Blog | VICHEM - Part 12

23 9月

Preparation of nanometer tungsten carbide composite powder

Tungsten carbide is a black gray crystalline powder. Relative density 15.6(18/4℃), melting point 2600℃, boiling point 6000℃, Mohs hardness 9. Tungsten carbide insoluble in water, hydrochloric acid or sulfuric acid, soluble in nitric acid and hydrofluoric acid mixture. Tungsten carbide reacts strongly with fluorine at room temperature and is oxidized to tungsten oxide when heated in air. At 1550 ~ 1650℃, the metal tungsten powder can be directly combined with carbon black, or at 1150℃, the tungsten powder can [...]

The process control of the crystallization of ammonium dimolybdate and the process conditions for the formation of single crystal

Ammonium molybdate is a typical homopolybdate with many types, mainly including ammonium dimolybdate, ammonium tetramolybdate, ammonium heptamolybdate, ammonium ocmolybdate, ammonium dodecolybdate and ammonium tetramolybdate. Ammonium molybdate used in the industry is mostly the mixture of the above ammonium molybdate in different proportions, which is easy to be hygroscopic and agglomerated, and not easy to disperse. Ammonium molybdate is the main raw material for preparation of molybdenum-based products, especially molybdenum powder. Its phase purity and chemical and physical properties have [...]

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09 8月

Titanium suboxide Conductive ceramic electrode material (Ti4O7)

The titanium suboxide ceramic electrode material is produced by reducing high-purity titanium dioxide powder by hydrogen H2 at a high temperature of 1200 degrees. The main crystal phase is Ti4O7. The appearance of the product is blue-black flow dynamic powder. High conductivity of metal-like materials. Excellent chemical stability against acids and alkalis. Unique electrochemical performance. With high mechanical strength, it can be easily formed into electrode shapes such as plates, tubes, and rods. The outstanding physical property of titanium suboxide is that it has good electrical [...]

The resonance level improves the thermoelectric properties of germanium telluride

Recently, the team of Professor Zhang Wenqing, Institute of Materials Genome Engineering, Shanghai University, and Professor Jihui Yang, Department of Materials Science and Engineering, University of Washington (click to view the introduction) cooperated with the research team of GeTe thermoelectric materials, following the basic ideas of materials genome science, integrated material calculation, material preparation and material characterization. The first principle method is used to calculate the electron energy band and electron energy state density of GeTe high and low [...]

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09 7月

Preparation of tungsten chloride

This procedure is exactly the same as the preparation of tungsten tetrachloride, but the product cannot contact with air due to its strong hygroscopicity, so it should be fully dried and preserved. Under this reaction condition, there is no protective atmosphere, so it is difficult to ensure that tungsten pentachloride is not decomposed. During refining, the product is put into a hard glass tube and placed in the air of vacuum or nitrogen and carbon dioxide. The glass tube [...]

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01 7月

Preparation and application of titanium nitride

The chemical properties of nitrogen element are very stable, but under some special conditions, it can form nitrides with many elements. Among these nitrides, the transition metal nitrides — Titanium nitride (TiN) has become the focus of research at home and abroad. Titanium nitride is a small wet structural material with attractive gold color, high melting point, high hardness, good chemical stability, and metal, and has high conductivity and superconductivity. It can be used in high temperature structural materials [...]

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12 6月

Preparation and application of molybdenum silicate

Molybdenum Disilicide, MoSi2 is a kind of silicon Molybdenum compound, also known as Molybdenum Disilicide, Molybdenum silicide has high melting point, low density, good thermal conductivity and good electrical conductivity and excellent high temperature oxidation resistance, high elastic modulus, low thermal expansion coefficient, high strength, good resistance to chemical corrosion and thermal shock resistance, are widely used in high temperature heating element component materials and high temperature oxidation resistance coating materials, is also the most development potential of high [...]

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05 6月

Vanadium dioxide — a revolutionary material for the future electronics industry

Because of its unique properties, vanadium dioxide has become an ideal choice to replace silicon for a new generation of low-power electronic devices. Swiss researchers recently demonstrated the application of vanadium dioxide to aerospace communications (600677) systems to achieve programmable rf electronics, highlighting the oxide’s potential. Vanadium dioxide has phase transition characteristics and forms that can be converted between an insulator and a metal, acting as an insulator at room temperature and as a metal conductor above 68 degrees Celsius. [...]

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29 5月

Comparison of ni-cr and tantalum nitride film resistors in communication applications

Prior to the widespread acceptance of surface mounted sheet resistors in the 1980s and 1990s, metallized hole mounted molded resistance was usually used in precision applications. Through hole mounted discrete resistors have always been made by depositing thin film resistive materials on cylindrical ceramics. The leads are connected to both ends of the ceramic and the columnar resistance devices are molded or coated to produce a fully sealed product as shown in figure 1. The sheet resistance shown in [...]

Main applications of tantalum silicide

Metal silicides are similar to metals in electrical conductivity, high temperature performance, oxidation resistance and compatibility with the production process of silicon integrated circuits. Transition metal silicides can be used for low-resistance gate and interwire, schottky gate and resistance contact. Tantalum silicide preparation method includes: the combustion synthesis (combustionsynthesis, CS) or self-propagating high-temperature synthesis, arc melting method, etc. Combustion synthesis or self-propagating high temperature synthesis is a method for the synthesis of intermetallic compounds by the exothermic reaction of [...]

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