Feeding device for suspension plasma spraying for the production of columnar crystal microstructure coatings

Abstract

The application belongs to the technical field of suspension plasma spraying, and particularly relates to a feeding device for preparing a columnar crystal microstructure coating by suspension plasma spraying, which solves the technical defects of a conventional two-fluid atomizer, such as too large radial distance between the nozzle end and the center of the plasma jet or difficulty in assembling with the plasma torch, and comprises a two-fluid atomizing nozzle, a stirring device, a peristaltic pump, an air compressor and a clamping tool. The air cap extends with a neck part connected in the middle. The stirring device is connected to the peristaltic pump through a liquid pipe. The peristaltic pump is connected to the liquid inlet of the two-fluid atomizing nozzle through a liquid pipe. The air compressor is connected to the air inlet of the two-fluid atomizing nozzle through an air pipe. The clamping tool is used for fixing and mounting the air cap to the front end of the plasma torch. The neck outlet of the air cap is located at the front end of the plasma torch. The elongated neck of the air cap and the special clamping tool can make the suspension liquid after sufficient atomization treatment be more concentratedly sent into the plasma jet.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of suspension plasma spraying, in particular to a feeding device for preparing columnar crystal microstructure coating by suspension plasma spraying. BACKGROUND

[0002] Suspension plasma spraying is a new coating preparation technology, which uses suspension instead of powder for direct feeding, so as to solve the problems of poor flowability and difficult feeding of small particle size powder, and to prepare columnar crystal microstructure coating at a low cost. The columnar crystal microstructure coating has high strain tolerance and is of great significance to the improvement of coating service life. However, according to the current public reports, there is no simple and convenient low-cost device that can be directly assembled to a conventional atmospheric plasma spraying gun to realize suspension plasma spraying, except for expensive imported commercial devices, for preparing columnar crystal microstructure coating with high strain tolerance characteristics.

[0003] However, there are many disadvantages in directly using a conventional two-fluid atomizer as a suspension plasma spraying feeding device. Figure 1 As shown in the conventional two-fluid atomizing nozzle structure schematic diagram, it is composed of an adjusting needle assembly 1, a nozzle body 2, a liquid cap 3, a connecting screw cap 4, and an air cap 5. The nozzle body is provided with a liquid inlet for connecting a liquid pipe and an air inlet for connecting an air pipe. If this conventional two-fluid atomizer is used, the radial distance between the nozzle tip and the center of the plasma jet is too large, so that the atomized droplets have a large spraying range before reaching the plasma jet, which cannot be concentrated into the plasma jet, affecting the coating deposition rate. In addition, as shown in Figure 2 and Figure 3 As shown, the existing air cap is difficult to assemble with the plasma spraying gun, and the axial distance between the nozzle and the end surface of the plasma spraying gun after assembly is too large, so that the atomized droplets cannot be effectively heated, affecting the coating deposition quality.

[0004] Therefore, we propose a feeding device for preparing columnar crystal microstructure coating by suspension plasma spraying to solve the above problems. SUMMARY

[0005] In order to overcome the technical defects of the conventional two-fluid atomizer, such as the radial distance between the nozzle tip and the center of the plasma jet being too large or being difficult to assemble with the plasma spraying gun, the present application provides a feeding device for preparing columnar crystal microstructure coating by suspension plasma spraying, which can be directly assembled to a conventional atmospheric plasma spraying gun and can realize the preparation of columnar crystal microstructure coating by suspension plasma spraying.

[0006] The application provides a feeding device for preparing columnar crystal microstructure coating by suspension plasma spraying, which comprises a two-fluid atomizing nozzle, the two-fluid atomizing nozzle comprising an adjusting needle assembly, a nozzle body, a liquid cap, a connecting cap and an air cap, characterized in that further comprising a stirring device, a peristaltic pump, an air compressor and a clamping tool, the air cap has a neck part connected with the air cap in the middle along the axis of the air cap in the opposite direction of the connecting cap, the stirring device is connected with the liquid inlet of the peristaltic pump through a liquid pipe, the liquid outlet of the peristaltic pump is connected with the liquid inlet of the two-fluid atomizing nozzle through a liquid pipe, the air compressor is connected with the air inlet of the two-fluid atomizing nozzle through a gas pipe, the air compressor is additionally provided with a precision pressure regulating valve, and the clamping tool is used for fixing and mounting the air cap to the front end of the plasma torch, and the neck outlet of the air cap is located on the upper side of the front end outlet of the plasma torch. The two-fluid atomizing nozzle atomizes the input suspension, and the atomized suspension is sprayed out through the elongated neck part and enters the plasma jet sprayed out by the plasma torch to realize spraying. The elongated neck part of the air cap can realize concentrated and stable delivery of the atomized suspension droplets, and facilitates clamping of the air cap to the front end of the plasma torch.

