Wang B C, Chang E, Lee T M, Yang C Y
Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan, R.O.C.
J Biomed Mater Res. 1995 Dec;29(12):1483-92. doi: 10.1002/jbm.820291204.
With three kinds of plasma-sprayed hydroxyapatite coatings (HACs) prepared, the objectives of this study were (1) to establish the calibration methods for quantitatively measuring the concentration of impurity phases and the degree of crystallinity of the HACs, and (2) to explore the effects of postheat treatments at various temperatures in vacuo on the changes of phases and crystallinity of the HACs. By the internal standard method used, the concentrations of impurity phases, such as alpha-TCP, beta-TCP, and TP, of the assprayed HACs were significantly higher than those measured by the direct intensity-ratio method, and the CaO phase was lower than the direct intensity-ratio method. When the HACs were heat treated in the temperature interval 630-850 degrees C, the concentrations of impurity phases obviously decreased, and the coating crystallinity apparently increased. After annealing at 850 degrees C, an HAC consisting of at least 95% crystallinity with few impurity phases was obtained. As the annealing temperatures in the interval 850-1000 degrees C were applied, however, the HA phase seriously decomposed, resulting in the appearance of a large number (higher than 20 wt%) of impurity phases in the HACs. This work suggests that the optimum heat treatment conditions in vacuo for maximizing crystallinity and minimizing impurity phases of the HACs do not occur at the same temperature.
制备了三种等离子喷涂羟基磷灰石涂层（HACs），本研究的目的是：（1）建立定量测量HACs中杂质相浓度和结晶度的校准方法；（2）探究在真空中不同温度下进行后热处理对HACs相变化和结晶度的影响。采用内标法时，喷涂态HACs中杂质相（如α-TCP、β-TCP和TP）的浓度明显高于直接强度比法测量的值，而CaO相则低于直接强度比法测量的值。当HACs在630 - 850℃的温度区间进行热处理时，杂质相浓度明显降低，涂层结晶度明显提高。在850℃退火后，得到了结晶度至少为95%且杂质相较少的HAC。然而，当在850 - 1000℃的温度区间进行退火时，HA相严重分解，导致HACs中出现大量（高于20 wt%）的杂质相。这项工作表明，使HACs结晶度最大化和杂质相最小化的最佳真空热处理条件并非在同一温度下出现。
