Low Temperature Presureless Sintering Behavior of Hydroxyapatite Powders

The sintering behavior of Hydroxyapatite(HA) powders prepared by precipitation method was investigated by means of XRD,SEM and thermal dilatometer.The results showed that ball-milling treatment and calcining temperature exert an influence on sintering process of HA.Ball-milling could reduce aggregation.The average size of particles calcined at different temperatures is less than 100 nm.The temperature of the highest shrinkage of sintering body is 1050 ℃,100 ℃ lower than that without ball-milling.On the same sintering condition,the powders calcined at 700 ℃,750 ℃ and 800 ℃ showed different sintering behaviors.The highest shrinkage is 18%,21% and 16.8%,respectively.And the temperature corresponding to the highest shrinkage rate is respectively 990 ℃,950 ℃ and 1000 ℃.The powder calcined at 750 ℃ possesses a better sintering behavior.A relative density of 98% can be obtained when the powder is pressureless sintered at 1050 ℃.