Electrolytic corrosion sample, plastic embedding auxiliary device and sample preparation method

Abstract

The present invention discloses an electrolytic corrosion sample, a plastic embedding auxiliary device and a sample preparation method. The sample is embedded in plastic. There is a circle of continuous conductive material along the circumferential outer surface of the plastic. The conductive material is connected to the sample through a conductor, and the conductor is embedded in the plastic. The plastic embedding auxiliary device includes a conductive, elastic, C-shaped ring body pre-bent into the shape of the letter C and a nickel belt. One end of the nickel belt is connected to the sample, and the other end is connected to the C-shaped ring body. When preparing the electrolytic corrosion sample, an external force is applied to reduce the outer diameter of the C-shaped ring body, and then the C-shaped ring is placed in the steel mold sleeve cavity of the embedding machine. The observation surface of the sample is close to the bottom surface of the steel mold sleeve cavity of the embedding machine, and the external force is removed. Finally, the general plastic embedding process is performed. The present invention solves the problems of difficulty in turning on the power supply and uneven corrosion after conventional plastic embedding samples.

Description

Technical Field

[0001] The invention belongs to the field of experiment and test technology, and in particular relates to an electrolytic corrosion sample, a plastic embedding auxiliary device and a sample preparation method. Background Art

[0002] Electrolytic corrosion is to use the sample as the anode of the circuit, immerse it in a suitable electrolytic corrosion solution, and pass a small current to corrode in order to show the metal microstructure. It is essential to perform electrolytic corrosion after the sample is inlaid and ground, such as electrolytic corrosion to show the grains of materials such as GH3039, GH3030, and GH4169. Since plastic is not conductive, when the sample used for electrolytic corrosion is inlaid in plastic, it is generally adopted to add a certain proportion of copper powder to the inlaid plastic and connect the wire to the sample surface after grinding and polishing. The method of adding copper powder is not conductive at low voltage, and the method of connecting the wire will cause uneven electrolytic corrosion of the tissue in the area near the wire. Summary of the invention

[0003] In order to solve the above technical problems, the present invention aims to provide an electrolytic corrosion sample, a plastic embedding auxiliary device and a sample preparation method to solve the problems of difficulty in conducting power and uneven corrosion after conventional plastic embedding samples.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] An electrolytic corrosion sample comprises a sample which is embedded in plastic. A circle of continuous conductive material is arranged along the circumferential outer surface of the plastic. The conductive material is connected to the sample through a conductor which is embedded in the plastic.

[0006] A plastic inlay auxiliary device for electrolytic corrosion samples, used for the above electrolytic corrosion samples, the plastic inlay auxiliary device comprises:

[0007] A C-shaped ring body, wherein the C-shaped ring body is a conductive, elastic, and pre-bent band structure into a letter C shape, and the sample is located inside an enclosed area formed by the C-shaped ring body;

[0008] When the C-shaped ring body is not subjected to external force, there is a gap between the first end and the second end of the C-shaped ring body. At this time, the maximum outer diameter of the C-shaped ring body is greater than the inner diameter of the steel mold sleeve of the inserting machine;

[0009] When the C-shaped ring body is subjected to an external force and the first end and the second end of the C-shaped ring body are in contact, the maximum outer diameter of the C-shaped ring body is less than or equal to the inner diameter of the steel mold sleeve of the inserting machine;

[0010] A wire, one end of which is connected to the sample, and the other end of which is connected to the C-shaped ring body.

[0011] Furthermore, the first end and the second end are provided with a cylindrical tube structure.

[0012] As an option, the C-shaped ring body is a spring steel strip pre-bent into a letter C shape.

[0013] As an option, the conductive wire is a nickel strip, and the nickel strip is a nickel-plated steel strip.

[0014] As an option, the length of the wire is greater than the inner diameter of the steel mold sleeve of the inserting machine.

