KR20230132480A - Implanted thermal barrier coating system - Google Patents

Abstract

A method of forming a molded part and a molded part are disclosed. The method includes applying a thermal barrier coating (TBC) system to a sand core; Inserting the TBC coated sand core into a mold; and forming a cast iron part in a mold into which the TBC coated sand core is inserted.

Description

Implanted thermal barrier coating system

An embodiment relates to applying a thermal barrier coating system to a sand core in a molding process.

Regeneration is a process used in diesel engine manifolds to remove accumulated soot from filters, for example diesel particulate filters. Regeneration can be carried out, for example, passively in the exhaust heat or by adding catalyst to the filter or actively adding heat to the exhaust system. These manifolds, which can be produced, for example, by die casting and/or injection molding processes, are subjected to extreme heat, such as about 760°C, which can result in thermo-mechanical fatigue, for example cracking, in the part. exposed, allowing gases and heat to escape. Figure 7 shows critical areas of the exhaust manifold and turbo manifold where these cracks are likely to occur. The presence of these cracks prevents the exhaust manifold and/or turbo manifold from retaining heat within the manifold, preventing the regeneration process from properly removing accumulated soot.

Thermal barrier coatings (TBC) are applied to components such as combustors, high-pressure turbine blades, vanes, shrouds, etc. TBC can be applied to components to increase the operating temperature of hot gas path components, resulting in higher energy output and improved engine efficiency. TBC provides thermal insulation that allows TBC-coated components to withstand higher operating temperatures, increasing component durability and improving engine reliability. Also when TBC is applied to the manifold, the following advantages are achieved:

An embodiment relates to forming a product using a sand core. In particular, molded products may be parts specifically designed to maintain high heat, for example in engines, but prevent crack formation.

A transplanted thermal barrier coating (TBC) system is applied to the sand core prior to the casting or forming process. The TBC system may include a ceramic layer as a top coat applied to the sand core and a metal layer as a bond coat applied on the top coat. Preferably, the TBC system may also include an abradable layer as an adhesive coat applied to the sand core, after which a top coat is applied on the adhesive layer.

TBC can be applied to the sand core using a thermal spraying process. Preferably, the same thermal spray process is used for each component of the TBC system.

Embodiments include applying a thermal barrier coating (TBC) system to a sand core; Inserting the TBC coated sand core into a mold; and forming a cast iron part in a mold into which the TBC coated sand core is inserted.

In embodiments, the TBC system can include a ceramic layer and a metal layer. The method includes applying a ceramic layer over a sand core using an air plasma spary thermal spray process; and applying a metal layer onto the ceramic layer using an air plasma spray thermal spray process. The ceramic layer may include yttria stabilized zirconia, and the metal layer may include low alloy carbon steel that forms a bond coat to the cast iron. In addition, before the ceramic layer is applied, the step of preheating the sand core using an air plasma spray thermal spray process may be additionally included.

According to another embodiment, the TBC system may further include an adhesive layer. Moreover, before the ceramic layer is applied, the method may also further include applying an adhesive layer onto the sand core using an air plasma spray thermal spray process, wherein the ceramic layer is applied on the adhesive layer. The adhesive layer is NiC (nickel graphite) or a mixture of metals and polymers, such as metal-based polymer composites, especially Al-based polymers, preferably MCrAlY-based polymers, where M is for example equal to Co, Ni or Co/Ni. , it may include at least one of NiCrAl-based polymer, NiAl-based polymer, Al-bronze-based polymer, or AlSi polyester. Preferably, the polymer of the adhesive layer includes a thermoplastic polymer such as polytetrafluoroethylene (PFTE).

According to another embodiment, the sand core is one of silica sand, chromite sand, or zircon sand; bentonite; water; and inert sludge. The sand core may also contain anthracite. Additionally, either the silica sand, chromite sand or zircon sand may further include olivine, staurolite or graphite.

Embodiments include a cast iron body; and a molded part comprising a TBC system integrally molded with the inner surface of the cast iron body. Preferably the TBC system is applied according to the method of forming the molded part.

