JP5606125B2 - Thermal spray powder manufacturing method, turbine member, and gas turbine - Google Patents

Description

  The present invention relates to a thermal spray powder manufacturing method, a turbine member, and a gas turbine, and more particularly, to a thermal spray powder manufacturing method, a turbine member, and a gas turbine used as a top coating of a thermal barrier coating having excellent durability.

In recent years, increasing the thermal efficiency of thermal power generation has been studied as one of the energy saving measures. In order to improve the power generation efficiency of the power generation gas turbine, it is effective to raise the gas inlet temperature, and the temperature may be about 1500 ° C. in some cases. And in order to implement | achieve high temperature of an electric power generating apparatus in this way, it is necessary to comprise the stationary blade and moving blade which comprise a gas turbine, or the wall material of a combustor with a heat-resistant member. However, although the material of the turbine blade is a refractory metal, it still cannot withstand such a high temperature. Therefore, the oxide ceramics is formed on the base material of the refractory metal by a film forming method such as thermal spraying through a metal bonding layer. A thermal barrier coating (Thermal Barrier Coating, TBC) is formed by laminating ceramic layers made of the above material to protect the refractory metal substrate from high temperatures. Comparison material ZrO ₂ system as the ceramic layer, in particular Y ₂ O ₃ in partially stabilized or fully stabilized a ZrO ₂ YSZ (yttria-stabilized zirconia) is a relatively low thermal conductivity in the ceramic material It is often used because of its high coefficient of thermal expansion.

  Depending on the type of gas turbine, it is considered that the inlet temperature of the turbine rises to a temperature exceeding 1500 ° C. When a moving blade or stationary blade of a gas turbine is covered with a thermal barrier coating provided with the ceramic layer made of YSZ, a part of the ceramic layer is operated during the operation of the gas turbine under severe operating conditions exceeding 1500 ° C. May peel off and heat resistance may be impaired. In recent years, gas turbines with higher thermal efficiency have been developed due to environmental measures, and it is considered that the inlet temperature of the turbine reaches 1600 ° C to 1700 ° C, and the surface temperature of the turbine blades is as high as 1300 ° C. It is expected to be. Accordingly, the thermal barrier coating is required to have higher heat resistance and thermal barrier properties.

The problem of peeling of the ceramic layer made of YSZ is due to insufficient crystal stability of YSZ in a high temperature environment and insufficient durability against a large thermal stress. Therefore, Yb ₂ O ₃ -added ZrO ₂ (Patent Document 1), Dy ₂ O ₃ -added ZrO ₂ (Patent Document 2), for example, are ceramic layers having excellent crystal stability in a high temperature environment and high thermal durability. , Er ₂ O ₃ -added ZrO ₂ (Patent Document 3), SmYbZrO ₇ (Patent Document 4) and the like have been developed.

  As disclosed in Patent Document 5, the ceramic layer is generally formed by thermal spraying using particles having an average particle diameter of 10 to 100 μm.

JP 2003-160852 A (Claim 1, paragraphs [0006], [0027] to [0030]) JP 2001-348655 A (claims 4 and 5, paragraphs [0010] to [0011], [0015]) JP2003-129210A (Claim 1, paragraphs [0013] and [0015]) JP 2007-270245 A (Claim 2, paragraphs [0028] to [0029] JP 2005-105417 A (Claim 2, paragraph [0063])

  By the way, the thermal spray powder having a desired particle diameter is generally obtained by performing classification work by sieving in the final process. In such a method for producing a thermal spray powder, the production efficiency is lowered due to an increase in production time, and the production cost is increased.

  In view of the above, the present invention has been made to solve the above-described problems, and is capable of producing a thermal spray powder capable of efficiently producing a powder having a desired particle diameter by a relatively simple operation. It is an object to provide a method, a turbine component and a gas turbine.

