Determining the Lanthanum Chromite Zeta Potential in Aqueous Media

Abstract

Lanthanum Chromite may used as interconnect for SOFC’s applications due its particular intrinsic properties as stability in both oxidant and reducing environments and electrical conductivity. However to manufacture these devices that generally present complex shapes as grooved plates and fine pipes, they are necessary the use of the conformation techniques such as screen printing, slip casting, tape casting, extrusion moulding, etc. that are related with colloid processing. Independent of the processing techniques chosen the control of the suspension conditions is important to obtain reproducibility and homogeneous products as final result. In this sense, all contribution to understand the behaviour of the LaCrO3 fine particles in liquid suspension as the surface state using the Zeta’s Potential concepts may supplies information by the forecast of the behaviour during the shaped processing. The aqueous suspensions behaviour was studied utilizing doped lanthanum chromite powders, attained by combustion synthesis. The eletrophoretic mobility measurements of particles in suspension, prepared with the different conditioned powders were made. The electrolyte compositions as function of the pH varying from 2 to 12 were tested. The Zeta potentials and the stability conditions for stable suspensions prepared were determined. The viscosity curves are also appraised.

Cromito de lantânio: material para interconectores de células a combustível de óxido sólido - uma revisão

“…Por outro lado, a redução de mobilidade eletroforética para pH inferiores a 3,0 é justificada pela dissolução do cromo superficial com o aumento da força iônica [119]. Os valores de pH onde ocorre a isoeletricidade, identificados para as diversas composições de cromito de lantânio, são apresentados na Tabela II. O comportamento superficial, valores de potencial zeta e ponto isoelétrico, não se alteram com o tamanho das partículas [14,124], conforme apresentado na Fig. 3.…”