Ceramic powder processing characterization

To characterize a ceramic powder, a representative sample must be taken. Methods of sampling and their errors therefore are discussed. Powder characteristics, including shape, size, size distribution, pore size distribution, density, and specific surface area, are discussed. Emphasis is placed on particle size distribution, using log-normal distributions, because of its importance in ceramic powder processing. A quantitative method for the comparison of two particle size distributions is presented, in addition to equations describing the blending of several powders to reach a particular size distribution. 

In this section, we cover only in situ techniques for the analysis of aqueous powder dispersions, because these systems are most relevant to ceramic powder processing. The focus is on electrokinetic methods for the measurement of particle electrostatic potential. In addition, a brief overview of available surface chemical characterization techniques is given. Additional details on this topic are given by other authors in this book. 

The term thermal analysis actually covers many different techniques that measure a change in a material as a function of temperature. Thermal analysis is particularly useful in characterizing decomposition and crystallization during ceramic powder processing. It is then possible to... 

Silicon-containing preceramic polymers are useful precursors for the preparation of ceramic powders and fibers and for ceramic binder applications (i). Ceramic fibers are increasingly important for the reinforcement of ceramic, plastic, and metal matrix composites (2, 3). This chapter will emphasize those polymer systems that have been used to prepare ceramic fibers. An overview of polymer and fiber processing, as well as polymer and fiber characterization, will be described to illustrate the current status of this field. Finally, some key issues will be presented that must be addressed if this area is to continue to advance. 

Thus this book presents current developments and concepts in the chemical techniques for production and characterization of state-of-the-art ceramic materials in a truly interdisciplinary fashion. The 27 chapters are divided into five parts reflecting topical groups. The first part discusses the starting materials—how to prepare and modify them in the nanoscale range. Powders are the most heavily used form of starting ceramic materials. The synthesis, characterization, and behavior of ceramic powders are presented in parts I and II. In the third part, processing of ceramic films via the sol-gel technique is discussed. Fabrication of... 

Bergstrom, L., Surface characterization of ceramic powders, in Surface and Colloid Chemistry in Advanced Ceramics Processing, R.J. Pugh and L. Bergstrom, Eds., Surface Science Series, 51, Marcel Dekker, New York, 1994. 

A series of perovskite compositions were synthesized using oxides and carbonates of the cations by conventional ceramic process. The synthesized powders were characterized using powder x-ray diffraction technique to ensure phase purity. Conductivity measurements were made in H2-H2O atmosphere to determine proton conductity. As the perovskite compositions are inherently mixed conducting, the transference numbers for proton and electron conduction were also determined by varying the partial pressures of hydrogen and steam across the membrane. 

The topic of this chapter is how to produce particles of a particular shape, chemistry, and size and then how to characterize them. We are going to describe the methods used to produce ceramic powders, from the traditional ball-milling technique to more recent vapor-phase approaches that can produce nanometer-sized particles. It is worth remembering that powder processing is used to produce some special metals (e.g., tungsten filaments for incandescent lamps), it is used in the pharmaceutical industry, for making catalysts, and it is used to prepare many food ingredients. 

The density of the compact as a function of the applied pressure is usually used to characterize the compaction behavior of a ceramic powder, which can be used for process optimization and quality control of the green bodies. If the density is plotted... 

The purpose of this effort is to (1) identify and characterize those aspects of the chemistry and physics of the ceramic powder and powder/solvent interface that control processing, (2) develop standard methods of analysis for item (1), and (3) develop procedures for writing specifications for ceramic powders to include any methods of analysis developed in this project. 

R. N. Katz, Characterization of Ceramic Powders pp. 35-49 in Treatise on Materials Science and Technology, Vol. 9, Ceramic Fabrication Processes. Edited by F. F. Y. Wang. Academic Press, New York, 1976. 

Although the characterization of the powder surface area and its role in processing have received considerable attention for decades, it is only within recent years that the importance of surface chemistry in ceramic processing has begun to be recognized. As we have outlined in Chapter 1, the consolidation of fine ceramic powders from liquid suspensions to produce more uniform green bodies has been shown to produce significant benefits in fabrication. In this case, the quality of the microstructure of the consolidated body is controlled by the dispersion behavior of the powder and the interaction between the particles in the liquid, which, in turn, are controlled by the surface chemistry. 

In this chapter we have examined a variety of techniques with broad application to the characterization of ceramic powders. In addition to ceramic processing, powders are also important in several other technologies (e.g., powder metallurgy, catalysis, and pollution control) so that the techniques described here have broader... 

Qiu S, Gao C, Zheng X, Chen J, Yang C, Gan X, Fan H (2008) Pb(Zr(,jTi j)03 powders prepared by aqueous Pechini method using one-step pyrolysis process characterization and porous ceramics. J Mater Sci 43(9) 3094-3100 Ramgir NS, Mulla IS, Vijayamohanan KP (2005) A room temperature nitric oxide sensor actualized from Ru-doped SnOj nanowires. Sens Actuators B 107 708-715... 

Ceramic powders of BaCeo.9Yo.1O2.95 (BCYIO) have been prepared by the sol-gel method [115]. Barium and yttriimi acetate and cerium nitrate were used as ceramic precursors in a water solution. The reaction process studied by DTA-TG and XRD showed that calcination of the precursor powder at r>1000°C produces a single perovskite phase. The densification behavior of green compacts studied by constant heating rate dilatometry revealed that the shrinkage rate was maximal at 1430 °C. Sintered densities higher than 95% of the theoretical one were thus obtained below 1500 °C. The bulk and additional blocking effects were characterized by impedance spectroscopy in an wet atmosphere between 150 and 600 °C. Proton conduction behavior was clearly identified. 

Ganguli, D. (2005) Chapter 7 Sol-gel derived powders and bulk ceramics, in Handbook of Sol-Gel Science and Technology Processing Characterization and Applications. Vol. I. Sol-Gel Processing (ed. K. Kozuka), Kluwer Academic Publishers, pp. 149-167. 

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