Low Temperature Combustion Synthesis Technology Preparation Of ¦Á-al <sub> 2 </ Sub> O <sub> 3 </ Sub> Powder

Al2 O3 powder was prepared by the method of Low temperature Combustion Synthesis (LCS ) with A1(NO3)3-9H20 and CO (NH2) 2. The original production was foamy substance that can be grinded easily , and then A12O3 powder was received . The configuration and microstructure of production ,the effect of heating temperature and chemistry match ratio on reaction and production, the effect of calcining temperature and time on the changes of production crystal were studied by XRD, TEM , DTA and Microscope. Furthermore, reaction thermodynamics, reaction mechanism and forming mechanism of crystal were analyzed. The crystal lattice constants of production were also calculated.Conclusions can be made by experimental observation as following: a-Al2O3 powder can be prepared by Low temperature Combustion Synthesis when temperature is lower (450 C). Heating temperature plays a key role of ignition , otherwise the raw materials cannot be ignited when heating temperature is lower than 400C. There are phenomena that gestation time was shortened, combustion time was lasted, and combustion was accelerated as heating temperature increased. The diffraction intension of a-AljCh powder was the strongest when the quality match ratio of Aluminum nitrate and Urea is 2.5: 1. The production was gray when the quality match ratio of Aluminum nitrate and Urea is less than 2.5: 1. The raw materials cannot be reacted at 500C when the quality match ratio of Aluminum nitrate and Urea was 3.5: 1. The production was amorphous when heating temperature was 300C . It was found that r-Al2O3 occurred 700C and 1.5 hours, a-Al2O3 was occurred at 1000C and 1.5 hours after the production was calcined at different temperature and time. Examined by TEM, the production was slice shape in which there are many fine grains and the size of slices is 200nm~2 u m and the most part of it is 500nm when the quality match ratio of Aluminum nitrate and Urea was 2.5: 1 and raw materials was ignited at 500 C . The size of slices is 200nm~400nm when the quality match ratio of Aluminum nitrate and Urea was 2.5: 1 and raw materials was ignited at 300C . Granularity can be 30~60nm after the production was ball-milled for 5 hours.