Effect of Mn-Zn ferrite on apatite-wollastonite glass-ceramic (A-W GC).

Magnetic bioactive glass-ceramics (M GC) were prepared by doping apatite-wollastonite glass-ceramic (A-W GC) with Mn-Zn ferrite. The effect of different contents of Mn-Zn ferrite on the phase structure, magnetic property and bioactivity of A-W GC was investigated. X-ray powder diffraction results showed that A-W GC exhibited apatite, fluorapatite and wollastonite as the main phases. The doping of Mn-Zn ferrite caused the formation of a new phase Zn(0.75)Mn(0.75)Fe(1.5)O(4) in M GC. The amount of this new phase increased with increasing content of Mn-Zn ferrite. Under a magnetic field of 7.96 x 10(5) A m(-1), the saturation magnetization of M GC increased from 4.63 to 9.7 A m(2) kg(-1), but the coercive forces of M GC decreased from 2.39 x 10(4) to 7.56 x 10(3) A m(-1) as the Mn-Zn ferrite content increased from 5% to 20% in the material. The bioactivity of samples was evaluated by soaking in simulated body fluid (SBF). The results showed that the doping of Mn-Zn ferrite decreased the bioactivity of A-W GC dramatically. It took 7 days for an apatite layer to form on the surface of A-W GC, while at least 30 days was needed for an apatite layer forming on the surface of M GC.