Первопринципное исследование механизмов межатомного взаимодействия на границе раздела титан-керамика на основе фосфатов кальция

Abstract

First-principles study to investigate the effect of substitutional Si doping in the amorphous calcium phosphate (aHA) structure on the work of adhesion, integral charge transfer, charge density difference (CDD) and theoretical tensile strengths between an aHA coating and amorphous titanium dioxide (aTiO[2]) substrate will be presented. Our calculations demonstrate that substitution of a P atom by a Si atom in each of the six PO4 groups in aHA with the creation of OH-vacancies as charge compensation results in a significant increase of the bonding strength of the coating to the substrate. The work of adhesion of the optimized Si-doped interfaces reaches a value of up to -2.52 J·m{-2}, which is significantly higher than for the stoichiometric aHA/aTiO[2]. CDD analysis indicates that the dominant interactions at the interface have significant covalent character. Thus, our calculations therefore demonstrate that the presence of Si in the aHA structure strongly alters not only the bioactivity and resorption rates, but also the mechanical properties of the aHA/TiO[2] interface