WO2016151826A1

WO2016151826A1 - Plasma thermal spray apparatus

Info

Publication number: WO2016151826A1
Application number: PCT/JP2015/059272
Authority: WO
Inventors: 智昭北村; 田中　誠; 秀雄石丸; 智司崎山
Original assignee: 中国電力株式会社; 国立大学法人山口大学
Priority date: 2015-03-25
Filing date: 2015-03-25
Publication date: 2016-09-29
Also published as: JP6111477B2; JPWO2016151826A1

Abstract

This plasma thermal spray apparatus comprises: a main torch for introducing a main plasma gas along a central axis, the main torch comprising a main anode having a material delivery tube for delivering a material supply gas containing a thermal spray material along the central axis; and a plurality of subtorches having a central axis that intersects the central axis of the main anode and disposed circumferentially apart from one another on a circumference around the central axis of the main anode, the subtorches comprising a subcathode. The plasma thermal spray apparatus forms a coating of the thermal spray material by: delivering the material supply gas through the material delivery tube to a plasma flame generated along the central axis of the main anode from plasma arcs formed between the main anode and the subcathodes, the main plasma gas introduced along the central axis of the main anode, and a subplasma gas introduced along the central axes of the subcathodes towards the central axis of the main anode; and melting and spraying the thermal spray material onto a base material. The plasma thermal spray apparatus is provided with supply rate control units for controlling the supply rate of the subplasma gas.

Description

Plasma spraying equipment

The present invention has a main torch having a main anode and a plurality of sub torches having sub-cathodes, and sprays a thermal spray material melted by a plasma flame formed along the central axis of the main anode onto a substrate. The present invention relates to a plasma spraying apparatus for forming a coating.

Conventionally, in a plasma spraying apparatus having a main torch having a main anode and a plurality of sub torches having sub-cathodes, a material discharge hole is provided at the center of the center axis of the main anode of the main torch, and the center of the main electrode is formed from the material discharge hole. There is known a plasma spraying apparatus that can supply a thermal spray material along an axis, efficiently melt the thermal spray material, and spray it onto a base material to form a film (see, for example, Patent Document 1).

JP 2010-110669 A

In the plasma spraying apparatus as described above, the main torch electrode is an anode whose temperature is lower than that of the cathode, and the cathode that needs to emit thermionic electrons to maintain the plasma arc is the sub torch side. Since the adhesion of the sprayed material to the main electrode side is suppressed, it is possible to provide a material discharge hole in the main electrode. That is, in the past, in order to avoid adhesion of the thermal spray material to the main electrode, the thermal spray material was supplied from a direction inclined with respect to the central axis of the main electrode where the plasma arc is formed. It became possible to supply thermal spray material along. As a result, the sprayed material can be reliably supplied to the center of the plasma flame having a higher temperature with respect to the periphery, and scattering of the sprayed material to the periphery can be suppressed. Furthermore, as a result of verification by experiment, the inventors changed the supply condition of the subplasma gas introduced along the subelectrode of the plasma spraying apparatus, which did not exist in the conventional plasma spraying apparatus, as a parameter. It became clear that the properties of the film could be controlled.
Therefore, an object of the present invention is to provide a plasma spraying apparatus capable of forming a coating film by changing supply conditions of plasma gas.

In order to achieve the above object, the plasma spraying apparatus of the present invention includes a main anode having a material feeding pipe for feeding a material supply gas containing a sprayed material along a central axis, and the main plasma along the central axis. A main torch for introducing gas and a central axis intersecting with the central axis of the main anode and arranged on a circumference centering on the central axis of the main anode and spaced apart from each other in the circumferential direction A plurality of sub-torches each having a sub-cathode, a plasma arc formed between the main anode and the sub-cathode, and the main plasma introduced along the central axis of the main anode A plasma flame formed along the central axis of the main anode by a gas and the sub-plasma gas introduced along the central axis of the sub-cathode and toward the central axis of the main anode. The material from the material feed tube In a plasma spraying apparatus in which a supply gas is fed and the sprayed material is melted and sprayed onto a substrate to form a coating of the sprayed material, the plasma spraying apparatus includes a supply amount control unit that controls a supply amount of the sub-plasma gas. It is a plasma spraying device characterized.

