EP0185430B1 - Method for producing a metallic surface layer on a workpiece - Google Patents

Method for producing a metallic surface layer on a workpiece Download PDF

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Publication number
EP0185430B1
EP0185430B1 EP19850202093 EP85202093A EP0185430B1 EP 0185430 B1 EP0185430 B1 EP 0185430B1 EP 19850202093 EP19850202093 EP 19850202093 EP 85202093 A EP85202093 A EP 85202093A EP 0185430 B1 EP0185430 B1 EP 0185430B1
Authority
EP
European Patent Office
Prior art keywords
layer
supporting layer
mixture
workpiece
thickness
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.)
Expired
Application number
EP19850202093
Other languages
German (de)
French (fr)
Other versions
EP0185430A1 (en
Inventor
Walter Neudahm
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.)
ECG Immobilier SA
Original Assignee
Castolin SA
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 Castolin SA filed Critical Castolin SA
Publication of EP0185430A1 publication Critical patent/EP0185430A1/en
Application granted granted Critical
Publication of EP0185430B1 publication Critical patent/EP0185430B1/en
Expired legal-status Critical Current

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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
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/18—After-treatment
    • 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
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas

Definitions

  • the present invention relates to a method for producing a metallic surface layer on a workpiece and more particularly to a method for fusing a metallic surface layer applied by a conventional process.
  • the thickness of the layer that can be produced is rather limited because of the fusing process and depends on the shape, the size and the kind of the workpiece. For layers of more than 0.5 mm thickness it occurs frequently that the material of the layer sinks or runs down during the fusing which leads to very troublesome defects mainly when the fusing is effected in a furnace.
  • the thickness of the layer is limited to less than 1 mm and relatively accurate furnace temperatures, for example within ⁇ 5'C, as well as a controlled furnace working atmosphere are necessary.
  • relatively accurate furnace temperatures for example within ⁇ 5'C, as well as a controlled furnace working atmosphere are necessary.
  • the method according to the invention comprises the steps of applying a supporting layer of a ceramic oxide material at least onto the portions of the workpiece covered by a previously applied metallic surface layer, subsequently fusing said metallic layer by supplying heat thereto and removing the supporting layer after the cooling down of the workpiece.
  • the supporting layer has preferably a thickness from 0.01 to 5.0 mm. Depending on the particular case, the thickness of the supporting layer is preferably comprised between 0.2 and 3.0 or 0.2 and 0.8 mm.
  • the material of the supporting layer is preferably constituted by one or more of the following oxides Zr0 2 , Ti0 2 , MgO, CaO, A1 2 0 3 , Y 2 0 3 , Cr 2 0 3 .
  • the supporting layer is made from a mixture of Zr0 2 and 1 to 40% by weight of the total mixture, of at least one of the oxides CaO, MgO or Y 2 0 3 or from a mixture of Zr0 2 and 3 to 50% by weight of the total mixture, of AI 2 0 3 .
  • the supporting layer is made from a mixture of A1 2 0 3 and 1 to 40% by weight of the total mixture, of at least one of the oxides Ti0 2 or MgO or from a mixture of A1 2 0 3 and 1 to 30% by weight of the total mixture, of Zr0 2 .
  • the supporting layer is made from a mixture of A1 2 0 3 and 0.5 to 10% by weight of the total mixture, of Cr 2 0 3 .
  • figure 1 shows the basic arrangement of a supporting layer on a workpiece provided with a surface layer prior to the fusing thereof in upright position in a furnace
  • figure 2 shows the arrangement of a supporting layer as well as of an additional indicator layer on a workpiece for fusing with a gas torch.
