多晶硅冶金法除磷的研究进展

磷是多晶硅中的一种主要杂质元素,目前国内外采用冶金法除磷的工艺主要包括酸洗除磷、合金定向凝固除磷和真空除磷工艺。其中,酸洗除磷工艺可以很有效地去除磷杂质,但仍未达到太阳能级多晶硅小于0.1×10-4%(质量分数)的要求。采用合金定向凝固工艺可以去除80%以上的磷杂质,但目前对凝固后硅中残留溶剂金属的去除方法还有待进一步的研究。通过真空感应熔炼实验已将磷含量从15×10-4%(质量分数)降低至0.8×10-5%(质量分数),并对除磷的热力学条件进行了初步探索

Preparation and toughening characterization of high fracture toughness Si3N4 ceramic with rodlike structure

Silicon nitride ceramic has many advantages in high temperature structural applications such as high strength, creep resistance, and chemical stability. A disadvantage, however, has been its low fracture toughness, typically 4 to 6 MPa m1=2[1]. Whiskerreinforcement is an alternative approach to increase the fracture toughness of Si3N4ceramic, but there exist many problems to be solved such as whisker dispersion, densification, and whisker stability. Re-cently, a new technique called ‘‘self-reinforcement’’ or ‘‘in situtoughening’’ has been applied to improve the fracture toughness of this ceramic, with toughness values reported as high as 8 to 14 MPa m1=2usinggas-pressure-sintering (GPS) or hot-pressing (HP) method in different additive systems

Preliminary Study on Thermochemical Curing of Polycarbosilane Fibers

［中文文摘］以异丙醇锆(ZIP)为交联剂、聚碳硅烷(PCS)为先驱体,在Ar气氛的保护下通过干法纺丝、热化学交联工艺使PCS从热塑性转变热固性结构。研究了该工艺对PCS纤维质量变化、Si-H反应程度、溶解性及氧含量等性能的影响。实验结果表明:在不熔化过程中,PCS结构中的Si-H键与ZIP反应,在PCS分子间形成Si-O-Zr交联结构,随着交联温度和保温时间的升高,Si-H反应程度和纤维失重率相应提高;在测试范围内最大Si-H反应程度为73.06%,失重率2.678%,氧含量低于2.0%。［英文文摘］Polycarbosilane from dry spinning to SiC fiber through thermochemical curing,which is catalysed by zirconium iso-propoxide(ZIP) under Ar gas stream,is transformed from thermoplastic to thermoset structure.The effects of curing temperature and holding time on cured PCS fibers are mainly studied in this paper.The experimental result shows that Si-H bonds in polycarbosilane are crosslinked by ZIP during the curing process which is made up of Si-O-Zr structure in PCS molecule.And the reaction degree of Si-H bonds and mass loss of fibers are increased accordingly with thetemperature and holding time rising.The maxium reaction degree of Si -H bonds is 73.06%, mass loss 2.678%,and oxygen content no more than 2.0%, respectively.总装备部预研基金资助(51412020404QT870

苯并咪唑类光电功能配合物的研究进展

主要概述了苯并咪唑类光电材料的研究进展。苯并咪唑类配合物的电致发光材料成膜性好、热稳定性高和色纯度高,但发光效率、寿命等仍偏低,发光机理尚不清楚;苯并咪唑类配合物具有良好的刚性平面结构和丰富的π电子,选择合适的离子掺杂,有可能得到高效的发光材料;苯并咪唑类配合物还可用于制备有机太阳能电池,其钌配合物的染料敏化太阳能电池保持着最高的光电转化效率

骨灰煅烧改性对骨质瓷性能的影响

骨灰是烧制骨质瓷的最重要的原料,提高骨灰的质量也是提高骨质瓷性能的关键.对骨胶厂提供的骨灰进行煅烧处理,通过红外、热分析、X射线衍射和扫描电镜等表征手段系统地研究了煅烧温度对骨灰的显微形貌和结构变化的影响规律,以及骨灰煅烧改性对坯体浆料流动性和坯体烧结工艺的影响规律.实验结果表明,在1 200℃下对骨灰进行煅烧,可获得轮廓清晰、圆球形和颗粒尺寸适中的煅烧骨灰,有利于提高骨质瓷坯体浆料的流动性,扩大坯体烧结温度范围,并且能提高坯体的白度.通过合理配方和工艺优化,骨质瓷坯体烧结后白度为92.97%,密度为2.70 g/cm3,收缩率为16.83%

Redistribution of iron during directional solidification of metallurgical-grade silicon at low growth rate

