JP5582910B2 - Thermal barrier coating construction method - Google Patents

Description

  The present invention relates to a method for applying a thermal barrier coating, which is devised so that a thermal barrier coating layer having good durability can be formed on the surface of a sprayed object having a complicated shape.

  In the gas turbine, in order to improve the efficiency, the temperature of the gas used is set high. A blade exposed to such a high-temperature gas is provided with a thermal barrier coating (TBC) in order to improve heat resistance. TBC is obtained by coating the surface of a blade, which is a sprayed object, with a thermal spray material having a low thermal conductivity (for example, a ceramic material having a low thermal conductivity) by thermal spraying.

  Here, a general configuration of the thermal barrier coating layer will be described with reference to FIG. As shown in the figure, an undercoat 2 is coated on a base material 1, and a topcoat 3 is coated on the undercoat 2 and TBC is applied.

The base material 1 is a blade of a gas turbine, for example, and is made of a material having excellent high temperature strength such as a Ni-base superalloy.
The undercoat 2 is formed by spraying an MCrAlY layer mainly containing an MCrAlY alloy (where M represents at least one element of Co and Ni) by LPSP (low pressure plasma spraying) or HVOF (high-speed flame spraying). Method)) is applied to the substrate 1 and laminated as a metal bonding layer. The undercoat 2 has a function of corrosion resistance to the substrate 1 and a function as a binder between the base material 1 and the topcoat 3.

The topcoat 3 is a partially stabilized zirconia obtained by partially stabilizing YSZ (Y ₂ O ₃ as an additive) on the undercoat (MCrAlY layer) 2 by spraying (APS: atmospheric pressure plasma spraying method). ) Are laminated to form a ceramic layer. The top coat layer 3 fulfills a heat shielding function to the substrate 1.

As the material of the topcoat 3, In addition to the above SmYbZr also _{2 O 7, YbSZ (Yb 2} O 3 moiety in addition stabilized partially stabilized zirconia: addition ratio of Yb ₂ O ₃ is more than 0.01 wt% 17 0.000% or less), etc., which are superior to YSZ in heat shielding properties and high-temperature phase stability.
As the coating structure of the topcoat material, a porous structure (porosity: 1% or more and 30% or less) excellent in heat-shielding properties, and a vertical crack structure (5% or more of the thickness of the topcoat layer in the thickness direction) excellent in durability And the like, which have vertical cracks at intervals of 100% or less and the number of vertical cracks per unit length (1 mm) in the cross section of the layer is 1 or more and 10 or less.

  In order to apply TBC to a sprayed object, generally, a spray gun that performs plasma spraying is attached to the tip of a multi-axis robot, and the multi-axis robot is driven to scan and move the spray gun while spraying from the spray gun. Thermal spraying is performed by spraying a thermally sprayed material on an object.

JP2009-209440

By the way, a thermal spray material that is heated and melted from a spray gun is sprayed onto a three-dimensional curved surface member such as a turbine blade (moving blade, stationary blade) by an atmospheric pressure plasma spraying method (APS) to form a top coat. In some cases, even if the construction conditions determined to have good performance at the test piece level are used as they are, the top coat structure, durability, and poor film formation efficiency may be created.
When such a defect is applied to parts such as turbine blades having a complicated curved surface compared to a simple-shaped test piece, it is necessary to devise the robot program used during thermal spraying, and this contrivance is insufficient. Furthermore, this occurs because the spray angle or spray distance is out of the proper range.

  Here, the “spraying angle θ” will be described. As shown in FIG. 8, when the sprayed material (topcoat material) 12 heated and melted from the spray gun 11 is sprayed (sprayed) on the sprayed object 13, the sprayed target is sprayed. It refers to the angle formed by the tangential plane S at the spraying point P, which is the position to which the thermal spray material 12 is sprayed, on the surface of the object 13 and the spraying direction (spraying direction) of the thermal spray material 12.

  If the above-mentioned spraying angle θ is poor, that is, if the spraying angle θ is a small angle with respect to 90 °, the durability of the topcoat may be lowered and the film forming efficiency may be lowered.

