Study On Preparation Of Nanometer Tin Oxide And Indium Oxide Powder By Liquid Phase Method

Tin oxide and indium oxide are important wide bandgap N-type oxide semiconductors.With the features of large thermal conductivity,good thermal stability,high activity,and high visible light transmittance,they have been widely used in the field of optoelectronic materials.As the raw material powders of the ITO target for flat panel display,the powder characteristics have an important influence on the performance of the target.Adopting appropriate preparation methods and process parameters to effectively adjust the crystal structure,particle size and crystallinity of the powder,and obtaining excellent performance of tin oxide and indium oxide is the key basis for the preparation of ITO targets.In this paper,high-purity metal tin?4N?and indium?4N?were used as raw materials,respectively.Tin oxide and indium oxide nanopowders were respectively prepared by nitric acid oxidation-hydrothermal method and acid solution-ammonia precipitation method.The intermediate and final powders were characterized by SEM,TEM,TG-DSC,BET,etc.The influence of process parameters in the preparation process was systematically studied,and the powder formation processes also were analyzed.It provides a theoretical guide for the better preparation of a single crystal structure,controllable particle size and high crystallinity powder.The main research results of this article are as follows:?1?The tin oxide powder was prepared by nitric acid oxidation-hydrothermal method,the process parameters of pH value,hydrothermal temperature and hydrothermal time on the effect of micro-characteristics of products were investigated,and the formation process of tin oxide was analyzed.The results show that pH,hydrothermal temperature and hydrothermal time mainly affect the particle size,crystallinity and dispersibility of the hydrothermal product tin oxide,pH value,and have no effect on the crystal form of tin oxide.Comprehensive consideration of the product particle size and crystallinity,under pH value of 5,hydrothermal temperature of 180?and hydrothermal time of 6 h,the highly active and nearly spherical nanopowder can be obtained.The size of particle is about 3.5?6.0 nm,and specific surface area is up to 179.34 m²/g.?2?To further improve the crystallinity of tin oxide,the nano-tin oxide was calcined,and the effect of calcination temperature and calcination time on the microscopic characteristics of tin oxide was studied.The results show that the calcination temperature has a great influence on the crystallinity and particle size of the product;the calcination time mainly affects the product morphology.Under the calcination process with a calcination temperature of 550?and a calcination time of1.5 h,highly active near-spherical nano-powders with a particle size of 15?20 nm and a specific surface area of 27.73 m²/g can be prepared.?3?In the preparation of indium oxide nanopowders by acid solution-ammonia precipitation method,the effects of acid ion type,precipitation reaction temperature and aging time on the microscopic characteristics of the precursor during the precipitation process were investigated,and the formation process of the precursor powder was analyzed.The results show that the precursor obtained after HNO₃/H₂SO₄system precipitation at room temperature tends to be more spherical than the HNO₃/HCl system.The particle size is about 15?40 nm,the crystallinity is higher,and the calcination is at 750?for 3 h,near-spherical nano-indium oxide powder of 20?70nm can be obtained.When the precipitation reaction temperature is increased from room temperature to 55?,the crystallinity of the indium hydroxide precursor is improved,and the morphology is also converted into fine indium hydroxide self-assembled flower-like cluster structure of the particles.When the aging time is extended from 3 h to 24 h,the particles of the precursor indium hydroxide grow up,the morphology tends to be stable,and the three-dimensional flower-like cluster structure is gradually regular and crystalline improve.?4?The precursor indium hydroxide is transformed into cubic indium oxide by calcination with high temperature.The effect of the calcination process on the microscopic properties of In₂O₃ powder was studied.The results show that the calcination process mainly affects the particle size and crystallinity of indium oxide,and has no effect on the crystal form of indium oxide.After calcination at 750?for 3h,three-dimensional flower-like cluster indium oxide powder with high crystallinity,high activity,and primary particle size of nanometers can be obtained;when the calcination temperature is increased to 1150?,the particles grow up obviously,and nearly spherical particles with size of 0.8?1.5?m.