JP3769065B2 - Zirconia-coated member, manufacturing method thereof, manufacturing apparatus thereof, and turbine member - Google Patents

Description

【００７８】
金属基材温度を７００℃以上としてジルコニア被覆層の成膜を行うことにより（２００）および（００２）の占める面積比が８０％以上となり、格段の剥離寿命の向上が得られた。また、このときの柱状晶は大きく成長した一個の結晶粒となっていた。
【００７９】
【発明の効果】
以上説明したように、本発明によれば、機械的強度に優れた結晶構造の被覆層が得られ、高温雰囲気中での長期間の使用や熱サイクル運転に対しても、ジルコニア被覆層の割れや剥離の発生を防止することができる極めて優れたジルコニア被覆部材を提供することができる。
【００８０】
またジルコニア被覆層の形成を好ましくは金属基材を７００℃以上の温度で均一に加熱しながら行うことにより、結晶方位および柱状晶のミクロ組織を制御することができる。さらに好ましくは結合層を減圧プラズマ溶射あるいは物理蒸着法で形成することにより、高温酸化特性にもより優れ、長時間にわたってより安定した、割れや剥離のより起こりにくいジルコニア被覆部材を提供することができる。
【図面の簡単な説明】
【図１】本発明にかかるジルコニア被覆部材の断面図である。
【図２】本発明にかかるジルコニア被覆部材の製造装置の概略構成図である。
【図３】本発明にかかるジルコニア被覆部材の製造装置の一部である金属基材加熱装置の概略構成図である。
【図４】本発明にかかるジルコニア被覆部材の製造装置の好適態様の概略構成図である。
【図５】従来のジルコニア被覆部材の断面図である。
【図６】実施例３および４におけるジルコニア被覆時の温度分布を示すグラフである。
【符号の説明】
１ 金属基材
２ 結合層
３ ジルコニア被覆層
４ 真空チャンバー
５ ルツボ
６ ジルコニアターゲット材
７ 金属基材駆動装置
８ 金属基材加熱装置
９ ヒータエレメント
１０ 防熱板
１１ 加熱装置支え
１２ 扉
１３ 従来品の結合層
１４ 従来品のジルコニア被覆層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a zirconia-coated member suitably used in a high-temperature or high-temperature corrosive environment, a manufacturing method thereof, and a manufacturing apparatus thereof.
[0002]
[Prior art]
In general, in a gas turbine plant for power generation and the like, in order to improve power generation efficiency, the temperature of the gas turbine is increased. With this increase in temperature, it is desired to improve the heat-resistant temperature and high-temperature oxidation resistance of gas turbine members. Ni-based or Co-based heat-resistant alloys have been developed as materials for these members, and the heat-resistant temperature has also been improved. . However, the heat resistant temperature is limited to about 850 ° C.
[0003]
Therefore, ceramic materials have been studied for the purpose of further increasing the durability at high temperatures. However, the use of the ceramic materials as a structural material has a problem in toughness and the like as compared with metal materials, and has not yet been fully applied. Therefore, in order to cope with the high temperature of such a member, means for preventing the member from becoming high temperature have been actively studied.
[0004]
That is, one of such methods is a method of cooling the member, and the other method is a method of coating the surface of the member with ceramic having a low thermal conductivity.
[0005]
Such a coating is called a thermal barrier coating, and can suppress the substantial temperature of the metal substrate by 50 ° C. to 100 ° C. as compared with a coating without a thermal barrier coating. And there exists zirconia as a ceramic which comprises this thermal barrier coating. In addition to excellent mechanical properties, zirconia has the advantage of low thermal conductivity.
[0006]
By the way, zirconia has three crystal structures of monoclinic, tetragonal, and cubic. Tetragonal is the most excellent from the viewpoint of mechanical properties. Pure zirconia (ZrO₂) Is a stable phase of monoclinic crystals at room temperature, but reversibly changes from monoclinic to tetragonal at around 1000 ° C and from tetragonal to cubic at around 2300 ° C as the temperature is raised. Metastasize. The occurrence of this phase transition and the volume change associated therewith are impeding practical use of pure zirconia. That is, during the cooling process in the zirconia sintering process, zirconia undergoes a phase transition from tetragonal to monoclinic crystals that are inferior in mechanical properties, and at that time, large volume expansion occurs. Fear is high. In order to eliminate the phase transition during this cooling process, Y is usually used so that tetragonal crystals and cubic crystals having excellent mechanical properties are carried over to room temperature, that is, to stabilize the high-temperature phase.₂O₃And compounds such as CaO and MgO are added. Thereby, the phase transition from the tetragonal crystal to the monoclinic crystal generated in the cooling process can be suppressed, and a tetragonal crystal or cubic crystal having excellent mechanical properties from room temperature to high temperature can be obtained.
