GB2446056A - Removing coatings using a dry ice blast - Google Patents
Removing coatings using a dry ice blast Download PDFInfo
- Publication number
- GB2446056A GB2446056A GB0801245A GB0801245A GB2446056A GB 2446056 A GB2446056 A GB 2446056A GB 0801245 A GB0801245 A GB 0801245A GB 0801245 A GB0801245 A GB 0801245A GB 2446056 A GB2446056 A GB 2446056A
- Authority
- GB
- United Kingdom
- Prior art keywords
- protective coating
- coating
- component
- dry ice
- substrate
- 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.)
- Granted
Links
- 238000000576 coating method Methods 0.000 title claims abstract description 54
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 title claims abstract description 48
- 235000011089 carbon dioxide Nutrition 0.000 title claims abstract description 32
- 239000011253 protective coating Substances 0.000 claims abstract description 66
- 238000000034 method Methods 0.000 claims abstract description 57
- 239000011248 coating agent Substances 0.000 claims abstract description 48
- 238000005422 blasting Methods 0.000 claims abstract description 17
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 8
- 239000000919 ceramic Substances 0.000 claims abstract description 8
- 239000010959 steel Substances 0.000 claims abstract description 8
- 238000005480 shot peening Methods 0.000 claims abstract description 7
- 238000002485 combustion reaction Methods 0.000 claims abstract description 6
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 claims abstract description 4
- 229910001928 zirconium oxide Inorganic materials 0.000 claims abstract description 4
- 230000008569 process Effects 0.000 claims description 24
- 239000000758 substrate Substances 0.000 claims description 24
- 239000012720 thermal barrier coating Substances 0.000 claims description 15
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 8
- 239000001569 carbon dioxide Substances 0.000 claims description 8
- 229910045601 alloy Inorganic materials 0.000 claims description 7
- 239000000956 alloy Substances 0.000 claims description 7
- 230000015572 biosynthetic process Effects 0.000 claims description 3
- 230000001681 protective effect Effects 0.000 claims description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 abstract description 7
- 238000010438 heat treatment Methods 0.000 abstract description 6
- 229910000990 Ni alloy Inorganic materials 0.000 abstract description 2
- 239000000654 additive Substances 0.000 abstract description 2
- 229910000531 Co alloy Inorganic materials 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 15
- 239000007789 gas Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000007669 thermal treatment Methods 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000032798 delamination Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 230000008646 thermal stress Effects 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000005524 ceramic coating Methods 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 238000000859 sublimation Methods 0.000 description 1
- 230000008022 sublimation Effects 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000007751 thermal spraying Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
- B24C1/003—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods using material which dissolves or changes phase after the treatment, e.g. ice, CO2
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
- B24C1/08—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods for polishing surfaces, e.g. smoothing a surface by making use of liquid-borne abrasives
- B24C1/086—Descaling; Removing coating films
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
- B24C1/10—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods for compacting surfaces, e.g. shot-peening
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/005—Repairing methods or devices
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/12—Blades
- F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
- F01D5/286—Particular treatment of blades, e.g. to increase durability or resistance against corrosion or erosion
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/12—Blades
- F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
- F01D5/288—Protective coatings for blades
Abstract
A method of removing a protective coating 12 from a metallic component 11 by first pre-damaging the coating 12 and then blasting the damaged coating 12 with dry ice. Pre-damaging of the protective coating 12 occurs by generating cracks therein by heating either a localized region of the component or the complete component by oven, burner, plasma jet or laser or by shot peening using 0.05-5 mm diameter steel balls in compressed air. The component may be a part of an internal combustion engine, a rotor blade or a stator blade made from a nickel or cobalt-based alloy, with the protective coating being formed of a ceramic such as yttrium-stabilised zirconium oxide, a La-oxide or ZrO with additives. A thermally grown oxide coating 13 and/or a bonding layer 22 may also be present between the component 11 and the protective coating 12.
