Metal/oxide composites: mechanisms of the formation from the thermal decomposition of LaNi5

MA. F. TORRESAN; L.V. MOGNI; M.R ESQUIVEL

Procedia Materials Science

Pergamon-Elsevier

Lugar: Amsterdam; Año: 2015 vol. 8 p. 1108 - 1117

2211-8128

The formation of metal/oxide composites from the thermal decomposition of LaNi5 is analyzed by TG and DSC between room temperature and 700 ºC. The reaction products are characterized by XRD, SEM and EDS. Based on the results obtained, the following global mechanisms are proposed: For temperature range between 160 ºC and 600 ºC 2LaNi5 + 13/2O2  ® La2O3 + 10NiO                                                                                                                                                 (1) For temperature range higher than 600 ºC, two mechanisms were proposed as presented for each following equation:  LaNi5 + 7/2O2® LaNiO3 + 4NiO                                                                                                                                                  (2) 2LaNi5 + 7/2O2 ® La2O3 + Ni ® La2O3 + NiO ® LaNiO3 + 10NiO                                                                                            (3) The conditions that promote the formation of metal/oxide composites are discussed according to these results.