Hydrothermal method for preparing large single crystals of scandium, yttrium, and lanthanide sesquioxides
OwnerJoseph Kolis, Colin D. McMilleninventors
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Abstract
Scandium, yttrium, and lanthanide sesquioxide crystals having the formula Ln2O3, wherein Ln is selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, with or without an activator ion, are made by a hydrothermal method for a variety of end-use applications
Claims13
A method for growing lanthanide oxide crystals having the formula Sc2O3, comprising the steps of:
- dispersing Sc2O3 powder in an aqueous solution having an hydroxide ion concentration of from about 1 to about 30 molar;
- and
- subjecting the solution to a temperature of from about 450° C. to about 700° C. and a pressure of from about 4 kpsi to about 30 kpsi.
A method for growing lanthanide oxide crystals having the formula Ln2O3, wherein Ln is selected from the group consisting of the lanthanide elements ranging from La to Lu and Y, comprising the steps of:
- dispersing Ln2O3 powder in an aqueous solution having an hydroxide ion concentration of from about 1 to about 30 molar;
- and
- subjecting the solution to a temperature of from about 640° C. to about 750° C. and a pressure of from about 15 kpsi to about 40 kpsi.
A method for growing a lanthanide oxide crystal having the formula LnxLn′(2-x)O3 wherein Lnx is selected from the group consisting of Sc, Y, Gd, La and Lu, and wherein Ln′ is selected from the group consisting of Er, Pr, Yb, Nd, Ho, Tm, Th, Cr, Ti and any other lanthanide or transition metal having a 3+ ionic charge, comprising the steps of:
- dispersing LnxLn′(2-x)O3 powder in an aqueous solution having an hydroxide ion concentration of from about 1 to about 20 molar;
- and
- subjecting the solution to a temperature of from about 450° C. to about 700° C. and a pressure of from about 10 kpsi to about 30 kpsi.
A method for growing a lanthanide oxide crystal having the formula Ln2O3 wherein Ln is selected from the group consisting of Sc, Y, La, Lu, and Gd, comprising the steps of:
- providing a pressure vessel having a growth region and a nutrient region;
- providing a seed crystal having the formula Ln2O3 wherein Ln is selected from the group consisting of Sc, Y, La, Lu, and Gd;
- positioning the seed crystal in the growth region of the pressure vessel;
- providing a medium comprising a nutrient and a mineralizer in the nutrient region, the nutrient comprising powdered or microcrystalline Ln2O3 wherein Ln is the Ln of the seed crystal, the mineralizer comprising hydroxide ions;
- and
- heating and pressurizing the vessel such that a growth temperature is produced in the growth region, a nutrient temperature is produced in the nutrient region, and a temperature gradient is produced between the growth region and the nutrient region, whereby growth of the crystal is initiated, the growth temperature ranging from about 450° C. to about 650° C., the nutrient temperature ranging from about 500° C. to about 750° C., the nutrient temperature being higher than the growth temperature and the pressure ranging from about 4 kpsi to about 30 kpsi.
A method for growing a lanthanide oxide crystal having the formula LnxLn′(2-x)O3 wherein Ln is selected from the group consisting of Sc, Y, La, Lu, and Gd, and wherein Ln′ is selected from the group consisting of Er, Pr, Yb, Nd, Ho, Tm, Tb, Cr, Ti and any other lanthanide or transition metal having a 3+ ionic charge, comprising the steps of:
- providing a pressure vessel having a growth region and a nutrient region;
- providing a seed crystal having the formula Ln2O3 or LnxLn′(2-x)O3 wherein Ln is selected from the group consisting of Sc, Y, La, Lu, and Gd;
- positioning the seed crystal in the growth region of the pressure vessel;
- providing a medium comprising a nutrient and a mineralizer in the nutrient region, the nutrient comprising powdered or microcrystalline LnxLn′(2-x)O3 wherein Ln and Ln′ are the Ln and Ln′ of the seed crystal, the mineralizer comprising hydroxide ions;
- and
- heating and pressurizing the vessel such that a growth temperature is produced in the growth region, a nutrient temperature is produced in the nutrient region, and a temperature gradient is produced between the growth region and the nutrient region, whereby growth of the crystal is initiated, the growth temperature ranging from about 450° C. to about 650° C., the nutrient temperature ranging from about 500° C. to about 750° C., the nutrient temperature being higher than the growth temperature and the pressure ranging from about 4 kpsi to about 30 kpsi.
Dependencies are inferred from the claim text.