JPH08127857A - Thermal spraying torch and thermal spraying method - Google Patents

Abstract

PURPOSE: To realize a thermal spraying torch in which the temp., atmosphere and jetting rate in a melting heat source field of thermal spraying material grains can be controlled. CONSTITUTION: As a heat stream generating device (1, 2), e.g. a plasma thermal spraying torch is used, and a cylinder 20 is deposited so as to surround the generated plasma jet. In the case the cylinder 20 is provided with a gas introducing port 13 for controlling the atmosphere in the space at the inside of the cylinder, by introducing gaseous oxygen from the same port 13, the thermal spraying material at the inside of the cylinder 20 can be melted without being reduced. Owing to the deposition of the cylinder 20, coating can be formed by using many kinds of thermal spraying materials.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal spray coating forming technique.

[0002]

2. Description of the Related Art An example of a conventional thermal spray torch, which is an apparatus for forming a thermal spray coating, and a thermal spray method using the same will be described below with reference to the drawings.

FIG. 4 is a sectional view showing the main part of a general thermal spray torch. In FIG. 4, an anode 101 made of, for example, copper and a cathode 10 made of, for example, tungsten at its tip are provided.
An arc 103 is generated between the nozzle 1 and the nozzle portion 1 of the anode 101 as a hot air flow 105 by converting the working gas 104 supplied from the rear into plasma.
Eject from 01a.

In this state, the thermal spray material particles 107 are introduced into the hot air flow 105 by the carrier gas 106 through the thermal spray material supply holes 108 and melted, and collided as liquid fine particles 109 onto the surface of the thermal spray target 110, whereby the flat particles 111a. To form a film 111 having a laminated structure.

Here, in order to form a high quality sprayed coating, it is necessary to provide a molten state and an accelerated state suitable for the sprayed material particles 107 by the hot air flow 105 and collide with the sprayed target 110.

In other words, it is necessary that the temperature and velocity of the hot air flow 105 can be optimized according to the spray material particles 107.

[0007]

However, the above-mentioned structure has the following problems.

The first problem is that when the optimum molten state of the spray material particles 107 cannot be obtained at the position of the charging hole 108,
Adjust the temperature of the hot air flow 105, or
Any of the methods of moving the position 8 according to the temperature distribution of the hot air flow 105 is adopted.

The temperature of the hot air flow 105 is adjusted under the plasma generation condition, but it is practically difficult to realize the optimum temperature corresponding to the melting point for various materials only by adjusting the temperature.

In addition, since a large temperature distribution does not occur in the hot air flow 105 in the anode 101 and the position of the charging hole 108 itself cannot be largely moved, the charging hole 108 is not changed.
Measures by moving the position of are not sufficient.

Therefore, as shown in FIG.
Distribution of the hot air flow 105 and the thermal spray material particles 107 downstream of the
It is considered that the above problems can be solved if the material supply port 112 is provided at a position determined by the melting point of the material and the thermal spray material particles 107 are charged and melted.

However, although the temperature of the generated hot air flow 105 is high in the vicinity of the generation point of the arc 103, it suddenly drops as soon as it comes out of the nozzle portion 101a.

As a result, the thermal spray material particles 107 cannot be melted even if charged through the material supply port 112,
In some cases, a film could not be formed.

The second problem is that the thermal spray material particles 107
Even if is melted satisfactorily, the thermal spray material particles 107 are affected by the ambient atmosphere, for example, an oxidation / reduction reaction, before reaching the thermal spray target 110. As a result, the film 111
May be different from the characteristics of the sprayed material particles 107 as the starting material.

A third problem is that the spray coating material 107 is made of flat particles 111a due to the nature of the method of forming the spray coating.
As a result, a film 111 is formed. At that time, of course, the film 11
1 is distorted. Depending on the material, the presence of this strain may change the characteristics.

As a fourth problem, the thermal spraying material particles 107 which have been once melted by the action of the hot air stream 105 due to the rapid temperature drop of the hot air stream 105 cannot receive the heat thereafter and can be kept in the molten state. In some cases, it solidifies before reaching the thermal spray target 110.