According to such a plasma spraying apparatus, the supply amount of the secondary plasma gas introduced toward the plasma flame formed along the central axis of the main anode and supplied along the central axis of the secondary cathode is controlled. Since the supply amount control unit is provided, the supply of the subplasma gas is controlled by controlling the supply amount of the subplasma gas acting from the direction intersecting the material supply gas when the sprayed material to be melted reaches the substrate. It is possible to form films with different amounts.

In this plasma spraying apparatus, it is preferable that the supply amount control unit controls the supply amount of the sub-plasma gas so as to change the characteristics of the film to be formed.
According to such a plasma spraying apparatus, it is possible to control the supply amount of the secondary plasma gas by the supply amount control unit to form films having different characteristics.

In such a plasma spraying apparatus, it is desirable that the characteristic of the coating is the thickness of the coating to be formed.
According to such a plasma spraying apparatus, it is possible to form coatings having different thicknesses by controlling the supply amount of the secondary plasma gas by the supply amount control unit.

In this plasma spraying apparatus, it is desirable that the supply amount control unit controls the supply amount of the secondary plasma gas to be increased as the thickness of the coating is increased.
According to such a plasma spraying apparatus, it is possible to form a thick film by increasing the supply amount of the secondary plasma gas by the supply amount control unit.

In this plasma spraying apparatus, the characteristic of the film may be the hardness of the film to be formed.
According to such a plasma spraying apparatus, it is possible to control the supply amount of the secondary plasma gas by the supply amount control unit to form films having different hardnesses.

In such a plasma spraying apparatus, it is preferable that the supply amount control unit controls the supply amount of the secondary plasma gas to be increased as the hardness of the coating is increased.
According to such a plasma spraying apparatus, it is possible to form a coating with high hardness by increasing the supply amount of the secondary plasma gas by the supply amount control unit, and by reducing the supply amount of the secondary plasma gas. It is possible to form a film with low hardness.

In this plasma spraying apparatus, a characteristic database in which the characteristic of the film and the supply amount of the sub-plasma gas are associated with each other is generated, and the supply amount control unit includes the characteristic and the characteristic of the film to be formed. It is desirable to control the supply amount of the secondary plasma gas based on a database.
According to such a plasma spraying apparatus, the supply amount control unit controls the supply amount of the secondary plasma gas based on the characteristics of the film to be formed and the characteristic database generated in advance. Easy.

In this plasma spraying apparatus, the supply amount control unit observes at least one of a particle velocity and a particle temperature of the sprayed material sprayed on the base material, and observes the observation result and the coating of the coating to be formed. It is desirable to control the supply amount of the secondary plasma gas based on the characteristics.
According to such a plasma spraying apparatus, the supply amount of the secondary plasma gas is controlled based on the observation result obtained by observing at least one of the particle velocity and the particle temperature of the sprayed material sprayed on the base material. Therefore, it is possible to form a film having desired characteristics.

In this plasma spraying apparatus, it is desirable that the plurality of sub torches be arranged uniformly in the circumferential direction.
According to such a plasma spraying apparatus, the plurality of sub-torches are arranged uniformly in the circumferential direction, so that the sub-plasma gas is supplied from the circumference centered on the central axis of the main anode. Since it acts on the gas, it is possible to cause the secondary plasma gas to act in a balanced manner.

According to the present invention, it is possible to provide a plasma spraying apparatus capable of forming a coating by changing the supply conditions of the spraying material.

1 is a diagram showing a schematic configuration of a twin cathode type plasma spraying apparatus 100 as an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA in FIG. It is an image which shows the state of the plasma flame 23 when

subplasma gas

13, 49 is sprayed from two

subtorches

2,39. It is a graph which shows the relationship between the supply amount of

subplasma gas

13,49, and the thickness of the membrane | film | coat 24 formed. It is a graph which shows the relationship between the supply amount of

subplasma gas

13,49, and the hardness of the membrane | film | coat 24 formed. 1 is a diagram showing a schematic configuration of an integrated plasma spray apparatus 101. FIG.