[0007]
Further, since the thermal barrier coating is coated with a ceramic having different physical property values from the heat-resistant alloy constituting the metal substrate, there is a problem in the adhesion strength between the metal substrate and the zirconia coating layer and its reliability. Especially in gas turbines, etc., the thermal cycle caused by repeated starting and stopping causes high-temperature oxidation and high-temperature corrosion of the metal substrate surface, resulting in a decrease in mechanical strength and chemical resistance at high temperatures, resulting in peeling of the zirconia coating layer. Damage such as dropping off occurs.
[0008]
Therefore, as a method for solving such problems, there is a method in which a bonding layer made of a metal alloy layer is provided between the metal substrate and the zirconia coating layer. As this bonding layer, a so-called MCrAlY-based alloy containing Ni or Co having a property excellent in high-temperature oxidation resistance and high-temperature corrosion as a main component and adding Cr, Al, Y, or the like is often used. And the zirconia coating layer used for such a bonding layer or thermal barrier coating is mainly formed by the atmospheric plasma spraying method. In this case, the adhesion mechanism between the zirconia coating layer and the bonding layer is merely mechanical bonding, and its strength is 2 to 5 kg / mm.²It is said that. Thus, the reason why the zirconia coating layer used for the bonding layer and the thermal barrier coating is mainly formed by the atmospheric plasma spraying method is that the coating formation speed is high and the economy is excellent.
[0009]
However, the bonding layer and the zirconia coating layer formed by the atmospheric plasma spraying method have many pores. Since these are used in a high temperature corrosive environment including corrosive impurities in the fuel, the bonding layer having a porous structure with many pores and the zirconia coating layer have problems of high temperature oxidation and high temperature corrosion of the bonding layer. The bonding layer is a component excellent in oxidation resistance and corrosion resistance, but depending on the formation method thereof, the bonding layer does not necessarily exhibit the oxidation resistance and corrosion resistance expected of the original alloy material.
[0010]
According to the result of thermal cycle test under the high temperature oxidation or high temperature corrosive environment, the durability of the thermal barrier coating composed of the bonding layer and the zirconia coating layer formed by atmospheric plasma spraying is extremely low. It has been found that the coating layer peels off. This is because the bond between the bonding layer and the zirconia coating layer is inherently mechanical and weak in strength, and the bonding layer surface at the boundary is oxidized or corroded, further reducing its adhesion. it is conceivable that. Further, many peelings of the zirconia coating layer occur not only in the interface with the bonding layer but also in the zirconia coating layer.
[0011]
[Problems to be solved by the invention]
In view of such points, the object of the present invention is to ensure mechanical strength and to prevent cracking and peeling in the zirconia coating layer for a long period of time even if the thermal cycle in a high temperature oxidation and high temperature corrosive environment is repeated. It is an object to provide a zirconia-coated member which hardly occurs, a manufacturing method and a manufacturing apparatus for the same.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the present inventors have conducted research on the crystal structure and the film structure of the zirconia coating layer, and as a result, ensured the excellent mechanical properties of the zirconia coating layer and in a high-temperature atmosphere. It has been found that it is important to control the crystal structure and the microstructure of the columnar crystals in order to increase the peeling life.
[0013]
Here, the present invention relates to a metal substrate, a bonding layer coated on the metal substrate, and ZrO coated on the bonding layer.₂A zirconia-coated member comprising a zirconia-coated layer containing as a main component, wherein the crystal constituting the zirconia-coated layer comprises 90% or more of tetragonal crystals composed of columnar crystals. It is a member.
[0014]
In the present invention, preferably, the crystal having orientation in the Miller index (200) and / or (002) orientation is 80% or more in area ratio on the surface of the zirconia coating layer, and the metal base material is Ni, It contains at least one of Cr and Co, and the bonding layer is made of an M-Cr-Al-Y layer (where M represents at least one of Ni, Co, and Fe). Thus, each crystal grain composed of columnar crystals of the zirconia coating layer grows as one crystal.
