CN111876722A

CN111876722A - Method for removing surface bulge of ceramic layer

Info

Publication number: CN111876722A
Application number: CN202010720496.5A
Authority: CN
Inventors: 徐俊阳; 郑广文; 陈晨; 李加
Original assignee: Shenyang Fortune Precision Equipment Co Ltd
Current assignee: Shenyang Fortune Precision Equipment Co Ltd
Priority date: 2020-07-24
Filing date: 2020-07-24
Publication date: 2020-11-03

Abstract

The invention relates to a method for removing surface protrusions on the surface of a ceramic layer, which is used for removing the surface protrusions caused by the size distribution of powder particles when a ceramic layer is prepared by thermal spraying by changing a cooling nozzle and other modes so as to remove particles with smaller particle diameters, thereby ensuring that the surface of the ceramic layer prepared by thermal spraying is smooth and has no protrusions. The roughness of the surface of the coating is ensured, and the performance quality of the coating is further ensured.

Description

Method for removing surface bulge of ceramic layer

Technical Field

The invention belongs to the technical field of thermal spraying, and mainly aims to remove projections on the surface of a ceramic coating.

Background

At present, with the more mature technology of preparing ceramic coatings such as aluminum oxide, yttrium oxide and the like by a thermal spraying technology, the application of the prepared coatings is wider and wider, and the bulge formed on the surface of the ceramic coating is a problem which cannot be ignored. Meanwhile, as the requirements for the performance of ceramic coatings are increased, the development of new ceramic coatings, such as yttrium oxyfluoride coatings, etc., is also becoming more and more hot. Whether for the already mature yttria coatings or for the newly developed oxyytrria fluoride coatings, there is a more or less convex appearance of the coating surface during the coating preparation when a performance-demanding coating is obtained. For the bulges, a few bulges exist, so that the service performance of the coating is not influenced; some can affect the coating properties. For these projections which affect the coating properties, it is generally contemplated to reduce these projections by changing the spraying distance, the powder feeding rate, the spraying distance, etc., if it is desired to remove these projections. However, once these parameters are changed, a change in the coating properties of the non-protruding parts results, and it is difficult to predict whether a change in these parameters will have a good or bad effect on the coating properties of the non-protruding parts. Therefore, such a method of changing the main parameter is not suggested, and not only the parameter that needs to be changed is large, but also the influence thereof is unpredictable.

Disclosure of Invention

The invention aims to reduce the raised part of the coating by the most rapid and easily realized mode on the premise of ensuring that the performance of the non-raised coating is not influenced. Generally, these projections are formed because the particle powder diameter for thermal spraying is not a fixed value but is distributed in a range such that there are particles having a large particle diameter and particles having a small particle diameter. For the particles with small particle diameter, in the thermal spraying flame flow, the particles are adsorbed on the substrate without thermal deformation due to light weight and short residence time, and the particles are circular particles and are not thermally deformed in the flame flow, so that the circular particles are still retained when being adsorbed on the substrate, and thus, the protrusions on the surface of the coating are formed after being accumulated layer by layer. To reduce the projections, it is essential to reduce the number of unmelted particles.

In order to achieve the purpose, the invention adopts the technical scheme that:

(1) firstly, observing the distribution of bulges on the surface of a coating, and judging whether the bulges need to be removed;

(2) for the projection needing to be removed, performing performance detection and comparison on the projection surface and the non-projection surface of the coating;

(3) for a bump surface with poor coating performance, the bump needs to be reduced, and the number of cooling nozzles can be added and the angle of the cooling nozzles can be adjusted.

(4) If through above-mentioned mode, it is not detailed enough to reduce protruding effect, can readjust the rotational speed of carousel.

The invention has the advantages that:

1. the invention can reduce the bulge without influencing the overall performance of the coating.

2. The invention has simple operation and does not influence the main technological parameters of thermal spraying.

Drawings

FIG. 1 is a schematic view of the invention for removing the coating surface protrusions.

Detailed Description

The invention will now be described in detail with reference to the accompanying figure 1 and examples.

A method for removing surface bumps on a ceramic layer comprises (1) observing the distribution of the bumps on the surface of the ceramic layer; (2) respectively carrying out performance test on the convex part and the non-convex part on the surface of the ceramic layer and comparing; (3) if the performance difference occurs and the performance of the convex part is worse, the convex part needs to be removed; (4) changing the number and distance of the cooling nozzles 1; (5) the rotation speed of the turntable 2 is adjusted.

