en گروه سرامیک Ceramic Materials and Engineering Research Paper Research Paper Na super ionic conductive (NASICON) materials are ceramics with three-dimensional scaffolds. In this study, Li_1.4Al_0.4Ti_1.6(PO₄)₃ with NASICON structure was synthesized by Pechini method. As a result, a sample having a total conduction of 1.18×10^-3 S cm^-1 was attained. In addition, various parameters were studied to obtain high value of conductivity, by optimizing the process. The optimization was made using L16 Taguchi based orthogonal array, followed by ANOM, ANOVA and stepwise regression. As a result, the optimum synthesis parameters can be obtained, while pH of the solution was adjusted to 7. The ratio between the concentration of citric acid to metal ions and ethylene glycol concentration stuck to 1 and 2.5, respectively. The best heat treatment can be carried out with a combination of pyrolysis at 600 ºC and sintering at 1000 ºC.  NASICON, Pechini, Ionic conductivity, ANOM, Stepwise regression, Electrochemical impedance spectroscopy, LATP, Peroxotitanium. 60 71 http://ijmse.iust.ac.ir/browse.php?a_code=A-10-1547-2&slc_lang=en&sid=1 M. R. Ghaani mohammad.ghaani@ucd.ie 1800319475328460010349 1800319475328460010349 Yes Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran, Iran P. O. Box 15875-4413 P. Marashi pmarashi@aut.ac.ir 1800319475328460010350 1800319475328460010350 No Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran, Iran P. O. Box 15875-4413