[0015]
Moreover, this invention is a turbine member which comprises the said zirconia coating | coated member.
[0016]
In the method for producing a zirconia-coated member of the present invention, the bonding layer is formed on the metal substrate, and the zirconia coating layer is further formed on the bonding layer by a physical vapor deposition method. Preferably, the bonding layer is reduced in pressure. It is formed by plasma spraying or physical vapor deposition.
[0017]
In the method for producing a zirconia-coated member according to the present invention, preferably, in the formation of the zirconia-coated layer, ZrO₂CaO, MgO, Y₂O₃, CeO₂The target material is evaporated by irradiating an electron beam to a zirconia target material containing any one or more of the above, and forming the target material on the bonding layer, and during the film formation, the metal The base material is continuously heated. Preferably, the metal base material temperature is 700 ° C. or higher and is kept below the solution treatment temperature of the metal base material, and only the metal base material is locally heated.
[0018]
The apparatus for producing a zirconia-coated member of the present invention comprises a metal substrate heating device for locally heating only the metal substrate at the time of film formation of the zirconia coating layer, around the metal substrate, Preferably, the metal base material disposing device is disposed at a position where the radiant heat from the metal base material heating device is focused, and a heat sensor for measuring the temperature of the metal base material is provided in the vicinity of the metal base material. The signal from the heat sensor is fed back to the metal substrate heating device.
[0019]
Preferably, the apparatus for manufacturing a zirconia-coated member of the present invention is a batch type apparatus in which a plurality of the metal base material heating devices are independently arranged around the metal base material, and a door is provided, for example, the door is opened and closed. And a batch type furnace to which the metal substrate is attached, wherein one or more metal substrate heating devices are arranged on the door. Preferably, the metal heating device is provided with a heater element made of graphite, and the heater element is exposed at a portion of the metal heating device facing the metal substrate. This part is surrounded by a heat insulating plate. More preferably, a plurality of the heat sensors are arranged, and signals from the heat sensors are fed back to the plurality of metal substrate heating devices, respectively, so that the plurality of metal substrate heating devices are independently provided. It is the manufacturing apparatus of the zirconia coating | coated member made to control.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be specifically described.
First, the zirconia covering member will be described.
[0021]
FIG. 1 is a cross-sectional view showing a specific example of a zirconia-coated member of the present invention. On a bonding layer 2 formed by coating on a metal substrate 1, a tetragonal crystal composed of columnar crystals is measured by X-ray diffraction. A zirconia coating layer 3 containing 90% or more is formed.
[0022]
The material of the metal substrate can be appropriately selected from heat-resistant metal materials according to the purpose, but preferably contains at least one of Ni, Cr, Co, more preferably Ni, Cr, Co. A heat-resistant metal having at least one kind as a main component is used.
[0023]
The bonding layer is a heat-resistant material and is not particularly limited as long as it is in close contact with the metal material and the zirconia coating layer. However, the bonding layer is mainly composed of Ni or Co having excellent resistance to high-temperature oxidation and high-temperature corrosion. So-called MCrAlY-based alloys to which Al, Y, etc. are added are preferred. Preferably, it is a dense layer with few pores. In the present specification, a structure in which a bonding layer is provided on a metal substrate may be simply referred to as a metal substrate.
[0024]
The material of the zirconia coating layer in the present invention is ZrO.₂As the main component, Y₂O₃Zirconia to which a high-temperature phase is stabilized, to which CaO, MgO or the like is added, preferably ZrO₂85-95 average weight percent and Y₂O₃5 to 15% by weight average.
[0025]
In the preferred embodiment of the present invention, the orientation of the zirconia coating layer is particularly defined for the following reason.
[0026]
Cracking / peeling of the zirconia coating layer occurs when the crack propagates parallel to the bonding layer. When the crack progresses easily, the inventors of the present invention have a cleavage plane that is most easily peeled in the film crystal structure, that is, the Miller index (111) plane is laminated in parallel to the bonding layer, and the crystal ratio is I found out that it was time to increase. In other words, the zirconia coating layer has a crystal structure in which the (111) plane is not parallel to the bonding layer, so that the mechanical strength is excellent, and the zirconia is not easily cracked or peeled off even in a long-time thermal cycle operation. A coating layer can be provided.
[0027]
Therefore, in the present invention, the crystal having orientation in the Miller index (111) orientation among the crystals is 70% or less, preferably 50% or less, more preferably 20% or less in terms of the area ratio on the zirconia-coated surface. .
