Abstract: The present invention is directed to a method for preparing colloidal dispersions of precious metal nanoparticles selected from the group consisting of Pt, Au, Pd, Ag, Rh, Ru and mixtures or alloys thereof, and to a method for isolating such precious metal nanoparticles from these colloidal dispersions. The colloidal dispersions are prepared by reducing suitable precious metal precursor compounds in aqueous alkaline solutions at reaction temperatures between 40 and 70° C. and a pH?12.0 in the presence of polysaccharides with average molecular weights (Mw) in the range of 300,000 to 1,000,000. The precious metal nanoparticles are isolated after decomposing the polysaccharide by heating the colloidal dispersions to temperatures >80° C. The nanoparticles can be used for the manufacture of core/shell-type catalyst materials and for electronic, decorative and medical applications.

Abstract: The present invention is directed to a method for preparing colloidal dispersions of precious metal nanoparticles selected from the group consisting of Pt, Au, Pd, Ag, Rh, Ru and mixtures or alloys thereof, and to a method for isolating such precious metal nanoparticles from these colloidal dispersions. The colloidal dispersions are prepared by reducing suitable precious metal precursor compounds in aqueous alkaline solutions at reaction temperatures between 40 and 70° C. and a pH?12.0 in the presence of polysaccharides with average molecular weights (Mw) in the range of 300,000 to 1,000,000. The precious metal nanoparticles are isolated after decomposing the polysaccharide by heating the colloidal dispersions to temperatures >80° C. The nanoparticles can be used for the manufacture of core/shell-type catalyst materials and for electronic, decorative and medical applications.

Abstract: An efficient process for producing fine nickel powder, capable of metallizing the powder at low temperature to prevent its sintering, and fine nickel powder produced by the process, composed of particles having a flat shape, diameter of limited variations and uniform thickness, and suitable for internal electrodes for laminate ceramic capacitors of high electric capacity. The process comprises a step for forming a nickel compound coated with gelatin by adsorbing gelatin on preformed nickel compound particles with different size and shape (Step (A)), and another step for converting said nickel compound coated with gelatin into fine particles containing metallic nickel and nickel oxide by heating the nickel compound coated with gelatin produced in Step (A) in an inert gas atmosphere (Step (B)). It may include an additional step (Step (C)), subsequent to Step (B), for completely reducing nickel oxide in said fine particles by heating at temperature lower than that for Step (B) in a reducing gas atmosphere.

Abstract: An efficient process for producing fine nickel powder, capable of metallizing the powder at low temperature to prevent its sintering, and fine nickel powder produced by the process, composed of particles having a flat shape, diameter of limited variations and uniform thickness, and suitable for internal electrodes for laminate ceramic capacitors of high electric capacity. The process comprises a step for forming a nickel compound coated with gelatin by adsorbing gelatin on preformed nickel compound particles with different size and shape (Step (A)), and another step for converting said nickel compound coated with gelatin into fine particles containing metallic nickel and nickel oxide by heating the nickel compound coated with gelatin produced in Step (A) in an inert gas atmosphere (Step (B)). It may include an additional step (Step (C)), subsequent to Step (B), for completely reducing nickel oxide in said fine particles by heating at temperature lower than that for Step (B) in a reducing gas atmosphere.

Abstract: A semiconductor nanoparticle for use in analysis of biological samples is described. This semiconductor nanoparticle is composed of an aminodextran which is bound to at least one nanoparticle of the formula (X Y)n wherein X is selected from the group comprising Cd2+, Hg2+, and Zn2+ and combinations thereof, and Y is selected from the group comprising S2−, Se2− and Te2− and combinations thereof; and n=approximately 50 to 1000. Also provided are methods of making these semiconductor nanoparticles and methods of making conjugates composed of these semiconductor nanoparticles linked to ligands. Also described are uses for the conjugates in a variety of biological assays.

