DE102011050112A1 - Producing coated particle, comprises evaporating a first starting material, and condensing below formation of particles, which are subsequently coated below supply of a second starting material - Google Patents

Producing coated particle, comprises evaporating a first starting material, and condensing below formation of particles, which are subsequently coated below supply of a second starting material

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Publication number
DE102011050112A1
DE102011050112A1 DE102011050112A DE102011050112A DE102011050112A1 DE 102011050112 A1 DE102011050112 A1 DE 102011050112A1 DE 102011050112 A DE102011050112 A DE 102011050112A DE 102011050112 A DE102011050112 A DE 102011050112A DE 102011050112 A1 DE102011050112 A1 DE 102011050112A1
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Germany
Prior art keywords
particles
starting material
10a
coating
zone
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DE102011050112A
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German (de)
Inventor
Dr. de Vries Edgar
Maik Liebau
Ralf Uhlemann
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INDUSTRIEANLAGEN BETRIEBSGES
Industrieanlagen-Betriebsgesellschaft mbH
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INDUSTRIEANLAGEN BETRIEBSGES
Industrieanlagen-Betriebsgesellschaft mbH
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Priority to DE102010016811 priority Critical
Priority to DE102010016811.4 priority
Application filed by INDUSTRIEANLAGEN BETRIEBSGES, Industrieanlagen-Betriebsgesellschaft mbH filed Critical INDUSTRIEANLAGEN BETRIEBSGES
Priority to DE102011050112A priority patent/DE102011050112A1/en
Publication of DE102011050112A1 publication Critical patent/DE102011050112A1/en
Application status is Withdrawn legal-status Critical

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    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
    • C23C16/4417Methods specially adapted for coating powder
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER
    • B22F1/00Special treatment of metallic powder, e.g. to facilitate working, to improve properties; Metallic powders per se, e.g. mixtures of particles of different composition
    • B22F1/02Special treatment of metallic powder, e.g. to facilitate working, to improve properties; Metallic powders per se, e.g. mixtures of particles of different composition comprising coating of the powder
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/26Deposition of carbon only

Abstract

The invention relates to a process for the preparation of coated particles (10b) having a mean particle size of at most 100 nm, in which at least a first starting material (11) is evaporated in a DC plasma and condensed to form particles (10a) a second starting material (13) are subsequently coated. The method is characterized in that the second starting material (13) comprises at least one hydrocarbon-containing gas and the particles (10a) are coated by chemical vapor deposition with at least one layer (12) of carbon.

Description

  • The invention relates to a process for the production of coated particles having the features of the preamble of claim 1. The invention further relates to an apparatus for producing coated particles.
  • A method and a device of the type mentioned are, for example US 2005/0217421 A1 known.
  • On the one hand, on the one hand due to the nanoscale particles, so for particles with a maximum average particle size of 100 nm, very large surface area ratio resulting advantages or special properties on the other hand are the tendency of nanoscale particles for agglomeration and increased grain growth at elevated temperatures, eg Sintering processes. The special properties of nanoscale particles are usually lost. To avoid the agglomeration and the unwanted grain growth, it is therefore known to coat nanoscale particles. As coating materials, ceramic materials or polymers are used. The production of so-called core-shell nanoparticles with organic polymer shells takes place in separate process steps, because the coating of finely divided particles with organic materials requires low-temperature processes, in particular in temperature ranges below 200 ° C. These require relatively long cooling times and thus increase the risk of agglomeration in the reactor. Coatings with polymers, in addition to the condensation on surfaces also cause the polymerization, which takes place, for example, by supplying heat or under UV radiation. As a result, relatively long residence times must be realized in the downstream reactor.
  • From the document mentioned above, a method and an apparatus for the production of titanium dioxide nanoparticles are known, which are coated with methyl methacrylate (MAA). Furthermore, the document discloses the coating with fluorine compounds and diethylzinc. Titanium tetrachloride is used as the starting material for the preparation of the titanium dioxide nanoparticles, which is fed together with an oxidizing gas to an RF plasma, so that a metal oxide vapor is formed. The metal oxide vapor is rapidly cooled in a cooling zone to yield the desired titanium dioxide nanoparticles having a mean particle size of 43.3 nm. The particles thus obtained are further cooled and then coated.