[0007] Preferably, the clamping tool comprises a support plate and a U-shaped clamp, the U-shaped clamp is used for fixing the neck part of the air cap on the support plate, the U-shaped clamp is fixedly connected with the support plate through a plurality of internal hexagonal nuts, the support plate extends two oppositely arranged arc-shaped clamping arms, the free ends of the arc-shaped clamping arms are connected through a fastening bolt assembly, and a clamping structure for clamping the front end part of the plasma torch is formed between the two arc-shaped clamping arms. The length of the neck part of the air cap extending out can be adjusted through the U-shaped clamp and the internal hexagonal nut, thereby adjusting the distance between the neck outlet of the air cap and the plasma jet, and controlling the angle of the atomized suspension droplets entering the central region of the plasma jet. The clamping tightness of the two arc-shaped clamping arms can be adjusted through the adjusting of the fastening bolt assembly, thereby adjusting the relative position of the clamping tool and the front end part of the plasma torch. In this way, the structure is simple and convenient to adjust.

[0008] Preferably, the diameter d of the neck outlet of the air cap is 0.15-0.5 mm, and the length h of the neck part of the air cap is 20-50 mm.

[0009] Preferably, the stirring rate of the stirring device is 100-2000 rpm. A knob is arranged on the stirring device to control the stirring rate of the suspension.

[0010] Preferably, the input flow of the peristaltic pump is 5-35 ml·min -1 A knob is arranged on the peristaltic pump to control the flow of the input suspension.

[0011] Preferably, the pressure regulating range of the precision regulating valve of the air compressor is 0.01-0.4 Mpa.

[0012] Compared with the prior art, the technical scheme provided by the present application has the following beneficial effects: the manufacturing cost of each component in the present application is low, the manufacturing material is easy to obtain, the feeding device can be directly clamped to a conventional atmospheric ion spray gun, the specially-made air cap is provided with an elongated neck, the neck outlet is located on the front end outlet of the plasma spray gun in the uplink direction, so that the suspension can be more concentratedly fed into the plasma jet after being sufficiently atomized, and the air cap can be made closer to the front end surface of the plasma spray gun through the specially-made clamping tool, so that the atomized droplets are heated more sufficiently, which is beneficial to improving the coating deposition efficiency and coating quality; at the same time, the melting state of the atomized droplets entering the plasma jet can be adjusted by adjusting the feeding speed of the suspension and the atomization pressure with the help of the peristaltic pump and the air compressor, and combining with the control of the spraying process parameters, so that the further precise regulation and control of the coating microstructure can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0013] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0014] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows, and obviously, other accompanying drawings can also be obtained by those skilled in the art without any creative effort on the premise of not paying any creative effort.

[0015] Figure 1 It is a schematic diagram of a conventional two-fluid atomizing nozzle structure in the background art of the present application;

[0016] Figure 2 It is a front view of a conventional two-fluid atomizing nozzle combined with a plasma spray gun in the background art of the present application;

[0017] Figure 3 It is a side view of a conventional two-fluid atomizing nozzle combined with a plasma spray gun in the background art of the present application;

[0018] Figure 4 It is a schematic diagram of the overall structure of the feeding device for preparing a columnar crystal microstructure coating by plasma spraying of a suspension in an embodiment of the present application;

[0019] Figure 5 It is a schematic diagram of the structure of the two-fluid atomizing nozzle in an embodiment of the present application;

[0020] Figure 6 It is a schematic diagram of the structure of the air cap of the two-fluid atomizing nozzle in an embodiment of the present application, which is provided with a neck;

[0021] Figure 7Structure diagram of the clamping tool in some embodiments of the present application;

[0022] Figure 8 Assembly diagram of the clamping tool and the two-fluid atomizing nozzle in some embodiments of the present application;

[0023] Figure 9 Diagram of the coating sprayed by the feeding device for preparing columnar crystal microstructure coating by suspension plasma spraying in the present application.

