Submicron powder formation

In commercial applications of submicron powdered materials as additives, fillens, and pigments, nonagglomerated or weakly agglomerated primary particles are usually desired. Quantitative, predictive methods for describing neck formation and the nature of the bonds between particles are not available. In the ab,sence of proven methods, we di.scu.ss some guidelines that may serve as a starting point for future research. 

Decomposition of Ti(0-iC 3117)4 dissolved in supercritical isopropanol leads to the formation of titanium oxide. The reaction is studied in the temperature range 531 to 568 K under 10 MPa and a mechanism is proposed. The obtained kinetic results are further used to optimize a continuous reactor producing submicronic TiC>2 powder at a laboratory pilot scale. 

Polymer processing with supercritical fluids can result in the formation of very fine powders, fine fibers, microspheres, microballoons, and thin films. As indicated in Table 24.6 very fine particles with submicron diameters and ultra-thin films (6 nm) were obtained using RESS. Tepper and... 

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