Helium Kills iPhones

So now I'm thinking what effect this would have on other silicon devices.....? Is there a point that the saturation becomes irreversible...?

I think the problem is unique to MEMS resonators. The MEMS is a cantilever device etched out of silicon and sealed up in a vacuum. Helium atoms can diffuse through the silicon into the vacuum, apparently destroying the Q of the vibrating cantilever. It would be unlikely to affect pure electronic devices.

For some reason, it takes longer to recover than to fail - it can take minutes to fail and days to recover. I suspect that when the MEMS is exposed to helium, there is a gradient in helium concentration from outside to inside. When you remove the helium in the atmosphere, there is still the helium in the silicon that has to dissipate before the helium inside can diffuse away, hence the much longer recovery time. I don't know if it would ever be irreversible, but with a healthy dose, it might well take longer than you would be willing to be without your iphone.

http://nanoscale.blogspot.com/2018/11/timekeeping-or-why-helium-can.html

GA. Graphene and graphene oxide are impermeable to helium, a gas with the smallest atoms. Graphene is truly magic.

Uncooked rice won't solve this.

That's very interesting.

I need to show my son this article. He has killed a couple iPhones in his welding shop over the last couple years. He does a lot of stainless tig welding using helium as a shielding gas. We just assumed the issue was related to the welding current and were surprised when the phones powered up a few weeks later. (They probably would have worked sooner had we tried them).

Great Question !!!!

If we considered the direction and rate of diffusion through the device case/coating as a function of partial pressure gradient could the partial pressure of the helium within the partial vacuum still be higher than the helium rarified ambient atmosphere?
Now I imagine a method by which the partial vacuum can be optimized by evacuating it in a high helium environment then moving it into the helium rarified atmosphere? The helium will diffuse through the case/coating until the partial pressures are equal. I wonder what level of vacuum could be achieved.

That's an easy one. If there is differential diffusibility, each gas behaves independently.

Diffusion in each direction across a barrier is proportional to the partial pressure of the gas on the side it's coming from. The partial pressure of helium in the atmosphere is normally 0.0005% of one atmosphere, or about 0.0005kPa. So there is virtually no helium coming back from the outside, and it is just the same as if it were a vacuum. The fact that there are lots of other gases on the outside is irrelevant if the silicon barrier is impermeable to them.

If the iPhone is in a vacuum then the iPhone owner could be suffocating. They definitely won't be getting a phone call. The walls of the vacuum chamber are likely metal so not even Bluetooth will help.

Mems oscillators are fabricated in a vacuum but they typically do not get perfectly sealed with even a partial vacuum inside unless one is making a barometer version of a mems absolute pressure detector. Many mems are designed to deliberately respond to different environmental gasses.

In a vacuum no one can hear you Ring.

nor can i hear my wife talking to her sister while i am trying to watch television..

You would not suffocate, you would asphyxiate. Ends up the same though.....

Although It has been my first language for a very long time, I'm not any authority on English, so I looked up both words in two different dictionaries. I find "suffocate" somewhat more appropriate.

If there are more helium atoms inside than outside, more will pass from inside to outside. It doesn't make any difference what other gases are present or not present.

If you have a latex balloon filled with helium, in a few days, the helium will leak out, but the balloon still remains partially inflated. While the helium was diffusing out, air (nitrogen+oxygen+argon primarily) was diffusing in. At equilibrium, the partial pressure of helium is the same inside and outside (practically zero) and the partial pressure of air is the same inside and outside.

https://www.thoughtco.com/why-do-helium-balloons-deflate-4101553

There may be some sort of getter that keeps the vacuum.

That was my thoughts on why it takes longer to recoup, it may be due to the ability of the getter to grab atoms .

Unfortunately, most getters operate by chemically combining with gases, which, of course, is impossible with helium. Some will absorb inert gases, but not permanently. Getters are often used to purify inert gases.

"A getter is a deposit of reactive material that is placed inside a vacuum system, for the purpose of completing and maintaining the vacuum. When gas molecules strike the getter material, they combine with it chemically or by absorption."

"Getters cannot react permanently with inert gases, though some getters will absorb them in a reversible fashion. Also, hydrogen is usually handled by adsorption rather than reaction."

https://en.wikipedia.org/wiki/Getter

thanks for the reply and the info!

i recall using zeolite to adsorb but further research proves only at higher pressures.

again, thanks for the correction.

Why not just a good seal? Perhaps Helium is a special case because of the physical size of the the atom?
A gas diffusing to the outside of the can is different than using "a getter" because in the diffusion process there is mass exchange; in a chemical reaction the energy state changes but the mass remains constant?

Maybe this: When I worked in the plutonium fabrication building at Argonne National Lab, the gloveboxes had a helium atmosphere at somewhat less than ambient pressure so any leaks would be into the glovebox. When we took "stuff" out of the glovebox it was inside heavy vinyl bags. After some time the bags would be tight against the "stuff" due to diffusion of the helium thru the vinyl. the He molecule was small enough to go thru the vinyl when air would not; even from a low pressure as He molecules impact the vinyl bag.

REALLY interesting! Thanks!

Interesting,... raising a lot of questions...

• Does any other Noble gases like Argon have that effect?... I posted noble gases below...
• Or from your post, is it because helium has a smaller molecular weight?...
• what about hydrogen?

I’m searching for these questions now, thought I’d post.

helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og). T

Does this mean one can use the helium from a party balloon to render an iPhone or similar cell phone inoperative? I see this as an interesting, nefarious plot twist in some fiction. Presumably this will be a long term but temporary failure so the villain doesn't have to do anything to cover their tracks.