A method for preparing a low conductivity metal powder EBSD detection sample with fine grains

Abstract

The application relates to a preparation method of an EBSD detection sample of low-conductivity metal powder with fine grains, and particularly relates to a preparation method of an EBSD detection sample of low-conductivity metal powder with fine grains. The application aims at solving the problems of poor conductivity and low calibration rate of the prepared EBSD sample of titanium alloy powder and the like with fine grains and poor conductivity. The method comprises the following steps: S1, preparing a block sample from the powder; S2, sticking the metal powder on a copper block with good conductivity by using silver glue; and S3, polishing and etching to complete the preparation. The application is used for EBSD detection.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of an EBSD detection sample of low-conductivity metal powder with fine grains. BACKGROUND

[0002] Electron backscatter diffraction (EBSD) is an important material organization characterization method, which can obtain information such as grain size and grain orientation of a material. At present, reported powder EBSD sample preparation methods mainly include a conductive resin hot inlay method and a pressing sintering method, and the methods are mainly aimed at metal powder with coarse grains and good conductivity, and no related report about the EBSD sample preparation of fine-grain low-conductivity metal powder is found. EBSD analysis has a high requirement on the conductivity of a sample, but the EBSD samples prepared by the above methods have poor conductivity, which can further reduce the conductivity of titanium alloy powder, magnesium alloy powder and composite material powder with poor conductivity, and thus EBSD analysis cannot be performed. Meanwhile, the high temperature in the sintering process can change the organization of the powder, and thus the original organization information of the powder cannot be measured. SUMMARY

[0003] The application provides a preparation method of an EBSD detection sample of low-conductivity metal powder with fine grains.

[0004] The preparation method of the EBSD detection sample of low-conductivity metal powder with fine grains is specifically performed according to the following steps.

[0005] I. A copper block is prepared by wire cutting;

[0006] II. The measured surface of the copper block is polished smooth by using sandpaper to obtain a polished copper block;

[0007] III. Fine-grain low-conductivity metal powder is mixed with silver glue to obtain a mixed solution;

[0008] IV. The mixed solution is evenly applied to the measured surface of the polished copper block, and then the copper block is placed in a ventilated place for air drying for 1-2 hours, and then the powder section is polished by using sandpaper to obtain a polished sample;

[0009] V. SiO2 colloidal polishing liquid and H2O2 solution are mixed to configure an EBSD sample polishing liquid;

[0010] VI. The measured surface of the polished sample is polished by using a polishing cloth on a polishing disc, and the EBSD sample polishing liquid is slowly added to the polishing cloth during polishing, and after the measured surface of the sample is polished without scratches, HF solution is used for etching treatment;

[0011] Seven, repeat step six twice, complete the preparation of the EBSD detection sample of the low conductivity metal powder with fine grains.

[0012] The beneficial effects of the present application are:

[0013] The EBSD sample prepared by the present application has good conductivity and high calibration rate, and solves the problem that the EBSD analysis of fine-grained low-conductivity metal powder cannot be performed due to the inability to prepare an EBSD sample. For example, the calibration rate of TC4 powder containing nano-TiB whiskers is close to 80%, while the powder embedded with resin cannot be used for EBSD testing. The sample preparation process of the present application is simple, short in time and low in cost, and can greatly improve the efficiency of preparing powder EBSD samples. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 EBSD test result graph of the EBSD detection sample prepared for the example. DETAILED DESCRIPTION

[0015] Specific embodiment one: the preparation method of the EBSD detection sample of the low conductivity metal powder with fine grains in the embodiment is specifically as follows:

[0016] One, a copper block is prepared by wire cutting;

[0017] Two, the surface to be tested of the copper block is polished smooth by sandpaper to obtain a polished copper block;

[0018] Three, the fine-grained low-conductivity metal powder to be tested is mixed with silver glue to obtain a mixed solution;

