Study On Preparation And Characterization And Surface Modification Of In₂O₃/SnO₂ Nanopowders

This program is from general assembly department about new nano complex of inorganic-macromolecule shielded material. Nano indium, tin oxide etc. particles/polymer composite was studied. High transparence and electromagnetic shielded efficiency are asked. The transparency of organic glass is good, but it is nonconductor and has no shielded efficiency. When conducting particles are added to organic materials, they are conductive. But the composite must have enough pervious light gap between conducting particles, or the particle size is less than the wavelength of visible light. So preparation of indium, tin oxide (In2O3/SnO2) nano powders by promising method of sol - gel in liquid and surface modification were studied. We hope to summarize general nano preparation, modification and characterization methods.In the first part of the dissertation, the conducting mechanism and the current study on nano powders preparation methods of In2O3/SnO2 are reviewed.In the second part, the processes were studied on preparing In2O3/SnO2 nano powders in details by sol - gel method, and the electrical property was carefully studied of tin doped indium oxide (Sn-In2O3) nano powder too. The structure, morphology, particle size, specific surface area, and composition of In2O3/SnO2 nano powder were characterized by means of TG-DSC, FT-IR, XRD, SEM, EDS , TEM and BET.In the technology research of preparing In2O3/SnO2 nano powders, the influence factors were studied, such as reaction temperature, reaction pH value, dry technology, calcinating systems, reaction material concentration and ageing systems etc. The best technology conditions were reached finally.Through study on the electrical performance of Sn-In2O3 nano powder, some conclusions were drawn. When Sn-In2O3 precursor was calcinated at 700-1000 , low square resistance was got. The resistance was lower when Sn-In2O3 precursor was calcinated in vacuum than air condition. When SnO2 wt % was controlled for 10 %, the square resistance of Sn-In2O3 was minimum.Through the characterization of In2O3/SnO2 nano powders, some conclusions were drawn: SnO2 nano powder is rutile structure, and In2O3 and Sn-In2O3 nano powders are cubic structure. In2O3/SnO2 nano powders were well dispersing withspherical uniform grain, and the mean grain was 4-50 nm. The purity and composition uniformity were very high, and the specific surface area was 67-156 nm.In the third part, surface modification of Sn-In2O3 nano particle was studied and some conclusions were drawn finally. KH560 and KH570 were selected as surface modification agents, and the concentration of them was 0.5-1 wt %, and pH value was controlled for 5.4, and the best milled technology were 72 hours. Surface modified Sn-In2O3 nano powder was well dispersing in matrix.In the last part, conclusions were summarized.