A method for etching grains of pure aluminum

Abstract

The present application relates to a kind of grain etching methods of pure aluminum, specifically relates to surface treatment field, the grain etching method includes: the observation surface of pure aluminum material sample is sequentially carried out copper salt solution treatment, first cleaning and dilute nitric acid treatment;The copper salt solution treatment is carried out at least 3 times;Single copper salt solution treatment time is greater than dilute nitric acid treatment time.The grain etching method provided by the present application, by the design of etching process, with the synergistic cooperation of copper salt solution treatment and dilute nitric acid treatment, can realize the efficient etching of pure aluminum, and the grain boundary can be observed after etching.

Description

Technical Field

[0001] This invention relates to the field of surface treatment, and more specifically to a method for grain etching of pure aluminum. Background Technology

[0002] Pure aluminum has excellent forming and processing characteristics, high corrosion resistance, good weldability and electrical conductivity, and is often used in the semiconductor field. Pure aluminum is a material that cannot be strengthened by heat treatment. The quality of its microstructure depends on the size, morphology and distribution of the grains. Therefore, it is of great significance to understand the size, morphology and distribution of the grains in a timely manner.

[0003] Currently, in order to obtain the required properties of pure aluminum and analyze the mechanism of material property changes, it is necessary to perform grain size analysis on the material. Etching agents are commonly used to etch pure aluminum to form visible grain boundaries on the surface of pure aluminum, which facilitates the evaluation and analysis of the grain size of the material.

[0004] For example, CN118807555A discloses a pure aluminum grain size etchant preparation device, including a preparation device body, a feed cylinder and a discharge pipe. The bottom of the preparation device body is provided with a drive motor, and the output end of the drive motor passes through the preparation device body and is connected to a drive shaft. The outer side wall of the drive shaft is provided with stirring plates that are fixedly distributed at equal intervals. The feed cylinder is fixedly distributed at both ends of the top of the preparation device body and has a symmetrical structure. The top of the preparation device body is provided with a feeding port, and the feed cylinder is fixedly located at the upper end of the feeding port. The top of the feed cylinder is fixedly provided with a feeding port, and the top of the feeding port is fixedly provided with a feeding outlet. The discharge pipe is fixedly located at the bottom side of the preparation device body.

[0005] CN106498399A discloses a pure aluminum grain-size etchant and its preparation method, as well as a corrosion development method. This pure aluminum grain-size etchant consists of the following components: 5-7 g K₂CrO₄, 6-10 mL nitric acid, 1 mL saturated aqueous solution of picric acid, 0.4-0.6 mL hydrofluoric acid, 4-8 mL hydrochloric acid, and 18-22 mL water. The pure aluminum matrix is ​​a single α-solid solution with different phases, which forms grain boundaries after corrosion.

[0006] However, existing corrosion processes still suffer from poor corrosion effect and low corrosion efficiency, which is not conducive to achieving efficient detection of pure aluminum grains. Summary of the Invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide a grain corrosion method for pure aluminum to solve the defects of low corrosion efficiency and poor corrosion effect in the current pure aluminum corrosion.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] This invention provides a method for grain etching of pure aluminum, the grain etching method comprising:

[0010] The observation surfaces of the pure aluminum samples were sequentially treated with copper salt solution, first cleaning, and dilute nitric acid.

[0011] The copper salt solution treatment shall be performed at least three times;

[0012] The time required for a single copper salt solution treatment is greater than the time required for the dilute nitric acid treatment.

[0013] The grain etching method provided by this invention, through the design of the etching process and the synergistic effect of copper salt solution treatment and dilute nitric acid treatment, can achieve efficient etching of pure aluminum, and obvious grain boundaries can be observed after etching.

[0014] As a preferred embodiment of the present invention, the mass concentration of the copper salt solution used in the copper salt solution treatment is 40-60%.

[0015] As a preferred embodiment of the present invention, the processing time for a single copper salt solution is 15-20 seconds.

[0016] As a preferred technical solution of the present invention, the first cleaning method includes: water washing and / or alcohol washing.

[0017] Preferably, the first cleaning time is 10-60 seconds.

[0018] As a preferred embodiment of the present invention, the mass concentration of the dilute nitric acid used in the dilute nitric acid treatment is 40-45%.

[0019] As a preferred embodiment of the present invention, the dilute nitric acid treatment time is 5-10 seconds.

[0020] As a preferred technical solution of the present invention, a constant voltage current is applied to the pure aluminum sample during the copper salt solution treatment.

[0021] As a preferred embodiment of the present invention, the voltage of the constant voltage current is 5-10V.

[0022] As a preferred technical solution of the present invention, a constant current is applied to the pure aluminum sample during the dilute nitric acid treatment.

