前驱体转化法制备复相磷酸钙

对化学沉淀法制备复相磷酸钙过程中无定型磷酸钙（TCP）前驱体（钙磷物质的量比为1.500)和羟基磷灰石（HA）前驱体（钙磷物质的量比为1.667）的相互转化进行了系统研究。结果发现，体系pH=11.0时，TCP前驱体可以继续同一定量的Ca²⁺反应，在24h内完全转化为HA前驱体；相反，HA前驱体与PO^3-₄反应向TCP前驱体转化很慢。应用前驱体转化法制备了钙磷物质的量比分别为1.600和1.636的复相磷酸钙，发现900℃灼烧2h后得到α-TCP/HA复合物，与相同条件下传统化学沉淀法制得的产物α-TCP/β-TCP/HA有一定差别。

Effect of precursor conversion on the synthesis of biphasic calcium phosphates

The conversion of a TCP precursor (amorphous calcium phosphate with n(Ca)/n(P)=1.500) and of an HA precursor (amorphous calcium phosphate with n(Ca)/n(P)=1.667) were investigated in the synthesis of biphasic calcium phosphate ceramics. The results showed that after reaction for 24h at pH 11.0, the TCP precursor reacted completely with the required quantity of Ca²⁺, whilst the HA precursor only partly reacted with PO^3-₄. Biphasic α-TCP/HA composites were synthesized by the reaction of TCP precursors and Ca²⁺ after calcination at 900℃ for 2h, whereas triphasic α-TCP/β-TCP/HA composites (n(Ca)/n(P)=1.600 and n(Ca)/n(P)=1.636) were synthesized by conventional chemical precipitation methods under the same conditions.