Description
DESCRIPTION
METHOD FOR TREATING A THERMALLY LOADED COMPONENT
TECHNICAL FIELD
The present invention relates to the field of thermal machines. it refers to a method for treating a thermally loaded component according to the preamble of claim 1.
BACKGROUND OF THE INVENTION
Thermally loaded components of gas turbines, such as stator blades or rotor blades or elements of the associated combustion chamber, which on account of the high operating temperatures are produced from Ni-based alloys, are frequently coated on the surface with a ceramic thermal barrier coating (TBC). When applying these thermal barrier coatings, local defects can occur, which are not acceptable with regard to later application, or which have to be removed for other reasons. If such local defects occur, the whole thermal barrier coating, inclusive of the bonding layer which lies beneath it, currently has to be removed by means of a chemical and/or combined chemical/mechanical removal process. This chemical process is very burdensome and costly, and requires greater finish-machining. Also, it is not possible to selectively remove only areas of the protective coating in order to finish used components, for example, for renewed application.
It would be desirable, therefore, to have available a less costly and locally applicable process by which only the protective coating or thermal barrier coating of such a component can be purposefully removed.
From the prior art, different methods for local removal of ceramic coatings are already known (see, for example, the publications TJS-A1-2005/0126001, US-Al- 2004/0244910, WO-A1-02/103088, WO-A1-2005/083158, DE- Al-lO 2004 009 757, US-A1--2004/0115447, US-Al-2004/0256504, US-A1-2003/0100242 and DE-B4-103 60 063).
Other methods for local repair of coating systems are known from the publications US-A1-2002/0164417, DE-T2- 601, 03 612, US-A1--2003/0101687, EP-A1-1 304 446, EP-A1-0 808 913 and US-B1-6, 235, 352.
The complete removal of thermal barrier coatings by means of chemical methods alone, or in combination with other methods, have been handled in a different way in the publications DE-Al-lO 2004 049 825, US-Al-2001/0009246, US-A1-2001/0009247 and EP-B1-1 076 114.
Furthermore, it is known (Fr. -W. Bach et al., "Abtragen von thermisch gespritzten Schichten mit dem Trockeneis-Laserstrahl", GTS-Strahl Vol. 14, Sept.
2004; Fr. -. Bach et al., "Dry ice blasting and water jet processes for the removal of thermal sprayed coatings", Conf. Proc. ITSC 2005, Basle, p. 1542 -1548 (2005)) to remove protective coatings, such as thermal barrier coatings, which are on components, by means of a dry ice blasting process.
With this type of coating removal, however, the complete removal of the coating on the one hand, and the least possible influencing of the metallic coatings (either the metal substrate as such, or the metallic bonding layer or adhesion mediating coating which lies above it) which lies beneath the coating which is to be removed on the other hand, is problematic. Previous processes suffer from low efficiency or very long treatment durations.
SUMMARY OF THE INVENTION
It is the object of the invention to disclose a method for removing such protective coatings or thermal barrier coatings, which utilize the advantages of the dry ice blasting process without being encumbered with its disadvantages.
The object is achieved by the entirety of the features of claim 1. A two-stage treatment process, in which before the application of the dry ice blasting process the protective coating is first of all purposefully predamaged in a first step, is essential for the invention. By means of the purposeful predamaging of the coating which is to be removed, this can be more effectively, i.e. in shorter time, completely removed in the subsequent dry ice blasting process and without greater influence upon possible metal coatings which lie beneath it.
A development of the invention is characterized in that cracks are created in the protective coating for predarnaging the protective coating, or the component is locally heated, or heated as a whole, to a temperature far above room temperature.
