An etchant and rapid inspection method for copper and copper alloy microstructures

Abstract

The invention discloses an etchant and a rapid inspection method for the microstructure of copper and copper alloys. Relevant steps are determined according to the specific conditions of a sample to be tested, thereby achieving rapid inspection and avoiding waste of relevant resources. A water mill and immersion in the etchant are used to eliminate deeper scratches and stains, thereby freeing manual labor from simple and repetitive metallographic polishing work. In addition, the etchant of the invention has a moderate corrosion rate, is easy for operators to use, and reduces the occurrence of insufficient or excessive corrosion. The etchant of the invention has a decontamination ability, thereby avoiding interference of dust or impurities on a flannel cloth during polishing with subsequent etching. The etchant has little harm to the environment and poses no health risk to operators. The etchant can be used in poorly ventilated places and has a wide range of uses.

Description

Technical Field

[0001] The present invention relates to the technical field of rapid microstructure inspection, in particular to an etchant for copper and copper alloy microstructures and a rapid inspection method. Background Art

[0002] Metallographic analysis is a method that uses a metallographic microscope to study the size, morphology, distribution, quantity, and properties of the microstructure of metals and alloys. It holds a crucial position in the field of metal materials research. The method of using a metallographic microscope to magnify a specially prepared specimen by 50x to 1500x to study the internal structure and defects of metals and alloys is called metallographic microanalysis. It is the most basic experimental technique for studying the microstructure of metal materials. Microscopic analysis can study the relationship between the structure and chemical composition of metals and alloys; determine the microstructure of various alloy materials after different processing and heat treatments; and determine the quality of metal materials, such as the quantity and distribution of various non-metallic inclusions such as oxides and sulfides in the structure, as well as the size of the metal grains.

[0003] The preparation of metallographic analysis specimens for copper and copper alloy products generally involves steps such as grinding, polishing, and etching. Existing etchants commonly used for copper and copper alloys have some rapid corrosion rates during the etching process, requiring operators to precisely control the etching time, otherwise localized excessive corrosion can occur, placing high demands on the operator. Some etchants, while effective, contain potassium dichromate, a heavy metal ion that seriously pollutes the environment. Others contain ammonia, a volatile substance that cannot be used in poorly ventilated areas. The use of these etchants often results in a pungent, odor that is difficult to dissipate, posing a serious health risk to operators. Furthermore, existing etchants lack the ability to remove dust and other impurities carried by polishing cloths, potentially resulting in uneven corrosion. Existing microstructural inspection methods mechanically apply a single set of testing methods to different products, resulting in many unnecessary inspection steps and a waste of resources. These methods still rely heavily on traditional manual grinding and polishing, requiring high operator experience, making them unsuitable for the rapid microstructural inspection needs of the modern era.

[0004] Therefore, those skilled in the art are committed to developing a rapid inspection method for the microstructure of copper and copper alloys to address the deficiencies of the above-mentioned prior art. Summary of the Invention

[0005] In view of the above-mentioned defects of the prior art, the technical problems to be solved by the present invention are: in the current prior art, the etching rate is too fast or too slow, which can easily lead to insufficient corrosion or excessive corrosion, and places high demands on the operator; the etchant produces nitrogen oxides that are harmful to the atmospheric environment and have an impact on the health of the operator, and the etchant contains heavy metal ions that can cause serious environmental pollution; the etchant has no decontamination ability, and during polishing, the dust and impurities on the flannel will interfere with the subsequent chemical etching, resulting in uneven corrosion; the microstructure inspection method mechanically applies a set of methods to all samples, resulting in a waste of resources.

