Li Feng, Jiang Xiaosong, Shao Zhenyi, Zhu Degui, Luo Zhiping
School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China.
Department of Chemistry and Physics, Fayetteville State University, Fayetteville, NC 28301, USA.
Nanomaterials (Basel). 2018 Sep 15;8(9):729. doi: 10.3390/nano8090729.
Nano-carbon reinforced titanium matrix/hydroxyapatite (HA) biocomposites were successfully prepared by spark plasma sintering (SPS). The microstructure, mechanical properties, biocompatibility, and the relationship between microstructure and properties of biocomposites were systematically investigated. Results showed there are some new phases in sintered composites, such as β-Ti, TiO₃, ZrO₂, etc. Moreover, a small amount of TiP, CaTiO₃, Ca₃(PO₄)₂ were also detected. The reaction that may occur during the preparation process is suppressed to some extent, which is because that the addition of second phases can prevent the direct contact of titanium with HA and reduce the contact areas. Transmission electron microscope (TEM) analysis proved the existence of elemental diffusion and chemical reactions in sintered composites. Compared with results of composites prepared by hot-pressed sintering before, mechanical properties (microhardness, compressive strength, and shear strength) of 0.5-GNFs composites prepared by SPS were increased by about 2.8, 4.8, and 4.1 times, respectively. The better mechanical properties of 0.5-GNFs composite in nano-carbon reinforced composites are mainly due to the lower degree of agglomeration of tubular carbon nanotubes (CNTs) compared to lamellar graphene nanoflakes (GNFs). Moreover, the strengthening and toughening mechanisms of nano-carbon reinforced titanium alloy/HA biocomposite prepared by spark plasma sintering (SPS) mainly included second phase strengthening, grain refinement strengthening, solution strengthening, graphene extraction, carbon nanotubes bridging, crack tail stripping, etc. In addition, in vitro bioactivity test revealed that the addition of nano-carbon was beneficial to promote the adhesion and proliferation of cells on the surface of titanium alloy/HA composite, because nano-carbon can enhance the formation of mineralized necks in the composites after transplantation, stimulate biomineralization and promote bone regeneration.
通过放电等离子体烧结（SPS）成功制备了纳米碳增强钛基/羟基磷灰石（HA）生物复合材料。系统研究了生物复合材料的微观结构、力学性能、生物相容性以及微观结构与性能之间的关系。结果表明，烧结复合材料中存在一些新相，如β-Ti、TiO₃、ZrO₂等。此外，还检测到少量的TiP、CaTiO₃、Ca₃(PO₄)₂。制备过程中可能发生的反应在一定程度上得到了抑制，这是因为第二相的添加可以防止钛与HA直接接触并减小接触面积。透射电子显微镜（TEM）分析证明了烧结复合材料中存在元素扩散和化学反应。与之前热压烧结制备的复合材料结果相比，通过SPS制备的0.5-GNFs复合材料的力学性能（显微硬度、抗压强度和剪切强度）分别提高了约2.8倍、4.8倍和4.1倍。在纳米碳增强复合材料中，0.5-GNFs复合材料具有更好的力学性能，主要是因为与层状石墨烯纳米片（GNFs）相比，管状碳纳米管（CNTs）的团聚程度更低。此外，通过放电等离子体烧结（SPS）制备的纳米碳增强钛合金/HA生物复合材料的强化增韧机制主要包括第二相强化、晶粒细化强化溶液强化、石墨烯析出、碳纳米管桥接、裂纹尾迹剥离等。此外，体外生物活性测试表明，纳米碳的添加有利于促进细胞在钛合金/HA复合材料表面的黏附与增殖，因为纳米碳可以增强移植后复合材料中矿化颈的形成，刺激生物矿化并促进骨再生。
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