Graphitization


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graphitization

[‚graf·əd·ə′zā·shən]
(organic chemistry)
The formation of graphitelike material from organic compounds.

Graphitization

 

the formation (deposition) of graphite in iron, nickel, cobalt, and other metal alloys in which carbon is contained in the form of unstable chemical compounds, carbides. At high temperatures the carbide is completely replaced by graphite. The rate of graphitization increases upon a rise in temperature, as well as upon preliminary hardening, deformation, and irradiation.

Graphitization of steel usually adversely affects the mechanical properties of steel (it reduces the strength and plasticity). At the same time the graphite, which has lubricating properties, increases the durability of the articles. The graphitization of iron alloys is used in producing articles from cast iron and graphitic bearing and die steel. Silicon, or less frequently aluminum, is introduced into steel or iron to accelerate graphitization. The graphitization of a number of alloys (tool-cutting, spring, boiler, and other steels) reduces their operating quality and is undesirable. Graphitization can be arrested by introducing additives (chromium or manganese), which increase the stability of the carbides. The term “graphitization” is sometimes used to designate the formation of graphite in iron-carbon alloys that do not contain carbides. Graphite is separated from alloys that are supersaturated with carbon upon their solidification and subsequent cooling.

REFERENCES

Grafitizatsiia stali. Kiev, 1961.
Girshovich, N. G. Kristallizatsiia i svoislva chuguna ν otlivkakh. Moscow-Leningrad, 1966.
Krishtal, M. A., and E. G. Titenskii. Svoistva kovkogo chuguna. Moscow, 1967.

K. P. BUNIN and A. A. BARANOV

References in periodicals archive ?
3] bonds remains basically unchanged, illustrating that the graphitization tendency of ta-C film is inhibited.
They modified their sample preparation methods to accommodate liquid samples that bypass the time-consuming graphitization process.
The formation of graphitic layers in this experiment is considered to be due to the graphitization of hydrocarbons from wood char during its heating at 1,000[degrees]C.
The quantity of alloying elements contributes to the regulation of metallic [10-12] basis and process of graphitization.
Demineralization of vertebral samples was performed to isolate the organic portion (collagen) by dissolving the inorganic component that can increase carbon yield from the accelerator mass spectrometry (AMS) graphitization process (Brown et al.
We use artificial graphite produced through treatment at very high temperatures in our graphitization furnace at Omachi Plant, based on our proprietary powder processing technology.
The obvious proof is that graphitization of carbon black increases abrasion loss drastically (refs.
Van der Vlugt, Graphitization of Cast Iron as an Electro-biochemical Process in Anaerobic Soils, Water 18(16), p.
C, which induces graphitization of the material, changing the molecular bond structure.
a]) and graphitization degree (G) were calculated using the following relations (Guinier, 1963; Dong, 2008):
Because preliminary investigations had shown that the graphitization ability of the charge materials is essential to nucleation potential, all the heats were produced with 50% highly carbidic ductile iron returns in the charge.
For the first time on basis of scientifically substantiated methods experimental data were obtained (within temperature range up to 2500 [degrees]C), which significantly changed idea about character of distribution of the working zone temperatures of the graphitization furnace in space and time.