According to another embodiment, the TBC system includes a ceramic layer and a metal layer. The ceramic layer may include yttria stabilized zirconia, and the metal layer may include low alloy carbon steel. The TBC system may further comprise an adhesive layer, the adhesive layer being NiC (nickel graphite) or a mixture of metal and polymer, such as a metal-based polymer composite, preferably an Al-based polymer, more preferably a MCrAlY-based polymer (where M (e.g. the same as Co, Ni or Co/Ni), a NiCrAl based polymer, a NiAl based polymer, an Al-bronze based polymer or an AlSi polyester.

Other exemplary embodiments and advantages of the present invention may be identified by reviewing the present disclosure and accompanying drawings.

The invention is further described in the following detailed description with reference to a plurality of drawings, to which reference is made by way of non-limiting examples of exemplary embodiments of the invention, wherein like reference numerals designate like parts throughout the several views of the drawings. at:
1 illustrates a sand core for an example implementation;
Figures 2A-2F illustrate the process by which an implanted TBC system is applied to a sand core;
Figures 3A-3E illustrate an alternative to the process shown in Figures 2A-2F where the implanted TBC system is applied to the sand core without a bond coat;
Figures 4A-4G illustrate another process in which an implanted TBC system is applied to a sand core;
Figures 5A-5F illustrate an alternative to the process shown in Figures 4A-4G where the implanted TBC system is applied to the sand core without a bond coat;
Figure 6 illustrates a cross-section of a sand core with a TBC system implanted in a mold;
Figure 7 illustrates a known critical area for cracking in an engine manifold.

The details shown herein are for purposes of discussion, by way of example and in explanation of embodiments of the invention, and are presented to provide what is believed to be the most useful and easily understood explanation of the principles and conceptual aspects of the invention. . In this regard, no attempt is made to present the structural details of the invention in more detail than is necessary for a basic understanding of the invention, and the description, taken together with the drawings, will provide those skilled in the art with the understanding of how the invention in its various forms may be practically implemented. Make it clear to

Cores are used in die casting and/or injection molding processes to create the internal surfaces of components, especially those with complex geometries. 1 shows an exemplary core 10 for an engine manifold, the core may be used as a turbocharger for, for example, automobiles, sport utility vehicles, light and heavy trucks, farm equipment, marine vehicles, commercial and non-commercial vehicles, etc. It should be understood that any number of casting and/or molding processes can be used to form components for gasoline or diesel engines, such as turbocharger parts and components. In an exemplary embodiment, the core 10 is made of a sand composition comprising 75 to 85 weight percent silica sand (SiO2), chromite sand (FeCr2O4), or zircon sand (ZrSiO4); 5 to 11% by weight bentonite (clay); 2 to 4% water by weight; and 3 to 5% by weight of inert sludge. In embodiments, the silica sand, chromite sand or zircon sand may comprise a proportion of olivine, pyrophyllite or graphite and/or the composition may comprise up to 1% by weight (>0 to 1% by weight) anthracite. .

For example, cast and/or molded parts, such as those used in engines, can be exposed to extreme heat, for example around 760°C, which can cause thermo-mechanical fatigue, such as cracking in the part, as gases and heat Allows you to get out. Additionally, in components designed to retain or retain heat, such as a manifold, it is desirable for the component to be formed to prevent heat transfer through the component housing or walls to the greatest extent possible. To address these issues, embodiments relate to forming a thermal barrier coating (TBC) system on the interior surfaces of cast and/or molded parts. The TBC system may include a plurality of layers or coatings formed by thermal spraying, such as plasma spraying, high velocity oxyfuel (HVOF) spraying, or other suitable spraying processes, to deposit the powder product to form at least a ceramic layer and a metal layer. there is. By the presently described solution, complete and crack-free coverage of the inner surface of the cast and/or molded part is achieved using a thermal spraying process of TBC in combination with a sand core.

