Dependence of metal contact exchange dynamics on electrochemical parameters of electrode processes

Effect of kinetic parameters of electrode processes on the growth dynamics and structural characteristics of the friable metal deposit, which forms via its contact deposition from an aqueous solution, is studied. A model concept is based on the electrochemical processes proceeding at the metal/solution interface. Dependences of the deposition dynamics and deposit characteristics on the exchange currents of depositing and dissolving metals and on the hydrogen exchange currents at the surfaces of both metals are studied.     

Modeling Structural Changes in the Deposit during Galvanostatic Electrolysis and Contact Deposition of Metals

The crystallization of dendritic deposits during a galvanostatic electrolysis and a contact deposition of metals from aqueous solutions is modeled. Structural changes in a deposit are characterized by its distribution by radii of apexes of growing dendrites. The calculation is carried out by solving a set of differential equations by the Runge–Kutta method within the Mathcad Plus 6 package. The reduction of metals with different exchange currents during electrolysis and with different exchange currents of the component being reduced during cementation is considered. The calculated results qualitatively conform to available experimental data.     

The Synthesis and Crystal Structures of New Condensed Phosphates of Manganese

Abstract

This work deals with the synthesis of condensed phosphates of Mn(II), Mn(III), and also their combinations with Na, Cs. The reaction of MnO₂ with molten polyphosphoric acids, partially neutralized with carbonates of Na and Cs is used. In the course of reaction of MnO₂ with molten polyphosphoric acids, Mn(IV) is reduced to Mn(III) or/and Mn(II). The ratio Mn(III)/Mn(II) depends on the conditions of synthesis (temperature, time, presence of oxidants or reductants etc.). By varying these parameters we obtained 7 new manganese phosphates and determined their structures.