研究冶金级硅低速定向凝固过程中杂质铁的再分布。采用ICP-MS检测铁的浓度,绘制铁在固相、液相、晶界和晶体生长方向上的浓度示意图。铁浓度在固、液相中具有明显差异。依据质量守恒定理,计算得出溶质边界层约为4 mm,铁的有效分凝系数约为2.98×10~(-4)。在低速凝固条件下,铁容易偏析聚集在晶界。在生长方向上,由于低速凝固,铁浓度在硅锭86%高度以下几乎恒定,不完全符合Scheil方程规律。讨论了对流对铁再分布的影响,对流"死区"对铁再分布具有重要影响。Redistribution of iron during directional solidification of metallurgical-grade silicon(MG-Si) was conducted at low growth rate. Concentrations of iron were examined by ICP-MS and figured in solid and liquid phases, at grain boundary and in growth direction. Concentrations are significantly different between solid and liquid phases. The thickness of the solute boundary layer is about 4 mm verified by mass balance law, and the effective distribution coefficient is 2.98×10~(-4). Iron element easily segregates at grain boundary at low growth rate. In growth direction, concentrations are almost constant until 86% ingot height, and they do not meet the Scheil equation completely, which is caused by the low growth rate. The effect of convection on the redistribution of iron was discussed in detail. Especially, the "dead zone" of convection plays an important role in the iron redistribution.Projects(51334004,51204143)supported by the National Natural Science Foundation of China;; Project(2006L2003)supported by the Scientific Technological Innovation Platform of Fujian Province,Chin

Research Development of Curing Treatment of Polycarbosilane to Prepare Continuous SiC Fibre

［中文文摘］综述了先驱体转化法制备SiC纤维过程中聚碳硅烷(PCS)的各种不熔化处理方式及其发展状况。通过不熔化方式对终烧产物SiC纤维性能的比较,讨论了各种不熔化方式的优缺点及其对SiC纤维中氧含量的影响,并指出了制备高性能SiC纤维不熔化技术研究的国内外差距及发展趋势。［英文文摘］Different curing treatment methods of polycarbosilane fibres in the process of fabricating SiC ceramic fibres by preceramic polymer pyrolysis usually containing polymer synthesis, spinning, curing and pyrolysis, are reviewed in this paper. Current development situation of these manners is thoroughly presented. By comparing the element composition and mechanical properties of SiC fibre from different cross-linking manners, some advantages and drawbacks of these methods, and their effects on the oxygen content in SiCfibre are also discussed. Moreover , the developmental trend of cross　linking technique to fabricate excellent heat2resistant SiC fibres is proposed

R&D of composite thin films

［中文文摘］复合薄膜材料由于具有传统复合材料和薄膜材料两者的优点,正成为复合材料的重要分支而越来越引起广泛的重视和深入的研究。它可以把各层薄膜材料的优异性能结合起来,从而克服各自的弱点,达到特定的应用目的。本文简要综述了近十年来复合薄膜领域的研究进展,介绍了多层复合薄膜的制备方法和常用表征手段并总结了目前复合薄膜材料领域中存在的主要问题。［英文文摘］Having the advantages of both conventional composite materials and thin films,the composite thin films have been more and more attractive in materials technology and widely used in mamy fields.The reason why composite thin films are so attractive is just that they can combine the advantages of each amd every layer of a film together and get rid of the disadvantage of each one,thus serving the special purpose of application.Reviews briefly the R&D of composite thin films in recent ten years and describes the preparation of composite multilayer thin films and commonly used characterixation procedures,and indicaters mainly the existing problems of such thin films.国家863计划国防先进材料重大专项基金资助项目(2003AA305040

分光光度法测定多晶硅中铁和铝

将多晶硅(硅粉)用氢氟酸和硝酸二次溶解,用高氯酸的二次冒烟去除氟离子对铝的干扰,用3 cm的比色皿解决铁低灵敏度带来的误差大的问题。使用分光光度法准确测定多晶硅中铁和铝的含量。研究了显色条件对显色反应的影响,确定最佳实验条件。结果表明,在pH3~5的乙酸-乙酸钠缓冲溶液中,铁与5 mL 0.25 g/L的1,10-二氮杂菲10 min后生成稳定的红色络合物,且在2~10μg/50 mL范围内服从比尔定律;在pH 5.5~6.1的六次亚甲基四胺缓冲溶液中,铝与5 mL 0.3 g/L的铬天青-S在15 min后形成稳定的紫红色络合物,且在4~16μg/50 mL范围内服从比尔定律。用分光光度法能准确测定纯度为99.99%多晶硅(硅粉)中铁和铝含量,并与ICP-AES法测试结果对比,相对误差在5%左右

FIBER-REINFORCED COPPER MATRIX COMPOSITES FABRICATED BY ELECTROCHEMICAL INFILTRATION TECHNIQUE

［中文文摘］基于电化学浸渗技术(ECI)在室温下制备了连续铜纤维、碳纤维和玻璃纤维增强铜基复合材料。实验结果表明,在本实验工艺条件下可获得致密的纤维/Cu基复合材料,并具有优良的力学性能。复合材料的断口形貌及显微结构的SEM观察表明,纤维与铜基体之间的界面结合良好,纤维不受任何损伤。证实了ECI在室温下快速制备纤维增强金属基复合材料的可行性。［英文文摘］Continuous-fiber-reinforced Cu matrix composites were fabricated based on the electrochemical infiltration technique (ECI). The experimental results show that the dense fiber/Cu composites have been obtained on the present condition, which possess good mechanical properties. The fracture surface morphology and microstructures of the composites have been observed by SEM. It is indicated that the interfacial bond between fibers and Cu matrix is very well and the fibers do not have any damage. The ECI is　feasible to prepare rapidly fiber reinforced metal matrix composites at room temperature