  • Due to the further cooling required for the coating and the associated extended residence time in the reactor, the risk of agglomeration of the particles mentioned at the outset exists.
  • DE 10 2006 046 806 A1 discloses a process for the production of coated particles, in which a raw material mixture is introduced into a hot gas stream in a thermal reactor with pulsating combustion and thus particles having a particle size of about 50 nm are obtained. The particles are coated with silica or alumina. For the coating, a further mixture of raw materials is finely dusted into the hot gas stream. Other methods in which nanoscale particles are coated with silicon dioxide or with aluminum oxide and with zirconium dioxide are in DE 10 2006 046 806 A1 referred to, to which reference is hereby made.
  • DE 11 2005 001 429 T5 discloses a method of forming nanoparticles. In this case, a capacitive RF plasma is generated, which forms the essential prerequisite for the production of the nanoparticles. With this method, a particularly high plasma density, ionization rate and gas temperature is achieved, which is advantageous for the production of nanoscale particles. The known method is suitable for producing core-shell particles. For this purpose, a plasma reactor and a gas phase reactor are connected in series. In the context of this combined process, the production of metal oxide, metal and metal nitride coatings is disclosed. In addition, in the context of deposition from the gas phase, the coating of CdS nanoparticles with a sulfur layer is disclosed. The coating with carbon is not disclosed in connection with the vapor deposition.
  • Out DE 42 17 328 C1 For example, the coating of filaments with a graphite layer by a CVD method is known. Essential for this process is the gas flow in a closed circuit. A coating of nanoparticles is not possible with this method. Another method of coating filaments with carbon is out DE 694 02 352 T2 known. This method is also not suitable for coating nanoparticles.
  • The invention is based on the object to provide a method and an apparatus for producing coated particles having an average particle size of at most 100 nm, wherein the agglomeration of the particles should be avoided or at least reduced and the surface properties of the particles to be modified.
  • According to the invention, this object is achieved with regard to the method by the subject matter of Claim 1, with regard to the device by the subject-matter of claim 11.
  • The invention is based on the idea to provide a process for the production of coated particles having an average particle size of at most 100 nm, in which at least a first starting material is vaporized and condensed to form particles, which are then coated by supplying a second starting material. The second starting material comprises at least one hydrocarbon-containing gas. The particles are coated by chemical vapor deposition with at least one layer of carbon. The evaporation of the first starting material is carried out by a DC plasma. The coating of the particles with carbon on the one hand has the advantage that the agglomeration of the particles is reduced or even completely prevented. Moreover, the invention provides the prerequisite for the production of conductive nanoscale particles. Such conductive nanoscale particles can be used for example as composite materials for electrically conductive polymers having antistatic properties. The conductive nanoscale particles may also be used to form conductive ink or for screen printing processes.
  • Since the carbon coating can be carried out by chemical vapor deposition (CVD) at relatively high temperatures, it is not necessary to cool the particles, as in the case of coating with polymers. This reduces the residence times of the particles in the reactor.
  • A suitable apparatus for carrying out the method according to the invention comprises a reactor comprising at least two zones, wherein a first zone at least one supply for a first starting material, means for evaporation of the first starting material by DC plasma and means for condensation of the first starting material to form particles having an average particle size of at most 100 nm. The second zone for coating the particles has at least one feed for a second starting material. The feed for the second feedstock is connected to a container filled with a hydrocarbon-containing gas. The second zone can be heated in such a way that sufficient thermal energy can be supplied to the second zone for the pyrolysis of the carbon-containing gas. The first and second zones are coupled in such a way that the particles obtainable in the first zone can be fed to the second zone for coating with pyrolyzed carbon in a continuous operation.
