晶须表面涂层对SiCw／TZP陶瓷复合材料力学性能和界面结构的影响

研究了在ＳｉＣ晶须表面涂覆１０～１００ｎｍ厚的氧化铝或莫来石对１５％（ｖｏｌ）ＳｉＣｗ／２．５Ｙ－ＴＺＰ陶瓷复合材料力学性能的影响。结果表明：涂层可显改善复合材料的力学性能，其中涂覆莫来石效果最佳，室温σ１＝１４５０ＭＰａ，Ｋ１ｃ＝１７ＭＰａ·ｍ＾１／２，１０００℃下σｆ＝５２０ＭＰａ，比无涂层的复合材料力学性能分别提高了８０％，１００％和４５％。ＳＥＭ，ＴＥＭ和ＨＲＥＭ观察表明：ＳｉＣｗ表面涂     

纳米SiC—Si3N4复合粉体制备材料的显微结构

以自制的纳米ＳｉＣ－Ｓｉ３Ｎ４复合粉体为原料，用气压烧结的方法制备陶瓷复合材料。对此材料用ＴＥＭ和ＨＲＥＭ电镜显微分析的结果发现两种不同的显微结构：纳米－微米结构和亚微米－微米结构。对两种结构的形成机理作了初步的探讨。     

纳米SiC－Si_3N_4复合粉体制备材料的显微结构

以自制的纳米ＳｉＣ－Ｓｉ＿３Ｎ＿４复合粉体为原料，用气压烧结的方法制备陶瓷复合材料。对此材料用ＴＥＭ和ＨＲＥＭ电镜显微分析的结果发现两种不同的显微结构：纳米－微米结构和亚微米－微米结构。对两种结构的形成机理作了初步的探讨。     

AlN／SiCw（Y2O3＋SiO2）复合材料热处理增强研究

研究了热处理对ＡｌＮ／ＳｉＣｗ（Ｙ２Ｏ３＋ＳｉＯ２）复合材料机械性能的影响。结果表明，该材料经热处理后的强度提高，当添加剂Ｙ２Ｏ３／ＳｉＯ２＝１／２．５摩尔比时，提高幅度最大。经ＸＲＤ，ＳＥＭ，ＴＥＭ／ＥＤＡＸ和ＨＲＥＭ分析，热处理增强的机理主要是粒界玻璃相在高温氧化气氛中和ＡｌＮ颗粒表层作用，生成的纤维２Ｈ＾δＳｉａｌｏｎ相和ＳｉＣｗ形成空间交错结构。     

Ti－Zr－N三元陶瓷调幅相的结构与成分分析

通过对高纯ＴｉＺｒ（Ｔｉ／Ｚｒ＝５０／５０，原子百分比）合金的高温氮化和高温退火制取了Ｔｉ－Ｚｒ－Ｎ三元系复合陶瓷实体材料。应用ｘ射线衍射（ＸＲＤ）、扫描及透射电子显微镜（ＳＥＭ，ＴＥＭ）、电子能量损失谱（ＥＥＬＳ）等方法分析研究了该（Ｔｉ，Ｚｒ）Ｎ复合陶瓷材料中调幅相的晶体学性质、显微结构特征及化学组成。     

SiCw/3Y-TZP/ZrSiO4复相陶瓷的力学性能

在考查ＳｉＣｗ－ＴＺＰ各自对锆英石陶瓷的强化增韧领航物基础上,研究了二者对锆英陶瓷的协同补强增韧行为。结果发现：在补强剂引入量相同的情况下,ＳｉＣ晶须和３Ｙ－ＴＺＰ同时引入产生的增韧效果明显高于二者单独引入锆英石基体所产生的增韧效果之和,表明在锆英石英基体中ＳｉＣ晶须和３Ｙ－ＴＺＰ的增韧行为具有协同效果。在采用ＸＲＤ,ＴＥＭ和ＳＥＭ等手段对复相材料的相组成和显微结构进行研究和观察的基础上提出：二者     

