Quality Control

Graphite Quality Testing

Overview of testing

Graphite is an allotrope of carbon, a transitional crystal between atomic crystals, metal crystals and molecular crystals.Generally gray black, soft texture, greasy feeling.Enhanced heat in air or oxygen that burns and produces carbon dioxide.Strong oxidizing agents will oxidize it into organic acids.Used as antiwear agent and lubricating material, making crucible, electrode, dry battery, pencil lead.The scope of graphite detection: natural graphite, dense crystalline graphite, flake graphite, cryptocrystalline graphite, graphite powder, graphite paper, expanded graphite, graphite emulsion, expanded graphite, clay graphite and conductive graphite powder, etc.

Special properties of graphite

1. high temperature resistance: the melting point of graphite is 3850±50℃, even after ultra-high temperature arc burning, the weight loss is very small, thermal expansion coefficient is very small.The strength of graphite increases with the increase of temperature. At 2000℃, the strength of graphite doubles.
2. conductive, thermal conductivity: the conductivity of graphite is one hundred times higher than the general non-metallic ore.The thermal conductivity of steel, iron, lead and other metal materials.Thermal conductivity decreases with the increase of temperature, even at very high temperature, graphite into insulation;
3. lubricity: the lubrication performance of graphite depends on the size of graphite flake, flake, friction coefficient is smaller, the lubrication performance is better;
4. chemical stability: graphite at room temperature has good chemical stability, acid resistance, alkali resistance and organic solvent corrosion resistance;
5. plasticity: graphite toughness is good, can be crushed into a very thin sheet;
6. thermal shock resistance: graphite at room temperature when used can withstand drastic changes in temperature without damage, temperature mutation, the volume of graphite change little, will not crack.

Two, detection indicators

1. composition analysis: fixed carbon, moisture, impurities, etc.;
2. Physical performance testing: hardness, ash, viscosity, fineness, particle size, volatilization, specific gravity, specific surface area, melting point, etc.
3. mechanical properties testing: tensile strength, brittleness, bending test, tensile test;
4. chemical performance testing: water resistance, durability, acid and alkali resistance, corrosion resistance, weather resistance, heat resistance, etc
5. Other testing items: electrical conductivity, thermal conductivity, lubrication, chemical stability, thermal shock resistance