Somewhat OT: Long term design

[JosephKK]

This is where I wonder about difusion. Will those doping atoms stay put
over those sorts of time scales, or would we end up with a piece of
silicon pretty much equally doped throughout with both doping materials?

Sylvia.

They will stay put pretty well. Solid solubility at normal terrestrial
surface temperatures is mighty low. Micron per hour diffusion requires
about 2000K. And the mobility does follow the e^kt Arrhenious
relationship.

 

[Nico Coesel]

Tantalums are fine as long as their peak current (ie, dV/dT) is
limited. Of course, that makes them useless for most places you'd like
to use them.

Lets say that I found too many defective tantalums in broken
equipment. When it comes to capacitors: electrolytics come first,
tantalums next. Besides that, a lot of rain forrest is cut to get the
tantalum.

 

[Uwe Hercksen]

You could cheat and store the gear in Antartica. Most degradation
mechanisms follow the Arrhenius relationship.

Hello,

you forgot the bad effect of temperature cycles at low temperatures
between -60 and -10 °C. Low and constant temperatures would be better.

Bye

 

[Uwe Hercksen]

Tin whiskers.

Hello,

there is another problem with tin at low temperatures, it may transform
into another modification, the solid metal will be a powder then. In
german we call it Zinnpest or tin-plague. It has destroyed some organ
pipes in churches during a very cold winter. It may be avoided by using
a proper alloy of tin.

Bye

 

[Uwe Hercksen]

It's all about maintenance. Wonder how often the bellows had to be
replaced/rebuilt? Probably even some pipes?

Hello,

not only the pipes and bellows, but also the keyboards and the valves
cotrolling the air to the pipes.

Bye

 

[Uwe Hercksen]

Aluminums fail by drying out, through water vapor leakage through the
rubber seals. That's a wearout mechanism.

Hello,

rubber often does not stand for many decades, it loses flexiblity and
goes hard and brittle developing cracks.

Bye

 

[JosephKK]

Hello,

there is another problem with tin at low temperatures, it may transform
into another modification, the solid metal will be a powder then. In
german we call it Zinnpest or tin-plague. It has destroyed some organ
pipes in churches during a very cold winter. It may be avoided by using
a proper alloy of tin.

Bye

I have also heard of it being a problem with the buttons of early 1900s
Russian military uniforms in very cold climates.

 

[David Lesher]

Jim Thompson schrieb:

not only the pipes and bellows, but also the keyboards and the valves
cotrolling the air to the pipes.

and the organist....