Reactive spark plasma sintering of Ti₃SnC₂, Zr₃SnC₂ and Hf₃SnC₂ using Fe, Co or Ni additives

This work studied the effect of adding 10 at% Fe, Co or Ni to M-Sn-C mixtures with M = Ti, Zr or Hf on MAX phases synthesis by reactive spark plasma sintering. Adding Fe, Co or Ni assisted the formation of 312 MAX phases, i.e., Ti₃SnC₂, Zr₃SnC₂ and Hf₃SnC₂, while their 211 counterparts Ti₂SnC, Zr₂SnC and Hf₂SnC formed in the undoped M-Sn-C mixtures. The lattice parameters of the newly synthesized Zr₃SnC₂ and Hf₃SnC₂ MAX phases were determined by X-ray diffraction. Binary MC carbides were present in all ceramics, whereas the formation of intermetallics was largely determined by the selected additive. The effect of adding Fe, Co or Ni on the MAX phase crystal structure and the microstructure of the produced ceramics was investigated in greater detail for the case of M = Zr. A mechanism is herein proposed for the formation of M₃SnC₂ MAX phases.