  FIG. 9 is a characteristic diagram showing the relationship between the thermal spraying angle θ and the relative thermal cycle life. If the thermal spraying angle θ is in the range of 90 ° to 70 °, the durability is high, but the thermal spraying angle θ is less than 70 °. As a result, the inventors have found that the durability tends to decrease.

When a film having a good spray angle is to be formed on the sprayed object of the three-dimensional curved surface member,
A method of scanning and moving the spray gun is desirable so that the movement trajectory of the spray point P is formed along the direction in which the curvature change is small on the surface of the sprayed object. This is because the speed of the robot during thermal spraying is relatively fast compared to other processes such as welding, and the articulated robot scans in a direction in which the curvature changes extremely (for example, longitudinally like a wing in Fig. 2). If you try to maintain the gun angle at 90 ° to the tangent plane of the spray point (in other words, move the R part of the leading edge horizontally) ), The more complicated the surface, the more control is required to move many joints at the same time, and the acceleration of the motors of each joint is superimposed, which tends to cause incompatibility that the spray point does not move at the set speed. . Such a change in speed is a problem because it is directly related to a change in film thickness. This point can be solved to some extent by improving the performance of the robot or optimizing the programming, but relatively advanced technology and time are required. Moving the gun along the direction of less curvature change will increase the stability of construction.
However, when there is a surface orthogonal to the scanning movement direction, there is a problem that it is difficult to implement the surface (orthogonal surface).

For example, as shown in FIG. 10, when spraying material 12 is sprayed on the surface of sprayed object 13 while scanning and spraying gun 11 is moved up and down, the spray angle of surface α of sprayed object 13 is 90 °. However, the thermal spray angle becomes extremely small on the surface β orthogonal to the surface α, and the durability and film formation efficiency are greatly reduced.
Further, on the surface γ, the spraying angle is close to 90 °, but since the spraying distance (distance from the spraying gun 11 to the surface of the object to be sprayed) is short, the film thickness of the formed top coat becomes too thick. May cause a problem that the film peels off.

  In view of the above prior art, the present invention is capable of forming a thermal barrier coating layer having good durability on the surface of the sprayed object, and is a sprayed object having a complicated surface shape such as a three-dimensional curved surface member. It is another object of the present invention to provide a thermal barrier coating method that can form a thermal barrier coating layer with good durability.

The configuration of the present invention for solving the above problems is as follows.
A spraying material is sprayed from a spray gun on a sprayed object having a main part having a surface to be coated and a cross member having a crossing surface intersecting the surface to be coated of the main part, In the thermal barrier coating construction method for forming the thermal barrier coating layer on the surface to be coated and on the intersecting surface,
In the state where the spraying material sprayed from the spray gun is disposed with the crossing member and the masking member for preventing the spraying from being performed on the crossing surface, the spraying angle is set in the range of 90 ° to 70 ° from the spray gun. Spraying a thermal spray material on the surface to be coated of the main part, and scanning and moving the thermal spray gun so that the movement trajectory of the thermal spray point is in a direction in which the curvature change is small in the surface to be coated;
And a step of scanning and moving the spray gun while spraying a spray material from the spray gun to the crossing surface of the cross member with a spray angle of 90 ° to 70 °.

The configuration of the present invention is as follows.
A spraying material is sprayed from a spray gun to a blade of a gas turbine having a blade portion and a cross member having a crossing surface intersecting the blade surface of the blade portion, and the blade surface and the crossing In the thermal barrier coating method for forming the thermal barrier coating layer on the surface,
In a state where a spraying material sprayed from the spray gun is disposed on the cross member and the crossing surface to prevent spraying, a spray angle is set to 90 ° to 70 ° from the spray gun to the wing portion. Spraying the spray material onto the blade surface of the blade, and scanning and moving the spray gun so that the movement locus of the spray point is in a direction connecting the tip side of the blade surface and the blade root side;
And a step of scanning and moving the spray gun while spraying a spray material from the spray gun to the crossing surface of the cross member with a spray angle of 90 ° to 70 °.

