Fabrication of porous gehlenite coating on Al₂O₃-ZrO₂-SiC composite ceramics and its in vitro biological activities

Porous gehlenite coatings on Al2O3-ZrO2-SiC composite ceramics were prepared by electro-spraying technique combined with reactive sintering method. The influences of gehlenite coating on the mechanical property of the ceramics and biological activity of the coating were investigated. The results indicated that the gehlenite coating has limited influences on flexural strength and fracture toughness of the ceramics, and the coating has elastic modulus of 82 GPa, hardness of 2.2 GPa, and adhesive strength of 1512 mN, suggesting its potential application in load-bearing ceramic implants. Simulated body fluid soaking test, CCK-8 and alkaline phosphatase activity assay demonstrated that the porous gehlenite coating has strong mineralization ability, which promotes proliferation and differentiation of MC3T3-E1 cells. These excellent biological performances can be attributed to the synergistic effect of the porous surface of the coating and its release of Ca2+ and Si4+.