Ryan Mitchley wrote:

I've heard that if the diaphragm "bottoms out" for any reason on
a phantom powered condenser, there is the danger of minute spot
welds forming.

I haven't attempted to verify this myself :-)

You can't "verify" it with any modern microphone, since it isn't true.
Mylar film, which has been almost universally used as the diaphragm
material in most studio condenser microphones since the 1960s, is a
very effective insulator. Even if the diaphragm hits the backplate, no
current will flow--the gold layer is on the _other_ side of the Mylar.

With old-fashioned all-metal diaphragms this could be an issue according
to some folks; they say that little pinholes can be burnt. I've never
seen this myself, though. And it has nothing directly to do with phantom
powering. The issue is whether the capsule is externally polarized or an
electret.

--best regards