JPH03264657A - Negative pressure-type masking device for plasma spraying - Google Patents

Abstract

PURPOSE:To make the boundary of the film formed by plasma spraying clear by forming the gas masking element for plasma spraying having a gas suction path in the shape of a horseshoe and communicating the element with a negative-pressure gas feed mechanism. CONSTITUTION:The horseshoe gas masking element 11 (11a-11d) contg. a gas suction path 21, having a gas suction port 22 along the inner surface and consisting of a hollow heat-resistant structural material is supported by the negative pressure supply supports 12a-12d connected to a gas manifold 13. The element 11 is arranged on a ceramic supporting pipe 1 held by a support 14, the supporting pipe 1 is rotated by the rotating shaft 14, a powder is thermally sprayed from a spray gun 3, and the powder is sucked from the gas suction port 22 to form a film. Consequently, the diffraction and diffusion of powder are prevented on both sides of the sprayed film formed on the supporting pipe 1, and the film having a clear boundary is formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a negative pressure masking device for plasma spraying in a solid electrolyte fuel cell, and in particular to a mechanism for preventing powder diffraction and scattering in the spraying part of a plasma spraying device. The present invention relates to a device equipped with the following.

[Prior Art 1] Among the plasma spraying methods, the reduced pressure spraying method is a method developed in recent years in which the base material to be sprayed and equipment are housed in a reduced pressure container to obtain a denser coating film.

The electrolyte membrane of a solid electrolyte fuel cell is mainly manufactured by melting ittria-stabilized zirconia powder in a DC arc plasma.

Traditional plasma spraying methods are performed in the atmosphere or in special gases. In this device, solid electrolyte fuel cell components (electrode membrane,
Fabricate an interconnector (■・C) that electrically connects the electrolyte membrane) and fuel cell element.

The structure of the solid electrolyte fuel cell manufactured in this manner is shown in FIG. In this figure, 1
is a hollow cylindrical ceramic support tube, on the outer peripheral surface of which a fuel electrode 2, a solid electrolyte 3, and an air electrode 4 are formed. Note that 5 indicates the current source, 10 indicates the entire solid electrolyte fuel cell, and Ga indicates the gap between the air electrodes 4.

One of the important points in this configuration is to secure the gap Ga shown in the figure.

In the conventional plasma spraying method, a slit 41 is formed between the spray gun 40 and the ceramic support tube 1 as shown in FIGS. 6 and 7.
The solid electrolyte fuel cell 10 having the structure shown in FIG. 5 is created by placing the shielding plate 42 provided with the solid electrolyte fuel cell 10 and shifting it in the axial direction. In addition, 6 in FIG. 7 is the fuel electrode 2 mentioned above.
．． Solid electrolyte 3. This membrane collectively refers to the air electrode 4.

[Problems to be Solved by the Invention] However, in the conventional slit method, the molten powder sprayed from the thermal spray gun 40 onto the ceramic support tube 1 passes through the slit 41.
After passing through the gap, it is diffracted and forms the gaps Ga and Gb shown in
This had the serious problem of covering the surface.

Further, in the reduced pressure thermal spraying method, since the arc plasma jet used for thermal spraying is enlarged, the molten powder is diffused in the jet in the flow direction, and the above-mentioned diffraction phenomenon becomes more pronounced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a negative pressure masking device for plasma spraying that solves the above-mentioned problems that cannot be avoided with conventional plasma spraying methods.

[Means for Solving the Problems] The invention according to claim (1) relates to a semicircular, horseshoe-shaped, or It consists of a rectangular gas masking element and a negative pressure gas supply mechanism that communicates with the gas passage of this gas masking element and supplies negative pressure.

Furthermore, the invention as set forth in claim (2) is one in which the gas masking element is provided with a rectifying air mechanism.

[Operation 1] In the invention described in claim (1) of the present invention, the negative pressure supplied from the gas suction mechanism sucks the powder that is thermally sprayed onto the ceramic support tube and is about to be diffracted from the gas masking element, thereby preventing the thermal spraying from occurring. Diffusion on both sides of the formed film is prevented and a clear boundary is formed.

Moreover, in the invention described in claim (2), the flow of the plasma gas is adjusted by the rectifying air mechanism.

[Embodiment 1] Fig. 1 is a perspective view showing an embodiment of the present invention, in which 1 is a ceramic support tube, 11a, Ilb, 11c, 11d (hereinafter, 11 will be simply used when there is no need to distinguish. The symbols are the same.) indicate gas masking elements, which are made of hollow heat-resistant structural material. These are supported by negative pressure supply supports +2a, 12b, 12c, and 12d connected to the gas manifold 13, respectively, and receive negative pressure from there. Further, 14 is a support for the ceramic support tube 1, and 15 is a rotation shaft.