[0028]
In the present invention, preferably, the crystal of the zirconia coating layer is orientated in the directions of (200) and (002), so that the (111) plane that easily causes peeling does not become parallel to the bonding layer, and A coating with high mechanical strength can be provided.
[0029]
In the preferred embodiment of the present invention, the ratio of the orientation of the zirconia coating layer to the (200) or (002) plane or the presence of the mixed orientation plane is preferably an area ratio on the surface of the zirconia coating layer. 80% or more, more preferably 95% or more, it is possible to provide a zirconia coating layer that is particularly excellent in mechanical strength and that does not cause cracking or peeling of the film even in a long-time thermal cycle operation.
[0030]
In addition, even if crystal planes {HKL} = (311), (113), (220), and (202) other than (200) and (002) exist, the superiority or inferiority thereof does not change.
[0031]
Furthermore, in addition to controlling the crystal orientation, the microstructure of each columnar crystal is made into a structure in which the fine crystal grains to be laminated are integrated with each other, so that the mechanical strength and the peeling life are improved. An excellent film structure can be obtained.
[0032]
This is because, for example, the (111) plane that is easily peeled off decreases, and the crystal structure also becomes a desirable orientation plane.
[0033]
The zirconia coating layer according to the present invention is preferably a dense layer having few pores.
[0034]
The zirconia-coated member of the present invention is suitably used for various engines, boilers and the like in addition to being suitably used for turbine members.
[0035]
Next, the manufacturing method and apparatus of the present invention will be described with specific examples.
In producing the zirconia-coated member of the present invention, a bonding layer is preferably formed on a metal substrate produced by a conventional method, preferably by low pressure plasma spraying or physical vapor deposition, and further, physical vapor deposition is performed on the bonding layer. To form a zirconia coating layer.
[0036]
When forming a zirconia coating layer, for example, when a zirconia target material is evaporated by electron beam irradiation / heating and coated on a metal substrate, a film is formed by the evaporated molecules, so the structure of the film is a crystal composed of columnar crystals. And the crystal orientation and microstructure can be controlled.
[0037]
Specifically, for example, it is manufactured as follows.
[0038]
The surface of a heat-resistant metal substrate, for example, a metal substrate composed mainly of at least one of Ni, Cr, and Co is roughened by degreasing and blasting using alumina particles or the like. Next, this metal substrate is mounted in a vacuum chamber and evacuated to a predetermined degree of vacuum, and then Ar, He, H₂, N₂The pressure is set to several tens of Torr in an atmosphere of any one of these or a combination thereof.
[0039]
Next, after generating plasma and heating the metal substrate to several hundred degrees C., Cr, Al is contained in any one of Ni, Co, Fe, or a combination thereof, and Hf, Ta, Y, Si, Zr. Thermal spray powder composed of any one or a combination thereof is mixed with plasma to coat the surface of the metal substrate.
[0040]
Thus, the bonding layer formed by low-pressure plasma spraying in this way becomes a very dense film with almost no oxides or pores in the film, compared with the bonding layer formed by atmospheric plasma spraying. Is greatly improved.
[0041]
The tie layer can also be formed by physical vapor deposition with zirconia coating. According to this, it is possible to form a very dense bonding layer having almost no oxides or pores in the bonding layer, and to smooth the bonding layer surface and to make the surface of the zirconia coating layer very smooth. In addition, the crystal orientation can be easily controlled.
[0042]
On the bonding layer thus formed, zirconia is coated with a ceramic (zirconia) coating apparatus. As this zirconia coating apparatus, a general ceramic coating apparatus capable of forming a ceramic film by physical vapor deposition can be used.
[0043]
In FIG. 2, the suitable example of the zirconia coating apparatus of this invention is shown. The zirconia coating apparatus includes a vacuum chamber 4, a vacuum exhaust device (not shown), and a control device and a power supply device (not shown). A control device (not shown) is provided with means for controlling evacuation, electron beam current, electron beam scanning, metal substrate heating, metal substrate drive, and the like.
[0044]
A crucible 5 is disposed in the lower portion of the vacuum chamber 4, and a zirconia target material 6 is attached to the crucible 5.
[0045]
On the other hand, a metal base material driving device 7 that is rotationally driven by a motor (not shown) is provided in the upper part of the vacuum chamber 4, and the metal base material 1 is mounted on the metal base material driving device 7. A metal base material heating device 8 for locally heating the metal base material 1 is disposed around the metal base material 1 inserted into the metal base material driving device 7.