Abstract: A semiconductor nanoparticle for use in analysis of biological samples is described. This semiconductor nanoparticle is composed of an aminodextran which is bound to at least one nanoparticle of the formula (XY)n wherein X is selected from the group comprising Cd2+, Hg2+, and Zn2+ and combinations thereof, and Y is selected from the group comprising S2−, Se2− and Te2− and combinations thereof; and n=approximately 50 to 1000. Also provided are methods of making these semiconductor nanoparticles and methods of making conjugates composed of these semiconductor nanoparticles linked to ligands. Also described are uses for the conjugates in a variety of biological assays.

Abstract: A semiconductor nanoparticle for use in analysis of biological samples is described. This semiconductor nanoparticle is composed of an aminodextran which is bound to at least one nanoparticle of the formula (X Y)n wherein X is selected from the group comprising Cd2+, Hg2+, and Zn2+ and combinations thereof; and Y is selected from the group comprising S2−, Se2− and Te2− and combinations thereof; and n=approximately 50 to 1000. Also provided are methods of making these semiconductor nanoparticles and methods of making conjugates composed of these semiconductor nanoparticles linked to ligands. Also described are uses for the conjugates in a variety of biological assays.

Abstract: The invention relates to a metal sulfide dispersion used for electroplating nonconductors such as substrates used for the formation of a printed circuit board. A printed circuit board made using the dispersion could have metallized through-holes comprising electrodeposited copper on the walls of the holes with an adsorbed layer of metal sulfide particles between the circuit board base material and the copper on the walls of the through-holes. The metal sulfide is characterized by spherical particles having a mean diameter of less than 100 nanometers and a particle size distribution where less than 10 percent of the particles within the dispersion have a diameter twice that of the mean diameter of all particles within the dispersion.

Abstract: A process for the preparation of crystalline perovskite powders consisting essentially of primary particles uniform in nanometer or micrometer size and uniform and near spherical shape and of narrow size distribution, of the general formula A.sub.x (BO.sub.3).sub.y, wherein cation A is at least one metal selected from the group comprising Li.sup.+, Na.sup.+, K.sup.+, Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, Ba.sup.2+ and La.sup.3+ and B in the anion (BO.sub.3) is at least one metal selected from the group consisting of Ti.sup.4+, Zr.sup.4+, Sn.sup.4+, Hf.sup.4+, Nb.sup.5+ and Ta.sup.5+, x is equal to the valence of the anion (BO.sub.

Abstract: The adsorption of cationic dyes on nanosize negatively charged silica particles to form colored pigments is disclosed. The dyes are chemisorbed and their uptake is controlled by the strong chemical reaction between the negative surface of the adsorbent silica particles preferably with sodium counter ions and the positive charge of the dyes. The prepared pigments are useful in the formation of color films and their optical properties are described. Photoresists using nanosized pigments are also disclosed herein which are useful in making color filters for liquid crystal displays.

Abstract: The adsorption of anionic dyes on nanosize alumina modified silica particles to form colored pigments is disclosed. The dyes are chemisorbed and their uptake is controlled by the strong chemical reaction between positive surface of the absorbent and negative charge of the adsorbates. The prepared pigments are useful in the formation of color films and their optical properties are described. Photoresists using nanosized pigments are also disclosed herein which are useful in making color filters for liquid crystal displays.

Abstract: A method of making synthetic color pigments comprises synthesizing monodispersed colloidal core particles by precipitation from a solution and applying dye material to the core particles either by adsorption directly into the core particles or by adsorption or incorporation into alumina fixation shells at the surfaces of the core particles. Additional functional shells may be applied to the dyed core particles for various reasons. The pigments are useful for the coloration of various media such as printing inks and paint compositions.

Abstract: Spherical particles include a core of a polymer and a metal compound covering the polymer core. These particles may be formed by homogeneously dispersing particles of a polymeric compound in an aqueous solution of a hydrolyzable metal salt to form a uniform metal layer around the spherical particles. The spherical particles can also include a core of carbon and a metal compound covering the carbon core or the particles can have a hollow core prepared by heating spherical polymer particles coated with a metal compound to a temperature of 150.degree. C. or higher in the presence of oxygen to completely decompose the polymeric compound. These spherical particles are useful in electronic materials, magnetic materials and the like.