2A-2F illustrate exemplary processes for forming TBC transported on cast and/or molded parts. As shown in FIG. 2A, a sand core 20, such as the core shown in FIG. 1, is formed inside the part to be molded. In Figure 2b, TBC 21 (or ceramic layer) is applied to sand core 20 through a thermal spray process. Prior to applying the TBC 21, it may be advantageous to preheat the sand core 20, especially the sand core containing bentonite, to prevent evaporation of bonding chemicals or water within the sand during TBC application, which may unfavorably lead to poor adhesion. , may cause cracks and rupture. As a non-limiting example, the core 20 can be formed by a plasma torch or plume without supplying powder by air plasma spraying, for example from a cascaded plasma torch such as the SINPLEXPRO-90 from OERLIKON METCO (US) INC. preheating can be achieved.

The thermal barrier coating 21 protects the part to be produced from thermo-mechanical fatigue (cracking) and functions to retain heat inside the part. As a non-limiting example, if the part being produced is an engine manifold, the applied TBC 21 increases thermal management efficiency for reduced fuel consumption. Preferably, the TBC 21 has a porosity of 15% to less than 25% to prevent ingress of liquid metal during the casting process, as discussed below, for example with reference to Figure 2E, which allows the cast part to remain after solidification. This may lead to unintended creation of deposits internally (scabbing effect). Alternatively, the TBC 21 may be a porous TBC layer applied to the sand core 20 and a non-porous (dense) layer applied to the porous TBC layer, especially a porous TBC layer having a porosity of 15% to 25%. It can be applied as a double-layer system with a TBC layer, wherein the non-porous TBC layer has a porosity of from 1% to less than 15%, more preferably from 5% to 10%, to prevent penetration of liquid metal during the casting process. Additionally, TBC 21 may be applied as a gradient layer of decreasing porosity from the sand core 20 to prevent infiltration of liquid metal during the casting process. To adjust the porosity of the TBC the coating parameters can be adjusted, i.e. the power of the plasma and optionally the flow of the secondary gas, the speed and/or temperature of the deposited particles can be controlled accordingly. In an exemplary embodiment, the TBC 21 is a powder product, e.g., yttria-stabilized zirconia (YSZ), such as METCO 204NS powder by OERLIKON METCO (US) INC., having a particle size of 100 to 1000 microns, preferably 200 to 800 microns. It is formed by thermal spraying onto a sand core 20 having a thickness of microns, more preferably 400 to 500 microns.

After application of TBC 21, a bond coat 22 or metal layer is applied as shown in Figure 2c. Bond coat 22 ensures adhesion of TBC 21 to the cast part in Figure 2e. In embodiments, the bond coat 22 is a powder product, such as FeCrMnC (Fe 1.4-1.6Cr 1.4-1.6Mn 1.0-1.3C) such as METCO XPT 512 powder from OERLIKON METCO (US) INC. or OERLIKON METCO It can be a low alloy carbon steel applied to TBC 21 by thermal spraying of CoCrAlY (Co 29Cr 6Al 2Si 0.3Y), such as AMDRY 920 powder from (US) INC., up to 100 microns, preferably up to 50 microns, more preferably Typically, it can be applied at about 15 to 30 microns. However, a thicker bond coat 22 having a thickness of up to 500 microns, preferably about 100 to 500 microns, more preferably about 100 to 350 microns, may be applied to prevent penetration of liquid metal during the casting process. . Preferably, the bond coat 22 is applied in the same manner used to apply the TBC 21, i.e., by air plasma spraying from a cascade plasma torch such as a SINPLEXPRO-90 from OERLIKON METCO (US) INC.

The coated sand core 20 is then inserted into a mold 24, for example a sand mold, as shown in Figure 2d, so that an opening 23 is formed in the mold 24 to receive the casting material. In Figure 2e, a casting material 25 suitable for the part to be cast, for example gray cast iron such as ferritic cast iron SiMo51, austenitic cast iron D5S and austenitic cast stainless steel HK30, is deposited in the opening 23 for casting the part. In a conventional manner, the implanted TBC coated cast part is removed from the sand mold 24 and the sand core 20 is likewise removed.