For this purpose, the component can be locally heated, or heated as a whole, by means of a burner, a plasma jet or a laser jet. Furthermore, heating of the whole component, for example in an oven, is possible. If the component has a substrate consisting of an Ni-based or Co-based alloy, it can be heated up as a whole to a temperature of up to 600 C. Alternatively or additionally to heating up, the protective coating, however, can also be shot-peened for creating cracks or creating predamage, wherein steel balls, with a diameter of between 0.5 and 5 mm, are preferably used, and for blast formation the steel balls are introduced into a high-speed gas flow, especially consisting of compressed air. The use of ceramic balls is also conceivable.
During the subsequent dry ice blasting, dry ice grains consisting of carbon dioxide at a temperature of about -78 C are preferably used. In particular, the dry ice grains consist of compressed carbon dioxide snow and have a diameter of between 1 and 3.5 mm and a length of between 2 and 10 mm.
It is especially favorable if the dry ice grains are accelerated to speeds of about 300 rn/s in a compressed air flow, before striking the predamaged protective coating. -According to another development of the invention, there is a thermally grown oxide coating directly beneath the protective coating, and the thermally grown oxide coating is removed together with the protective coating.
A bonding layer can be provided between the substrate and protective coating; the protective coating can then be removed down to the bonding layer.
The component to be treated preferably has a substrate consisting of an Ni-based alloy, and the protective coating is a ceramic thermal barrier coating, especially consisting of yttrium-stabilized zirconium oxide.
The component can preferably be a stator blade or rotor blade of a gas turbine, or a protective segment of the combustion chamber of an internal combustion engine.
BRIEF DESCRIPTION OF THE FIGURES
The invention is to be subsequently explained in more detail with reference to exemplary embodiments in conjunction with the drawing. In the drawing: Fig. 1 shows in a plurality of sub-figures 1(a) to 1(f) different steps during the removal of a protective coating, which is directly applied to a substrate, according to an exemplary embodiment of the method according to the invention, wherein on the left, a (new) component without thermally grown oxide coating, and on the right, a (used) component with thermally grown oxide coating, is shown in each case; and Fig. 2 shows in a plurality of sub-figures 2(a) to 2(f) different steps during the removal of a protective coating, which is applied to a substrate via an adhesion mediating intermediate coating (bonding layer), according to another exemplary embodiment of the method according to the invention, wherein on the left, a (new) component without thermally grown oxide coating, and on the right, a (used or preoxidized) component with thermally grown oxide coating, is shown in each case.
WAYS OF IMPLEMENTING THE INVENTION
The present invention refers to a method for removing a brittle coating system (protective coating 12 in Fig. 1(a) or Fig. 2(a)) from a metallic surface (a substrate 11 in Fig. 1(a) or 2(a)). The coating system which is to be removed is typically a ceramic system, i.e. a thermal barrier coating such as yttrium-stabilized zirconium oxide (Zr027%Y203 or the like) or comprises a coating consisting of the system La-oxide, or ZrO with additives from the range of rare earths (Er, Yb) and P and Gd. The thermal barrier coating can be applied by means of thermal spraying processes, which use powder or solutions/suspensions as a carrier of the coating material, and also can also be applied by means of other physical processes like EB-PVD.
In the case of used components, which were already subjected to a longer thermal loading in the presence of oxygen, a thermally grown oxide coating (13 in Fig. 1(a) or 2(a), right-hand column), may have been formed beneath the upper protective coating 12. Such an oxide coating (TGO) can also be established by means of a purposeful preoxidation. This thermally grown oxide coating 13 can also be removed within the scope of the removal process according to the invention. The removing of the coating 12, or coatings 12 and 13, is carried out from a metallic surface of a substrate 11 (Fig. 1) which lies beneath it, which, if the component is a stator blade or rotor blade of a gas turbine, customarily consists of an Ni-based or Co-based alloy, without the surface of the substrate 11 being damaged.
The coating system which is on the substrate 11, however, can also comprise at least one intermediate coating in the form of a bonding layer 22 (Fig. 2) beneath the protective coating 12. In this case, the upper protective coating 12 is removed by the method according to the invention without the bonding layer 22 which lies beneath it being damaged.
