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Solubility of Platinum and Rhodium in Lime–Alumina–Silica Melts at 1700 K
Author(s) -
Dable Pierre,
Allibert Michel,
Poignet Jean Claude,
Amosse Jean
Publication year - 2001
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2001.tb00796.x
Subject(s) - rhodium , platinum , solubility , ternary operation , oxide , metal , inorganic chemistry , chemistry , lime , materials science , analytical chemistry (journal) , catalysis , metallurgy , computer science , programming language , biochemistry , chromatography
Three oxide melts of composition 10‐20‐70, 30‐13‐57, and 40‐20‐40 (wt%) in the ternary system CaO–Al 2 O 3 –SiO 2 were equilibrated at 1700 K in platinum or platinum–rhodium boats, under oxygen partial pressures ( P O2 ) ranging from 10 −13 to 1 atm, and fixed by various gaseous mixtures (H 2 /H 2 O, CO/CO 2 , and Ar/O 2 ). The melts were analyzed for platinum and rhodium content after quenching. The complex dependence of solubility of these elements with P O2 was explained by their speciation. Chronopotentiometric measurements confirmed the passivation of the metallic boats. For increased P O2 , this speciation followed the series Pt, PtO, PtO 2 or RhO for the solid phases covering the metallic boats and Pt 0 , Pt 2+ , Pt 4+ , Pt 6+ or Rh 0 , Rh 2+ , Rh 3+ , Rh 4+ in solution in the oxide melt. The predominance diagrams were determined for the three compositions in the ternary system.