香螺壳的结构和微观力学性能

测量产自黄/渤海海域的香螺贝壳的硬度和弹性模量,研究了贝壳的结构与性能之间的关系.结果表明,香螺贝壳主要由方解石和文石两种矿物镶嵌在有机质中构成,方解石结构为不均匀的柱状晶,文石结构为多级超微的交错纹状结构,其中第三级结构为10-80 nm的纳米级纤维.文石的力学性能优于方解石的性能.贝壳类复合材料的压痕效应主要源于裂纹扩展,而微观裂纹扩展与晶体类型以及晶体结构的排列方式是密切相关的.方解石裂纹形状曲折、不规则且沿着方解石层的边界扩展,抗裂纹扩展能力较差;而文石压痕周围平直清晰,裂纹沿着其二级结构界面扩展,性能较好.     

烧水壶水垢矿物组成及成因分析

用XRD、IR、SEM研究了家用烧水壶水垢矿物物相组成、相含量以及矿物形貌,并探讨了各物相成因。研究发现,家用热水壶水垢化学成分主要为碳酸钙,矿物物相主要由文石和方解石组成,以文石相为主,质量占92．8％,方解石占7．2％。文石相主要形成于70～90℃,而方解石则主要形成于较低温度。     

香螺壳的结构特征和晶体学取向分析

用光学显微镜和扫描电镜分别观察了香螺壳组织结构和断口形貌,用X射线对各个层面的晶体学取向进行了分析.实验结果表明香螺贝壳由一层柱状方解石和两层交错文片状的文石构成.两层文石层沿横、纵截面方向晶体排列方向相反,其中的文石小板片的排列方向则是互相交替的,且由多级超微结构构成.香螺壳的各个层面的晶体排列存在着明显的择优取向,方解石层择优取向为(104)晶面平行于层面,两层文石层的择优取向为(012)晶面平行于层面,其c轴并不垂直于层面,而是斜交于层面.     

鲍鱼壳的结构和力学性能

以皱纹盘鲍鱼壳为对象,研究了其结构与力学性能之间的关系.研究表明,鲍鱼壳主要由方解石和文石构成,且外层为方解石,内层为文石.鲍鱼壳的力学性能随其加热温度的升高而明显降低,密度也呈现同样的变化,说明鲍鱼壳中所含有的少量有机质随着加热温度的升高而减少,致使鲍鱼的力学性能明显下降.     

退火对高速电铸镍组织和塑性的影响

采用高速电铸方法制备电铸镍,研究退火温度对电铸镍的微观组织和力学性能的影响。分别利用光学显微镜、X射线应力测定仪、显微硬度计来分析电铸镍的微观组织,残余应力和维氏硬度HV的变化,并通过拉伸实验测定电铸镍的伸长率和抗拉强度。结果表明:电铸镍分为内层和外层两个区域,内层由粗大的柱状晶组成,外层由细小的柱状晶组成,退火时电铸镍发生回复和再结晶;未经退火处理的电铸镍伸长率为14%,内层硬度为193,外层为263,抗拉强度σb为625MPa;经不同温度退火后,电铸镍的塑性均有改善,硬度和抗拉强度均有下降。电铸镍在550℃退火2h后,伸长率可达32%,内层硬度为173,外层为165,σb为460MPa。     

仿生矿化的研究I.文石型碳酸钙的合成

在聚乙二醇（ＰＥＯ）存在下，ＣａＣｌ２和Ｎａ２ＣＯ３反应生成了类似红鲍鱼壳的含有ＰＥＯ的碳酸钙－高聚物复合材料。Ｘ－衍射和电镜照片显示，它有两种微观结构：外层为文石型和方解石型结构，内层为针状文石型结构。热重分析表明，该材料中含有３％在右ＰＥＯ。结果说明，聚合物对碳酸钙晶核的形成和晶体的生长有很大影响，并对其形成机理进行了初步探讨。     

AM60B镁合金微弧氧化膜层的结构与性能研究

为了提高镁合金的耐腐蚀性能,用微弧氧化方法在AM60B镁合金表面生成了氧化物膜层.利用扫描电镜、X射线衍射分析了膜层的形貌、结构和组成.研究表明,氧化膜可分为两层,外层疏松多孔,内层结构致密,膜层主要由MgO、Mg2SiO4和少量MgAl2O4相组成,从外层到内层,Mg2SiO4相含量减少,MgO相含量增大.与镁合金基体相比,氧化物膜层表面硬度提高7～8倍. 在质量分数为3.5%NaCl溶液中的动电位极化测试表明,微弧氧化处理使镁合金的耐蚀性能得到了明显提高.     

