Overview and Preparation of Tungsten Carbide WC Powder

Tungsten carbide is a compound composed of tungsten and carbon with a molecular formula of WC and a molecular weight of 195.85. It is a black hexagonal crystal with metallic luster, and its hardness is similar to that of diamond. It is a good conductor of electricity and heat. Tungsten carbide is insoluble in water, hydrochloric acid and sulfuric acid, and is easily soluble in the mixed acid of nitric acid and hydrofluoric acid. Pure tungsten carbide is brittle, and if it is mixed with a small amount of titanium, cobalt and other metals, the brittleness can be reduced. Tungsten carbide used as a steel cutting tool is often added with titanium carbide, tantalum carbide or their mixture to improve the anti-knock ability. Tungsten carbide is chemically stable. Tungsten carbide powder is used in cemented carbide production materials.

Tungsten carbide production method

Using metal tungsten and carbon as raw materials, dry-mix tungsten powder with an average particle size of 3-5 μm and carbon black in the same amount with a ball mill. Or heated to 1400-1700℃ in an induction furnace, preferably controlled at 1550-1650℃. In the hydrogen flow, W2C is initially formed and continues to react at high temperature to form WC. Alternatively, tungsten powder can be obtained by thermally decomposing tungsten hexacarbonyl at 650-1000°C in a CO atmosphere, and then reacting with carbon monoxide at 1150°C to obtain WC. The temperature is higher than this temperature to generate W2C.

The tungsten powder (average particle size 3～5μm) is prepared by hydrogenation reduction of tungsten trioxide WO3. Then, the mixture of tungsten powder and carbon black in an equal molar ratio (dry mixing with a ball mill for about 10 hours) is pressed and formed under a pressure of about 1t/cm2. Put the press-molded block into a graphite plate or crucible, and heat it to 1400-1700°C (preferably 1550-1650°C) in a hydrogen flow (using pure hydrogen with a dew point of -35°C) with a graphite resistance furnace or an induction furnace. ℃), and carburizing it will generate WC. The reaction starts from around the tungsten particles, because W2C is formed in the early stage of the reaction, and because the reaction is not complete (mainly because the reaction temperature is low), there are still unreacted and intermediate products W2C in addition to WC. Therefore, it must be heated to the above-mentioned high temperature. The maximum temperature should be determined according to the particle size of the raw tungsten. If the average particle size is coarse particles of about 150 μm, the reaction is carried out at a high temperature of 1550 to 1650°C.

The requirements of cemented carbide on the particle size of tungsten carbide WC, according to the cemented carbide for different purposes, use different particle sizes of tungsten carbide; cemented carbide cutting tools, such as cutting edge V-CUT knife, etc., the finishing alloy is made of ultra-fine Fine-grained tungsten carbide; medium-grained tungsten carbide for rough machining alloys; medium-coarse-grained tungsten carbide for gravity cutting and heavy-duty cutting alloys; coarse-grained tungsten carbide for mining tools with high rock hardness and high impact load; small impact load for rock impact Small, medium-grain tungsten carbide is used as raw material for wear-resistant parts; when stressing its wear resistance, pressure resistance and surface finish, ultra-fine sub-fine and medium-grain tungsten carbide is used as raw material; impact-resistant tools use medium-coarse-grained tungsten carbide as raw material. host.

The theoretical carbon content of tungsten carbide is 6.128% (atomic 50%). When the carbon content of tungsten carbide is greater than the theoretical carbon content, free carbon (WC+C) appears in the tungsten carbide, and the presence of free carbon makes the surrounding carbonization during sintering. Tungsten grains grow, resulting in uneven grains of cemented carbide; tungsten carbide generally requires high compound carbon (≥6.07%) free carbon (≤0.05%), and the total carbon depends on the production process and application range of cemented carbide.

Under normal circumstances, the total carbon of tungsten carbide used for vacuum sintering in paraffin wax process is mainly determined by the compound oxygen content in the compact before sintering. One part of oxygen should be increased by 0.75 parts of carbon, that is, WC total carbon = 6.13% + oxygen content % × 0.75 (assuming sintering The furnace is a neutral atmosphere. In fact, most vacuum furnaces are carburizing atmospheres. The total carbon of tungsten carbide is less than the calculated value).

