阅读说明：本技术 一种铝合金表面黑色陶瓷膜及其制备方法 (Aluminum alloy surface black ceramic membrane and preparation method thereof ) 是由 房爱存 赵树辉 房昊伟 赵忠 孙锁柱 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种铝合金表面黑色陶瓷膜,制备铝合金表面黑色陶瓷膜的电解液包括：磷酸盐10-20g/L,硅酸盐3-10g/L,草酸盐10-20g/L,柠檬酸盐3-10g/L,调整剂30-50ml/L和去离子水。本发明中的铝合金表面黑色陶瓷膜,致密均匀,黑色度高、耐磨、耐蚀性好,电解液不含环保限制元素,无毒无害,使用周期长,可长达1-2年,绿色环保,制备工艺简单,成本低。本发明还公开了一种铝合金表面黑色陶瓷膜的制备方法。(The invention discloses a black ceramic membrane on the surface of aluminum alloy, and an electrolyte for preparing the black ceramic membrane on the surface of aluminum alloy comprises: 10-20g/L of phosphate, 3-10g/L of silicate, 10-20g/L of oxalate, 3-10g/L of citrate, 30-50ml/L of regulator and deionized water. The black ceramic membrane on the surface of the aluminum alloy is compact and uniform, has high blackness, good wear resistance and corrosion resistance, contains no environmental restriction elements, is nontoxic and harmless, has a long service life which can be up to 1-2 years, is green and environment-friendly, and has a simple preparation process and low cost. The invention also discloses a preparation method of the black ceramic membrane on the surface of the aluminum alloy.)

1. The utility model provides an aluminum alloy surface black ceramic membrane which characterized in that, the electrolyte of preparation aluminum alloy surface black ceramic membrane includes: 10-20g/L of phosphate, 3-10g/L of silicate, 10-20g/L of oxalate, 3-10g/L of citrate, 30-50ml/L of regulator and deionized water.

2. The aluminum alloy surface black ceramic film according to claim 1, wherein the modifier is copper pyrophosphate, potassium pyrophosphate and water in a ratio of 1: 3-5: 100, and (3) preparing an aqueous solution.

3. The aluminum alloy surface black ceramic film according to claim 1, wherein the phosphate is sodium polyphosphate or sodium hexametaphosphate; the silicate is sodium silicate; the oxalate is titanium potassium oxalate or titanium ammonium oxalate; the citrate is sodium citrate.

4. A method for preparing a black ceramic membrane on the surface of an aluminum alloy is characterized by comprising the steps of preparing an electrolyte according to the proportion in any one of claims 1 to 3;

cleaning an aluminum alloy object;

putting the cleaned aluminum alloy object into electrolyte for oxidation treatment;

and (5) washing and airing the oxidized aluminum alloy object.

5. The method for preparing the black ceramic membrane on the surface of the aluminum alloy according to claim 4, wherein the step of preparing the electrolyte is to add 10-20g/L of phosphate into deionized water and stir until the phosphate is completely dissolved; then adding 3-10g/L sodium silicate and stirring until the sodium silicate is completely dissolved; adding 10-20g/L oxalate, and stirring until the oxalate is completely dissolved; adding 3-10g/L of citrate, and stirring until the citrate is completely dissolved; adding 30-50ml/L of regulator; standing for a preset time for later use.

6. The method according to claim 5, wherein the predetermined period of time is 8 hours or more.

7. The method for preparing the black ceramic membrane on the surface of the aluminum alloy as claimed in claim 4, wherein the step of cleaning the aluminum alloy object is to clean oil stains and floating dust on the surface of the aluminum alloy object by using a cleaning tank.

8. The method for preparing the black ceramic membrane on the surface of the aluminum alloy according to claim 4, wherein the aluminum alloy object after being cleaned is placed in electrolyte for oxidation treatment, specifically, the aluminum alloy object is hung on an anode copper bar of an oxidation tank after being clamped, and a stainless steel plate in the oxidation tank is connected with a cathode;

the temperature of the electrolyte of the oxidation tank is ensured to be maintained at 20-30 ℃ by a refrigeration system;

setting electric parameters and average current of 1-1.5A/dm²Setting the duty ratio to be 3-20%, the frequency to be 500-600Hz, and the voltage to be controlled to be 500-620V.