  • a cylindric workpiece 1 has been provided with a surface layer 2 made for example from a self-fluxing alloy, i.e. from an alloy with additions of boron and/or silicon or phosphorus.
  • Layer 2 is applied in a conventional manner, for instance by thermal spraying using a well-known flame spraying torch supplied with a powdered alloy of the mentioned type.
  • a supporting layer of a ceramic oxide material 3 is applied onto the surface layer 2 preferably also by thermal spraying and so as to cover the surface layer as shown in the form of a kind of crucible. This allows the workpiece to be placed in a vertical position in a furnace while the temperature thereof may raise above the melting point of the self-fluxing alloy of the surface layer.
  • the oxide ceramic material of the supporting layer is selected as a function of the basic material of the workpiece and the composition of the metallic surface layer preferably in such a way that the supporting layer breaks or can easily be removed during or after the cooling-down process due to the coefficient of expansion of the ceramic oxide material.
  • the present method allows even to conduct the fusing process in a furnace by using a protecting gas or under vacuum in cases where the surface layer is composed of an alloy with a low content of boron, silicon or phosphorus, while such alloys could not be fused in a furnace by the conventional method without supporting layer.
  • Figure 2 shows an embodiment in which a workpiece 21 of rather irregular shape is provided with a metallic surface layer 22 upon which a supporting layer 23 of ceramic oxide material is applied.
  • an indicator layer 24 from the same material as the layer 22 has been sprayed over the supporting layer so as to allow to verify, during the fusing by means of a gas torch, that the fusing temperature of the surface layer has been reached.
  • the supporting layer has a thickness of less than 0.5 mm so as to avoid a high damming up of heat.
  • the thickness of the- ceramic oxide layer is chosen depending mainly upon the thickness of the surface layer to be fused and upon the shape of the workpiece onto which it is applied.
  • the thickness of the supporting layer can be made different on different portions of the workpiece depending on these criteria.
  • the composition of the supporting layer which mainly depends on the composition and thus on thefusing temperature of the metallic surface layer, determines the required porosity of the supporting layer.
  • the density of the supporting layer should be about from 80 to 95% of the theoretical density, i.e. the density of the massive material, a lesser density than the theoretical density being obtained in a known way by increasing the usual spraying distance.
  • a layer from a self-fluxing NiCrBSi-alloy has been applied by flame spraying in a thickness of 2.5 mm.
  • a ceramic supporting layer composed of AI 2 0 3 with 13% by weight Ti0 2 with respect to the total weight of the mixture of A1 2 0 3 and Ti0 2 , has been applied by flame spraying to obtain a supporting layer having a thickness of 0.5 mm.
  • the spraying distance was from 130 to 150 mm and was chosen to obtain a density of the supporting layer of about 80 to 95% of the theoretical density i.e. the density of the massive material.
  • the shaft coated as described above was then brought into a furnace in vertical position, the temperature of the furnace having been set at least 20°C above the fusing temperature of the Alloy of the surface layer.
  • the shaft was kept at this tmperature for a period of 10 minutes. After that period the shaft was removed from the furnace and cooled down. The relatively quick cooling led to a breaking of the ceramic supporting layer and falling down thereof.
  • the final metallic surface layer showed no faults such as forming of drops or running off as could be expected due to the increased temperature and the relatively long period of maintaining the same.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Coating By Spraying Or Casting (AREA)