Ti—Zr—N三元陶瓷调幅相的结构与成分分析

通过对高纯ＴｉＺｒ（Ｔｉ／Ｚｒ＝５０／５０，原子百分比）合金的高温氮化和高温退火制取了Ｔｉ－Ｚｒ－Ｎ三元系复合陶瓷实体材料。应用Ｘ射线衍射（ＸＲＤ）、扫描及透电子显微镜（ＳＥＭ，ＴＥＭ）、电子能量损失谱（ＥＥＬＳ）等方面分析研究了该（Ｔｉ，Ｚｒ）Ｎ复合陶瓷材料中调幅相的晶体学性质、显微结构特片及化学组成。     

碳化硅晶须增强氮化铝复合材料的机械性能和界面研究

本研究应用热压工艺制备了致密ＳｉＣｗ／ＡｌＮ复合材料，其晶须的质量含量为１０％～３０％。当复合材料中晶须的质量含量达到３０％时，其弯曲强度增加了８５％，韧性提高了５０％。用ＳＥＭ和ＴＥＭ观察了材料的显微结构，指出弯曲强度增加是由于荷载从基体转移到晶须。断裂韧性的增加是由于裂纹偏转、裂纹分支和钉扎等作用引起。用ＨＲＥＭ对ＡｌＮ基体与ＳｉＣ晶须界面进行了初步分析和研究。     

用场解吸质谱法(FDMS)对澄清油中间相沥青组成结构的研究

用场解吸质谱（ＦＤＭＳ）对乙烯渣油中间相沥青（ＥＴＭＰ）和澄清油中间相沥青（ＤＯＭＰ）之甲苯可溶组分（ＴＳ）的组成结构进行了对比研究。通过对两种中间相沥青ＴＳ组分质谱峰的合理归属,鉴定出了主要的组成化合物系列以及各自相对应化合物的结构,分析极限大大扩大,在ＤＯＭＰ－ＴＳ中检测到的最高质量数为９９０,相应于１６个芳环的稠环芳烃分子;在ＥＴＭＰ－ＴＳ中检测到的最高质量数为９４８。相应于１５个缩合芳环的稠环芳烃分子,ＤＯＭＰ－ＴＳ含较多的迫位缩合芳环而ＥＴＭＰ－ＴＳ含较多的渺位缩合芳环,同时对中间相沥青的组成结构与其物理化学性能作了关联。     

AS/MBS/SBR的力学性能及其微观形态

用核壳型粒子ＭＢＳ与ＳＢＲ相配合形成复合改性剂以求对ＡＳ树脂达到良好的协同增韧效果,同时保持其原有优良性能。用ＳＥＭ、ＴＭＡ等方法研究共混体系的微观形态,发现复合改性剂能改善ＡＳ树脂脆性大,动态力学性能差的缺点。     

Investigation on polypropylene and polyamide-6 alloys/montmorillonite nanocomposites

Propropylene (PP) and polyamide-6 (PA6) alloys nanocomposites were prepared using melt intercalation technique by blending PP and PA6 while used organophilic montmorillonite (OMT). The melt intercalation of PP and PA6 alloys was carried out in the presence of a compatibilizer such as maleic anhydride-g-polypropylene (MAPP). Their structures were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and High Resolution Electronic Microscope (HREM). It was found different blend sequences have influence on the dispersibility of OMT and self-assembled structures of OMT appeared in PP and PA6 alloys. The crystallization behavior and crystal structure of PP and PA6 alloys/montmorillonite nanocomposites were investigated by X-ray diffraction. It showed that the blend sequences have influence on crystal structure and a higher cooling rate results in increasing of γ-crystalline phase. Flammability properties are characterized by Cone Calorimeter, which show an unusual phenomenon.     

