2022-11-23
2023-11-16There are two classification methods for graphene. One is based on the number of layers, which can be divided into four categories: single-layer, double-layer, few layer, and multi-layer products; Another type of product can be divided into three categories according to its form: powder, slurry, and film. Graphene powder and graphene thin film are currently the two main forms of graphene materials. The former is mostly doped in other materials and is widely used in coatings and lithium-ion batteries; Graphene thin films are widely used in the fields of electronics, photons, and optoelectronic devices due to their advantages of transparency, conductivity, and flexibility. Different graphene products have certain differences in raw materials due to different preparation methods. Graphene powder is mainly formed by physical or chemical methods, and the main raw material is natural graphite. Graphene thin films are mainly deposited by chemical vapor deposition, and their raw materials are
2023-11-161. Varieties of graphite electrodesElectric arc steelmaking furnaces are generally divided into three categories, namely ordinary power electric furnaces, high-power electric furnaces, and ultra-high power electric furnaces. Corresponding to the power level of electric furnace steelmaking, graphite electrodes are also divided into three types, namely ordinary power graphite electrodes (code RP level), high-power graphite electrodes (code HP level), and ultra-high power graphite electrodes (code UHP level). The nominal diameter of the electrode ranges from 75mm to 700mm. The physical and chemical properties of high-power and ultra-high-power graphite electrodes are superior to ordinary power graphite electrodes, such as low resistivity, high bulk density, high mechanical strength, low linear expansion coefficient, and excellent antioxidant performance. The physical properties of three types of graphite electrodes are shown in Table 1.Selection of graphite electrodes for AC arc steelmak
2023-11-15Graphite powder has high conductivity. The conductivity of graphite powder is an important factor in the conductive finished product of graphite powder. There are many factors that affect the conductivity of conductive graphite powder, such as the ratio of graphite powder, external pressure, environmental humidity, humidity, and even light. The following methods can usually be used to measure the conductivity of graphite powder:1. Voltammeter method for measuring resistanceSpecific method: Use a precision small range electricity meter or a resistance multimeter to measure and compare the experiment. You can use a small light bulb to measure its conductivity based on its brightness. If the light bulb is brighter, it indicates a smaller resistance.2. Measuring the conductivity of conductive graphite powder through resin methodGo buy some resin for conductive paint, add the same amount of conductive graphite powder, and then apply it on a board to measure its conductivity using a digital
2023-11-15(1) Detonation cracking methodThe detonation cracking method utilizes the properties of graphite that can accommodate foreign negative ion layers to form expandable graphite or lower order GICs, where the ion layer contained is called the insertion layer. In expandable graphite or low order GICs, the insertion layers are regularly arranged in graphite layers. During detonation, the insertion layer rapidly decomposes and releases a large amount of gas, impacting the graphite layers and pushing adjacent graphite layers apart to prepare nano graphite thin sheets. During the detonation process, * * plays two roles simultaneously: firstly, it releases a large amount of heat during the explosion, causing the decomposition of expandable graphite or lower order GICs; The other is to use the shock wave generated during detonation to crush the graphite sheet, achieving the effect of refining the graphite, thereby preparing flake graphite with smaller diameter and very thin thickness.At present,
2023-11-14Do you know what a diamond is? Its chemical composition is carbon (C), and natural diamonds can only be called "diamonds" after being polished by diamonds. Natural diamonds are very rare, with only 2 diamonds weighing over 1000 carats (1 gram=5 carats) in the world and only a few diamonds weighing over 400 carats. The largest diamond discovered in China to date weighs 158.786 carats, which is known as the "Changlin Diamond". Rare things are precious, and precisely because natural diamonds that can be used as "diamonds" are rare, people want to replace them with "artificial" diamond, which naturally reminds them of the "twin" brother of diamonds - graphite.The chemical composition of diamond and graphite is carbon (C), which scientists refer to as "homomorphic variants" or "allotropes". From this term, it can be inferred that they share the same "quality", but their "form" or "nature" are different and vastly different. Diamond is currently the hardest substance, while graphite is one
2023-11-14Graphite is an allotrope of elemental carbon, where each carbon atom is surrounded by three other carbon atoms (arranged in a honeycomb like pattern with multiple hexagons) that are covalently bonded to form covalent molecules. Due to its excellent properties, graphite is used to make many materials. Below are several physical and chemical indicators that need to be understood when selecting graphite materials:1. Average particle diameter of the materialThe average particle diameter of a material directly affects its discharge condition. The smaller the average particle size of the material, the more uniform the discharge of the material, the more stable the discharge condition, and the better the surface quality. For forging and die-casting molds with low surface and precision requirements, it is usually recommended to use materials with coarser particles; For electronic molds with high surface and precision requirements, it is recommended to use an average particle size of 4 μ Mater
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