Silver-coated cobalt powder and preparation method thereof

Abstract

The invention provides a silver-coated cobalt powder and a preparation method thereof. The preparation method of the silver-coated cobalt powder comprises the following steps of: mixing and heating a cobalt salt solution, a dispersing agent and hydrazine hydrate to form a cobalt ion complex solution; the molar ratio of hydrazine hydrate to cobalt salt being (1.3-1. 5):1; keeping the temperature of the cobalt ion complex solution unchanged, adjusting the pH value of the cobalt ion complex solution to be alkaline, and adding the hydrazine hydrate for reaction to generate an elemental cobalt crystal; and adding a soluble Ag salt and the hydrazine hydrate to undergo a reduction reaction, and carrying out solid-liquid separation and drying to obtain the silver-coated cobalt powder. The silver-coated cobalt powder provided by the invention is prepared by a process that hydrazine hydrate is added step by step. The preparation method of the silver-coated cobalt powder has the advantages of simple working procedure, easiness in control, high production efficiency and low production cost, and is suitable for industrial production. The silver-coated cobalt powder prepared by the method has the advantages of small particle size, stable structure, excellent conductivity and strong thermal conductivity.

Description

technical field [0001] The invention belongs to the technical field of cobalt powder metallurgy, and in particular relates to a silver-coated cobalt powder and a preparation method thereof. Background technique [0002] Cobalt powder is widely used in the field of metallurgy and chemical industry, and is an important raw material for the production of metallurgical and chemical products such as battery electrodes, high hardness alloys, diamond tools, and catalyst carriers. [0003] With the advancement of technology, the market's requirements for the quality of cobalt powder have become harsh and diversified, and the demand for functional composite powders is also increasing, and the application of this technology will be further expanded. The process of surface treatment of powder particles by physical or chemical methods to purposely change their physical and chemical characteristics, surface structure and particle morphology is called powder surface modification. This qu...

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Problems solved by technology

Both of these methods have certain disadvantages, the former is due to the generated cobalt hydroxide Co(OH) 2 In the pH range of its reaction system, the solubility is only 10 -6 ~10 -7 order of magnitude, if it is reduced with hydrazine hydrate, the resulting cobalt powder Co will wrap cobalt hydroxide Co(OH) 2 However, pure cobalt powder cannot be obtained; the latter is due to the release of a large amount of heat when adding sodium hydroxide, so that part of the hydrazine hydrate is decomposed in the form of ammonia, resulting in losses and low reduction efficiency

In addition, under alkaline conditions, hydrazine hydrate converts cobalt ions Co 2+ Reduction into cobalt powder Co is thermodynamically feasible, but there are difficulties in kinetics, and it is necessary to add a crystal nucleus initiator to overcome the kinetic energy barrier

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