[0006] To achieve the above objectives, the present invention provides, in a first aspect, an etchant for copper and copper alloy microstructures;

[0007] The etching agent comprises the following components: ammonium persulfate, ethanol, sodium silicate, sodium dodecylbenzene sulfonate, and water;

[0008] Wherein, the mass fraction of sodium silicate in the etching agent is 0.14% to 1.37%; the mass fraction of sodium dodecylbenzenesulfonate in the etching agent is 0.14% to 0.83%;

[0009] Furthermore, the mass fraction of ammonium persulfate in the etching agent is 7.33% to 22.5%;

[0010] Furthermore, the mass fraction of ethanol in the etchant is 1.13% to 6.82%;

[0011] Furthermore, the etchant for copper and copper alloy microstructures has the following components in the following proportions: 5g to 9g ammonium persulfate, 1ml to 3ml ethanol, 0.1g to 0.5g sodium silicate, 0.1g to 0.3g sodium dodecylbenzenesulfonate, and 30ml to 60ml water;

[0012] In a specific embodiment of the present invention, the mass fraction of sodium silicate in the etching agent is 0.21%;

[0013] In another specific embodiment of the present invention, the mass fraction of sodium silicate in the etchant is 0.45%;

[0014] In another specific embodiment of the present invention, the mass fraction of sodium silicate in the etchant is 0.14%;

[0015] In another specific embodiment of the present invention, the mass fraction of sodium silicate in the etchant is 1.37%;

[0016] In a specific embodiment of the present invention, the mass fraction of sodium dodecylbenzenesulfonate in the etchant is 0.21%;

[0017] In another specific embodiment of the present invention, the mass fraction of sodium dodecylbenzenesulfonate in the etchant is 0.22%;

[0018] In another specific embodiment of the present invention, the mass fraction of sodium dodecylbenzenesulfonate in the etchant is 0.14%;

[0019] In another specific embodiment of the present invention, the mass fraction of sodium dodecylbenzenesulfonate in the etchant is 0.83%;

[0020] Furthermore, preferably, the water is clean water or distilled water;

[0021] In a specific embodiment of the present invention, the preparation process of the chemical etching agent is as follows:

[0022] Step 1. Place a clean magnetic stirring bar in a clean glass beaker;

[0023] Step 2: Use a graduated cylinder to measure 30ml to 60ml of distilled water and pour it into a clean glass beaker;

[0024] Step 3: Use a pipette to aspirate 1ml to 3ml of analytical grade ethanol, and then place the pipette tip close to the wall of the glass beaker to release the liquid;

[0025] Step 4: Use a precision electronic balance to weigh 5g to 9g of ammonium persulfate, 0.1g to 0.5g of sodium silicate, and 0.1g to 0.3g of sodium dodecylbenzenesulfonate, and add them to a glass beaker in sequence;

[0026] Step 5: Place the glass beaker containing the above substances on a stirring heating table, control the heating temperature at 15° C. to 45° C., and stir for 1 minute to 4 minutes to obtain the prepared etching agent.

[0027] Furthermore, preferably, the heating temperature in step 5 is 25°C-35°C, and the stirring time is 2min-3min;

[0028] A second aspect of the present invention provides a rapid inspection method for the microstructure of copper and copper alloys;

[0029] Step 1, sampling and polishing: First determine whether the surface to be tested is smooth. If the surface to be tested is smooth, cut a sample of appropriate length and proceed directly to step 2. If the surface to be tested is rough, cut a sample of appropriate length from the sample to be tested, press the surface to be tested slightly on the water sandpaper for rough grinding. After rough grinding horizontally for a period of time, switch to the vertical direction and continue rough grinding for a period of time;

[0030] Step 2: Soaking: Immerse the surface of the sample to be tested completely in the etchant for a period of time to remove deep scratches and stains. After soaking, remove the sample and clean the surface to be tested with clean water.

