EP0630425A1 - Procede pour recouvrir du carbone renforce par fibres de carbone et produit ainsi obtenu - Google Patents

Procede pour recouvrir du carbone renforce par fibres de carbone et produit ainsi obtenu

Info

Publication number
EP0630425A1
EP0630425A1 EP93906488A EP93906488A EP0630425A1 EP 0630425 A1 EP0630425 A1 EP 0630425A1 EP 93906488 A EP93906488 A EP 93906488A EP 93906488 A EP93906488 A EP 93906488A EP 0630425 A1 EP0630425 A1 EP 0630425A1
Authority
EP
European Patent Office
Prior art keywords
carbon
layer
protective layer
reinforced carbon
crystalline
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP93906488A
Other languages
German (de)
English (en)
Inventor
Cornelia Strobel-Simon
Milan Hrovat
Heinrich Porth
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MTU Aero Engines GmbH
Nukem GmbH
Original Assignee
Nukem GmbH
MTU Motoren und Turbinen Union Muenchen GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nukem GmbH, MTU Motoren und Turbinen Union Muenchen GmbH filed Critical Nukem GmbH
Publication of EP0630425A1 publication Critical patent/EP0630425A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
    • C04B41/81—Coating or impregnation
    • C04B41/89—Coating or impregnation for obtaining at least two superposed coatings having different compositions
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
    • C04B41/52—Multiple coating or impregnating multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation
    • C04B41/526—Multiple coating or impregnation with materials having the same composition but different characteristics
    • C—CHEMISTRY; METALLURGY
    • C23—COATING 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
    • C23C—COATING 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
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical 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
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/34—Nitrides
    • C23C16/345—Silicon nitride
    • C—CHEMISTRY; METALLURGY
    • C23—COATING 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
    • C23C—COATING 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
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44—Chemical 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
    • C23C16/50—Chemical 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 using electric discharges
    • C23C16/511—Chemical 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 using electric discharges using microwave discharges
    • C—CHEMISTRY; METALLURGY
    • C23—COATING 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
    • C23C—COATING 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
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/04—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material
    • C23C28/044—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material coatings specially adapted for cutting tools or wear applications
    • C—CHEMISTRY; METALLURGY
    • C23—COATING 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
    • C23C—COATING 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
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/04—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material
    • C23C28/046—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material with at least one amorphous inorganic material layer, e.g. DLC, a-C:H, a-C:Me, the layer being doped or not
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/902—High modulus filament or fiber
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49229—Prime mover or fluid pump making
    • Y10T29/4927—Cylinder, cylinder head or engine valve sleeve making
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49229—Prime mover or fluid pump making
    • Y10T29/4927—Cylinder, cylinder head or engine valve sleeve making
    • Y10T29/49272—Cylinder, cylinder head or engine valve sleeve making with liner, coating, or sleeve
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/30—Self-sustaining carbon mass or layer with impregnant or other layer

