2023-11-02

Optical and mechanical properties of graphene

Graphene has excellent optical properties, with an absorption rate of about 2.3% over a wide wavelength range, making it almost transparent. Within the thickness range of several layers of graphene, with each increase in thickness, the absorption rate increases by 2.3%. Large area graphene films also have excellent optical properties, and their optical properties change with the thickness of graphene. This is an unusual low energy electronic structure possessed by single-layer graphene. At room temperature, a voltage is applied to a double-gate double-layer graphene field-effect transistor, and the bandgap of graphene can be adjusted between 0 and 0.25 eV. When a magnetic field is applied, the optical response of graphene nanoribbons can be tuned to the terahertz range.When the intensity of the incident light exceeds a certain critical value, graphene's absorption reaches saturation. These characteristics allow graphene to be used as a passive mode-locked laser. This unique absorption

2023-11-07

The difference between expanded graphite and ordinary graphene

Expanded graphite, also known as flexible graphite or vermicular graphite, is a new type of carbon material. Expanded graphite has many advantages, such as large specific surface area, high surface activity, good chemical stability, and high temperature resistance. The commonly used preparation process for expanded graphite is to use natural flake graphite as the material, which is first oxidized to form expandable graphite, and then expanded to form expanded graphite. Expanded graphite materials can instantly expand by 150-300 times in volume when exposed to high temperatures, changing from flaky to wormlike, resulting in a loose structure, porous and curved structure, expanded surface area, improved surface energy, and enhanced adsorption of flake graphite. Wormlike graphite can be self embedded between them, making the material have functions such as flame retardancy, sealing, and adsorption. It has wide applications in fields such as life, military, environmental protection, and c

2023-05-19

Granular graphite

1. Refractory material: use graphite, smelting colors, special steel and other valuable metals such as graphite, smelting colors, special steel, etc. in the metallurgical industry, as a magnesium carbon brick in the steel refining furnace; in addition, it is also used as a steel insulation, protective residue and steel bag covering agent.2. Conductive material: Graphite can be used as electrodes, brushes, electrical rods, carbon pipes, and visual tube coatings on the electrical industry.3. Abrasion -resistant materials and lubricants: It can be used for wear -resistant and lubricating materials in the mechanical industry. For example, graphite can slide at a speed of 100m/s at a temperature range of -200-2000 ° C, without lubricating oil. Graphite lubricants include oil agents, water, powder colloidal graphite, graphite lubricating fat, graphite root roots, etc.4. Sealing materials: Use flexible or expanded graphite as lyric axes, water turbines, gas turbines, and piston ring cushions

2023-02-20

Graphite board antioxidant solution increases the period of use

Graphite boards are used in many industries, and due to their different advantages, future use will be more common. Old iron is very concerned about the use of graphite boards. The solution of the antioxidant solution of graphite board can reasonably increase the use period.After the formation of graphite board, it must be solved by antioxidantization. Generally, antioxidants are used, which is a thick liquid state. The ingredients are heat -resistant nano -ceramic particles. In the natural environment of air oxidation within 1300 ° C in the application temperature of the graphite board, its antioxidant actual effect is very good. After a variety of specifications of graphite boards with pre -immersed in the antioxidant protective film, its liquid can penetrate into the pores of the graphite board, and produce a layer of 0.02mm antioxidant on the surface of the air holes and graphite molds. The sexual protective membrane is exactly the reasonable blocking gas of this layer of protecti

2023-03-22

Several factors of hot pressure graphite mold damage

1. Broken: Graphite mold directly contacts the matrix powder containing diamond. The contact surface is in a high pressure state. The hardness of diamond and graphite mold is too poor. The surface of the mold that is in contact with diamond tool head will produce concave pits.Second, the type of damage: During the sintering process, the matrix powder infiltrates into the oxidation gap of the graphite mold under the melting state, resulting in the adhesion between the tool head and the mold, making it difficult for molding. The repeated attack of the mold can remove the mold, which causes the lack of edges and metal pit in the mold.Third, the wear size of graphite molds is very poor: some substrate powder will be squeezed out of the mold surface in the melting state to attach to the graphite material. Before using the mold next time, metal residues must be removed manually, which causes the shape and size of the mold to exceed the tolerance.Fourth, surface oxidation and cracking: Becau