Hereinafter, preferred embodiments of a plasma spraying apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

First, as a plasma spraying apparatus according to the present invention, a plasma spraying apparatus including a main torch and a plurality of sub-torches, which is a composite torch type plasma spraying apparatus including a main torch and a sub-torch, will be described. Note that the composite torch type plasma spraying apparatus of the present embodiment includes, for example, one main torch and two auxiliary torches. FIG. 1 is a diagram showing a schematic configuration of a twin cathode type plasma spraying apparatus 100 as an embodiment of the present invention. In the twin cathode type plasma spraying apparatus (hereinafter referred to as plasma spraying apparatus) 100 of the present embodiment, the electrode in the main torch 1 is the main anode (anode) 3 and the electrodes in the

sub torches

2 and 39 are the sub cathode (cathode). 10 and 40.

The two

sub-torches

2 and 39 have their center axes C2 intersecting with the center axis C1 of the main anode 3 substantially at right angles, and on the circumference centering on the center axis C1 of the main anode 3, They are arranged at intervals. Since the plasma spraying apparatus 100 of the present embodiment has two sub torches 2, the two

sub torches

2 and 39 are arranged so as to face each other.

The main torch 1 includes a main anode 3, a main mantle 4 surrounding the main anode 3, an insulator 27 that insulates the main anode 3 and the main mantle 4, and the like, and is concentrically formed by the main mantle 4 and the insulator 27. Is retained.
The main anode 3 is formed of a material having excellent electrical conductivity, for example, a metal such as copper. The main anode 3 includes a material feed pipe 19 having a spray material discharge hole 19a at the center of the tip on the central axis C1.

The main mantle 4 includes an opening (nozzle portion) 4a at the tip, and a tapered portion 4b provided between the opening 4a and the insulator 27.

The insulator 27 has a main plasma gas inlet 5 through which the main plasma gas 6 is introduced, and a swirl flow forming portion 50 for the introduced main plasma gas 6. As shown in FIG. 2, the main plasma gas 6 is introduced into the gas annular chamber 51, passes through the four swirl flow forming holes 52, and passes through the inner wall 53 (between the inner wall 53 and the main anode 3) of the insulator 27. It flows toward the opening 4a of the main mantle 4 so as to turn in the space. The swirl flow forming holes 52 may be arranged in a single number or in a plurality, and in the case where a plurality of the swirl flow holes 52 are arranged, the swirl flow forming holes 52 should be evenly arranged around the central axis C1. Is preferred.

The two

sub-torches

2 and 39 have the same structure, and the sub-cathodes (sub-torch activation electrodes) 10 and 40, sub-mantles 11 and 41 surrounding the sub-cathodes 10 and 40, and sub-cathodes 10 and 40.

Insulators

28 and 47 that insulate the

outer jackets

11 and 41 from each other, and the central axis C2 of the

secondary torches

2 and 39, that is, the central axis C2 of the

secondary cathodes

10 and 40, The central axis C <b> 1 of the main anode 3 and the main anode 3 and the sub-cathodes 10, 40 are arranged so as to intersect with each other.

The sub-cathodes 10 and 40 are made of a material having a high melting point, such as tungsten. The sub-cathodes 10 and 40 are concentrically held by the sub-mantles 11 and 41 and the

insulators

28 and 47.

The

auxiliary mantles

11 and 41 are provided with

holes

11a and 41a at the tip portions. The

insulators

28, 47 form a swirl flow similar to the

sub-plasma gas inlets

12, 48 for introducing the

sub-plasma gases

13, 49 toward the central axis C 1 of the main anode 3 and the insulator 27 of the main torch 1. Part 50. Further, a sub-plasma gas automatic supply device 30 for introducing the

sub-plasma gases

13 and 49 is connected to the sub-plasma

gas introduction ports

12 and 48, and the sub-plasma gas automatic supply device 30 is controlled as a supply amount control unit. It can be controlled by the device 31.

As shown in FIG. 1, the positive terminal of the main power supply 7 is connected to the sub jacket 11 via the switch 45 after passing through the main anode 3 and the switch 55, and the positive terminal of the sub power supply 42 and the switch 44 are connected. And the negative terminal of the main power source 7 is connected to the main mantle 4 via the switch 8.
The negative terminal of the sub power source 42 is connected to the sub cathode 10 via the switch 46 and the negative terminal of the main power source 7 via the switch 9, and the negative terminal of the main power source 7 via the switch 9. It is connected to the sub-cathode 40 via the terminal and the switch 43.

