Atmospheric Effect on Dendrite Growth

[WAYNEL]

I am trying to calculate if the atmosphere has an affect on the growth
of dendrites, e.g. copper. Eliminating the atmosphere and growing
dendrites in a vacuum may prove to be difficult to run, as the
electrolyte will outgas and thus evaporate.
However, if a test was constructed using Argon or any other inert gas
would one notice an effect?
Consider another test. Rather than using an inert gas, used CO2, could
this effect the growth of a dendrite.
Are there papers on the atmospheric effect on dendrite growths?
Can anyone propose any potential effects the atmosphere may have?
Or is the electrolyte the "dendrite's atmosphere" and this
vehicle may pick up atmospheric contaminates that could produces
various species?


Cheers

WayneL

 

[Ian Stirling]

I am trying to calculate if the atmosphere has an affect on the growth
of dendrites, e.g. copper. Eliminating the atmosphere and growing
dendrites in a vacuum may prove to be difficult to run, as the
electrolyte will outgas and thus evaporate.
However, if a test was constructed using Argon or any other inert gas
would one notice an effect?

Well, obviously, the atmosphere can have no direct affect on dendrite
growth, as it doesn't touch the dendrite growth region.
Some gasses can dissolve in electrolytes, if not sealed, and
may have an effect.

 

[jacques jedwab]

I am trying to calculate if the atmosphere has an affect on the growth
of dendrites, e.g. copper. Eliminating the atmosphere and growing
dendrites in a vacuum may prove to be difficult to run, as the
electrolyte will outgas and thus evaporate.
However, if a test was constructed using Argon or any other inert gas
would one notice an effect?
Consider another test. Rather than using an inert gas, used CO2, could
this effect the growth of a dendrite.
Are there papers on the atmospheric effect on dendrite growths?
Can anyone propose any potential effects the atmosphere may have?
Or is the electrolyte the "dendrite's atmosphere" and this
vehicle may pick up atmospheric contaminates that could produces
various species?


Cheers

WayneL

Most theories of dendrite growth attribute this habit to differential
concentrations of impurities on certain crystal faces, edges, corners,
etc.
But these theories were devised for metal melts.

J.J.

 

[Bill Janssen]

Most theories of dendrite growth attribute this habit to differential
concentrations of impurities on certain crystal faces, edges, corners,
etc.
But these theories were devised for metal melts.

J.J.

Bell Labs may have published info on dendrites as the telephone
companies had trouble
with dendrites in sealed crystal filters. One of the repair practices
was to put a "megger" on
selected connections and burn the dendrite clear. I seem to remember
Bell Labs publishing
something on the problem. The filter problem (I think) involved Tin. The
problems
I remember were in the 1950's time frame.

Bill K7NOM

 

[doug dwyer]

jacques jedwab wrote:


Most theories of dendrite growth attribute this habit to differential
concentrations of impurities on certain crystal faces, edges, corners,
etc.
But these theories were devised for metal melts.

J.J.
Bell Labs may have published info on dendrites as the telephone
companies  had trouble
with dendrites in sealed crystal filters. One of the repair practices was to
put a "megger" on
selected connections and burn the dendrite clear. I seem to remember
Bell Labs publishing
something on the problem. The filter problem (I think) involved Tin. The
problems
I remember were in the 1950's time frame.

Bill K7NOM

Marconi Co uk had problems with tin whisker growth on electro tinned
brass parts in crystal filters.
Grew 10 to20mm whiskers of tin in an inert nitrogen atmosphere within a
year or so.
Shorted out the variable caps mostly.
When the tin plating was oil immersed to re-?flow after plating the
problem went away.
Relevant to replacing lead with tin for solder process.
At the time it was said that the plating process resulted in stress in
the tin lattice.

 

[WAYNEL]

Thanks, but tin whisker as form by a different phenomenon. They are
not dendrites.

Cheers

see http://www.empf.org/empfasis/sept03/tinwisk1.htm


WayneL

 

[Roy Lewallen]

Marconi Co uk had problems with tin whisker growth on electro tinned
brass parts in crystal filters.
Grew 10 to20mm whiskers of tin in an inert nitrogen atmosphere within a
year or so.
Shorted out the variable caps mostly.
When the tin plating was oil immersed to re-?flow after plating the
problem went away.
Relevant to replacing lead with tin for solder process.
At the time it was said that the plating process resulted in stress in
the tin lattice.