Example one

Firstly, when the yttrium oxide coating sprayed by the atmospheric plasma spraying process has more protrusions on the surface, the protrusions and the non-protrusions are subjected to corrosion resistance tests, and the corrosion resistance of the protrusions is obviously lower than that of the non-protrusions, so that the corrosion resistance of the non-protrusions can meet the requirements, and therefore, the protrusions on the surface of the coating need to be removed.

Secondly, a cooling nozzle 1 is added on the premise of not changing the spraying parameters, and the position of the cooling nozzle 1 is arranged between the two nozzles.

And thirdly, when the spraying is carried out again, other spraying parameters are not changed, and the cooling nozzle is added, so that the extremely small particles in the sprayed powder are blown away and deviate from the center of the thermal spraying flame flow 4 sprayed by the spray gun 5, and thus, the particle diameter range of the powder particles heated on the surface of the part 3 is reduced, and more particles are uniformly heated.

Finally, because increase the cooling nozzle for the granule that is littleer in the powder is blown away, has guaranteed that other granules are heated more evenly in the spraying flame flows, makes the granule all be the platykurtic to the base member surface, and it is inhomogeneous so to have reduced the granule because be heated, leads to can't be the platykurtic and hits the base member surface, has hit the bellied purpose in reduction coating surface.

Example two

Firstly, spraying a yttrium fluoride coating by using a supersonic flame spraying technology, after spraying, finding that a plurality of convex parts appear on the surface of the coating, carrying out breakdown voltage resistance test on the convex parts and non-convex parts, finding that the test result of the convex parts is unqualified, and the test result of the non-convex parts is qualified, thus the convex parts need to be removed.

Secondly, because the coating performance of the non-convex part is qualified, the convex part on the surface of the coating is removed on the premise of not changing the spraying parameters, and a cooling nozzle is respectively added from two sides.

Thirdly, when spraying again, the original spraying parameters are not changed, only one cooling nozzle is respectively added from the left side and the right side, and when spraying, the added nozzles blow away smaller powder particles to enable the powder particles to deviate from the spraying flame flow; on the other hand, particles with proper sizes are more concentrated in the center of the flame flow, so that the particles are heated more uniformly.

Finally, because the small particles are blown away, the phenomenon that the particles are directly hit on the substrate without being flat due to the fact that the particles are too small, the particles are too fast in speed and too short in heating time, and the protrusions are formed layer by layer is reduced. In addition, because small particles are reduced, particles with proper diameters are more gathered in the flame flow, the particles are heated more uniformly, and bulges formed due to nonuniform heating of the particles are reduced.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and combinations are possible for those skilled in the art. The method is mainly used for removing the bulges on the surface of the coating in the process of preparing the ceramic layer by the thermal spraying mode. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for removing bumps on the surface of a ceramic layer, comprising:

(1) firstly, observing the distribution of bulges on the surface of the ceramic layer;

(2) respectively carrying out performance test on the convex part and the non-convex part on the surface of the ceramic layer and comparing;

(3) if the performance difference occurs and the performance of the convex part is worse, the convex part needs to be removed;

(4) changing the number and distance of the cooling nozzles;

(5) the rotation speed of the rotary table is adjusted.

2. The method for removing the surface protrusions of the ceramic layer according to claim 1, wherein in the step (1), the ceramic coating is prepared by thermal spraying, such as atmospheric plasma spraying or supersonic flame spraying. Whether the distribution of the protrusions on the surface of the ceramic coating is serious or not is firstly mastered.

3. The method according to claim 1, wherein in the step (2), it is determined whether the protrusions on the surface of the ceramic coating have negative effects, not only whether the protrusions affect the appearance of the ceramic layer, but also whether the protrusions affect the performance, and the general performance tests include corrosion resistance and hardness tests.

4. The method for removing the surface protrusions on the ceramic layer according to claim 1, wherein in the steps (3), (4) and (5), when the protrusions on the ceramic coating have an influence on the performance, the protrusions are removed by changing the rotation speed of the cooling nozzle and the rotation table under the condition that the main thermal spraying parameters are not changed; not only does not change the main spraying parameters, but also achieves the purpose of removing the protrusions on the surface of the ceramic layer.