[TenTec] electron flow vs. current flow

[Stuart Rohre]

Your friend is talking about "conventional current" or hole flow when the
positive to negative direction is mentioned, and electron current flow when
negative to positive is considered.  The stripping off of electrons leaving
a hole in the atom's orbit of electrons, and thus an apparent hole flow in
the opposite direction to electron flow,  is what cathodic protection is all
about.  A metal that more easily corrodes is used to be the sacrificial
electrode to keep the steel pipe from corroding. It has to be electrically
connected in a circuit with the pipe.  Such a metal is magnesium, a more
"active" electrochemically, metal than steel.  We do the same by bolting
magnesium onto aluminum sonar housings, or onto steel ship hulls.  The
magnesium is given up over time, and must be replaced, the aluminum gets a
little surface oxidation, but does not pit and corrode away.  Corrosion is
the breaking down of the material when the electron balance is destroyed in
it.  Oxygen and other active elements or compounds hasten the process in
metals.

73, Stuart K5KVH



--
FAQ on WWW:               http://www.contesting.com/FAQ/tentec
Submissions:              tentec@contesting.com
Administrative requests:  tentec-REQUEST@contesting.com
Problems:                 owner-tentec@contesting.com