The configuration of the present invention is as follows.
A thermal spray material from a spray gun to a moving blade of a gas turbine having a blade portion and a platform portion having a platform surface intersecting the blade surface of the blade portion and a platform end surface intersecting the platform surface. In the thermal barrier coating method for forming a thermal barrier coating layer on the blade surface and on the platform surface and the platform end surface by spraying
In a state where a spraying material sprayed from the spraying gun is disposed on the platform part and the masking member for preventing spraying on the platform surface, the spraying angle is set to 90 ° to 70 ° from the spraying gun to the wing part. Spraying the spray material onto the blade surface of the blade, and scanning and moving the spray gun so that the movement locus of the spray point is in a direction connecting the tip side of the blade surface and the blade root side;
A step of scanning and moving the spray gun while spraying a spray material from the spray gun to the platform surface of the platform portion with a spray angle in a range of 90 ° to 70 °;
And a step of scanning and moving the spray gun while spraying a spray material from the spray gun to the platform end surface of the platform portion with a spray angle of 90 ° to 70 °.

According to the present invention, the thermal barrier coating is separately applied to the blade surface (main surface) and the platform surface (crossing surface), and the spray angle is set to 90 ° to 70 °. A thermal coating layer can be formed.
Further, when spraying the blade surface, since the spraying to the platform portion is blocked using the masking member, unnecessary spraying can be prevented.

The perspective view which shows the moving blade of a gas turbine. The perspective view which shows the process of forming a thermal-insulation coating layer in the blade surface of a wing | blade part. The side view which shows the process of forming a thermal-insulation coating layer in the blade surface of a wing | blade part. The perspective view which shows the process of forming a thermal-insulation coating layer in the platform surface of a platform part. The side view which shows the process of forming a thermal-insulation coating layer in the platform surface of a platform part. The side view which shows the process of forming a thermal-insulation coating layer in the platform end surface of a platform part. Sectional drawing which shows the structure of a thermal-insulation coating layer. Explanatory drawing which shows a thermal spray angle. The characteristic view which shows the relationship between a thermal spray angle and a relative thermal cycle life (durability). The block diagram which shows an example of the conventional thermal barrier coating construction method.

  Hereinafter, embodiments of the present invention will be described in detail based on examples.

  As Example 1 of the present invention, a method for applying a thermal barrier coating to a moving blade of a gas turbine will be described.

First, a moving blade 50 of a gas turbine will be described with reference to FIG. As shown in the figure, the moving blade 50 has a blade portion 51 that forms the blade, a platform portion 52 that is joined to the base side of the blade portion 51, and a shank portion 53 that is positioned below the platform portion 52. doing.
The wing surface of the wing portion 51 includes a wing belly surface, a wing leading edge surface, a wing back surface, and a wing trailing edge surface, and has a complicated shape that is generally a teardrop shape.

  In such a moving blade 50, heat insulation is performed with respect to the blade surface of the blade portion 51, the blade top portion (chip portion) 51 a, the platform surface (upper surface) 52 a of the platform portion 52, and the platform end surface 52 b of the platform portion 52. Apply coating.

  In this embodiment, a step of forming a thermal barrier coating layer on the blade surface of the blade portion 51, a step of forming a thermal barrier coating layer on the platform surface 52a of the platform portion 52, and the platform end surface 52b of the platform portion 52 The thermal barrier coating is applied by atmospheric pressure plasma spraying (APS) separately from the step of forming the thermal barrier coating layer.

  That is, the thermal barrier coating is applied to the wing surface (coating surface) of the wing portion (main portion) 51 and the platform surface (cross member) 52 of the platform portion (cross member) 52 orthogonal to (intersects) the wing surface. The thermal barrier coating and the thermal barrier coating on the platform end surface 52b orthogonal to (intersect) the platform surface 52a are separately performed.

First, a process of forming a thermal barrier coating layer on the blade surface of the blade portion 51 will be described with reference to FIGS.
As shown in both figures, the plate-shaped masking member 20 is arranged in a state of facing the platform end surface 52b of the platform portion 52. The masking member 20 not only faces the platform end surface 52b, but also the upper edge of the masking member 20 from a position where the blade surface of the wing portion 51 and the platform surface 52a intersect (the root portion of the wing portion 51). Is also located above (the tip side of the wing 51).

