Unconventional synthesis of Mg x C y Ni3: Synergic combination of mechanical alloying, SHS and isothermal heating

• Published in: Journal of materials science 2004-08, Vol.39 (16-17), p.5333-5337
• Main Authors: Ferretti, M, Bruzzone, G, Magnone, E, Rubino, S, Bernini, C, Martinelli, A
• Format: Article
• Language: English
• Subjects: Conversion; Graphite; Heating; High temperature; Isothermal treatment; Materials science; Mechanical alloying; Methods; Perovskites; Powder compacts; Scanning electron microscopy; Self propagating high temperature synthesis; Stoichiometry; X ray powder diffraction
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1023/B:JMSC.0000039239.47777.f9

Several methods have been tested in order to prepare the perovskite type compound MgxCyNi3 applying the mechanical alloying (MA), the self-propagating high-temperature synthesis (SHS) and the isothermal heating techniques in the different steps of preparation. These methods may be summarized as follows: method MCN-1) synthesis of the MgxCyNi3 phase through MA of Mg2Ni (previously synthesised by isothermal heating) and selected amounts of graphite and Ni, followed by isothermal treatment; method MCN-2) synthesis of the MgxCyNi3 phase applying the SHS technique using powder compacts; method MCN-3) synthesis of an eutectic sample composed of Ni and MgNi2 by means of isothermal heating, subsequent MA with graphite and final synthesis of MgxCyNi3 by means of SHS.The methods MCN-2 and MCN-3 proved their validity to the synthesis of the desired compound with two main important results: complete conversion of the reactants into MgxCyNi3 and control of the stoichiometry in the final product. For instance method MCN-1 shows instead a very low degree of conversion of the reactants.All the phases obtained after each preparation step (MA, SHS, isothermal heating) have been characterized by means of X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) coupled with electron dispersive spectroscopy (EDS).