The advantage of the method according to the invention -35 is that the brittle protective coating 12 can be completely removed without it happening to the metallic coating which lies beneath it, whether it be the substrate 11 itself (Fig. 1) or an interposed bonding layer 22 (Fig. 2). That means that after removing the protective coating 12, the metallic surface which lies beneath it is in an activated and cleaned state, wherein the surface roughness is comparable to that before removing the protective coating 12. In this way, the metallic surface can be recoated with a bonding adhesive which is comparable to the original bonding adhesive of the protective coating 12.
A two-stage process is essential for the method according to the invention: in a first step, the coating which is to be removed is predamaged by means of a suitable pretreatment. The predamaging achieves the effect of the coating then being able to be more easily and completely removed in a second step. The predamaging of the protective coating can be carried out either by means of a heat treatment of the component, or by means of a mechanical action on the coating by means of a shot-peening process, or by means of a combination of the two methods. For the actual removal of the (predamaged) coating, a dry ice blasting process is used, in which a jet of greatly accelerated dry ice grains is directed onto the coating surface, and there, acts on the one hand mechanically and on the other hand thermally (by means of shock cooling) on the coating.
The two-stage process is necessary because just by the dry ice blasting process, i.e. without predamaging the coating, residues of the coating remain on the component which then hinders finishing of the component. The predamaging of the coating, therefore, effectively prevents coating residues remaining on the component surface and increases the efficiency or reduces the process duration.
According to Fig. 1(a), the method starts from a new component 10 which is provided with a protective coating 12, especially in the form of a ceramic thermal barrier coating (TBC), on a metallic substrate 11 (left-hand side of Fig. 1(a)). However, it can also start from a component 10' which in use has already been subjected to a thermal loading in the presence of oxygen, and, therefore, a thermally grown oxide coating (TGO) 13 has formed on the interface between substrate 11 and the protective coating 12 (right-hand side of Fig. 1(a)).
For predamaging the protective coating 12, the components 10, 10' are now subjected to a thermal treatment at temperatures T far above room temperature TR (Fig. 1(b)), and/or are mechanically machined by means of a shot-peening process (Fig. 1(c)).
The thermal treatment (for the component 10, 10' as a whole) can be undertaken in an oven, or by means of local heating with a burner, a plasma jet or a laser jet. If the substrate 11 is produced from an Ni-based alloy, the thermal treatment can be carried out at temperatures of up to 600 C. On account of the different thermal expansion coefficients of the substrate material and of the protective coating material, according to Fig. 1(d) the formation of cracks 17 in the protective coating 12, and therefore an effective predamaging of the protective coating 12, occurs. The heating up leads to an increase of the temperature difference between component and dry ice, which leads to an increased removal rate.
For implementing the shot-peening process, according to Fig. 1(c) steel balls (or ceramic balls) 16, with a diameter of between 0.5 and 5 nun, are introduced into a high-speed gas jet (for example compressed air) and are shot through the nozzle 15 of a corresponding shot-peening device 14 onto the surface of the protective coating 12 which is to be removed. The impact of the balls 16 on the surface creates cracks 17 and partially even creates a delamination of the protective coating 12, and so leads to an effective predamaging.
After the predamaging of the protective coating 12 which is created in this way in the first step, the predamaged protective coating 12 is completely removed in the second step (Fig. 1(e)) by using a dry ice blasting device 18. The dry ice blasting process uses dry ice grains 21 consisting of solid carbon dioxide at temperatures of about -780 C. The dry ice grains consist of compressed carbon dioxide snow and have a diameter of between 1 and 3.5 mm and a length of between 2 and 10 nun. The dry ice grains 21 are accelerated in a compressed air flow to speeds of about 300 rn/s and are then shot through a nozzle 19 onto the surface of the predamaged protective coating 12.
Typical pressures of the compressed air which is used are between 0.1 and 1.6 MPa in this case. Depending upon application, round or flat nozzles 19 can be used in this case.