[0046]
Therefore, when the zirconia is coated on the metal substrate 1 coated with the bonding layer, first, the zirconia target material 6 is mounted on the crucible 5 in the vacuum chamber 4, and the metal substrate 1 is attached to the metal substrate driving device. 7 and the inside of the vacuum chamber 4 is 10^-2-10^-FourVacuum is drawn until the degree of vacuum is Pa.
[0047]
Next, the surface of the zirconia target material is melted by irradiating the zirconia target material 6 with an electron beam by an electron beam generator (not shown). At this time, the electron beam current is controlled so that a predetermined evaporation rate is maintained while the surface is always melted, and further the electron beam is scanned.
[0048]
While the metal substrate 1 is coated with zirconia, the metal substrate 1 is rotated by the metal substrate driving device 7 and heated to 700 ° C. or more by the metal substrate heating device 8. The metal substrate heating device 8 has a structure for locally heating only the metal substrate 1.
[0049]
In the present invention, when controlling the crystal of the film, that is, controlling the orientation and the microstructure, the heating of the metal substrate from the start of film formation until the film formation is completed, particularly 700 ° C. or higher, preferably 750 ° C. As described above, it is more preferable to keep the temperature at 800 ° C. or higher, and to control the heating temperature with high precision so that the entire metal base is uniformly heated at a predetermined temperature.
[0050]
When the heating temperature of the metal substrate is 700 ° C. or lower, the crystal orientation plane of the zirconia coating layer tends to be in the (111) direction. This is because the growth energy of the crystal is small, so that the evaporated zirconia atoms form the most packed density surface, that is, the (111) surface, which is easily stacked.
[0051]
On the other hand, by setting the heating temperature of the metal substrate to 700 ° C. or higher, the crystal orientation plane can be changed to a plane other than (111), and the ratio of (200) and (002) is increased as the temperature is increased. Can be increased.
[0052]
In addition, by bringing the heating temperature to 700 ° C. or higher and continuing the heating until the film formation is completed, the fusion and integration of the fine crystal grains to be laminated proceeds. Further, as the temperature is raised, this fusion integration is promoted, and each columnar crystal becomes one crystal. It was also found that the columnar crystals that became one crystal body had a very strong film structure against thermal stress, and were excellent in heat stress and peel resistance.
[0053]
The upper limit of the heating temperature is preferably the solution treatment temperature of the metal substrate in order to prevent the mechanical properties of the metal substrate from deteriorating.
[0054]
Moreover, it is preferable to use only the metal substrate for local heating because it prevents the entire vacuum chamber from being heated at a high temperature and does not require a large facility cost for the vacuum device configuration.
[0055]
FIG. 3 is a schematic configuration diagram of a metal base material heating device which is a part of the zirconia-coated member manufacturing apparatus according to the present invention. FIG. 3- (a) shows a diagram in which the metal substrate 1 is disposed in the metal substrate heating apparatus 8, and a diagram viewed from the direction A, with FIG. 3- (b) and another example shown in FIG. 3- (c). Shown in
[0056]
The metal substrate heating device 8 includes a heater heating element (not shown) and a heat insulating plate disposed around the heater heating element.
[0057]
In the example shown in FIG. 3B, the metal substrate 1 is disposed in a semi-cylindrical metal substrate heating device 8, and the metal substrate heating device 8 and the zirconia target material 6 are made of a metal substrate. It is comprised so that it may arrange | position on the concentric circle centering on the material 1. FIG. By doing in this way, the radiant heat from the zirconia target material 6 and the metal base material heating apparatus 8 is uniformly irradiated to the metal base material 1, and the whole metal base material 1 is heated uniformly. FIG. 3C is another example having the same effect, and includes a U-shaped metal substrate heating device 8 disposed at equal intervals from the metal substrate 1.
[0058]
FIG. 4 shows a more preferred example of the zirconia coating apparatus of the present invention. Inside the vacuum chamber 4, a plurality of independent metal substrate heating devices 8 are arranged. The metal substrate heating device 8 includes a heater element 9 made of graphite and a heat insulating plate 10 disposed around the heater element 9. The heater element 9 can improve the thermal efficiency by exposing the part facing the metal substrate 1 and covering the other part with the heat insulating plate 10. The zirconia evaporated from the zirconia target material 6 on the crucible 5 also adheres to the entire metal substrate heating device 8, but the zirconia attached to the heater element made of graphite can be easily scraped off, resulting in a decrease in thermal efficiency. Can be prevented.
