The equilibrium between Na-β- and Na-β′′-alumina as a function of the phase composition

Determination of the potassium activity in the heterogeneous phase system K-beta-Al2O3/borate glass, MeO/Me

“…In analogy to the behaviour of Na-(b + b 00 )-Al 2 O 3 [5], the position of equilibrium (5) must be assumed to be a function of the potassium activity in the ambience of the KBA phase. It holds that…”

“…As long as the glass behaves inert against KBA and only plays the role of a solvent for NiO and FeO formed at the surface of the alloy, the potassium oxide activity is determined by the equilibrium between the constituent phases of KBA according to equation (5). Therefore it holds ln a 000…”

Revision of the data on the standard Gibbs free energy of formation of sodium zirconate

“…Na-b-Al 2 O 3 and Na-b 00 -Al 2 O 3 [22]. As a consequence of equation (2), it follows for the oxygen pressure p O 2 at each of the electrode sides:…”

“…Usually NBA may be expected to represent a phase mixture with univariant behaviour [22]. However, this is true only if certain conditions are fulfilled.…”

Characterization of the Phase Mixture Comprising Sodium Hafnate and Hafnia

“…The sodium activity in turn results from the Na 2 CO 3 /gas equilibrium according to Equation (1) and is equalized throughout the solid bodies of Na 2 CO 3 , NBA and NHO due to the electronic short-circuit. [9] As a prerequisite, sodium has to be mobile in these phases. That the assumption of finite sodium ion mobility is justified for Na 2 CO 3 and NBA is well proven experimentally by the extensive utilization of these phases in solid-state CO 2 sensors (e.g.…”