[0023] As a preferred embodiment of the present invention, the current density of the constant current is 0.1-0.5 A / cm². 2 .

[0024] Compared with existing technical solutions, the present invention has the following beneficial effects:

[0025] (1) The grain etching method provided by the present invention, with the help of the synergistic combination of copper salt solution treatment and dilute nitric acid treatment, can observe obvious grain boundaries after etching, and at the same time significantly reduces the etching time, which is conducive to the rapid preparation of etched samples, thereby improving the grain detection efficiency.

[0026] (2) The grain corrosion method provided by the present invention can further enhance the corrosion effect by applying constant current and constant voltage current to copper salt solution treatment and dilute nitric acid treatment respectively, making the grain boundaries after corrosion clearer and more conducive to the analysis of pure aluminum grains. Attached Figure Description

[0027] Figure 1 This is a corrosion diagram of the pure aluminum sample from Example 1 of the present invention;

[0028] Figure 2 This is a corrosion diagram of the pure aluminum sample from Example 2 of the present invention;

[0029] Figure 3 This is a corrosion diagram of the pure aluminum sample from Example 3 of the present invention;

[0030] Figure 4 This is a corrosion diagram of the pure aluminum sample from Example 4 of the present invention;

[0031] Figure 5 This is a corrosion diagram of the pure aluminum sample from Example 5 of the present invention;

[0032] Figure 6 This is a corrosion diagram of the pure aluminum sample from Example 6 of the present invention;

[0033] Figure 7 This is a corrosion diagram of the pure aluminum sample from Example 7 of the present invention;

[0034] Figure 8 This is a corrosion diagram of the pure aluminum sample in Example 8 of the present invention;

[0035] Figure 9 This is a corrosion diagram of the pure aluminum sample from Example 9 of the present invention;

[0036] Figure 10 This is a corrosion diagram of the pure aluminum sample in Comparative Example 1 of this invention;

[0037] Figure 11 This is a corrosion diagram of the pure aluminum sample in Comparative Example 2 of this invention;

[0038] Figure 12 This is a corrosion diagram of the pure aluminum sample in Comparative Example 3 of this invention;

[0039] Figure 13 This is a corrosion diagram of the pure aluminum sample in Comparative Example 4 of this invention;

[0040] Figure 14This is a corrosion diagram of the pure aluminum sample in Comparative Example 5 of this invention;

[0041] Figure 15 This is a corrosion diagram of the pure aluminum sample in Comparative Example 6 of this invention.

[0042] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0043] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0044] Currently, in order to obtain the desired properties of pure aluminum and analyze the mechanism of material property changes, grain size analysis is required. Etching agents are commonly used to etch pure aluminum to form visible grain boundaries on the surface, facilitating the evaluation and analysis of grain size. However, existing etching processes still suffer from poor etching effect and low etching efficiency, hindering efficient detection of pure aluminum grains. Therefore, this invention, through the design of the etching process, utilizes the synergistic effect of copper salt solution treatment and dilute nitric acid treatment to achieve highly efficient etching of pure aluminum. After etching, clear grain boundaries can be observed, as detailed below:

[0045] I. This embodiment provides a method for grain etching of pure aluminum, the grain etching method comprising:

[0046] The observation surfaces of the pure aluminum samples were sequentially treated with copper salt solution, first cleaning, and dilute nitric acid.

[0047] The copper salt solution treatment shall be performed at least three times;

[0048] The time required for a single copper salt solution treatment is greater than the time required for the dilute nitric acid treatment.

[0049] In this invention, the purity of the pure aluminum material is ≥99.99%.

[0050] The copper salt solution used in the copper salt solution treatment has a mass concentration of 40-60%, for example, it can be 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58% or 60%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0051] In this invention, the copper salt used in the copper salt solution is selected as a soluble copper salt, including copper sulfate, copper nitrate, copper chloride, etc.

[0052] The processing time for a single copper salt solution treatment is 15-20 seconds, for example, it can be 15 seconds, 15.5 seconds, 16 seconds, 16.5 seconds, 17 seconds, 17.5 seconds, 18 seconds, 18.5 seconds, 19 seconds, 19.5 seconds or 20 seconds, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0053] The first cleaning method includes: water washing and / or alcohol washing.