[0059]
One of the heating devices 8 is fixed to the upper portion of the vacuum chamber 4 by a heating device support 11, and another one of the heating devices 8 is fixed to the rear side surface of the vacuum chamber 4. On the other hand, another unit of the heating device 8 is fixed to the door 12 of the vacuum chamber 4.
[0060]
When the door 12 is closed, the metal substrate 1 is surrounded by a plurality of heating devices 8 as shown in FIG. By doing in this way, the radiant heat from the zirconia target material 6 and the metal base material heating apparatus 8 is uniformly irradiated to the metal base material 1, and the whole metal base material 1 is heated uniformly.
[0061]
When the metal substrate 1 is detached from the vacuum chamber 4 at a predetermined position, the metal substrate 1 can be easily detached from the door 12 side by opening the heating device 8 and the door 12 together. By the way, the part located on the metal substrate driving device 7 side of the metal substrate 1 has more heat escaping through the metal substrate driving device 7, and the metal substrate 1 usually has a complicated three-dimensional shape. Therefore, the temperature distribution of the metal substrate 1 tends to be non-uniform.
[0062]
In the present invention, it is particularly necessary to make the temperature distribution of the entire metal substrate 1 uniform and to control the temperature precisely to a predetermined temperature. For this reason, the metal base material heating device 8 is preferably composed of a plurality of heating devices and can be controlled independently of each other. In addition, a plurality of thermocouples, which are heat sensors for temperature control, are inserted into the drive shaft of the metal base material driving device 7 and arranged at the portion closest to the metal base material 1.
[0063]
By using the signal from the thermocouple as a control signal for the substrate heating device 8, accurate temperature control can be performed at a predetermined temperature.
[0064]
Thus, by arranging a plurality of heating devices around the metal substrate 1 and further arranging a heat sensor in the vicinity of the metal substrate 1, uniform heating can be performed at the time of film formation, and crystals of the zirconia coating layer can be obtained. The structure and microstructure can be controlled more precisely.
[0065]
In addition, since this heating method is local heating in the vicinity of the metal base material, the entire vacuum chamber is prevented from being heated at high temperature, and a large equipment cost is not required for the vacuum device configuration.
[0066]
Thus, according to the preferred embodiment of the production method of the present invention, the metal substrate is uniformly heated at a temperature of 700 ° C. or higher until the film formation is completed, and the crystal structure of the zirconia coating layer is (200) (002) mainly Further, each columnar crystal becomes a single crystal, and therefore, a zirconia coating layer having excellent mechanical strength, excellent long-term use at high temperatures and excellent heat cycle characteristics can be formed.
[0067]
【Example】
Hereinafter, the present invention will be described based on examples.
In the examples according to the present invention, when the zirconia coating layer was formed, the heating temperature of the metal base material was varied in a range from 400 ° C to 900 ° C. Further, when the metal substrate temperature was 700 ° C., it was formed by comparing the uniform temperature distribution on the metal substrate 1 with the non-uniform one.
[0068]
First, after degreasing and cleaning a Co-based FSX414 base material (made by Ishikawajima Precision Casting Co., Ltd.), blasting is performed using an alumina grid, and an alloy powder composed of Co, Ni, Cr, Al, and Y is added to 20 Torr Ar Thermal spraying was performed using Ar-He plasma in an atmosphere to obtain a film excellent in high temperature oxidation and high temperature corrosion. The thickness of the film was uniform and was about 150 μm.
[0069]
Next, 8% Y is added to the CoNiCrAlY layer.₂O_Three-ZrO₂A zirconia coating layer was formed. For this formation, the apparatus shown in FIG. 2 was used. First, in the vacuum chamber 4, the metal substrate 1 made of the FSX414 substrate was mounted on the metal substrate driving device 7, and the zirconia target material 6 was mounted on the crucible 5.
[0070]
Then, the inside of the vacuum chamber 4 is 10^-FourAfter evacuating to the Pa level, the metal substrate 1 was rotated while being heated at each temperature, and the zirconia target material 6 was evaporated with an electron beam to form a film on the metal substrate. At this time, the scanning of the electron beam was controlled in order to keep the film forming rate substantially constant. The film thickness obtained was about 150 μm.