[0015] As an option, there are two nickel strips, and the two nickel strips are symmetrically arranged about the sample.

[0016] As an option, the nickel strip is connected to the test specimen and the C-ring body respectively by spot welding.

[0017] A method for preparing an electrolytic corrosion sample, using the above-mentioned plastic inlay auxiliary device, comprises the following steps:

[0018] Step 1: weld one end of the wire to the non-observation surface of the sample, and weld the other end of the wire to the inner surface of the C-shaped ring;

[0019] Step 2: Place the wire, C-shaped ring body and sample into the steel mold sleeve cavity of the embedding machine, wherein the outer diameter of the C-shaped ring body is reduced by squeezing the C-shaped ring body, and then the C-shaped ring body is placed into the steel mold sleeve cavity of the embedding machine, and finally the squeezing force on the C-shaped ring body is removed so that the outer surface of the C-shaped ring body is closely attached to the inner surface of the steel mold sleeve cavity of the embedding machine, and the observation surface of the sample is closely attached to the bottom surface of the steel mold sleeve cavity of the embedding machine;

[0020] Step 3: Perform the plastic mounting process.

[0021] As an option, in step three, the plastic mounting process includes sequentially performing filling, placing in the upper mold and fixing, heating and pressurizing, and taking out the completed plastic mounted sample.

[0022] As an option, the method for preparing the electrolytic corrosion sample further includes grinding, polishing and cleaning the sample after the plastic embedding in step three.

[0023] Since the plastic used for embedding samples is not conductive, there is no better solution for embedding samples in plastic for electrolytic corrosion. Generally, a certain proportion of copper powder is added to the embedding plastic and a wire is connected to the sample surface after grinding and polishing. The method of adding copper powder is not conductive under low voltage, while electrolytic corrosion is generally carried out under low voltage; the method of connecting wires will cause uneven electrolytic corrosion of tissues in the area near the wires.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] (1) The present invention solves the problem of non-conductivity of the sample after plastic embedding. The two nickel strips connected have good conductivity and can provide good support for electrolytic corrosion.

[0026] (2) The C-shaped ring is located on the side wall (circumferential outer surface) of the plastic-mounted specimen, and the electrolytic corrosion of the specimen is uniform in all areas.

[0027] (3) The C-shaped ring body serves as an electrode that connects the sample to the outside world. The electrode area is large and can conduct the sample through contact at different angles, which facilitates electrolytic corrosion operations.

[0028] (4) After the C-shaped ring is loosened (after the external force is removed), it is tightly attached to the inner wall of the steel mold sleeve cavity of the embedding machine. The position of the sample can be adjusted by the welded nickel strip (the length of the nickel strip as a conductor is greater than the inner diameter of the steel mold sleeve cavity of the embedding machine and can be bent), which can provide fixation and adjustment margin for small samples.

[0029] (5) Nickel strips can be spot welded using a portable spot welding machine, which is easy to use.

[0030] (6) The C-shaped ring body is made of spring steel, the nickel strip is made of nickel-plated steel strip, and the spot welding can be completed by a portable spot welding machine, which is low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the plastic embedding auxiliary device of the present invention;

[0032] Figure 2 for Figure 1 A top view of

[0033] In the figure, 1-C-shaped ring; 2-nickel belt; 3-sample. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but it should not be understood that the scope of the subject matter described in the present invention is limited to the following embodiments. Without departing from the above-mentioned technical ideas of the present invention, various modifications, substitutions and changes made according to the common technical knowledge and customary means in the field are included in the scope of the present invention.

[0035] In the present invention, an electrolytic corrosion sample is first designed, including cut GH3039, GH3030, GH4169 and other materials as sample 3, sample 3 is embedded in plastic by an embedding machine, and a circle of continuous conductive material is formed along the circumferential outer surface of the plastic to form a conductive surface, the conductive material is connected to the sample 3 inside the plastic through a conductor, and the conductor is also embedded in the plastic.

