骨组织工程用镁基泡沫生物材料的制备与其体外降解行为（英文）

采用熔体发泡法制备了一种镁基泡沫生物材料,其中以镁钙合金为基体材料,羟基磷灰石(HA)为增粘剂,碳酸镁(Mg CO3)为发泡剂。对结构均匀的镁基泡沫生物材料进行测试,研究其生物可降解行为。用腐蚀前后的孔结构、浸泡试验和电化学测试对镁基泡沫材料的生物可降解性进行表征。结果表明,在固定时间内随着试样孔隙率的增加,失重率不断增加;相比于添加了HA的样品,不含HA颗粒的样品呈现出更高的质量损失率。同时,Mg基泡沫生物材料的总孔隙率和HA含量均对Mg基泡沫材料的开孔率有重要的影响。在相同时间内,开孔率随试样总孔隙率的增加而增加。在模拟体液(SBF)介质中,含有HA的Mg基泡沫生物材料比不添加HA的试样具有更高的耐腐蚀性。     

粉末冶金制备TNZS基生物材料的体外组织相容性

采用高能球磨与冷压烧结相结合的粉末冶金法制备了TNZS、5%TiO_2/TNZS及5%HA/TNZS(质量分数,下同)生物材料,并研究了TiO_2和HA的添加对TNZS体外组织相容性的影响。结束表明:3种TNZS基生物材料均无细胞毒性;5%TiO_2/TNZS和5%HA/TNZS表面在1,3,5和7 d的细胞相对增殖抑制率CPIR值大幅低于TNZS组,TiO_2和HA的添加显著提高了TNZS材料表面的细胞增殖速度,增强了其细胞增殖能力,更有助于诱导成骨细胞的体外增殖;3种TNZS基材料表面贴附的成骨细胞伪足伸展状态良好,而5%TiO_2/TNZS表面贴附的成骨细胞分布更加均匀。     

生物可降解羟基磷灰石颗粒增强镁基复合材料的制备及表征(英文)

采用粉末冶金方法制备了生物可降解的纯镁基体和不同百分含量的羟基磷灰石颗粒增强镁基复合材料。通过压缩试验和电化学测试对复合材料的机械性能和耐腐蚀性能进行了研究。结果表明,复合材料的压缩屈服强度明显高于纯镁基体,并且随着羟基磷灰石含量的增加而提高;电化学测试结果表明,复合材料在生物模拟体液中的腐蚀电位与纯镁基体相比明显提高,其中Mg-20%HA复合材料的腐蚀电位为-1.582 V,腐蚀电流密度为10.84μA/cm2。     

非对称HA/316L不锈钢梯度生物材料的制备与表征

采用干粉铺叠法和热压工艺制备了非对称HA/316L不锈钢功能梯度生物材料,并测定了其相对密度和抗弯强度,采用X射线衍射仪、扫描电镜、金相显微分析技术等对材料进行了物相和显微组织分析.结果表明:非对称HA-316L不锈钢生物FGM在宏观上呈现明显的梯度分布,微观上则各成分分布连续、均匀,各梯度层之间没有明显的宏观界面,界面结合紧密;随着316L不锈钢含量的增大,材料的相对密度增加,抗弯强度提高,平均抗弯强度达450 MPa左右,体现出FGM的热应力缓和行为;此外,在生物FGM中,HA和316L不锈钢两相在热压过程中发生了不同程度的固溶,表明HA和316L不锈钢能够形成好的结合.     

粉末冶金制备非连续增强MB15镁基复合材料时效行为的研究

研究了SiC颗粒和钛合金(TC4)颗粒对MB15镁合金145C时效硬化行为的影响以及SiCp／MB15和TC4p／MB15复合材料的室温拉伸性能随时效时间的变化规律。结果表明，增强颗粒的加入加速了MB15的时效速度，但并未改变其时效硬化的基本规律：MB15及其复合材料的时效硬化曲线上均存在双峰现象；两种复合材料抗拉强度和屈服强度的峰值与其较高的硬度峰值基本对应。     

颗粒增强镁基复合材料的制备工艺研究进展

综述了颗粒增强镁基复合材料的主要制备工艺和研究进展,重点介绍了粉末冶金法、搅拌铸造法和原位反应自生增强法等制备方法,并阐述了各种制备方法的特点和存在的问题。对颗粒增强镁基复合材料制备工艺的发展提出了自己的看法,指出半固态搅拌法是最适宜工业化生产的制备工艺,原位反应自生增强法是最具研究前景和发展潜力的制备工艺。     

