Redispersion Of Metal Oxide Powders In Sas Solutions
Z.M. Yaremko, L.B Fedushynska, O.I. Kukil
Department of Chemistry, Lviv Ivan Franko National University, Ukraine
Production of metal oxide powders and sphere of their application have been expanding on the regular basis. The significant number of disperse oxides are used for obtaining composite materials with the required set of properties. Even distribution of particles of highly dispersed powders in disperse medium is among one of the problems that occur at producing such materials.
The issues of securing a homogenous coagulation structure of disperse systems and preserving parameters of molding mixtures that are used in technological processes of producing materials are being discussed in the report. Coagulation structure of dispersed systems is formed a result of such physical-chemical phenomena as wetting, redispersion and powder particles stabilization. The degree of development of these physical-chemical phenomena in the systems that are obtained by mixing powders of fluid disperse media is determined by balanced action of the relevant factors. Namely, for wetting it’s balance of specific surface energies; for redispersion – it is balance of external forces and forces of interparticle interaction; for stabilization – it is balance of long-range surface forces.
The analysis of surface force and interparticle force balance has demonstrated that aggregation index in dispersed systems where the size of particles is less than 10 mkm has values higher than 1. In this situation the conditions for partial redispersion of metal oxides are created. The report contains results of researching redispersion of powders of aluminum, titanium and silicone oxides in solutions and at SAS of different nature. The factors that have the biggest impact on the degree of redispersion have been determined.
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