[0031] Step 3, polishing: mechanically polish the sample surface to be tested after immersion for a period of time. After the mechanical polishing is completed, clean the sample surface to be tested with clean water;

[0032] Step 4, chemical etching: Immerse the sample surface to be tested completely in the etchant for chemical etching. After etching for a period of time, remove the sample and clean the surface to be tested with clean water. After cleaning, use absorbent paper to absorb the water remaining on the surface to be tested;

[0033] Step 5: Microstructure photography: Place the sample to be inspected on the stage of the metallographic microscope, select an appropriate magnification, focus, and then photograph the relevant microstructure.

[0034] Furthermore, the time for horizontal coarse grinding in step 1 is 0.5 min to 5 min, and the time for vertical coarse grinding is 0.5 min to 5 min;

[0035] Furthermore, the rotation speed of the water polishing machine in step 1 is 350 r / min to 550 r / min;

[0036] Furthermore, the mesh number of the water sandpaper in step 1 is 360 mesh to 1200 mesh;

[0037] Furthermore, preferably, the time for horizontal coarse grinding in step 1 is 0.5 min to 2 min, and the time for vertical coarse grinding is 0.5 min to 2 min;

[0038] Furthermore, preferably, the rotation speed of the water polishing machine in step 1 is 450 r / min;

[0039] Furthermore, preferably, the mesh size of the water sandpaper in step 1 is 600-1000 mesh;

[0040] Furthermore, the soaking time in step 2 is 0.5 min to 10 min;

[0041] Furthermore, preferably, the soaking time in step 2 is 1 min to 7 min;

[0042] Furthermore, the polishing time in step 3 is 0.5 min to 5 min;

[0043] Furthermore, in step 3, the polishing liquid needs to be added in drop form;

[0044] Furthermore, preferably, the polishing time is 1 min to 3 min;

[0045] Furthermore, preferably, the polishing liquid is a nano-alumina polishing liquid;

[0046] Furthermore, after the polishing in step 3 is completed, it is necessary to immediately carry out chemical etching in step 4 to prevent the formation of an oxide film on the polished surface and change the etching conditions;

[0047] Furthermore, the chemical etching time in step 4 is 0.5 min to 10 min;

[0048] Furthermore, the water used for cleaning in step 4 is distilled water;

[0049] Furthermore, after the chemical etching in step 4 is completed, the etchant must be washed away with clean water immediately to prevent the etchant from continuing to erode;

[0050] Furthermore, the absorbent paper in step 4 should absorb the residual water at the edge of the sample surface to be tested to prevent water stains and absorbent paper fibers from affecting the judgment of the microstructure;

[0051] Furthermore, the magnification of the metallographic microscope in step 5 is 50 to 1500 times;

[0052] By adopting the above scheme, the etching agent and rapid inspection method for the microstructure of copper and copper alloys disclosed in the present invention have the following advantages:

[0053] (1) The etchant for copper and copper alloy microstructures of the present invention has a moderate chemical etching rate, is easy for operators to control, can reduce the occurrence of insufficient corrosion or excessive corrosion, is easy for operators to use, and is easier to obtain uniformly corroded samples, which is convenient for subsequent observation and analysis under a metallographic microscope; the etchant has a certain decontamination ability, which can prevent dust and other impurities on the polishing flannel from interfering with the sample during the polishing process; the etchant of the present invention does not contain nitrogen oxides and heavy metal ions, can be used in places with poor ventilation conditions, has a wider range of applications, has little harm to the environment, and does not pose a health hazard to operators;

[0054] (2) The present invention is a rapid inspection method for the microstructure of copper and copper alloys. The operation steps are simple. Compared with the traditional microstructure inspection method, the method eliminates the tedious inlaying and fine grinding steps. Instead, the method uses an etchant to soak the sample to eliminate deep scratches and stains, freeing the human from the time-consuming and labor-intensive fine grinding work. The method can flexibly select whether to perform polishing according to the condition of the sample to be inspected, thereby avoiding the waste of related resources caused by the mechanical execution of the inspection steps, thereby improving the inspection efficiency. After the etching is completed, absorbent paper is used to absorb moisture from the edge of the surface to be inspected, thereby avoiding the problem of surface oxidation of the surface to be inspected that may be caused by using a hair dryer to blow the moisture off the surface to be inspected.