Description

  • The present invention relates to a method for producing a metallic surface layer on a workpiece and more particularly to a method for fusing a metallic surface layer applied by a conventional process.
  • When producing metallic surface layers on metallic workpieces, in particular layers from so- called self-fluxing alloys which are fused after their application onto the metallic substrate in order to fix or bind the layer strongly to said substrate, the thickness of the layer that can be produced is rather limited because of the fusing process and depends on the shape, the size and the kind of the workpiece. For layers of more than 0.5 mm thickness it occurs frequently that the material of the layer sinks or runs down during the fusing which leads to very troublesome defects mainly when the fusing is effected in a furnace. When the mass of a workpiece exceeds 50 kg and accordingly the application of heat requires the piece to remain in the furnace for a substantial time, the thickness of the layer is limited to less than 1 mm and relatively accurate furnace temperatures, for example within ±5'C, as well as a controlled furnace working atmosphere are necessary. When workpieces have a rather irregular shape, the fusing process can often only take place under vacuum.
  • It is the main object of the invention to provide a method for producing relatively thick surface layers on workpieces allowing to prevent a sinking down or running off of the layer to be fused and in particular to provide such a method allowing to produce fused layers of more than 2 mm thickness and to fuse the same in the furnace independently of the position of the workpiece.
  • The method according to the invention comprises the steps of applying a supporting layer of a ceramic oxide material at least onto the portions of the workpiece covered by a previously applied metallic surface layer, subsequently fusing said metallic layer by supplying heat thereto and removing the supporting layer after the cooling down of the workpiece. The supporting layer has preferably a thickness from 0.01 to 5.0 mm. Depending on the particular case, the thickness of the supporting layer is preferably comprised between 0.2 and 3.0 or 0.2 and 0.8 mm.
  • The material of the supporting layer is preferably constituted by one or more of the following oxides Zr02, Ti02, MgO, CaO, A1203, Y203, Cr203. For example, the supporting layer is made from a mixture of Zr02 and 1 to 40% by weight of the total mixture, of at least one of the oxides CaO, MgO or Y203 or from a mixture of Zr02 and 3 to 50% by weight of the total mixture, of AI203.
  • Alternately, the supporting layer is made from a mixture of A1 203 and 1 to 40% by weight of the total mixture, of at least one of the oxides Ti02 or MgO or from a mixture of A1 203 and 1 to 30% by weight of the total mixture, of Zr02.
  • In still another embodiment the supporting layer is made from a mixture of A1203 and 0.5 to 10% by weight of the total mixture, of Cr203.
  • The invention, its objects and advantages will be better understood from the following description of embodiments thereof given by way of example and illustrated in the attached drawing, in which
  • figure 1 shows the basic arrangement of a supporting layer on a workpiece provided with a surface layer prior to the fusing thereof in upright position in a furnace, and figure 2 shows the arrangement of a supporting layer as well as of an additional indicator layer on a workpiece for fusing with a gas torch.
  • As shown in figure 1, a cylindric workpiece 1 has been provided with a surface layer 2 made for example from a self-fluxing alloy, i.e. from an alloy with additions of boron and/or silicon or phosphorus. Layer 2 is applied in a conventional manner, for instance by thermal spraying using a well-known flame spraying torch supplied with a powdered alloy of the mentioned type. A supporting layer of a ceramic oxide material 3 is applied onto the surface layer 2 preferably also by thermal spraying and so as to cover the surface layer as shown in the form of a kind of crucible. This allows the workpiece to be placed in a vertical position in a furnace while the temperature thereof may raise above the melting point of the self-fluxing alloy of the surface layer. A very strict maintaining and checking of the temperature of the furnace ar required in the usual processes is no longer necessary. The oxide ceramic material of the supporting layer is selected as a function of the basic material of the workpiece and the composition of the metallic surface layer preferably in such a way that the supporting layer breaks or can easily be removed during or after the cooling-down process due to the coefficient of expansion of the ceramic oxide material.
  • The present method allows even to conduct the fusing process in a furnace by using a protecting gas or under vacuum in cases where the surface layer is composed of an alloy with a low content of boron, silicon or phosphorus, while such alloys could not be fused in a furnace by the conventional method without supporting layer.
  • Figure 2 shows an embodiment in which a workpiece 21 of rather irregular shape is provided with a metallic surface layer 22 upon which a supporting layer 23 of ceramic oxide material is applied. In addition, an indicator layer 24 from the same material as the layer 22 has been sprayed over the supporting layer so as to allow to verify, during the fusing by means of a gas torch, that the fusing temperature of the surface layer has been reached. In that case, the supporting layer has a thickness of less than 0.5 mm so as to avoid a high damming up of heat.
  • Generally speaking, the thickness of the- ceramic oxide layer is chosen depending mainly upon the thickness of the surface layer to be fused and upon the shape of the workpiece onto which it is applied. The greater the thickness of the metallic surface layer and its tendency to run down due to the shape of the workpiece, the thicker the supporting layer must be made. The thickness of the supporting layer can be made different on different portions of the workpiece depending on these criteria. Furthermore, the composition of the supporting layer which mainly depends on the composition and thus on thefusing temperature of the metallic surface layer, determines the required porosity of the supporting layer. In most cases, the density of the supporting layer should be about from 80 to 95% of the theoretical density, i.e. the density of the massive material, a lesser density than the theoretical density being obtained in a known way by increasing the usual spraying distance.
  • The following example illustrates in a particular case the use of the method of the invention.
    • Example
  • Onto a shaft having a diameter of 60 mm and a length of 1000 mm, a layer from a self-fluxing NiCrBSi-alloy has been applied by flame spraying in a thickness of 2.5 mm. Subsequently a ceramic supporting layer composed of AI203 with 13% by weight Ti02 with respect to the total weight of the mixture of A1203 and Ti02, has been applied by flame spraying to obtain a supporting layer having a thickness of 0.5 mm. The spraying distance was from 130 to 150 mm and was chosen to obtain a density of the supporting layer of about 80 to 95% of the theoretical density i.e. the density of the massive material.
  • The shaft coated as described above was then brought into a furnace in vertical position, the temperature of the furnace having been set at least 20°C above the fusing temperature of the Alloy of the surface layer. The shaft was kept at this tmperature for a period of 10 minutes. After that period the shaft was removed from the furnace and cooled down. The relatively quick cooling led to a breaking of the ceramic supporting layer and falling down thereof.
  • The final metallic surface layer showed no faults such as forming of drops or running off as could be expected due to the increased temperature and the relatively long period of maintaining the same.

