Knowles J C, Talal S, Santos J D
IRC in Biomedical Materials, Queen Mary & Westfield College, London, UK.
Biomaterials. 1996 Jul;17(14):1437-42. doi: 10.1016/0142-9612(96)87287-5.
Glass was incorporated into hydroxyapatite (HA) to act as a sintering aid in order to improve the mechanical properties. The glass was added at 2 and 4 wt% and the powders compacted uniaxially. The compacts were sintered at a variety of temperatures (1200, 1250, 1300 and 1350 degrees C) and the effects of the glass addition and the firing temperature were studied to determine their effects on the sintering process. It was found that the glass promoted some phase changes, related to the amount of glass added to the composite. At 1200 and 1250 degrees C, some beta-tricalcium phosphate (TCP) was found with the residual being HA. However, at 1300 and 1350 degrees C, both beta- and alpha-TCP were formed. The 4 wt% addition, as expected, promoted higher levels of secondary phases in the composite. The flexural bend strength (FBS) showed high values and also significant differences dependent on the amount of glass added. A 2 wt% addition gave a gradual increase in FBS with temperature. With a 4 wt% addition there was an increase in FBS, but above 1300 degrees C there was a rapid decrease. These effects were mirrored in the linear shrinkage. Both the linear shrinkage and the FBS results were attributed to both the phase changes occurring and also change in grain size with increasing firing temperature.
将玻璃加入羟基磷灰石（HA）中作为烧结助剂，以改善其机械性能。玻璃的添加量为2 wt%和4 wt%，粉末进行单轴压制。坯体在多种温度（1200、1250、1300和1350℃）下烧结，研究玻璃添加量和烧结温度的影响，以确定它们对烧结过程的作用。结果发现，玻璃促进了一些相变，这与复合材料中添加的玻璃量有关。在1200和1250℃时，发现有一些β-磷酸三钙（TCP），其余为HA。然而，在1300和1350℃时，β-TCP和α-TCP均有形成。如预期的那样，4 wt%的添加量促进了复合材料中更高水平的第二相形成。抗弯强度（FBS）显示出较高的值，并且也因玻璃添加量的不同而有显著差异。添加2 wt%时，FBS随温度逐渐增加。添加4 wt%时，FBS有所增加，但在1300℃以上迅速下降。这些影响在线性收缩中也有体现。线性收缩和FBS结果均归因于发生的相变以及随着烧结温度升高晶粒尺寸的变化。
