Method for preparing surface-modified nickel powder
AssigneeMitsui Mining & Smelting Co., Ltd.
InventorsTakayuki Araki, Takashi Mukuno
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AssigneeMitsui Mining & Smelting Co., Ltd.
InventorsTakayuki Araki, Takashi Mukuno
Estimating the term…
Herein disclosed is surface-modified nickel fine powder in which a precursor of barium titanate having a perovskite structure and consisting of a reaction product of a soluble titanium-containing compound and a soluble barium-containing compound is adhered to the surface of individual nickel fine particles, wherein the fine powder shows X-ray diffraction peaks of nickel and is free of any peak of barium titanate having a perovskite structure in the X-ray diffraction pattern determined by the X-ray diffraction method, but the fine powder shows X-ray diffraction peaks of both nickel and barium titanate having a perovskite structure in the X-ray diffraction pattern after the fine powder is subjected to a heat-treatment at a temperature of not less than 400° C. The nickel fine powder has a small heat shrinkage factor upon firing and improved resistance to oxidation. The powder permits the inhibition of any such phenomenon that nickel is oxidized and the oxidized nickel penetrates into a ceramic dielectric material during firing. The powder is suitable for use as a material for a conductive paste and, in particular, for forming a conductive paste used in making a multilayer ceramic capacitor.
Surface-modified nickel fine powder in which a precursor of barium titanate having a perovskite structure and consisting of a reaction product of a soluble titanium-containing compound and a soluble barium-containing compound is adhered to the surface of individual nickel fine particles, wherein the fine powder shows X-ray diffraction peaks of nickel and is free of any peak of barium titanate having a perovskite structure in the X-ray diffraction pattern determined by the X-ray diffraction method, but the fine powder shows X-ray diffraction peaks of both nickel and barium titanate having a perovskite structure in the X-ray diffraction pattern after the fine powder is subjected to a heat-treatment at a temperature of not less than 400° C.
Nickel fine powder surface-modified with barium titanate having a perovskite structure, in which the barium titanate having a perovskite structure is adhered to the surface of the individual nickel fine particles and the rate of increase in the weight of the fine powder observed after allowing them to stand in the atmosphere maintained at 400° C. for 2 hours is not more than ½ time that observed for the untreated elemental nickel fine powder.
A method for preparing nickel fine powder surface-modified with barium titanate having a perovskite structure comprising the steps of bringing nickel fine particles into contact with a solution containing a combination of a soluble titanium-containing compound and a soluble barium-containing compound, which can form barium titanate having a perovskite structure through a heat-treatment at a temperature of not less than 400° C. to thus adhere, to the surface of the individual nickel fine particles, a precursor consisting of the reaction product of the soluble titanium-containing compound and the soluble barium-containing compound, then drying the fine particles and heat-treating the fine particles at a temperature of not less than 400° C.
Dependencies are inferred from the claim text.