Influence of molybdenum addition on the microstructure and mechanical properties of TiC-based cermets with nano-TiN modification

Effect of Mo addition on the microstructure and mechanical properties of TiC–TiN(nm)–WC–Co–Ni–C system cermets was studied in the work. Specimens were fabricated by conventional powder metallurgy techniques. The microstructure was investigated using transmission electron microscope (TEM) and the scanning electron microscope (SEM). Chemical compositions of different phases such as ceramic phase with core/rim structure [the core being TiC and rim being (Ti,W,Mo)(C,N)] and metallic phase were analyzed quantitatively by EDX. Mechanical properties such as flexural strength, fracture toughness and hardness were also measured. Results show that flexural strength and fracture toughness have a trend to decline with increasing Mo addition, but the change of hardness is not apparent with the increase of Mo addition. Results also reveal that finer microstructure and thicker rim phase will be obtained with the increase of Mo addition. The optimal addition of Mo can be estimated to be 4 wt.% with respect to TiC–10TiN(nm)–15WC–5Co–Mo–5Ni–1C system cermets. Fracture micrographs show that main failure mode of the cermets is a mixed one, i.e., trans-granular and inter-granular fractures both exist.     

有机锡参与合成P(BA-EHA)/PVC及共混改性PVC的结构与性能

通过种子乳液聚合方法,采用丙烯酸丁酯(BA)、丙烯酸2-乙基己酯(EHA)为核层单体,与少量有机锡单体共聚制备了含有机锡的P(BA-EHA)胶乳,与氯乙烯(VC)乳液接枝共聚合成了P(BA-EHA)/PVC复合改性剂。通过透射电子显微镜(TEM)、动态力学分析仪(DMA)、扫描电子显微镜(SEM)等测试手段,考察了复合乳胶粒子和共混材料的形态结构、复合改性剂中有机锡含量对其共混改性PVC材料的力学性能及复合粒子热稳定性的影响。DMA和TEM分析结果表明:复合粒子的加入显著改善了橡胶相与PVC之间的相容性,P(BA-EHA)在PVC基体中具有很好的分散性和均匀度,SEM照片显示共混材料缺口断面表现为优异的基体屈服型断裂韧性。     

多元氧化物纳米丝阵列的电泳沉积

以多孔氧化铝(porous alumina)为模板,用电泳沉积技术组装了高度有序的钛酸钡(BaTiO3)、钛酸锶(SrTiO3)、锆钛酸铅(lead zirconate titanate,PZT)等多元氧化物纳米丝阵列.用扫描电镜(scanning electron microscope,SEM)、透射电镜(transmission electron microscope,TEM)、选区电子衍射(selected area electron diffraction,SAED)、X射线衍射(x-ray diffraction,XRD)等手段表征多元氧化物纳米丝阵列.SEM照片显示:所得纳米丝连续、致密,纳米丝直径略小于模板孔径且模板填充率很高.XRD和SAED显示:纳米丝为多晶钙钛矿型结构.因此,电泳沉积法是一种很有发展前途的制备氧化物纳米丝阵列的方法.     

自组装中孔BCN化合物的合成与表征

以三聚氰胺和硼氢化钠为原料合成具有中孔结构的新颖硼碳氮(BCN)化合物,采用热质量-差示扫描量热(TG-DSC)、X线衍射(XRD)、氮吸附比表面积(BET)、傅立叶红外光谱(FT-IR)、扫描电镜(SEM)、透射电镜(TEM)和荧光光谱(PL)等分析手段对BCN化合物进行表征,研究BCN化合物光致发光性能。结果表明:热分解温度在600℃以上可制备出具有层状石墨结构的BCN化合物。随热分解温度升高至800℃,B、N含量增大,C含量减小,得到化学计量比为2∶1∶2的B2 CN2化合物。荧光光谱(PL)测试证明BCN化合物具有光致发光性。     

Fabrication of fine microcapsulated red phosphorus particles by SCF-RESS with a new structure nozzle