[0036] In order to prepare the above electrolytic corrosion specimens, a plastic inlay auxiliary device was used, which was realized by the following technical solution:

[0037] (1) A C-shaped ring body 1 having a diameter slightly larger than the inner diameter of the steel mold sleeve of the embedding machine is made of a spring steel strip;

[0038] (2) There are cylindrical tube structures at both ends of the C-shaped ring body 1 for tweezers or needle-nosed pliers to be inserted;

[0039] (3) Two nickel strips 2 are welded to the two inner walls of the C-shaped ring body 1 as conductors for connecting the sample 3 and the C-shaped ring body 1;

[0040] (4) Before inlaying, the sample 3 is connected to the two nickel strips 2 by spot welding;

[0041] (5) When setting, use tweezers or needle-nosed pliers to compress the diameter of the C-shaped ring body 1. At this time, the diameter of the C-shaped ring body 1 is smaller than the inner diameter of the steel mold sleeve of the setting machine;

[0042] (6) Place the C-shaped ring 1 at the bottom of the steel mold cavity of the mounting machine, loosen the tweezers or needle-nosed pliers at a distance of about 2 mm from the bottom, and the C-shaped ring 1 will be closely attached to the inner wall of the steel mold cavity of the mounting machine. Adjust the specimen 3 so that the observation surface faces downward and is attached to the lower mold of the mounting machine;

[0043] (7) Carry out the remaining process of general mounting, i.e. filling - placing in the upper mold and fixing - heating and pressurizing - taking out the sample;

[0044] (8) The plastic-embedded sample is ground and polished. During electrolytic corrosion, the anode of the power supply is brought into contact with the C-shaped ring body 1 to conduct the sample 3 for electrolytic corrosion.

[0045] Example 1

[0046] Combine the following Figure 1 and Figure 2 To further describe the electrolytic corrosion sample preparation method of the present invention, this embodiment is applicable to the steel mold sleeve cavity of the embedding machine with an inner diameter of 30 mm, and the specific steps are as follows:

[0047] (1) A C-shaped ring body 1 with a diameter of 32 mm is made of 65Mn spring steel strip, and the opening of the C-shaped ring body 1 is 90° (i.e. Figure 2 The angle between the first end and the second end of the C-shaped ring body 1 and the center line of the C-shaped ring body 1 is 90°. Figure 2 The solid line in the middle is the appearance of the C-shaped ring body 1 after the external force is removed, and the dotted line is the appearance of the C-shaped ring body 1 when the external force is applied). The C-shaped ring body 1 is a steel strip with a height of 10 mm and a thickness of 0.15 mm.

[0048] (2) There is a cylindrical tube with a diameter of 4 mm at each end of the C-shaped ring body 1.

[0049] (3) Two nickel strips 2 are welded to the two inner walls of the C-shaped ring body 1. The nickel strips 2 are nickel-plated steel strips. The nickel strips 2 are 3 mm wide and 0.1 mm thick. After welding, the nickel strips 2 are 18 mm long.

[0050] (4) Before inlaying, the left and right sides of the sample 3 were spot welded to the two nickel strips 2 using a portable spot welding machine.

[0051] (5) When setting, use tweezers or needle-nosed pliers to insert into the cylindrical tube to compress the diameter of the C-shaped ring body 1. At this time, the diameter of the C-shaped ring body 1 is about 28 mm.

[0052] (6) Place the C-shaped ring 1 at the bottom of the steel mold sleeve cavity of the embedding machine. Release the tweezers or needle-nosed pliers at a distance of about 2 mm from the bottom. The C-shaped ring 1 will be tightly attached to the inner wall of the steel mold sleeve cavity of the embedding machine. Bend the nickel strip 2 appropriately and adjust the sample 3 so that its observation side faces downward and is attached to the lower mold of the embedding machine.

[0053] (7) Carry out the remaining process of general mounting, i.e. filling - placing in the upper mold and fixing - heating and pressurizing - taking out the sample.