Claims (11)

1. A method for producing a metallic surfce layer on a workpiece comprising the steps of applying the layer on the desired portions of the workpiece, of applying a supporting layer of a ceramic oxide material at least onto the portions of the workpiece covered by said metallic layer by a process of thermal spraying in a thickness from 0.01 to 5.0 mm, of subsequently fusing the metallic layer by supplying heat thereto, and of removing the supporting layer after the cooling down of the workpiece.
2. A method according to claim 1, wherein the thickness of the supporting layer is comprised between 0.2 and 3.0 mm.
3. A method according to claim 2, wherein the thickness of the supporting layer is comprised between 0.2 and 0.8 mm.
4. A method according to claim 1, wherein the supporting layer comprises one of the oxides ZrO2, Ti02, MgO, CaO, AI203, Y203, Cr203 or a mixture of two or more of the same.
5. A method according to claim 4, wherein the supporting layer is made from a mixture of Zr02 and 1 to 40% by weight of the total mixture, of at least one of the oxides CaO, MgO or Y203.
6. A method according to claim 4, wherein the supporting layer is made from a mixture of Zr02 and 3 to 50% by weight of the total mixture, of Al2O3.
7. A method according to claim 4, wherein the supporting layer is made from a mixture of A1203 and 1 to 40% by weight of the total mixture, of at least one of the oxides Ti02 or MgO.
8. A method according to claim 4, wherein the supporting layer is made from a mixture of A1203 and 1 to 30% by weight of the total mixture, of ZrOz.
9. A method according to claim 4, wherein the supporting layer is made from a mixture of A1203 and 0.5 to 10% by weight of the total mixture, of Cr2O3.
10. A method according to claim 1, wherein the supporting layer has a thickness of not more than 0.5 mm and wherein a metallic indicator layer of between 0.01 and 1 mm thickness is applied onto the supporting layer prior to the fusing process.
11. A method according to claim 10, wherein the thickness of the indicator layer is comprised between 0.2 and 0.5 mm.
EP19850202093 1984-12-18 1985-12-17 Method for producing a metallic surface layer on a workpiece Expired EP0185430B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH598984A CH664378A5 (en) 1984-12-18 1984-12-18 METHOD FOR MELTING A METALLIC SURFACE LAYER ON A WORKPIECE.
CH5989/84 1984-12-18

Publications (2)

Publication Number Publication Date
EP0185430A1 EP0185430A1 (en) 1986-06-25
EP0185430B1 true EP0185430B1 (en) 1988-05-11

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EP19850202093 Expired EP0185430B1 (en) 1984-12-18 1985-12-17 Method for producing a metallic surface layer on a workpiece

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EP (1) EP0185430B1 (en)
CN (1) CN1005277B (en)
CH (1) CH664378A5 (en)
DE (1) DE3562630D1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01502595A (en) * 1987-03-11 1989-09-07 ナウチノ―イスレドワーチェルスキー、インスチツート、チェフノロギー、アフトモビルノイ、プロムイシュレンノスチ（ニイタフトプロム） Coating method for long and narrow workpieces
JP3204637B2 (en) * 1998-01-29 2001-09-04 トーカロ株式会社 Manufacturing method of self-fluxing alloy spray-coated member
US6648207B2 (en) * 2001-01-30 2003-11-18 Cincinnati Thermal Spray, Inc. Method for applying self-fluxing coatings to non-cylindrical ferritic objects
JP5154141B2 (en) * 2007-05-21 2013-02-27 信越化学工業株式会社 Rare earth oxide-containing thermal spray substrate and laminate
JP2009276916A (en) * 2008-05-13 2009-11-26 Sony Corp Communication device, communication method, reader/writer, and communication system
CN102452028A (en) * 2010-10-24 2012-05-16 西南交通大学 Method for repairing ceramic female die

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1159823A (en) * 1965-08-06 1969-07-30 Montedison Spa Protective Coatings
US3642519A (en) * 1969-03-21 1972-02-15 Us Air Force Method for the development of hard coat seal surfaces
US3990862A (en) * 1975-01-31 1976-11-09 The Gates Rubber Company Liquid heat exchanger interface and method
US4299865A (en) * 1979-09-06 1981-11-10 General Motors Corporation Abradable ceramic seal and method of making same
US4336276A (en) * 1980-03-30 1982-06-22 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Fully plasma-sprayed compliant backed ceramic turbine seal
CH645925A5 (en) * 1980-12-05 1984-10-31 Castolin Sa METHOD FOR PRODUCING A HOT GAS CORROSION-RESISTANT PROTECTIVE LAYER ON METAL PARTS AND HOT GAS CORROSION-RESISTANT PROTECTIVE LAYER ON METAL PARTS.
US4481237A (en) * 1981-12-14 1984-11-06 United Technologies Corporation Method of applying ceramic coatings on a metallic substrate
US4485151A (en) * 1982-05-06 1984-11-27 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Thermal barrier coating system

Also Published As

Publication number Publication date
CH664378A5 (en) 1988-02-29
EP0185430A1 (en) 1986-06-25
CN1005277B (en) 1989-09-27
CN85108900A (en) 1986-06-10
DE3562630D1 (en) 1988-06-16

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