The manufacturing method of the thermal spray powder which concerns on 1st invention which solves the subject mentioned above,
A method for producing a thermal spraying powder that forms a ceramic layer laminated via a metal bonding layer on a heat-resistant alloy substrate constituting a turbine member,
The solid content concentration of the slurry formed by mixing the raw material of sprayed powder and water and the dispersant is adjusted to 70 wt% or more and 86 wt% or less,
Supplying the slurry to a disk-shaped atomizer of a spray dryer;
Adjusting the rotation speed of the atomizer, the protrusion speed at which the slurry protrudes from the atomizer is set to 42 m / second or more and 110 m / second or less,
The slurry a spray powder body formed by drying in the spray dryer, which was heat-treated cumulative particle size distribution 10% particle size and wherein the resulting Ru <br/> that the 150μm or less of the thermal spray powder than 30μm .

The turbine member according to the second invention for solving the above-described problem is
Characterized in that it comprises a thermal barrier coating having a ceramic layer formed by thermal spraying powder was produced by the method of thermal spraying powder according to the first invention.

A gas turbine according to a third invention for solving the above-described problem is as follows.
A turbine member according to the second invention is provided.

  According to the present invention, the adjustment of the solid content concentration of the slurry and the adjustment of the rotation speed of the atomizer are relatively simple operations, and it is not necessary to carry out the classification operation. Can be obtained efficiently.

1 is a cross-sectional view of a turbine member with a thermal barrier coating. It is a figure which shows the flow of the manufacturing method of the thermal spray powder which concerns on one Embodiment of this invention. It is the schematic which shows an example of the spray-drying apparatus used with the manufacturing method of thermal spraying powder. It is explanatory drawing of the atomizer which a spray-drying apparatus comprises, Comprising: The plane is shown to Fig.4 (a), and the side is shown to FIG.4 (b). It is a graph which shows the relationship between the solid content density | concentration of a slurry used with the manufacturing method of thermal spraying powder, and a recovery rate. It is a graph which shows the relationship between the protrusion speed from the atomizer of the slurry used with the manufacturing method of thermal spraying powder, and a recovery rate.

  An embodiment of a method for producing a thermal spray powder according to the present invention will be specifically described with reference to FIGS.

  As shown in FIG. 1, the thermal barrier coating formed by the thermal spray powder obtained by the thermal spray powder manufacturing method according to the present embodiment is a heat-resistant alloy base material (base material) 1 that constitutes a moving blade or the like of a gas turbine. Further, a metal bonding layer 2 excellent in corrosion resistance and oxidation resistance is laminated, and a ceramic layer 3 excellent in strength and toughness is further laminated thereon.

  The metal bonding layer 2 has a function of reducing thermal stress by reducing the difference in thermal expansion coefficient between the heat resistant alloy substrate 1 and the ceramic layer 3. Prevents peeling. The metal bonding layer 2 is composed of an MCrAlY alloy (M is a metal element such as Ni, Co, Fe, or a combination of two or more of them) as in the conventional case.

The ceramic layer 3 is composed of YbSZ (Ytterbia stabilized zirconia), YSZ (Yttria stabilized zirconia), SmYbZr ₂ O ₇ , DySZ (Dysprusia stabilized zirconia), ErSZ (Elvia stabilized zirconia), or the like.

  The metal bonding layer 2 is formed by atmospheric pressure plasma spraying, high-speed flame spraying, low pressure plasma spraying, or electron beam physical vapor deposition. The ceramic layer 3 is formed by atmospheric pressure plasma spraying. The thermal spraying powder (thermal spraying particles) used in the atmospheric pressure plasma spraying method has a particle size distribution in which the 10% cumulative particle size is 30 μm or more and 150 μm or less.

