the effect of microwave settings on hap sintering

Hydroxyapatite (hap, ca10(po4)6(oh)2), a calcium phosphate bio ceramic which is chemically similar tonatural bone mineral, is widely used as a scaffolding material in bone tissue engineering. in this study,hydroxyapatite (hap) ceramics were sintered using microwave in one- and two-step heat treatment. thesintering temperatures in the first heat treatment step were in the range of 965-1000 °c without isothermalholding, and the power levels of the microwave were set at 600, 750, and 900 w. the temperatures in thesecond heat treatment step were 600, 735, and 860 °c. of note, hap-to-tricalcium phosphate (tcp) phasetransformation was not detected at 1000 °c; instead, the preferred growth of (211) planes corresponding tothe circular morphology was observed. as observed in the xrd images, crystallite degradation occurredin two-step sintered samples. in addition, the sem micrographs indicated that the open porosity in the twostepheat treated samples was more than that of samples which were heat treated in one step. in case thesintering temperature was set at 1000 °c, the maximum density values of 92 % and 95 % were obtainedfor one- and two-step sintered samples, respectively.