镁基储氢材料的研究进展

对近几十年来镁基储氢材料的研究历史做了简单的回顾 ,并对镁基储氢材料进行了合理的分类 ,将其分为镁基合金材料体系和镁基复合材料体系 ;分别对合金材料和复合材料的储氢性能进行了系统的阐述 ,指出现有的技术手段已经能够制备具有优异充放氢性能的镁基储氢材料。对镁基储氢材料的应用现状进行了综述 ,总结了现有的镁基储氢材料储氢器以及镁基储氢材料电化学性能的研究现状 ,指出了今后镁基储氢材料应用研究的重点     

原位颗粒增强镁基复合材料的制备

综述了原位颗粒增强镁基复合材料的研究进展，重点介绍了原住反应法制备颗粒增强镁基复合材料的基本原理和过程，并分析了其组织和性能；同时还简述了传统铸造法制备原位颗粒增强镁基复合材料的特点。最后，对原位颗粒增强镁基复合材料的发展趋势作了展望。     

表面涂覆含氟羟基磷灰石和缺钙羟基磷灰石的镁合金体外降解行为(英文)

通过电化学沉积方法,在生物降解镁合金表面覆盖含氟羟基磷灰石(FHA)涂层和缺钙羟基磷灰石(CDHA)涂层。采用X射线衍射、傅立叶变换红外光谱、透射电子显微镜、扫描电子显微镜和能量色散X射线光谱研究涂层特性。结果表明:涂覆纳米FHA涂层的样品具有垂直于样品表面的纳米针状结构,比涂覆CDHA涂层样品的结构更致密和更均匀。纳米FHA涂层比纳米CDHA涂层具有更小的晶粒尺寸,分别为65 nm和95 nm。然而,CDHA涂层比FHA涂层更厚,厚度分别为19μm和15μm。通过极化、浸泡和析氢实验研究的腐蚀行为表明:纳米FHA涂层和纳米CDHA涂层显著降低腐蚀速率并引起钝化。纳米FHA和纳米CDHA涂层可以加速骨状磷灰石层的形成,相比未覆盖的镁合金可以显著减少溶出速率。纳米FHA涂层能对镁合金提供有效的防护并具有更高的腐蚀性能。因此,覆盖纳米FHA涂层的镁合金在整形外科领域具有良好的应用前景。     

粉末冶金制备TNZS基生物材料的组织与弹性模量

采用高能球磨48h制备Ti-24Nb-4Zr-7.9Sn(TNZS)、5wt.%TiO2/TNZS及5wt.%HA/ TNZS混合粉末并进行冷压烧结,研究了三种混合粉末的形貌、物相以及冷压烧结后三种TNZS基生物材料的组织、成分、相组成、孔隙特征及弹性模量。高能球磨48h的三种混合粉末都发生机械合金化;烧结后TNZS相组成为α-Ti和β-Ti,TiO₂/TNZS相组成为α-Ti、β-Ti、金红石TiO₂和锐钛矿TiO₂,HA/TNZS相组成除α-Ti、β-Ti、HA外,还有Ti₂O、CaTiO₃、CaO和Ti_xP_y新相生成;三者孔隙率分别为2.466%、5.030%和13.027%;三者弹性模量分别为64.00 GPa、103.93 GPa和119.43 GPa。     

Comparison of the in vitro corrosion behavior of biodegradable pure Zn in SBF, 0.9% NaCl,and DMEM

Zn-based alloys are considered to be the new biodegradable implant materials due to their suitable degradation rate and good biocompatibility. The biocorrosion behavior of pure Zn in 0.9% NaCl, simulated body fluid, and Dulbecco's modified Eagle's medium (DMEM) was investigated by electrochemical and immersion tests. These tests revealed that pure Zn has the lowest corrosion rate in DMEM and the highest in 0.9% NaCl. Aggressive Cl⁻ has an important effect on the corrosion process. Buffering agents, amino acids, and glucose have a close connection with corrosion resistance. Among the three solutions, DMEM with a similar ion concentration and necessary nutriments is recommended as the more suitable choice for estimating biodegradable alloys' in vitro degradation.     

