A Method for Electron Microscopy Sample Preparation and Analysis of Noble Metal Wear Debris

Abstract

This invention discloses a method for preparing and analyzing electron microscopy (EM) samples of precious metal wear debris, comprising: 1. grinding a metal block flat; 2. machining a cross-shaped groove on the upper surface; 3. pouring mounting powder into the cylinder of a metallographic thermal mounting machine and placing the metal block inside; 4. filling the cross-shaped groove of the metal block with a copper mesh, pouring the precious metal wear debris onto the copper mesh, and then pouring in mounting powder; 5. pressing, heating and maintaining the temperature to obtain a mounting block; 6. grinding and polishing; 7. metallographic etching to obtain an EEM sample of precious metal wear debris. This invention is simple to operate, low in cost, and highly applicable. It effectively enhances the current conductivity of wear debris, improves the clarity of microscopic images and the accuracy of component analysis in scanning electron microscopy, solves the problem of fixing and conductive connectivity of individual wear debris, and achieves the purpose of effectively analyzing the formation process and wear mechanism of wear debris.

Description

Technical Field

[0001] This invention belongs to the field of electron microscopy analysis technology for precious metal wear debris, specifically relating to a method for preparing and analyzing electron microscopy samples of precious metal wear debris. Background Technology

[0002] Precious metals and their alloys are commonly used as sliding electrical contact materials in precision instruments, ensuring high-precision continuous signal transmission between two relatively rotating components. During application and development, when the two contacting friction pairs move relative to each other, the interface experiences a certain degree of wear, generating fine wear debris. The degree of wear is affected by the material, contact load, applied current, relative speed, and operating environment. Interfacial friction and wear affect the safe operation of instruments and equipment. Effectively controlling interfacial friction and wear helps improve equipment reliability, extend service life, and save energy and raw materials. By analyzing the wear debris generated by wear, we can analyze its morphology and microstructure, determine the material evolution and wear mechanism of the wear process, and propose corresponding material and process designs.

[0003] The contact force of precious metal sliding electrical contact materials is relatively small, resulting in wear debris that is finely granular or elongated, with a size of 5-50 μm. Due to the small size of the particles, embedding, grinding, and polishing of the wear debris are difficult. Scanning electron microscopy (SEM) analysis of the morphology and microstructure of wear debris requires individual fine wear debris particles to have electrical conductivity. However, traditional metallographic embedding materials are resin or bakelite powder, which, due to their poor conductivity, cannot be imaged and analyzed under an SEM. Reinforced conductive embedding powders have poor density, making it difficult to fix the wear debris, which easily falls off during subsequent grinding, polishing, and metallographic etching. Furthermore, due to the small size of the wear debris particles, the conductivity of individual particles is poor. The formation process of wear debris involves adhesion, friction, and extrusion deformation, resulting in a smooth outer surface that masks the wear characteristics, such as the microstructure of the outer surface.

[0004] To analyze the wear debris generated by sliding friction and wear of precious metal materials, scanning electron microscopy is used to analyze the internal and external morphology and microstructure of the wear debris. This invention patent solves the problem of embedding and fixing individual fine wear debris and ensuring its electrical conductivity. It proposes a method for preparing and analyzing wear debris samples for electron microscopy, which can effectively analyze the formation process and wear mechanism of wear debris. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a method for preparing and analyzing electron microscopy samples of precious metal wear debris, addressing the shortcomings of the prior art. This method is simple to operate, low in cost, and highly applicable. It effectively enhances the current conductivity of wear debris, improves the clarity of microscopic images and the accuracy of component analysis in scanning electron microscopy, and solves the problems of embedding and fixing individual fine wear debris and ensuring conductive connectivity. This achieves the goal of effectively analyzing the formation process and wear mechanism of wear debris.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing electron microscopy samples of precious metal wear debris, characterized by comprising the following steps:

[0007] Step 1: Use an acid-resistant metal block as a conductive carrier, and polish the upper and lower surfaces of the metal block with sandpaper until smooth.

[0008] Step 2: Machin a cross-shaped groove on the upper surface of the metal block after grinding in Step 1, and use a blade to score the bottom of the cross-shaped groove into a rough surface with fine grooves.

[0009] Step 3: Pour the inlay powder onto the lower pressure block of the metallographic hot inlay machine cylinder and compact it with the upper pressure block; then place the metal block processed in Step 2 with the cross-shaped groove facing upward into the inlay powder and press the metal block into the inlay powder with the pressure block;

[0010] Step 4: Fill the cross-shaped groove of the metal block with copper mesh, then pour precious metal wear debris onto the copper mesh. The accumulation height of the precious metal wear debris shall not exceed the plane of the metal block. Then pour inlay powder into the cross-shaped groove of the metal block.

