Graphite powder chemical reaction is very sensitive material, in a different environment inside his resistivity would change, is also his resistance value will change, but one thing is not change, graphite powder is one of the non metal conductive material is very good, as long as the insulation inside the graphite powder to ensure uninterrupted, like a lines that will power, however, the resistance value is how much, this is not an accurate numerical number, because not the same as the thickness of graphite powder, graphite powder and materials used in environmental resistance of different values will be different.
Graphite is soft, black and gray; greasy feeling, can piece of paper pollution. Hardness is 1~2, along the vertical direction with the increase of impurities, its hardness can be increased to 3~5. The specific gravity is 1.9 ~ 2.3. Under isolated oxygen conditions, the melting point is above 3000 degrees Celsius and is one of the most refractory minerals. Under normal temperature and chemical properties of graphite is relatively stable, insoluble in water, dilute acid and dilute alkali and organic solvent; different high temperature reaction with oxygen, carbon dioxide or carbon monoxide; only in halogen fluorine can react directly with elemental carbon; under heating, the graphite powder is easy to be oxidized under high temperature, acid; but with many metal reaction, formation of metal carbides, can smelt metal at high temperature.
1) high temperature resistance: Graphite melting point of 3850 + 50 degrees, boiling point is 4250 degrees, even after the ultra-high temperature arc ignition, the weight loss is very small, the thermal expansion coefficient is very small. The strength of graphite increases with the increase of temperature, and the strength of graphite is doubled at 2000 degrees centigrade.2) conduction and thermal conductivity: the conductivity of graphite is one hundred times higher than that of ordinary non-metallic minerals. Heat conductivity exceeds steel, iron, lead and other metal materials. The coefficient of thermal conductivity decreases with increasing temperature, and even at extremely high temperatures, the graphite becomes hot.3) lubricity: the lubricity of graphite depends on the size of graphite scales. The larger the scale, the smaller the coefficient of friction and the better the lubricity.4) chemical stability: graphite has good chemical stability at room temperature, and can resist acid, alkali and organic solvent corrosion.5) plasticity: the toughness of graphite is good, but it can be a very thin slice.6) thermal shock resistance: when graphite is used at normal temperature, it can withstand the drastic change of temperature without damaging. When the temperature changes suddenly, the volume of graphite changes little and no cracks occur.
Graphite is a crystalline mineral of carbonaceous elements. Its crystalline framework is hexagonal layered structure. The distance between each network layer is 340pm, and the distance between the carbon atoms in the same network layer is 142pm;. Of the six Fang system with a complete lamellar cleavage. The cleavage surface is mainly based on molecular bonds, and has weaker molecular attraction, so its natural floatability is very good.Graphite and diamond, carbon 60, carbon nanotubes are carbon elements, they are allotropes.