In such a state, the charged thermal spray material particles 107 cannot effectively contribute to film formation, resulting in a decrease in material utilization rate.

In view of the above problems, it is an object of the present invention to provide a thermal spraying torch and a thermal spraying method capable of controlling the temperature, atmosphere and injection speed of the thermal spray material as a heat source for melting the thermal spray material.

[0019]

Means for solving the above problems are as follows.

That is, the invention according to claim 1 of the present application is a thermal spray torch comprising at least a hot air flow generating means and a cylinder arranged in front of the hot air flow generating means, wherein the cylinder has a The thermal spray torch is characterized in that a thermal spray material introducing port for introducing a thermal spray material and a gas introducing port for introducing a gas are provided.

The invention according to claim 2 is at least
A step of generating a heat flow inside the cylinder arranged in front of the heat flow generating means, and a step of charging and melting the spray material into the inside of the cylinder by means of a spray material introduction port provided in the cylinder;
And a step of introducing gas into the inside of the cylinder through a gas introduction port provided in the cylinder.

[0022]

The function of this technical means is as follows.

According to the above means, the inner space of the cylinder can be used as a melting field of the particles of the sprayed material, and the temperature of the inner space of the cylinder, the atmosphere such as oxidation and reduction, and the blowing speed of the hot air flow can be easily controlled. And it can be realized widely.

Therefore, it is possible to set favorable spraying conditions even for a sensitive spraying material whose characteristics greatly change due to heat, impact, chemical reaction, etc. in a normal spraying process, and to obtain a spraying having desired characteristics. A coating can be formed and the utilization efficiency of thermal spray material particles is also improved.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A thermal spray torch according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a main part of a thermal spray torch in a thermal spray apparatus (not shown) according to an embodiment of the present invention.

An arc 3 is generated between an anode 1 made of, for example, copper and a cathode 2 made of, for example, tungsten at its tip, and a working gas 4 supplied from the rear is turned into plasma, whereby a hot air flow 5 is generated. It spouts from the nozzle part 1a of No.1.

The cylinder 20 is made of a heat-resistant and heat-insulating material such as ceramics. The heat quantity of the heat flow 5 is confined in the space inside the cylinder 20 by partitioning the space near the jetting place of the heat flow 5 and the outer space. You can

Reference numeral 13 is a gas introduction port for introducing a gas 13g into the cylinder 20, and reference numeral 12 is a spray material introduction port for introducing the spray material particles 12p into the cylinder 20 with a carrier gas 12g.

Due to the presence of the cylinder 20, the temperature of the space near the jetting place of the air flow 5 is maintained at a high temperature as compared with the case where the cylinder 20 is not present, and at the same time, the temperature decrease is very gentle.

As a result, it is possible to create a temperature field that cannot be obtained with a normal thermal spray torch without the cylinder 20, and it is possible to melt various types of thermal spray material particles.

Furthermore, since the melted thermal spray material particles 12p fly in the high temperature region inside the cylinder 20, they become an effective film without solidifying before reaching the thermal spray target 10.

The atmosphere inside the cylinder 20 can be controlled by the gas 13g introduced from the gas introduction port 13.

For example, in a normal thermal spray torch, since argon, helium, etc. are used as plasma gas, the material may be reduced and the characteristics may change greatly depending on the material. 13 g
By using oxygen or the like as the thermal spray material particles 12
The melting field of p becomes an oxidizing atmosphere, and the thermal spray material particles 12p can be melted without reducing.

In the above state, the gas existing inside the cylinder 20 is blown out from the cylinder 20 as a hot air flow 15 by thermal expansion,
At the same time, the melted thermal spray material particles 12p are also jetted toward the thermal spray target 10 to form the film 11 having a structure in which the flat particles 11a are laminated on the thermal spray target 10.

Here, depending on the material, the characteristic change may occur due to the strain generated at the time of collision with the thermal spray target 10. However, according to the configuration of the present invention, by changing the opening shape of the cylinder 20. Since the jet speed of the hot air flow 15 can be changed arbitrarily, the thermal spray material particles 12p
It is possible to optimize the collision speed of the above with the substrate 10.

From the above, it is possible to obtain the film 11 in which the initial characteristics of the spray material particles 12p are maintained by the spray torch and spray method of the present invention.