[0011] Step 5: Press the upper pressure block onto the metal block into which the inlay powder was poured in step 4, press it tightly, then heat it to 130℃~140℃, press it tightly again, and then keep it at 130℃~140℃ for 8min~10min. After the holding time is over, cool it to room temperature to obtain the inlay block.

[0012] Step Six: Grind the bottom and top of the sample block described in Step Five with 400-grit sandpaper until a metal block is exposed; then grind the top of the sample block with 1000-1200-grit sandpaper until a bright layer of precious metal wear debris is exposed; then grind the top of the sample block with 2000-3000-grit sandpaper until there are no scratches; water cooling is used during all the grinding processes.

[0013] Step 7: Use alloy metallographic etching solution to perform metallographic etching on the surface of the precious metal wear debris layer after polishing in Step 6, rinse with water, dehydrate with alcohol, and blow dry to obtain an electron microscopy sample of precious metal wear debris.

[0014] The method for preparing electron microscopy samples of precious metal wear debris described above is characterized in that the metal block in step one is made of titanium, tantalum or niobium and has a square cross-section; the cross-shaped groove in step two has a width of 1.2 mm to 1.5 mm and a depth of 1.2 mm to 2.0 mm.

[0015] The method for preparing electron microscopy samples of precious metal wear debris described above is characterized in that the inlay powder in step three is bakelite powder, with a weight of 2g to 5g; and the pressure of the upper pressure block in step three is 20MPa to 30MPa.

[0016] The method for preparing electron microscopy samples of precious metal wear debris described above is characterized in that the copper mesh in step four has a mesh size of 400-500; the number of precious metal wear debris particles is 20-100; and the weight of the inlaid powder is 3g-7g.

[0017] The method for preparing electron microscopy samples of precious metal wear debris described above is characterized in that the pressure of the upper pressure block in step five is 25 MPa to 30 MPa.

[0018] The method for preparing electron microscopic samples of precious metal wear debris described above is characterized in that the metallographic etching process in step seven includes wiping the sample 5 to 10 times with cotton soaked in alloy metallographic etching solution.

[0019] Furthermore, the present invention also provides an electron microscopy analysis method for precious metal wear debris, characterized in that it includes internal structure analysis and external structure analysis of precious metal wear debris.

[0020] The internal structure analysis of the precious metal wear debris includes: attaching conductive adhesive to the bottom of the electron microscope sample of the precious metal wear debris prepared by the method of claim 1, placing it on the sample stage, and then placing it together in the electron microscope vacuum chamber for vacuuming. After vacuuming, using a cross-shaped groove as a positioning tool, the location of the debris is determined, and microscopic images of the debris morphology are taken at 100 to 1000x magnification, and microscopic images of the debris microstructure are taken at 2000 to 30000x magnification to analyze the distribution of alloying elements at the characteristic locations of the debris.

[0021] The external structure analysis of the precious metal wear debris includes the following steps:

[0022] Step 1: Pour precious metal abrasion shavings into a glass bottle, then add metallographic etching solution, shake for 15s to 30s, then add water, ultrasonically vibrate for 30s to 50s, let stand for 30s to 60s, and then remove the solution along the glass bottle wall.

[0023] Step 2: Add water to the glass bottle after the solution was removed in Step 1, vibrate ultrasonically for 20-30 seconds, let stand for 30-60 seconds, and then blot the solution along the glass bottle wall.

[0024] Step 3: Repeat the method in Step 2 2-3 times and let it air dry naturally; then use conductive adhesive to pick up the precious metal wear debris from the bottom of the bottle and analyze the external structure, morphology and composition distribution of the precious metal wear debris in a scanning electron microscope.

[0025] The above-mentioned method for electron microscopy analysis of precious metal wear debris is characterized in that the vacuuming voltage is 10kV to 15kV, and the distance between the electron microscope sample plane and the scanning electron gun and lens is 3mm to 5mm.

[0026] The above-mentioned method for electron microscopy analysis of precious metal wear debris is characterized in that the volume of water in step one is 2 to 4 times the volume of the metallographic etching solution.

[0027] The above-mentioned method for electron microscopy analysis of precious metal wear debris is characterized in that the volume of water in step two is 2 to 4 times the volume of metallographic etching solution in step one.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] 1. This invention uses an acid-resistant metal block as a conductive carrier to prepare electron microscopy samples. The metal block primarily provides current conduction for the precious metal wear debris, while simultaneously ensuring that the wear debris retains its internal structure under the action of the metallographic etching solution. By machining cross-shaped grooves on the metal block, powder can be firmly embedded, allowing the wear debris to maintain stable contact with the metal block or copper mesh, ensuring that the wear debris will not fall off during sandpaper grinding and polishing. Filling with copper mesh enhances the current conduction of the wear debris.

