Study of the process of mechanochemical activation to obtain aurivillius oxides with n=1

Mechanochemical activation has been successfully used as an alternative met hod for producing Aurivillius oxides with n = 1, like Bi2MoO6, Bi2VO5.5, an d Bi2VO2. The analysis of the mechanoactivated materials by SEM and TEM all ows the study of the mechanisms involved in the process of mechanical activ ation and the occurrence of mechanosynthesis. It is observed that if the am orphization of all the starting oxides is achieved during the process, evid ence of mechanosynthesis, i.e., the synthesis of the final product, is foun d in the resulting particles. The phases obtained either cannot be synthezi sed by the traditional solidstate reactions or show special characteristics , all of which confirms that the mechanisms of phase formation involved in the mechanical and the thermal activations are different. Further annealing at higher temperatures makes all these structures go back to the phases tr aditionally obtained by thermal activation. (C) 2001 Academic Press.