阅读说明：本技术 一种硅碳棒冷端冷态覆铝方法 (Cold-state aluminum coating method for cold end of silicon carbide rod ) 是由 高雨生 于 2020-06-29 设计创作，主要内容包括：本发明提供了一种硅碳棒冷端冷态覆铝方法。该技术方案利用铝粉、丙烯酸乳液、分散剂、消泡剂、流平剂、增稠剂及去离子水等作为原料,按一定比例和次序混匀,制成水性丙烯酸铝粉漆；然后,将水性丙烯酸铝粉漆均匀覆在硅碳棒冷端部的表面；最后,经自然晾干或烘干即成覆铝层。本发明采用冷态敷铝方法,工艺简单,成本低廉,效果与喷铝相当；以丙烯酸乳液作为成膜物质,保证了铝膜具有优异的硬度和附着力；稀料与铝粉末以合理的浓度敷于硅碳棒冷端部表面,形成结合牢固的铝层,使用过程中不易脱落,且保证了良好的导电性。(The invention provides a cold-state aluminum coating method for a cold end of a silicon carbide rod. The technical scheme is that aluminum powder, acrylic emulsion, a dispersing agent, a defoaming agent, a flatting agent, a thickening agent, deionized water and the like are used as raw materials and are uniformly mixed according to a certain proportion and sequence to prepare the water-based acrylic aluminum powder paint; then, uniformly coating the water-based acrylic aluminum powder paint on the surface of the cold end part of the silicon-carbon rod; finally, the aluminum-coated layer is obtained by natural drying or baking. The invention adopts the cold state aluminum coating method, the process is simple, the cost is low, and the effect is equivalent to that of aluminum spraying; the acrylic emulsion is used as a film forming substance, so that the aluminum film has excellent hardness and adhesive force; the thin material and the aluminum powder are applied to the surface of the cold end of the silicon-carbon rod in reasonable concentration to form a firmly combined aluminum layer, the aluminum layer is not easy to fall off in the using process, and good conductivity is ensured.)

1. A cold-state aluminum coating method for a cold end of a silicon carbide rod is characterized by comprising the following steps: uniformly coating the water-based acrylic aluminum powder paint on the surface of the cold end of the silicon-carbon rod, and then drying; the water-based acrylic aluminum powder paint comprises the following components in percentage by mass: 30.0-45.0 percent of acrylic emulsion, 15.0-20.0 percent of deionized water, 2.5-4.0 percent of dispersant, 10.0-25.0 percent of cosolvent, 35.0-50.0 percent of water-based aluminum powder, 0.1-0.3 percent of defoaming agent, 1.0-1.5 percent of thickening agent and 0.1-0.2 percent of flatting agent.

2. The cold-state aluminum coating method for the cold end of the silicon carbide rod as claimed in claim 1, wherein the water-based acrylic aluminum powder paint comprises the following components in percentage by mass: 30.0-45.0 percent of acrylic emulsion, 15.0-20.0 percent of deionized water, 2.5-4.0 percent of dispersant, 10.0-25.0 percent of cosolvent, 35.0-50.0 percent of water-based aluminum powder, 0.1-0.3 percent of defoaming agent, 1.0-1.5 percent of thickening agent and 0.1-0.2 percent of flatting agent.

3. The cold-state aluminum coating method for the cold end of the silicon carbide rod as claimed in claim 1, wherein the cosolvent is propylene glycol methyl ether cosolvent.

4. The cold-state aluminum coating method for the cold end of the silicon carbide rod as claimed in claim 1, wherein the water-based acrylic aluminum powder paint is prepared by the following steps: mixing and dispersing the water-based aluminum powder, the cosolvent, the dispersant and a part of deionized water according to the formula ratio to obtain an aluminum paste dispersion liquid; and mixing the obtained aluminum paste dispersion liquid with the acrylic emulsion, the deionized water, the defoaming agent and the leveling agent according to the formula ratio, stirring at the rotating speed of 300-400 r/min, adding the thickening agent according to the formula ratio when the temperature reaches 30-45 ℃ in the stirring process, and stirring uniformly to obtain the water-based acrylic aluminum powder paint.

