Surface tension-induced convection as a particle aggregation mechanism

• Published in: Journal of colloid and interface science Vol. 151; no. 2; pp. 477 - 489
• Main Authors: Teschke, O, Kleinke, M.U, Tenan, M.A
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.07.1992; Elsevier
• Subjects: Chemistry; Electrochemistry; Exact sciences and technology; General and physical chemistry; Miscellaneous; Study of interfaces; Scanning electron microscopy; Electrolyte solution; Electrode electrolyte interface; Transition metal; Iron; Contact angle; Particle suspension; Experimental study; Acidic solution; Surface structure; Sulfuric acid; Aggregation; Electrodes; Iron Sulfates; Wall effect
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/0021-9797(92)90495-8

In the present work it is shown that convection—diffusion processes cause a peculiar morphology of precipitated iron sulfate on the metal surface. The calculated solution velocity distribution at the electrode surface shows a pattern of square cells. This fluid motion accelerates the aggregation of particles into a preferential square-cell geometry, which was observed on the samples. The samples, which were prepared using a freeze-drying technique, show that the square pattern cell sizes have the same functional dependence on sulfuric acid concentration as on the interfacial tension variation. The stability condition for cell pattern formation and also turbulence threshold are discussed as are the wall effects on the cell nonuniformity distribution.