Texture development of hydroxyapatite ceramics by colloidal processing in a high magnetic field followed by sintering

Hydroxyapatite (HAP, Ca10(PO4)6(OH)2) is a main component in the human body and teeth, and a specific crystal orientation is required because of the different properties for each crystal plane. In this study, two types of hydroxyapatite powders were used for the fabrication of a textured HAP. The effects of the processing parameters on the orientation, such as de-agglomeration by ultrasonication and milling procedures, applied magnetic field and sintering temperatures, were examined. Using the de-agglomerated particle by a milling procedure, it is possible to control the particle orientation, but when using heavily agglomerated particles, it was impossible to control the particle orientation by applying a high magnetic field. Highly textured HAP can be fabricated by slip casting using a well-dispersed suspension in a high magnetic field followed by sintering above 1373 K.