Here, in order to further enhance the effect of preventing the material characteristics of the thermal spray material particles 13p from changing, the thermal spray material introduction port 12 is provided downstream of the gas introduction port 13 with respect to the air flow 5, and the thermal spray material particles 12p are introduced. At the point, the atmosphere is well controlled.

In order to control the atmosphere inside the cylinder 20 more finely, the carrier gas 12g for introducing the thermal spray material 12p is the same as the gas 13g introduced for controlling the atmosphere inside the cylinder 20. It is possible to use different types of gas.

To further finely control the temperature distribution inside the cylinder 20, before carrying the carrier gas 12g for introducing the thermal spray material 12p and the gas 13g into the cylinder 20, it is necessary to carry out appropriate control. Heat to temperature.

FIG. 2 is a cross section of the main part of the cylinder 20 in the radial direction. As shown in FIG. 2, the gas introduction port 13 and the thermal spray material introduction port 12 are respectively provided with a hot air flow 5 in order to prevent the history of the thermal spray material particles 12p from varying depending on the position of the thermal spray material introduction port 12. A plurality of axially symmetrical arrangements may be provided so that various state quantities inside the cylinder 20 are uniform in the radial cross section.

FIG. 3 is a sectional view of the main part of the cylinder 20 in the axial direction.
In order to make the temperature change inside the cylinder 20 more gradual, as shown in FIG. 3, the wall thickness of the cylinder 20 is gradually increased from the upstream side to the downstream side of the hot air flow 5 so that the inside of the cylinder 20 is reduced. The heat is easily released in the upstream high temperature portion, and the heat is not easily released in the downstream low temperature portion.
A structure that changes in the longitudinal direction of 0 is also effective.

In the above description, the plasma spray torch is used as the means for generating the hot air flow 5, but
Of course, the same effect can be obtained when other generating means is used.

[0044]

As described above, the present invention has made it possible to form a film on various types of thermal spraying materials while maintaining the initial characteristics. As a result, the functional film was formed by the thermal spraying method.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a thermal spray torch according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part in a radial direction of a cylinder for explaining the configuration in the embodiment.

FIG. 3 is a sectional view of an essential part in the axial direction of the cylinder for explaining the configuration in the embodiment.

FIG. 4 is a sectional view of a main part of a conventional general thermal spray torch.

FIG. 5 is a sectional view of a main part of a conventional general thermal spray torch.

[Explanation of symbols]

 12 Thermal Spray Material Introducing Port 12p Thermal Spray Material Particles 13 Gas Introducing Port 13g Gas 20 Cylinder

Claims (9)

[Claims] 1. A thermal spray torch comprising at least a hot air flow generating means and a cylinder arranged in front of the hot air flow generating means, wherein the thermal spray material introduction means for introducing the thermal spray material into the cylinder. A thermal spray torch comprising a port and a gas introduction port for introducing a gas. 2. A step of at least generating a heat flow inside a cylinder arranged in front of the heat flow generating means, and a step of charging and melting the spray material into the inside of the cylinder by means of a spray material introduction port provided in the cylinder. And a step of introducing a gas into the inside of the cylinder through a gas introduction port provided in the cylinder. 3. The thermal spray torch according to claim 1, wherein a plasma thermal spray torch is used as the hot air flow generating means. 4. The thermal spray torch according to claim 1, wherein ceramic is used as the material of the cylinder. 5. The thermal spray torch according to claim 1, wherein the wall thickness of the cylinder gradually increases from the upstream side to the downstream side of the hot air flow. 6. The thermal spray torch according to claim 1, wherein the gas introduction port is disposed upstream of the thermal spray material introduction port with respect to the hot air flow. 7. The thermal spray torch according to claim 1, wherein the thermal spray material introducing port and the gas introducing port are arranged symmetrically with respect to the hot air flow. 8. The thermal spraying method according to claim 2, wherein the same gas as the gas is used as a carrier gas for introducing the thermal spray material. 9. The thermal spraying method according to claim 2, wherein the carrier gas for introducing the thermal spray material and the gas are preheated before being introduced into the inside of the cylinder.