  The thermal spray powder having the particle size distribution described above is manufactured by the procedure shown in FIG. As shown in FIG. 2, first, various raw materials (raw material of the thermal spray powder) constituting the thermal spray powder are weighed so as to have a target composition according to various methods at the time of slurry preparation (step S1). Subsequently, a slurry (a mixture of powder, water, and a dispersing agent) is prepared by any one of kneading (solid phase mixing), coprecipitation method, and melting method using the various raw materials weighed in step S1. The solid content concentration of the slurry is adjusted to be 60% by weight to 86% by weight, preferably 70% by weight to 86% by weight, and more preferably 80% by weight to 86% by weight. The solid content concentration is expressed as a percentage by weight of the powder in the slurry (powder, water, and dispersant).

  Kneading is a method in which the powder, dispersant, pure water, and balls weighed in step S1 are put into a pot (container) and kneaded for 1 hour or more in a ball mill to produce a uniform slurry (step S2-1). ).

In the coprecipitation method, a neutralizer such as ammonia is added to the metal salt solution weighed in step S1 to form a precipitate, which is heat treated and then pulverized to obtain a powder. For example, when 8% by weight of Y ₂ O ₃ stabilized zirconia powder is obtained by a coprecipitation method, ammonia water is added to a YCl ₃ and ZrOCl ₂ solution (acidic) to make it neutral. At this time, a precipitate (Zr, Y) OH is formed. The precipitate is collected by filtration, heat-treated and pulverized to obtain a powder. Similar to the kneading method, this is a method of preparing a slurry by mixing a dispersant and pure water (step S2-2).

In the melting method, the powder weighed in step S1 is mixed, melted by arc discharge, and then cooled to produce an ingot. For example, when 8% by weight of Y ₂ O ₃ stabilized zirconia powder is obtained by a melting method, a powder obtained by mixing 8% by weight of Y ₂ O ₃ and 92% by weight of ZrO ₂ is melted by arc discharge. Then, the YSZ ingot is manufactured by cooling. And it is the method of grind | pulverizing an ingot and mixing a dispersing agent and a pure water like a kneading method, and producing a slurry (step S2-3).

  A thermal spray powder body is prepared by spray drying using the slurry obtained in steps S2-1, S2-2, and S2-3 (step S3).

  Here, a spray drying apparatus used for spray drying will be described with reference to FIG. As shown in FIG. 3, the spray drying apparatus 10 includes a drying chamber 11, a gas supply pipe 17, a gas discharge pipe 19, and a collector 21. The gas supply pipe 17 is provided in communication with the vicinity of the ceiling in the side wall of the drying chamber 11. Thereby, the gas 16 is supplied into the drying chamber 11 from outside the system. The gas discharge pipe 19 is provided in communication with the substantially central portion of the side wall of the drying chamber 11. Thereby, the gas 18 swirled in the drying chamber 11 is discharged out of the system. The collector 21 is provided in connection with a communication pipe 20 that communicates with a substantially central portion of the bottom of the drying chamber 11. Further, an atomizer 12, which will be described later in detail, is provided inside the drying chamber 11, and a swirling flow around the central portion of the drying chamber 11 is generated in the drying chamber 11 by the atomizer 12. Thus, when the slurry 13 protrudes from the atomizer 12, the slurry 13 descends while swirling with the gas 18 swirling in the drying chamber 11. At this time, the moisture of the slurry 13 is dried, and the sprayed powder body 22 is granulated. Then, the thermal spray powder main body 22 accumulates in the collector 21. As the drying chamber 11, the diameter D 1 is 1 m or more, the height H 1 from the ceiling portion of the drying chamber 11 to the bottom plate portion of the collector 21 is about several m to several tens m, and the gas is supplied from the gas supply pipe 17. The height H2 to the discharge pipe 19 is about 1 / 1.5-1 1/4 of H1.

  An atomizer 12 is provided at a substantially central portion of the ceiling of the drying chamber 11, and the atomizer 12 is provided with a slurry supply pipe 14 for supplying the slurry 13 produced in the steps described above. A pump 15 for feeding the slurry is provided in the middle of the slurry supply pipe 14.