Reference numeral 16 denotes a fine adjustment device, which can be moved in the axial direction by rotating an adjustment screw 16a, thereby making it possible to form a film of a desired length. Note that 17 is a moving rail, 18 is a gas supply port, and 19 is a base.

2(a), (b) and (c) are perspective views showing details of various embodiments of the gas masking element 11 of FIG. 1. FIG. Inside the gas masking element 11, a gas passage 21 is formed as shown in FIG. 2(a), and gas suction ports 22 are provided in two rows along the inner surface thereof.

Alternatively, the gas suction grooves 23 may be provided in two rows along the inner surface as shown in FIG. 2(b).

FIG. 2(C) is an example in which the negative pressure supply support 12a is provided at the bottom. The negative pressure supplied from the negative pressure supply support 12a is cooled by the gas flowing through the gas masking element 11, and is also cooled by the gas suction port 22 or the gas suction groove 2.
3 to prevent powder diffraction. The width of the opening 24 of the gas masking element 11 can be sized according to the outer diameter of the ceramic support tube 1.

In each of the above embodiments, the gas suction ports 22 and the gas suction grooves 23 are provided in two rows, but they may be provided in one or two rows.

FIG. 3 is a schematic cross-sectional view of the embodiment shown in FIG. 2(a), in which a rectifying plate 25 as a rectifying air mechanism is provided outside the gas suction port 22.

Thus, the gas masking elements 11 shown in FIGS. 2(a), (b), and (c), on the one hand, rectify the flow of sprayed particles along the wall in the flow direction, reducing diffusion. do. Further, by supplying a negative pressure, thermal spray particles that are about to spread are sucked in, thereby preventing them from spreading. The gas masking element 11 is also cooled by passing gas thereinto,
Prevented from deformation and destruction. Due to this effect, a film 31 with clear boundaries can be formed as shown in FIG.
The distance Ga between the film 1 and the film 31 is also 0.5 mm, which can improve the accuracy by one order of magnitude.

The gas masking element 11 is shown in FIGS. 2(a) to 2(c).
In addition to the horseshoe shape shown in the figure, a semicircular shape, a rectangular shape, or a shape similar to this may also be used.

[Effect of the invention 1 As explained above, the invention described in claim (11)
A semicircular, horseshoe-shaped, or rectangular gas masking element that has a gas suction passage inside and a gas suction port or gas suction groove along the inner surface, and a negative pressure that communicates with the gas passage of this gas masking element to supply negative pressure. Since it consists of a gas supply mechanism and the gap between adjacent membranes is small, it is possible to increase the number of solid electrolyte fuel cells that can be manufactured on a ceramic support tube and increase the utilization rate of the surface of the ceramic support tube. can.

In addition, the part where the solid electrolyte fuel cell elements are connected in series can be shortened, and more power can be generated.

Furthermore, interdiffusion of gases from this connection can be reduced, improving fuel utilization efficiency, and continuous production of fuel cell stacks becomes possible, greatly improving productivity.

Further, the invention as set forth in claim (2) has the advantage that highly accurate film formation can be performed because the flow of the plasma gas is adjusted by the rectified air mechanism.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG.
), (b), and (c) are all perspective views showing the general shape of the gas masking element in FIG.
), FIG. 4 is an explanatory diagram showing the shape of the film formed by the gas masking device for thermal spraying of the present invention, and FIG. 5 is a schematic diagram of a solid electrolyte fuel cell. FIG. 6 is a perspective view schematically showing a means for manufacturing a battery stack using a conventional slit method, and FIG.
This figure is a partial cross-sectional view showing the shape of a film formed by the slit method of FIG. 6. In the figure, 1 is a ceramic support tube, 2 is a fuel electrode, 3 is a solid electrolyte, 4 is an air electrode, 5 is a current lead, 6 is a membrane, 10
11a to 12d are solid electrolyte fuel cells, 11a to lid are gas masking elements, 12a to 12d are negative pressure supply supports, 13 is a gas manifold, 14 is a support, 15 is a rotating shaft, 16 is a fine adjustment device, and 22 is a gas inlet , 23 is a gas suction groove, 24
is the opening.

Claims (2)

[Claims] (1) A semicircular, horseshoe-shaped, or rectangular gas masking element that has a gas suction passage inside and a gas suction port or gas suction groove along the inner surface, and communicates with the gas passage of this gas masking element to supply negative pressure gas. A negative pressure masking device for plasma spraying, characterized in that it is equipped with a negative pressure gas supply mechanism. (2) The negative pressure masking device for plasma thermal spraying according to claim (1), wherein the gas masking element has a rectifying air mechanism for regulating the flow of plasma gas.