Thick-film hybrid circuits often used silver for the circuit traces, and
dendrite growth between traces which had a DC voltage difference was a
serious problem. The solution was to alloy the silver with palladium,
which either eliminated or greatly reduced the growth. I'm not enough of
a chemist to know why, but I'm sure anyone interested should be able to
find quite a body of information in publications relating to hybrid
circuits. The IEEE has a professional group which deals with hybrid
circuits, and I'm sure the associated Transactions journal has a lot
about this.

Roy Lewallen

 

[Dieter Britz]

I am trying to calculate if the atmosphere has an affect on the growth
of dendrites, e.g. copper. Eliminating the atmosphere and growing
dendrites in a vacuum may prove to be difficult to run, as the
electrolyte will outgas and thus evaporate.
However, if a test was constructed using Argon or any other inert gas
would one notice an effect?
Consider another test. Rather than using an inert gas, used CO2, could
this effect the growth of a dendrite.
Are there papers on the atmospheric effect on dendrite growths?
Can anyone propose any potential effects the atmosphere may have?
Or is the electrolyte the "dendrite's atmosphere" and this
vehicle may pick up atmospheric contaminates that could produces
various species?

Oxygen would of course be reduced along with Cu++, and it's
hard to say whether this could affect dendrite growth. My guess
is not, but I can't be sure. Since you are experimenting with it,
try it out. Certainly I would be pretty confident that an Ar
atmosphere would not affect dendrites, as Ar is inert, and it is
hard to see how the small ampount that would dissolve in the
electrolyte could have any effect at all. CO2 - well, hard to say.
It would affect the pH, and that itself might cause a change.

 

[Martin Riddle]

Eagle Pitcher (the battery company) had some problems with their sealed batteries and dendrite growth when dischaged and left un-used. I recall a topic on wiskers, but I dont know if its the same chemical process.

Cheers

jacques jedwab wrote:

I am trying to calculate if the atmosphere has an affect on the growth
of dendrites, e.g. copper. Eliminating the atmosphere and growing
dendrites in a vacuum may prove to be difficult to run, as the
electrolyte will outgas and thus evaporate.
However, if a test was constructed using Argon or any other inert gas
would one notice an effect?
Consider another test. Rather than using an inert gas, used CO2, could
this effect the growth of a dendrite.
Are there papers on the atmospheric effect on dendrite growths?
Can anyone propose any potential effects the atmosphere may have?
Or is the electrolyte the "dendrite's atmosphere" and this
vehicle may pick up atmospheric contaminates that could produces
various species?


Cheers

WayneL

Most theories of dendrite growth attribute this habit to differential
concentrations of impurities on certain crystal faces, edges, corners,
etc.
But these theories were devised for metal melts.

J.J.
Bell Labs may have published info on dendrites as the telephone companies had trouble
with dendrites in sealed crystal filters. One of the repair practices was to put a "megger" on
selected connections and burn the dendrite clear. I seem to remember Bell Labs publishing
something on the problem. The filter problem (I think) involved Tin. The problems
I remember were in the 1950's time frame.

Bill K7NOM

 

[Bob Stephens]

Oxygen would of course be reduced along with Cu++, and it's
hard to say whether this could affect dendrite growth. My guess
is not, but I can't be sure. Since you are experimenting with it,
try it out. Certainly I would be pretty confident that an Ar
atmosphere would not affect dendrites, as Ar is inert, and it is
hard to see how the small ampount that would dissolve in the
electrolyte could have any effect at all. CO2 - well, hard to say.
It would affect the pH, and that itself might cause a change.

What is going on with this thread? My reader is choking on it big time.
Won't dwonload any headers after this one

Bob

 

[Al]

Back in the 70's, we had a problem with dendritic growth inside of T-03
power transistor cases. The experts at the time couldn't determine the
cause but speculated that it was due to migration of the hard die
solder. How and why was never explained. The lot of transistors was
replaced and the problem "went away."

Al