水热温度对玻璃纤维增强HAp-CS涂层的影响

为了制备出结合强度较好的生物涂层,采用水热电泳法在碳/碳复合材料表面成功制备了玻璃微纤维增强的羟基磷灰石——壳聚糖(g(f)/HAp-CS)复合涂层,用x-射线衍射仪、透射电子显微镜、扫描电子显微镜、能谱分析仪、红外傅里叶变换分析仪等测试手段对涂层进行了测试和表征,主要研究了水热沉积温度对复合涂层中HAp晶相和涂层显微结构的影响以及HAp涂层的沉积动力学.结果表明:采用玻璃微纤维增强的HAp-CS涂层,致密性和均匀性有了很大提高,显著减少了复合涂层表面的裂纹;随着水热温度的升高,涂层中HAp的衍射峰逐渐增强,表面形貌得到了有效改善,涂层的致密性和均匀性显著提高;涂层的沉积速率随水热温度的升高而加快,其沉积活化能为14.63kJ/mol.     

温度对C/C复合材料表面HAp涂层的影响

采用水热电沉积法在碳／碳（C／C）复合材料表面制备了羟基磷灰石（HAp）涂层，用XRD、SEM等测试手段对涂层进行表征，重点研究了水热温度对HAp涂层晶相和显微结构的影响以及HAp涂层的沉积动力学机理。结果表明：随着温度的升高，HAp衍射峰有所增强，结晶程度变好，涂层更加致密和均匀；涂层的沉积速率随着温度的升高而增加，涂层的沉积活化能为25．89kJ／mol。     

沉积温度对C-AlPO_4涂层显微结构的影响

采用水热电泳沉积法在C/C-SiC基体表面制备了方石英型磷酸铝(C-AlPO4)外涂层,借助XRD和SEM对涂层的晶相组成和显微结构进行了表征。研究了沉积温度对C-AlPO4涂层显微结构的影响,讨论了涂层的沉积动力学,进行了抗氧化性能测试。结果表明:353~393 K范围内,沉积温度对涂层的显微结构有较大影响;涂层的沉积量随着温度的升高而增加;涂层的沉积规律受C-AlPO4带电颗粒的向阴极表面扩散迁移所控制;涂层的沉积活化能为21.88kJ/mol;在1 773 K空气气氛氧化37 h后,涂层试样失重仅为0.53%。     

水热电泳沉积法制备硅酸钇涂层

以声化学法合成的纳米硅酸钇粉体为原料,异丙醇为溶剂,碘为荷电介质,采用水热电泳沉积方法在SiC-C/C复合材料表面制备出硅酸钇涂层,借助XRD和SEM对涂层的晶相组成、表面和断面的微结构形貌进行了表征,重点研究了水热电泳沉积温度对涂层结构及抗氧化性能的影响.结果表明,涂层中以Y2Si2O7为主晶相,涂层的厚度和致密性随着水热温度的增加而提高;与包埋法制备的SiC涂层相比,水热电泳沉积制备的硅酸钇复相涂层具有更好的抗氧化性能,涂层试样在1 500℃的空气气氛下氧化35 h后失重为0.32×10-3 g/cm3.     

生物医用碳/碳复合材料碳化硅涂层的研究

通过包埋法在医用碳／碳复合材料表面制备了碳化硅涂层，采用XRD、SEM、EDS等研究了碳化硅涂层形貌结构，并用MTT法对其进行细胞毒性评价，实验证实该工艺下碳化硅层表面疏松粗糙，具有多孔结构，硅成分成梯度变化，且细胞毒性评价表明该涂层无毒性，这些结果为后续进一步施加生物活性陶瓷涂层提供了实验依据。     

石墨烯/碳复合气凝胶的制备及其吸附性能

碳气凝胶具有高比表面积、高导电性等优异的性能,将碳气凝胶与具有同样优异性能的石墨烯相结合,通过溶胶-凝胶法制备得到石墨烯/碳(G/C)复合气凝胶,进一步提高其吸附性能.研究结果表明,G/C复合气凝胶为三维多孔结构,具有较高的比表面积643 m2/g、孔容积1.688 cm3/g、平均孔径13.50 nm.对水中模拟污染...     