  • Furthermore, the particles which can be produced with the method according to the invention or the device according to the invention are claimed, d. H. Particles having an average particle size of at most 100 nm coated with at least one layer of carbon.
  • Preferred embodiments of the invention are specified in the subclaims.
  • Conveniently, the production and coating of the particles takes place in a continuous operation. This further reduces the residence time of the particles in the reactor. Preferably, the particles are mixed immediately after condensation with a hydrocarbon-containing gas. This further shortens the residence time in the reactor.
  • Preferably, the second feedstock comprises gaseous reactants, such as ethene and / or methane and / or acetylene, or liquid reactants, such as toluene, alcohol or benzene, which are evaporated prior to coating the particles. These gases are particularly well suited as starting material or starting material for the chemical vapor deposition. Also possible is the supply of the second starting material as liquid reactants, which are evaporated before mixing with the particles or before coating and form a hydrocarbon-containing gas in the context of the invention.
  • In a preferred embodiment, the carbon is obtained by pyrolysis of the second hydrocarbonaceous feedstock. In a further preferred embodiment, the particles are coated with at least one graphite-like layer of carbon or with at least one DLC layer. As a result, new properties of the products produced from the coated particles can be realized, for example conductive particles with a graphite-like coating. The particles provided with a DLC (diamond-like-carbon) layer are not conductive. Further advantageous properties of the layer of carbon are its high thermal stability, its thermodynamic compatibility, for example, to silicon-based particles and their relatively low production costs, for example, in contrast to the known titanium nitride coating.
  • Preferably, the coating of the particles is carried out at a temperature of at least 500 ° C, in particular from about 500 ° C to 1200 ° C. This temperature range is particularly suitable for the formation of graphitic, conductive carbon layers. If the reactant is subjected to such high temperatures before coating that it completely dissociated, electrically non-conductive carbon layers are deposited at high temperatures that do not contain hydrogen. These layers are so-called DLC (diamond like carbon) layers, which are usually produced in plasma reactors by means of a CVD or PVD process.
  • If the layer of carbon is not conductive, the function of the layer is in the foreground to reduce the agglomeration tendency of the particles. Coating the particles with non-conductive layers of carbon may alternatively be done at a temperature of less than about 500 ° C for deposition of the DLC layers.
  • Particularly suitable for combination with the layer of carbon are silicon-containing particles, such as silicon and / or silicon nitride particles suitable.
  • The thermal energy for coating the particles can be supplied externally. This has the advantage of easy control of the power supply. Alternatively, the thermal energy for coating the particles can be generated by the thermal energy supplied for the evaporation of the first starting material. Thus, the thermal energy of, for example, the plasma is used for the pyrolysis of the hydrocarbon-containing gases. This has the advantage that the process is particularly energy-efficient. In a further embodiment of the method, the particles are coated with a single layer or with a plurality of different layers, so that different functions, in particular multifunctional particles, are obtainable.
  • The invention will be explained in more detail by means of embodiments with reference to the accompanying drawings with further details. In this show
  • 1 a longitudinal section through a schematically illustrated apparatus for producing coated particles according to an embodiment of the invention and
  • 2 the process step of coating a particle with pyrolyzed carbon.
  • In 1 the embodiment of an apparatus for carrying out the method for producing coated particles is shown. The device has a reactor 20 with at least two zones 21 . 22 on. The first zone 21 serves to produce the nanoscale particles. The first zone 21 subsequent second zone 22 The coating is used in the first zone 21 produced particles 10a ,
  • For producing the particles, the first zone comprises 21 at least one feed 23 for a first starting material 11 , The first zone 21 further comprises means for evaporation 24 of the first starting material 11 , In the embodiment according to 1 is a plasma generator with a plasma nozzle 27 provided for generating a DC plasma. The plasma nozzle 27 includes a centrally located cathode 28 and two concentrically arranged anodes 29 . 30 , The closer to the cathode 28 arranged first anode 29 serves in the form of a pilot anode to ignite an arc between the cathode 28 and the first anode 29 , The arc is passed through the remotely located second anode 30 extended. With the tip of the plasma nozzle 27 is a tubular nozzle extension 31 connected gas-tight. The extended arc between the cathode and the second anode 30 extends over the entire length of the nozzle extension 31 , In the embodiment according to 1 is the feed 23 for the first starting material 11 into the plasma nozzle 27 integrated. Other possibilities of supply, for example a separate feed for the first starting material, is possible. For the structure and details of the plasma nozzle 27 is attributed to the applicant German application 10 2010 015 891 directed.