Next, a method for plasma spraying the thermal spray material 20a using the plasma thermal spray apparatus 100 will be described. Here, the thermal spray material 20a indicates, for example, a conductive material such as metal, an insulating material such as ceramics, and the like.
An inert gas that can be turned into plasma, such as argon or helium, is introduced into the main torch 1 from the main plasma gas inlet 5 as a main plasma gas 6 to form a swirling flow of the main plasma gas 6. Further, with the switch 9 opened and the switch 8 closed, a voltage obtained by superimposing a high frequency high voltage on a DC voltage is applied between the main anode 3 and the main mantle 4 by the main power source 7. As a result, a plasma arc is formed from the tip of the main anode 3 toward the main mantle 4. Even after the superposition of the high-frequency voltage is stopped, the plasma arc is maintained by releasing thermoelectrons from the main mantle 4. The main plasma gas 6 is heated by the plasma arc and becomes a plasma flame 16 which is emitted from the opening 4 a of the main mantle 4.

In addition, an auxiliary gas such as argon or helium, which can be converted into plasma, is used as the secondary plasma gas 13 from the secondary plasma gas automatic supply device 30 controlled by the control device 31 via the secondary plasma gas inlet 12. The swirl flow of the auxiliary plasma gas 13 is formed. Further, with the

switches

43 and 44 opened and the

switches

45 and 46 closed, a voltage obtained by superimposing a high frequency high voltage on a DC voltage is applied between the sub cathode 10 and the sub jacket 11 by the sub power source 42. As a result, a secondary plasma arc is formed from the tip 10 a of the secondary cathode 10 toward the secondary jacket 11. Even after the superposition of the high frequency high voltage is stopped, the plasma arc is maintained by thermionic emission from the sub-cathode 10 as in the conventional torch. The sub-plasma gas 13 is heated by the plasma arc, and becomes a plasma flame 17 and is emitted from the hole 11 a of the sub-clutch 11.

Since the central axis C1 of the main anode 3 and the central axis C2 of the sub-cathode 10 intersect outside the main torch 1 and the sub-torch 2 in front of the main anode 3 and the sub-cathode 10, plasma emitted from the main torch 1 A conductive path is formed by the flame 16 and the plasma flame 17 emitted from the auxiliary torch 2. In this state, when the

switches

45 and 46 are opened after the switch 9 is closed, the plasma arc generated in the main torch 1 and the sub torch 2 converges, and instead, from the tip 10a of the sub cathode 10 to the main anode. A hairpin-shaped plasma arc reaching the anode point 3 is formed.

Thereafter, an inert gas that can be turned into plasma, such as argon or helium, is used as the secondary plasma gas 49 from the secondary plasma gas automatic supply device 30 controlled by the control device 31 via the secondary plasma gas inlet 48. And a swirling flow of the auxiliary plasma gas 49 is formed. Further, with the

switches

43 and 44 closed, a voltage obtained by superimposing a high frequency high voltage on a DC voltage is applied between the sub cathode 40 and the sub jacket 41 by the sub power source 42. As a result, a plasma arc is formed from the tip 40a of the sub cathode 40 toward the sub jacket 41. Even after the superposition of the high frequency high voltage is stopped, the plasma arc is maintained by thermionic emission from the sub-cathode 40 as in the conventional torch. The sub-plasma gas 49 is heated by the plasma arc and becomes a plasma flame 56 which is discharged from the hole 41 a of the sub-mantle jacket 41.

Since the central axis of the main anode 3 and the central axis of the sub-cathode 40 intersect the outside of the main torch 1 and the sub-torch 39 in front of the main anode 3 and the sub-cathode 40, the main axis 3 and the sub-cathode 40 are emitted from the holes 41 a of the sub-cannula 41. The plasma flame 56 intersects the plasma flame 16 formed by heating the plasma gas emitted from the main torch 1 by a hairpin-shaped plasma arc extending from the tip 10 a of the sub-cathode 10 to the anode point of the main anode 3. Thus, a power transmission path is formed between the sub-cathodes 10 and 40 and the main anode 3. In this state, when the switch 44 is opened after the switch 55 is closed, a T-shaped plasma arc from the

tips

10a, 40a of the sub-cathodes 10, 40 to the anode point of the main anode 3 is formed. A plasma flame 23 is formed on the same axis of the main torch 1 by heating the

main plasma gases

6, 13 and 49 emitted from the sub torches 2 and 39 and the main torch 1.