碳/碳复合材料表面等离子喷涂高温抗氧化涂层研究进展

氧化敏感性是限制碳/碳(C/C)复合材料作为超高温结构材料应用于航空航天领域的关键瓶颈。表面涂层技术是目前在高温含氧环境下有望实现C/C复合材料长时稳定服役的最有效手段。其中,广泛应用于制备航空发动机热防护涂层的等离子喷涂技术备受关注。从C/C复合材料表面等离子喷涂高温抗氧化涂层体系出发,综述了硼化物、硅化物和氧化物基抗氧化涂层的国内外研究进展,基于不同喷涂工艺、成分/结构设计和测试环境下的防护性能进行了对比总结,并对后续该方向研究提出了展望。     

H-TiO2/g-C3N4的制备及光催化降解性能研究

为有效缓解我国水资源短缺问题,将水热辅助液相沉积法制备的二氧化钛(H-TiO2)与石墨相氮化碳(g-C3 N4)进行复合,从而有效提高H-TiO2的光催化降解效率.以g-C3 N4的添加量为单一变量,采用水热辅助液相沉积法制备H-TiO2/g-C3 N4复合光催化剂.通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)和氮气吸附-脱附仪对样品进行分析,研究g-C3 N4的添加量对H-TiO2的物相、微观形貌、比表面积和光催化效率的影响.结果表明,g-C3 N4的引入对H-TiO2的微观形貌和光催化降解性能均有显著影响.制备过程中g-C3 N4的存在影响H-TiO2的晶体生长,使得H-TiO2颗粒直径增加,表面粗糙度降低.当g-C3 N4添加量为300 mg时,复合光催化剂(H-T-CN-300)反应速率最高,其在300 W氙灯照射条件下对罗丹明B(RhB)的降解率速率为H-TiO2降解速率的2.8倍.     

碳/碳生物活性玻璃涂层复合材料的组织结构研究

通过包埋－粉末涂刷高温烧结工艺，以碳化硅作为过渡层制备出C／C生物活性玻璃涂层复合材料。采用SEM、EDS、XRD考察了涂层的组织结构，结果表明所制涂层具有多孔结构，从基体到生物活性玻璃涂层，成分和结构呈连续变化，消除了生物玻璃与基体的性质差异，实现了在C／C复合材料表面进行生物活性改性。     

等离子体化学气相沉积制备氮化碳薄膜

以H2、N2和CH4气体为前驱气体,通过等离子体化学气相沉积技术制备氮化碳薄膜。采用场发射扫描电子显微镜(FS-EM)及其附带的能量分散电子谱(EDS)、X射线衍射分析(XRD)、红外光谱(FTIR)和拉曼光谱(Raman)对其结构、表面形貌、元素含量和成键状况进行了分析,并讨论了气体流量比和放电功率对薄膜制备的影响。实验结果表明:沉积的薄膜中含有晶态的C3N4,碳氮原子比接近于理论值0.75,样品中碳氮原子多以C N、C N的形式存在;样品中氮元素的含量随着反应气体中N2含量的增加而增加;放电功率的增大使薄膜的沉积速率增大。     

Influence of deposition voltage on phase, microstructure and antioxidation property of cristobalite aluminum phosphate coatings

Cristobalite aluminum phosphate (C-AlPO4) coatings were prepared by a hydrothermal electrophoretic deposition process on SiC-coated C/C composites. Phase compositions and microstructures of the as-prepared coatings were characterized by XRD and SEM analyses. The influence of deposition voltage on the phase, microstructure and antioxidation property of the cristobalite aluminum phosphate coatings was investigated. Results show that the as-prepared coatings are composed of cristobalite aluminum phosphate crystallites. The thickness and density of cristobalite aluminum phosphate coatings are improved with the increase of deposition voltage. The deposition amount and bonding strength of the cristobalite aluminum phosphate coatings also increase with the increase of deposition voltage. The deposition mass per unit area of the coatings and the square root of the deposition time at different hydrothermal voltages satisfy linear relationship. The antioxidation property of the coated C/C composites is improved with the increase of deposition voltage. Compared with SiC coatings prepared by pack cementation, the multilayer coatings prepared by pack cementation with a later hydrothermal electrophoretic deposition process exhibit better antioxidation property. The as-prepared multi-coatings can effectively protect C/C composites from oxidation in air at 1 773 K for 37 h with a mass loss rate of 0.53%.     

