Sequential elucidation of the β-Ca3(PO4)2/TiO2 composite development from the solution precursors

Synthesis, Structural, and Mechanical Behavior of β-Ca3(PO4)2–ZrO2 Composites Induced by Elevated Thermal Treatments

Biocompatible β-Ca₃(PO₄)₂ and mechanically stable t-ZrO₂ composites are currently being combined to overcome the demerits of the individual components. A series of five composites were synthesized using an aqueous precipitation technique. Their structural and mechanical stability was examined through X-ray diffraction, Rietveld refinement, FTIR, Raman spectroscopy, high-resolution scanning electron microscopy, and nanoindentation. The characterization results confirmed the formation of β-Ca₃(PO₄)₂–t-ZrO₂ composites at 1100 °C. Heat treatment above 900 °C resulted in the degradation of the composites because of cationic interdiffusion between Ca²⁺ ions and O⁻² vacancy in Zr⁴⁺ ions. Sequential thermal treatments correspond to four different fractional phases: calcium-deficient apatite, β-Ca₃(PO₄)₂, t-ZrO₂, and m-ZrO₂. The morphological features confirm in situ synthesis, which reveals abnormal grain growth with voids caused by the upsurge in ZrO₂ content. The mechanical stability data indicate significant variation in Young’s modulus and hardness throughout the composite.

In situ formation, structural, mechanical and in vitro analysis of ZrO2/ZnFe2O4 composite with assorted composition ratios

The investigation underline the in situ formation of ZrO₂/ZnFe₂O₄ composites and the resultant structural, morphological, mechanical and magnetic properties. The characterization results ensured the crystallization of tetragonal ZrO₂ (t-ZrO₂) and ZnFe₂O₄ phases at 900 °C. Depending on Zn²⁺/Fe³⁺ content, the composite system revealed a gradual increment in the phase yield of ZnFe₂O₄. The significance of monoclinic ZrO₂ (m-ZrO₂) is also evident in all the systems at 900 °C; however, the incremental heat treatment to 1300 °C indicated its corresponding loss, thus indicating the reverse m- → t-ZrO₂ transition. The crystallization of ZnFe₂O₄ as a secondary phase in the t-ZrO₂ matrix is also affirmed from the morphological analysis. Mechanical studies accomplished good uniformity in all the investigated compositions despite the variation in the phase content of ZnFe₂O₄ in composite system. All the t-ZrO₂/ZnFe₂O₄ composites ensured strong ferrimagnetic features and moreover better biocompatibility and non-toxicity characteristics were displayed from in vitro tests.

Investigation on the structural, mechanical and in vitro biocompatibility features of CaZr4 (PO4 )6 influenced by Zn2+ substitutions

The present study explores the possibility of Zn²⁺ substituted calcium zirconium phosphate [CaZr₄ (PO₄ )₆ ] as a potential replacement for the existing materials in load bearing orthopedic applications. Pure CaZr₄ (PO₄ )₆ ) and wide range of Zn²⁺ substitutions in CaZr₄ (PO₄ )₆ have been synthesized through citrate assisted sol-gel technique. The characterization results confirmed the extraordinary structural stability displayed by CaZr₄ (PO₄ )₆ until 1,550°C. Further, the flexibility of CaZr₄ (PO₄ )₆ lattice to accommodate 40 mol% of Zn²⁺ has been determined. The microstructures of CaZr₄ (PO₄ )₆ and Zn²⁺ substituted CaZr₄ (PO₄ )₆ demonstrated irregular sized grains and cracks alongside the negligence to obtain definite grain boundaries. This has been reflected in the moderate mechanical properties of the investigated specimen; nevertheless, Zn²⁺ substituted CaZr₄ (PO₄ )₆ displayed enhanced mechanical stability. Further, in vitro tests signified the remarkable biocompatibility and alkaline phosphatase activity of Zn²⁺ substituted CaZr₄ (PO₄ )₆ .