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THE PROJECT
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Plasma
refers to the forth condition of the matter. Plasma, that is,
is a partially or totally ionized gas, thus, that particular
gas condition in which neutral molecules, positive ions and
free electrons are all present at the same time. In this case,
plasma means low energy content: higher or lower energy content
defines a "cold" plasma compared to a "hot"
one.
Cold plasma used for the phases of pre-treatment, cleaning and
washing of a substrate of any type of material is obtained at
low pressure (vacuum). This condition allows reactions to take
place in a temperature range of 20 to 30 °C inclusive while
in conditions of atmospheric pressure these are possible only
at temperatures of hundreds of degrees. In fact, despite the
low temperature of the gas, the temperature of the electrons
is very high (from 20 to 50.000 K) due to the length of the
free run of the particles.
This makes the treatment of organic material possible (for example
plastic material), which do
not tolerate high thermic loads. Plasma of a gas is by nature
unstable and can be istinguished by its strong reactivity in
particular conditions of pressure and when there are very intense
electric fields.
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The applied electric field must supply sufficient energy to
the particles which permit a general
ionization of the gas due to reciprocal collision. The gas flow
dosage, the process pressure and the intensity of the electric
field must balance the ionizing forces and the natural tendency
of ionization decay.
The nature of a plasma varies a lot according to the type of
gas, or to the mixture of different
gases, pressure of gas/gases, form of volume which confines
the plasma itself, the type of electric field which supports
and maintains the plasma. The plasma of particular gases, among
which oxygen is always present, allows oxidation to develop
at a low temperature when it comes into contact with the surfaces
to be treated.
That is, the formation of functional groups on the surfaces
themselves which permit optimal
conditions for total cleaning to be obtained. |
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KOLZER via Francia, 4 - 20093 Cologno Monzese
(MI) Italy
tel.: +39 02 25 43 193 fax: +39 02 27 305 586 e-mail: info@kolzer.it
credits
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