ABSTRACT: In this study, we developed a dual-coating approach to enhance the mechanical and bioactive properties of zirconia- toughened alumina (ZTA) bioceramics for biomedical implant applications. The method applies a two-step coating process: a calcium titanate (CaTiO3) layer on the tissue-contacting region to promote bioactivity and osseointegration, and a high-entropy alloy (HEA, Fe0.25Pt0.25Zr0.25Mg0.25) coating on the remaining surface to improve mechanical strength and durability. ZTA substrates were synthesized through high-energy ball milling and sintering at 1400 °C, yielding a baseline hardness of 2.97 GPa and an elastic modulus of 79.2 GPa, as measured by nanoindentation. Molecular dynamics (MD) simulations, performed using LAMMPS with a hybrid Embedded Atom Method, Buckingham, and Lennard-Jones potential framework, produced a hardness range of 2.49−2.95 GPa, consistent with experimental results. The HEA coating increased the composite hardness to 2.63 GPa, reduced principal stresses from 1330 to 546 MPa, and improved thermal conductivity with a z-axis heat flux of 80 eV/fs·Å2, minimizing localized overheating. The CaTiO3 coating slightly increased hardness to 2.49 GPa while enhancing bioactivity through improved apatite formation and cell proliferation. Stress and thermal analyses confirmed the HEA’s mechanical stability and the CaTiO3’s contribution to biological integration. This dual-coating method addresses ZTA’s challenges, including low-temperature degradation and limited bone bonding, providing a framework for high-performance, biocompatible dental implants.
