考察了几种不同掺锶量的理想化学配比锶磷灰石粉末在不同温度热处理后的相结构与化学成分,并观察其晶粒微观形貌与尺寸的变化。高温下HAP存在着分解和合并长大之间的竞争。随加热温度升高至1300℃,纯HAP基本不分解,但晶粒明显由600℃下20nm-40nm长大到1300℃下的-20μm:而Sr^2+取代Ca^2+固溶入磷灰石晶格后,因Sr^2+半径较大且对磷灰石晶体生长有抑制作用,使掺锶磷灰石分解过程比合并长大过程更为有利,因此,掺锶磷灰石晶体900℃便开始部分分解生成磷酸三钙;随温度逐渐升高,掺锶磷灰石晶体分解加剧,同时晶体有所长大但幅度不如纯HAP明显,1300℃下仍维持类等轴形状(440nm~730nm×220nm~370nm):增大锶固溶量则加剧分解程度。
Several stoichiometric strontium-incorporated hydroxyapatite powders with different content of strontium ion in place of calcium ion have been investigated on their thermal stabilities, including phase structure, chemical composition and crystal size and morphology at different temperatures. Results show that there exists a competition between phase decomposition and crystal growth of apatite. With the firing temperature climbing to 1300℃, no change happens to phase component of pure HAP, but the crystal apparently grows from 20 nm-40 nm at 600℃ to -20 μm at 1300℃. However, after some Sr^2+ incorporating into hydroxyapatite crystal by replacing equivalent Ca^2+, the larger ion radius and the inhibiting action on growth of apatite of Sr^2+ make the decomposition of Sr-incorporated hydroxyapatite (Sr-HAP) prior to its crystal growth. Thus, Sr-HAP starts to decompose into tricalcium phosphate at 900℃, which becomes serious at a higher firing temperature and more incorporation of Sr^2+. Although the crystal further grows up when increasing the firing temperature, the range of growth is much lower than that of pure HAP. At 1300℃, Sr-HAP also maintains a similar equiaxial crystal (440 nm-730nm×220nm-370nm).