Abstract: After a reducing agent is added to a water reaction system containing silver ions to deposit silver particles by reduction, the silver particles are dried to obtain a silver powder which is heat-treated at a temperature of higher than 100° C. and lower than 400° C. The silver powder thus heat-treated has a maximum coefficient of thermal expansion of not greater than 1.5% at a temperature of 50° C. to 800° C., and has no heating peak when the silver powder is heated from 50° C. to 800° C. The silver powder has an ignition loss of not greater than 1.0% when the silver powder is ignited until the weight of the silver powder is constant at 800° C. The silver powder has a tap density of not less than 2 g/cm3 and a BET specific surface area of not greater than 5 m2/g.

Abstract: After a reducing agent is added to a water reaction system containing silver ions to deposit silver particles by reduction, the silver particles are dried to obtain a silver powder which is heat-treated at a temperature of higher than 100° C. and lower than 400° C. The silver powder thus heat-treated has a maximum coefficient of thermal expansion of not greater than 1.5% at a temperature of 50° C. to 800° C., and has no heating peak when the silver powder is heated from 50° C. to 800° C. The silver powder has an ignition loss of not greater than 1.0% when the silver powder is ignited until the weight of the silver powder is constant at 800° C. The silver powder has a tap density of not less than 2 g/cm3 and a BET specific surface area of not greater than 5 m2/g.

Abstract: Chalcogen compound powder containing Cu—In—Ga—Se and having an average particle diameter (DSEM) of 80 nm or less and a low content of carbon is obtained by forming a mixed solvent by mixing together at least any one of a mixture of copper salt and indium salt, a composite hydroxide of copper and indium, and a composite oxide of copper and indium, any one of selenium and a selenium compound, and a solvent having a boiling point of 250° C. or less, and heating the mixed solvent to a temperature of 220° C. to 500° C. A thin film containing Cu—In—Ga—Se and having low resistance is obtained by using paste of the chalcogen compound powder.

Abstract: The chalcogen compound has a high content of carbon and thus leads to a high resistance value. Chalcogen compound powder containing Cu—In—(Ga)—Se and having an average particle diameter (D50) of less than 0.5 ?m and a carbon content of 0.2% or less by mass in the powder is obtained in a way that metal hydroxide powder having an average primary particle diameter of 0.3 ?m or less, and one or more kinds selected from a group consisting of selenium and selenium compounds are heated to 220° C. or more in a reducing gas.

Abstract: After a reducing agent is added to a water reaction system containing silver ions to deposit silver particles by reduction, the silver particles are dried to obtain a silver powder which is heat-treated at a temperature of higher than 100° C., and lower than 400° C. The silver powder thus heat-treated has a maximum coefficient of thermal expansion of not greater than 1.5% at a temperature of 50° C. to 800° C., and has no heating peak when the silver powder is heated from 50° C. to 800° C. The silver powder has an ignition loss of not greater than 1.0% when the silver powder is ignited until the weight of the silver powder is constant at 800° C. The silver powder has a tap density of not less than 2 g/cm3 and a BET specific surface area of not greater than 5 m2/g.

Abstract: A ferromagnetic iron alloy powder for a magnetic recording medium is composed of acicular iron-base particles of an average major axis length (X) of not less than 20 nm and not greater than 80 nm and have oxygen content of not less than 15 wt % and coercive force (Hc) of not less than [0.0036 X3?1.1 X2+110 X?1390 (Oe)] (where X is average major axis length expressed in nm). The ferromagnetic iron alloy powder is obtained by reacting metal powder composed of acicular iron-base particles having an average major axis length of not less than 20 nm and not greater than 80 nm with pure water in substantial absence of oxygen to form a metal oxide film on the particle surfaces. Optionally, the particles can be reacted with a weak oxidizing gas by a wet or dry method.

Abstract: A magnetic powder for magnetic recording is provided that has improved properties suitable for a magnetic recording medium used with a high-sensitivity read head utilizing an MR device. The magnetic powder is composed of iron-base acicular particles containing Co, Al, R (rare earth elements, including Y) and oxygen within the ranges of Co/Fe=10–50 at. %, dissolved Al/(Fe+Co)=5–50 at. %, R/(Fe+Co)=2–25 at.