  • Instead of the plasma generator according to 1 For example, a conventional plasma generator can be used which is capable of transmitting the arc over a defined reactor length, ie, the nozzle extension 31 is waived. In this case, the first raw material evaporates 11 supplied microscale particles already in the burner area. In the embodiment according to 1 are also microscale particles as precursor or as the first starting material 11 fed.
  • Instead of the DC plasma, an inductively coupled RF plasma or a microwave plasma can be used or correspondingly adapted plasma generators. In general, it is possible to produce the nanoscale particles by plasma-assisted evaporation of a precursor, for example a microscale precursor or else a liquid or gaseous precursor.
  • The reactor 20 further comprises means for condensation 25 of the first starting material 11 , for example in the form of a cooling nozzle. The means of condensation 25 are designed so that sufficient cooling rates can be realized for the production of nanoscale particles. The parameters required for this purpose are known to the person skilled in the art.
  • To the first zone 21 or the means for condensation 25 of the first starting material 11 closes the second zone 22 for coating in the first zone 21 obtained particles 10a at. The second zone 22 includes at least one feed 26 for a second starting material 13 on. The second starting material 13 is a hydrocarbon-containing gas or a hydrocarbon-containing liquid. The supply is concrete 26 for the second starting material 13 connected to a container (not shown) filled with a hydrocarbon-containing gas or with a hydrocarbon-containing liquid. It is also possible to provide two, three or more than three feeders for different second feedstocks with at least one feed connected to the container with the hydrocarbonaceous gas. The feed for the second starting material 13 is the means of condensation 25 of the first starting material 11 in the direction of flow of the particles 10a respectively. 10b downstream. The second zone 22 is so heated that the second zone 22 the sufficient thermal energy can be supplied for the pyrolysis of the supplied carbon-containing gas or the carbonaceous liquids to be evaporated. This is the second zone 22 limiting reaction space actively heated. The wall 32 the second zone 22 associated heating 33 can be done for example by heat radiation. The heating of the reactor 20 by lamps has the advantage of faster heating and cooling rates. Alternatively, the reactor may be a second non-actively heated zone 22 exhibit. In this case, the thermal energy of the hot plasma gas is used for the decomposition of the hydrocarbon-containing gases, which are supplied in gaseous form or as liquid with subsequent evaporation.
  • The first and second zones 21 . 22 are coupled such that in the first zone 21 available particles 10a the second zone 22 for coating with pyrolyzed carbon in a continuous operation can be fed. This is followed by the second zone 22 directly to the first zone 21 on, so that from the cooling nozzle or generally from the means for condensation 25 exiting particles 10a directly into the second zone 22 be transferred. The transport of the particles in the reactor is carried out by the carrier gases. The second zone 22 can, for example, be designed as a tube furnace, in particular as a hot wall tube furnace
  • The with the device according to 1 feasible processes for the production of coated particles 10b works as follows:
    In the plasma nozzle 27 or in the immediate area in the flow direction after the plasma nozzle 27 become the particles supplied to the plasma from the first starting material 11 vaporizes and dissociates. By per se known gas phase condensation nanoscale particles are deposited, whose average particle size is at most 100 nm. The person skilled in the known parameters are known.
  • The plasma pressure can be from 0.5 bar to 1.5 bar, in particular 0.8 bar to 1.2 bar, in particular 0.9 bar to 1.1 bar, in particular atmospheric pressure. Low plasma pressures are possible, which are less than 0.5 bar.