Definitions

  • the invention relates to a method for coating carbon fiber reinforced carbon (CFC) with at least one layer.
  • CFC carbon fiber reinforced carbon
  • Carbon fiber reinforced carbon is characterized by high strength and very good toughness. A wide use of this material is, however, currently severely restricted due to a lack of oxidation resistance. In particular, use above 400'C without protective gas is hardly possible.
  • the present invention addresses the problem of providing a method for the coating of carbon fiber reinforced carbon having at least one layer so as to provide that a high oxidation resistance is also possible at higher temperatures, ie above 400 * C, but especially about 1.500'C .
  • the problem is solved according to the invention in that an adhesive layer made of amorphous SiN x is applied to the carbon fiber-reinforced carbon (CFC), to which in turn the layer resistant to oxidation at a temperature T OO'C is applied as a protective layer made of silicon compounds.
  • Crystalline S ' ⁇ N can be applied as a protective layer.
  • amorphous SiN or SiO 2 or a combination of these with kri ⁇ stallinem Si3N4 can be applied advantageously, so that by the inventive method, a carbon-fiber-Ko len ⁇ material is provided, which even at high temperatures, about 1500 * C, even over 1700 ' C is resistant to oxidation, ie it is suitable to be used in particular in aerospace technology. Consequently, components such as outlet cone in turbines, turbine housings, hot gas guide parts, combustion chambers, guide vanes or others can be produced from the carbon fiber-reinforced carbon refined according to the invention.
  • Amorphous silicon nitride is deposited as the adhesive layer in order to advantageously adapt the different coefficients of expansion of the carbon fiber-reinforced carbon and the protective layer to one another, since their coefficients of expansion have deviations that are too great from one another, so that there is otherwise the risk of cracks or flaking of the protective layer.
  • a micro-multipolar plasma such as DECR plasma (D stributed electron cyclotron resonance) can be used to deposit the adhesive layer made of amorphous SiN x .
  • the carbon fiber reinforced carbon is cleaned before the adhesive layer is applied. This can be done by bombardment by noble gas ions such as argon ions of a plasma preferably at a temperature above 200 * C and preferably at a pressure lower
  • the application of the adhesive layer is facilitated by cleaning.
  • a microwave-excited plasma is preferably used for cleaning.
  • the carbon fiber-reinforced carbon should have an electrical potential (BIAS) of at least 20 V, preferably from 60 V to 150 V.
  • the protective layer containing silicon nitride should be applied under or essentially avoiding stable diimides.
  • dichlorosilane and ammonia in a ratio of 1: 2 to 1: 8, 20, preferably 1: 5, are used as process gases, hydrogen being used as the carrier gas.
  • the crystalline silicon nitride layer is deposited at a pressure of less than 5 hPa and 25, preferably at a temperature between 1000'C and 1100'C.
  • the invention relates to a carbon fiber reinforced carbon, in particular determined as a material for use in aerospace engineering, the carbon fiber reinforced carbon being distinguished in that the carbon fiber reinforced carbon has an outer protective layer which has a high resistance to oxidation is coated from crystalline silicon nitride, an adhesive layer being arranged between the protective layer and the carbon fiber reinforced carbon, the expansion coefficient of which lies between that of the protective layer and that of the carbon fiber reinforced carbon.
  • An outlet cone of a turbine made of carbon-fiber-reinforced carbon (CFC) was introduced into a plant for plasma-assisted chemical vapor deposition (PECVD plant), in which the workpiece was a multi-multipolar-distributed plasma at a pressure of 5 x 10 'hPa exposed to a temperature of 500 * C to be shot with argon ions over a period of 10 minutes.
  • the workpiece was at a BIAS potential of 60 V. The workpiece was cleaned by this process step.
  • the workpiece provided with the adhesion promoter layer was then introduced into a CVD system in order to apply a crystalline Si3N4 protective layer.
  • SiH2Cl2 and NH3 were also used as process gases. Since in the reaction of dichlorosilane and ammonia, diimide, Si (NH) 2 »is initially formed, from which silicon nitride is formed in two further stages by the release of ammonia, care must be taken to ensure that the reaction is complete in preferably -S ⁇ 3N4 and not diimides be deposited.
  • the adhesion promoters is introduced mediate layer having workpiece into the reaction chamber, in order then in the CVD process at a temperature of 1050 * C and a process pressure of 2.5 hPa, the process gases of dichlorosilane and ammonia in a ratio of 1: 5 to introduce. H2 used as carrier gas. With these parameters, a deposition rate of 1 ⁇ m min "can be achieved.
  • the workpiece is then exposed to the process gases for the deposition of the silicon nitride protective layer in the reaction space for 60 minutes.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Metallurgy (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Ceramic Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Structural Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Chemical Vapour Deposition (AREA)

Abstract

On propose un procédé visant à rendre stable à l'oxydation du carbone renforcé par fibres de carbone. Selon ce procédé, une couche de SiNx amorphe ayant un pouvoir adhésif, est appliquée sur le carbone renforcé par fibres de carbone. Cette couche est elle-même recouverte d'une couche résistant à l'oxydation et servant de revêtement protecteur, à une température T, T étant > 400 °C, réalisée de préférence en Si3N4.
EP93906488A 1992-03-09 1993-03-06 Procede pour recouvrir du carbone renforce par fibres de carbone et produit ainsi obtenu Withdrawn EP0630425A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4207380 1992-03-09
DE4207380 1992-03-09
PCT/EP1993/000508 WO1993018203A1 (fr) 1992-03-09 1993-03-06 Procede pour recouvrir du carbone renforce par fibres de carbone

Publications (1)

Publication Number Publication Date
EP0630425A1 true EP0630425A1 (fr) 1994-12-28

Family

ID=6453558

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93906488A Withdrawn EP0630425A1 (fr) 1992-03-09 1993-03-06 Procede pour recouvrir du carbone renforce par fibres de carbone et produit ainsi obtenu

Country Status (4)

