EP0409687A1 - Verfahren zum Aufsilizieren von metallischen Gegendstand durch chemische Abscheidung aus der Dampfphase - Google Patents

Verfahren zum Aufsilizieren von metallischen Gegendstand durch chemische Abscheidung aus der Dampfphase Download PDF

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Publication number
EP0409687A1
EP0409687A1 EP90401931A EP90401931A EP0409687A1 EP 0409687 A1 EP0409687 A1 EP 0409687A1 EP 90401931 A EP90401931 A EP 90401931A EP 90401931 A EP90401931 A EP 90401931A EP 0409687 A1 EP0409687 A1 EP 0409687A1
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EP
European Patent Office
Prior art keywords
temperature
steel
silicon
silane
siliciding
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.)
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Application number
EP90401931A
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English (en)
French (fr)
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EP0409687B1 (de
Inventor
Pierre Jalby
Michel Gastiger
Thierry Jacquin
Eric Gosse
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.)
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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    • 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
    • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
    • C23C10/06—Solid state diffusion of only metal elements or silicon into metallic material surfaces using gases
    • C23C10/08—Solid state diffusion of only metal elements or silicon into metallic material surfaces using gases only one element being diffused

Definitions

  • the present invention relates to a method for improving the surface properties of metal parts by siliciding by means of chemical gas deposition.
  • the invention relates, more particularly, to a method of siliciding by chemical gas deposition for improving the surface properties, in particular the hardness and the corrosion resistance of steel parts.
  • the metal parts need a surface treatment to meet the technical and economic requirements of their environment of use.
  • Surface treatment makes it possible to improve the surface properties of metal parts, either by modifying the composition of a surface layer of these parts, or by depositing a layer of another material on the surface of these parts. .
  • the present invention relates more particularly to the chemical gas deposition method (sometimes called “Chemical Vapor Deposition” or CVD), in particular for the siliciding of steel parts.
  • CVD chemical gas deposition
  • the chemical gas deposition method for metal siliciding has many advantages. It makes it possible in particular to obtain a uniform deposit layer on the surface of the parts to be treated with relatively low treatment temperatures, and does not require a high vacuum.
  • the other methods of siliciding known in the art have on the contrary a certain number of drawbacks, such as the high cost of production (ion implantation), the difficulties of implementation (electrolysis, ion implantation), the non-uniformity of the deposit ( ion implantation, projection of plasma) or too great thicknesses of deposition layers (projection of plasma, sintering), etc.
  • AIR PRODUCTS is the siliciding of metals by chemical deposition in the gas phase using silane (SiH4) in a hydrogen flow at temperatures in the region of 600 to 700 °. vs.
  • SiH4 silane
  • the document describes a process of diffusion of silicon in the metal obtained by making a pretreatment of the substrates under a hydrogen atmosphere, controlling and minimizing the rate of water vapor in the oven.
  • the silicon diffusion layer obtained improves the anti-corrosion properties at high temperature and inhibits the formation of coke during cracking operations of hydrocarbons.
  • the object of the present invention is therefore to produce, under special conditions, a silicided layer of metals by chemical deposition in the gaseous phase of silane (Si n H 2n + 2 ) to improve the surface properties, in particular the mechanical properties of the parts. processed.
  • the method of the invention makes it possible in particular to improve the surface properties of steel parts, in particular for their surface hardness.
  • a steel part is prepared in the clean state; then the part is heated in an oven to a predetermined temperature T0 between 800 ° and 1100 ° C; then a gaseous mixture containing an inert gas and a silane Si n H 2n + 2 is injected into the furnace where the steel part is kept at temperature T0, so as to form a diffusion layer containing from 10% to 40% of silicon in atomic percentage on the surface of the steel part.
  • the volume proportion of silane in the gas mixture is preferably less than 10%.
