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从羟基磷灰石的研究现状和多孔生物陶瓷材料的特性入手,分析出羟基磷灰石多孔陶瓷是目前最有应用前景的种植材料,但是在改善羟基磷灰石陶瓷的力学性能方面的研究中,存在增强材料与基体热膨胀系数不匹配、复合材料成孔机理和强度关系不明确以及生物活性受到影响等问题.提出了用天然针状硅灰石增韧多孔羟基磷灰石材料的制备方法. 相似文献
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扫描电镜观察显示胫骨是一种由羟基磷灰石和胶原蛋白组成的生物陶瓷复合材料,其增强相羟基磷灰石平行于骨的表面以层状的形式排列.观察也显示这些羟基磷灰石层又是由许多长而薄的羟基磷灰石片所组成,这些羟基磷灰石片也平行排列,且其厚度具有纳米的尺度.基于在胫骨中观察到的羟基磷灰石片平行纳米结构,建立模型,研究了其最大拔出能.结果表明羟基磷灰石片长而薄的形状以及平行排列方式增加了其最大拔出能,进而提高了骨的断裂韧性. 相似文献
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利用高温固相法合成了掺钇的磷酸四钙,将其与无水磷酸氢钙以物质的量比1∶1混合制备了钇-羟基磷灰石骨水泥(Y-HAC)。结果表明:少量钇的掺入不会改变骨水泥的水化产物,骨水泥能正常水化,水化产物为弱结晶羟基磷灰石。与纯羟基磷灰石骨水泥(HAC)相比,Y-HAC的湿态抗压强度提高了120%,干态抗压强度提高了85%。同时,钇的掺入还提高了材料的孔隙率。Y-HAC的微观结构呈现紧密结合的片状羟基磷灰石结晶体。体外释放实验表明,钇的释放量极低,说明钇-羟基磷灰石骨水泥具有较好的稳定性。Y-HAC是一种很有前途的骨组织修复材料,并可用于载药材料和骨组织工程支架材料。 相似文献
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《功能材料》2015,(19)
采用化学沉淀法通过钛掺杂合成了不同钛掺杂量(0.2%~2.4%(质量分数))的羟基磷灰石纳米粉,研究了钛掺杂量对其烧结稳定性和晶粒尺寸的影响规律。结果表明,不同钛掺杂量对羟基磷灰石的烧结稳定性和晶粒尺寸有非常显著的影响。随着钛掺杂量的增加,羟基磷灰石的晶格结构发生变化,a、c轴尺寸及其晶胞体积都在增加,并且和钛掺杂量成正比。在1 000~1 200℃烧结,不同钛掺杂量羟基磷灰石均未发生分解,表明钛掺杂抑制了羟基磷灰石的高温分解,提高了它的烧结稳定性。同时,钛掺杂有效限制了烧结过程中羟基磷灰石晶粒的长大,0.8%(质量分数)钛掺杂羟基磷灰石晶粒尺寸较纯羟基磷灰石晶粒尺寸明显细化。 相似文献
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将纳米羟基磷灰石,硅橡胶复合材料浸泡于模拟体液(SBF)中仿生合成了磷酸钙,利用IR、XRD、ICP和SEM等测试手段对表面沉积物进行表征.结果表明:在模拟体液中浸泡后,复合材料表面形成了分布均匀的以羟基磷灰石为主要成分的晶粒,表面羟基磷灰石的比例得到提高,生物学性能得以进一步改善;表明纳米羟基磷灰石,硅橡胶复合材料是一种生物活性材料. 相似文献
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纳米羟基磷灰石/聚酰胺66仿生复合材料的非等温结晶动力学研究 总被引:2,自引:0,他引:2
用差示扫描量热仪(DSC)研究了不同比例的纳米羟基磷灰石(nano hydroxyapatite, n HA)/聚酰胺66(polyamide 66,PA66)仿生复合材料的非等温结晶行为。结果表明:(1)纳米羟基磷灰石的加入,起到了异相成核剂的作用,提高了PA66 的结晶速率,且结晶速率随纳米羟基磷灰石的含量的增加而增加,纯PA66的结晶度则随着纳米羟基磷灰石的增加而降低。(2)PA66 和复合材料的结晶峰都随降温速率的增加从高温向低温方向移动,且结晶峰变宽。(3)以Mo法进行非等温结晶数据处理,得到的F(T) 随结晶度的增加而增加,a值却几乎不随结晶度变化,表明降温速率越快,单位结晶时间达到的结晶度越高,但各降温速率下的结晶方式基本相同。 相似文献
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生物羟基磷灰石的合成 总被引:1,自引:0,他引:1
综述了生物羟基磷灰石合成研究的最新进展,重点介绍和评述了羟基磷灰石的合成与制备方法,讨论了各种方法的特点和应用前景。最新的研究动态表明,羟基磷灰石研究从基本的化学反应合成向生物矿化与新生骨引导机理及硬组织再造技术方向发展。同时,羟基磷灰石在金属、陶瓷等植入体表面的涂层、以及天然材料制备羟基磷灰石依然是其合成研究的主要方向。 相似文献
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Toughness is crucial to the structural function of bone. Usually, the toughness of a material is not just determined by its composition, but by the ability of its microstructure to dissipate deformation energy without propagation of the crack. Polymers are often able to dissipate energy by viscoplastic flow or the formation of non-connected microcracks. In ceramics, well-known toughening mechanisms are based on crack ligament bridging and crack deflection. Interestingly, all these phenomena were identified in bone, which is a composite of a fibrous polymer (collagen) and ceramic nanoparticles (carbonated hydroxyapatite). Here, we use controlled crack-extension experiments to explain the influence of fibre orientation on steering the various toughening mechanisms. We find that the fracture energy changes by two orders of magnitude depending on the collagen orientation, and the angle between collagen and crack propagation direction is decisive in switching between different toughening mechanisms. 相似文献