  • The from the first zone 21 emerging uncoated particles 10a be in the second zone 22 by chemical vapor deposition (CVD) with at least one layer 12 made of carbon. An example of a coated particle 10b is in 2 shown. In practice, a complete coating is not always given. In this respect, at least partially coated particles produced by the process described and claimed are also covered by the invention. The one for the coating or the layer 12 Carbon used in the embodiment according to 1 by pyrolysis of the second hydrocarbonaceous starting material 13 receive. The pyrolysis takes place in the same reaction space, ie in the second zone 22 instead of how the coating.
  • In the method, the two method steps, namely the plasma-assisted production of the nanoscale particles and their coating are coupled in a system or in a process, so that an in-situ coating of the primary core particles can take place. The production and coating of the particles 10a thus takes place in a continuous operation. The coating of the particles 10a takes place by in situ reaction with pyrolyzed hydrocarbons, such as. As ethene, methane or acetylene at temperatures between 500 ° C and 1200 ° C. The upper limit of the temperature range may be 1,150 ° C, 1,100 ° C, 1,050 ° C, 1,000 ° C, 950 ° C or 900 ° C. The lower limit of the temperature range may be 550 ° C, 600 ° C, 650 ° C, 700 ° C, 750 ° C, 800 ° C or 850 ° C. The above lower and upper limits can be combined.
  • The coating can be carried out at process pressures of 0.5 bar to 1.5 bar, in particular 0.8 bar to 1.2 bar, in particular 0.9 bar to 1.1 bar, in particular at atmospheric pressure. These areas are disclosed in connection with the aforementioned temperature ranges.
  • In a specific embodiment, the coating in the second zone 22 at a process pressure of 1 bar, a temperature of 930 ° C, the supply of nitrogen with 9 slm, the feed of ethylene with 1 slm and a residence time of 60 seconds.
  • The coated particles 10b have graphitic, conductive layers of carbon.
  • In the conversion of, for example, methane to graphite, aromatic intermediate compounds are formed which can be more or less hydrogen-rich. Such intermediates occur in the gas phase. It is believed that the aromatic compounds favor the formation of graphitic layers due to the structural similarities (pi-electron backbone). The resulting layers are made of carbon. Residual hydrogen contents of up to 5% were measured. The hydrogen content depends on the reaction conditions, but also on a possible post-treatment of the layers, in which the coated particles are annealed.
  • In the context of the invention, therefore, carbon layers with a residual content of up to 5% hydrogen are regarded as layers of carbon, in particular if the layers are graphitic. Graphite-like are the layers because the formed structures are microcrystalline. However, there are no extended 2-dimensional structures as in graphite. The graphitic structure of the layers is u. a. underpinned by the fact that the layers are electrically conductive. The above-mentioned low hydrogen content is another difference from graphite.
  • Alternatively to the reaction of hydrocarbons in a hot wall reactor, as in 1 is shown, a plasma-controlled reaction at temperatures below 500 ° C is possible, whereby non-conductive carbon layers with high H 2 content (sp 3 hybridization) are generated.
  • In addition to the in 2 monolayers in which only one reactant reacts chemically with the surface, it is also possible to prepare multilayers, for example by cyclic procedures, in which at least one further reactant or more reactants stratified onto the particles 10a or the precoated particles 10b be applied. This allows the production of functionalized nanoscale particles.
  • The particles which can be produced by the process according to the invention can be used, for example, in the solar industry, microelectronics, environmental technology, as well as in the production of Li ion batteries, as sintering additives or as novel fuels.
  • The invention will be further disclosed in connection with the following examples
    • 1. Process for producing coated particles ( 10b ) having an average particle size of at most 100 nm, in which at least a first starting material ( 11 ) and to form particles ( 10a ) condensed, with the supply of a second starting material ( 13 ) are subsequently coated, characterized in that the second starting material ( 13 ) comprises at least one hydrocarbon-containing gas and the particles ( 10a ) by chemical vapor deposition with at least one layer ( 12 ) are coated from carbon.