镁基大块非晶合金在过冷液相区流变行为本构关系

研究了Mg60Cu30Y10大块非晶合金在过冷液相区的流变行为.结果表明:随着温度升高和应变速率增加,平衡态的牛顿流转变为非平衡态的非牛顿流;其流变行为对于温度和应变速率非常敏感.由粘度与应变速率的关系,根据Arrhenius型VFT方程,确定了流动应力、应变速率和温度的关系.Mg60Cu30Y10大块非晶合金在过冷液相区的流变性能依赖于温度与变形速率,其微观机制可由自由体积模型解释,为大块非晶合金流变成形工艺的实现提供理论依据:温度高于玻璃转变温度以后,自由体积的增加使非晶合金变形过程中能够移动的原子数目随之增加,自由体积周围的原子沿外力的作用方向移动,即宏观上的塑性流变行为.应变速率增加,由热激活引起的自由体积增加不能满足更多原子流变所需的空间体积,导致牛顿流向非牛顿流转变.     

热处理对挤压态Mg-2.7Nd-0.2Zn-0.4Zr合金组织、力学性能和体外降解行为的影响(英文)

设计了Mg-2.7Nd-0.2Zn-0.4Zr(质量分数,%)镁合金作为可降解生物医用材料。对固溶处理后的铸锭进行了热挤压处理,然后对挤压棒分别进行了时效处理、固溶处理及固溶+时效处理。利用光学显微镜和扫描电镜观察了合金的组织,测试了合金的室温力学性能,采用析氢和失重法测试了合金在模拟体液中的降解行为,用扫描电镜观察了降解产物形貌及洗去降解产物后的形貌。结果表明:固溶处理后合金的晶粒明显长大,固溶处理显著提高挤压态合金的伸长率,但降低了合金的强度,而时效处理可提高合金的强度,降低合金的伸长率;热处理可降低合金的屈强比。体外降解实验结果表明:固溶处理使合金的降解速率稍微加快,而时效处理则能稍微减慢合金的降解速率。     

Corrosion behavior of engineering alloys in synthetic wastewater

The corrosion behavior of 1018, 410, and 800 steels exposed to synthetic wastewater have been studied using linear polarization resistance, cyclic potentiodynamic curves (CPCs), electrochemical noise (EN), and electrochemical impedance spectroscopy (EIS) tests. The conditions were: a biochemical oxygen demand of 776 ppm; a chemical oxygen demand of 1293 ppm; a pH of 8; and a cell temperature of 25 °C. From the CPC and EN results, no localized corrosion was found for the stainless steels. However, small indications of a possible localized corrosion process were detected for the 1018 steel. The EIS results revealed that different corrosion mechanisms occurred in the carbon steel compared with the stainless steels. The results show that the corrosion mechanism strongly depends on the type of steel. Overall, the 1018 steel exhibited the highest corrosion rate, followed by the 410 alloy. The highest corrosion resistance was achieved by the 800 alloy. In addition, scanning electron microscopy analyses were carried out to explain the experimental findings.     

A comparative study on the corrosion behavior of NdFeB magnets in different electrolyte solutions

Sintered NdFeB magnets possess excellent magnetic properties. However, the corrosion resistance property of NdFeB is very poor due to its multiphase microstructure consisting of matrix phase Nd₂Fe₁₄B, Nd‐rich phase, and B‐rich phase. The corrosion behavior of NdFeB magnets in sodium hydroxide (NaOH), sodium chloride (NaCl), nitric acid (HNO₃), and oxalic acid (H₂C₂O₄) solutions was investigated by immersion and electrochemical tests. HNO₃is the strongest corrosive electrolyte compared with the other three solutions. The increase in HNO₃concentration can accelerate the corrosion of NdFeB magnets. NaCl belongs to medium corrosion electrolyte. A NaCl concentration of 0.5 M shows the severest corrosive feature in comparison with other concentrations of NaCl solution. NdFeB hardly suffers corrosion in NaOH and H₂C₂O₄solutions owing to the formation of passivation films on the surface of magnets. Based on the corrosion behavior of NdFeB in different electrolytes, the possible corrosion mechanisms are discussed.     

Electrochemical evaluation of Ti‐13Nb‐13Zr,Ti‐6Al‐4V and Ti‐6Al‐7Nb alloys for biomedical application by long‐term immersion tests

In this investigation the electrochemical behaviour of the Ti‐13Nb‐13Zr, Ti‐6Al‐4V and Ti‐6Al‐7Nb alloys, for application as implant materials was evaluated in Hanks' solution by electrochemical techniques. The alloys were immersed in this solution for 410 days and periodically they were tested by electrochemical impedance spectroscopy. At the end of this period, polarization curves of the three titanium alloys were obtained. The electrochemical impedance experimental results were interpreted using an equivalent electrical circuit that simulates a duplex structure oxide composed of an inner compact layer, here called barrier layer, and an outer and porous layer. The results indicated that all the alloys present a very high corrosion resistance in the electrolyte used, typical of passive alloys, and that the corrosion resistance is mainly due to the barrier layer. The passive like behaviour was maintained during the whole period of test.     

