The present invention provides a powder surface treatment method comprising (i) a step for mixing 0.001-20 parts by mass of a surface treating agent composition with 100 parts by mass of a power, and (ii) a step for adding an acidic liquid, followed by mixing, wherein the surface treating agent composition contains (a)-(d) below: (a) one or more selected from among an N-acyl amino acid having a carbon chain length of C8-C22 and a salt thereof; (b) one or more selected from among monohydric and polyhydric alcohols; (c) water; and (d) one or more selected from among (dl) an amino acid having an isoelectric point of 7.5-11, and (d2) a compound which generates an ion selected from among an aluminum ion, a magnesium ion, a calcium ion, a zinc ion, a zirconia ion, and a titanium ion, in the surface treating agent composition.

The present invention provides a powder surface treatment method comprising (i) a step for mixing 0.001-20 parts by mass of a surface treating agent composition with 100 parts by mass of a power, and (ii) a step for adding an acidic liquid, followed by mixing, wherein the surface treating agent composition contains (a)-(d) below: (a) one or more selected from among an N-acyl amino acid having a carbon chain length of C8-C22 and a salt thereof; (b) one or more selected from among monohydric and polyhydric alcohols; (c) water; and (d) one or more selected from among (dl) an amino acid having an isoelectric point of 7.5-11, and (d2) a compound which generates an ion selected from among an aluminum ion, a magnesium ion, a calcium ion, a zinc ion, a zirconia ion, and a titanium ion, in the surface treating agent composition.

A method suitable for mass production of nanoparticles with a uniform particle diameter is provided. It is an object to provide a powder of the nanoparticle obtained by this method, a dispersion containing the nanoparticles, and a paste containing the nanoparticles. There is provided a method for manufacturing silver particles including the step of reducing silver in a silver solution containing a protective agent composed of an organic material and a copper component in an amount of 1 to 1,000 ppm relative to the amount of silver to obtain particles having an average particle diameter (D.sub.TEM) of 5 to 100 nm as measured using a transmission electron microscope.

A method suitable for mass production of nanoparticles with a uniform particle diameter is provided. It is an object to provide a powder of the nanoparticle obtained by this method, a dispersion containing the nanoparticles, and a paste containing the nanoparticles. There is provided a method for manufacturing silver particles including the step of reducing silver in a silver solution containing a protective agent composed of an organic material and a copper component in an amount of 1 to 1,000 ppm relative to the amount of silver to obtain particles having an average particle diameter (D.sub.TEM) of 5 to 100 nm as measured using a transmission electron microscope.

The present invention relates to platelet-shaped zinc-magnesium pigments, wherein the platelet-shaped zinc-magnesium pigments comprise the 40.8 to 67.8 mol % of zinc, 32.2 to 59.2 mol % of magnesium and 0 to 7 mol % of Mn, Li, Be, Y, Sn, Al, Ti, Fe, Cu and mixtures thereof, based in each case on the total molar amount of the elements Zn, Mg, Mn, Be, Y, Li, Sn, Al, Ti, Fe and Cu, where the molar percentages add up to 100 mol %, and the median thickness h.sub.50 of the pigments is less than 1 μm. The invention further relates to the use and production of these pigments.

The present invention relates to platelet-shaped zinc-magnesium pigments, wherein the platelet-shaped zinc-magnesium pigments comprise the 40.8 to 67.8 mol % of zinc, 32.2 to 59.2 mol % of magnesium and 0 to 7 mol % of Mn, Li, Be, Y, Sn, Al, Ti, Fe, Cu and mixtures thereof, based in each case on the total molar amount of the elements Zn, Mg, Mn, Be, Y, Li, Sn, Al, Ti, Fe and Cu, where the molar percentages add up to 100 mol %, and the median thickness h.sub.50 of the pigments is less than 1 μm. The invention further relates to the use and production of these pigments.

A silver powder, including: an organic substance on a surface of the silver powder, the organic substance containing at least one carboxyl group and at least one hydroxyl group in one molecule of the organic substance, wherein a BET specific surface area of the silver powder is 0.1 m.sup.2/g or more but 2.0 m.sup.2/g or less, and wherein a cumulative 50% point of particle diameter (D.sub.50) of the silver powder in a volume-based particle size distribution of the silver powder as measured by a laser diffraction particle size distribution analysis is 0.1 μm or more but 6.0 μm or less, and a ratio of [(D.sub.90−D.sub.10)/D.sub.5o] is 3.0 or less, where D.sub.50 is the cumulative 50% point of particle diameter, D.sub.90 is a cumulative 90% point of particle diameter of the silver powder, and D.sub.10 is a cumulative 10% point of particle diameter of the silver powder.

A silver powder, including: an organic substance on a surface of the silver powder, the organic substance containing at least one carboxyl group and at least one hydroxyl group in one molecule of the organic substance, wherein a BET specific surface area of the silver powder is 0.1 m.sup.2/g or more but 2.0 m.sup.2/g or less, and wherein a cumulative 50% point of particle diameter (D.sub.50) of the silver powder in a volume-based particle size distribution of the silver powder as measured by a laser diffraction particle size distribution analysis is 0.1 μm or more but 6.0 μm or less, and a ratio of [(D.sub.90−D.sub.10)/D.sub.5o] is 3.0 or less, where D.sub.50 is the cumulative 50% point of particle diameter, D.sub.90 is a cumulative 90% point of particle diameter of the silver powder, and D.sub.10 is a cumulative 10% point of particle diameter of the silver powder.

A silver powder, including: an organic substance on a surface of the silver powder, the organic substance containing at least one carboxyl group and at least one hydroxyl group in one molecule of the organic substance, wherein a ratio of (Casson yield value/BET specific surface area) is 500 or less, where the Casson yield value is a Casson yield value of a conductive paste and the BET specific surface area is a BET specific surface area of the silver powder, where the conductive paste has a composition in which the silver powder is 86% by mass, a glass fit is 1% by mass, ethyl cellulose is 0.6% by mass, texanol is 10.5% by mass, and zinc oxide is 1.9% by mass, and the conductive paste is prepared by kneading the composition with a planetary centrifugal stirrer and bubble remover and dispersing with a triple roll mill.

A silver powder, including: an organic substance on a surface of the silver powder, the organic substance containing at least one carboxyl group and at least one hydroxyl group in one molecule of the organic substance, wherein a ratio of (Casson yield value/BET specific surface area) is 500 or less, where the Casson yield value is a Casson yield value of a conductive paste and the BET specific surface area is a BET specific surface area of the silver powder, where the conductive paste has a composition in which the silver powder is 86% by mass, a glass fit is 1% by mass, ethyl cellulose is 0.6% by mass, texanol is 10.5% by mass, and zinc oxide is 1.9% by mass, and the conductive paste is prepared by kneading the composition with a planetary centrifugal stirrer and bubble remover and dispersing with a triple roll mill.