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A new concept consisting of binding and ex situ toughening is proposed for manufacturing and toughening of textile reinforced pCBT composites. The present study assesses the influence of various preforming binders on interlaminar fracture properties. Interlaminar fracture toughness of textile reinforced pCBT composites was investigated under mode I and mode II deformation. A standard double cantilever beam (DCB) test and an end notched flexure (ENF) test based on a three-point bending test were applied to evaluate the interlaminar fracture toughness in mode I and mode II, respectively. The effect of binder type, filling content and preparation concept on fracture properties under the mentioned two deformation modes were discussed on the basis of morphology analysis of fracture sections with scanning electric microscopy. Flexural properties of the textile reinforced pCBT laminates prepared using the selected preforming binder were characterized for further verification of the performance of the proposed concept. 相似文献
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Gautier S Champion E Bernache-Assollant D 《Journal of materials science. Materials in medicine》1999,10(9):533-540
Fracture toughness of Al2O3 platelet-reinforced hydroxyapatite (HAP) ceramics was investigated using the Vickers' indentation technique. The geometrical anisotropy of alumina platelets induces an anisotropic toughening. The efficiency of reinforcing mechanisms remains maximum for a crack propagating with an angular deviation inferior to 30° around the direction perpendicular to alumina disc faces. This is assumed to result from a crack deflection mechanism which induces a favorable contribution of mode II failure. A small effect of hydroxyapatite grain size becomes noticeable in the direction parallel to alumina disc faces. The toughening depends on the size and volume content of alumina platelets. Large size platelets provoke a spontaneous microcracking of the HAP matrix which is detrimental to the mechanical reliability, whereas small platelets lead to a strong toughening. The results relate to the intensity of thermoelastic residual stresses within the matrix around alumina inclusions. © 1999 Kluwer Academic Publishers 相似文献
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Preparation and characterization of bioactive monolayer and functionally graded coatings 总被引:1,自引:0,他引:1
Wang M Yang XY Khor KA Wang Y 《Journal of materials science. Materials in medicine》1999,10(5):269-273
Hydroxyapatite powders were made by reacting orthophosphoric acid with calcium hydroxide and dense bioactive coatings were subsequently produced by the plasma spray technique. Three types of hydroxyapatite (flame spheroidized) monolayer coatings and three types of functionally graded coatings were manufactured. It was found that average microhardness values of monolayer coatings decreased as the indentation load increased. The relationship between indentation load and indent diagonal length observed Meyer's law. Microhardness and fracture toughness of coatings were affected by characteristics of feedstock powders for plasma spraying. The indentation fracture toughness of coatings could be significantly increased by incorporating a toughening phase. ©1999 Kluwer Academic Publishers 相似文献