5. The cold-side aluminum coating method for the silicon carbide rod as claimed in claim 1, wherein the dispersant is a wetting dispersant of BYK190 type available from Bick chemical company of Germany; the addition amount of the dispersant is 0.1-0.6%.

6. The cold-state aluminum coating method for the cold end of the silicon carbide rod as claimed in claim 1, wherein the aluminum powder particles in the water-based aluminum powder are in a shape of a rolled body, are in a shape of scale and have a thickness of 0.1-1.5 μm; the particle size of the particles is 10-150 μm.

7. The cold-state aluminum coating method for the cold end of the silicon carbide rod as claimed in claim 1, wherein the aqueous aluminum powder comprises 65-70% of aluminum powder and 30-35% of solvent.

8. A cold-state aluminum coating method for a silicon carbide rod cold end as claimed in claim 1, wherein the coating method is selected from the group consisting of: cold spraying, dipping, brushing or rolling.

9. The cold-state aluminum coating method for the cold end of the silicon carbide rod as claimed in claim 1, which is characterized by comprising the following steps: loading, cleaning, coating, draining paint, drying and unloading; wherein the cleaning is grinding or purging.

10. The cold-state aluminum coating method for the cold end of the silicon carbide rod as claimed in claim 1, wherein the drying method is natural airing or drying; the drying temperature is 60-100 ℃.

Technical Field

The invention relates to the technical field of silicon carbide electric heating elements, in particular to a cold-state aluminum coating method for a cold end of a silicon-carbon rod.

Background

In order to ensure that the cold end of a silicon carbide electric heating element (silicon carbon rod for short) is tightly contacted with the conductive chuck and reduce the contact resistance, the cold end of the silicon carbon rod needs to be coated with aluminum. The traditional aluminum coating method of the silicon-carbon rod is thermal spraying, commonly called aluminum spraying, namely an electric sprayer or a metal flame sprayer is used for melting an aluminum wire into liquid by electric or oxyacetylene flame, and the molten aluminum is sprayed to the cold end part of the silicon-carbon rod under the blowing of compressed air so as to improve the conductivity of the connection part of the silicon-carbon rod.

The traditional thermal aluminum spraying process is complex, high in operation requirement and large in cost investment. In addition, the aluminum powder can fly in the aluminum spraying process, so that environmental pollution is easily caused, and the flying dust needs to be recovered by a special negative pressure water bath box. Therefore, it is necessary to develop a method for covering aluminum in a cold state, which is easy to operate and low in cost. Meanwhile, the cold-state aluminum-coated layer can be firmly combined with the silicon carbide rod body, and good conductivity is ensured.

Disclosure of Invention

The invention aims to overcome the technical defects of the prior art and provides a cold-state aluminum coating method for a cold end of a silicon-carbon rod so as to solve the technical problems of complex process, high cost and environmental pollution of the traditional thermal aluminum spraying process in the prior art.

The invention also aims to solve the technical problem of how to ensure that the cold-state aluminum-coated layer can be firmly combined with the silicon carbide rod body and ensure good conductivity when the cold-state aluminum-coated process is adopted.

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

a cold-state aluminum coating method for a cold end of a silicon carbide rod comprises the following steps: uniformly coating the water-based acrylic aluminum powder paint on the surface of the cold end of the silicon-carbon rod, and then drying; the water-based acrylic aluminum powder paint comprises the following components in percentage by mass: 30.0-45.0 percent of acrylic emulsion, 15.0-20.0 percent of deionized water, 2.5-4.0 percent of dispersant, 10.0-25.0 percent of cosolvent, 35.0-50.0 percent of water-based aluminum powder, 0.1-0.3 percent of defoaming agent, 1.0-1.5 percent of thickening agent and 0.1-0.2 percent of flatting agent.

