What is plasma Plasma is an ionized gas

What is plasma? • Plasma is an ionized gas comprising molecules , atoms, ions ( in their ground or excited states) electrons and photons. It is electrically conductive since there are free electrons and ions present , and is in local electrical neutrality.

PLASMA SYNTHESIS

PLASMA SYNTHESIS • In a plasma source system, an inert gas, such as argon, flows into a chamber. • This gas carries macroscopic particles of the material from which you want to produce nanoparticles. • A high-power radio frequency signal applied to the carrier gas produces plasma, which then flows into a cooled chamber. • The ions then condense into nanoparticles. This method is often used for volume production of metallic nanoparticles.

RF PLASMA METHOD • In the synthesis of nanoparticles by RF plasma method , a plasma is generated by RF heating coils. • The starting metal is contained in a pestle and this pestle is contained in an evacuated chamber. • The metal is heated above its evaporation point by using high voltage RF coils wrapped around the evacuated chamber. • Helium gas is allowed to enter the system and this gas forms a high temperature plasma in the region of the coils. • The metal vapour nucleates on the helium gas atoms and diffuses up to a cold collector rod, where nanoparticles are collected. • Finally these nanoparticles are passivated by the introduction of appropriate gas (Oxygen)

RF PLASMA METHOD FOR VAPOUR PHASE REACTIONS • RF plasma has a larger frame or reaction volume than the DC. • Efficiency of particle production is higher. • It is able to operate without any electrode. • Enables nanoparticles to be obtained as pure as the raw material without suffering contamination from the evaporation of the electrodes. • Raw material is instantaneously evaporated in high temperature plasma frames. • The produced vapour condensed into nanoparticles by subsequent rapid cooling.

VACUUM SYNTHESIS

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