[0030] 2. The cross-shaped groove of the present invention preferably has a width of 1.2mm to 1.5mm and a depth of 1.2mm to 2.0mm. This size is beneficial to the stable embedding of powder and wear debris, and further improves the current conductivity of wear debris.

[0031] 3. The electron microscopy sample preparation method of the present invention is simple to operate, low in cost, and highly applicable. It can effectively enhance the current conductivity of wear debris, improve the clarity of microstructure images and the accuracy of component analysis in scanning electron microscopy, and solve the problem of embedding and fixing individual fine wear debris and ensuring its electrical conductivity, thereby achieving the purpose of effectively analyzing the formation process and wear mechanism of wear debris.

[0032] 4. The external structure analysis method for precious metal wear debris of the present invention is simple and easy to operate. Metallographic etching solution is used to remove the extrusion and friction deformation layer on the surface of the wear debris, revealing the external structure and morphology of the wear debris; ultrasonic vibration is used to remove the corrosion products generated on the surface of the wear debris; conductive adhesive is used to stick the wear debris, fix the wear debris, and play a conductive role.

[0033] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0034] Figure 1 This is a top view of the cross-shaped groove of the present invention.

[0035] Figure 2 for Figure 1 AA sectional view.

[0036] Figure 3 This is a schematic diagram of the structure of the metal block after being filled with copper mesh according to the present invention.

[0037] Figure 4 This is a schematic diagram of the structure of the metal block after adding precious metal wear debris according to the present invention.

[0038] Figure 5 This is a schematic diagram of the electron microscope sample preparation of precious metal wear debris using a metallographic hot mounting machine according to the present invention.

[0039] Figure 6 This is a scanning electron microscope image of the internal structure of gold alloy wear debris analyzed using the direct mounting method.

[0040] Figure 7 This is a scanning electron microscope image of the internal structure of gold alloy wear debris analyzed in Example 5 of the present invention.

[0041] Figure 8 This is a diagram showing the original external structure of wear debris from a gold alloy.

[0042] Figure 9 This is an external structural diagram of the gold alloy wear debris analyzed in Example 5 of the present invention.

[0043] Figure 10 This is a scanning electron microscope image of the internal structure of gold alloy wear debris analyzed in Example 6 of the present invention.

[0044] Figure 11 External structure diagram of gold alloy wear debris analyzed in Example 6 of this invention.

[0045] Figure 12 This is a scanning electron microscope image of the internal structure of gold alloy wear debris analyzed in Example 7 of the present invention.

[0046] Figure 13 This is an external structural diagram of the gold alloy wear debris analyzed in Example 7 of the present invention.

[0047] Explanation of reference numerals in the attached figures:

[0048] 1—Metal block; 2—Cross-shaped groove; 3—Beveled angle;

[0049] 4—Copper mesh; 5—Wear debris from precious metal wear. Detailed Implementation

[0050] Example 1

[0051] Gold alloy wear debris was collected. The debris was in the form of fine particles with a size of 5μm to 50μm. The debris was packaged in capacitor paper with a size of 40mm to 60mm, which has the characteristics of non-porous adhesion and electrostatic adsorption.

[0052] The electron microscopy sample preparation method for precious metal wear debris in this embodiment includes the following steps:

[0053] Step 1: Use a square-section metal block that is resistant to acid corrosion as a conductive carrier. Sand the upper and lower surfaces of the metal block smooth. The metal block is made of titanium and has a length of 4mm, a width of 4mm, and a height of 7mm.

[0054] Step Two, as follows Figures 1-4 As shown, a cross-shaped groove 2 is machined on the upper surface of the metal block 1 after grinding in step one, and the bottom of the cross-shaped groove 2 is scratched with a blade to form a rough surface with fine grooves; the width of the cross-shaped groove is 1.5mm, the depth is 1.5mm, and the edge of the groove is beveled 3.

[0055] Step 3, as follows Figure 5 As shown, the inlay powder is poured onto the lower pressure block of the metallographic thermal inlay machine cylinder, which has a diameter of 25mm. The inlay powder is bakelite powder, and its weight is 2.0g. It is then compacted with the upper pressure block at a pressure of 20MPa. Next, the metal block processed in step two is placed into the inlay powder with the cross-shaped groove facing upwards, and the upper pressure block is used to press the metal block into the inlay powder.

[0056] Step 4: Fill the cross-shaped groove 2 of the metal block with a 400-500 mesh copper mesh 4. The copper mesh is 2.0 mm wide and 4 mm long. Then pour precious metal abrasive shavings 5 ​​onto the copper mesh 4. The accumulation height of the precious metal abrasive shavings should not exceed the plane of the metal block. Then pour inlay powder (bakelite powder) into the cross-shaped groove of the metal block. The number of precious metal abrasive shavings particles is 20-100, and the weight of the inlay powder poured in is 3.8 g.

