Jong Ronald P H, Krzywda Piotr M, Benes Nieck E, Mul Guido
Photocatalytic Synthesis Group, Faculty of Science & Technology of the University of Twente PO Box 217 Enschede The Netherlands
Membrane Science and Technology Cluster, Faculty of Science & Technology of the University of Twente PO Box 217 Enschede The Netherlands.
RSC Adv. 2020 Aug 28;10(53):31901-31908. doi: 10.1039/d0ra04905k. eCollection 2020 Aug 26.
Porous Ti based hollow fibres with extremely low electrical resistivity (4.1-9.6 μΩ m), orders of magnitude smaller than reported for Ti-fibres in the literature, were produced by dry-wet spinning of a mixture of Ti-particles, polyethersulfone (PES), and -methylpyrrolidone (NMP). Utilizing a two-step thermal decomposition of PES, consisting of treatment in air at 475 °C, followed by treatment in argon at 800 °C, hollow fibres of entirely metallic Ti are obtained, as confirmed by XRD, SEM-EDS, and TGA-MS analyses. Only a thin oxide layer is formed due to ambient surface oxidation, as identified by XPS analysis. Carbonization of the polymer under an inert atmosphere can be used to produce a Ti/TiC-composite. To obtain a Ti/TiN composite, the porous Ti-tubes can be treated in nitrogen atmosphere at 800 °C. The porosity, pore size distribution, and bending-strength of the fibres were determined for a low (800 °C) and high (1100 °C) degree of sintering, and it was found that these are largely independent of the chemical surface composition. The presence of TiC or TiN, likely in an outer, but crystalline shell (based on XRD and XPS data), results in lower resistivity than of the pure Ti fibres, which can be attributed to the insulating layer of TiC or TiN preventing capacitive effects at the Ti/air interface. The developed preparation methodology results in porous metallic and composite Ti based fibres, which are very suitable for electrochemical applications.
通过对钛颗粒、聚醚砜（PES）和N-甲基吡咯烷酮（NMP）的混合物进行干湿纺丝，制备出了具有极低电阻率（4.1 - 9.6 μΩ m）的多孔钛基中空纤维，该电阻率比文献中报道的钛纤维小几个数量级。利用聚醚砜的两步热分解，即在475℃空气中处理，然后在800℃氩气中处理，得到了完全由金属钛构成的中空纤维，X射线衍射（XRD）、扫描电子显微镜-能谱分析（SEM-EDS）和热重-质谱分析（TGA-MS）证实了这一点。X射线光电子能谱分析（XPS）表明，由于环境表面氧化，仅形成了一层薄氧化层。在惰性气氛下对聚合物进行碳化可制备Ti/TiC复合材料。为了获得Ti/TiN复合材料，可将多孔钛管在800℃的氮气氛中处理。测定了低（800℃）、高（1100℃）烧结程度下纤维的孔隙率、孔径分布和弯曲强度，发现这些性质在很大程度上与化学表面组成无关。基于XRD和XPS数据，TiC或TiN可能存在于外层但为结晶壳层中，这导致其电阻率低于纯钛纤维，这可归因于TiC或TiN的绝缘层阻止了Ti/空气界面处的电容效应。所开发的制备方法可得到多孔金属和复合钛基纤维，非常适合用于电化学应用。
