The comparative structural-phase analysis of the surface of macro and micro porous SHS TiNi

The structural-phase composition of the implant surface is important for the biocompatibility of macro-and microporous nickelide titanium alloys. On the surface of the pore walls, the peritectic melt Ti2Ni interacts diffusively with gaseous impurities of carbon, nitrogen and oxygen, released during the synthesis process at the interaction of the charge components. Thus, a surface layer is formed, the thickness and the structural-phase composition of which depends on the initial conditions of the synthesis. Comparative structural-phase analysis by XRD and EDS, SEM methods have shown that the surface of macro and microporous SHS-TiNi alloys is a multiphase amorphous-nanocrystalline complex of intermetallic oxycarbonitride Ti₄Ni₂(O,N,C), intermetallic phases TiNi (B2, B19′), residual amorphous phase, glass-ceramic and metal-ceramic inclusions: CaTiO₃, Si (P₂O₇), CaSiO₃, MgAl₂O₄, TiNiAl. On radiographs of macroporous alloys, a high intensity of the structural lines of the main and secondary phases was revealed in comparison with microporous alloys due to the less developed surface and different thickness of the surface layer. Furthermore, in the macroporous samples, fracture areas free from the surface oxycarbonitride layer were detected. Therefore, as a result of the X-ray beam hit, the structural lines from the TiNi intermetallic compound (B2, B19′) are more intense.