In an alternative implementation to the one shown in Figures 2A-2F. The method can be performed without Figure 2c, i.e. without applying a bond coat after TBC 21. In this alternative embodiment illustrated in FIGS. 3A-3E , after application of the TBC 31 in FIG. 3B , the coated sand core 30 is inserted into the mold 34 in FIG. 3C and the casting material 35 is deposited in the opening 33 of the mold 34 in FIG. 3D. In a conventional manner, the implanted TBC coated cast part is removed from the mold 34 and the sand core 30 is also removed in Figure 3E.

To protect the cast and/or molded part from cracking and to ensure that the produced part retains heat within the part, a layer of TBC and bond coat should be applied to all parts in the sand mold that will form the inner surface of the part; Therefore, the liquid cast iron does not come into direct contact with the sand mold. However, thermal spraying should be avoided in functional areas of the sand mold, for example in areas where cores are placed in the mold or where the mold is assembled.

4A-4G show another example process for forming TBC transported on cast and/or molded parts. As shown in FIG. 4A, a sand core 40, such as the core shown in FIG. 1, is formed inside the part to be molded. In contrast to the exemplary embodiment of FIGS. 2A-2F, the TBC system is a thermal spray process, e.g., air plasma spray from a cascade plasma torch such as a SINPLEXPRO-90 from ERLIKON METCO (US) INC. It further includes an abrasive layer or adhesive (adhesive) layer 46 applied to 40). The adhesive layer 46 can be an aluminum silicate abrasive layer containing various polymers (AlSiPolyester), powder products such as METCO 1606, METCO 601, AMDRY 2010, AMDRY XPT 268, or AMDRY, all from OERLIKON METCO (US) INC. 2000 is applied to the sand core 40 by thermal spraying at a thickness of 20 to 500 microns, preferably about 100 to 400 microns, more preferably about 200 to 350 microns. Applying the adhesive layer 36 to the sand core 40 ensures easy deposition as a first layer because it has good affinity for the sand core 46 and has low sensitivity to thermal effects. Advantageously, in contrast to the previously described embodiments, no preheating of the sand core 40 is required before applying the adhesive layer 40 or subsequent layers.

In FIG. 4C, the TBC 41 or ceramic layer is formed using a thermal spray process, preferably the same thermal spray process used to apply the adhesive layer 46, i.e., a cascade plasma such as SINPLEXPRO-90 from OERLIKON METCO (US) INC. It is applied to the adhesive layer 46 through air plasma spraying from a torch. As in the previously described embodiments, the TBC 41 functions to protect the part to be manufactured from thermo-mechanical fatigue (cracking) and to retain heat within the part. As previously described, TBC 41 preferably has a porosity of less than 15% to 25% to avoid infiltration of liquid metal during the casting process, as discussed below, for example, with reference to Figure 4E; This can lead to the creation of unintended deposits inside the cast part after solidification (scabbing effect). Alternatively, TBC 41 may be deposited as a bilayer system or as a gradient layer (a porous TBC layer or a TBC layer with higher porosity is applied to the adhesive layer 46). In an exemplary embodiment, the TBC 41 is a powder product, e.g., thermal spraying of yttria-stabilized zirconia (YSZ), such as METCO™ 204NS powder by OERLIKON METCO (US) INC., with a particle size of 100 to 1000 microns, preferably is formed by applying it on a sand core 40 having a thickness of 200 to 800 microns, more preferably 400 to 500 microns.

After application of TBC 41, a bond coat 42 or metal layer is applied as in Figure 4d. Bond coat 42 ensures adhesion of TBC 41 to the cast part in Figure 4f. In embodiments, the bond coat 42 is FeCrMnC (Fe 1.4-1.6Cr 1.4-1.6Mn 1.0-1.3C), such as METCO CoCrAlY (Co 29Cr 6Al 2Si 0.3Y) powder, such as 920, may be applied to the TBC 41 by thermal spraying, with a thickness of up to 100 microns, preferably up to 50 microns, more preferably about 15 and 30 microns. Can be applied in microns. However, a thicker bond coat 42 with a greater thickness may be applied as described above to prevent penetration of liquid metal during the casting process. Again, the bond coat 42 is preferably applied in the same manner as used to apply the TBC 41, i.e., with an air plasma from a cascade plasma torch such as a SINPLEXPRO-90 from OERLIKON METCO (US) INC. Applied by the warrior.

