Abstract
One of the key issues involved in successfully achieving HA ceramic body without defects using colloidal processing technique, is the preparation of homogeneous and high solid loading HA ceramic suspension with suitable rheological properties. This could be achieved not only via adjusting the type and amount of the dispersing agent, but also via controlling the properties of the HA powder. The maximum solid loading suspension that could be prepared from the as received powder was found to be 14 vol%. This value is too low to be successfully applied in casting processes. While, the treatment of the as received powder via calcination process prior to suspension preparation was found to play a very versatile role. A solid loading of 57 and 59 vol% would prepare from HA powder calcined at 1000 and 1100 degrees C, respectively with applying the optimum amount of sodium polyacrylate dispersant. The suspensions produced from the calcined powder was found to have acceptable rheological properties for casting processes in terms of low particle interaction, lower number of floc and floc network and higher fluidity.