| Abstrakt: |
1.A study was made, involving determinations of the resistance to agglomeration of suspensions by means of FÉK-M photoelectrocolorimeters and Figurovskii's balance, with the aim of evaluating the suitability of various organic dispersing media for the sedimentation analysis of aluminum powders. Sedimentation tests on powders with Figurovskii's balance give the most reliable particle size distribution data because the method employed allows for the viscosity and density of the dispersing medium.2.It was found that aluminum powder remains agglomerated in nonpolar liquids (benzene, toluene, xylene, carbon tetrachloride). In cyclohexanone and butyl, isopropyl, and ethyl (under 92%) alcohols, partial deagglomeration of aluminum powder occurs. The best resistance to agglomeration of suspensions is obtained in concentrated ethyl alcohol and acetone. It is shown, however, that acetone is not a satisfactory dispersing medium. The most effective medium for the dispersion of aluminum powders is concentrated (not less than 92%) ethyl alcohol.3.A study was made also of the effect of concentration upon the resistance to agglomeration of suspensions for aluminum powders of various degrees of fineness. It was established that, the finer the powder, the lower is the limit of permissible aluminum suspension concentration. For aluminum powders with specific surfaces of 0.2–0.4 g/m2, a suspension concentration of 0.5% is permissible. For powders with specific surfaces of more than 0.4 m2/g, the suspension concentration should not exceed 0.4%. |
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