Pore Forming Agent–Assisted Fabrication of Porous Platinum Vent Frits and Their Suitability Evaluation for Radioisotope Power Sources

Abstract

Disc-shaped porous platinum sintered frits were fabricated employing a pore forming agent (PFA) via a powder-metallurgical process. Porous vent frits using several platinum-PFA compositions were prepared after characterizing the starting materials (platinum and PFA powders) for particle size (D50) and distribution (D10 to D90), morphology, Brunauer-Emmet-Teller surface area, density (apparent and tap), etc. The sintered platinum vent frits were extensively characterized to evaluate their suitability for application in terms of surface microstructure analysis by scanning electron microscopy, helium/air permeability parameters, and particulate filtration characteristics. This paper reports for the first time on the measurement of retention efficiency of vent frits for particulate sizes 0.3, 0.5, and 1 µm. The platinum frits made using 10 and 20 vol % PFA were found to be suitable as a vent hole filter for radioisotope power sources.

Keywords:

• Radioisotope power sources
• platinum vent frit
• pore forming agent
• gas permeability
• particulate efficiency

Acknowledgments

The authors are grateful to colleagues from the Oxide Fuel section, Maintenance section, Utility services, and other sections of the Fuel Fabrication-Integrated Nuclear Recycle Plants (Operation), FF-INRP(O), Tarapur, for extending their help in the preparation of experimental setups.

Disclosure Statement

The authors declare that there are no relevant financial or nonfinancial competing interests to report.

Notes

^a D50 is a median particle diameter corresponding to the 50th percentile of the cumulative undersize distribution (here by volume).

^b The D10 to D90 range corresponds to particle diameters between the 10th and 90th percentile of the cumulative undersize distribution (here by volume).

^c Green density is the geometrical density of cold-compacted discs before sintering, expressed in precent theoretical density (%TD).

^d Sintered density is the geometrical density of the discs after sintering, expressed in %TD.

^e Diffusion length is the average distance traveled by an atom under the sintering process.

^f The LPF is the fraction of particles leaving the filter, LPF = 1-E/100, where E is retention efficiency.