Method of producing carbon-containing materials by electron beam

Details Method of producing carbon-containing materials by electron beam Method of producing carbon-containing materials by electron beam

1991-11-08

1994-03-22

Beck, Shrive

Coating processes

Direct application of electrical, magnetic, wave, or...

Pretreatment of coating supply or source outside of primary...

427577, 427580, 427586, 427596, 427122, 427249, 427294, B05D 100

Patent

active

052962741

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE ART

The present invention relates to the methods of producing materials and coatings in a vacuum and more particularly to a method of producing carbon-containing materials.


PRIOR ART

At present there exists a problem of producing carbon-containing materials and coatings with a high efficiency within a wide range of condensation temperatures, including low ones. The latter circumstance provides a possibility of extending the range of materials and supports, of varying the structure and properties of the materials and coatings produced within broad limits and, in the case of an ionic component being present in the vapour flow of carbon, of producing coatings and materials comprising metastable phases of carbon: diamond and carbin.
Known in the art is a method of depositing carbon coatings from a gas phase as a result of pyrolysis of carbon-containing substances, mainly hydrocarbons, on a hot surface (E. F. Chalykh, "Tekhnologiya Uglegraphitovykh Materialov"/`Tecgnology of Carbon-Graphite Materials`/, 1963, Metallurgizdat (Moscow), pp. 266-267). In this case the carbon deposition rate depends or the rate of the reaction of pyrolysis, as well as on the concentration of the gaseous mixture, on the rate of its feed to the reaction zone, and on the temperature of the surface being coated. Under optimal process conditions the rate of carbon depositing is high and may reach 1000 .mu.m/h. However, the limiting factor in the process is the temperature of the support, this being decisive for the lower limit of this parameter, amounting to 900.degree. C. The latter circumstance limits both the range of materials to which it is possible or at least expedient to apply a coating and the possibilities of varying the structures of the condensate. Lowering of the support temperature or increasing of the concentration of hydrocarbons in the reaction zone (for increasing the rate of the process) leads to the formation of loose sooty deposits and to an increase of hydrogen content in the carbon layer, whereby the quality of the coating is impaired appreciably.
Methods are known in the art, which make it possibly to apply a dense carbon coating practically at any temperature of the support. In these methods the technology of physical deposition from the vapour phase (PVD) is employed.
For example, a method of producing carbon coatings is known in the art (V. E. Strelnitsky, V. G. Padalka, S. I. Vakula, "Nekotorye svoistva almazopodobnykh uglerodnykh plenok, poluchennykh pri kondensatsii plamennogo potoka v usloviyah ispol'zovaniya vysokochastotnogo potentsiala"/`Some Properties of Diamond-Like Carbon Films Produced in Condensation of Plasma Flow Under the Conditions of Using High-Frequency Potential`/--Zhurnal Tekhnicheskoi Fiziki, 1978, vol. 48, Issue 2, pp. 377-381), which pertains to the PVD technology. In the given method the source of carbon vapours is a self-sustaining arc discharge, developing in the vapours of an eroding graphite cathode. The method makes it possible to produce coatings within a wide range of support temperatures, including water-cooled supports; this, in combination with an ionic component in the vapour flow, enables the production of coatings comprising metastable phases of carbon (diamond, carbin). The rate of applying the coating is up to 10 .mu.m/h. Nevertheless, a specific feature of the process is the inevitable presence of graphite fragments in the carbon vapours. This circumstance is brought about by specific features of the erosion of the cold graphite cathode in the cathode microscopic spots of the vacuum arc, in which the current density reaches 10.sup.5 to 10.sup.6 A/cm.sup.2. The surface of the graphite cathode is in the solid state, the convective heat transfer is thus absent, and this fact contributes to local overheating of microscopic areas of the cathode surface and to the origination of microscopic spots. Said circumstance in combination with the specific features of the graphite structure (laminated structure with weak bonds between the layers) leads to ejection of g

REFERENCES:
patent: 2583671 (1954-07-01), Findlay et al.
patent: 3347701 (1967-10-01), Yamagishi et al.
patent: 3470978 (1969-01-01), Adams
patent: 4762975 (1988-08-01), Mahoney et al.
patent: 4877677 (1989-10-01), Hirochi et al.
patent: 4919968 (1990-04-01), Buhl et al.

Affiliated with

Also associated with

Rating

Method of producing carbon-containing materials by electron beam does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of producing carbon-containing materials by electron beam, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of producing carbon-containing materials by electron beam will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-435429