Preferably, the water-based acrylic aluminum powder paint consists of the following components in percentage by mass: 30.0-45.0 percent of acrylic emulsion, 15.0-20.0 percent of deionized water, 2.5-4.0 percent of dispersant, 10.0-25.0 percent of cosolvent, 35.0-50.0 percent of water-based aluminum powder, 0.1-0.3 percent of defoaming agent, 1.0-1.5 percent of thickening agent and 0.1-0.2 percent of flatting agent.

Preferably, the cosolvent is propylene glycol methyl ether cosolvent.

Preferably, the water-based acrylic aluminum paint is prepared by the following method: mixing and dispersing the water-based aluminum powder, the cosolvent, the dispersant and a part of deionized water according to the formula ratio to obtain an aluminum paste dispersion liquid; and mixing the obtained aluminum paste dispersion liquid with the acrylic emulsion, the deionized water, the defoaming agent and the leveling agent according to the formula ratio, stirring at the rotating speed of 300-400 r/min, adding the thickening agent according to the formula ratio when the temperature reaches 30-45 ℃ in the stirring process, and stirring uniformly to obtain the water-based acrylic aluminum powder paint.

Preferably, the dispersant is a wetting dispersant with model number BYK190, which is manufactured by Bick chemical company of Germany; the addition amount of the dispersant is 0.1-0.6%.

Preferably, the aluminum powder particles in the water-based aluminum powder are in a rolling body shape, are in a scaly shape and have a thickness of 0.1-1.5 microns; the particle size of the particles is 10-150 μm.

Preferably, the aqueous aluminum powder contains 65-70% of aluminum powder and 30-35% of solvent.

Preferably, the method of coating is selected from: cold spraying, dipping, brushing or rolling.

Preferably, the method specifically comprises the following steps: loading, cleaning, coating, draining paint, drying and unloading; wherein the cleaning is grinding or purging.

Preferably, the drying method is natural airing or drying; the drying temperature is 60-100 ℃.

The invention provides a cold-state aluminum coating method for a cold end of a silicon carbide rod. The technical scheme uses aluminum powder, acrylic emulsion, dispersant, defoamer, flatting agent, thickener, deionized water and the like as raw materials, and the raw materials are uniformly mixed according to a certain proportion and sequence to prepare the water-based acrylic aluminum powder paint (also called silver paste paint); then, uniformly coating the water-based acrylic aluminum powder paint on the surface of the cold end part of the silicon-carbon rod; finally, the aluminum-coated layer is obtained by natural drying or baking. In the invention, the water-based acrylic aluminum powder paint is easy to prepare, and the formed film has excellent conductivity and is firmly adhered to the silicon carbide substrate; and the coating technology has low requirement, simple process and no environmental pollution.

The technical advantages of the invention are focused on the following aspects:

(1) the cold-state aluminum coating method is adopted, the process is simple, the cost is low, and the effect is equivalent to that of aluminum spraying.

(2) The acrylic emulsion is used as a film forming substance, so that the aluminum film has excellent hardness and adhesive force.

(3) The thin material and the aluminum powder are applied to the surface of the cold end of the silicon-carbon rod in reasonable concentration to form a firmly combined aluminum layer, the aluminum layer is not easy to fall off in the using process, and good conductivity is ensured.