    • 2. Method according to Example 1, characterized in that the production and the coating of the particles ( 10a ) in a continuous operation.
    • 3. Method according to one of the preceding examples, characterized in that the particles ( 10a ) are mixed with the hydrocarbon-containing gas immediately after condensation.
    • 4. Method according to one of the preceding examples, characterized in that the second starting material ( 13 ) gaseous reactants, such as ethene and / or methane and / or acetylene, or liquid reactants, such as toluene, alcohol or benzene, which before coating the particles ( 10a ) are evaporated.
    • 5. The method according to any one of the preceding examples, characterized in that the carbon by pyrolysis of the second hydrocarbon-containing starting material ( 13 ).
    • 6. Method according to one of the preceding examples, characterized in that the particles ( 10a ) with at least one graphite-like layer ( 12 ) of carbon or at least one DLC layer ( 12 ) are coated.
    • 7. Method according to one of the preceding examples, characterized in that the coating of the particles ( 10a ) at a temperature of at least 500 ° C, in particular from 500 ° C to 1,200 ° C.
    • 8. Method according to one of Examples 1 to 4, characterized in that the layer ( 12 ) of carbon is not conductive.
    • 9. Method according to one of Examples 1-4 and Example 8, characterized in that the coating of the particles ( 10a ) at a temperature of less than 500 ° C.
    • 10. The method according to any one of the preceding examples, characterized in that the particles ( 10 ) comprise silicon-containing particles, such as silicon and / or silicon nitride particles.
    • 11. Method according to one of the preceding examples, characterized in that the evaporation of the first starting material ( 11 ) is effected by a plasma, in particular a DC plasma, an inductively coupled RF plasma or a microwave plasma.
    • 12. Method according to one of the preceding examples, characterized in that the thermal energy for coating the particles ( 10a ) is supplied externally.
    • 13. Method according to one of the preceding examples, characterized in that the thermal energy for coating the particles ( 10a ) by the evaporation of the first starting material ( 11 ) supplied thermal energy is generated.
    • 14. Method according to Example 13, characterized in that the thermal energy for coating the particles ( 10a ) is generated by the thermal energy contained in the plasma gases.
    • 15. Method according to one of the preceding examples, characterized in that the particles ( 10a ) with a single layer ( 12 ) or with several different layers ( 12 ) are coated.
    • 16. Device for producing coated particles ( 10b ) with a reactor ( 20 ), which has at least two zones ( 21 . 22 ), wherein a first zone ( 21 ) at least one feed ( 23 ) for a first starting material ( 11 ), Means for evaporation ( 24 ) of the first starting material ( 11 ) and means for condensation ( 25 ) of the first starting material ( 11 ) with the formation of particles ( 10a ) having an average particle size of at most 100 nm, a second zone ( 22 ) for coating the particles ( 10a ) at least one feed ( 26 ) for a second starting material ( 13 ) characterized in that the supply ( 26 ) for the second starting material ( 13 ) is connected to a container filled with a hydrocarbon-containing gas, and the second zone ( 22 ) is heated in such a way that the second zone ( 22 ) for the pyrolysis of the carbon-containing gas, sufficient thermal energy can be supplied, wherein the first and second zones ( 21 . 22 ) are coupled such that in the first zone ( 21 ) available particles ( 10a ) of the second zone ( 22 ) can be supplied for coating with pyrolyzed carbon in a continuous operation.
    • 17. Particles ( 10 ) having an average particle size of at most 100 nm and having at least one layer ( 12 ) are coated from carbon.
  • LIST OF REFERENCE NUMBERS
  • 10a
    uncoated particles
    10b
    coated particles
    11
    first starting material
    13
    second starting material
    20
    reactor
    21
    first zone
    22
    second zone
    23
    supply
    24
    Means for evaporation
    25
    Means for condensation
    26
    supply
    27
    plasma nozzle
    28
    cathode
    29
    first anode
    30
    second anode
    31
    nozzle extension
  • QUOTES INCLUDE IN THE DESCRIPTION
  • This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.
