Complex optimization of arc melting synthesis for bulk Cr₂AlC MAX-phase

A complex optimization of the arc melting synthetic approach was performed to enhance the phase purity of Cr₂AlC MAX-phase in the bulk form. Optimization steps included the initial ratio of 2Cr: xAl: 1C, variation through a change in Al content (i.e. x ranging from 1 to 1.5), tuning duration of the post-annealing thermal treatment and adjustment of the melting chamber pressure. The use of Cr₃C₂ as a precursor in place of Cr and C mixture has also been tried. It was found that Cr₂AlC MAX-phase forms as the predominant phase when a stoichiometric ratio 2Cr: 1.3Al: 1C is used. By keeping this stoichiometry constant, the melting chamber pressure was then adjusted to further improve the phase purity of the samples. It has been established that the use of Cr₃C₂ is not an appropriate way to improve sample purity and promote homogeneity in the carbon distribution. The establishment of an optimized arc fusion protocol for parental Cr₂AlC is a necessity for further successful mass synthesis of the substituted (Cr_1-xMn_x)₂AlC MAX-phase.