9. The method according to claim 8, wherein the electrical parameter further comprises an oxidation time, and the oxidation time is related to the thickness of the black ceramic film on the surface of the aluminum alloy.

10. The method according to claim 9, wherein the oxidation time is 10-50 minutes.

Technical Field

The invention relates to the technical field of light metal surface modification, in particular to a black ceramic membrane on the surface of aluminum alloy and a preparation method thereof.

Background

In view of the characteristics of good corrosion resistance, wear resistance, high insulating property and the like of the black ceramic membrane, the black ceramic membrane is widely applied to the industries of aerospace, aviation, war industry, machinery, automobiles, traffic and the like.

In recent years, micro-arc oxidation technology is utilized in the industry to prepare wear-resistant and corrosion-resistant ceramic oxide films on the surfaces of light metals such as aluminum, magnesium, titanium and the like, so that the application range of the light metals is greatly expanded.

In the prior art, the method for preparing the black oxide film on the surface of the aluminum alloy generally comprises alkali washing, acid washing, washing with deionized water and absolute ethyl alcohol, drying in the sun, and then electrolyzing, wherein the electrolyte is mainly composed of 140-180 g/L H₂SO₄And (4) forming. The aluminum alloy workpiece after the pretreatment is used as an anode, the graphite plate is used as a cathode, the power supply is a direct-current voltage-stabilizing and current-stabilizing power supply, and the adopted parameters comprise: under the normal temperature and constant voltage mode, the voltage is 14-18V, and the electrolysis time is 20-40 min. The coloring liquid comprises 50-70 g/L NiSO₄5-10 g/L MgSO₄And 20-40 g/L of CH₃COOH. The secondary electrolysis adopts the aluminum alloy workpiece after the primary electrolysis as an anode, the graphite plate as a cathode, and the power supply as a direct current voltage-stabilizing and current-stabilizing power supply, and the adopted parameters comprise: the current density is 1.2-2.0A/dm under the constant current mode at the temperature of 28-32 DEG C²The electrolysis time is 60-90 s, secondary electrolysis is needed in the technical process, and the whole process is complicated.

The black ceramic film on the surface of the aluminum alloy has the characteristics of no light reflection, wear resistance, corrosion resistance and the like, and is well applied to the fields of optics, firearms and other individual weapons. At present, the electrolyte for preparing the black ceramic membrane on the surface of the aluminum alloy contains a highly toxic ammonium metavanadate substance which has low solubility at normal temperature, is easy to decompose at high temperature and is easy to separate out at low temperature. The electrolyte has poor stability and short effective period, generally one month, and the use and discharge of the electrolyte can cause great pollution to the environment.

Therefore, it is necessary to develop an environmentally friendly and long-lasting black ceramic film on the surface of aluminum alloy.

Disclosure of Invention

Therefore, the invention provides an aluminum alloy surface black ceramic film and a preparation method thereof, and aims to solve the problem that the use and discharge of electrolyte for preparing the aluminum alloy surface black ceramic film in the prior art can cause great pollution to the environment.

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

according to the invention, the electrolyte for preparing the black ceramic film on the surface of the aluminum alloy comprises: 10-20g/L of phosphate, 3-10g/L of silicate, 10-20g/L of oxalate, 3-10g/L of citrate, 30-50ml/L of regulator and deionized water.

Further, the regulator is copper pyrophosphate, potassium pyrophosphate and water according to the weight ratio of 1: 3-5: 100, and (3) preparing an aqueous solution.

Further, the phosphate is sodium polyphosphate or sodium hexametaphosphate; the silicate is sodium silicate; the oxalate is titanium potassium oxalate or titanium ammonium oxalate; the citrate is sodium citrate.

