论文部分内容阅读
采用水基羟基磷灰石(hydroxyapatite,HA)浆料,经冷冻干燥和烧结工艺(1 250℃烧结3 h)制备了层状多孔HA支架。研究了冷冻温度、干燥压力和干燥温度对水基HA浆料中溶剂升华行为的影响。结果表明:随着冷冻温度的降低,多孔HA支架的层间距逐渐减小,支架的升华时间增加;由于样品的干燥过程同时受到传热和传质的影响,随干燥压力的增加,干燥时间先降低后升高,同时干燥时间也随干燥温度的增加而降低,最终优化得到的最佳冷冻干燥工艺参数(压力和温度)分别为40 Pa和5℃,为冷冻干燥法制备多孔陶瓷过程中干燥时间的预测提供了依据。
Layered porous HA scaffolds were prepared by using hydroxyapatite (HA) slurry and freeze-drying and sintering (1 250 ℃ for 3 h). The effects of freezing temperature, drying pressure and drying temperature on the sublimation behavior of water-based HA slurries were investigated. The results showed that with the decrease of freezing temperature, the distance between porous HA scaffolds gradually decreased and the scaffolds’ sublimation time increased. As the drying process was affected by heat and mass transfer, with the increase of drying pressure and drying time Decreased and then increased, meanwhile the drying time also decreased with the increase of drying temperature. The final optimal freeze-drying process parameters (pressure and temperature) were 40 Pa and 5 ℃, respectively, which were the results of freeze-drying process for preparing porous ceramics The prediction of time provided the basis.