[0071]
The conventional product was manufactured by atmospheric plasma spraying using a metal base material, a bonding layer and a zirconia coating layer made of the same material as in the above example, and had the same thickness as in the above example. A cross-sectional view of this conventional zirconia-coated member is shown in FIG. As in FIG. 1, this conventional product also has a bonding layer 13 coated on a metal substrate 1 and a zirconia layer 14 formed thereon. However, the conventional product has many pores in the bonding layer and the zirconia coating layer.
[0072]
For these conventional products and examples, metal substrate temperature distribution was controlled, and X-ray diffraction (crystal structure) and thermal cycle tests were conducted.
The heat cycle test was carried out by determining the number of heat cycles until the zirconia coating layer was peeled off, assuming that the heat cycle was held at 1000 ° C. for 30 minutes in an air atmosphere and then held in water at 20 to 25 ° C. as one cycle. . Table 1 shows the results.
Table 1 (Comparison between conventional products and examples)
Specimen Base material temperature (° C) Crystal structure Thermal cycle number until film peeling
Conventional 1-Tetragonal and monoclinic mixed 92
Conventional product 2-Same as above 79
Conventional product 3-Same as above 105
Example 1 400 * 90% or more tetragonal crystal 260
Example 2 600 * Same as above 330
Example 3 700 Same as above 1050
Example 4 700 * same as above 5750
Example 5 800 * Same as above 8500
Example 6 900 * same as above 8650

(Note) * indicates temperature control so that the temperature distribution of the metal substrate is uniform.
FIG. 6 shows the difference in temperature distribution between Example 4 in which the temperature control is precise and the temperature distribution of the metal substrate is made uniform, and Example 3 in the case where it is not.
As shown in Table 1, the conventional zirconia coating layer had a crystal structure composed of tetragonal crystals and monoclinic crystals. On the other hand, the zirconia coating layer according to the present invention has a crystal structure composed of tetragonal crystals of 90% or more. Further, in the conventional zirconia coated member, peeling of the zirconia coating layer occurred in 79 to 105 thermal cycles. On the other hand, in the examples according to the present invention, the number of thermal cycles is about three times or more. In particular, the temperature of the base material is set to 700 ° C. or higher to precisely control the temperature distribution of the metal base material. By doing so, a remarkable improvement in the peeling life is obtained.
[0073]
In the thermal cycle test result of Example 3 having a large variation in temperature distribution, the zirconia coating layer began to peel quickly, and the number of thermal cycles until film peeling was shorter than that in Example 4 where the variation in temperature distribution was small.
[0074]
Thus, it can be confirmed that the zirconia-coated member according to the present invention is superior in mechanical strength and thermal cycle characteristics as compared with conventional zirconia-coated members.
[0075]
Next, in these conventional products and examples, the substrate temperature was changed from 600 to 900 ° C. by 50 ° C., the crystal orientation was measured by X-ray diffraction, and the structure of the zirconia coating layer surface was observed by an electron microscope.
[0076]
In the structure observation, the ratio of (111) and (200) (002) to the zirconia coating layer surface was determined. Table 2 shows the results.
[0077]

[0078]
By forming the zirconia coating layer at a metal substrate temperature of 700 ° C. or higher, the area ratio occupied by (200) and (002) was 80% or higher, and a remarkable improvement in the peeling life was obtained. In addition, the columnar crystal at this time was one crystal grain which grew greatly.
[0079]
【The invention's effect】
As described above, according to the present invention, a coating layer having a crystal structure excellent in mechanical strength can be obtained, and cracking of the zirconia coating layer can be achieved even for long-term use in a high-temperature atmosphere and thermal cycle operation. And an extremely excellent zirconia-coated member that can prevent the occurrence of peeling.
[0080]
The formation of the zirconia coating layer is preferably carried out while uniformly heating the metal substrate at a temperature of 700 ° C. or higher, whereby the crystal orientation and the microstructure of the columnar crystals can be controlled. More preferably, by forming the bonding layer by low-pressure plasma spraying or physical vapor deposition, it is possible to provide a zirconia-coated member that is superior in high-temperature oxidation characteristics, is more stable over a long period of time, and is less susceptible to cracking and peeling. .
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a zirconia-coated member according to the present invention.
FIG. 2 is a schematic configuration diagram of a zirconia-coated member manufacturing apparatus according to the present invention.