[0054] In this invention, alcohol washing refers to cleaning the sample with alcohol or alcohol solution (alcohol + water) commonly used in the cleaning field. The cleaning process is carried out at room temperature of 10-30°C. The alcohol can be selected as ethanol and / or glycerol, etc. The room temperature of 10-30°C can be, for example, 10°C, 12°C, 14°C, 16°C, 18°C, 20°C, 22°C, 24°C, 26°C, 28°C or 30°C, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0055] The first cleaning time is 10-60 seconds, for example, it can be 10 seconds, 15 seconds, 20 seconds, 25 seconds, 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds or 60 seconds, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0056] The mass concentration of the dilute nitric acid used in the dilute nitric acid treatment is 40-45%, for example, it can be 40%, 40.5%, 41%, 41.5%, 42%, 42.5%, 43%, 43.5%, 44%, 44.5% or 45%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0057] The dilute nitric acid treatment time is 5-10 seconds, for example, it can be 5 seconds, 5.5 seconds, 6 seconds, 6.5 seconds, 7 seconds, 7.5 seconds, 8 seconds, 8.5 seconds, 9 seconds, 9.5 seconds or 10 seconds, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0058] In the copper salt solution treatment, a constant voltage current is applied to the pure aluminum sample.

[0059] The voltage of the constant voltage current is 5-10V, such as 5V, 5.5V, 6V, 6.5V, 7V, 7.5V, 8V, 8.5V, 9V, 9.5V or 10V, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0060] In the dilute nitric acid treatment, a constant current is applied to the pure aluminum sample.

[0061] The constant current has a current density of 0.1-0.5 A / cm². 2 For example, it could be 0.1 A / cm 2 0.14A / cm 2 0.18A / cm 2 0.22A / cm 2 0.26A / cm 2 0.3A / cm 2 0.34A / cm 2 0.38A / cm 2 0.42A / cm 2 0.46A / cm 2 Or 0.5A / cm 2 The values ​​may include, but are not limited to, the listed values; other unlisted values ​​within this range also meet the requirements.

[0062] In this invention, after treatment with dilute nitric acid, the sample can be further cleaned and dried to obtain a clean sample for observation. The specific method should be chosen according to the detection requirements in this field.

[0063] II. To illustrate the corrosion effect achievable by the grain etching method for pure aluminum provided by this invention, the following example is used for explanation:

[0064] Example 1

[0065] This embodiment provides a method for grain etching of pure aluminum, the grain etching method comprising:

[0066] The observation surfaces of the pure aluminum samples were sequentially treated with copper salt solution, first cleaning, dilute nitric acid treatment, water washing, and drying.

[0067] The copper salt solution treatment was performed three times.

[0068] The time required for a single copper salt solution treatment is greater than the time required for the dilute nitric acid treatment.

[0069] The purity of pure aluminum is 99.99%;

[0070] The copper salt solution (copper chloride solution) used in the copper salt solution treatment has a mass concentration of 50%, and the treatment time for a single treatment is 18 seconds.

[0071] The first cleaning method is water washing, which takes 30 seconds;

[0072] The dilute nitric acid used in the treatment had a mass concentration of 42% and a treatment time of 8 seconds.

[0073] Example 2

[0074] This embodiment provides a method for grain etching of pure aluminum, the grain etching method comprising:

[0075] The observation surfaces of the pure aluminum samples were sequentially treated with copper salt solution, first cleaning, dilute nitric acid treatment, water washing, and drying.

[0076] The copper salt solution treatment was performed three times.

[0077] The time required for a single copper salt solution treatment is greater than the time required for the dilute nitric acid treatment.

[0078] The purity of pure aluminum is 99.999%;

[0079] The copper salt solution (copper nitrate solution) used in the copper salt solution treatment has a mass concentration of 40%, and the treatment time for a single treatment is 20 seconds.

[0080] The first cleaning method is water washing, which takes 10 seconds;

[0081] The dilute nitric acid used in the treatment has a mass concentration of 45% and a treatment time of 5 seconds.

[0082] During the copper salt solution treatment, a constant voltage current is applied to the pure aluminum sample, and the voltage of the constant voltage current is 10V.

[0083] During the dilute nitric acid treatment, a constant current was applied to the pure aluminum sample, with a current density of 0.1 A / cm². 2 .

[0084] Example 3

[0085] This embodiment provides a method for grain etching of pure aluminum, the grain etching method comprising:

[0086] The observation surfaces of the pure aluminum samples were sequentially treated with copper salt solution, first cleaning, dilute nitric acid treatment, water washing, and drying.

[0087] The copper salt solution treatment was performed four times.

[0088] The time required for a single copper salt solution treatment is greater than the time required for the dilute nitric acid treatment.

[0089] The purity of pure aluminum is 99.99%;

[0090] The copper salt solution (copper chloride solution) used in the copper salt solution treatment has a mass concentration of 60%, and the treatment time for a single treatment is 15 seconds.

[0091] The first cleaning method is ethanol washing, with a time of 60 seconds;

[0092] The mass concentration of the dilute nitric acid used in the dilute nitric acid treatment is 40%, and the time is 10 seconds.