Detailed Description

Hereinafter, specific embodiments of the present invention will be described in detail. Well-known structures or functions may not be described in detail in the following embodiments in order to avoid unnecessarily obscuring the details. Approximating language, as used herein in the following examples, may be applied to identify quantitative representations that could permissibly vary in number without resulting in a change in the basic function. Unless defined otherwise, technical and scientific terms used in the following examples have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

A cold-state aluminum coating method for a cold end of a silicon carbide rod mainly comprises the following characteristics:

aluminum powder, acrylic emulsion, a dispersing agent, a defoaming agent, a leveling agent, a thickening agent, deionized water and the like are used as raw materials and are uniformly mixed according to a certain proportion and sequence to prepare silver paste paint (water-based acrylic aluminum powder paint); then, uniformly coating the water-based acrylic aluminum powder paint on the surface of the cold end part of the silicon-carbon rod; finally, the aluminum-coated layer is obtained by natural drying or baking.

(1) The water-based acrylic aluminum powder paint is mainly prepared from the following raw materials in percentage by weight: the paint comprises metal aluminum powder, acrylic emulsion, a dispersing agent, a defoaming agent, a leveling agent, a thickening agent and deionized water.

(2) The water-based acrylic aluminum powder paint comprises the following components in percentage by weight: 30.0-45.0 parts of acrylic emulsion, 15.0-20.0 parts of deionized water, 2.5-4.0 parts of dispersing agent, 10.0-25.0 parts of cosolvent, 35.0-50.0 parts of water-based aluminum powder, 0.1-0.3 part of defoaming agent, 1.0-1.5 parts of thickening agent and 0.1-0.2 part of flatting agent.

(3) The preparation of the water-based acrylic aluminum powder paint comprises the following steps: firstly, adding deionized water, a propylene glycol methyl ether cosolvent and a dispersing agent into aqueous aluminum powder for dispersion to prepare an aluminum paste dispersion liquid; and then adding the acrylic emulsion, deionized water, various auxiliaries and the aluminum paste dispersion liquid into a proportioning pot in a certain sequence according to a formula proportion, uniformly stirring at the rotating speed of 300-400 r/min, and adding a thickening agent when the temperature reaches 30-45 ℃ in the stirring process to prepare the water-based aluminum powder impregnating varnish.

(4) The water-based aluminum paste is characterized in that the aluminum powder particles are in the shape of a rolling body in a geometric shape, are in a shape of a tiny scale and have a thickness of 0.1-1.5 mu m; the particle size distribution of the particles is that the diameter is between 10 and 150 mu m.

(5) The aluminum paste contains 65-70% of aluminum powder and 30-35% of solvent, and comprises floating aluminum paste and non-floating aluminum paste.

(6) In the preparation process of the water-based aluminum powder paint dipping, a dispersing agent for improving the wetting dispersion of aluminum powder and preventing sedimentation and aggregation needs to be added. The wetting dispersant is preferably BYK190 used for a water-based paint system, and the addition amount is 0.1-0.6%.

(7) The prepared water-based acrylic aluminum powder paint is uniformly coated on the surface of the cold end part of the silicon carbide rod, and then the aluminum-coated layer is obtained by natural airing or drying.

(8) The coating method of the water-based acrylic aluminum paint comprises the following steps: cold spraying, dipping, brushing, rolling and the like, and the thickness of the aluminum coating can be controlled by the concentration of the silver paste and the dipping and pulling times or brushing times.

(9) Coating typically goes through several steps: loading, cleaning, dipping (brushing, rolling or spraying) paint, draining paint, drying and unloading. Since the surface of the silicon carbide rod has some foreign matters, it should be properly treated. Generally, the coating is finished by polishing or cleaning by blowing, dipping (brushing, rolling or spraying) the coating, draining and drying.

(10) The coating and drying of the water-based acrylic aluminum powder paint can be carried out naturally, but in order to improve the efficiency, the baking and drying can be carried out, and the baking temperature is preferably 60-100 ℃.

(11) The water-based acrylic aluminum paint needs to be added with a leveling agent, so that the problem of sagging of the aluminum paint can be avoided, and a smooth aluminum-coated layer is ensured to be formed.

The embodiments of the present invention have been described in detail, but the description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention. Any modification, equivalent replacement, and improvement made within the scope of the application of the present invention should be included in the protection scope of the present invention.