[0024] In the figure: 1, adjusting needle assembly; 2, nozzle body; 3, liquid cap; 4, connecting screw cap; 5, air cap; 6, two-fluid atomizing nozzle; 7, stirring device; 8, peristaltic pump; 9, air compressor; 10, clamping tool; 11, neck; 12, plasma torch; 13, support plate; 14, U-shaped clamp; 15, inner hexagonal nut; 16, arc-shaped clamping arm; 17, fastening bolt assembly. DETAILED DESCRIPTION

[0025] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the schemes of the present application will be further described below. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0026] In the description, it should be noted that, unless otherwise explicitly specified and limited, the terms “mounting”, “connecting” and “connection” should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meanings of the above-mentioned terms can be understood according to the specific circumstances.

[0027] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein; obviously, the examples in the description are only some of the embodiments of the present application, not all the embodiments.

[0028] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Figures 1 to 9 The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0029] In one embodiment, as shown in FIG. 1, the clamping tool comprises a nozzle body 2, a liquid cap 3, a connecting screw cap 4, an air cap 5, a two-fluid atomizing nozzle 6, a stirring device 7, a peristaltic pump 8, an air compressor 9, a clamping tool 10, a neck 11, a plasma torch 12, a support plate 13, a U-shaped clamp 14, an inner hexagonal nut 15, an arc-shaped clamping arm 16 and a fastening bolt assembly 17. Figure 4As shown, a feeding device for preparing columnar crystal microstructure coating by suspension plasma spraying is disclosed, which comprises a two-fluid atomizing nozzle 6 including an adjusting needle assembly 1, a nozzle body 2, a liquid cap 3, a connecting nut 4 and an air cap 5, characterized in that it further comprises a stirring device 7, a peristaltic pump 8, an air compressor 9 and a clamping tool 10, the air cap 5 has a neck 11 extending along its axis in the opposite direction of the connecting nut 4, the stirring device 7 is connected to the liquid inlet of the peristaltic pump 8 through a liquid pipe, the liquid outlet of the peristaltic pump 8 is connected to the liquid inlet of the two-fluid atomizing nozzle 6 through a liquid pipe, the air compressor 9 is equipped with a precision pressure regulating valve and is connected to the air inlet of the two-fluid atomizing nozzle 6 through an air pipe, the clamping tool 10 is used to fix the air cap 5 to the front end of a plasma torch 12, and the outlet of the neck 11 of the air cap 5 is located on the upper side of the outlet of the front end of the plasma torch 12. The stirring device 7 drives the blade to stir the suspension to be sprayed, the well-stirred suspension is connected to the peristaltic pump 8 through a liquid pipe, the peristaltic pump 8 pumps the suspension to the liquid inlet of the two-fluid atomizing nozzle 6 through a liquid pipe, the air compressor 9 injects compressed air into the two-fluid atomizing nozzle 6, the two-fluid atomizing nozzle 6 atomizes the input suspension and sprays it out through the slender neck 11 into the plasma jet sprayed by the plasma torch 12 to realize spraying. The slender neck 11 of the air cap 5 can realize the centralized and stable delivery of the atomized droplets of the suspension and facilitate the clamping of the front end of the plasma torch 12.

[0030] On the basis of the above-mentioned embodiment, in a preferred embodiment, the clamping tool 10 comprises a support plate 13 and a U-shaped clamp 14, the U-shaped clamp 14 is used to fix the neck 11 of the air cap 5 on the support plate 13, the U-shaped clamp 14 is fixedly connected with the support plate 13 through a plurality of internal hexagonal nuts 15, the support plate 13 extends two oppositely arranged arc-shaped clamping arms 16, the free ends of the arc-shaped clamping arms 16 are connected through a fastening bolt assembly 17, and a clamping structure for clamping the front end of the plasma torch 12 is formed between the two arc-shaped clamping arms 16. The length of the neck 11 of the air cap 5 extending out of the U-shaped clamp 14 and the internal hexagonal nut 15 can be adjusted, thereby adjusting the distance between the outlet of the neck 11 of the air cap 5 and the plasma jet and controlling the angle of the atomized droplets of the suspension entering the central region of the plasma jet. The clamping tightness of the two arc-shaped clamping arms 16 can be adjusted by adjusting the fastening bolt assembly 17, thereby adjusting the relative position of the clamping tool 10 and the front end of the plasma torch 12. Such a structure is simple and convenient to adjust.

