Synthesis of (Tix,W۱-x)۳SiC۲ MAX phase by mechanical milling

This study has investigated the synthesis of (Ti۱-xWx)۳SiC۲ MAX phase via high energy ball milling, and the effect of heat treatment and excess Si on the purity of synthesized powder were explored. In this regards, different mixtures of Ti, Si, and C were ball milled by a planetary ball mill for various milling times up to ۱۵h. The phase evolution of products was studied by X-ray diffraction (XRD), and the morphological changes monitored by a field emission scanning electron microscopy (FESEM) equipped with energy-dispersive spectroscopy (EDS). The results showed that after ۱۵ hours of ball milling the reaction started, and resulted in Ti۳SiC۲ and TiC formation. The as-synthesized powders were then compacted and heat treated at ۶۰۰, ۱۰۰۰, ۱۲۵۰ and ۱۴۰۰˚C. Heat treatment caused to proceed in the reaction between the intermetallic compounds in Si-Ti system and TiC, and led to increasing the purity of Ti۳SiC۲. In a separate run, a non-stoichiometric composition of Ti: Si:C= ۳:۱.۲:۲ was ball milled for ۱۵ h, and heat treated at ۱۲۵۰˚C. The XRD results showed that the purity of the product is higher than the stoichiometric composition. The addition of W to Ti۳SiC۲ was also explored. In this regard, the synthesis of (Ti۱-xWx)۳SiC۲ component (x= ۰.۸, ۰.۵) was investigated, and the results showed that some W incorporated in Ti۳SiC۲ structure, and the WC and TixW۱-x formed during the process.

کلیدواژه ها:

Ternary Carbide ، Ti۳SiC۲ ، MAX phase ، High energy ball milling