Colloid systems and wetting agents; subcombinations thereof; pro – Continuous liquid or supercritical phase: colloid systems;... – Aqueous continuous liquid phase and discontinuous phase...
Reexamination Certificate
2007-03-27
2009-08-04
Metzmaier, Daniel S (Department: 1796)
Colloid systems and wetting agents; subcombinations thereof; pro
Continuous liquid or supercritical phase: colloid systems;...
Aqueous continuous liquid phase and discontinuous phase...
C524S403000, C106S014120, C106S286100, C252S30140P
Reexamination Certificate
active
07569613
ABSTRACT:
The invention concerns an aqueous colloidal dispersion of isotropic particles of a phosphate of at least one rare earth and is characterized in that it comprises either a complexing agent with a pK (cologarithm of the dissociation constant of the complex formed by the complexing agent and said rare earth) of more than 2.5; or an anion of a monobasic acid, soluble in water and with a pKa in the range 2.5 to 5; or said complexing agent and/or said anion of a monobasic acid. In the case of cerium and lanthanum, the mean particle size is at most 20 nm. The dispersions can have a degree of colloid agglomeration of less than 40%.This dispersion can be prepared by forming an aqueous mixture comprising at least one rare earth salt and the complexing agent or monobasic acid anion; by adding a base then phosphate ions to the mixture formed; and heating the mixture obtained. A precipitate is obtained that is re-dispersed in water.
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Boakye et al: “Porous Aluminum Oxide and Lanthanum Phosphate Fiber Coatings”, Proceedings of the 1996 20th Annual Conf. on Composites Advanced Ceramics, Materials and Structures BI Cocoa Beach, FL., Janh 1-1996, vol. 17, No. 4, 1996, pp. 53-60; XP 00212977 Ceram. Eng. Sci Proc; Ceram. Eng. & Sci. Proceedings 1996 American Ceramic SRC.
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Buchanan Ingersoll & Rooney P.C.
Metzmaier Daniel S
Rhodia Electronics & Catalysis
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