2023-02-10

Graphite development direction

Mainly deep processing, realize some important engineering projects, build a complete industrial chain, and guide the healthy and scientific development of the graphite industry. The first is the transformation of old technical equipment; the second is the current hot technical products of the development of charcoal graphite materials, such as the negative materials of lithium -ion batteries, the industrialization and intensiveization of the same -sex graphite, hig

2023-04-19

Common ways to expand graphite

1. Chemical intervening method: The prepared initial raw materials are high -carbon scales -shaped graphite. The remaining chemical reagents such as concentrated sulfuric acid (more than 98 %), hydrogen peroxide (more than 28 %), potassium permanganate, and other industrial -grade reagents are used The general steps for preparation are: Different proportion of hydrogen dioxide solutions, natural scales, and concentrated sulfuric acids with different proportion at the appropriate temperature with different adding procedures, react for a certain period of time under continuous stirring, and then wash it to neutrality and centrifugal separation. After dehydration, it is dry at 60 ° C vacuum.2. Electrochemical Law: Treatment of graphite powder in a strong acidic fluid to make expansion graphite, hydrolysis, cleaning and dryness. It mainly uses sulfuric acid or nitric acid as strong acid. Essence3. Ultrasonic oxidation method: During the process of preparation of swelling graphite, the ult

2023-02-08

Graphite flotation method

Floating is a commonly used and important mineral method. Graphite has good natural floating. Basically, all graphite can be purified by floating methods. In order to protect graphite scales, most of the graphite flotation uses multiple sections of processes. Graphite flotation collecting agents are generally used for kerosene, with a dosage of 100 to 200g/t. The foaming agent is generally used with pine or butad ether, and the amount is 50 to 250g/t.

Types of battery materials and its application areas

Lithium ion batteries are one of the currently widely used batteries in the market. The types of materials mainly include lithium cobaltate, lithium iron phosphate, lithium nickel cobalthocco, and lithium titanic acid. The advantage of lithium -ion batteries is that high energy density, high energy storage efficiency, long life, etc. The commonly used materials for nickel -metal hydride batteries are hydrogen anode and nickel oxide cathode. The advantage is that the use of safety, no pollution to the environment, and long life.A fuel cell is a battery that directly converts chemical reactions into electrical energy. The types of materials mainly include potassium hydroxide, sodium hydroxide, and sodium boric acid. Fuel cells have the advantages of low pollution, but their application scope is currently relatively limited. The types of sodium ion battery materials include sodium sulfide and sodium phosphate. The advantage of sodium ion batteries is that it is relatively cheap and long

2023-08-14

Which raw materials are selected for the production of traditional carbon materials

Various metallurgical furnace carbon blocks (such as blast furnace carbon blocks, ferroalloy furnace carbon blocks, calcium carbide furnace carbon blocks, and aluminum electrolysis cell cathode carbon blocks, etc.) are used at a certain high temperature. Therefore, carbon blocks should have high mechanical strength, thermal stability, and corrosion resistance, but the ash content requirements are not too strict. Except for the bottom carbon blocks used in aluminum electrolysis cells, it is not necessary to measure conductivity. The production of carbon blocks mostly uses anthracite as the aggregate and metallurgical coke as the filling material. To improve the thermal conductivity and corrosion resistance of carbon blocks, a certain amount of graphite fragments (or natural graphite) can be added. In order to improve the thermal conductivity and conductivity of carbon blocks, semi graphite carbon blocks can be produced by electrocalcining anthracite.The raw materials used for conductiv