Preparation And Exterior Improvement Of Ultrafine Cobalt Powder By Polyols Reduction

It had been briefly summarized about the conception and microcosmic characters and preparing methods of ultrafine powder , at the same time , it had been summarized the developmental survey and actuality, fundamental characters, applications and preparing methods of ultrafine cobalt powder in the paper, and the process technology of ultrafine cobalt powder was thought to be one of important steps in the preparation and application of high property materials, limitations existed in the current preparing methods of ultrafine cobalt powder had also been pointed out, and new technicses were bring forward aiming at the other methods' problems and the resource of cobalt existed in the preparing methods of cobalt powder. From different comparison of preparation process , it can be drew , on the one hand , that ultrafine cobalt powder is more pure , more thin , more symmetrical and spherical than other preparation process by polyols reduction , on other hand , there is more raw materials to be used , more simple preparation technics , cobalt size and shape can be controlled than other preparation process by polyols reduction .If it is used for industrial production ,there will be researched and explored in technology parameters and condition of granularity controlling.With the method of solution chemistry, it had been explained about the influence of hydrolyzing conditions to the granularity of cobalt hydroxide. Using the theory of redox and crystal development, the influence of the adding quantity and the adding time of reagent to the capability of cobalt powder, and it referably explained the relationships between the ratios of different raw materials and the size and shape of ultrafine cobalt powder.Taking, cobalt nitrate , cobalt carbonate , cobalt sulfate , three kinds of cobalt salts respectively as the raw material , cobalt hydroxide was prepared in this paper . The spherical , monodispersed , ultrafine cobalt powder with a face centered cubic structure and a size less than lum were synthesized by the reduction of tetra hydrated in glycol or 1,2-propanediol. These were studied that the prophase cobalt hydroxide prepared by different cobalt salts affecting following reaction and the quantity of sodium hydroxide and cobalt hydroxide in unit volume of glycol or 1,2-propanediol , reaction time , temperature andadditives affecting particle size and shape . As a result showing , the cobalt powder by glycol reducing was spherical , the crystal mostly with face centered cubic (fcc) structure , 0.8um of average particle size , the cobalt content >99.5% through analysis with the scanning electron microscope and the X-ray diffraction . Through comparison of effects of ethylene glycol and propylene glycol on the time of complete reaction might be shortened greatly with propylene glycol as the reduction agent . Different reaction mechanisms might result in the different purity and particle size of cobalt powder .