Thermal Characterization of Hexaaluminate High Temperature Combustion Catalysts

摘要

Both Sr_(0.8)La_(0.2)MhAl_(11)O_(19) (SLMA) and Sr_(0.3)Ba_(0.5)La_(0.2)MnAl_(11)O_(19) (SBLMA) hexaaluminates had been prepared by the co-precipitation method. A solution of the nitrates of metal ions was prepared and precipitated using a large amount of ammonium carbonate under a constant pH (7-8). Thermal characterization of SLMA and SBLMA was examined by XRD, SEM, TEM and BET analyses. A monophasic hexaaluminate structure was formed and arrived surface areas of 20 - 30 m~2/g after calcinations up to 1200℃ for both SLMA and SBLMA. The surface area of SBLMA was larger than SLMA illustrating the superior thermal stability of the barium hexaaluminate. The high surface area for SBLMA compared to the SLMA could be understood from the microstructural change of pore size. The SBLMA possessed large pores than the SLMA to resist sintering under high temperature calcination. In the durable experiments, it was worthwhile to note that the surface area of the SBLMA maintained about 20 m~2/g after calcined at 1300℃ for 20 h.