In FIG. 2, ladder-shaped lines indicate the scanning movement path of the spray gun 11.
More specifically, the movement trajectory of the position (spray point P) at which the thermally melted sprayed material 12 sprayed from the spray gun 11 is sprayed onto the blade surface of the blade portion is the longitudinal direction of the blade surface (the tip side of the blade surface and The spray gun 11 is scanned and moved so as to be in the direction connecting the blade root side, and after this vertical scanning movement, a predetermined pitch in the horizontal direction of the blade surface (direction perpendicular to the vertical direction) is obtained. The operation of successively moving the spray gun 11 in the vertical direction of the blade surface after shifting it by only one shift is performed.
The thermal spray gun 11 is attached to the tip of a multi-axis robot (not shown), and the multi-axis robot is driven to scan and move the thermal spray gun 11 along the ladder-shaped scanning line.

  When the spraying material 12 heated and melted is sprayed from the spraying gun 11 while the spraying gun 11 is scanned and moved in the longitudinal direction of the blade surface, the spraying material 12 is sprayed on the blade surface to form a top coat. At this time, the direction of the movement trajectory of the spray point (P) is the longitudinal direction of the blade surface, that is, the direction in which the curvature change is small in the blade surface. Moreover, the direction of the spray gun 11 is adjusted so that the spray angle θ is approximately 90 °.

  Thus, since the direction of the movement trajectory of the spraying point (P) is set to a direction in which the curvature of the blade surface is less changed and the spraying angle θ is approximately 90 °, a durable top coat is provided. Can be formed.

  As the spray angle θ, an angle in the range of 90 ° to 70 ° can be arbitrarily adopted. Further, when the spraying angle θ is set to “approximately 90 °”, the orientation of the spraying gun 11 is adjusted and controlled so that the spraying angle θ becomes 90 °. However, there is a certain amount of control error and the control error deviates from 90 °. This means an angular range that allows this.

  In the state where the thermal spray gun 11 is located at the lower position, the thermal spray material 12 sprayed from the thermal spray gun 11 is blocked by the masking member 20 and adheres to the platform surface 52a and the platform end surface 52b of the platform portion 52. There is nothing. Therefore, when the blade surface is sprayed, it is possible to prevent the platform surface 52a and the platform end surface 52b from being sprayed carelessly.

  2 and 3 show an example in which a thermal barrier coating is applied to the blade belly surface of the wing portion 51. However, when the thermal barrier coating is applied to the blade leading edge surface, blade back surface, and blade trailing edge surface. Do the same.

  Next, a process of forming a thermal barrier coating layer on the platform surface 52a of the platform 52 will be described with reference to FIGS.

  When the thermal barrier coating is applied to the platform surface 52a, the thermal spray gun 11 is scanned and moved in a state where the thermal spray angle θ is 70 ° to 90 °. In this case, the scanning movement path of the thermal spray gun 11 is a path that moves along a ladder-shaped scanning line shown in FIG.

  Thus, since the spraying angle θ is set to 70 ° to 90 °, a durable top coat can be formed.

  4 and 5 show an example in which a thermal barrier coating is applied to a surface of the platform surface 52a that is orthogonal to the blade abdominal surface. Of the platform surface 52a, the blade leading edge surface, The same is applied to the case where the thermal barrier coating is applied to the surfaces orthogonal to the blade back surface and the blade trailing edge surface.

  Next, a process of forming a thermal barrier coating layer on the platform end surface 52b of the platform 52 will be described with reference to FIG.

  As shown in FIG. 6, when the thermal barrier coating is applied to the platform end surface 52b, the thermal spray gun 11 is scanned and moved in a state where the thermal spray angle θ is 70 ° to 90 °. In this case, the scanning movement path of the spray gun 11 is a path that moves along the ladder-shaped scanning line.

  Thus, since the spraying angle θ is set to 70 ° to 90 °, a durable top coat can be formed.

