Slow crack growth behaviour of hydroxyapatite ceramics
Slow crack growth behaviour of hydroxyapatite ceramics
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DOI：
10.1016/j.biomaterials.2005.03.031
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发表时间：
2005-11-01
期刊：
影响因子：
14
通讯作者：
Fantozzi, G
中科院分区：
文献类型：
--
作者：
Benaqqa, C;Chevalier, J;Fantozzi, G
在医疗应用材料中，羟基磷灰石是骨科最好的候选材料之一，因为它具有类似于骨的矿物部分的成分。用双扭转技术研究了致密羟基磷灰石材料的慢裂纹扩展行为。得到了不同环境和工艺条件下的裂纹率V随应力强度因子K-1的变化规律。氧化物陶瓷中水分子的应力辅助腐蚀通常是导致裂纹缓慢扩展的原因。这里得到的不同传播阶段可以根据这一过程进行分析。还观察到定义安全使用范围的阈值的存在。羟基磷灰石陶瓷似乎对缓慢的裂纹扩展非常敏感，即使在非常低的K-1下也会发生裂纹扩展。这可以用它们含有羟基(HAP：CA-10(PO4)(6)(OH)(2))的事实来解释，这有利于水在裂纹表面的吸附，从而在有水存在的情况下，表面能大大降低。这项研究表明，必须仔细控制工艺条件，特别是烧结温度，这对V-K-1定律起着关键作用。例如，在高于或低于最佳温度50℃的温度下烧结，可能会使V-K-1定律向非常低的应力强度因子移动。最后讨论了时效的影响。(C)2005爱思唯尔有限公司。保留所有权利。
Among materials for medical applications, hydroxyapatite is one of the best candidates in orthopedics, since it exhibits a composition similar to the mineral part of bone. Double torsion technique was here performed to investigate slow crack growth behaviour of dense hydroxyapatite materials. Crack rate, V, versus stress intensity factor, K-1, laws were obtained for different environments and processing conditions. Stress assisted corrosion by water molecules in oxide ceramics is generally responsible for slow crack growth. The different propagation stages obtained here could be analyzed in relation to this process. The presence of a threshold defining a safety range of use was also observed. Hydroxyapatite ceramics appear to be very sensitive to slow crack growth, crack propagation occurring even at very low K-1. This can be explained by the fact that they contain hydroxyl groups (HAP: Ca-10(PO4)(6)(OH)(2)), favouring water adsorption on the crack surface and thus a strong decrease, of surface energy in the presence of water. This study demonstrates that processing conditions must be carefully controlled, specially sintering temperature, which plays a key role on V-K-1 laws. Sintering at 50 degrees C above or below the optimal temperature, for example, may shift the V-K-1 law towards very low stress intensity factors. The influence of ageing is finally discussed. (c) 2005 Elsevier Ltd. All rights reserved.