[0057] Step 5: Press the metal block into which the embedding powder was poured in step 4 onto the upper pressure block. The pressure is 30MPa. After pressing, heat it to 130℃, press it again, and then keep it at 130℃ for 10 minutes. After the holding time is over, cool it to room temperature to obtain the mounting block.

[0058] Step Six: Grind the bottom and top of the mounting block described in Step Five with 400-grit sandpaper, cool with water, and rotate at 90° to ensure it is smooth. Grind to a depth of 1mm to expose the cross-shaped metal block. Then, grind the top of the mounting block with 1000-grit sandpaper, cool with water, until a bright layer of precious metal wear debris is exposed. Finally, grind the top of the mounting block with 2000-grit sandpaper, polish with a silk cloth, and observe under a metallographic microscope to find no scratches.

[0059] Step 7: Add 0.5g of chromium trioxide to 20mL of hydrochloric acid. After it is completely dissolved, dilute it with 15mL of water to obtain an alloy metallographic etching solution of chromium trioxide and hydrochloric acid. Soak cotton with the alloy metallographic etching solution and wipe the surface of the polished precious metal wear debris layer 5 to 10 times to perform metallographic etching. Rinse with water, dehydrate with alcohol, and blow dry to obtain an electron microscopy sample of precious metal wear debris.

[0060] Example 2

[0061] Gold alloy wear debris was collected. The debris was in the form of fine particles with a size of 5μm to 50μm. The debris was packaged in capacitor paper with a size of 40mm to 60mm, which has the characteristics of non-porous adhesion and electrostatic adsorption.

[0062] The electron microscopy sample preparation method for precious metal wear debris in this embodiment includes the following steps:

[0063] Step 1: Use a square-section metal block that is resistant to acid corrosion as a conductive carrier. Polish the upper and lower surfaces of the metal block with sandpaper until smooth. The metal block is made of tantalum and has a length of 6mm, a width of 6mm, and a height of 10mm.

[0064] Step Two, as follows Figures 1-4 As shown, a cross-shaped groove 2 is machined on the upper surface of the metal block 1 after grinding in step one, and the bottom of the cross-shaped groove 2 is scratched with a blade to form a rough surface with fine grooves; the width of the cross-shaped groove is 1.2mm, the depth is 1.2mm, and the edge of the groove is beveled 3.

[0065] Step 3, as follows Figure 5 As shown, the inlay powder is poured onto the lower pressure block of the metallographic thermal inlay machine cylinder, which has a diameter of 25mm. The inlay powder is bakelite powder, and its weight is 3.0g. It is then compacted with the upper pressure block at a pressure of 20MPa. Next, the metal block processed in step two is placed into the inlay powder with the cross-shaped groove facing upwards, and the upper pressure block is used to press the metal block into the inlay powder.

[0066] Step 4: Fill the cross-shaped groove 2 of the metal block with a 400-500 mesh copper mesh 4. The copper mesh is 2.0 mm wide and 4 mm long. Then pour precious metal abrasive shavings 5 ​​onto the copper mesh 4. The accumulation height of the precious metal abrasive shavings should not exceed the plane of the metal block. Then pour inlay powder (bakelite powder) into the cross-shaped groove of the metal block. The number of precious metal abrasive shavings particles is 20-100, and the weight of the inlay powder poured in is 3.8 g.

[0067] Step 5: Press the metal block into which the embedding powder was poured in step 4 onto the upper pressure block. The pressure is 28MPa. After pressing, heat it to 140℃, press it again, and then keep it at 140℃ for 8 minutes. After the holding time is over, cool it to room temperature to obtain the mounting block.

[0068] Step Six: Grind the bottom and top of the mounting block described in Step Five with 400-grit sandpaper, cool with water, and rotate at 90° to ensure it is smooth. Grind to a depth of 1mm to expose the cross-shaped metal block. Then, grind the top of the mounting block with 1200-grit sandpaper, cool with water, until a bright layer of precious metal wear debris is exposed. Finally, grind the top of the mounting block with 3000-grit sandpaper, polish with a silk cloth, and observe under a metallographic microscope to find no scratches.

[0069] Step 7: Add 0.5g of chromium trioxide to 20mL of hydrochloric acid. After it is completely dissolved, dilute it with 15mL of water to obtain an alloy metallographic etching solution of chromium trioxide and hydrochloric acid. Soak cotton with the alloy metallographic etching solution and wipe the surface of the polished precious metal wear debris layer 5 to 10 times to perform metallographic etching. Rinse with water, dehydrate with alcohol, and blow dry to obtain an electron microscopy sample of precious metal wear debris.

[0070] Example 3

[0071] Gold alloy wear debris was collected. The debris was in the form of fine particles with a size of 5μm to 50μm. The debris was packaged in capacitor paper with a size of 40mm to 60mm, which has the characteristics of non-porous adhesion and electrostatic adsorption.

