fill the via holes between metal layers. I expect that there are some proceses that don't use it (probably some very old ones) but that would be fairly restrictive. I wonder if TSMC offers the process option to specify hand-stroked ethically sourced organic tungsten, along with your high-resistivity poly resistors and thick top metal for inductors.

iirc tungsten slabs are also sometimes put under large silicon die that need heatsinking, where thermal mismatch between the large die and copper would stress the die. Tungsten offers a reasonable CTE match to the silicon and has decent thermal conductivity.

Tungsten & W nitride is apparently used as a barrier in many ICs.

TI's policy:

--sp

Next time instead of outright ...no..

give them an option of paying extra, and set the fee high as you wish, if they want them badly enough at least you can make some easy money.

The world needs to understand how much bureaucratic nonsense costs.

Mark

They better hope their ring fingers never swell up.

Cheers

Phil Hobbs

Tungsten also bonds very well to the glass, if you touch it with the torch till it turns green before collapsing the glass around it.

Cheers

Phil Hobbs