How graphite crucibles and graphite rotor blades are made: the difference in technology
Anyone who has held a pencil in their hands is familiar with the ability of graphite to wear evenly. But not everyone knows that graphite in industry serves the exact opposite purpose - it reliably protects machine parts from wear.
Abrasion protection and resistance to overheating
Due to the fact that graphite has pronounced frictional and thermal properties, there are two directions of its use. The first is the production of bearings, seals, graphite turbine blades . The second - graphite crucibles - tanks for melting. Graphite is a popular solid lubricant. Due to its plasticity, the graphite mass tightly fills the grooves in the worn axles of the rotors, eliminates gaps in the mating parts. Graphite does not spread, does not splatter. This material is essential for the reliable operation of "clean" equipment - laboratory vacuum pumps and compressors of medical equipment.
The second distinctive property of graphites is heat resistance. Industrial graphites retain their structure at a temperature of 2000 o , and parts operating in chemically active environments withstand a load of 500 °. Graphite does not react with acids and alkalis. The melting point in metals is much higher than the characteristics of the material itself.
Graphite and graphite products
Graphites are used in pure and combined form. Natural graphites for industrial use are classified according to GOST 17022-81. Finished products from this material are called "graphite". In addition to pencil types, there are lubricating graphites, accumulators, foundry and electric coal.
Composite graphites are obtained by graphitization. There are two types of composites.
- Graphite oils are suspensions containing a suspension of graphite.
- Carbofiber - composite materials that are obtained by sintering reinforcing fibers in a methane environment. The base is graphitized at a temperature of 2500-3000 °.
Graphite-containing composites are 5–10 times better than solid graphite in abrasion and impact resistance. Wear-resistant parts are made from materials of this group. Graphite blades for compressors and vacuum pumps are widely used. Natural material is more suitable for making crucibles. Pure graphite, although it has a fragile structure, but its products last longer - graphite crucibles less susceptible
