Preparation method for cobalt nanoparticles

Abstract

The invention discloses a preparation method for cobalt nanoparticles. According to the preparation method, cobalt nitrate is used as a raw material, low molecular alkylol amine is used as a reducing agent, vinyl pyrrolidone is used as a surfactant and a stabilizer, and absolute ethyl alcohol, absolute methyl alcohol or absolute propyl alcohol is used as a solvent; and the preparation method comprises the following steps of: dissolving the materials respectively and mixing uniformly; reacting with stirring under the temperature condition of 60-80 DEG C until the color of reaction solution becomes stable dark yellow; naturally cooling to room temperature; and concentrating and drying to obtain spherical cobalt nanoparticles. The method provided by the invention has the advantages of low toxicity in production, low production temperature, simple production process, simple equipment and low production cost; and the obtained cobalt nanoparticles are spherical and have high dispersibility and average particle diameter of not greater than 10 nm.

Description

technical field [0001] The invention relates to the preparation of metal nanoparticles, in particular to a method for preparing cobalt nanoparticles. Background technique [0002] Cobalt nanoparticles are a nano-functional metal material with a series of unique physical and chemical properties. They have broad application prospects in many fields such as catalysts, battery materials, cemented carbide binders, and new optical sensor materials. As a binder in powder metallurgy, cobalt powder can ensure that the cemented carbide has a certain toughness. The micro-drill prepared by sintering nano-WC-Co powder is 3 to 4 times longer than the life of ordinary cemented carbide drills when processing printed circuit boards. times, 50 times that of stainless steel drills, the best cutting speed increased by 0.98 to 2.74 times, and the damage resistance was significantly improved. The composite catalyst made of nano-cobalt can increase the efficiency of organic hydrogenation or dehyd...

AI Technical Summary

Problems solved by technology

At present, cobalt powder is mainly produced by oxalate precipitation-calcination-hydrogen reduction method in my country. The particle size of the cobalt powder obtained by this method is generally 1.0-3.0 um, the shape is dendritic and the particle size distribution is uneven, and it is easy to be accompanied by coarse phenomenon. , my country is still unable to industrially produce ultra-fine spherical cobalt powder with an average particle size below 0.5um

As the world's largest cobalt producer, OMG of the United States and UM of Belgium mainly adopt three nano-cobalt powder preparation processes: thermal decomposition method, oxide reduction method and high-pressure hydrogen reduction method. These three methods have strict requirements on equipment , the size is not easy to control

The chemical solution method can greatly reduce the production cost because the required equipment is simple, the raw materials are cheap, and the reaction condition requirements are low. For example, the invention patent of CN1923415 discloses the use of hydrazine hydrate as a reducing agent, cetyltrimethyl Ammonium bromide is a dispersion stabilizer, which reacts with cobalt salt aqueous solution at 90-200°C and greater than 1 atmospheric pressure to obtain flaky cobalt nanoparticles. The average particle size of cobalt nanoparticles obtained by this method is relatively large, generally Tens of nanometers, the reducing agent hydrazine hydrate is highly toxic and affects health

Wang Zhiyuan of Beijing University of Science and Technology reported that CoCl 2 . 6H 2 O as raw material, with NaBH 4 As a reducing agent, triethanolamine and PVP are used as complexing agents to synthesize cobalt nanoparticles in absolute ethanol. The average particle size of cobalt nanoparticles obtained by this method is also greater than 10nm, and it is easy to produce cobalt borides. NaBH 4 The toxicity is also greater, the production cost is higher, and the preparation process is also more complicated