title: Coupling of metals and biominerals: characterizing the interface between ferromagnetic shape-memory alloys and hydroxyapatite.
abstract: Durable, mechanically robust osseointegration of metal implants poses one of the largest challenges in contemporary orthopedics. The application of biomimetic hydroxyapatite (HAp) coatings as mediators for enhanced mechanical coupling to natural bone constitutes a promising approach. Motivated by recent advances in the field of smart metals that might open the venue for alternate therapeutic concepts, we explore their mechanical coupling to sputter-deposited HAp layers in a combined experimental-theoretical study. While experimental delamination tests and comprehensive structural characterization, including high-resolution transmission electron microscopy, are utilized to establish structure-property relationships, density functional theory based total energy calculations unravel the underlying physics and chemistry of bonding and confirm the experimental findings. Experiments and modeling indicate that sputter-deposited HAp coatings are strongly adherent to the exemplary ferromagnetic shape-memory alloys, Ni-Mn-Ga and Fe-Pd, with delamination stresses and interface bonding strength exceeding the physiological scales by orders of magnitude.
authors.affiliation: †Leibniz-Institute for Surface Modification (IOM), Permoserstrasse 15, 04318 Leipzig, Germany.|‡Soft Matter Physics Division, Faculty of Physics and Earth Sciences, University of Leipzig, Linnéstrasse 5, 04103 Leipzig, Germany.
authors.forename: Uta
authors.initials: U
authors.lastname: Allenstein
authors.affiliation: ¶Fraunhofer Institute for Mechanics of Materials (IWM), Walter-Hülse-Strasse 1, 06120 Halle, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Selle
authors.affiliation: †Leibniz-Institute for Surface Modification (IOM), Permoserstrasse 15, 04318 Leipzig, Germany.
authors.forename: Meike
authors.initials: M
authors.lastname: Tadsen
authors.affiliation: ¶Fraunhofer Institute for Mechanics of Materials (IWM), Walter-Hülse-Strasse 1, 06120 Halle, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Patzig
authors.affiliation: ¶Fraunhofer Institute for Mechanics of Materials (IWM), Walter-Hülse-Strasse 1, 06120 Halle, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Höche
authors.affiliation: ‡Soft Matter Physics Division, Faculty of Physics and Earth Sciences, University of Leipzig, Linnéstrasse 5, 04103 Leipzig, Germany.
authors.forename: Mareike
authors.initials: M
authors.lastname: Zink
authors.affiliation: †Leibniz-Institute for Surface Modification (IOM), Permoserstrasse 15, 04318 Leipzig, Germany.|∥Translational Center for Regenerative Medicine, University of Leipzig, Philipp-Rosenthal-Strasse 55, 04103 Leipzig, Germany.|⊥Faculty of Physics and Earth Sciences, University of Leipzig, Linnéstrasse 5, 04103 Leipzig, Germany.
authors.forename: Stefan G
authors.initials: SG
authors.lastname: Mayr
mesh_terms: D000497:Alloys / Q000737:chemistry; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D059346:Magnets / Q000737:chemistry*; D008422:Materials Testing; D008670:Metals / Q000737:chemistry*
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; D008670:Metals; D017886:Durapatite
keywords: DFT; HR-TEM; adhesion; hydroxyapatite; smart metals