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Takayuki Kusaka Keiko Watanabe Masaki Hojo Toshiyasu Fukuoka Masayasu Ishibashi 《Composites Science and Technology》2009
The mode II interlaminar fracture behavior and the toughening mechanism of Zanchor reinforced composite laminates were investigated by using the End Notched Flexure (ENF) and Interlaminar Shear (ILS) specimens. The ENF test results demonstrated that the Zanchor process was highly effective to improve the mode II fracture toughness of composite laminates, where the fracture toughness increased almost linearly with the Zanchor density. The R-curves of Zanchor composites were roughly divided into the transition and stable regions, where the width of the transition region became larger as the Zanchor density increased. The macroscopic fracture behavior of the Zanchor composites was still brittle under mode II loading like that of the base composite, where the crack tip process zone was estimated to be rather small regardless of the Zanchor density. The ILS test results demonstrated that the square of the normalized shear strength increased linearly with the Zanchor density and agreed quantitatively with the normalized fracture toughness. The wedge effect was supposed to be the dominant toughening mechanism against the mode II fracture, where the entangled fiber bundles partly sustained the shear stress in the vicinity of the crack tip. The entangled fiber bundles played an important role to form the mode II fracture surface, where the microscopic fracture pattern of the entangled fiber bundles was mainly the breakage of the fiber bundles rather than the pull-out or debonding of the fiber bundles. 相似文献
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从复合材料离位增韧思想出发,选用具有高孔隙率的尼龙无纺布(PNF)作为结构化增韧层,采用RTM工艺制备了PNF层间增韧改性的U3160碳纤维增强环氧3266树脂基复合材料(U3160-PNF/3266),并研究了其韧性相关性能和增韧机制。结果表明:U3160-PNF/3266复合材料层间仍保持其原有的结构形式,同时与层间树脂相互贯穿形成了一种非反应诱导相分离的双连续结构,并且这种双连续结构表现出显著的增韧效果。U3160-PNF/3266复合材料的Ⅰ型层间断裂韧性和Ⅱ型层间断裂韧性分别提高了1.1倍和1.4倍,冲击后压缩强度由212MPa提高到281MPa。 相似文献
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采用溶剂法和热熔法制备了不同有机黏土质量分数的有机黏土/聚醚砜(PES)-环氧复合材料,通过对其微观形态和力学性能的研究,揭示了复合材料的增韧机制。在有机黏土/PES-环氧复合材料中添加T800H(12K)碳纤维,制备了T800H-有机黏土/PES-环氧复合材料预浸料单向带,采用热压罐工艺制备了复合材料单向板,对其I型、II型层间断裂韧性进行了研究。结果表明:T800H-有机黏土/PES-环氧复合材料的层间断裂韧性随有机黏土质量分数变化趋势与有机黏土/PES-环氧复合材料的断裂韧性趋势一致,证明了增韧机制的正确性。 相似文献
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采用动态焦散线实验系统,对有机玻璃(PMMA)在冲击载荷下的I型和I-II混合型裂纹在起裂和扩展时的动态断裂特性进行了研究。结果表明:随着PMMA由I型断裂转变为I-II混合型断裂,从落锤作用在试件上到裂纹起裂所需时间不断增加,说明裂纹起裂需要的能量有所增加,同时从裂纹起裂到最终贯通所需时间不断减少,说明裂纹平均扩展速度也不断增大;在I型断裂中,PMMA的断裂韧度KIC为2.04 MN/m3/2,而在I-II混合型断裂中,PMMA的断裂韧度KIC低于I型断裂时的断裂韧度KIC,但是KIIC有所增大;对于I-II混合型断裂,PMMA极限扩展速度约为366m/s,当达到极限扩展速度后,裂纹尖端出现微裂纹增韧现象,使裂纹的表面能迅速增大,随后裂纹的扩展速度迅速减小。 相似文献
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20%纳米ZrO2(3Y)粉末加入到高纯亚微米Al2O3粉中,采用高压干压成型方法和恒速升温多阶段短保温烧结方法制备出不同烧结温度下的复相陶瓷。研究烧结温度对复相陶瓷力学性能的影响,通过XRD,EDS和SEM对复相陶瓷进行元素组成和微观结构分析。结果表明:烧结温度在很大程度上影响着复相陶瓷的力学性能和微观结构,常压烧结1600℃保温8h时,相对密度、维氏硬度和断裂韧性达到最大,分别为98.6%,18.54GPa和9.3MPa·m1/2,而基体晶粒尺寸为1.4~8.1μm,ZrO2相变量为34.6%。1600℃下复相陶瓷具有优质的微观结构,断裂方式为沿晶-穿晶混合断裂模式。ZrO2(3Y)粉体的加入,从相变增韧、内晶型颗粒增韧和裂纹偏转等多个方面提高了复相陶瓷的断裂韧性。 相似文献