Nanoscale Tin Oxide Particles Formation Mechanism Of Ag-sn-o System

In this paper,the reactions process of AgSnO₂ electric material by reaction synthesis was discussed,which was explained the mechanism for nano-SnO₂ particles form in Ag-Sn-O system.In order to study the mechanism of nano-SnO₂ form process,we must analyze the process of reaction;find the reason for composing nano-SnO₂ particle in Ag-Sn-O system.In the process of synthesis AgSnO₂ composite material,the systems came into different areas of reaction as the same time of the reaction process.The systems in environment and inside were changed in these moments of reactions.When the surface on the particle in basal was covered with the first layer oxides,the system came into the moments that the reactions lacked oxygen.When diffuse coefficient of Sn atom was less than O atom in the basic,the atom of Sn could be oxide as it went into the inside basal.In other words,the difffusivity of O atom was more than Sn Atom in this moment since the concentration of Sn element was declined.The equilibrium diffusivity was considered the reaction boundary between the two synthesis processes.In the initialization of reaction process,the radius of nucleation,velocity of nucleation and the speed of shape were calculated by thermodynamics theory.Analyzing the factors of particle size in basal,the time boundary point was found,when the basal was covered completely by the first reactant.We can think that the area between initialization and intermediate were divided by the time boundary point.From through the different concentrations of Ag-Sn-O system with Sn O random walk behavior simulation and the mean square displacement and pair distribution function analysis by software of Materials Explorer.The difffusivity of Sn atom was lower than O Atom that the boundary point between intermediate and resultant was ascertained.At last,nano-SnO₂ particles were found in Ag-Sn-O system when concentration of the element Sn was lower than 1%.Sn concentration was much lower in the moment so the system could be considered as the model of watery solution.At the same time,the Sn atom could not diffuse a long distance.However,the O atom could transfer to other areas too. When the atom of Sn in the basic encountered the O atom,the particles SnO₂ were appearance.Because others Sn atom could not move to the reaction space and the nucleation was not grow up,the size of SnO₂particles were stayed on initialization.This is the reason of nano-SnO₂ particles form in Ag-Sn-O system.