The dry ice blasting process acts upon the protective coating 12 by means of a combination of mechanical and thermal mechanisms: the kinetic energy of the blast medium, on account of shock waves on the interface between protective coating 12 and substrate 11 creates further cracks and removes particles of the protective coating 12 which are already blasted off, or which have only poor adhesion to the coating.
During impact of the dry ice grains 21, some of the kinetic and thermal energy is converted into sublimation energy. The volume of the solid carbon dioxide grows by a factor of up to 700. Large pressure gradients on the surface of the protective coating 12 result from it. The gaseous carbon dioxide can be drawn off together with the blasted off particles of the -10 -coating and, after filtering, can be let out into the environment without producing further waste.
A very thin surface layer of the protective coating 12 is cooled down at high cooling speed to -50 C, wherein thermal stresses are created, which, in the case of large differences in the thermal expansion coefficients between substrate 11 and protective coating 12, are particularly large. These thermal stresses also lead to cracks 17 in the protective coating 12, weaken these further, and promote delamination. Since dry ice, comparable with gypsum, is rather soft, there is practically no abrasive effect. Consequently, the protective coating 12 can be removed without the metallic coating which lies beneath it being damaged, even if it consists of mild steel or high-grade steel, nickel alloys or even aluminum alloys. -By means of the dry ice blasting process, the protective coating is completely removed in the case of a new component 10, and the thermally grown oxide coating 13 (Fig. 1(f) which lies beneath it is additionally also removed in the case of an already used component 10' With thermally loaded components, a metallic bonding layer 22 (for example MCrA1Y), or an aluminum layer or PtA1 layer (Fig. 2(a)), in most cases is arranged between the protective coating 12 and the substrate 11 for better bonding adhesion of the protective coating 12. If it concerns a new component 20, the protective coating 12 and the bonding layer directly adjoin each other (left-hand section of Fig. 2(a)). If the component 20' is used, a thermally grown oxide coating 13 (right-hand side of Fig. 2(a)) has been formed in turn on the interface between the two coatings.
With this type of coating, exactly the same procedure -11 -is also followed as with components without a bonding layer. Figs. 2(a) to 2(f), therefore, show the same steps and process parameters similar to Figs. 1(a) to 1(f). In the end (Fig.2(f)), the protective coating 12 and a possible thermally grown oxide coating 13 are completely removed from the component 20, 20' so that the bonding layer 22 which lies beneath it is extensively revealed.
-12 -
LIST OF DESIGNATIONS
10, 10' Component (especially thermally loaded) 11 Substrate 12 Protective coating (TBC) 13 Thermally grown oxide coating (TGO) 14 Shot-peening device Nozzle 16 Ball (for example consisting of steel) 17 Crack 18 Dry ice blasting device 19 Nozzle 20, 20' Component (especially thermally loaded) 21 Dry ice grain 22 Bonding layer T Temperature Room temperature
Claims (15)
- CLAIMS: 1. A method for treating a thermally loaded component whichcomprises a metallic substrate, which on the outer side is coated with a protective coating, in which method the protective coating is removed from the substrate by using a dry ice blasting process, characterized in that before the application of the dry ice blasting process the protective coating is first of all predamaged in a first step in such a way that the predamaging leads to an increase of the efficiency of the removal process.
- 2. A method as claimed in claim 1, characterized in that cracks are created in the protective coating for predamaging the protective coating.
- 3. A method as claimed in claim 1 or 2, characterized in that the component is locally heated, or heated as a whole, to a temperature (T) far above room temperature (TR).
- 4. A method as claimed in claim 3, characterized in that the component is locally heated, or heated as a whole, by means of a burner, a plasma jet or a laser jet.
- 5. A method as claimed in claim 3, characterized in that the component has a substrate consisting of an Ni-based or Co-based alloy, and is heated up as whole to a temperature (T) of up to 600 C.
