Tungsten Carbide (Tungsten Carbide) is a compound composed of tungsten and carbon. The molecular formula is WC and the molecular weight is 195.85.
It 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, and easily soluble in the mixed acid of nitric acid and hydrofluoric acid. Pure tungsten carbide is fragile. If a small amount of titanium, cobalt and other metals are added, brittleness can be reduced. Tungsten carbide used as a steel cutting tool is often added with titanium carbide, tantalum carbide, or a mixture thereof to improve the anti-knock ability. The chemical properties of tungsten carbide are stable. Tungsten carbide powder is used in cemented carbide production materials.
The tungsten-carbon binary system can form two types of carbides, namely WC and W2C. Among them, WC is the primary raw material for manufacturing cemented carbide, and it is also an essential raw material powder for preparing high wear-resistant coatings in the field of thermal spraying. WC has high hardness, unusually high-temperature hardness. Co can thoroughly wet WC, Ni, Fe and other metal melt, especially the wettability of cobalt melt to WC*. When the temperature is raised above the melting point of the metal, WC can be dissolved in these metal melts, and when the heat is lowered, WC can be precipitated. These excellent properties make it possible to use cobalt or nickel as the binder phase material, and sinter or coat at high temperature to form a wear-resistant coating with excellent wear resistance.
The main disadvantage of WC is its weak resistance to high-temperature oxidation. It is severely oxidized in the air at 500 to 800 degrees Celsius, and it can be quickly resolved as W2C and carbon in an oxidizing atmosphere by intense heat, so-called "carbon loss". This can be achieved by pre-protecting the WC particles by using a heat-resistant and oxidation-resistant metal as the coating layer or bonding phase; it can also be solid-dissolved with TaC, TIC, etc. to form composite carbides to improve the heat-resistant and oxidation-resistant properties of WC. WC is still stable when heated to 2850 degrees Celsius in an Ar atmosphere, and is not affected by high-temperature nitrogen.
W2C has a higher melting point and hardness than WC. It can form a W2C+WC eutectic mixture with WC. The melting point is reduced, and it is easy to cast. It is the so-called "cast tungsten carbide" or "fusible tungsten carbide". 3.8%~20% (mass), including 78%~80% (mass) of W2C and 20%~22% (mass) of WC. This cast tungsten carbide is a low-cost *hard* wear-resistant material.
WC powder can also be mixed with cobalt-based, nickel-based and iron-based self-fusible alloy powders, nickel-aluminium self-adhesive composite powders, and is widely used to prepare high wear-resistant coatings, especially wear-resistant particle wear, hard surface wear and mud sand Erosion wear and other fields. Tungsten carbide powder is mainly used as a raw material powder for thermal spraying wear-resistant coating. Vacuum plasma spraying, protective atmosphere plasma spraying wear-resistant surface can be used, but the adhesion of the sheet is not excellent.
It is reported that scientists have made new progress in the green p-xylene (PX) synthesis route and designed a bio-fermentation product (bio-based isoprene) and glycerin dehydration product (acrolein) of lignocellulose resources as raw materials, using carbonization Tungsten-catalyzed synthesis route of intramolecular hydrogen transfer tandem reaction. This reaction can achieve a total PX yield of up to 90%
Aromatic hydrocarbons are essential petrochemical products. As the most critical aromatic hydrocarbon, PX is the first-class primary chemical raw material for the production of three significant synthetic materials-synthetic resin, synthetic fibre and synthetic rubber. To alleviate the insufficient supply of PX in the country, the research team is committed to the development and utilization of renewable biomass resources, choosing to transform and prepare PX and other aromatic hydrocarbon products and formed a highly selective synthetic route from biomass to toluene.
The researchers chose isoprene and acrolein as the substrates of the biomass platform with a specific structure. First, under the catalytic action of Lewis acid ionic liquid, through the Diels-Alder reaction, a six-membered para-substituent was constructed. Ring intermediate-4-methyl-3-cyclohexene formaldehyde. Subsequently, under the effect of tungsten carbide catalyst, this intermediate produced PX through continuous gas-phase dehydrogenation-hydrodeoxygenation reaction. The total yield of PX in the two-step reaction was as high as 90%. Besides, by changing the substrate molecular substituents and functional groups, other bio-based aromatic hydrocarbons can be expanded and prepared, with a single product yield of 80% to 92%.
The research team used tungsten carbide powder as a catalyst to achieve a highly coupled reaction of dehydroaromatization and hydrodeoxygenation through intramolecular hydrogen transfer. The tungsten carbide surface shear reaction mechanism in this process is entirely different from the traditional precious metal catalysis process, and carbon atoms can be retained in the product by 100%. The main by-product is water, which facilitates the separation of the PX product. The research results provide a new idea for exploring the preparation of aromatic chemicals from biomass resources.
Besides, The first thing that comes to mind when it comes to tungsten is the filament. Tungsten is a rare high-melting metal, and its melting point is the highest among all unalloyed metals. At the same time, tungsten has an extreme electrical conductivity. Therefore, tungsten was used by the great inventor Edison for the production of filament. Tungsten is widely used in modern technology in pure metal state and alloy system state. It is called "industrial tooth" and "industrial salt" and is an essential strategic metal. However, according to current consumption, tungsten ore is only sufficient for about 140 years. The recycling of tungsten can make up for the shortage of tungsten ore storage.
Recycling tungsten has excellent economic and environmental benefits. The recovered tungsten carbide/tungsten waste scrap has a higher tungsten content than tungsten ore, especially sintered tungsten carbide, where the tungsten content is often more top than 90%. The extraction of tungsten through tungsten carbide and other tungsten wastes not only saves the addition of auxiliary materials such as hydrochloric acid but also reduces the generation of wastewater compared to the extraction of tungsten ore, thereby reducing the production costs of enterprises and the investment in wastewater treatment, avoiding Environmental pollution.
TRUNNANO (Luoyang Trunnano Tech Co., Ltd ) is a professional Tungsten Carbide manufacturer with over 12 years experience in chemical products research and development. If you are looking for high quality Tungsten Carbide, please feel free to contact us and send an inquiry.
