Method for preparing cobalt-coated tungsten carbide powder by freezing

Abstract

The invention belongs to the field of hard alloy and material metallurgy, and particularly discloses a method for preparing cobalt-coated tungsten carbide powder by freezing. According to the method,metal cobalt salt and tungsten carbide powder are used as raw materials, and the preparation of the uniform cobalt-coated tungsten carbide powder is realized through the steps of dissolution, freezingcrystallization, three-step heat treatment and the like. The method comprises the following steps that the cobalt salt is dissolved in a hot liquid to obtain a cobalt-containing precursor solution, the tungsten carbide powder is added as a nucleating agent and gradually cooled in the stirring process, the cobalt salt is separated out and adhered and wraps outside the tungsten carbide powder to obtain uniformly-wrapped tungsten carbide, and the cobalt salt composite powder is dried, decomposed and reduced to obtain the uniformly-mixed cobalt-coated tungsten carbide powder at three different temperatures. The method realizes uniform tungsten carbide. The preparation method of the cobalt-coated powder has the advantages that the process flow is simple, the Co content of different brands canbe obtained, the granularity is easy to control, and the problem that a cobalt pool and the like in the current hard alloy production process are not uniform is effectively solved.

Description

technical field [0001] The invention belongs to the field of cemented carbide and material metallurgy, and more specifically relates to a method for freezing and preparing cobalt-coated tungsten carbide powder. Background technique [0002] WC / Co cemented carbide materials are widely used in mechanical processing, electronic textiles, national defense and military industry, geology and metallurgy and other fields. At present, the production method of WC / Co cemented carbide is to mix tungsten carbide and cobalt powder by solid ball milling to obtain tungsten carbide-cobalt mixture, which is formed by pressing and sintering. In this method, it is difficult to mix tungsten carbide and cobalt evenly, which affects the performance of cemented carbide products, and makes controlling the formation of cobalt pools a common problem in production. With the development of ultra-fine and low-cobalt cemented carbide, the requirements for mixing tungsten carbide and cobalt are higher. T...

AI Technical Summary

Problems solved by technology

The traditional production method of tungsten carbide-cobalt composite powder has been difficult to meet the demand, and a number of solid-liquid and liquid-liquid production methods of tungsten carbide-cobalt composite powder have been studied

[0003] In terms of solid-liquid mixing, Chinese patent CN103056376A and Chinese CN102198514A use waste cemented carbide as raw material, mix it with water-soluble carburizing and spheroidizing agent after oxidation and crushing, and prepare a mixed aqueous solution, which is subjected to rapid spray drying, reduction synthesis and carbon adjustment , to obtain tungsten carbide cobalt composite powder, this method has a long process, is easy to introduce impurities, and has a single processing object

Chinese patent CN102198514A uses cobalt salt methanol solution and tungsten carbide powder to mix to obtain planar cement, and then reduces to obtain tungsten carbide-cobalt composite powder. The organic system limits the preparation of composite powder with high cobalt content.

[0006] In summary, the current solid-solid production process has the problem of cobalt segregation and cobalt pools, and there is no simple and versatile WC-Co uniform powder production for solid-liquid and liquid-liquid to solve the problem of high-performance cemented carbide production. raw material problem

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