关键词： 陶瓷   显微结构   物质组分   性能  

摘要： 陶瓷材料的显微结构与化学组成、制瓷工艺、材料性能间的关系,可用图1所示的正三角形来表征.该图从原子数量级的晶体结构特性(如键性、晶格类型等)来说明组成、工艺、性能与显微结构间的联系,具有典型的结晶化学和晶体物理学的规律性.

关键词： 循环渣   高铝   耐火材料   抗侵蚀性  

摘要： 本文详尽介绍Cr_2O_3对高铝耐火材料的影响及其蚀变蚀损机理。就抗侵蚀性及显微结构,对四种普通高铝耐火制品和两种含铬高铝耐火制品进行鉴定。循环渣试验后对耐火材料进行了各种分析,结果表明:含铬产品的抗渣性优于不含铬产品。有三个论据支持这一结论。其中包括:1.渣/砖界面形成的铬——尖晶石;2.界面下形成的不渗透莫来石层;3.铬—铝固溶体的形成改进了基质结合。

关键词： BiPbSrCaCuO   超导陶瓷   显微结构  

摘要： 本文通过扫描电子显微镜等实验手段,研究了Bi系超导材料在不同制备条件下的显微结构,着重分析了压力下(冷压、热压)样品显微结构的变化。经过压力处理,超导晶粒的平均尺寸显著降低,气孔率大幅度减少,样品密度得以极大提高,达理论密度的90--95％。在经冷压、热压处理的样品中可见到明显的晶粒择优取向排列,其形成机制是压力下的塑性流变以及晶粒的各向异性生长趋势。

关键词： 超导电性   微结构   BiPbSrCaCuO   Si  

摘要： 自从Maeda等人发现Bi-Sr-Ca-Cu-O材料的超导电性以来,Bi系体材料和薄膜材料的研究已取得了重大的进展。为了实际应用的需要,直接在Si或SiO₂衬底上制备Bi-Sr-Ca-Cu-O膜是很必要的,因此需要知道Si对Bi系材料超导电性的影响。本文报道了掺Si对Bi-Pb-Sr-Ca-Cu-O体材料的超导电性的影响的初步研究结果。

关键词： 锆刚玉莫来石   碳化硅   耐火材料  

摘要： 采用OM、SEM、TEM及EDAX等手段研究了锆刚玉莫来石-碳化硅复合材料的显微结构。结果表明,ZrO_2及SiC均匀地分散于刚玉/莫来石构成的基质中。刚玉-刚玉(或莫来石)及莫来石-莫来石的晶间表面多数存在非晶质薄膜,但也有刚玉-莫来石两相直接结合的相界因扩散而形成固溶层。ZrO_2-刚玉(或莫来石)及SiC-刚玉(或莫来石)的相表面因相间扩散形成固溶层或扩散层而皆属直接结合。在刚玉和莫来石晶体里观察到有晶内ZrO_2存在,其形成原因可能是在烧结过程中,刚玉或莫来石晶体再结晶长大而包裹ZrO_2微粒所致。

关键词： TiO2   V2O5   湿敏材料   微结构   湿度灵敏度   多孔陶瓷湿度传感器  

摘要： 本文研究了不同晶型TiO_2材料、烧结温度及烧结时间对TiO_2-V_2O_5系多孔陶瓷湿敏材料的微结构及湿敏性能的影响。实验表明:采用TiCl_4水解法制得TiO_2具有很高的湿度灵敏度。材料在900～1200℃下烧结1～2h,易获得颗粒大小及气孔一定分布的湿敏材料。

关键词： toughness   microstructure   bridging   reinforcement   transformation toughening  

摘要： The fracture toughness of ceramics can be improved by the incorporation of a variety of discontinuous, elastic reinforcing phases that generate a crack-bridging zone. Recent models of toughening by crack-bridging processes are discussed and used to describe the behavior observed in whisker-reinforced ceramics. The toughening response in ceramics reinforced with other types of discontinuous reinforcements is then considered (e.g., matrix and second-phase platelike grains, elongated matrix grains, and grain-size effects in non-cubic matrices). It is shown that crack-bridging toughening processes can be combined with other bridging mechanisms and with other toughening mechanisms (e.g., transformation toughening) to achieve synergistic effects. From these discussions, it is shown that the design of the toughened materials relies heavily on the control of the material properties and microstructural components influencing the toughening behavior to optimize the contributions of both the reinforcing phase and the matrix.

关键词： .EDS  

摘要： Metal Matrix Composites have several advantages over the matrix alloys, such as higher stiffness and strength, but they suffer from lower fracture toughness. This is, of course, dependent on the chemical composition of the matrix and of the reinforcement and also on the microstructure and on the processing techniques. The reactions between the different phases in the materials, in particular the matrix / reinforcement interfaces condition strength and toughness. The purpose of the present paper is to outline the potential of different analytical electron microscopy techniques (direct imaging, EDS, EELS, convergent beam diffraction) for the characterization of magnesium segregation in the case of oxide and non-oxide reinforcements. This allows to identify MgAl2O4 spinel at the interface between alumina and an aluminium base matrix, and to understand the different chemical reactions which are involved in the processing.

关键词： 纳米尺寸   微结构   电子器件   制备  

关键词： Composite Materials  

摘要： An extensive microstructural characterization of Al2TiO5, MgO-stabilized Al2TiO5, and Al2TiO5/mullite/ZrO2 composites, stabilized and unstabilized, was performed using scanning electron and transmission electron microscopy. Complete disorder was found by high-resolution electron microscopy in the cationic sublattice of Al2TiO5, even in the presence of Mg. An analysis of Burgers vectors of dislocations in Al2TiO5 is presented. EDXS analysis of the aluminum titanate bulk in MgO-stabilized samples gave direct evidence for the formation of solid solutions of the type Al2(1-x)MgxTi1+xO5 with improved thermal stability. TEM revealed the presence of a glassy phase in all samples. EDXS analysis of the glassy phase showed repartition of Mg between the Al2TiO5 matrix and the glass, reducing the effectiveness of the stabilizing agent MgO. Intergranular ZrO2 inclusions were found to interact with microcracks, yielding improved mechanical strength of the composite samples.