FIG. 3 is a schematic configuration diagram of a metal base material heating device which is a part of a manufacturing apparatus for a zirconia-coated member according to the present invention.
FIG. 4 is a schematic configuration diagram of a preferred embodiment of a manufacturing apparatus for a zirconia-coated member according to the present invention.
FIG. 5 is a cross-sectional view of a conventional zirconia-coated member.
6 is a graph showing a temperature distribution during zirconia coating in Examples 3 and 4. FIG.
[Explanation of symbols]
1 Metal substrate
2 bonding layers
3 Zirconia coating layer
4 Vacuum chamber
5 crucible
6 Zirconia target material
7 Metal substrate drive device
8 Metal substrate heating device
9 Heater element
10 Heat insulation plate
11 Heating device support
12 doors
13 Conventional bonding layer
14 Conventional zirconia coating layer

Claims (10)

A metal substrate containing at least one of Ni, Cr and Co;
A bonding layer formed on the metal substrate and comprising an M-Cr-Al-Y layer (wherein M represents at least one of Ni, Co, and Fe);
The coated formed on the bond layer, ZrO2 and 85 to 95 wt%, a zirconia coating member formed comprises a zirconia coating layer formed of a Y2 O3 5 to 15% by weight,
The zirconia coating layer is characterized in that the crystal constituting the zirconia coating layer contains 90% or more of tetragonal crystals made of columnar crystals and each crystal grain made of the columnar crystals grows as one crystal. Element.   A turbine member comprising the zirconia-coated member according to claim 1. On a metal substrate containing at least one of Ni, Cr and Co,
A bonding layer composed of an M-Cr-Al-Y layer (wherein M represents at least one of Ni, Co, and Fe) is formed by low pressure plasma spraying or physical vapor deposition in an inert gas atmosphere;
Further, the binding layer on the ZrO2 85 to 95 wt%, in forming a zirconia coating layer comprising the Y2 O3 5 to 15 wt%, the main component ZrO2, zirconia target material comprising a Y. 2O 3, The target material is deposited on the bonding layer by a physical vapor deposition method that evaporates the target material by irradiating an electron beam,
And during the said film-forming, the temperature distribution of the said metal base material is kept at 750 degreeC or more and 900 degrees C or less and solution treatment temperature below, and it continues heating, The manufacturing method of the zirconia coating | coated member characterized by the above-mentioned. An apparatus for performing the method for manufacturing the zirconia-coated member according to claim 3,
A vacuum chamber;
A vacuum exhaust device connected to the vacuum chamber;
An electron beam generator housed inside the vacuum chamber;
A metal substrate heating device that is housed in the upper part of the vacuum chamber and is disposed in the vicinity of the metal substrate to locally heat only the metal substrate during the formation of the zirconia coating layer;
A metal substrate driving device installed outside the vacuum chamber and rotating the metal substrate;
A crucible housed in the lower part of the vacuum chamber;
An apparatus for manufacturing a zirconia-covered member, comprising a zirconia target material disposed inside the crucible.   The apparatus for producing a zirconia-coated member according to claim 4, wherein a plurality of the metal substrate heating devices are independently arranged around the metal substrate.   The zirconia coating member manufacturing apparatus according to claim 4 or 5, wherein the zirconia coating member is an apparatus for disposing the metal base material at a position where radiant heat from the metal base material heating device is focused. Manufacturing equipment for members.   The manufacturing apparatus of the said zirconia coating | coated member is a batch type apparatus by which a door is provided, and arrange | positions the 1 or more said metal base material heating apparatus in the said door in any one of Claims 4-6 The manufacturing apparatus of the zirconia coating | coated member of description.   The metal heating device is provided with a heater element made of graphite, the heater element is exposed at the portion of the metal heating device facing the metal base, and the other part of the metal heating device is heat-proof. The apparatus for manufacturing a zirconia-coated member according to any one of claims 4 to 7, which is surrounded by a plate.   The heat sensor for measuring the temperature of the metal substrate is disposed in the vicinity of the metal substrate, and a signal from the heat sensor is fed back to the metal substrate heating device. The manufacturing apparatus of the zirconia coating | coated member of description.   A plurality of the heat sensors are arranged, and signals from the heat sensors are fed back to the plurality of metal base material heating devices, and the plurality of metal base material heating devices are independently controlled. The manufacturing apparatus of the zirconia coating | coated member of Claim 9.

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