Structural-phase surface composition of porous TiNi produced by SHS

Abstract

The study aimed to characterize the structural-phase composition of the porous SHS TiNi surface explored by the GIXRD method. The surface layers at a depth of up to 100 nm mainly consist of amorphous nanocrystalline intermetallic oxycarbonitrides Ti4Ni2(O, N, C) with nonmetallic inclusions of different structural variants and routes of origin. Fine-porous alloys were synthesized at ignition temperatures of 450 °C–480 °C. A distinct feature of the surface of crystalline phases therein was shown to be a low degree of crystallinity (up to 40%) and presence of multifarious glass and cermet phases evident as NiSi2, NaAlSiO (SO4), SiO2, MgSi2, and CaCO3. Conversely, large-pore alloys ignited at temperatures of 280 °C–330 °C have a higher degree of crystallinity (up to 70%). An individually selected GIXRD technique and precision structural phase analysis are capable to determine a set of other superficial nonmetallic and cermet phases reported as CaTiO3, Si (P2O7), CaSiO3, MgAl2O4, TiNiAl, as well as the Ti3SiC2MAX phase.