Graphite powder

Graphite powder is soft and dark gray; it has a greasy feel and can stain paper.The hardness is 1~2, and the hardness can increase to 3~5 with the increase of impurities in the vertical direction.The specific gravity is 1.9~2.3.Under the condition of isolating oxygen, its melting point is above 3000℃, which is one of the most temperature-resistant minerals.

The chemical properties of graphite powder are relatively stable at room temperature, insoluble in water, dilute acid, dilute alkali and organic solvents; it reacts with oxygen at different high temperatures to generate carbon dioxide or carbon monoxide; among halogens, only fluorine can directly react with elemental carbon; under heating , Graphite powder is easier to be oxidized by acid; at high temperature, it can also react with many metals to form metal carbides, which can smelt metals at high temperatures.

Special nature:

1) High temperature resistant type: The melting point of graphite is 3850±50℃, and the boiling point is 4250℃. Even if burned by ultra-high temperature arc, the weight loss is very small, and the thermal expansion coefficient is also very small.The strength of graphite increases with the increase of temperature. At 2000°C, the strength of graphite doubles.

2) Electrical and thermal conductivity: The electrical conductivity of graphite is one hundred times higher than that of general non-metallic minerals.The thermal conductivity exceeds that of metal materials such as steel, iron, and lead.Thermal conductivity decreases with increasing temperature, even at extremely high temperatures, graphite becomes an insulator.

3) Lubricity: The lubricating performance of graphite depends on the size of the graphite flakes. The larger the flakes, the smaller the friction coefficient and the better the lubricating performance.

4) Chemical stability: Graphite has good chemical stability at room temperature, and is resistant to acid, alkali and organic solvent corrosion.

5) Plasticity: Graphite has good toughness and can be grown into very thin flakes.

6) Thermal shock resistance: Graphite can withstand drastic changes in temperature without being damaged when used at room temperature. When the temperature changes suddenly, the volume of graphite will not change much and no cracks will occur.

Applications

1. Used as refractory material: Graphite and its products have the properties of high temperature resistance and high strength. It is mainly used in the metallurgical industry to make graphite crucibles. In steelmaking, graphite is often used as a protective agent for steel ingots and as a lining for metallurgical furnaces.

2. As a conductive material: used in the electrical industry to make electrodes, brushes, carbon rods, carbon tubes, positive electrodes of mercury positive current devices, graphite washers, telephone parts, coatings for television picture tubes, etc.

3. As a wear-resistant lubricating material: Graphite is often used as a lubricant in the machinery industry.Lubricating oil can not be used under high-speed, high-temperature, and high-pressure conditions, while graphite wear-resistant materials can work at high sliding speeds at a temperature of (1) 200~2000 ℃ without lubricating oil.Many equipment that transports corrosive media widely use graphite materials to make piston cups, seals and bearings. They do not need to add lubricating oil when they are running.Graphite emulsion is also a good lubricant for many metal processing (wire drawing, pipe drawing).