仿生矿化的研究Ⅰ．文石型碳酸钙的合成

在聚乙二醇（ＰＥＯ）存在下，ＣａＣｌ２和Ｎａ２ＣＯ３反应生成了类似红鲍鱼壳的含有ＰＥＯ的碳酸钙──高聚物复合材料。Ｘ－衍射和电镜照片显示，它有两种微观结构：外层为文石型和方解石型结构，内层为针状文石型结构。热重分析表明，该材料中含有３％左右ＰＥＯ。结果说明，聚合物对碳酸钙晶核的形成和晶体的生长有很大影响，并对其形成机理进行了初步探讨。     

化学能转为绿色新能源技术

本技术是由20多种化学元素组成,在反应釜中设置多层石墨盒,其内部设有红外线电器装置,用来引燃与预热石墨反应堆,使若干种类金属石墨元素,在反应堆中进行有层次的反应.而反应堆的外层壳体与内层壳体之间为真空层,使其隔绝温度保持不受大量损害,起保温作用.……     

Nb-Ti-Si基超高温合金表面Si-Al-Y共渗层的组织形成

研究了包埋共渗温度和渗剂中Al含量对Nb-Ti-Si基超高温合金表面Si-Al-Y共渗层显微组织的影响.采用组成为10Si-10Al-3Y-5NaF-72Al2O3(wt%)的渗剂,分别在1050、1080和1150℃保温10h所制备的渗层具有相似的结构,由(Nb,X)Si2(X代表Ti,Cr和Hf)外层、(Nb,X)5Si3中间层、(Cr,Al)2(Nb,X)和(Nb,X)Al3相构成的次内层及(Nb,X)2Al内层组成.在1050℃/10h所制备渗层的外层和中间层的组成相随渗剂中Al含量增加而变化,但次内层和内层的组成相不改变.当渗剂中Al含量为15wt%时,渗层外层仍为(Nb,X)Si2,但中间层却由(Nb,X)Al3和(Nb,X)5Si3两相组成;当渗剂中Al含量为20wt%时,渗层外层转变为由(Nb,X)Si2和(Nb,X)3Si5Al2两相组成.对1050℃/10h所制备的渗层(采用Al含量为15wt%的渗剂)进行1250℃/0.5h氧化,氧化膜厚度约为10μm,主要由Al2O3、TiO2和SiO2组成.     

Scanning electron microscopic structure of the prismatic layer in the Bivalvia

The shell structure of the Bivalvia has been observed with the use of optical and electron microscopes since the early 1900’s. The prismatic structure is one of the more attractive shell structures in bivalved mollusks. This structure is composed of the aggregation of polygonal prisms arranged densely. Each prism is made of small calcite crystallites arranged perpendicular to a growth shell surface. Organic materials, named organic sheaths, accumulate around prisms and stain well with heamatoxylin-eosin.The Bivalvia, which make prismatic structures, are divided into two groups. One group has the inner shell layer made up of a nacreous structure, and the other has the inner shell layer made up of a foliated structure. The aragonite prismatic layer and the prismatic layer are closely related to each other, as is the aragonite prismatic layer to the composite prismatic one.     

Scanning electron microscopic structure of the prismatic layer in the Bivalvia

The shell structure of the Bivalvia has been observed with the use of optical and electron microscopes since the early 1900’s. The prismatic structure is one of the more attractive shell structures in bivalved mollusks. This structure is composed of the aggregation of polygonal prisms arranged densely. Each prism is made of small calcite crystallites arranged perpendicular to a growth shell surface. Organic materials, named organic sheaths, accumulate around prisms and stain well with heamatoxylin-eosin. The Bivalvia, which make prismatic structures, are divided into two groups. One group has the inner shell layer made up of a nacreous structure, and the other has the inner shell layer made up of a foliated structure. The aragonite prismatic layer and the prismatic layer are closely related to each other, as is the aragonite prismatic layer to the composite prismatic one.     

