What is High Purity Graphite Powder?
High Purity Graphite powder is a kind of mineral powder, the main component is carbon, it is soft, black and gray; it has a greasy feeling and can pollute the paper. The hardness is 1 to 2, and the hardness can be increased to 3 to 5 with the increase of impurities in the vertical direction. The specific gravity is 1.9 to 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 at room temperature are relatively stable, insoluble in water, dilute acid, dilute alkali and organic solvents; the material has high temperature resistance and electrical conductivity, and can be used as refractory material, conductive material, wear-resistant lubricating material.
The main features of High Purity Graphite Powder
Graphite powder is a substance with very sensitive chemical reaction. Its resistivity will change in different environments, that is, its resistance value will change, but one thing will not change. Graphite powder is a good non-metallic conductive substance. One, as long as the graphite powder is kept uninterrupted in an insulating object, it will be energized like a thin wire. However, the resistance value is not an accurate number, because the thickness of the graphite powder is different. The resistance value of graphite powder will be different in different materials and environments. Due to its special structure, graphite has the following special properties:
(1) High temperature resistant type: The melting point of graphite is 3850±50℃ and the boiling point is 4250℃. Even if it is burned by an ultra-high temperature arc, the weight loss is very small and the thermal expansion coefficient is also small. The strength of graphite increases with increasing temperature, and 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 ordinary non-metallic minerals. The thermal conductivity exceeds that of metal materials such as steel, iron, and lead. The thermal conductivity decreases with increasing temperature, and even at extremely high temperatures, graphite acts as a thermal 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 connected into very thin sheets.
(6) Thermal shock resistance: When graphite is used at room temperature, it can withstand severe changes in temperature without damage.
When the temperature changes suddenly, the volume of graphite changes little and no cracks occur.
The applications of High Purity Graphite Powder
1. As a refractory material Graphite and its products have the properties of high temperature resistance and high strength. They are mainly used in the metallurgical industry to manufacture graphite crucibles. In steel-making, graphite is often used as a protective agent for steel ingots and as the lining of metallurgical furnaces.
2. As a conductive material In the electrical industry, it is used to manufacture electrodes, brushes, carbon rods, carbon tubes, positive electrodes of mercury positive current devices, graphite gaskets, telephone parts, coatings for TV picture tubes, etc.
3. As a wear-resistant lubricating material Graphite is often used as a lubricant in the machinery industry. Lubricating oil often cannot be used under the conditions of high speed, high temperature and high pressure, while graphite wear-resistant materials can work at high sliding speed at (1) 200~2000 ℃ temperature without lubricating oil. Many equipment for conveying corrosive media widely use graphite materials to make piston cups, sealing rings and bearings. They do not need to add lubricating oil during operation. Graphite milk is also a good lubricant for many metal processing (wire drawing, tube drawing).