[0072] The electron microscopy sample preparation method for precious metal wear debris in this embodiment includes the following steps:

[0073] Step 1: Use a square-section metal block that is resistant to acid corrosion as a conductive carrier. Sand the upper and lower surfaces of the metal block smooth. The metal block is made of niobium and has a length of 8mm, a width of 8mm, and a height of 15mm.

[0074] Step Two, as follows Figures 1-4 As shown, a cross-shaped groove 2 is machined on the upper surface of the metal block 1 after grinding in step one, and the bottom of the cross-shaped groove 2 is scratched with a blade to form a rough surface with fine grooves; the width of the cross-shaped groove is 1.5mm, the depth is 2.0mm, and the edge of the groove is beveled 3.

[0075] Step 3, as follows Figure 5 As shown, the inlay powder is poured onto the lower pressure block of the metallographic thermal inlay machine cylinder, which has a diameter of 25mm. The inlay powder is bakelite powder, and its weight is 5.0g. It is then compacted with the upper pressure block at a pressure of 30MPa. Next, the metal block processed in step two is placed into the inlay powder with the cross-shaped groove facing upwards, and the upper pressure block is used to press the metal block into the inlay powder.

[0076] Step 4: Fill the cross-shaped groove 2 of the metal block with a 400-500 mesh copper mesh 4. The copper mesh is 2.0 mm wide and 8 mm long. Then pour precious metal abrasive shavings 5 ​​onto the copper mesh 4. The accumulation height of the precious metal abrasive shavings should not exceed the plane of the metal block. Then pour inlay powder (bakelite powder) into the cross-shaped groove of the metal block. The number of precious metal abrasive shavings particles is 20-100, and the weight of the inlay powder poured in is 7.0 g.

[0077] Step 5: Press the metal block into which the embedding powder was poured in step 4 onto the upper pressure block. The pressure is 30MPa. After pressing, heat it to 135℃, press it again, and then keep it at 135℃ for 9 minutes. After the holding time is over, cool it to room temperature to obtain the mounting block.

[0078] Step Six: Grind the bottom and top of the mounting block described in Step Five with 400-grit sandpaper, cool with water, and alternate at 90° to ensure it is smooth. Grind to a depth of 1mm to expose the cross-shaped metal block. Then, grind the top of the mounting block with 1000-grit sandpaper, cool with water, until a bright layer of precious metal wear debris is exposed. Finally, grind the top of the mounting block with 2500-grit sandpaper, polish with a silk cloth, and observe under a metallographic microscope to find no scratches.

[0079] Step 7: Add 0.5g of chromium trioxide to 20mL of hydrochloric acid. After it is completely dissolved, dilute it with 15mL of water to obtain an alloy metallographic etching solution of chromium trioxide and hydrochloric acid. Soak cotton with the alloy metallographic etching solution and wipe the surface of the polished precious metal wear debris layer 5 to 10 times to perform metallographic etching. Rinse with water, dehydrate with alcohol, and blow dry to obtain an electron microscopy sample of precious metal wear debris.

[0080] Example 4

[0081] Silver alloy wear debris was collected. The debris was in the form of fine particles with a size of 5μm to 50μm. The debris was packaged in capacitor paper with a size of 40mm to 60mm, which has the characteristics of non-porous adhesion and electrostatic adsorption.

[0082] The electron microscopy sample preparation method for precious metal wear debris in this embodiment includes the following steps:

[0083] Step 1: Use a square-section metal block that is resistant to acid corrosion as a conductive carrier. Sand the upper and lower surfaces of the metal block smooth. The metal block is made of titanium and has a length of 6mm, a width of 6mm, and a height of 10mm.

[0084] Step Two, as follows Figures 1-4 As shown, a cross-shaped groove 2 is machined on the upper surface of the metal block 1 after grinding in step one, and the bottom of the cross-shaped groove 2 is scratched with a blade to form a rough surface with fine grooves; the width of the cross-shaped groove is 1.4 mm, the depth is 1.4 mm, and the edge of the groove is beveled 3.

[0085] Step 3, as follows Figure 5 As shown, the inlay powder is poured onto the lower pressure block of the metallographic thermal inlay machine cylinder, which has a diameter of 25mm. The inlay powder is bakelite powder, and its weight is 3.0g. It is then compacted with the upper pressure block at a pressure of 25MPa. Next, the metal block processed in step two is placed into the inlay powder with the cross-shaped groove facing upwards, and the upper pressure block is used to press the metal block into the inlay powder.

[0086] Step 4: Fill the cross-shaped groove 2 of the metal block with a 400-500 mesh copper mesh 4. The copper mesh is 2.0 mm wide and 6 mm long. Then pour precious metal abrasion micro-shavings 5 ​​onto the copper mesh 4. The accumulation height of the precious metal abrasion micro-shavings should not exceed the plane of the metal block. Then pour inlay powder (bakelite powder) into the cross-shaped groove of the metal block. The number of precious metal abrasion micro-shavings is 20-100 particles, and the weight of the inlay powder poured in is 5.0 g.