[0031] Based on the above embodiments, in a preferred embodiment, the orifice diameter d of the neck 11 outlet of the air cap 5 is 0.15~0.5 mm, and the length h of the neck 11 of the air cap 5 is 20~50 mm. By adjusting the extension length of the neck 11 of the air cap 5, the state of the atomized droplets entering the plasma jet can be adjusted, thereby achieving further control over the coating microstructure; it can reduce the loss of liquid material during transportation, and at the same time allow the atomized suspension to enter the plasma jet more quickly, ensuring the melting state of the atomized droplets in the plasma jet.

[0032] Based on the above embodiments, in a preferred embodiment, the stirring rate of the stirring device 7 is 100~2000 rpm. The stirring device 7 is equipped with a knob to control the stirring rate of the suspension.

[0033] Based on the above embodiments, in a preferred embodiment, the input flow rate of the peristaltic pump 8 is 5~35 ml·min. -1 The peristaltic pump 8 is equipped with a knob to control the flow rate of the input suspension.

[0034] Based on the above embodiments, in a preferred embodiment, the pressure adjustment range of the precision regulating valve on the air compressor 9 is 0.01~0.4 MPa.

[0035] The feeding device described in this invention for preparing columnar crystal microstructure coatings by suspension plasma spraying was used to spray a 20 wt% solid content Ba(Mg) coating. 1 / 3 Ta 2 / 3 O3 coating.

[0036] like Figure 9 As shown, columnar crystalline microstructures with high strain tolerance characteristics can be clearly observed in the cross-sectional microstructure of the coating. This proves that it is feasible to prepare columnar crystalline coatings with high strain tolerance characteristics using the method described above for preparing columnar crystalline microstructure coatings for suspension plasma spraying.

[0037] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Although detailed descriptions have been provided with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and they should all be covered within the protection scope of the claims.

Claims

1. A feed device for suspension plasma spraying for the production of columnar crystal microstructure coatings, comprising a two-fluid atomizing torch (6), the two-fluid atomizing torch (6) comprising an adjustment needle assembly (1), a nozzle body (2), a liquid cap (3), a connecting nut (4) and an air cap (5), characterized in that The air cap (5) has a neck (11) extending along its axis in the opposite direction of the connecting nut (4) with an intermediate communication, the stirring device (7) is connected to the liquid inlet of the peristaltic pump (8) through a liquid pipe, the liquid outlet of the peristaltic pump (8) is connected to the liquid inlet of the two-fluid atomizing nozzle (6) through a liquid pipe, the air compressor (9) is connected to the gas inlet of the two-fluid atomizing nozzle (6) through a gas pipe, the air compressor (9) is additionally provided with a precision regulating valve, the clamping tool (10) is used to fix the air cap (5) to the front end of the plasma torch (12), and the outlet of the neck (11) of the air cap (5) is located on the upper side of the outlet of the plasma torch (12).

2. The feedstock apparatus for suspension plasma spraying to produce a columnar crystalline microstructure coating according to claim 1, wherein, The clamping tool (10) comprises a support plate (13) and a U-shaped clamp (14), the U-shaped clamp (14) is used to fix the neck (11) of the air cap (5) on the support plate (13), the U-shaped clamp (14) and the support plate (13) are fixedly connected through a plurality of internal hexagonal nuts (15), the support plate (13) extends two oppositely arranged arc-shaped clamping arms (16), the free ends of the arc-shaped clamping arms (16) are connected through a fastening bolt assembly (17), and the two arc-shaped clamping arms (16) form a clamping structure for clamping the front end of the plasma torch (12).

3. The feedstock apparatus for suspension plasma spraying to produce a columnar crystalline microstructure coating according to claim 2, wherein, The diameter d of the outlet of the neck (11) of the air cap (5) is 0.15-0.5 mm, and the length h of the neck (11) of the air cap (5) is 20-50 mm.

4. The feedstock apparatus for suspension plasma spraying to produce a columnar crystalline microstructure coating according to claim 3, wherein, The stirring rate of the stirring device (7) is 100-2000 rpm.

5. The feedstock apparatus for suspension plasma spraying to produce a columnar crystalline microstructure coating according to claim 4, wherein, The input flow of the peristaltic pump (8) is between 5 and 35 ml min -1 .

6. The feedstock apparatus for suspension plasma spraying production of columnar crystalline microstructure coating according to claim 5, characterized in that, The pressure regulating range of the precision regulating valve on the air compressor (9) is 0.01-0.4 Mpa.

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