The invention also provides a preparation method of the black ceramic membrane on the surface of the aluminum alloy, which comprises the steps of preparing electrolyte according to the above mixture ratio;

cleaning an aluminum alloy object;

putting the cleaned aluminum alloy object into electrolyte for oxidation treatment;

and (5) washing and airing the oxidized aluminum alloy object.

Further, preparing electrolyte, specifically, adding 10-20g/L phosphate into deionized water, and stirring until the phosphate is completely dissolved; then adding 3-10g/L sodium silicate and stirring until the sodium silicate is completely dissolved; adding 10-20g/L oxalate, and stirring until the oxalate is completely dissolved; adding 3-10g/L of citrate, and stirring until the citrate is completely dissolved; adding 30-50ml/L of regulator; standing for a preset time for later use.

Further, the preset time is 8 hours or more.

Further, the aluminum alloy object is cleaned by adopting a cleaning tank to clean oil stains and floating dust on the surface of the aluminum alloy object.

Further, putting the cleaned aluminum alloy article into electrolyte for oxidation treatment, specifically, hanging the aluminum alloy article on an anode copper bar of an oxidation tank after the aluminum alloy article is clamped, and connecting a stainless steel plate in the oxidation tank with a cathode;

the temperature of the electrolyte of the oxidation tank is ensured to be maintained at 20-30 ℃ by a refrigeration system;

setting electric parameters and average current of 1-1.5A/dm²Setting the duty ratio to be 3-20%, the frequency to be 500-600Hz, and the voltage to be controlled to be 500-620V.

Further, the electrical parameters also comprise oxidation time, and the length of the oxidation time is related to the thickness of the black ceramic film on the surface of the aluminum alloy.

Further, the oxidation time is 10-50 minutes.

The invention has the following advantages:

the black ceramic membrane on the surface of the aluminum alloy is compact and uniform, has high blackness, good wear resistance and corrosion resistance, contains no environmental restriction elements, is nontoxic and harmless, has a long service life which can be up to 1-2 years, is green and environment-friendly, and has a simple preparation process and low cost.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

The structures, ratios, sizes, and the like shown in the present specification are only used for matching with the contents disclosed in the specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions that the present invention can be implemented, so that the present invention has no technical significance, and any structural modifications, changes in the ratio relationship, or adjustments of the sizes, without affecting the effects and the achievable by the present invention, should still fall within the range that the technical contents disclosed in the present invention can cover.

FIG. 1 is a flow chart illustrating a method for preparing a black ceramic film on an aluminum alloy surface according to an exemplary embodiment;

FIG. 2 is a surface topography of a black ceramic film on an aluminum alloy surface according to an exemplary embodiment.

Detailed Description

The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

According to a first aspect of the embodiments of the present invention, there is provided an aluminum alloy surface black ceramic film, where the electrolyte for preparing the aluminum alloy surface black ceramic film includes: 10-20g/L of phosphate, 3-10g/L of silicate, 10-20g/L of oxalate, 3-10g/L of citrate, 30-50ml/L of regulator and deionized water, wherein the regulator is M-CU.

The regulator is copper pyrophosphate, potassium pyrophosphate and water according to the weight ratio of 1: 3-5: 100, and (3) preparing an aqueous solution.

The phosphate is sodium polyphosphate or sodium hexametaphosphate; the silicate is sodium silicate; the oxalate is titanium potassium oxalate or titanium ammonium oxalate; the citrate is sodium citrate.

The electrolyte disclosed by the invention does not contain environment-friendly limiting elements, is non-toxic and harmless, has a long service cycle which can be as long as 1-2 years, is green and environment-friendly, is black after being electrolyzed on the surface of an aluminum alloy, and has the characteristics of easiness in dissolution during preparation, difficulty in volatilization during use, safety and environmental friendliness during discharge and the like compared with the electrolyte adopting vanadate in the prior art.

According to a second aspect of the embodiments of the present invention, there is also provided a method for preparing a black ceramic film on an aluminum alloy surface, as shown in fig. 1, including:

s1, preparing electrolyte according to a specific ratio;

s2, cleaning the aluminum alloy object;

s3, putting the cleaned aluminum alloy article into electrolyte for oxidation treatment;

and S4, washing and airing the oxidized aluminum alloy article.