Microstructural Characterization and Hardness Behavior of a Biological Saxidomus purpuratus Shell

The microstructures of the Saxidomus purpuratus shell were observed.It was found that the inner and middle layers of the shell are composed of crossed lamellae,while the outer layer exhibits porous structures.With the characteristic structure of each layer,the hardness of inner layer with narrow domains in crossed lamellar structure is the highest,and that of middle layer with wide domains is lower,while the outer layer has the lowest hardness.The damage morphologies of the indentations change a lot,depending not only upon the magnitude of the indentation load,but also upon the orientation between the indentation direction and the crossed lamellae in the microstructure of the shell,which illustrates the anisotropy in mechanical properties of such shells.     

Aragonite observed in the prismatic layer of seawater-cultured pearls

The prismatic layer is obviously different from the parallel layer in seawater-cultured pearls. X-ray diffraction (XRD), optical microscopy (OM) and micro-infrared (IR) spectroscopy have been applied to characterize the crystallized layers of high- and low-quality seawater-cultured pearls produced in South China. The result shows that the prismatic layer is not only composed of calcite as reported in previous researches. Three types of prisms were found in seawater-cultured pearls: calcite prism, aragonite prism and calcite and aragonite prism. Therefore, we have a new understanding of the biomineralization of the prismatic layer in seawater-cultured pearls. The result makes us review the traditional viewpoint that the increased content of aragonite improves the quality of pearls. We discovered that some seawater prismatic pearls almost completely composed of aragonite have the worst quality. We thought that the thickness and the spatial distribution of prisms are the main factors that can affect the quality of seawater-cultured pearls.     

Structural characterization and mechanical behavior of a bivalve shell (Saxidomus purpuratus)

The structure and mechanical behavior of Saxidomus purpuratus bivalve shell were investigated. XRD results show that the only form of calcium carbonate present in the shell is aragonite. The inner and middle layers have a cross-lamellar structure, while the outer layer has porosity and does not have tiles, but instead has ‘blocky’ regions. The hardness of middle and inner layer are close in both plane view and cross section, but the hardness of outer layer is significantly less, especially in the plane view. The compressive strengths with loading along the three orientations were established and significant differences were found. The Weibull strength at 50% of the probability of failure varies between 59 and 148 MPa and is dependent on the loading orientation and in condition of shell (dry vs. hydrated). These differences are interpreted in terms of the anisotropic structure and coarser structure of the external layer.     

Structural whiteness of the multi-component glaze dependence on amorphous photonic crystals

A kind of enhancing mechanism of structural whiteness dependence on amorphous photonic crystal (APC) structure is introduced in this paper. In the glaze system composed of albite, kaolin, talc, calcite, quartz, titanium dioxide and zinc oxide, the APC structure will be produced by using quartz as a variable to induce the phase separation. Under different polarities between Ti, Zn etc. and Siion, the separated spheres with the core-shell structure can be obtained and then make up opal-like APCs in the glaze layer. In addition to inner and outer layers of core-shell spheres, the calculated results of refractive indices clearly show the great difference between the particles and the matrix. As a result of different refractive indices, the multiple scatting of visible light plays a key rote in the structural whiteness. However, due to the decrease of the cationic content, APCs with the reverse opal structure would be formed in the interface between glaze and body. Ultimately, the glaze appearance reveals extremely high structural whiteness due to the special APC structure.     

三角帆蚌贝壳的微结构及尺寸变化特征

天然生物经历了亿万年的不断进化,已经形成了近乎完美的结构。天然生物材料结构的研究是仿生研究的基础,本文以三角帆蚌贝壳为研究对象,利用SEM和AFM,描述了三角帆蚌贝壳的微结构特征,包括其角质层、棱柱层、珍珠层及界面和晶带的形貌,揭示文石晶片及各层间的尺寸变化规律。研究表明:角质层内部分布大量裂纹,珍珠层与棱柱层无明显过渡界面,珍珠层内发现条状晶带结构缺陷;贝壳壳体和珍珠层厚度随0生长线向外呈现先增大后减小的变化趋势,且单层文石晶片的厚度不均,最厚处可达最薄处的2倍多。对三角帆蚌贝壳的结构进行了深入研究,为其优异的力学性能提供了理论依据,为未来的仿生结构设计提供了新思路和新想法。