Spray Pyrolysis Lab

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Solution growth deposition This technique consists essentially of inserting the substrate into a solution containing hydrolysable metal compounds and pulling it out at a constant speed into an atmosphere containing water vapour. In this atmosphere, hydrolysis and condensation takes place. Finally the films are hardened by a high temperature cycle to form transparent metal oxides. Any hydrolysable compound including halides or nitrates but preferably metallo-organics are suitable for this process. The important control parameters are the viscosity of the solution, the pulling speed and the firing temperature. The rate of heating also needs to be controlled to avoid cracking of the films. This technique has been used commercially …show more content…
2.5.2 Spray pyrolysis experimental setup The schematic diagram of the spray pyrolysis experimental that is built in our laboratory and employed to prepare the films under study is shown in below Figure2.5. The reaction involved in this technique is the thermal decomposition of the solution that falls on the preheated substrate. The desired chemical solution that is sprayed, by a glass spray gun, onto the substrate kept on hot plate is decomposes to yield thin film. The setup consist the following components.
Spray gun A glass made double nozzle spray gun, which is shown in Figure is used for getting the spray action. The spray gun is a coaxial assembly of quartz tube and capillary having inner diameter of 0.07mm. Both the capillary and glass tube are tapered at one end to minimize the inner diameter to a maximum extent possible and thus forming a nozzle. At the other end the capillary is made to slightly lengthier than that of quartz tube and the tube is fused with the outer surface of capillary. The capillary is used as the inlet for solution and an inlet is made on quartz tube for passing carrier gas (filtered compressed air). Hence if the carrier gas is allowed to pass through the tube it will attain more pressure due to the tapered end and it results in spraying the solution droplets that comes out of

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