- 6. A method as claimed in one of claims 2 to 5, characterized in that the protective coating is shot-peened for creating the cracks.
- 7. A method as claimed in claim 6, characterized in that steel balls, with a diameter of between 0.5 and 5 mm, are used for the shot-peening, and for blast formation the steel balls are introduced into a high-speed gas flow, especially consisting of compressed air.
- 8. A method as claimed in one of claims 1 to 7, characterized in that dry ice grains consisting of carbon dioxide at a temperature of about -78 C, are used for dry ice blasting.
- 9. A method as claimed in claims 8, characterized in that the dry ice grains consist of compressed carbon dioxide snow and have a diameter of between 1 and 3.5 mm and a length of between 2 and 10 mm.
- 10. A method as claimed in claim 9, characterized in that the dry ice grains are accelerated in a compressed air flow to speeds of about 300 rn/s before striking the predarnaged protective coating.
- 11. A method as claimed in one of claims 1 to 10, characterized in that there is a thermally grown oxide coating directly beneath the protective coating, and in that the thermally grown oxide coating is removed together with the protective coating.
- 12. A method as claimed in one of claims 1 to 11, characterized in that a bonding layer is provided between the substrate and the protective coating, and in that the protective coating is removed down to the bonding layer.
- 13. A method as claimed in one of claims 1 to 12, characterized in that the component has a substrate consisting of an Ni-based or a Co-based alloy, and in that the protective coating is a ceramic thermal barrier coating, especially consisting of yttrium-stabilized zirconium oxide.
- 14. A method as claimed in claim 13, characterized in that the component is a stator blade or rotor blade of a gas turbine.
- 15. A method as claimed in claim 13, characterized in that the component is a burner component, especially a protective segment of the combustion chamber of an internal combustion engine.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH1032007 | 2007-01-23 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0801245D0 GB0801245D0 (en) | 2008-02-27 |
| GB2446056A true GB2446056A (en) | 2008-07-30 |
| GB2446056B GB2446056B (en) | 2011-10-19 |
Family
ID=37847035
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0801245A Expired - Fee Related GB2446056B (en) | 2007-01-23 | 2008-01-23 | Method for treating a thermally loaded component |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US20080178907A1 (en) |
| DE (1) | DE102008004559B4 (en) |
| GB (1) | GB2446056B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012091616A1 (en) * | 2010-12-30 | 2012-07-05 | Государственное Образовательное Учреждение Высшего Профессионального Образования "Московский Государственный Технический Университет Имени Н.Э.Баумана" (Мгту Им. Н.Э.Баумана) | Method for the hydro-abrasive cutting of metallic sheet material |
| WO2016033612A1 (en) * | 2014-08-29 | 2016-03-03 | Hzo, Inc. | Equipment for removing protective coatings from substrates |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101722361B (en) * | 2009-11-05 | 2012-07-04 | 江苏大学 | Device and method for controlling residual stress on surface of metal microstructure |
| IT1399945B1 (en) | 2010-04-29 | 2013-05-09 | Turbocoating S P A | METHOD AND APPARATUS FOR REMOVING CERAMIC COATINGS, WITH CARBON DIOXIDE SOLID SOLID. |
| KR102036635B1 (en) | 2011-03-28 | 2019-10-28 | 삼성디스플레이 주식회사 | Organic light emitting display device and method for manufacturing the same |
| DE102011055104B4 (en) * | 2011-11-07 | 2014-07-17 | Benteler Automobiltechnik Gmbh | Method for solidifying blasting of metal components and blasting machine for carrying out the method |
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Also Published As
| Publication number | Publication date |
|---|---|
| US20080178907A1 (en) | 2008-07-31 |
| GB0801245D0 (en) | 2008-02-27 |
| DE102008004559A1 (en) | 2008-07-24 |
| GB2446056B (en) | 2011-10-19 |
| DE102008004559B4 (en) | 2017-03-16 |
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