The material supply pipe 19 is supplied with a material supply gas 20 in which a thermal spray material 20a is mixed with an inert gas that can be turned into plasma, such as argon or helium. The thermal spray material 20 a discharged from the material feed pipe 19 through the thermal spray material discharge hole is supplied to the axial center of the plasma flame 23 formed on the central axis of the main anode 3 by the main anode 3 and the sub-cathode 10. And is melted by the plasma flame 23.

The plasma flame 23 includes

sub-plasma gases

13 and 49 from the

holes

11 a and 41 a of the

sub-torches

2 and 39 that intersect the central axis C 1 of the main torch 1, that is, the central axis C 1 of the main anode 3. It is introduced from a direction substantially orthogonal to the central axis C1. For this reason, the plasma flame 23 is pressed to the central axis C1 side of the main anode 3 by the

auxiliary plasma gases

13 and 49 introduced from two directions.

The melt 21 in which the thermal spray material 20 a is melted proceeds toward the base material 25 together with the plasma flame 23. At this time, immediately before the base material 25, a gas suitable for film formation is applied to the base material 25 at a more appropriate temperature by ejecting a gas to the plasma from the plasma trimming unit 22 provided on the connecting pipe 26. By depositing, the high-quality film 24 can be efficiently formed.

In the present embodiment, two sub-torches are provided in the plasma spraying apparatus 100, but three or more sub-torches may be provided. When two or more sub-torches are provided, these sub-torches are arranged so that the central axis of the electrode included in the sub-torch intersects the front of the main anode 3 and at one point of the central axis outside the main torch 1. It is preferable that they are arranged, and it is more preferable that they are evenly arranged on the circumference of a circle perpendicular to the central axis with the intersecting point as the center. When two or more sub-torches are provided in the plasma spraying apparatus 100, each sub-torch is arranged so that the central axis of each sub-torch intersects the central axis of the main torch perpendicularly at the above-mentioned intersection. Preferably it is.

In the plasma spraying apparatus 100 described in the above embodiment, in the conventional plasma spraying apparatus, the main electrode is a cathode that needs to emit a quantity of thermoelectrons to maintain a plasma arc, whereas the main anode 3 Is an anode whose temperature is lower than that of the sub-cathodes 10 and 40, preventing the supplied sprayed material from adhering to the softened main electrode. Further, a swirl flow is generated by the main plasma gas 6 introduced into the main torch 1 having the main anode, and the adhesion of the sprayed material 20a into the main torch 1 is suppressed, so that the sprayed material discharge hole 19a becomes the sprayed material 20a. It is prevented from being blocked by.

In this way, by suppressing the adhesion of the thermal spray material 20a into the main electrode and the main torch 1, in the conventional plasma spraying apparatus, in order to avoid the adhesion of the thermal spray material to the main electrode, the plasma arc is generated outside the torch. While the thermal spray material was supplied from a direction inclined with respect to the central axis of the main electrode to be formed, it became possible to supply the thermal spray material along the central axis of the main electrode. As a result, the thermal spray material can be easily supplied to the center of the plasma flame, and the thermal spray material can be more reliably brought to the high temperature portion of the plasma flame and can be prevented from being scattered to the periphery. That is, it becomes possible to stably supply the thermal spray material to the high temperature part of the plasma flame, and to form a stable coating according to the supply amount of the thermal spray material and the plasma gas.

The inventor of the present application tested the change in the characteristics of the film 24 to be formed using the supply conditions of the

sub-plasma gases

13 and 49 that have not existed as parameters until now. That is, it tried to form the membrane | film | coat 24 by changing supply_amount | feed_rate of

subplasma gas

13,49. FIG. 3 is an image showing a state of the plasma flame 23 when the

auxiliary plasma gases

13 and 49 are introduced from the two

auxiliary torches

2 and 39. FIG. 4 is a graph showing the relationship between the supply amount of the

auxiliary plasma gases

13 and 49 and the thickness of the coating 24 to be formed.

As shown in FIG. 3, the central axis C1 of the main torch 1 is obtained by photographing a plasma flame 23 extending from the spray material discharge hole 19a of the main torch 1 along the central axis C1 of the main torch 1 with a high-speed camera or the like. It was confirmed that the

sub-plasma gases

13 and 49 introduced so as to go from two directions orthogonal to each other toward the central axis C1 of the main torch 1 suppress the air flow of particles diffusing in the direction away from the central axis C1. .

