Presentation on theme: "What is plasma? Plasma is an ionized gas comprising molecules,atoms, ions ( in their ground or excited states) electrons and photons. It is electrically."— Presentation transcript:
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.
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.