[0055] In summary, the present invention discloses an etchant and a rapid inspection method for the microstructure of copper and copper alloys, which flexibly execute relevant steps according to the specific conditions of the sample to be tested, thereby achieving rapid inspection while avoiding waste of related resources. The etchant is immersed to eliminate deeper scratches and stains, freeing manual labor from simple and repetitive fine grinding work. The etchant of the present invention has a moderate corrosion rate, is easy for operators to use, rarely causes insufficient or excessive corrosion, has little harm to the environment, poses no health risks to operators, can be used in poorly ventilated places, and has a wide range of uses.

[0056] The concept, specific technical solutions and technical effects of the present invention will be further described below in conjunction with specific implementation methods to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a metallographic photograph at 200X of Example 1 of the present invention;

[0058] Figure 2 This is a metallographic photograph at 100X of Example 1 of the present invention;

[0059] Figure 3 This is a metallographic photograph at 100X of Example 2 of the present invention;

[0060] Figure 4 This is a metallographic photograph at 200X of Example 2 of the present invention. DETAILED DESCRIPTION

[0061] The following describes several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, which are for illustrative purposes only and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0062] Example 1: Observe the metallographic microstructure of TP2 O60 (Cu+Ag≥99.90%, P: 0.015-0.040%) copper and copper alloy seamless tubes for air conditioning and refrigeration equipment.

[0063] Step 1: Prepare the chemical etchant. Place a dry, clean magnetic stir bar in a dry, clean glass beaker. Then, use a graduated cylinder to measure 40ml of distilled water and pour it into the beaker. Use a pipette to draw in 1ml of analytical grade ethanol. Place the pipette tip against the wall of the beaker and dispense the liquid. Next, weigh 7g of ammonium persulfate, 0.1g of sodium silicate, and 0.1g of sodium dodecylbenzenesulfonate on a precision electronic balance. Once the beaker is fully charged, place it on a magnetic stirring heating block at a temperature between 25°C and 35°C. Stir for 2 minutes. After heating and stirring, the etchant is obtained.

[0064] Step 2: Then evaluate the copper and copper alloy seamless pipes for air conditioning and refrigeration equipment. The surface of the test sample is smooth and does not require polishing. In this specific implementation, a section with a polished surface area of ​​400mm is directly cut out. 2 For samples with a height of 40mm, place the test sample in the etchant and soak it for 3 minutes to eliminate deeper scratches and stains. After soaking, the test sample is polished. The polishing liquid is nano-alumina polishing liquid. The polishing machine rotates at 400r / min and the polishing liquid is dripped onto the polishing flannel. The nano-alumina abrasive particles in the polishing liquid continuously wash the grinding surface, thereby achieving the purpose of polishing. After polishing, the test surface is cleaned with clean water. After cleaning, the remaining clean water on the test surface is dried with absorbent paper. The test surface is then quickly placed in the etchant for chemical etching. The reason for quickly placing it in the etchant is to prevent the formation of an oxide film on the polished surface and to prevent the oxide film from changing the etching conditions.

[0065] Step 3: Chemical etching is performed for 1.5 minutes. The deformation disturbance layer on the polished surface is first dissolved, followed by the appearance of the true microstructure. The microstructure of TP2 O60 is composed of numerous grains with different orientations. Grain boundaries exist between the grains. Unlike the atoms within the grains, the atoms at these boundaries are irregularly arranged and have high free energy, causing them to erode rapidly, forming grooves. The grains themselves are only slightly etched, revealing polygonal grains. This level of etching is considered sufficient.