  FIG. 6 shows an example in which the thermal barrier coating is applied to one of the platform end surfaces 52a. However, when the thermal barrier coating is applied to the remaining three surfaces, Do the same.

Although Example 1 mentioned above has shown the example which performs thermal-insulation coating construction to the moving blade 50 of a gas turbine, it is the same also about the stationary blade of a gas turbine, and other 3D curved surface members, Thermal barrier coating can be applied.
That is, when there are intersecting (orthogonal) surfaces, each surface is individually subjected to thermal barrier coating, and the thermal barrier coating layer is formed with a thermal spray angle θ of 70 ° to 90 °. And when it will be in the situation where thermal spraying is carried out to an unnecessary part, a masking member is used and unnecessary thermal spraying is interrupted | blocked.

  The present invention can be applied not only to blades (moving blades and stationary blades) of gas turbines but also to various members having a three-dimensional curved surface that requires thermal barrier coating.

DESCRIPTION OF SYMBOLS 1 Base material 2 Undercoat 3 Topcoat 11 Thermal spray gun 12 Thermal spray material 13 Sprayed object 20 Masking member 50 Moving blade 51 Blade part 52 Platform part 52a Platform surface 52b Platform end surface 53 Shank part P Thermal spray point S Tangent plane θ Thermal spray angle

Claims (3)

A spraying material is sprayed from a spray gun on a sprayed object having a main part having a surface to be coated and a cross member having a crossing surface intersecting the surface to be coated of the main part, In the thermal barrier coating construction method for forming the thermal barrier coating layer on the surface to be coated and on the intersecting surface,
In the state where the spraying material sprayed from the spray gun is disposed with the crossing member and the masking member for preventing the spraying from being performed on the crossing surface, the spraying angle is set in the range of 90 ° to 70 ° from the spray gun. Spraying a thermal spray material on the surface to be coated of the main part, and scanning and moving the thermal spray gun so that the movement trajectory of the thermal spray point is in a direction in which the curvature change is small in the surface to be coated;
A step of scanning and moving the spray gun while spraying a spray material from the spray gun to the crossing surface of the cross member with a spray angle of 90 ° to 70 °;
The thermal barrier coating construction method characterized by having. A spraying material is sprayed from a spray gun to a blade of a gas turbine having a blade portion and a cross member having a crossing surface intersecting the blade surface of the blade portion, and the blade surface and the crossing In the thermal barrier coating method for forming the thermal barrier coating layer on the surface,
In a state where a spraying material sprayed from the spray gun is disposed on the cross member and the crossing surface to prevent spraying, a spray angle is set to 90 ° to 70 ° from the spray gun to the wing portion. Spraying the spray material onto the blade surface of the blade, and scanning and moving the spray gun so that the movement locus of the spray point is in a direction connecting the tip side of the blade surface and the blade root side;
A step of scanning and moving the spray gun while spraying a spray material from the spray gun to the crossing surface of the cross member with a spray angle of 90 ° to 70 °;
The thermal barrier coating construction method characterized by having. A thermal spray material from a spray gun to a moving blade of a gas turbine having a blade portion and a platform portion having a platform surface intersecting the blade surface of the blade portion and a platform end surface intersecting the platform surface. In the thermal barrier coating method for forming a thermal barrier coating layer on the blade surface and on the platform surface and the platform end surface by spraying
In a state where a spraying material sprayed from the spraying gun is disposed on the platform part and the masking member for preventing spraying on the platform surface, the spraying angle is set to 90 ° to 70 ° from the spraying gun to the wing part. Spraying the spray material onto the blade surface of the blade, and scanning and moving the spray gun so that the movement locus of the spray point is in a direction connecting the tip side of the blade surface and the blade root side;
A step of scanning and moving the spray gun while spraying a spray material from the spray gun to the platform surface of the platform portion with a spray angle in a range of 90 ° to 70 °;
A step of scanning and moving the spray gun while spraying a spray material from the spray gun to the platform end surface of the platform portion with a spray angle of 90 ° to 70 °;
The thermal barrier coating construction method characterized by having.

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