[0093] During the copper salt solution treatment, a constant voltage current is applied to the pure aluminum sample, and the voltage of the constant voltage current is 5V.

[0094] During the dilute nitric acid treatment, a constant current was applied to the pure aluminum sample, with a current density of 0.5 A / cm². 2 .

[0095] Example 4

[0096] The only difference from Example 1 is that: in the copper salt solution treatment, a constant voltage current of 8V is applied to the pure aluminum sample; in the dilute nitric acid treatment, a constant current current of 0.3A / cm³ is applied to the pure aluminum sample. 2 .

[0097] Example 5

[0098] The only difference from Example 4 is that no constant voltage current is applied to the pure aluminum sample during the copper salt solution treatment.

[0099] Example 6

[0100] The only difference from Example 4 is that no constant current is applied to the pure aluminum sample during the dilute nitric acid treatment.

[0101] Example 7

[0102] The only difference from Example 4 is that:

[0103] During the copper salt solution treatment, a constant current was applied to the pure aluminum sample, with a current density of 0.3 A / cm². 2 ;

[0104] During the dilute nitric acid treatment, a constant voltage current of 8V is applied to the pure aluminum sample.

[0105] Example 8

[0106] The only difference from Example 4 is that a constant current was applied to the pure aluminum sample during the copper salt solution treatment, with a current density of 0.3 A / cm². 2 .

[0107] Example 9

[0108] The only difference from Example 4 is that a constant voltage current of 8V is applied to the pure aluminum sample during the dilute nitric acid treatment.

[0109] Comparative Example 1

[0110] The only difference from Example 1 is that no copper salt solution treatment is performed.

[0111] Comparative Example 2

[0112] The only difference from Example 1 is that dilute nitric acid treatment is not performed.

[0113] Comparative Example 3

[0114] The only difference from Example 1 is that the copper salt solution treatment was performed twice.

[0115] Comparative Example 4

[0116] The only difference from Example 1 is that the time for a single copper salt solution treatment is 6 seconds.

[0117] Comparative Example 5

[0118] The only difference from Example 1 is that the copper salt solution is replaced with a potassium chromate solution of the same concentration.

[0119] Comparative Example 6

[0120] The only difference from Example 1 is that dilute nitric acid is replaced with hydrofluoric acid of the same concentration.

[0121] The observation of the crystalline structure of the aluminum materials obtained by corrosion in the above embodiments and comparative examples was carried out based on GB / T6394-2017 "Method for determination of average grain size of metals", and the results are shown in Table 1 below.

[0122] Table 1

[0123]

[0124] As shown in Table 1, the grain etching method provided by the present invention, through the design of the etching process and the synergistic effect of copper salt solution treatment and dilute nitric acid treatment, can achieve efficient etching of pure aluminum. After etching, obvious grain boundaries can be observed. The grain boundaries of the sample obtained after etching are basically continuous, with slight local variations in depth, which does not affect the crystal grade rating. Under the preferred scheme, the grain boundaries are clear and continuous, with good contrast, no over- / under-etching, and uniform.

[0125] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0126] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0127] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for grain etching of pure aluminum, characterized in that, The grain etching method includes: The observation surfaces of the pure aluminum samples were sequentially treated with copper salt solution, first cleaning, and dilute nitric acid. The copper salt solution treatment shall be performed at least three times; The time required for a single copper salt solution treatment is greater than the time required for the dilute nitric acid treatment.

2. The grain etching method as described in claim 1, characterized in that, The mass concentration of the copper salt solution used in the copper salt solution treatment is 40-60%.

3. The grain etching method as described in claim 1, characterized in that, The time for a single copper salt solution treatment is 15-20 seconds.

4. The grain etching method as described in claim 1, characterized in that, The first cleaning method includes: water washing and / or alcohol washing; Preferably, the first cleaning time is 10-60 seconds.

5. The grain etching method as described in claim 1, characterized in that, The mass concentration of the dilute nitric acid used in the dilute nitric acid treatment is 40-45%.

6. The grain etching method as described in claim 1, characterized in that, The dilute nitric acid treatment time is 5-10 seconds.

7. The grain etching method as described in claim 1, characterized in that, A constant voltage current is applied to the pure aluminum sample during the copper salt solution treatment.

8. The grain etching method as described in claim 7, characterized in that, The voltage of the constant voltage current is 5-10V.

9. The grain etching method as described in claim 1, characterized in that, A constant current is applied to the pure aluminum sample during the dilute nitric acid treatment.

10. The grain etching method as described in claim 9, characterized in that, The constant current has a current density of 0.1-0.5 A / cm². 2 .

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