Hydrotermální syntéza oxidu ceričitého dopovaného prvky vzácných zemin

Hydrothermal Synthesis of Ceria Doped by Rare Earth Elements

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The hydrothermal synthesis of cerium oxide doped by Gd3+, Sm3+ and Y3+ ions was studied. The ractions were held at temperatures of 200-250C and pressures of 150-200 bars in the presence of these bases: hydrazine, monoethanolamine, triethanolamine or ammonium hydroxide. The reaction product – cerium oxide doped by yttrium, samarium or gadolinium had the cubic crystal lattice. The size of crystallites was in the range of 5-200 nm. The crystallites formed particles with the mean size of 10-200 nm. Cerium oxide powders were shaped by uniaxial pressing and sintered at a temperature of 1500 C. Density of the sintered ceramics was in the range of 83-95 % of theoretical value and the size of the grains was in the range of 1-5 ěm. The attained results have showed that the hydrothermal synthesis is aplicable for preparations of nanocrystalline cerium oxide doped with rare elements without necessity of the high temperature calcination.

Byla studována hydrotermální syntéza oxidu ceričitého dopovaného Gd3+, Sm3+ and Y3+. Reakce probíhaly při teplotách 200-250 C a tlaku 150-200bar v přítomnosti těchto bazí:hydrazine, monoethanolamine, triethanolamine or ammonium hydroxide. Reakční produkty:oxidy ceričité dopované yttriem, samariem a gadoliniem měly kubickou strukturu, velikost krystalitů 5-200nm a velikost částic v rozmezí 10-200 nm. Produkt byl uniaxialne lisován a slinut při 1500 C. Hustota slinuté keramiky byla v rozpětí 83-95 % TD a velikost zrn byla v rozmezi 1-5 ěm. Získané výsledky ukazují, že hydrotermální syntéza je vhodná pro přípravu nanokrystalického oxidu ceričitého dopovaného prvky vzácných zemin bez nutnosti vysokoteplotní kalcinace.

The hydrothermal synthesis of cerium oxide doped by Gd3+, Sm3+ and Y3+ ions was studied. The ractions were held at temperatures of 200-250C and pressures of 150-200 bars in the presence of these bases: hydrazine, monoethanolamine, triethanolamine or ammonium hydroxide. The reaction product – cerium oxide doped by yttrium, samarium or gadolinium had the cubic crystal lattice. The size of crystallites was in the range of 5-200 nm. The crystallites formed particles with the mean size of 10-200 nm. Cerium oxide powders were shaped by uniaxial pressing and sintered at a temperature of 1500 C. Density of the sintered ceramics was in the range of 83-95 % of theoretical value and the size of the grains was in the range of 1-5 ěm. The attained results have showed that the hydrothermal synthesis is aplicable for preparations of nanocrystalline cerium oxide doped with rare elements without necessity of the high temperature calcination.

hydrothermal synthesis, ceria, electrical properties

01.01.2003

Jožef Stefan Institute

Beograd

Abstract Book

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