[0066] Step 4: After chemical etching is completed, it is necessary to promptly rinse with distilled water to prevent the etchant from remaining on the surface of the test sample and causing excessive corrosion. After the distilled water rinse is completed, use absorbent paper to absorb any remaining water stains on the edge of the test surface. On the one hand, this prevents the remaining water stains from being mistakenly identified as additional phases, affecting the correct inspection. On the other hand, absorbing the edges of the test surface is to prevent the fibers of the absorbent paper from affecting the test surface and to avoid oxidation caused by heating and air drying.

[0067] Step 5. Finally, the sample that has undergone the above treatment is stably placed on the stage of a ZEEISS Axio VertA1 metallographic microscope, focused and photographed, and finally obtained Picture 1 with a magnification of 300 times and Picture 2 with a magnification of 100 times. The obtained metallographic images of the microstructure are clear, the grain structure is complete, and the grain boundaries are very clear, with good inspection effect.

[0068] In summary, the implementation time of step 1 of this embodiment is 5 minutes; step 2 is 6 minutes; step 3 is 1.5 minutes; step 4 is 0.5 minutes; and the total time before specific observation is 13 minutes.

[0069] Example 2: Observe the metallographic structure of the H65 (Cu: 63.0-68.5%, Fe≤0.07%, Pb≤0.09%, Zn balance) brass strip microstructure.

[0070] Step 1: Prepare the chemical etchant. Place a dry, clean magnetic stir bar in a dry, clean glass beaker. Then, use a graduated cylinder to measure 35ml of distilled water and pour it into the beaker. Use a pipette to draw in 2ml of analytical grade ethanol. Place the pipette tip against the wall of the beaker to release the liquid. Next, weigh 8g of ammonium persulfate, 0.2g of sodium silicate, and 0.1g of sodium dodecylbenzenesulfonate on a precision electronic balance. Once all the ingredients are in the beaker, place it on a magnetic stirring heating table. Control the heating temperature between 25°C and 35°C and stir for 2 minutes. After heating and stirring, the etchant is obtained.

[0071] Step 2: Then evaluate the H65 brass strip. The surface quality of the brass strip is poor and needs to be polished. First, a section of sample needs to be cut from the brass strip. In this specific implementation, a section with a polished surface area of ​​200mm was cut. 2 , a sample with a length of 50mm. Next, the sample is polished. 1000-mesh water sandpaper is selected and fixed on the turntable of the water grinder. The speed of the water grinder is 450r / min. The operator presses the sample slightly to make the sample fully contact with the water sandpaper on the water grinder, and performs horizontal rough grinding. The horizontal rough grinding time is 1min. After the horizontal rough grinding is completed, the sample is subjected to vertical rough grinding. The vertical rough grinding time is 1min. After polishing, the sample is placed in the etchant and immersed. The surface to be tested is completely immersed in the etchant. The immersion time is 3min. After the immersion is completed, the surface to be tested is cleaned with clean water. After cleaning, mechanical polishing is performed. The polishing liquid is nano-alumina polishing liquid. The speed of the polishing machine is 400r / min. The polishing liquid is dripped onto the polishing velvet cloth. The nano-alumina abrasive particles in the polishing liquid continuously wash the surface of the grinding surface, thereby achieving the purpose of polishing; after polishing is completed, the surface to be tested is cleaned with clean water. After cleaning, the remaining clean water on the surface to be tested is absorbed with absorbent paper; then the surface to be tested is quickly placed in the etchant for chemical etching. The reason for quickly placing it in the etchant is to prevent the formation of an oxide film on the polished surface to prevent the oxide film from changing the etching conditions.

[0072] Step 3: Chemical etching for 2 minutes. The etching of H65 is mainly an electrochemical corrosion process. Different phases have different electrode potentials due to their different composition and structure. When the polished surface is immersed in the etchant, many pairs of tiny local batteries are formed. Zn has a relatively negative electrode potential and acts as the anode. It dissolves during etching, and these micro-areas on the polished surface become concave and rough. Cu has a positive electrode potential and acts as the cathode. Under normal electrochemical action, it is not corroded and maintains its original smooth surface. Therefore, after etching, Zn appears dark under a metallographic microscope, while Cu appears bright under a metallographic microscope.