  As shown in FIGS. 4A and 4B, the atomizer 12 has a disk shape, and a plurality of vertical plates 12a are provided in the vicinity of the contour portion of the ceiling plate and the bottom plate provided opposite to the ceiling plate. They are provided adjacent to each other at intervals (slits) 12b. Examples of the atomizer 12 include those having a diameter d1 of 50 mm or more and 150 mm or less, preferably 50 mm, and a height h1 of 5 mm to 20 mm, preferably 10 mm. The atomizer 12 is supplied with the slurry 13 through a supply port (not shown). The atomizer 12 is controlled by a control device (not shown) so that the rotation speed thereof, in other words, the protruding speed of the slurry 13 from the atomizer 12 is 30 m / second or more and 110 m / second or less, preferably 42 m / second or more. . As a result, the slurry 13 protrudes from the atomizer 12 and descends while swirling in the drying chamber 11, and in the collector 21 through the communication pipe 20, the accumulated particle size of 10% is 30 μm or more and 150 μm or less. A thermal spray powder body 22 having a distribution is collected. And the collected thermal spraying powder main body 22 is put in a sheath, put into a furnace with a thickness of 5 cm or less, and heat-treated at 1300 to 1600 ° C. for 1 to 10 hours. Thereby, solid melting is performed simultaneously with sintering. Since it becomes a soft lump by heat treatment, the lump is cracked and a sprayed powder is obtained by gently tapping with a pestle in a mortar. Even if this operation is performed, the thermal spray powder has a particle size distribution with an accumulated particle size of 10% and a particle size of 30 μm or more and 150 μm or less, and the powder is not pulverized to reduce the particle size.

  Therefore, according to the manufacturing method of the thermal spraying powder concerning this embodiment, the solid content concentration of the slurry 13 which mixes the raw material of spraying powder, water, and a dispersing agent is adjusted to 60 to 86 weight%, and a slurry is obtained. 13 is supplied to the disk-shaped atomizer 12 of the spray drying apparatus 10, the rotation speed of the atomizer 12 is adjusted, and the protruding speed at which the slurry 13 protrudes from the atomizer 12 is set to 30 m / second or more and 110 m / second or less. It is dried in the spray dryer 10 to form a thermal spray powder body 22, which is sintered, and a thermal spray powder having a particle size distribution in which the accumulated particle size 10% particle size becomes 30 μm or more and 150 μm or less, that is, a desired particle size. Thermal spray powder can be obtained. Therefore, it is not necessary to perform classification work, and the spray-dried apparatus 10 can efficiently obtain a sprayed powder having a desired particle size. Moreover, adjustment of the solid content concentration of the slurry 13 and adjustment of the rotation speed of the atomizer 12 are relatively simple operations.

  Although the confirmation test performed in order to confirm the effect of the manufacturing method of the thermal spraying powder concerning this invention is demonstrated below, this invention is not limited only to the confirmation test demonstrated below.

[Verification test 1]
In this test, an evaluation test was conducted on the relationship between the solid content concentration wt% (% by weight) of the slurry and the recovery rate when the protruding speed of the slurry from the atomizer was 63 m / second (the rotating speed of the atomizer was 12000 rpm). went. The evaluation test results are shown in FIG.

  Therefore, the recovery rate is 50% or more by adjusting the solid content concentration to 60 wt% or more and 86 wt% or less, and preferably the recovery rate is 70% by adjusting the solid content concentration to 70 wt% or more and 86 wt% or less. Thus, it was found that the thermal spray powder can be efficiently produced. That is, it was found that a thermal spray powder having a desired particle size distribution can be obtained by adjusting the solid content concentration of the slurry to a predetermined range. Note that if the solid content concentration of the slurry is higher than 86 wt%, the slurry cannot be properly supplied to the atomizer, so this is set as the upper limit.

