Chemically complex double solid solution MAX phase-based ceramics in the (Ti,Zr,Hf,V,Nb)-(Al,Sn)-C system

Abstract

Chemically complex MAX phase-based ceramics in the (Ti,Zr,Hf,V,Nb)-(Al,Sn)-C system were synthesised by reactive hot pressing for 30 min at 1250–1450°C under a load of 30 MPa for the first time in this work. The dense bulk ceramics contained chemically complex double solid solution MAX phases, each comprising five M-elements and two A-elements. The predominant 211 (Ti0.23,Zr0.18,Hf0.20,V0.11,Nb0.28)2(Al0.42,Sn0.58)C MAX phase characterised all ceramics, while the 312 (Ti0.23,Zr0.31,Hf0.31,V0.08,Nb0.08)3(Al0.36,Sn0.64)C2 and 211 (Ti0.26,Zr0.07,Hf0.07,V0.47,Nb0.13)2(Al0.66,Sn0.34)C MAX phases were only present in the ceramics sintered at 1350–1450°C. A limited amount (4–5 vol%) of parasitic phases (mainly, binary intermetallics) was found in the pseudo-binary carbide-free ceramics sintered at 1350–1450°C.