  • the siliciding temperature T0 is advantageously greater than 850 ° C.
  • the part after having been exposed to the temperature T0, the part is preferably cooled to around 850 ° C., then quenched for example in an oil at room temperature.
  • We can then perform a tempering of the part at a temperature of on the order of 550 ° to 600 ° C for about 30 to 60 minutes.
  • the stages after siliciding can be modified according to the type of steel constituting the part to be treated.
  • the steel part is maintained at the siliciding temperature T0 for a period of between 0.5 and 40 hours depending on the value of T0.
  • the flow rate of the gas mixture per unit volume of the oven can vary between 1 and 10.
  • the total pressure of the gas mixture is preferably less than 1000 Pascals.
  • the volume proportion of silane in the gas mixture is between 10 ppm and 5%, and is strongly influenced by the siliciding temperature T0.
  • this proportion can be chosen between 0.1% and 5%.
  • the gas mixture injected, during the step of maintaining the temperature T0 at which the siliciding of the part takes place preferably contains no other gaseous constituents than silane and argon.
  • Helium can also be used as the sole diluent for silane.
  • the furnace is preferably filled with an inert gas, in particular argon. It is also possible to inject a small volume percentage of hydrogen of less than 20% in this inert gas.
  • the total gas pressure is preferably less than 1000 Pascals, but can also reach atmospheric pressure.
  • the method of the invention is particularly suitable for treating carbon steel parts having a carbon content of less than 0.5%.
  • the improvements concerning in particular the hardness and the corrosion resistance of the parts are particularly remarkable for this type of steel.
  • the pressure in the oven during the heating of the room can go up to atmospheric pressure.
  • this pressure is controlled below 1000 Pascals.
  • the total flow rate of the gas or gases per unit volume of the oven during the heating phase is preferably chosen between 1 and 10.
  • the part is maintained at the temperature T0 and a gas mixture consisting of silane is injected having a volume proportion of between 100 ppm and 1%, preferably between 0.5 and 1%, diluted in a inert gas, for example argon.
  • the siliciding time at temperature T0 can advantageously be controlled between 2 and 10 hours.
  • the quality of the silicon diffusion layer obtained on the surface of the part after siliciding depends essentially on the composition and the surface condition of the substrate, and on the kinetics of siliciding, the main parameters of which are the temperature of the part. and the amount of silane present on the surface of the part.
  • the gas mixture containing the silane is therefore introduced inside the furnace, so as to bring about the contact between the gaseous atmosphere and the surface of the part in steel. It is then estimated that the following phenomena occur: - adsorption of gaseous species, including silane, on the surface of the part; - chemical reaction on the surface of the part consisting in part of the decomposition of the silane into silicon and hydrogen; - diffusion of silicon in the steel part forming a silicon diffusion layer; - desorption and diffusion of the volatile products formed.
  • the hydrogen released during the decomposition of silane allows a reduction of the oxygen possibly present in the environment thus avoiding the possibility of formation of an oxide layer on the surface of the part to be treat during siliciding.
  • the total pressure of the gas mixture during siliciding is preferably kept below 500 Pascals.
  • monosilane (SiH4) or disilane (Si2H6) is used for siliciding according to the process of the invention.
  • a piece of carbon steel type 42 CD 4 (0.41% C; 0.31% Si; 0.64% Mn; 0.94% Cr, 0.21% Mo) is formed.
  • the surface of the part is degreased and deoxidized in an ultrasonic bath with acids and solvents.
  • the part is then placed in a horizontal oven with hot walls which is then heated to 1000 ° C in argon having a pressure of less than 1000 Pascals.
  • the silane (SiH4) diluted in argon (Ar) is injected into the oven maintained at a pressure of approximately 300 Pascals and at a temperature of 1000 ° C.
  • the volume proportion of silane is approximately 0.5%.
  • the total flow rate of the silane / argon mixture is of the order of 0.4 dm3 / minute.
  • the reaction is allowed to proceed for 2 hours, then the temperature is lowered to 850 ° C, maintained for about 30 minutes, the part is quenched and tempered at 550 ° C for 1 hour.