Abstract: After a reducing agent is added to a water reaction system containing silver ions to deposit silver particles by reduction, the silver particles are dried to obtain a silver powder which is heat-treated at a temperature of higher than 100° C. and lower than 400° C. The silver powder thus heat-treated has a maximum coefficient of thermal expansion of not greater than 1.5% at a temperature of 50° C. to 800° C., and has no heating peak when the silver powder is heated from 50° C. to 800° C. The silver powder has an ignition loss of not greater than 1.0% when the silver powder is ignited until the weight of the silver powder is constant at 800° C. The silver powder has a tap density of not less than 2 g/cm3 and a BET specific surface area of not greater than 5 m2/g.

Abstract: A spherical silver powder which has a good dispersibility and which is capable of obtaining a good degree of sintering even if it is used for forming a paste to be fired at a low temperature of 600° C. or less to form a conductor. An aqueous solution containing a reducing agent is added to a water reaction system containing silver ions, to deposit silver particles by reduction, to produce a spherical silver powder which has a shrinkage of 5 to 15% at 500° C., a shrinkage of 10 to 20% at 600° C., a mean particle size of not greater than 5 ?m, a tap density of not less than 2 g/cm3, and a BET specific surface area of not greater than 5 m2/g.

Abstract: A spherical silver powder has a good dispersibility and is capable of obtaining a good degree of sintering even if used for forming a paste to be fired at a low temperature of 600° C. or less to form a conductor. An aqueous solution containing a reducing agent is added to a water reaction system containing silver ions, to deposit silver particles by reduction, to produce a spherical silver powder wherein a ratio (Dx/BET) of a crystallite diameter Dx (nm) to a BET specific surface area (m2/g) is in the range of from 5 to 200 and which has a crystallite diameter of not greater than 40 nm, a mean particle size of not greater than 5 ?m, a tap density of not less than 2 g/cm3, and a BET specific surface area of not greater than 5 m2/g.

Abstract: A ferromagnetic iron alloy powder for a magnetic recording medium is composed of acicular iron-base particles of an average major axis length (X) of not less than 20 nm and not greater than 80 nm and have oxygen content of not less than 15 wt % and coercive force (Hc) of not less than [0.0036 X3?1.1 X2+110 X?1390 (Oe)] (where X is average major axis length expressed in nm). The ferromagnetic iron alloy powder is obtained by reacting metal powder composed of acicular iron-base particles having an average major axis length of not less than 20 nm and not greater than 80 nm with pure water in substantial absence of oxygen to form a metal oxide film on the particle surfaces. Optionally, the particles can be reacted with a weak oxidizing gas by a wet or dry method.

Abstract: A ferromagnetic iron alloy powder for a magnetic recording medium is composed of acicular iron-base particles of an average major axis length (X) of not less than 20 nm and not greater than 80 nm and have oxygen content of not less than 15 wt % and coercive force (Hc) of not less than [0.0036 X3?1.1 X2+110 X?1390 (Oe)] (where X is average major axis length expressed in nm). The ferromagnetic iron alloy powder is obtained by reacting metal powder composed of acicular iron-base particles having an average major axis length of not less than 20 nm and not greater than 80 nm with pure water in substantial absence of oxygen to form a metal oxide film on the particle surfaces. Optionally, the particles can be reacted with a weak oxidizing gas by a wet or dry method.

Abstract: A ferromagnetic iron alloy powder for a magnetic recording medium is composed of acicular iron-base particles of an average major axis length (X) of not less than 20 nm and not greater than 80 nm and have oxygen content of not less than 15 wt % and coercive force (Hc) of not less than [0.0036 X3−1.1 X2+110 X−1390 (Oe)] (where X is average major axis length expressed in nm). The ferromagnetic iron alloy powder is obtained by reacting metal powder composed of acicular iron-base particles having an average major axis length of not less than 20 nm and not greater than 80 nm with pure water in substantial absence of oxygen to form a metal oxide film on the particle surfaces. Optionally, the particles can be reacted with a weak oxidizing gas by a wet or dry method.

Abstract: A magnetic powder for magnetic recording is provided that has improved properties suitable for a magnetic recording medium used with a high-sensitivity read head utilizing an MR device. The magnetic powder is composed of iron-base acicular particles containing Co, Al, R (rare earth elements, including Y) and oxygen within the ranges of Co/Fe=10-50 at. %, dissolved Al/(Fe+Co)=5-50 at. %, R/(Fe+Co)=2-25 at.