[0073] Step 4: After the chemical etching is completed, the surface to be tested must be cleaned with distilled water immediately to prevent the etchant from remaining on the surface and causing localized excessive corrosion. After the distilled water cleaning is completed, use absorbent paper to absorb any remaining water stains on the edge of the surface to be tested. This is to prevent the remaining water stains from being mistakenly identified as additional phases, which could affect the correct inspection. Blotting the edges of the surface to be tested is also to prevent the fibers of the absorbent paper from affecting the surface to be tested. Avoid using a hair dryer to dry any remaining water to avoid the possibility of oxidation of the observation surface caused by air drying.

[0074] Step 5. Finally, the treated sample was stably placed on the stage of a ZEEISS Axio VertA1 metallographic microscope for focusing and photographing. Finally, Picture 3 with a magnification of 100x and Picture 4 with a magnification of 200x were obtained. The metallographic microstructure of the brass strip obtained has high resolution between tissues, clear structure, complete grain display, and very clear grain boundaries.

[0075] In summary, the implementation time of step 1 of this embodiment is 5 minutes; step 2 is 8 minutes; step 3 is 3 minutes; step 4 is 1 minute; and the total time before specific observation is 17 minutes.

[0076] Example 3: Observation of the metallographic microstructure of TP2 O60 (Cu+Ag≥99.90%, P: 0.015-0.040%) copper and copper alloy seamless tubes for air conditioning and refrigeration equipment.

[0077] Step 1: Prepare the chemical etchant. Place a dry, clean magnetic stir bar in a dry, clean glass beaker. Then, use a graduated cylinder to measure 60ml of distilled water and pour it into the beaker. Use a pipette to draw in 3ml of analytical grade ethanol. Place the pipette tip against the wall of the beaker to dispense the liquid. Next, weigh 9g of ammonium persulfate, 0.1g of sodium silicate, and 0.1g of sodium dodecylbenzenesulfonate on a precision electronic balance. Once the beaker is fully charged, place it on a magnetic stirring heating block at a temperature between 25°C and 35°C. Stir for 2 minutes. After heating and stirring, the etchant is obtained.

[0078] The mass fraction of sodium silicate in the prepared etchant is 0.14%, and the mass fraction of sodium dodecylbenzenesulfonate in the etchant is 0.14%.

[0079] The subsequent operation steps are the same as steps 2, 3, 4, and 5 in Example 1. The metallographic microstructure obtained by using the above-mentioned etching agent is the same as that of the Figure 1 、 Figure 2 Not much difference.

[0080] Example 4: Observe the metallographic microstructure of H65 (Cu: 63.0-68.5%, Fe≤0.07%, Pb≤0.09%, Zn balance) brass strip.

[0081] Step 1: Prepare the chemical etchant. Place a dry, clean magnetic stir bar in a dry, clean glass beaker. Then, use a graduated cylinder to measure 30ml of distilled water and pour it into the beaker. Use a pipette to draw in 1ml of analytical grade ethanol. Place the pipette tip against the wall of the beaker and dispense the liquid. Next, weigh 5g of ammonium persulfate, 0.5g of sodium silicate, and 0.3g of sodium dodecylbenzenesulfonate on a precision electronic balance. Once the beaker is fully charged, place it on a magnetic stirring heating block at a temperature between 25°C and 35°C. Stir for 2 minutes. After heating and stirring, the etchant is obtained.

[0082] The mass fraction of sodium silicate in the prepared etchant is 1.37%, and the mass fraction of sodium dodecylbenzenesulfonate in the etchant is 0.83%.

[0083] The subsequent operation steps are the same as steps 2, 3, 4, and 5 in Example 2. The metallographic microstructure obtained by using the above-mentioned etching agent is the same as that of the Figure 3 、 Figure 4 Not much difference.