Preparing electrolyte, namely adding 10-20g/L phosphate into deionized water, and stirring until the phosphate is completely dissolved; then adding 3-10g/L sodium silicate and stirring until the sodium silicate is completely dissolved; adding 10-20g/L oxalate, and stirring until the oxalate is completely dissolved; adding 3-10g/L of citrate, and stirring until the citrate is completely dissolved; adding 30-50ml/L of regulator; standing for a preset time for later use. The preset time is 8 hours or more.

The aluminum alloy object is cleaned by adopting a cleaning tank to clean oil stains and floating dust on the surface of the aluminum alloy object.

Putting the cleaned aluminum alloy article into electrolyte for oxidation treatment, namely hanging the aluminum alloy article on an anode copper bar of an oxidation tank after the aluminum alloy article is clamped, and connecting a stainless steel plate in the oxidation tank with a cathode;

the temperature of the electrolyte in the oxidation tank is ensured to be maintained at 20-30 ℃ by a refrigeration system, and the temperature of the electrolyte is prevented from being too high or too low.

Setting electric parameters and average current of 1-1.5A/dm²Setting the duty ratio to be 3-20%, the frequency to be 500-600Hz, and the voltage to be controlled to be 500-620V.

The electrical parameters further comprise oxidation time, and the length of the oxidation time is related to the thickness of the black ceramic film on the surface of the aluminum alloy. The oxidation time is 10-50 minutes.

The invention is illustrated below in specific experiments.

Example 1

(1) Preparing an electrolyte: adding 20g/L sodium polyphosphate into deionized water, stirring until the sodium polyphosphate is completely dissolved, and then sequentially adding 5g/L sodium silicate, 15g/L titanium potassium oxalate and 3g/L sodium citrate, and stirring until the sodium polyphosphate is completely dissolved; finally, the modifier M-CU30ml/L was added, and the mixture was stirred while adding. Standing for 8h for use.

(2) Preparing an aluminum alloy test piece with the specification of 100 x 50 x 2mm, deburring, degreasing and washing.

(3) Putting the aluminum alloy object into an oxidation tank, and connecting a cathode and an anode.

(4) In a ratio of 1.2A/dm²Setting an average current; the duty ratio is controlled at 3%, the frequency is controlled at 500Hz, the oxidation termination voltage is controlled at 600V, and the oxidation time is 20min, so that the black compact black ceramic membrane with the average thickness of 25 mu m can be obtained.

The measurement result shows that the black ceramic film on the surface of the aluminum alloy has good blackness and high hardness, and the average hardness reaches HV 914; the neutral salt spray test can reach 1000 h.

Example 2

(1) Preparing an electrolyte: adding 15g/L sodium hexametaphosphate into 100L deionized water, stirring until the sodium hexametaphosphate is completely dissolved, and then sequentially adding 8g/L sodium silicate, 20g/L titanium ammonium oxalate and 5g/L sodium citrate, and stirring until the sodium hexametaphosphate is completely dissolved; finally, the modifier M-CU40ml/L was added, and the mixture was stirred while adding. Standing for 8h for use.

(2) Prepared to have a surface area of about 5dm²And (5) washing the aluminum alloy object with water.

(3) Putting the aluminum alloy object into an oxidation tank, and connecting a cathode and an anode.

(4) In a ratio of 1.5A/dm²Setting an average current; the duty ratio is controlled to be 4%; controlling the frequency at 500 Hz; the oxidation termination voltage is controlled at 620V; the oxidation time was 25 min. An average of 28 μm black ceramic oxide film was obtained.

The measurement result shows that the black ceramic film on the surface of the aluminum alloy has good blackness and high hardness, and the average hardness reaches HV 1067; the neutral salt spray test can reach 1000 h.

The longer the oxidation time is, the thicker the thickness of the black ceramic film on the surface of the aluminum alloy is, and the oxidation time can be determined according to the needs in the practical application process, such as the oxidation time is 30 min.

Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.