The total carbon content of tungsten carbide in China is roughly divided into three types of paraffin process. The total carbon content of tungsten carbide for vacuum sintering is about 6.18±0.03% (free carbon will increase) The total carbon content of tungsten carbide for hydrogen sintering in paraffin process is 6.13±0.03% % Rubber process hydrogen sintering tungsten carbide total carbon = 5.90 ± 0.03% The above processes are sometimes crossed, so the determination of tungsten carbide total carbon should be based on specific circumstances.

Minor adjustments can be made to the WC total carbon used in alloys with different application ranges, different cobalt content, and different grain sizes. Low-cobalt alloys can choose tungsten carbide with high total carbon, and high-cobalt alloys can choose tungsten carbide with low total carbon. In short, the specific use requirements of cemented carbide have different requirements for the grain size of tungsten carbide.

Overview of tungsten carbide WC powder

Tungsten carbide is a compound composed of tungsten and carbon with a molecular formula of WC and a molecular weight of 195.85. In its most basic form, tungsten carbide is a fine gray powder, but it can be pressed into shape by a process called sintering and is used in industrial machinery, cutting tools, abrasives, armor-piercing rounds and jewelry.

Tungsten carbide is about twice as stiff as steel and has a Young's modulus of about 530-700 GPa (77,000 to 102,000 ksi), which is twice the density of steel and almost between lead and gold. Its hardness is comparable to corundum (α-Al2O3), and only cubic boron nitride and diamond powder, grinding wheels and compounds with high-hardness abrasives can be used for polishing and finishing.

Tungsten carbide is a black hexagonal crystal with metallic luster and hardness similar to diamond. It is a good conductor of electricity and heat. Tungsten carbide is insoluble in water, hydrochloric acid and sulfuric acid, but soluble in mixed acids of nitric acid and hydrofluoric acid. Pure tungsten carbide is brittle, if a small amount of titanium, cobalt and other metals are added, its brittleness can be reduced. Tungsten carbide used for steel knives is usually added with titanium carbide, tantalum carbide or a mixture thereof to improve knock resistance. Tungsten carbide is chemically stable. Tungsten carbide powder is used as a material for the production of cemented carbide.

Application of tungsten carbide WC powder

Cemented carbide is widely used as high-speed cutting tools, furnace structural materials, jet engine parts, cermet materials, resistance heating elements, etc., for the manufacture of cutting tools, wear-resistant parts and melting crucibles for metals such as copper, cobalt, and cobalt. Bismuth, wear-resistant semiconductor film.

Tungsten carbide is used as superhard tool material and wear-resistant material.

Tungsten carbide can form solid solutions with many carbides. WC-TiC-Co carbide tools have been widely used.

Tungsten carbide can also be used as a modification additive for NbC-C and TaC-C ternary carbides, which can reduce the sintering temperature and maintain excellent performance. Can be used as aerospace material.

Tungsten carbide (WC) powder can also be synthesized using tungstic anhydride (WO 3 ) and graphite in a reducing atmosphere at a high temperature of 1400~1600°C. Dense ceramic products can be obtained by hot pressing sintering or hot isostatic pressing.

Tungsten carbide (WC) powder can also be used to produce high-performance nanocrystalline or ultra-fine keratin alloys, hard surface wear-resistant spraying and petrochemical cracking catalysts; chipless forming tools; cutting tools; mining fees; nanocomposites (for improving hardness, strength and wear resistance); corrosion-resistant coatings; wear-resistant coatings; corrosion-resistant coatings; wear-resistant parts.

Tungsten carbide WC powder price

The price of tungsten carbide WC powder will change randomly with the production cost, transportation cost, international situation, exchange rate and market supply and demand of tungsten carbide WC powder. Tanki New Materials Co., Ltd. aims to help industries and chemical wholesalers find high-quality, low-cost nanomaterials and chemicals by providing a full range of customized services. If you are looking for tungsten carbide WC powder, please feel free to send an inquiry to get the latest tungsten carbide WC powder price.

Tungsten carbide WC powder suppliers

As a global supplier of tungsten carbide WC powder, Tanki New Materials Co., Ltd. has extensive experience in the performance, application and cost-effective manufacturing of advanced technology and engineering materials. The company has successfully developed a series of powder materials (including oxides, carbides, nitrides, single metals, etc.), high-purity targets, functional ceramics and structural devices, and provides OEM services.