  • results obtained show a significant increase in surface hardness which varies from 330 HV (in VICKERS hardness) before treatment to around 500 HV after treatment, hardness tests being carried out with 200 g of filler.
  • CD 4 carbon steel samples are prepared in the form of pellets with a thickness of 2 mm and a diameter of 10 mm.
  • the samples are cleaned in a liquid medium under ultrasound using Branson (registered trademark) product, so as to degrease and deoxidize the surface of the samples.
  • Branson registered trademark
  • the samples are then placed in a tubular oven which is then heated to the siliciding temperature T0 above 850 ° C., under argon at 500 Pascals.
  • T0 the temperature at which the samples are maintained at this temperature while a gas mixture consisting of 2.5% K2, 0.5% SiH4, 9% He and 88% Ar is injected into the oven. total and the total pressure of the gas mixture are respectively 1 dm3 / minute and 300 Pascals.
  • the siliciding time is equal to 2 hours.
  • the temperature is then lowered to 850 °, then the samples are tempered at 550 ° for half an hour.
  • the samples thus treated are then analyzed using the usual observation devices, such as the scanning electron microscope, roughness meter, the X-ray analyzer, the AUGER spectroscope and the microdurometer.
  • the hardness decreases rapidly from the surface of the silicided layer to a depth of approximately 100 ⁇ m inside this layer. Then the hardness becomes almost constant when the analyzed depth exceeds 100 ⁇ m.
  • the hardness decreases relatively slowly from the surface of the layer to around 250 ⁇ m. Then the hardness decreases suddenly between 250 ⁇ m and 300 ⁇ m deep to reach a plateau from 300 ⁇ m deep.
  • the siliciding depth is greater when the siliciding temperature T0 is greater, which can be interpreted by the increasing speed of diffusion of the species as a function of the temperature. It can be considered that the siliciding depth corresponds to the thickness of the silicon diffusion layer in the iron.
  • FIG. 2 shows the profile of the hardness at 25 ⁇ m deep in the silicon diffusion layer as a function of the atomic percentage of silicon at this depth.
  • FIG. 1 shows the profile of the hardness at 25 ⁇ m deep in the silicon diffusion layer as a function of the atomic percentage of silicon at this depth.
  • the concentration of silicon is greater than 40%, the silicon diffusion layer certainly has a very high hardness but becomes brittle and the layer cracks.
  • the method of the invention aims to obtain a percentage of silicon in the diffusion layer of between 10% and 40 atomic%. Preferably, this percentage varies between 15% and 30%.
  • the present invention is not limited to the only method of chemical deposition in the gas phase by low pressure thermal heating as described above.
  • Other derived methods such as chemical pressure gas deposition atmospheric or plasma or laser assisted, can be used.
  • Other heating means for example induction heating of the room, can be used.
  • chemical gas deposition by low pressure thermal heating is more easily adaptable for use on an industrial scale.
  • the process of the invention may undergo slight modifications to allow the improvement of other surface properties of metals, in particular their resistance to abrasion, the obtaining of a layer of high magnetic permeability, the creation of an interface. silicided on the metal allowing easy attachment of ceramic parts or deposits, obtaining an inert layer for certain chemical reactions.
  • the process could be further improved by multilayer deposits having complementary properties, such as for example an anti-corrosion silicide layer and a lubricating iron sulfide layer. It is also possible to produce, using the process of the invention, composite layers of silicide and iron nitride to increase the hardness or to adapt the composition of the surface to promote ceramic-metal adhesion and for the case of silicon-based ceramics.
  • the metal parts obtained by the present process can be used in particular in the mechanical industries and the steel transformation industries for the improvement of surface properties with respect to corrosion, hardness, resistance to abrasion, passivation, adhesion, magnetism, etc.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Vapour Deposition (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
EP19900401931 1989-07-19 1990-07-04 Verfahren zum Aufsilizieren von metallischen Gegendstand durch chemische Abscheidung aus der Dampfphase Expired - Lifetime EP0409687B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8909697 1989-07-19
FR8909697A FR2649995B1 (fr) 1989-07-19 1989-07-19 Procede de siliciuration d'aciers par depot chimique en phase gazeuse

