Enhancing the zircon yield through the addition of calcium phosphates into ZrO 2 -SiO 2 binary systems: synthesis and structural, morphological, mechanical and in vitro analysis.

The crystallization of ZrSiO 4 is generally accomplished by the addition of mineralizers into ZrO 2 -SiO 2 binary oxides. The current investigation aimed to investigate the effect of adding calcium phosphates into ZrO 2 -SiO 2 binary oxides on the yield of ZrSiO 4 . The concentration of calcium phosphate additions were varied to obtain ZrSiO 4 that fetches improved mechanical and biological properties for application in hard tissue replacements. The findings highlight the significant role of Ca 2+ and P 5+ in triggering the ZrSiO 4 formation via their accommodation at the Zr 4+ and Si 4+ sites. Especially, calcium phosphate additions trigger the t- → m-ZrO 2 transition beyond 1000 °C, which consequently reacts with SiO 2 to promote ZrSiO 4 formation. Calcium phosphates are accommodated at the lattice sites of ZrSiO 4 with a maximum limit of 20 mol%, beyond which the crystallization of β-Ca 3 (PO 4 ) 2 is noticed. The optimum amount of 20 mol% of calcium phosphates displayed a better strength than that of all the investigated specimens. More than 80% of cell viability in MG-63 cells was invariably determined in all the calcium phosphate-added ZrSiO 4 systems.