[0019] Four, the mixed solution is evenly applied to the surface to be tested of the polished copper block, and then placed in a ventilated place for air drying for 1-2 hours, and polished by sandpaper to expose the cross section of the powder to obtain a polished sample;

[0020] Five, SiO2 colloidal polishing liquid and H2O2 solution are mixed to configure an EBSD sample polishing liquid;

[0021] Six, the surface to be tested of the polished sample is polished on the polishing disc using a polishing cloth, and the EBSD sample polishing liquid is slowly added to the polishing cloth while polishing, and after the surface to be tested of the sample is polished without scratches, HF solution is used for etching treatment;

[0022] Seven, repeat step six twice to complete the preparation of the EBSD detection sample of the low conductivity metal powder with fine grains.

[0023] The innovation of the present embodiment lies in the sample preparation process, and the subsequent grinding and polishing process is similar to that of the block sample with slight changes in parameters, which is not the focus of the present application.

[0024] Specific implementation two: the difference between this embodiment and specific implementation one is that: the copper block in step one is a cube, a cylinder or other geometric body with two parallel faces; the length of the cube is less than 20 mm, the width is less than 20 mm, and the height is less than 20 mm; the diameter of the cylinder is less than 20 mm, and the height is less than 20 mm. The rest is the same as specific implementation one.

[0025] In this embodiment, the copper block has other shapes with two parallel upper and lower faces, such as a circular ring, etc.; the sample is too small to be easily polished, and too large to be suitable for scanning electron microscope analysis.

[0026] Specific implementation three: the difference between this embodiment and specific implementation one is that: in step two, the copper block is polished smooth with 2000# sandpaper. The rest is the same as specific implementation one.

[0027] Specific implementation four: the difference between this embodiment and specific implementation one is that: in step three, the volume ratio of the fine-grained low- conductivity metal powder to be tested to silver glue is 1:(2-10). The rest is the same as specific implementation one.

[0028] The silver glue content in this embodiment is too low, which can cause poor adhesion, and the powder is easy to fall off during polishing. If the amount of silver glue is too high, the mechanical strength will be low, the silver glue will be easy to crack and fall off during polishing, and the conductivity of the sample will be damaged, which will further reduce the calibration rate.

[0029] Specific implementation five: the difference between this embodiment and specific implementation one is that: in step four, the sandpaper polishing is performed in turn with 1000# sandpaper, 1500# sandpaper, 2000# sandpaper, 3000# sandpaper and 5000# sandpaper. The rest is the same as specific implementation one.

[0030] Specific implementation six: the difference between this embodiment and specific implementation one is that: in step five, the volume fraction of the H2O2 solution is 30%; the volume ratio of the SiO2 colloidal polishing liquid to the H2O2 solution is (9-10):1. The rest is the same as specific implementation one.

[0031] Specific implementation seven: the difference between this embodiment and specific implementation one is that: in step six, the polishing cloth is a porous neoprene polishing cloth. The rest is the same as specific implementation one.

[0032] Specific implementation eight: the difference between this embodiment and specific implementation seven is that: in step six, the polishing disc rotation speed is 80-100 r / min. The rest is the same as specific implementation seven.

[0033] Specific implementation nine: the difference between this embodiment and specific implementation one is that: in step six, the volume fraction of the HF solution is 1%. The rest is the same as specific implementation one.

[0034] Specific implementation ten: the difference between this embodiment and specific implementation nine is that the time of the etching treatment in step six is 4-5s. The others are the same as specific implementation nine.