Publications (2)

Publication Number Publication Date
EP0409687A1 true EP0409687A1 (de) 1991-01-23
EP0409687B1 EP0409687B1 (de) 1996-11-06

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EP19900401931 Expired - Lifetime EP0409687B1 (de) 1989-07-19 1990-07-04 Verfahren zum Aufsilizieren von metallischen Gegendstand durch chemische Abscheidung aus der Dampfphase

Country Status (5)

Country Link
EP (1) EP0409687B1 (de)
JP (1) JPH03138350A (de)
CA (1) CA2021305A1 (de)
DE (1) DE69029064T2 (de)
FR (1) FR2649995B1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0509907A1 (de) * 1991-04-17 1992-10-21 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude CVD-Verfahren zum Herstellen einer Siliziumdiffusionsschicht und/oder Überzug auf der Oberfläche eines Metallsubstrates

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4560077B2 (ja) 2007-11-12 2010-10-13 トヨタ自動車株式会社 磁心用粉末および磁心用粉末の製造方法
DE102017110221A1 (de) * 2017-05-11 2018-11-15 Gottfried Wilhelm Leibniz Universität Hannover Verfahren zur Wärmebehandlung eines Bauteils sowie Anlage dafür

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1042076A (fr) * 1950-09-15 1953-10-28 Union Chimique Belge Sa Procédé pour rendre la surface de l'acier dure et résistant à la corrosion
DE1945298A1 (de) * 1968-09-13 1970-03-19 Allegheny Ludlum Steel Verfahren und Vorrichtung zum Aufsilizieren
FR2587730A1 (fr) * 1985-09-23 1987-03-27 Rhone Poulenc Rech Procede de siliciuration d'un substrat metallique ferreux et substrat metallique ferreux silicie
EP0226130A2 (de) * 1985-12-11 1987-06-24 Air Products And Chemicals, Inc. Verfahren zum Herstellen einer Siliziumdiffusionsschicht auf metallischen Werkstücken

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1108158A (fr) * 1953-07-03 1956-01-10 Procédé pour <l'ennoblissement> de la surface de métaux, en particulier du fer etde l'acier
GB1072932A (en) * 1963-11-01 1967-06-21 Berghaus Elektrophysik Anst Method of and apparatus for surface hardening bodies by gaseous treatment
GB1128609A (en) * 1964-12-31 1968-09-25 Allegheny Ludlum Steel Improvements in or relating to silicon steel
JPS58141376A (ja) * 1982-02-16 1983-08-22 Seiko Epson Corp プラズマセメンテ−シヨン

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1042076A (fr) * 1950-09-15 1953-10-28 Union Chimique Belge Sa Procédé pour rendre la surface de l'acier dure et résistant à la corrosion
DE1945298A1 (de) * 1968-09-13 1970-03-19 Allegheny Ludlum Steel Verfahren und Vorrichtung zum Aufsilizieren
FR2587730A1 (fr) * 1985-09-23 1987-03-27 Rhone Poulenc Rech Procede de siliciuration d'un substrat metallique ferreux et substrat metallique ferreux silicie
EP0226130A2 (de) * 1985-12-11 1987-06-24 Air Products And Chemicals, Inc. Verfahren zum Herstellen einer Siliziumdiffusionsschicht auf metallischen Werkstücken

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
MATERIALS CHEMISTRY, vol. 5, 1980, pages 147-164, Cenfor S.R.L., IT; A. ABBA et al.: "Protection du fer contre l'oxydation par siliciuration superficielle" *
SURFACE AND COATINGS TECHNOLOGY, no. 39/40, 1989, pages 43-51, Elsevier, Lausanne, CH; A.L. CABRERA et al.: "Formation of silicon diffusion coatings on ferrous alloys from their reaction with silane" *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0509907A1 (de) * 1991-04-17 1992-10-21 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude CVD-Verfahren zum Herstellen einer Siliziumdiffusionsschicht und/oder Überzug auf der Oberfläche eines Metallsubstrates

Also Published As

Publication number Publication date
JPH03138350A (ja) 1991-06-12
DE69029064D1 (de) 1996-12-12
CA2021305A1 (fr) 1991-01-20
FR2649995B1 (fr) 1993-08-13
DE69029064T2 (de) 1997-06-05
EP0409687B1 (de) 1996-11-06
FR2649995A1 (fr) 1991-01-25

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