Lifetimes of thin film AMTEC electrodes

Ryan, M. A.; Kisor, A.; Williams, Roger; Jeffries‐Nakamura, B.; O'Connor, D.

doi:10.2514/6.1994-3831

Cited by 14 publications

(6 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Lifetime characteristics of molybdenum and two preparations of Rh,W have been previously reported (Ryan, et al, 1994). A model for grain growth based on a model of coalescence of spheres was developed and applied to Mo, RhW and RhZW.…”

Section: Grain Growth Modelmentioning

confidence: 99%

“…A model for grain growth based on a model of coalescence of spheres was developed and applied to Mo, RhW and RhZW. The grain radius was correlated with electrode performance through the temperature independent exchange current, B (Williams, et al, 1990b), and B was independently correlated with electrode power (Ryan, et al, 1994). Further data have been used to confirm the applicability of that model.…”

Section: Grain Growth Modelmentioning

confidence: 99%

“…In studies of the grain growth rates of Mo, PtxW and Rh,W electrodes, an empirical correlation between grain size and exchange current expressed as B has been developed (Ryan, et al, 1994). The electrode reaction, reduction of sodium ions (Naf>, occurs at the electrode/electrolyte interface, at the perimeter of the grains.…”

Section: Relationship Of B and Grain Radiusmentioning

confidence: 99%

“…It is a sensitive probe of electrode performance, which is reflected in the overall power conversion in an AMTEC cell. A semi-empirical relationship between Power and B has been developed and previously presented (Ryan, et al, 199 I ;Ryan, et al, 1994). B can fall to -50 from a starting value of 100 with only a 10% drop in power.…”

Section: Relationship Of Power and Bmentioning

confidence: 99%

“…Coalescence of Spheres Model -Mo and R h u y The grain size of Rhl.SW was measured after 3000 hours of operation and compared with grain size computed for this temperature and time according to the model previously presented (Ryan, et al, 1994). New Mo experiments were not run.…”

Section: Grain Radiimentioning

confidence: 99%

See 4 more Smart Citations

Lifetimes of AMTEC electrodes: Molybdenum, rhodium-tungsten, and titanium nitride

Ryan¹,

Shields²,

Cortez³

et al. 2000

AIP Conference Proceedings

View full text Add to dashboard Cite

The lifetime of three types of AMTEC electrodes is predicted from the rate of grain growth in the electrode. Grain size is related to electrode performance, allowing performance to be correlated with grain growth rate. The rate of growth depends on physical characteristics of each material, including the rates of surface self-difhsion and molecule mobility along grain boundaries. Grain growth rates for molybdenum, rhodium-tungsten and titanium nitride electrodes have been determined experimentally and fit to models in order to predict operating lifetimes of AMTEC electrodes. For lifetimes of 10 years or more, Rh,W electrodes may be used at any operating temperature supportable by the electrolyte. TiN electrodes may be used in AMTEC cells only at operating temperatures under 1150 K. and Mo may be used only below 1100 K.

show abstract

Section: Grain Growth Modelmentioning

confidence: 99%

Section: Grain Growth Modelmentioning

confidence: 99%

Section: Relationship Of B and Grain Radiusmentioning

confidence: 99%

Section: Relationship Of Power and Bmentioning

confidence: 99%

Section: Grain Radiimentioning

confidence: 99%

See 3 more Smart Citations