A novel process of preparing microencapsulated red phosphorus particles by rapid expansion of supercritical fluids (RESS) was tested, in which a new kind of nozzle and supercritical CO₂ as a solvent were used. The structure of the microencapsulated red phosphorus particles were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). These results show that red phosphorus particles can be effectively encapsulated with paraffin by using the method. At the same time, how the moisture absorption ratio of microencapsulated red phosphorus particles was dependent on the experimental conditions was further investigated. The results suggest that paraffin-microencapsulated red phosphorus particles show a lower moisture absorption ratio within the experimental conditions of the extraction column and nozzle temperature of 120°C, extraction column pressure of more than 16 MPa, and a mass flow of core particles (0.5 g/min).     

聚丙烯腈预氧化纤维组织结构的遗传与演变研究

采用扫描电镜(SEM)和透射电镜(TEM)仪器和方法,对聚丙烯腈(PAN)原丝和不同温度阶段预氧丝的表面形貌、断面形貌和内部组织结构进行了系统的分析。结果表明,PAN原丝的原纤结构在整个预氧化过程中是具有遗传性的,随着预氧化的不断进行,原纤的韧性逐渐降低,原纤之间的结合更为紧密;预氧化反应由纤维外部向芯部逐步进行,形成了组织致密、脆性高的皮层和组织疏松、韧性高的芯部。皮层区域的晶粒尺寸细小,分布均匀,无择优取向,非晶组织较为致密;而芯部区域的组织粗大,呈现出沿纤维轴向排列的层片状结构,越靠近芯部,层片的取向越明显。     

Structure image of single crystal of polyethylene

High-resolution electron macroscopic images of lamellar single crystal of polyethylene (PE) have been successfully obtained using high-resolution electron microscopy (HREM), although so far the feasibility of obtaining HREM images from such a radiation sensitive polymer is still drastically questioned. The HREM images with a clear two-dimensional periodic structure reported here were recorded in a transmission electron microscope operated at 200 kV. The images consisted of lattice fringes derived from the 〈001〉 zone, and the structure images of different lattice fringes were resolved. To our knowledge, this is the first time that such clear structure images of PE have been reported at a molecular level.     

A novel castor oil-based polyurethane/layered zirconium phosphonate nanocomposites: preparation,characterization, and properties

A new type of layered zirconium glycine-N,N-dimethylphosphonate (ZGDMP), with the functional groups –COOH, has been prepared and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). Situ polymerization method was employed to prepare castor oil-based polyurethane/layered zirconium phosphonate (PU/ZGDMP-n) nanocomposite films. The structure and morphology of ZGDMP in PU matrix have been characterized by XRD, SEM, TEM, and Fourier transform infrared spectroscopy. The results show that the morphology and properties of PU-based nanocomposites greatly depend on the functional groups –COOH because of the chemical reactions and physical interactions involved. The tensile test shows that the tensile strength and elongation at break for the nanocomposite films increase with the loading of ZGDMP as compared to those of the virgin PU.     

Formation of self-organized Zircaloy-4 oxide nanotubes in organic viscous electrolyte via anodization

This work reports the formation of self-organized Zircaloy-4 (Zr-4) oxide nanotubes in viscous organic ethylene glycol (EG) electrolyte containing a small amount of fluoride salt and deionized (DI) water via an electrochemical anodization. The structure, morphology, and composition of the Zr-4 oxide nanotubes were studied using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), EDX, and XPS. SEM results showed that the length of the nanotubes is approximately 13 μm, and TEM results showed that the inner diameter of the Zr-4 oxide nanotubes is approximately 20 nm with average wall thickness of approximately 7 nm. XRD and selected area electron diffraction pattern (SAED) results confirmed that the as-anodized Zr-4 oxide nanotubes have cubic crystalline structure. Both cubic and monoclinic phases were found after annealing of Zr-4 oxide nanotubes. The tubular structure morphology of Zr-4 oxide nanotubes did not remain intact after annealing which is attributed to the elimination of F species from the annealed nanotubes.