The coated sand core 40 is then inserted into a mold 43, for example a sand mold, as shown in Figure 4e, so that an opening 44 is formed within the mold 43 to receive the casting material. In Figure 4f, a casting material 45 suitable for the part to be cast, for example gray cast iron such as ferritic cast iron SiMo51, austenitic cast iron D5S and austenitic cast stainless steel HK30, is deposited in the opening 44 for casting the part. In a conventional manner, the implanted TBC coated cast part is removed from the sand mold 44 and the sand core 40 is likewise removed. However, in this embodiment, the adhesive layer 46 reinforces the fracture zone between the sand core 40 and the adhesive layer 46, thereby ensuring the integrity of the TBC 41 during mechanical removal of the sand core 40 after the casting process. It functions. Without the adhesive layer 46, there is a high risk of fracture of the TBC 41.

In an alternative implementation to that shown in Figures 4A-4G. The method can be performed without Figure 4d, i.e. without applying a bond coat after TBC 41. In this alternative embodiment, illustrated in FIGS. 5A-5F after application of the TBC 51, the coated sand core 50 is inserted into the mold 54 and the casting material 55 is placed in the opening of the mold 54. (53) is deposited. In conventional fashion, the implanted TBC coated cast part is removed from the mold 54 and the sand core 50 is likewise removed.

To protect the cast and/or molded part from cracking and to ensure that the produced part retains heat within the part, a layer of adhesive, TBC and bond coat must be applied to all parts of the sand mold that will form the inner surface of the part. , Therefore, the liquid cast iron does not directly contact the sand mold. However, thermal spraying of the functional areas of the sand mold, for example the areas where cores are placed in the mold or where the mold is assembled, must be prevented.

The exemplary process does not require pretreatment such as grit blasting because the core 20 provides a rough surface for coating, and the parts for coating are used in a sprayed state, i.e., machining. There is no need for post-processing like this.

Figure 6 shows a cross section of the part still in the mold. In this example, an adhesive coat 66 (wearable base material layer) having a thickness of 264 to 300 microns is applied onto the sand core 60 and a TBC 61 (top coat-ceramic layer) having a thickness of 435 to 438 microns. ) is applied onto the adhesive coat 66 , and a bond coat 62 (metal layer) having a thickness of 19 to 23 microns is applied onto the TBC 61 . Casting material 65 is shown as cast on bond coat 62.

When the cast and/or molded parts implanted with the TBC system are engine manifolds for heavy-duty trucks, engine efficiency has been found to improve by as much as 0.5%. Fuel consumption was improved by reducing heat dissipation into the cooling system by 4% to 12% and raising the temperature of the aftertreatment (turbo) system by approximately 2%, providing more efficient conversion and a more efficient turbo system. These savings can be significant. For example, based on simple calculations, the cost savings per vehicle over a 10-year lifespan is approximately €1000 with a fuel saving of 0.2%. In particular, assuming a conservative fuel saving of 0.2%, this could result in savings of up to 1,000 liters for diesel, with an average fuel consumption of 50,000 liters per year for large trucks. However, tests have shown fuel savings of 0.5%, which could lead to savings of up to 2,500 liters over the life of the vehicle.

Note that the above-described embodiments are provided for illustrative purposes only and are in no way to be construed as limiting the invention. Although the invention has been described with reference to exemplary embodiments, the words used herein are to be understood as words of description and illustration and not of limitation. Within the scope of the appended claims, changes may be made as described and modified without departing from the scope and spirit of the invention. Although the invention has been described with reference to specific means, materials and embodiments, the invention is not limited to the specific details disclosed herein; Rather, the invention extends to all functionally equivalent structures, methods and uses as come within the scope of the appended claims.