[0087] Step 5: Press the metal block into which the embedding powder was poured in step 4 onto the upper pressure block. The pressure is 25MPa. After pressing, heat it to 130℃, press it again, and then keep it at 130℃ for 10 minutes. After the holding time is over, cool it to room temperature to obtain the mounting block.

[0088] Step Six: Grind the bottom and top of the mounting block described in Step Five with 400-grit sandpaper, cool with water, and rotate at 90° to ensure it is smooth. Grind to a depth of 1mm to expose the cross-shaped metal block. Then, grind the top of the mounting block with 1000-grit sandpaper, cool with water, until a bright layer of precious metal wear debris is exposed. Finally, grind the top of the mounting block with 2000-grit sandpaper, polish with a silk cloth, and observe under a metallographic microscope to find no scratches.

[0089] Step 7: Mix ammonia and hydrogen peroxide solution in a 1:1 volume ratio to obtain an alloy metallographic etching solution. Soak cotton in the alloy metallographic etching solution and wipe the surface of the polished precious metal wear debris layer 2 to 5 times to perform metallographic etching. Rinse with water, dehydrate with alcohol, and blow dry to obtain an electron microscopy sample of precious metal wear debris.

[0090] Example 5

[0091] Electron microscopy analysis was performed on the gold alloy wear debris collected in Example 1 of the present invention, including internal structure analysis and external structure analysis of the precious metal wear debris.

[0092] The internal structure analysis of the precious metal wear debris included: attaching conductive adhesive to the bottom of the electron microscope sample of the precious metal wear debris prepared in Example 1, placing it on the sample stage, and then placing it together in the electron microscope vacuum chamber for evacuation. After evacuation, using a cross-shaped groove as a positioning tool, the location of the debris was determined. The morphology of the debris was photographed at 100-1000x magnification, and the microstructure of the debris was photographed at 2000-30000x magnification to analyze the distribution of alloying elements at the characteristic locations of the debris. The evacuation voltage was 10kV, and the distance between the electron microscope sample plane and the scanning electron gun and lens was 3mm.

[0093] The results are as follows Figure 7 As shown in the figure, the wear debris has a clear outline and distinct cross-sectional morphology, revealing cracks and streamlines in its microstructure. This is compared to the scanning electron microscope image of the internal microstructure of gold alloy wear debris analyzed using the direct mounting method. Figure 6 Compared to other methods, wear debris exhibits clearer microstructure characteristics, without ghosting or white light, resulting in more accurate component analysis.

[0094] The external structure analysis of the precious metal wear debris includes:

[0095] Step 1: Pour a small amount of precious metal wear debris into a glass bottle with a diameter of 10 mm and a height of 50 mm; then add 1 mL of metallographic etching solution (the same metallographic etching solution used in Example 1), shake for 15 seconds, then add 2 mL of water, ultrasonically vibrate for 30 seconds, let stand for 30 seconds, and then use a pipette to remove the solution along the glass bottle wall from a distance of 3 to 8 mm from the bottom of the bottle.

[0096] Step 2: Add 2mL of water to the glass bottle after the solution was removed in Step 1, sonicate for 20s, let stand for 30s, and use a pipette to remove the solution along the glass bottle wall from a distance of 3-8mm from the bottom of the bottle.

[0097] Step 3: Repeat the method in Step 2 twice and let it air dry. Then, use conductive adhesive with a length of 3 mm and a width of 3 mm to stick out the precious metal wear debris from the bottom of the bottle. Analyze the external structure, morphology and composition distribution of the precious metal wear debris in a scanning electron microscope.

[0098] See results Figure 9 As can be seen from the figure, the external structure of the wear debris is a layered streamlined structure, with blocky metal accumulations at the edges. (Compared to the original external structure of the gold alloy wear debris...) Figure 8Compared to the previous method, the external structure and organization characteristics of wear debris are obvious. After removing the extrusion and friction deformation layer on the surface of wear debris, the external structure and morphology of wear debris are revealed.

[0099] Example 6

[0100] Electron microscopy analysis was performed on the gold alloy wear debris collected in Example 2 of the present invention, including the internal structure analysis and the external structure analysis of the precious metal wear debris.

[0101] The internal structure analysis of the precious metal wear debris included: attaching conductive adhesive to the bottom of the electron microscope sample of the precious metal wear debris prepared in Example 2, placing it on the sample stage, and then placing it together in the electron microscope vacuum chamber for evacuation. After evacuation, using a cross-shaped groove as a positioning tool, the location of the debris was determined. The morphology of the debris was photographed at 100-1000x magnification, and the microstructure of the debris was photographed at 2000-30000x magnification to analyze the distribution of alloying elements at the characteristic locations of the debris. The evacuation voltage was 15kV, and the distance between the electron microscope sample plane and the scanning electron gun and lens was 5mm.