Then, as a result of measuring the film thickness of the formed film 24 with different supply amounts of the

sub-plasma gases

13, 49, as shown in FIG. 4, it is formed when the supply amount of the

sub-plasma gases

13, 49 is increased. It was confirmed that the film thickness of the film 24 was increased.

From these results, it can be seen that the thickness of the film 24 can be changed as a characteristic of the film 24 to be formed by controlling the supply amount of the

sub-plasma gases

13 and 49. That is, the thicker film 24 is formed as the supply amount of the

auxiliary plasma gases

13 and 49 is increased, or the thinner film 24 is formed as the supply amount of the

auxiliary plasma gases

13 and 49 is decreased. Is possible. That is, by forming the coating film 24 by changing the supply amounts of the

sub-plasma gases

13 and 49, it is possible to form the coating film 24 having different film thicknesses.

Further, the inventor measured the hardness of the coating 24 by changing the supply amounts of the

auxiliary plasma gases

13 and 49.
FIG. 5 is a graph showing the relationship between the supply amount of the

auxiliary plasma gases

13 and 49 and the hardness of the coating 24 to be formed. As shown in FIG. 5, the hardness of the coating 24 increases as the supply amount of the

auxiliary plasma gases

13 and 49 increases. From this result, it can be seen that the hardness can be changed as a characteristic of the film 24 formed by controlling the supply amount of the

sub-plasma gases

13 and 49. That is, the film 24 having a high hardness is formed by increasing the supply amount of the

sub-plasma gases

13 and 49, or the film 24 having a low hardness is formed by decreasing the supply amount of the

sub-plasma gases

13 and 49. Is possible.

According to the plasma spraying apparatus 100 of the present embodiment, from the direction intersecting the material supply gas 20 fed along the central axis C1 of the main anode 3, along the central axis C2 of the sub-cathodes 10, 40. Since the control device 31 for controlling the supply amount of the introduced

secondary plasma gases

13 and 49 is provided, when the molten thermal spray material 20a reaches the substrate 25, it acts from the direction intersecting the plasma flame 23. It is possible to form the coating 24 by varying the amount of the

subplasma gas

13 and 49 to be supplied.

Then, the control device 31 controls the supply amount of the

sub-plasma gas

13, 49 to increase the supply amount of the

sub-plasma gas

13, 49 to form the thick film 24, or the sub-plasma gas 13, It is possible to form the thin film 24 by reducing the supply amount of 49. That is, by forming the coating film 24 by changing the supply amount of the

sub-plasma gases

It is also possible to form the coating 24 having different hardness by controlling the supply amount of the

sub-plasma gas

13, 49 by the control device 31. For this reason, it is possible to form the coating 24 having high hardness by increasing the supply amount of the

sub-plasma gases

13 and 49 by the control device 31, and to decrease the supply amount of the

sub-plasma gases

13 and 49. Thus, it is possible to form the coating 24 having a low hardness.

Further, when the plurality of sub torches 2 are evenly arranged in the circumferential direction around the central axis C 1 of the main anode 3 of the main torch 1, the

sub plasma gases

13 and 49 are centered on the central axis C 1 of the main anode 3. Since it acts on the material supply gas 20 evenly from above the circumference, it is possible to cause the

sub-plasma gases

13, 49 to act in a balanced manner.

The control of the auxiliary plasma gas automatic supply device 30 by the control device 31 is, for example, a database based on data as shown in the graphs of FIGS. 4 and 5, that is, the thickness or hardness of the formed film 24 and the auxiliary plasma gas 13, It is possible to generate a characteristic database that associates 49 supply amounts. Based on this characteristic database, the supply amount of the

sub-plasma gases

13 and 49 with respect to the thickness or hardness of the film 24 to be formed is calculated, and the supply amount of the

plasma gases

13 and 49 is controlled according to the conditions, thereby easily It is possible to control the thickness or hardness of the coating.

At this time, at least one of the particle velocity and the particle temperature of the thermal spray material 20a sprayed on the base material 25 is observed with a CCD camera, a spectral luminance meter or the like, and the observation result and the thickness or hardness of the coating 24 to be formed are determined. If the control device 31 controls the supply amounts of the

sub-plasma gases

13 and 49 based on the above, more accurate control is possible and the coating 24 having a desired thickness or hardness can be formed.