[Confirmation test 2]
In this test, the relationship between the slurry protrusion speed (atomizer rotation speed) and the recovery rate when the solid content concentration of the slurry is 85 wt% (weight%) and the atomizer diameter is 50 mm was evaluated. A test was conducted. The evaluation test results are shown in FIG. The relationship between the slurry protrusion speed from the atomizer shown in FIG. 6 and the rotation speed (feed speed) of the atomizer is as shown in Table 1.

  Therefore, by adjusting the rotation speed of the atomizer so that the protruding speed of the slurry from the atomizer is 30 m / second or more and 110 m / second or less, the recovery rate is 10% or more, and preferably the rotation speed of the atomizer is adjusted. The recovery rate becomes 70% or more by setting the slurry protruding speed from the atomizer to 42 m / second or more and 110 m / second or less, and more preferably, the rotation speed of the atomizer is adjusted to adjust the slurry protruding speed from the atomizer to 63 m / second. It was found that the recovery rate was 90% or more by making the flow rate / second or more and 110 m / second or less, and the sprayed powder could be produced efficiently. That is, it was found that a sprayed powder having a desired particle size distribution can be obtained by adjusting the rotation speed of the atomizer so that the protruding speed of the slurry from the atomizer is within a predetermined range. Note that when the rotation speed of the atomizer is adjusted so that the protruding speed of the slurry from the atomizer is higher than 110 m / sec, the slurry protruding from the atomizer becomes small particles. When the protruding speed of the slurry from the atomizer is made slower than 30 m / sec, it becomes easy to adhere to the side wall of the drying chamber. As a result, the recovery rate of particles having an integrated particle size of 10% and a particle size of 30 μm or more and 150 μm or less decreases. Therefore, these are set as the upper limit value and the lower limit value, respectively.

  The thermal barrier coating having the above-described configuration is useful when applied to high-temperature parts such as a moving blade, a stationary blade, a split ring, and a combustor of an industrial gas turbine. Further, the present invention can be applied not only to industrial gas turbines but also to thermal barrier coatings for high-temperature parts of engines such as automobiles and jet aircraft.

  The thermal spray powder manufacturing method, turbine member, and gas turbine according to the present invention are relatively simple operations in which the adjustment of the solid content concentration of the slurry and the rotation speed of the atomizer itself are relatively simple, and there is no need to perform a classification operation. A spray-drying apparatus can efficiently obtain a thermal spray powder having a desired particle size, which is useful for industries that manufacture high-temperature parts such as gas turbines.

DESCRIPTION OF SYMBOLS 1 Heat resistant alloy base material 2 Metal bonding layer 3 Ceramic layer 10 Spray drying apparatus 11 Drying chamber 12 Atomizer 13 Slurry 14 Slurry supply pipe 15 Pump 16 Gas 17 Gas supply pipe 18 Swiveled gas 19 Gas discharge pipe 20 Communication pipe 21 Collection Container 22 Sprayed powder body

Claims (3)

A method for producing a thermal spraying powder that forms a ceramic layer laminated via a metal bonding layer on a heat-resistant alloy substrate constituting a turbine member,
The solid content concentration of the slurry formed by mixing the raw material of sprayed powder and water and the dispersant is adjusted to 70 wt% or more and 86 wt% or less,
Supplying the slurry to a disk-shaped atomizer of a spray dryer;
Adjusting the rotation speed of the atomizer, the protrusion speed at which the slurry protrudes from the atomizer is set to 42 m / second or more and 110 m / second or less,
The slurry a spray powder body formed by drying in the spray dryer, which was heat-treated cumulative particle size distribution 10% particle size and wherein the resulting Ru <br/> that the 150μm or less of the thermal spray powder than 30μm Manufacturing method of thermal spraying powder. A turbine member comprising a thermal barrier coating having a ceramic layer formed of a thermal spray powder obtained by the thermal spray powder manufacturing method according to claim 1 . A gas turbine comprising the turbine member according to claim 2 .

Images