IDEA #4KC7CZ Electron Beam Technology And Equipment For Producing Carbon-Based Materials With An Amorphous, Nano- And Micro-Sized Structure

THE SCIENCE AND TECHNOLOGY CENTER IN UKRAINE ELECTRON BEAM TECHNOLOGY AND EQUIPMENT FOR PRODUCING CARBON%BASED MATERIALS WITH AN AMORPHOUS, NANO% AND MICRO%SIZED STRUCTURE Description Technology is based on the method of electron beam evap(cid:28) oration of carbon (graphite) using a liquid pool of tungsten and subsequent condensation of the vapour flow, which was suggested by us and patented in Ukraine and the USA (US Patent #5296274, cl. B05D 1/00 Movchan B.A. and others. "Method of producing carbon(cid:28)containing materials by electron beam vacuum evaporation of graphite and sub(cid:28) sequent condensation"). Evaporation is performed as fol(cid:28) lows: a plano(cid:28)cylindrical tungsten tablet 5–10 mm high is placed on the end face of a cylindrical graphite block of 50–100 mm diameter and specified length. The tablet is melted by the electron beam and forms a "hot pool". A con(cid:28) tinuous transport process of carbon dissolution in the liq(cid:28) uid pool volume, subsequent evaporation from the pool surface and formation of an intensive vapour flow of car(cid:28) bon atoms (clusters) is established. Tungsten practically does not evaporate. Located near the above(cid:28)mentioned carbon evaporation source is the second independent tra(cid:28) ditional source of electron beam evaporation of metallic and non(cid:28)metallic materials, which are added to the main vapour flow of carbon by evaporation, if required (The third evaporation source can also be used). This method has been recently improved by applying the technique of reflection of the vapour flow of carbon (or carbon plus additives) from surfaces (mirrors) heated up to high tem(cid:28) peratures (1000–1800°C), to form in space vapour flows of a specified orientation and more uniform in terms of com(cid:28) position, structure and energy of the particles. This improvement is required at subsequent deposition of the vapor flow and "engineering" of the specified coating structure. Vapour flow ionization and bleeding gases into the vacuum chamber can be used as additional technologi(cid:28) cal parameters for controlling the deposition process and condensate structure. Temperature of the deposition sur(cid:28) face is one of the main technological parameters, control(cid:28) ling the condensate structure. Rate of evaporation of a graphite block of 70 mm diameter is equal to 1.0–1.1 kg/h. Innovative Aspect and Main Advantages Electron beam technology differs from the currently avail(cid:28) able methods of arc and laser evaporation of carbon by availability of many parameters for fine adjustment of the main stages of the evaporation process, vapour flow forma(cid:28) tion and its condensation, namely: 1. Area, average values of evaporation rate and tempera(cid:28) ture of atoms (molecules) evaporated from the tungsten "hot pool". 2. Temperature, composition and molecular structure of the vapour flow after reflection from the heated surfaces, vapour flow ionization, bleeding gases and using additives of inorganic and organic substances, including catalysts of the growth of macromolecular structures of the type of nanotubes and fullerenes. 42 Temperature of the condensation surface of an oriented vapour flow in the range from room temperature to 1000–1200°C and respective structures 3. from amorphous to nano(cid:28) and micro(cid:28)sized. Possibility of producing macromolecular (fullerenes, nanotubes) and diamondlike structures, carbides and composite materials (coatings) on their base is shown. A pilot production elec(cid:28) tron beam unit of up to 250 kW power adapted to the above technology variants is available. Areas of Application:Electronics and optoelectronics, medicine, chemical technology, instrument and mechanical engineer(cid:28) ing. Stage of Development Technology and equipment have been patented, experi(cid:28) mental facilities are available, and a demonstration can be done. Contact Details Іnternational Center for Electron Beam Technologies of E.O.Paton Electric Welding Institute of NASU 68, Gorky str., Kiev(cid:28)150, 03150, Ukraine Yakovchuk Konstantin Tel. +38 044 289(cid:28)2176Fax +38 044 287(cid:28)3166 E(cid:28)mail: yakovchuk@paton(cid:28)icebt.kiev.ua http://www.paton(cid:28)icebt.kiev.ua Pic. 1. Examples of special structures of carbon condensates: nanotubes (a) and spheres (b) SCIENCE AND INNOVATION. Special Issue, 2007