FIG. 6 is a diagram showing a schematic configuration of the plasma spraying apparatus 101 in which the main torch 1 and the sub torch 2 are integrated.
In the above-described embodiment, the plasma spraying apparatus 100 in which the main torch 1 and the sub-torch 2 are separately separated has been described. However, as shown in FIG. 6, on the outlet side of the opening 4 a in the outer shell of the main torch 1. An integrated plasma spraying apparatus 101 of the main torch 1 and the

auxiliary torches

2 and 39 provided with the

auxiliary torches

2 and 39 through the insulator 60 may be used.

Further, the above embodiment is for facilitating the understanding of the present invention, and is not for limiting the interpretation of the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof.

1 main torch, 2 sub torch, 3 main anode, 4 main mantle, 4a opening,
4b taper part, 5 main plasma gas inlet, 6 main plasma gas, 7 main power supply,
8, 9 switch, 10 sub cathode, 10a tip of sub cathode, 11 sub jacket, 11a hole, 12 sub plasma gas inlet, 13 sub plasma gas, 14 sub power supply, 15 switch, 16 plasma flame, 17 plasma flame, 18 plasma,
19 Material feeding pipe, 19a Spraying material discharge hole, 20 Material supply gas, 20a Spraying material,
21 melt, 22 plasma trimming section, 23 plasma flame, 24 coating,
25 Substrate, 26 Connecting pipe, 27, 28 Insulator, 30 Sub-plasma gas automatic supply device,
31 control device, 39 sub-torch, 40 sub-cathode, 40a tip of sub-cathode,
41 sub jacket, 41a hole, 42 sub power supply,
43, 44, 45, 46 switch, 47 insulator,
48 sub-plasma gas inlet, 49 sub-plasma gas, 50 swirl flow forming section,
51 gas annular chamber, 52 swirl flow forming hole, 53 inner wall, 55 switch,
56 plasma flame, 60 insulator, 100 twin cathode type plasma spraying device,
101 Integrated plasma spraying device,
C1 central axis of the main anode, C2 central axis of the sub-cathode,

Claims

A main torch comprising a main anode having a material feed pipe for feeding a material supply gas containing a sprayed material along a central axis, and introducing a main plasma gas along the central axis;
A plurality of sub-cathodes comprising a sub-cathode having a central axis intersecting with the central axis of the main anode and being spaced apart from each other in the circumferential direction on a circumference centered on the central axis of the main anode Torch,
Have
A plasma arc formed between the main anode and the sub-cathode;
The main plasma gas introduced along the central axis of the main anode;
The material is applied to the plasma flame formed along the central axis of the main anode by the sub-plasma gas introduced along the central axis of the sub-cathode and toward the central axis of the main anode. In the plasma spraying apparatus in which the material supply gas is fed from a feeding pipe, the sprayed material is melted and sprayed onto a base material to form a coating of the sprayed material,
A plasma spraying apparatus comprising a supply amount control unit for controlling a supply amount of the sub-plasma gas.
2. The plasma spraying apparatus according to claim 1, wherein the supply amount control unit controls the supply amount of the sub-plasma gas so as to change the characteristics of the film to be formed.
The plasma spraying apparatus according to claim 2, wherein the characteristic of the coating is the thickness of the coating to be formed.
4. The plasma spraying apparatus according to claim 3, wherein the supply amount control unit controls the supply amount of the secondary plasma gas to be increased as the thickness of the coating is increased.
The plasma spraying apparatus according to claim 2, wherein the characteristic of the coating is a hardness of the coating to be formed.
6. The plasma spraying apparatus according to claim 5, wherein the supply amount of the sub-plasma gas is controlled to be increased by the supply amount control unit as the hardness of the coating is increased.
Generating a characteristic database associating the characteristic of the film with the supply amount of the secondary plasma gas;
7. The plasma spraying apparatus according to claim 2, wherein the supply amount control unit controls the supply amount of the sub-plasma gas based on the characteristics of the film to be formed and the characteristic database.
The supply amount control unit observes at least one of a particle velocity and a particle temperature of the thermal spray material sprayed on the base material, and based on the observation result and the characteristics of the coating to be formed, the subplasma 7. The plasma spraying apparatus according to claim 2, wherein a gas supply amount is controlled.
The plasma spraying apparatus according to any one of claims 1 to 8, wherein the plurality of sub-torches are arranged uniformly in the circumferential direction.