Preparation and Structure Characterization of Mullite Fiber Porous Ceramic

Author(s):  
Hui Wang ◽  
Ling Ke Zeng
2008 ◽  
Vol 368-372 ◽  
pp. 809-811 ◽  
Author(s):  
Hui Wang ◽  
Ling Ke Zeng

Mullite fiber porous ceramic was prepared by forced liquid displacement forming and using Mullite precursor sols as binders. SEM studies have shown that the uniformity of integral ceramic is good although the binder and fiber congregate slightly. Mullite precursor sols spread to films or congregate together in miniature. The mullite sol binders between fibers limit to the contact points and the redundant binders form flat film even if they are superfluous, and the pores were not built up even where the binders congregate badly. The results from mercury porosimetry testing of the mullite fiber porous ceramic showed the relationship of cumulative intrusion and diameter for mullite fiber porous ceramic using colloidal mullite binder, and the mean pore size is 45.6μm. The pore size distribution is very broad, from about 0.2 to 174.9μm.


Author(s):  
X. Zhang ◽  
Y. Pan ◽  
T.T. Meek

Industrial microwave heating technology has emerged as a new ceramic processing technique. The unique advantages of fast sintering, high density, and improved materials properties makes it superior in certain respects to other processing methods. This work presents the structure characterization of a microwave sintered ceramic matrix composite.Commercial α-alumina powder A-16 (Alcoa) is chosen as the matrix material, β-silicon carbide whiskers (Third Millennium Technologies, Inc.) are used as the reinforcing element. The green samples consisted of 90 vol% Al2O3 powder and 10 vol% ultrasonically-dispersed SiC whiskers. The powder mixture is blended together, and then uniaxially pressed into a cylindrical pellet under a pressure of 230 MPa, which yields a 52% green density. The sintering experiments are carried out using an industry microwave system (Gober, Model S6F) which generates microwave radiation at 2.45 GHz with a maximum output power of 6 kW. The composites are sintered at two different temperatures (1550°C and 1650°C) with various isothermal processing time intervals ranging from 10 to 20 min.


2020 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Yu-Hao Deng

High-resolution TEM (HRTEM) is a powerful tool for structure characterization. However, methylammonium lead iodide (MAPbI3) perovskite is highly sensitive to electron beams and easily decomposes into lead iodide (PbI2). Misidentifications, such as PbI2 being incorrectly labeled as perovskite, are widely present in HRTEM characterization and would negatively affect the development of perovskite research field. Here misidentifications in MAPbI3 perovskite are summarized, classified, and corrected based on low-dose imaging and electron diffraction (ED) simulations. Corresponding crystallographic parameters of intrinsic tetragonal MAPbI3 and the confusable hexagonal PbI2 are presented unambiguously. Finally, the method of proper phase identification and some strategies to control the radiation damage in HRTEM are provided. This warning paves the way to avoid future misinterpretations in HRTEM characterization of perovskite and other electron beam-sensitive materials.


2009 ◽  
Vol 38 (5) ◽  
pp. 500-501 ◽  
Author(s):  
Jiang Zhang ◽  
Shaojun Liang ◽  
Guiping He

2013 ◽  
Vol 130 (1) ◽  
pp. 710-710
Author(s):  
Ali Abdulkhani ◽  
Alinaghi Karimi ◽  
Ahmad Mirshokraie ◽  
Yahya Hamzeh ◽  
Nathalie Marlin ◽  
...  

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