[0102] The results are as follows Figure 10 As shown in the figure, the wear debris has a clear outline and distinct cross-sectional morphology, without any ghosting or white highlights. This is compared to the scanning electron microscope image of the internal structure of gold alloy wear debris analyzed by the direct mounting method. Figure 6 Compared to other materials, wear debris exhibits more distinct microstructural characteristics.

[0103] The external structure analysis of the precious metal wear debris includes:

[0104] Step 1: Pour a small amount of precious metal wear debris into a glass bottle with a diameter of 15 mm and a height of 80 mm; then add 2 mL of metallographic etching solution (the same metallographic etching solution used in Example 2), shake for 30 seconds, then add 6 mL of water, ultrasonically vibrate for 50 seconds, let stand for 60 seconds, and then use a pipette to remove the solution along the glass bottle wall from a distance of 3 to 8 mm from the bottom of the bottle.

[0105] Step 2: Add 6 mL of water to the glass bottle after the solution was removed in Step 1, sonicate for 30 seconds, let stand for 60 seconds, and use a pipette to remove the solution along the glass bottle wall from a distance of 3-8 mm from the bottom of the bottle.

[0106] Step 3: Repeat the method in Step 2 three times and let it air dry. Then, use conductive adhesive with a length of 5 mm and a width of 5 mm to stick out the precious metal wear debris from the bottom of the bottle. Analyze the external structure, morphology and composition distribution of the precious metal wear debris in a scanning electron microscope.

[0107] See results Figure 11 As can be seen from the figure, the external structure of the wear debris is lamellar. (Compared to the original external structure of the gold alloy wear debris...) Figure 8 Compared to the previous method, the external structure and organization characteristics of wear debris are more obvious.

[0108] Example 7

[0109] Electron microscopy analysis was performed on the gold alloy wear debris collected in Example 3 of the present invention, including the internal structure analysis and the external structure analysis of the precious metal wear debris.

[0110] The internal structure analysis of the precious metal wear debris included: attaching conductive adhesive to the bottom of the electron microscope sample of the precious metal wear debris prepared in Example 4, placing it on the sample stage, and then placing it together in the electron microscope vacuum chamber for evacuation. After evacuation, using a cross-shaped groove as a positioning tool, the location of the debris was determined. The morphology of the debris was photographed at 100-1000x magnification, and the microstructure of the debris was photographed at 2000-30000x magnification to analyze the distribution of alloying elements at the characteristic locations of the debris. The evacuation voltage was 12kV, and the distance between the electron microscope sample plane and the scanning electron gun and lens was 4mm.

[0111] The results are as follows Figure 12 As shown in the figure, the wear debris has a clear outline and distinct cross-sectional morphology. This is compared to the scanning electron microscope image of the internal structure of gold alloy wear debris analyzed by the direct mounting method. Figure 6 In contrast, the wear debris exhibits distinct microstructural characteristics and lacks ghosting or white light.

[0112] The external structure analysis of the precious metal wear debris includes:

[0113] Step 1: Pour a small amount of precious metal wear debris into a glass bottle with a diameter of 12 mm and a height of 60 mm; then add 1 mL of metallographic etching solution (the same metallographic etching solution used in Example 4), shake for 20 seconds, then add 4 mL of water, ultrasonically vibrate for 40 seconds, let stand for 50 seconds, and then use a pipette to remove the solution along the glass bottle wall from a distance of 3 to 8 mm from the bottom of the bottle.

[0114] Step 2: Add 4 mL of water to the glass bottle after the solution was removed in Step 1, sonicate for 25 seconds, let stand for 50 seconds, and use a pipette to remove the solution along the glass bottle wall from a distance of 3-8 mm from the bottom of the bottle.

[0115] Step 3: Repeat the method in Step 2 twice and let it air dry. Then, use conductive adhesive with a length of 4 mm and a width of 4 mm to stick out the precious metal wear debris from the bottom of the bottle. Analyze the external structure, morphology and composition distribution of the precious metal wear debris in a scanning electron microscope.

[0116] See results Figure 13 As can be seen from the figure, the external structure of the wear debris is lamellar. (Compared to the original external structure of the gold alloy wear debris...) Figure 8Compared to the previous method, the external structure and organization characteristics of wear debris are more obvious.