[0084] Comparative Example 5: Sampling The metallographic structure of the H65 (Cu: 63.0-68.5%, Fe≤0.07%, Pb≤0.09%, Zn balance) brass strip microstructure was observed using a conventional sampling method.

[0085] Step 1: Sampling and Mounting: First, sample the brass strip and mount it. Select a representative area, approximately 15mm in diameter and 10mm in height. Once the mounting machine temperature reaches 130-140°C, proceed with the subsequent steps. First, adjust the handwheel so that the lower die is parallel to the lower platform. Then, place the specimen, observation side down, in the center of the lower die. Turn the handwheel counterclockwise 10-12 times to lower the lower die and sample. Add resin filler. Then, press the upper die onto the filler. Apply downward pressure with your left fingers while simultaneously turning the handwheel counterclockwise with your right hand until its upper surface is lower than the upper platform. Quickly close the cover. Then, immediately and rapidly turn the handwheel clockwise until the pressure light illuminates. At this point, add 1-2 more turns. At the correct temperature and pressure, time for 5-10 minutes. Once pressurization is complete, sampling can begin.

[0086] The sampling process is as follows: Remove pressure: Turn the handwheel counterclockwise to relieve pressure until the pressure light goes out; then turn it counterclockwise five more times to create space for demolding; Demolding: Turn the octagonal knob clockwise to push the upper mold plate downward to demold the sample; then, turn the octagonal knob counterclockwise again to open the cover; then, turn the handwheel clockwise to push out the upper mold until the lower edge of the upper mold is parallel to the lower platform, then use a wooden hammer to knock the upper mold off; place the upper mold in the corner of the upper platform on the right side of the inlay chamber; continue to raise the lower mold until the sample is fully exposed and can be removed using the same method as for removing the upper mold. It is important to note that the sample temperature is currently as high as 130°C, making it impossible to handle it directly. The sample must be allowed to cool naturally to room temperature in the air before further operations can be performed. The entire step 1 takes 30 minutes.

[0087] Step 2, polishing: Select 360 mesh, 600 mesh, 800 mesh, 1000 mesh, 1200 mesh, and 1500 mesh water sandpaper in sequence to polish the observation surface of the mounted specimen. During the operation, whenever the water sandpaper mesh needs to be changed, the contact direction between the specimen and the water grinder is changed 180 degrees so that the scratches left on the specimen surface by the previous mesh can be eliminated; after completing the polishing operation of the above meshes, perform polishing;

[0088] Step 3: Polishing: Mechanical polishing is performed using a nano-alumina polishing liquid. The polishing machine rotates at 450 r / min and the polishing liquid is sprayed onto the polishing cloth in a thin stream. The nano-alumina abrasive particles in the polishing liquid continuously wash the surface of the polished surface, thereby achieving the purpose of polishing. After polishing, the sample to be tested needs to be quickly placed in the etchant for chemical etching. The reason for quickly placing it in the etchant is to prevent the formation of an oxide film on the polished surface, which will change the etching conditions.

[0089] Step 4: Prepare the etchant and perform the etching process: Prepare the chemical etchant by placing a dry, clean magnetic stir bar in a dry, clean glass beaker. Use a graduated cylinder to measure 35ml of distilled water and pour it into the beaker. Use a pipette to draw in 2ml of analytical grade ethanol. Place the pipette tip against the wall of the beaker to release the liquid. Next, weigh 8g of ammonium persulfate, 0.2g of sodium silicate, and 0.1g of sodium dodecylbenzenesulfonate on a precision electronic balance. Once the glass beaker is filled with all the ingredients, place it on a magnetic stirring heating table. Control the heating temperature between 25°C and 35°C and stir for 2 minutes. After heating and stirring, the etchant is obtained.