Country Link
US (1) US5489422A (fr)
EP (1) EP0630425A1 (fr)
JP (1) JPH07504713A (fr)
WO (1) WO1993018203A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5682676A (en) * 1994-09-22 1997-11-04 Yamaha Hatsudoki Kabushiki Kaisha Method for surface treatment of work having plural cylinders with different axial alignments
DE102017204258B4 (de) 2017-03-14 2023-08-17 Schunk Kohlenstofftechnik Gmbh Verfahren zur Herstellung eines porösen Körpers

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58161981A (ja) * 1982-03-17 1983-09-26 株式会社東芝 窒化珪素被覆セラミツクス基材の製造方法
US4515860A (en) * 1982-09-10 1985-05-07 Dart Industries Inc. Self protecting carbon bodies and method for making same
US4534842A (en) * 1983-06-15 1985-08-13 Centre National De La Recherche Scientifique (Cnrs) Process and device for producing a homogeneous large-volume plasma of high density and of low electronic temperature
JPS6333575A (ja) * 1986-07-28 1988-02-13 Nippon Soken Inc 電子サイクロトロンプラズマｃｖｄ装置
ES2006119A6 (es) * 1988-03-24 1989-04-01 Union Explosivos Rio Tinto Procedimiento de obtencion de nitruro de silicio.
DE3920450A1 (de) * 1989-06-22 1991-01-10 Schunk Kohlenstofftechnik Gmbh Gegen oxidation geschuetzte kohlenstoffkoerper und verfahren zum herstellen des oxidationsschutzes
US5254397A (en) * 1989-12-27 1993-10-19 Sumitomo Electric Industries, Ltd. Carbon fiber-reinforced composite material having a gradient carbide coating

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9318203A1 *

Also Published As

Publication number Publication date
US5489422A (en) 1996-02-06
WO1993018203A1 (fr) 1993-09-16
JPH07504713A (ja) 1995-05-25

Similar Documents

Publication Publication Date Title
US4425407A (en) CVD SiC pretreatment for carbon-carbon composites
US4472476A (en) Composite silicon carbide/silicon nitride coatings for carbon-carbon materials
US4487799A (en) Pyrolytic graphite pretreatment for carbon-carbon composites
EP0129686B1 (fr) Fibre supra-conductrice
SK11662001A3 (sk) Povlaky z karbidu volfrámu a postupy na ich výrobu
US4610896A (en) Method for repairing a multilayer coating on a carbon-carbon composite
US4560589A (en) Method for providing a coating layer of silicon carbide on substrate surface
EP0084567A4 (fr) Materiau de durete elevee.
EP0529593B1 (fr) Madrin en graphite revêtu de carbone vitreux utile pour la fabrication de silicium polycristallin
Honjo et al. Influence of carbide formation on the strength of carbon fibres on which silicon and titanium have been deposited
GB2236540A (en) Boron nitride coated fibres
KR20190042537A (ko) 식각 특성이 향상된 화학기상증착 실리콘 카바이드 벌크
EP0630425A1 (fr) Procede pour recouvrir du carbone renforce par fibres de carbone et produit ainsi obtenu
DE3534563A1 (de) Durch dispersion zaeh gemachte keramikzusammensetzungen und verfahren zu deren herstellung
CA2067145C (fr) Procede pour la formation de nitrure de bore pyrolytique exempt de fissures sur une structure et un article de carbone
CN108752012B (zh) 一种纤维表面氮化硼/氮化硅复合界面层的制备方法
Marx et al. Production and characterization of C and SiC layers on C fibres
Thamm et al. Preparation of boron nitride thin films by microwave PECVD and their analytical characterisation
Harding et al. Temperature dependence of the biaxial modulus, intrinsic stress and composition of plasma deposited silicon oxynitride films
DE19503976C1 (de) Herstellung einkristalliner dünner Schichten aus SiC
Patel et al. Studies on non-oxide coating on carbon fibers using plasma enhanced chemical vapor deposition technique
DE19506579C2 (de) Verfahren zur Herstellung von TiN-Schichten und die mit diesem Verfahren hergestellte Schicht
WO2000067311A2 (fr) Procede de production d'un support de tranches utilise en particulier dans un reacteur de depot chimique en phase vapeur haute temperature ou selon un procede de depot chimique en gaz vapeur haute temperature impliquant l'utilisation de gaz agressifs
DE4122834A1 (de) Verfahren zur beschichtung von lwl-fasern
GB2161151A (en) Composite SiC/Si3N4 coating for carbon-carbon materials

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19940905

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE DE DK FR GB IE IT LU MC NL PT SE

17Q First examination report despatched

Effective date: 19950427

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19960504