Production and fluoride treatment of Mg-Ca-Zn-Co alloy foam for tissue engineering applications

Highly porous Mg-Ca-Zn-Co alloy scaffolds for tissue engineering applications were produced by powder metallurgy based space holder-water leaching method. Mg-Ca-Zn-Co alloy foam can be used as a scaffold material in tissue engineering. Carbamide was used as a space holder material. Fluoride conversion coating was synthesized on the alloy by immersion treatment in hydrofluoric acid (HF). Increasing Zn content of the alloy increased the elastic modulus. Ca addition prevented the oxidation of the specimens during sintering. Electrochemical corrosion behaviour of the specimens was examined in simulated body fluid. Corrosion rate decreased with Zn addition from 1.0% up to 3.0% (mass fraction) and then increased. Mass loss of the specimens initially decreased with Zn addition up to about 3% and then increased. Fluoride conversion coating increased the corrosion resistance of the specimens.     

实海浸泡条件下聚氨酯涂层的失效行为

目的 在青岛市小麦岛试验站开展实海浸泡试验,探究聚氨酯涂层在实际服役过程中的失效行为。 方法 选用TS55?80聚氨酯涂层/Q235碳钢体系为试验样品,开展实海浸泡试验。从聚氨酯涂层的表面形貌、失光率、色差、涂层附着力、化学结构及涂层热稳定性等角度对聚氨酯涂层的失效行为进行研究。结果 在实海浸泡条件下,聚氨酯涂层表面会出现明显的鼓泡和裂纹等缺陷,在浸泡6个月后的涂层表面可以观察到明显的腐蚀产物。随着浸泡时间的延长,涂层的化学结构发生了明显变化,涂层的热稳定性显著降低。在浸泡12个月后,聚氨酯涂层的失光率为69.9%,属于严重失光;涂层的色差达到3.20,属于轻微变色,涂层的附着力降至0.82 MPa,涂层与金属基体的结合强度大幅下降;聚氨酯涂层的阻抗值降至2.81×10³ Ω.cm²,说明涂层的防护性能基本丧失。结论 在实海浸泡条件下,聚氨酯涂层中颜料颗粒的脱落会造成涂层表面孔隙数量的增加,这会加速海水中水和氧气等腐蚀性介质的渗透过程,使得涂层/金属界面处的电化学反应快速进行,导致涂层的防护性能快速下降。此外,聚氨酯链中氨基甲酸酯键的水解是造成聚氨酯涂层发生降解的主要原因。     

高强铝合金循环盐雾加速腐蚀行为与机理研究

目的 研究2A12铝合金在室内模拟及强化腐蚀环境下的腐蚀行为与机理,建立快速评价铝合金腐蚀寿命的加速试验方法。方法 利用设计的室内加速腐蚀环境试验谱,通过实施模拟海洋大气环境效应的循环盐雾加速腐蚀试验,采用外观检查、SEM、XRD及电化学测试等手段,表征了暴露不同周期样品的腐蚀失重、腐蚀形貌、腐蚀产物成分、极化曲线及阻抗谱等腐蚀性能,分析和归纳了铝合金的加速腐蚀行为与机理。结果 随着腐蚀暴露时间的延长,2A12样品腐蚀失重动力学符合幂函数规律且关系式为D=1.662t^1.061,腐蚀速率呈现短暂降低后迅速增加再逐步下降的变化趋势;腐蚀形貌从腐蚀产物均匀分布到逐渐变得集中和突出表面,后期局部出现脱落,腐蚀产物成分均以Al2O3为主,与腐蚀机理分析的化学反应过程基本一致。极化曲线Tafel拟合结果表明,腐蚀电位整体呈现稳定并缓慢减小的变化趋势(?0.509~ ?0.392 V),腐蚀电流密度呈现先波动增加后减小的变化趋势(0.271~0.882 A/cm²);阻抗谱均在高频区表现为1个容抗弧,且容抗弧半径呈现“减小—增大—减小至稳定”的变化趋势;阻抗谱等效电路拟合结果表明,腐蚀产物膜电阻Rf呈现“增大—减小—增大—减小”的变化趋势,极化电阻Rp整体呈现先减小后增大的变化趋势。结论 循环盐雾环境对高强铝合金腐蚀的加速效果显著,从腐蚀动力学、腐蚀产物形貌及成分、电化学特性等角度,能够比较全面地表征铝合金的加速腐蚀行为与机理,为进一步研究加速腐蚀试验的模拟性和相关性提供条件。