What are the properties of EDM graphite materials?

Special properties of EDM graphite materials:
Graphite has the following special properties due to its special structure:
1) High temperature resistance: the melting point of graphite is 3850 ± 50 ℃, and the boiling point is 4250 ℃. Even if it is burned by ultra-high temperature arc, the weight loss is very small, and the coefficient of thermal expansion is also very small. The strength of graphite increases with the increase of temperature. At 2000 ℃, the strength of graphite is doubled. 　　
2) Conductivity and thermal conductivity: the conductivity of graphite is 100 times higher than that of general non-metallic minerals. Its thermal conductivity exceeds that of metal materials such as steel, iron and lead. The thermal conductivity decreases with the increase of temperature, and even at extremely high temperatures, graphite becomes an insulator. Graphite can conduct electricity because each carbon atom in graphite forms only three covalent bonds with other carbon atoms, and each carbon atom still retains one free electron to transfer charges. 　　
3) Lubricity: the lubricity of graphite depends on the size of graphite scales. The larger the scales, the smaller the friction coefficient, and the better the lubricity. 　　
4) Chemical stability: graphite has good chemical stability at normal temperature, and can resist acid, alkali and organic solvent corrosion. EDM graphite material
5) Plasticity: graphite has good toughness and can be rolled into very thin flakes. 　　
6) Thermal shock resistance: when graphite is used at normal temperature, it can withstand drastic changes in temperature without damage. When the temperature changes abruptly, the volume of graphite changes little and cracks will not occur. 　　
Source of the name: it comes from the Greek "graphein", which means "for writing". By German chemist and mineralogist a G. Werner in 1789
Chemical composition: few pure ingredients, often containing various impurities
Category: natural elements - nonmetallic elements - Carbon Group
Crystal characteristics
Crystal system and space group: hexagonal crystal system, p63 / mmm
Unit cell parameters: A0 = 0.246nm, C0 = 0.670nm
It is a typical layered structure, in which carbon atoms are arranged in layers, and each carbon is equidistantly connected with the adjacent carbon. The carbon in each layer is arranged in a hexagonal ring. The carbon hexagonal rings of the upper and lower adjacent layers are displaced from each other in the direction parallel to the network plane and then stacked to form a layered structure. Different orientations and distances of displacement lead to different polytype structures. The distance between the carbon atoms in the upper and lower layers is much larger than that in the same layer (C-C spacing in layers = 0.142nm, C-C spacing between layers = 0.340nm)
Morphology: single crystals are often in sheet or plate shape, but complete ones are rare. Aggregates are usually scaly, massive and earthy
Color: iron black
Streak: bright black
Transparency: opaque
Luster: semi metallic luster
Hardness: 1-2
Cleavage and fracture: parallel cleavage pole complete EDM graphite material
Specific gravity: 2.21-2.26g/cm3
Specific surface area: 5-10m2 / g
Other properties: the sheet is flexible, slippery, easy to stain hands, and has good conductivity
Identification features: iron black, low hardness, a group of extremely complete cleavage, slippery feeling and hand dyeing; If the zinc particles wetted by the copper sulfate solution are placed on the graphite, copper spots can be separated out, but there is no such reaction on molybdenite similar to graphite.