[0054] (8) Grind, polish and clean the mounted sample, place the power anode in contact with the C-shaped ring body 1 to conduct the sample, and select a suitable electrolytic etching solution for electrolytic etching.

Claims

1. A plastic embedding auxiliary device for electrolytic corrosion specimens, characterized in that: The electrolytic corrosion specimen comprises a specimen (3), wherein the specimen (3) is embedded in plastic, a circle of continuous conductive material is provided along the circumferential outer surface of the plastic, the conductive material is connected to the specimen (3) via a conductor, and the conductor is embedded in the plastic; Plastic mounting aids include: A C-shaped ring body (1), wherein the C-shaped ring body (1) is a conductive, elastic, and pre-bent ribbon structure into the shape of the letter C, and the sample (3) is located inside an enclosed area formed by the C-shaped ring body (1); When the C-shaped ring body (1) is not subjected to an external force, there is a gap between the first end and the second end of the C-shaped ring body (1), and at this time, the maximum outer diameter of the C-shaped ring body (1) is greater than the inner diameter of the steel mold sleeve of the embedding machine; When the C-shaped ring body (1) is subjected to an external force and the first end and the second end of the C-shaped ring body (1) are in contact, the maximum outer diameter of the C-shaped ring body (1) is less than or equal to the inner diameter of the steel mold sleeve cavity of the inserting machine; A wire, one end of which is connected to the sample (3), and the other end of which is connected to the C-shaped ring body (1).

2. The plastic embedding auxiliary device for electrolytic corrosion specimens according to claim 1, characterized in that: The first end and the second end are provided with a cylindrical tube structure.

3. The plastic embedding auxiliary device for electrolytic corrosion specimens according to claim 1, characterized in that: The C-shaped ring body (1) is a spring steel strip pre-bent into the shape of the letter C.

4. The plastic embedding auxiliary device for electrolytic corrosion specimens according to claim 1, characterized in that: The conductive wire is a nickel strip (2), and the nickel strip (2) is a nickel-plated steel strip.

5. The plastic embedding auxiliary device for electrolytic corrosion specimens according to claim 4, characterized in that: There are two nickel strips (2), and the two nickel strips (2) are symmetrically arranged with respect to the sample (3).

6. The plastic embedding auxiliary device for electrolytic corrosion specimens according to claim 4, characterized in that: The nickel strip (2) is connected to the sample (3) and the C-shaped ring body (1) respectively by spot welding.

7. A method for preparing an electrolytic corrosion sample, characterized in that: The plastic embedding auxiliary device according to claim 1 comprises the following steps: Step 1: welding one end of the wire to the non-observation surface of the sample (3), and welding the other end of the wire to the inner surface of the C-shaped ring body (1); Step 2, placing the wire, the C-shaped ring body (1) and the sample (3) into the cavity of the steel mold sleeve of the mounting machine, wherein the outer diameter of the C-shaped ring body (1) is reduced by squeezing the C-shaped ring body (1), and then the C-shaped ring body (1) is placed into the cavity of the steel mold sleeve of the mounting machine, and finally the squeezing force on the C-shaped ring body (1) is removed so that the outer surface of the C-shaped ring body (1) is in close contact with the inner surface of the cavity of the steel mold sleeve of the mounting machine, and the observation surface of the sample (3) is in close contact with the bottom surface of the cavity of the steel mold sleeve of the mounting machine; Step 3: Perform the plastic mounting process.

8. The method for preparing an electrolytic corrosion sample according to claim 7, characterized in that: In step three, the plastic mounting process includes the following steps: filling, placing in the upper mold and fixing, heating and pressurizing, and taking out the completed plastic mounted sample.

9. The method for preparing an electrolytic corrosion sample according to claim 7, characterized in that: It also includes grinding, polishing and cleaning the sample that has been plastic-mounted in step three.

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