Ultrafine Tungsten Carbide Powder Preparation Anti-Spontaneous Combustion Process

Ultrafine cemented carbide is a tool material developed in recent years, mainly based on ultra-fine WC powder and adding appropriate binder (such as Co) and grain growth inhibitor to produce high hardness, high wear resistance and high toughness cemented carbide materials. Its performance is higher than that of conventional cemented carbide. It has shown more and more extensive application prospects in difficult-to-process metal material tools, miniature drill bits in the electronics industry, precision molds, and dental drills.

In industrial production, ultrafine tungsten powder and carbon powder precursors are generally used to produce ultrafine tungsten carbide powder by high-temperature carbonization. However, since the method has the advantages of large specific surface area, high surface activity, a slight contact with the air is a phenomenon of oxidation spontaneous combustion, which affects the quality of the products and causes the loss of materials.

In order to reduce the oxidation and spontaneous combustion of the precursor, the prepared ultrafine tungsten carbide powder is not easy to spontaneous combustion and the oxygen content is low. Some scholars have proposed a preparation method of ultrafine tungsten carbide powder, with ultrafine tungsten powder and carbon black as raw materials, which are characterized by the following steps: (1) Passivation of ultrafine tungsten powder: ultrafine tungsten powder filled with pure carbon dioxide gas was allowed to stand for more than 12 hours to passivate the surface of ultrafine tungsten powder to prevent spontaneous combustion of ultrafine tungsten powder; (2) With carbon: the passivated ultrafine tungsten powder and carbon powder loaded with carbon machine, the cooling water cooling, pass into the inert gas mixture after mixing, natural cooling after mixing; (3) Carbonization: the mixed good fine tungsten powder and carbon powder in a carbonization furnace carbonized high-temperature synthesis of massive tungsten carbide powder; (4) Crushing and sieving: the lump WC powder is crushed into the pulverizer, and then added under the protection of inert gas to protect the ultrafine powder. After cooling, the tungsten carbide powder is sieved.

The ultrafine tungsten carbide powder produced by this method is not easy to spontaneous combustion, and the traditional preparation method of ultrafine tungsten carbide powder product comparison of oxygen content decreased by 20 ~ 40%, increasing the mixing equipment of ultrafine tungsten powder and carbon powder with the weight of carbon in the process, the mixing quantity of ultrafine tungsten powder and carbon powder is 1~2 times higher than the traditional method, the production efficiency is improved.

• < Prev
• Next >