[0117] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing electron microscopy samples of precious metal wear debris, characterized in that, Includes the following steps: Step 1: Use an acid-resistant metal block as a conductive carrier, and polish the upper and lower surfaces of the metal block with sandpaper until smooth. Step 2: Machin a cross-shaped groove on the upper surface of the metal block after grinding in Step 1, and use a blade to score the bottom of the cross-shaped groove into a rough surface with fine grooves. Step 3: Pour the inlay powder onto the lower pressure block of the metallographic hot inlay machine cylinder and compact it with the upper pressure block; then place the metal block processed in Step 2 with the cross-shaped groove facing upward into the inlay powder and press the metal block into the inlay powder with the pressure block; Step 4: Fill the cross-shaped groove of the metal block with copper mesh, then pour precious metal wear debris onto the copper mesh. The accumulation height of the precious metal wear debris shall not exceed the plane of the metal block. Then pour inlay powder into the cross-shaped groove of the metal block. Step 5: Press the upper pressure block onto the metal block into which the inlay powder was poured in step 4, press it tightly, then heat it to 130℃~140℃, press it tightly again, and then keep it at 130℃~140℃ for 8min~10min. After the holding time is over, cool it to room temperature to obtain the inlay block. Step Six: Grind the bottom and top of the sample block described in Step Five with 400-grit sandpaper until a metal block is exposed; then grind the top of the sample block with 1000-1200-grit sandpaper until a bright layer of precious metal wear debris is exposed; then grind the top of the sample block with 2000-3000-grit sandpaper until there are no scratches; water cooling is used during all the grinding processes. Step 7: Use alloy metallographic etching solution to perform metallographic etching on the surface of the precious metal wear debris layer after polishing in Step 6, rinse with water, dehydrate with alcohol, and blow dry to obtain an electron microscopy sample of precious metal wear debris.

2. The method for preparing electron microscopy samples of precious metal wear debris according to claim 1, characterized in that, The metal block mentioned in step one is made of titanium, tantalum, or niobium, and has a square cross-section; the cross-shaped groove mentioned in step two has a width of 1.2mm to 1.5mm and a depth of 1.2mm to 2.0mm.

3. The method for preparing electron microscopy samples of precious metal wear debris according to claim 1, characterized in that, The inlay powder mentioned in step three is bakelite powder, weighing 2g to 5g; the pressure of the upper pressing block mentioned in step three is 20MPa to 30MPa.

4. The method for preparing electron microscopy samples of precious metal wear debris according to claim 1, characterized in that, The copper mesh in step four has a mesh size of 400-500; the number of precious metal abrasion micro-shavings is 20-100; and the weight of the inlay powder is 3g-7g.

5. The method for preparing electron microscopy samples of precious metal wear debris according to claim 1, characterized in that, The pressure of the upper pressure block in step five is 25MPa to 30MPa.

6. The method for preparing electron microscopy samples of precious metal wear debris according to claim 1, characterized in that, The specific process of metallographic etching described in step seven includes wiping the surface 5 to 10 times with cotton soaked in alloy metallographic etching solution.

7. An electron microscopy analysis method for precious metal wear debris, characterized in that, This includes the internal structure analysis and external structure analysis of precious metal wear debris; The internal structure analysis of the precious metal wear debris includes: attaching conductive adhesive to the bottom of the electron microscope sample of the precious metal wear debris prepared by the method of claim 1, placing it on the sample stage, and then placing it together in the electron microscope vacuum chamber for vacuuming. After vacuuming, using a cross-shaped groove as a positioning tool, the location of the debris is determined, and microscopic images of the debris morphology are taken at 100 to 1000x magnification, and microscopic images of the debris microstructure are taken at 2000 to 30000x magnification to analyze the distribution of alloying elements at the characteristic locations of the debris. The external structure analysis of the precious metal wear debris includes the following steps: Step 1: Pour precious metal abrasion shavings into a glass bottle, then add metallographic etching solution, shake for 15s to 30s, then add water, ultrasonically vibrate for 30s to 50s, let stand for 30s to 60s, and then remove the solution along the glass bottle wall. Step 2: Add water to the glass bottle after the solution was removed in Step 1, vibrate ultrasonically for 20-30 seconds, let stand for 30-60 seconds, and then blot the solution along the glass bottle wall. Step 3: Repeat the method in Step 2 2-3 times and let it air dry naturally; then use conductive adhesive to pick up the precious metal wear debris from the bottom of the bottle and analyze the external structure, morphology and composition distribution of the precious metal wear debris in a scanning electron microscope.

8. The electron microscopy analysis method for precious metal wear debris according to claim 7, characterized in that, The vacuuming voltage is 10kV to 15kV, and the distance between the electron microscope sample plane and the scanning electron gun and lens is 3mm to 5mm.

9. The electron microscopy analysis method for precious metal wear debris according to claim 7, characterized in that, In step one, the volume of water is 2 to 4 times the volume of the metallographic etching solution.

10. The electron microscopy analysis method for precious metal wear debris according to claim 7, characterized in that, In step two, the volume of water is 2 to 4 times the volume of the metallographic etching solution in step one.

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