Abstract: A method of making synthetic color pigments comprises synthesizing monodispersed colloidal core particles by precipitation from a solution and applying dye material to the core particles either by adsorption directly into the core particles or by adsorption or incorporation into alumina fixation shells at the surfaces of the core particles. Additional functional shells may be applied to the dyed core particles for various reasons. The pigments are useful for the coloration of various media such as printing inks and paint compositions.

Abstract: Whitener pigment particles that offer good hiding power consist of particles having a uniform shape (preferably spherical) and varying only slightly in dimension. The particles consist of an inexpensive, readily manufacturable core material which is surrounded by one or more thin, concentric layers or shells, one of which is titania. The core provides the central mechanical support for the shells. In addition to the titania shell, layers can be added to provide compatibility with the carrier in which the particles are dispersed and promote phase transformation. Also described is a production method and apparatus for generating large quantities of the particles.

Abstract: An improved process for the preparation of monodispersed spherical colloidal particles from rare earth salts is disclosed. These colloidal particles are obtained in this process by homogeneous precipitation techniques involving the forced hydrolysis of rare earth salts in aqueous media. More specifically, this process initially involves the formation of hydrolyzed cations which are precursors or intermediate to precipitation of the desired colloidal particle. The objective in the formation of this precursor species is to reach critical supersaturation concentration of this particle forming species so that only one burst of nuclei occurs. Colloidal particle formation is then effected by diffusion of solutes onto the existing nuclei. The improvements of this process reside, in part, in the ability to control the kinetics of formation of this intermediate species. Such control permits the formation of colloidal dispersions having very narrow particle size distribution.

Abstract: Titanates of barium, strontium, or mixed barium and strontium consisting essentially of solid, non-aggregated particles having diameters ranging from 0.05 to 1 micron and a narrow particle size distribution expressed by the polydispersity index, dw/dn, not greater than 1.20, where dw is the weight average diameter and dn is the number average diameter, said particles being essentially perfectly spherical with a total mean axial ratio of at least 0.93. These titanates are prepared by a process which comprises precipitating of a peroxidic precursor having the same morphological characteristics of the titanates. The peroxidic precursor is obtained by heating an alkaline solution comprising a complex of a titanium compound with a peroxidic compound, an M.sup.2+ compound, wherein M is Ba, Sr or mixtures thereof, and a compound Z capable of complexing with the M.sup.

Abstract: Spherical particles having sizes below 1 .mu.m, or at maximum of 3.04 .mu.m, a narrow size size distribution consisting, or consisting essentially, of TiO.sub.2 coated by a uniform layer having a thickness up to 400 .ANG. consisting essentially .alpha.-, or .gamma.-Fe.sub.2 O.sub.3, or magnetite, or mixtures thereof, said particles being prepared by a process consisting, or consisting essentially, in the precipitation of the oxide from Fe (III) salt solutions on the surface of solid pre-formed TiO.sub.2 particles having a narrow size distribution and a number average diameter below 1 .mu.m or .ltoreq.3 .mu.m, the Fe (III) concentration being .ltoreq.40% by weight calculated on TiO.sub.2, the pH of the suspension ranging from 1.0 to 2.8, extremes excluded, by heating the suspensions to temperatures of from 80.degree. to 100.degree. C., and by aging them under such conditions for at least 30 minutes.

Abstract: Titanium dioxide, in the form of discrete, solid substantially spherical particles of a substantially uniform shape and size, is obtained by providing an aerosol comprising discrete liquid particles of a hydrolyzable titanium compound, contacting the aerosol with water vapor in dynamic flow to hydrolyze the liquid titanium (IV) compound to titanium dioxide, and recovering the desired product.