[0035] The beneficial effects of the present application are verified by the following examples:

[0036] Example one: a preparation method of a low conductivity metal powder EBSD detection sample with fine grains is specifically performed according to the following steps:

[0037] I. A red copper block with a size of 5mm*5mm*3mm is prepared by wire cutting;

[0038] II. The surface to be tested of the red copper block is polished smooth by using 2000# sandpaper to obtain a polished copper block;

[0039] III. The nanocrystalline TC4 powder containing TiB whiskers is mixed with silver glue at a ratio of 1:5 to obtain a mixed solution;

[0040] IV. The mixed solution is evenly applied to the surface to be tested of the polished copper block, and then placed in a ventilated place for air drying for 1h, and then polished with 1000# sandpaper, 1500# sandpaper, 2000# sandpaper, 3000# sandpaper and 5000# sandpaper in turn until the powder section is exposed, to obtain a polished sample;

[0041] V. The SiO2 colloidal polishing liquid and the H2O2 solution are mixed to configure an EBSD sample polishing liquid; the volume fraction of the H2O2 solution is 30%; the volume ratio of the SiO2 colloidal polishing liquid to the H2O2 solution is 9:1;

[0042] VI. The surface to be tested of the polished sample is polished on the polishing disc using a porous neoprene polishing cloth, the polishing disc rotates at a speed of 90r / min, and the EBSD sample polishing liquid is slowly added to the polishing cloth while polishing, and after the surface to be tested of the sample is polished without scratches, an HF solution is used for etching treatment; the volume fraction of the HF solution is 1%, and the etching treatment time is 5s;

[0043] VII. Step VI is repeated twice to remove the scratches and stress layer on the surface of the powder, and the preparation of the EBSD detection sample of the low conductivity metal powder with fine grains is completed. Then the sample is adhered to the EBSD sample stage with silver glue for testing.

[0044] From Figure 1 It can be seen that the EBSD detection sample prepared by this embodiment is tested, the imaging in the figure is clear, and the imaging effect is good.

Claims

1. A method for preparing a low-conductivity metal powder sample with fine grains for EBSD detection, characterized in that... The preparation method for EBSD testing samples of low-conductivity metal powder with fine grains is carried out according to the following steps: I. Copper blocks are prepared using wire cutting; 2. The surface of the copper block to be tested is polished smooth with sandpaper to obtain the polished copper block; 3. Mix TC4 nanocrystal powder containing TiB whiskers with silver paste to obtain a mixture; the volume ratio of TC4 nanocrystal powder containing TiB whiskers to silver paste is 1:(2~10).

4. Apply the mixture evenly to the test surface of the polished copper block, then place it in a ventilated area to air dry for 1-2 hours. Polish it with sandpaper until the powder cross-section is exposed to obtain the polished sample. The sandpaper polishing is carried out in sequence with 1000# sandpaper, 1500# sandpaper, 2000# sandpaper, 3000# sandpaper, and 5000# sandpaper.

5. Prepare EBSD sample polishing solution by mixing SiO2 colloidal polishing slurry and H2O2 solution; the volume fraction of H2O2 solution is 30%; the volume ratio of SiO2 colloidal polishing slurry to H2O2 solution is (9~10):1; 6. Polish the test surface of the sample after grinding using a polishing cloth on a polishing pad. While polishing, slowly drop EBSD sample polishing liquid onto the polishing cloth. Polish until there are no scratches on the test surface of the sample, and then perform etching treatment with HF solution. The volume fraction of the HF solution is 1%. The etching treatment time is 4~5s. The polishing cloth is a porous neoprene polishing cloth.

7. Repeat step 6 twice to complete the preparation of EBSD test samples of low-conductivity metal powder with fine grains.

2. The method for preparing a low-conductivity metal powder sample with fine grains for EBSD detection according to claim 1, characterized in that... The copper block mentioned in step one is a cube, cylinder, or other geometric shape with two parallel faces; the cube has a length less than 20mm, a width less than 20mm, and a height less than 20mm; the cylinder has a diameter less than 20mm and a height less than 20mm.

3. The method for preparing a low-conductivity metal powder sample with fine grains for EBSD detection according to claim 1, characterized in that... In step two, the copper block is polished smooth using 2000# sandpaper.

4. The method for preparing a low-conductivity metal powder sample with fine grains for EBSD detection according to claim 1, characterized in that... The polishing disc rotation speed in step six is ​​80~100 r / min.

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