Claims (24)

A method of forming a molded part, comprising:
Applying a thermal barrier coating (TBC) system to the sand core;
Inserting the TBC coated sand core into the mold; and
Forming a cast iron part in a mold with a TBC coated sand core inserted.
Method, including. According to paragraph 1,
The method of claim 1, wherein the TBC system includes a ceramic layer and a metal layer. According to paragraph 2,
applying a ceramic layer over the sand core using an air plasma spray thermal spray process; and
Applying a metal layer onto the ceramic layer using an air plasma spray thermal spray process.
A method further comprising: According to paragraph 2 or 3,
The method of claim 1 , wherein the ceramic layer is applied as a two-layer system with a porous TBC layer applied over the sand core and a non-porous TBC layer applied over the porous TBC layer. According to paragraph 2 or 3,
The method of claim 1, wherein the ceramic layer is applied as a gradient layer with decreasing porosity from a sand core. According to any one of claims 2 to 5,
Wherein the ceramic layer is applied at a thickness of 100 to 1000 microns, preferably 200 to 800 microns, more preferably 400 to 500 microns. According to any one of claims 2 to 6,
Wherein the metal layer is applied with a thickness of 100 to 500 microns, preferably 100 to 350 microns. According to any one of claims 2 to 6,
wherein the metal layer is applied with a thickness of at most 100 microns, preferably at most 50 microns, more preferably between 15 and 30 microns. According to any one of claims 2 to 8,
The method of claim 1, wherein the ceramic layer comprises yttria stabilized zirconia and the metal layer comprises a low alloy carbon steel forming a bond coat to cast iron. According to paragraph 3,
The method further comprising preheating the sand core using an air plasma spray thermal spray process before the ceramic layer is applied. According to any one of claims 1 to 9,
The method of claim 1, wherein the TBC system further comprises an adhesive layer. According to clause 11,
Wherein the adhesive layer is applied with a thickness of 20 to 500 microns, preferably 100 to 400 microns, more preferably 200 to 350 microns. According to claim 11 or 12,
Before the ceramic layer is applied, the method further comprises applying an adhesive layer onto the sand core using an air plasma spray thermal spray process, wherein the ceramic layer is applied on the adhesive layer. According to any one of claims 11 to 13,
The adhesive layer is at least one of NiC or a mixture of metal and polymer, such as a metal-based polymer composite, preferably an Al-based polymer, more preferably an MCrAlY-based polymer, a NiCrAl-based polymer, a NiAl-based polymer, an Al-bronze-based polymer or A method comprising at least one of AlSi polyester. According to any one of claims 1 to 14,
The sand core is
either silica sand, chromite sand, or zircon sand;
bentonite;
water; and
inert sludge
Method, including. According to clause 15,
The method of claim 1, wherein the sand core further comprises anthracite. According to claim 15 or 16,
wherein one of the silica sand, chromite sand, or zircon sand further comprises olivine, chromite, or graphite. As a molded part,
Cast iron body; and
TBC system molded integrally with the inner surface of the cast iron body
Including, molded parts. According to clause 18,
A molded part formed by the method according to any one of claims 1 to 17. According to clause 18,
The molded part, wherein the TBC system includes a ceramic layer and a metal layer. According to claims 18 and 20,
The molded part, wherein the ceramic layer comprises yttria stabilized zirconia and the metal layer comprises low alloy carbon steel. According to claims 18, 20 and 21,
The molded part, wherein the TBC system further comprises an adhesive layer. According to clause 22,
The adhesive layer is at least one of NiC or a mixture of metal and polymer, such as a metal-based polymer composite, preferably an Al-based polymer, more preferably an MCrAlY-based polymer, a NiCrAl-based polymer, a NiAl-based polymer, an Al-bronze-based polymer or A molded part comprising at least one of AlSi polyester. According to any one of claims 18 to 23,
The molded part is one of a turbocharger part, an exhaust manifold or a turbo manifold.