表面多孔NiTi-羟基磷灰石/NiTi生物复合材料的制备与性能

利用放电等离子烧结技术制备了表面多孔NiTi-羟基磷灰石(HA)/NiTi生物复合材料,研究了烧结温度对复合材料宏观形貌、微观结构、表面孔隙特征、力学性能及体外生物活性的影响。结果表明:随着烧结温度从800℃提高到950℃,NiTi-HA/NiTi复合材料由复杂的Ti、Ni、Ti_2Ni、Ni_3Ti、HA混合相逐渐转变为单一的NiTi+HA相,内外层界面形成稳定的冶金结合且表面孔隙率与平均孔径呈缓慢减小趋势;同时抗压强度显著提高而弹性模量变化不明显。与传统NiTi、多孔NiTi及多孔NiTi-HA材料相比,950℃温度下制备的NiTi-HA/NiTi复合材料不仅具有良好的界面结合和表面孔隙特征(孔隙率45.6%、平均孔径393μm)、较高的抗压强度(1 301MPa)、较低的弹性模量(10.2GPa)以及优异的超弹性行为(超弹性恢复应变4%)的最佳匹配,而且还具有良好的体外生物活性。

Fabrication and properties of surface porous NiTi-Hydroxyapatite/NiTi biocomposites

Surface porous NiTi-Hydroxyapatite(HA)/NiTi biocomposites were prepared by spark plasma sintering (SPS) technology.The effects of different sintering temperatures on the macroscopic morphology, microstructure, surface pore characteristics, mechanical properties and in vitro biological activity of the composites were investigated.The results show that the NiTi-HA/NiTi biocomposites are consisted of complex Ti, Ni, Ti2Ni, Ni3Ti, HA mixed phase and gradually transformed into a single NiTi+HA phase with increasing of sintering temperatures form 800℃ to 950℃.Furthermore, a stable metallurgical bonding on the internal and external interface of the composites can be observed.Meanwhile, the porosity and average pore size of surface layer are in a slowly decreasing trend.As a result, compressive strength of the composites is significantly increased, but compressive elastic modulus of the composites is changed not obvious.Compared with NiTi, porous NiTi and porous NiTi-HA, NiTi-HA/NiTi biocomposites sintered at 950℃ not only exhibits a best match with better interface bonding, good surface pore characteristics (45.6% porosity as well as 393 μm average pore size), higher compressive strength (1 301 MPa), lower the compressive elastic modulus (10.2 GPa) and excellent superelastic recovery strain (>4%), but also showes a good in vitro biological activity.