[0090] Step 5: Observation under a metallographic microscope: Finally, the sample that has undergone the above treatment is stably placed on the stage of a ZEEISS Axio VertA1 metallographic microscope for focusing and photographing.

[0091] In summary, the implementation time of step 1 of this embodiment is 30 minutes; step 2 is 15 minutes; step 3 is 3 minutes; step 4 is 5 minutes; and the total time before specific observation is 53 minutes.

[0092] Comparative Example 6 employed a conventional etchant comprising: 7.2 g of chromium trichloride; 12 g of potassium dichromate; 7 mL of acetic acid; 58 mL of sulfuric acid; and 45 mL of water. The procedure of Example 2 was followed. Because the conventional etchant was used, the preparation of the chemical etchant of the present invention in Step 1 of the Example was unnecessary. Subsequent operations were performed directly. When Comparative Example 6 reached Step 2: polishing in Example 2, a large number of impurities from the polishing cloth were already present on the surface of the sample to be observed, causing scratches. During Step 5: metallographic microstructure observation in Example 2, the sample surface was excessively scratched, making it impossible to capture a convincing, clear microstructure image. The metallographic micrographs obtained in Comparative Example 6 were unusable. Furthermore, the conventional etchant contained potassium dichromate, a heavy metal ion that is extremely polluting and causes significant environmental damage.

[0093] In summary, comparing Example 2 with Comparative Example 5, Example 1, which employs the technical solution of the present invention, only took 30 minutes to complete the sampling and mounting operation in Comparative Example 5 compared to the prior art. This means that Example 2 saves 312% of the time required for the entire metallographic microstructure inspection process compared to Comparative Example 5. This reduces the time required and allows for faster acquisition of metallographic microstructure images of the sample.

[0094] Comparing Example 2 with Comparative Example 6, Example 2 using the technical solution of the present invention does not contain heavy metal ions in the etchant of Comparative Example 6, and is more environmentally friendly.

[0095] Furthermore, the etchant prepared in Example 2 of the present invention, wherein the relevant components thereof can effectively remove pollutants attached to the sample surface, and remove relevant impurities on the polishing cloth during the polishing process, so that clear and usable metallographic microstructure images without deep scratches can be taken in the end.

[0096] In summary, the technical solution of this patent determines the relevant steps according to the specific situation of the sample to be tested, realizes rapid inspection, and avoids the waste of relevant resources. It uses a water grinder and etchant immersion to eliminate deeper scratches and stains, and liberates manual labor from simple and repetitive metallographic polishing work; and the etchant of the present invention has a moderate corrosion rate, is easy for operators to use, and reduces insufficient or excessive corrosion. The etchant of the present invention has a decontamination ability, which can avoid the interference of dust or impurities on the flannel during polishing on subsequent etching. The etchant has little harm to the environment and has no health risks to operators. It can be used in poorly ventilated places and has a wide range of uses.

[0097] The above describes in detail the preferred embodiments of the present invention. It should be understood that numerous modifications and variations based on the concepts of the present invention can be made by those skilled in the art without inventive effort. Therefore, any technical solution that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. An etchant for copper and copper alloy microstructures, characterized in that: The etching agent is composed of the following components: ammonium persulfate, ethanol, sodium silicate, sodium dodecylbenzene sulfonate, and water; Wherein, in the etching agent, the mass fraction of sodium silicate is 0.14% to 1.37%; the mass fraction of sodium dodecylbenzenesulfonate is 0.14% to 0.83%; the mass fraction of ammonium persulfate is 7.33% to 22.5%; and the mass fraction of ethanol is 1.13% to 6.82%.

2. The etchant according to claim 1, wherein The ratio of the etching agent is 5g-9g of ammonium persulfate, 1ml-3ml of ethanol, 0.1g-0.5g of sodium silicate, 0.1g-0.3g of sodium dodecylbenzenesulfonate, and 30ml-60ml of water; The ammonium persulfate was of analytical grade; the ethanol was of analytical grade.

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