Influence of deposition voltage on phase, microstructure and antioxidation property of cristobalite aluminum phosphate coatings

Cristobalite aluminum phosphate (C-AlPO₄) coatings were prepared by a hydrothermal electrophoretic deposition process on SiC-coated C/C composites. Phase compositions and microstructures of the as-prepared coatings were characterized by XRD and SEM analyses. The influence of deposition voltage on the phase, microstructure and antioxidation property of the cristobalite aluminum phosphate coatings was investigated. Results show that the as-prepared coatings are composed of cristobalite aluminum phosphate crystallites. The thickness and density of cristobalite aluminum phosphate coatings are improved with the increase of deposition voltage. The deposition amount and bonding strength of the cristobalite aluminum phosphate coatings also increase with the increase of deposition voltage. The deposition mass per unit area of the coatings and the square root of the deposition time at different hydrothermal voltages satisfy linear relationship. The antioxidation property of the coated C/C composites is improved with the increase of deposition voltage. Compared with SiC coatings prepared by pack cementation, the multilayer coatings prepared by pack cementation with a later hydrothermal electrophoretic deposition process exhibit better antioxidation property. The as-prepared multi-coatings can effectively protect C/C composites from oxidation in air at 1 773 K for 37 h with a mass loss rate of 0.53%.     

碳/碳复合材料防氧化涂层研究新进展

介绍了最近几年我们制备的几种高性能的碳／碳复合材料的氧化保护涂层的结构和高温氧化行为，表明采用包埋和渗透法制备的Si—MoSi2、SiC—MoSi2、Al2O3-莫来石-SiC—Al4SiC4以及Al2O3-莫来石-SiC涂层不仅具有很好的抗热震性能，而且能够将碳／碳复合材料的高温氧化保护温度提高到1973K;此外还介绍了一些涂层的失效机理。     

Preparation and self-assembly of chitosan/carbon microsphere composite

Carbon-based films were synthesized by self-assembly of chitosan-encapsulated carbon microsphere (CMS@CS) composite. First, carbon microspheres (CMSs) prepared by chemical vapor deposition were modified by HNO3 and H2O2. Second, oxidized CMSs were modified by chitosan (CS). Finally, CMS@CS was self-assembled by vertical deposition, in which suspension concentration and deposition temperature on the quality of self-assembling film were investigated. Field emission scanning electron microscopy, atomic force microscopy, X-ray diffraction, thermogravimetry, and Fourier transformation infrared spectrometry were employed to characterize the morphology and structure of the samples. The results show that CMSs modified by CS had uniform particle size and good dispersion, CMS@CS was self-assembled into a dense film, the film thickened with increasing suspension concentration at fixed temperature, and more ordered film was obtained at 1 wt% of suspension concentration and 50 ℃. The ultraviolet-visible absorption spectra show that the absorbance of CMS@CS film grew steadily with increasing suspension concentration and that the CMSs with oxygen-containing groups have a good assembling performance to form composite films with CS.     

模拟体液中纳米羟基磷灰石/壳聚糖的制备及表征

从仿生合成的思路出发,分别以模拟体液和含有壳聚糖的模拟体液为反应介质,通过磷酸和硝酸钙反应合成了羟基磷灰石(HAp)和HAp/壳聚糖复合粉体,利用TG-DTA、XRD、FT-IR和TEM等对HAp和HAp/壳聚糖的形成过程、结构及其微观形貌进行了研究.结果表明,在模拟体液中合成的HAp粉体呈现出球状和短棒状形态;HAp/壳聚糖复合粉体呈现出不规则形状,粒度<100 nm,主要晶相为羟基磷灰石.体外生物活性实验结果表明,HAp/壳聚糖复合材料比纯HAp具有更好的生物活性,具有较强的诱导磷灰石沉积能力.     

水热法制备碳纳米纤维与氧化锌复合材料

将静电纺丝技术制备的碳纳米纤维（CNFs）作为衬底材料,利用水热方法,通过改变水热反应温度和反应溶液浓度进行对比实验,得到制备碳纳米纤维（CNFs）与氧化锌（ZnO）复合材料的最佳方法.将获得的产物通过场发射电子扫描显微镜（FE-SEM）和X射线粉末衍射（XRD）检测,结果显示,ZnO纳米粒子成功的生长在CNFs表面上,而没有聚集在一起,生长在CNFs表面上的氧化锌纳米粒子的密度可通过反应溶液的浓度控制.     

纳米碳纤维复合材料的制备及其力学性能研究

采用浓酸(浓硫酸/浓硝酸)氧化法对纳米碳纤维进行表面处理,在水热和超声分散条件下,制备了纳米碳纤维/环氧树脂复合材料。红外光谱测试结果表明,酸化处理在纳米碳纤维表面引入了羟基和羧基等能参与环氧树脂固化反应的官能团。处理后纳米碳纤维的分散性有了明显的改善和提高。SEM和复合材料拉伸性能测试结果也显示了酸化处理能有效改善纤维与树脂的界面结合状况,提高复合材料的拉伸性能。当酸化处理纳米碳纤维的质量分数为0.1%时,复合材料的拉伸强度达到最大值,是纯树脂的1.8倍,是同含量未处理纳米碳纤维材料的1.6倍。