  • Cited patent literature
    • US 2005/0217421 A1 [0002]
    • DE 102006046806 A1 [0006, 0006]
    • DE 112005001429 T5 [0007]
    • DE 4217328 C1 [0008]
    • DE 69402352 T2 [0008]
    • DE 102010015891 [0027]

Claims (11)

  1. Process for producing coated particles ( 10b ) having an average particle size of at most 100 nm, in which at least a first starting material ( 11 ) and to form particles ( 10a ) condensed, with the supply of a second starting material ( 13 ) are subsequently coated, characterized in that the second starting material ( 13 ) comprises at least one hydrocarbon-containing gas and the particles ( 10a ) by chemical vapor deposition with at least one layer ( 12 ) are coated from carbon, wherein the evaporation of the first starting material ( 11 ) is done by a DC plasma.
  2. A method according to claim 1, characterized in that the process pressure during coating is 0.5 bar to 1.5 bar, in particular 0.8 bar to 1.2 bar, in particular atmospheric pressure.
  3. A method according to claim 1 or 2, characterized in that the production and the coating of the particles ( 10a ) in a continuous operation.
  4. Method according to one of the preceding claims, characterized in that the particles ( 10a ) are mixed with the hydrocarbon-containing gas immediately after condensation.
  5. Method according to one of the preceding claims, characterized in that the second starting material ( 13 ) gaseous reactants, such as ethene and / or methane and / or acetylene, or liquid reactants, such as toluene, alcohol or benzene, which before coating the particles ( 10a ) are evaporated.
  6. Method according to one of the preceding claims, characterized in that the carbon by pyrolysis of the second hydrocarbon-containing starting material ( 13 ).
  7. Method according to one of the preceding claims, characterized in that the particles ( 10a ) with at least one graphite-like layer ( 12 ) of carbon or at least one DLC layer ( 12 ) are coated.
  8. Method according to one of the preceding claims, characterized in that the coating of the particles ( 10a ) at a temperature of at least 500 ° C, in particular from 500 ° C to 1,200 ° C.
  9. Method according to one of claims 1 to 5, characterized in that the layer ( 12 ) is not conductive from carbon.
  10. Method according to one of claims 1-5 and claim 9, characterized in that the coating of the particles ( 10a ) at a temperature of less than 500 ° C.
  11. Apparatus for producing coated particles ( 10b ) with a reactor ( 20 ), which has at least two zones ( 21 . 22 ), wherein a first zone ( 21 ) at least one feed ( 23 ) for a first starting material ( 11 ), Means for evaporation ( 24 ) of the first starting material ( 11 ) by a DC plasma and means for condensation ( 25 ) of the first starting material ( 11 ) with the formation of particles ( 10a ) having an average particle size of at most 100 nm, a second zone ( 22 ) for coating the particles ( 10a ) at least one feed ( 26 ) for a second starting material ( 13 ), wherein the supply ( 26 ) for the second starting material ( 13 ) is connected to a container filled with a hydrocarbon-containing gas, and the second zone ( 22 ) is heated in such a way that the second zone ( 22 ) for the pyrolysis of the carbon-containing gas, sufficient thermal energy can be supplied, wherein the first and second zone ( 21 . 22 ) are coupled such that in the first zone ( 21 ) available particles ( 10a ) of the second zone ( 22 ) can be supplied for coating with pyrolyzed carbon in a continuous operation.
DE102011050112A 2010-05-05 2011-05-05 Producing coated particle, comprises evaporating a first starting material, and condensing below formation of particles, which are subsequently coated below supply of a second starting material Withdrawn DE102011050112A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DE102010016811 2010-05-05
DE102010016811.4 2010-05-05
DE102011050112A DE102011050112A1 (en) 2010-05-05 2011-05-05 Producing coated particle, comprises evaporating a first starting material, and condensing below formation of particles, which are subsequently coated below supply of a second starting material

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