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vacuum deposition
Condensation of thin metal coatings on the cool surface of work
in vacuum.
valence
A positive number that characterizes the combining power of an element
for other elements, as measured by the number of bonds to other
atoms that one atom of the given element forms upon chemical combination:
hydrogen is assigned valence 1, and the valence is the number of
hydrogen atoms, or their equivalent, with which an atom of the given
element combines.
vapor deposition
See chemical vapor deposition, physical vapor deposition and
sputtering.
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vapor
plating
Deposition of a metal or compound on a heated surface by reduction
or decomposition of a volatile compound at a temperature below the
melting points of the deposit and the base material. The reduction
is usually accomplished by a gaseous reducing agent such as hydrogen.
The decomposition process may involve thermal dissociation or reaction
with the base material. Occasionally used to designate deposition
on cold surfaces by vacuum evaporation. See also vacuum deposition.
voids
A term generally applied to paints to describe holidays, holes,
and skips in a film. Also used to describe shrinkage in castings
and weld. |