Mechanically Reinforced Xonotlite/Sodium Alginate Composites by Magnesium‐Rich Amorphous Layer

ABSTRACT Tooth enamel, renowned for its exceptional mechanical properties, is composed of highly organized hydroxyapatite nanowires, intricately modified with an amorphous phase enriched with metal ions such as magnesium and iron. These amorphous layers enriched with metal ions play a pivotal role in significantly enhancing the mechanical performance of enamel. Drawing inspiration from this unique natural structure, we employed magnesium ion regulation to achieve the controllable synthesis of xonotlite nanowires coated with a magnesium‐rich amorphous layer. Utilizing a volatile self‐assembly strategy, we successfully fabricated composite films composed of xonotlite nanowires and sodium alginate. Subsequently, enamel‐like bulk composite materials were synthesized through a laminated hot‐pressing technique. The experimental results demonstrate that the fabricated xonotlite/sodium alginate (SiCa‐Mg/SA) bulk composites exhibit remarkable mechanical properties, including a bending strength of 96.4 MPa, a hardness of 1.11 GPa, and a modulus of 21.4 GPa. Notably, the bending strength of these composites is 9.2% higher than that of their counterparts lacking the amorphous layer. This study not only underscores the efficacy of amorphous intergranular phase structures in reinforcing composite materials but also provides a novel strategy for the preparation of artificial bioinspired composites with enhanced mechanical performance.