Electrolytic extraction method and detection method for large particle inclusions in titanium and titanium alloys
By using inorganic electrolytes and electrolytic cells to extract large inclusions in titanium and titanium alloys, the safety and pollution problems of traditional methods have been solved, achieving non-toxic and pollution-free extraction and characterization of inclusions, thus improving the quality of ingots.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
- Filing Date
- 2026-03-04
- Publication Date
- 2026-05-29
AI Technical Summary
Traditional electrolytic extraction methods can only be used on steel, employing strong acid or alkaline solutions, posing safety hazards and causing pollution to inclusions. They also have stringent environmental requirements and cannot effectively extract and characterize large particle inclusions in titanium and titanium alloys.
An inorganic electrolyte formulation, including ferrous sulfate, zinc chloride, and sodium citrate, was used to prepare the electrolyte. The sample was dissolved at the anode in the electrolytic cell, and the anode mud was collected, washed, and filtered. The morphology and composition of the inclusions were observed using scanning electron microscopy.
It achieves non-toxic and pollution-free inclusion extraction, ensures inclusion integrity, improves the accuracy and safety of characterization, reduces operational complexity, and can quantify inclusion content to improve ingot quality.
Smart Images
Figure CN122105526A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of metal electrochemistry technology, specifically relating to an electrolytic extraction method and a detection method for large particle inclusions in titanium and titanium alloys. Background Technology
[0002] Inclusions that are not fully dissolved during the smelting process remain in the ingot, significantly impacting subsequent processing performance. The presence of inclusions can cause defects such as peeling and wrinkling on the surface of rolled products, greatly limiting their application. Therefore, to improve the quality of ingots and rolled products, it is necessary to comprehensively characterize the content, size, and morphology of inclusions in pure titanium ingots. This requires extracting the inclusions from the pure titanium ingots, classifying their size, and then observing their morphology and composition using scanning electron microscopy.
[0003] Traditional electrolytic extraction is generally used in steel and has the following disadvantages: 1. It can only be used for steel, with a narrow range of applications; 2. It uses strong acid or alkaline solutions as electrolytes, which can damage inclusions during the electrolysis process; 3. The electrolysis products can easily contaminate inclusions; 4. It has strict requirements for the pH and temperature conditions of the electrolysis environment and requires high sample pretreatment; 5. Traditional electrolytes contain highly corrosive reagents such as hydrochloric acid and sulfuric acid, posing a safety hazard to operators.
[0004] CN116202851A discloses a non-destructive extraction method for inclusions in titanium alloys, comprising the following steps: Step 1: Pre-treating the surface of the titanium alloy sample to remove impurities from the surface and surface structure; Step 2: Placing the pre-treated titanium alloy sample in an acid pickling solution for 1-2 hours; Step 3: Inert gas is introduced into the electrolyte, and under inert gas protection, electrolysis is performed using the titanium alloy sample as the anode and graphite as the cathode; Step 4: The titanium alloy sample with anode mud obtained after electrolysis in Step 3 is ultrasonically cleaned in anhydrous ethanol to obtain a cleaning solution; Step 5: The electrolyte from Step 3 and the cleaning solution from Step 4 are mixed... After mixing the washing solutions, centrifugation is performed. The lower suspension obtained after centrifugation is then ultrasonically cleaned. This centrifugation and ultrasonic cleaning process is repeated 3-4 times. Finally, after centrifugation, the sample is filtered to obtain the filtrate, which is then vacuum-dried to obtain the inclusions. The specific pretreatment process in step 1 is as follows: the titanium alloy sample is ground and polished, then washed with water, and then ultrasonically cleaned in anhydrous ethanol. Finally, it is dried to complete the pretreatment. The electrolyte in step 3 is a mixture of 1%-3% tetramethylammonium chloride, 1%-3% sodium chloride, 3%-8% triethanolamine, 2%-6% glycerol, and 85%-90% anhydrous methanol by mass fraction. However, this method requires acid washing of the sample and uses an organic electrolyte, which poses safety risks. In addition, it requires electrolysis under an inert gas atmosphere, making the operation complex. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention develops a novel, non-toxic, and pollution-free electrolysis method for inclusions in pure titanium or titanium alloy ingots, with a simple electrolyte composition. The sample matrix is dissolved using a specially designed electrolysis device. After filtration, washing, and size grading, the prepared sample is observed under a scanning electron microscope to characterize the inclusion content, size grading, and morphology.
[0006] To address the problems of existing technologies, this invention first provides an electrolytic extraction method for large particle inclusions in titanium and titanium alloys, comprising the following steps:
[0007] A. Preparation of electrolyte: Prepare electrolyte using ferrous sulfate, zinc chloride, sodium citrate, and water;
[0008] B. Sample preparation: After obtaining the sample from a pure titanium ingot or titanium alloy ingot, weld a nut to the top, and use 200~2000# sandpaper to polish the sample surface until smooth, then ultrasonically clean and dry.
[0009] C. Connection device setting parameters: Add electrolyte to the electrolytic cell, wrap the wire mesh around the outside of the electrolytic cell, suspend the dried sample on the pure copper connecting rod at the top of the electrolytic cell through the nut, so that the sample is completely immersed in the electrolyte, connect the anode and cathode, with the wire mesh connected to the cathode and the sample connected to the anode, turn on the power, set the voltage to 10~50V, the current to 5~60A, and the electrolysis time period to 10~20 days;
[0010] D. Collect anode mud: After electrolysis, collect the anode mud deposited at the bottom of the electrolyte and clean it with ultrasonic waves;
[0011] E. Washing and Filtration: Collect the anode mud after ultrasonic cleaning, stir and wash it, then pour the anode mud into a coarse sieve. After the inclusions pass through the coarse sieve, they pass through sieves of different apertures in sequence to complete the size classification of the inclusions.
[0012] In the electrolytic extraction method for large particle inclusions in titanium and titanium alloys, in step A, the electrolyte contains 1-10 wt% ferrous sulfate, 1-15 wt% zinc chloride, 0.5-1.5 wt% sodium citrate, and the remainder is water.
[0013] Preferably, in the electrolytic extraction method for large particle inclusions in titanium and titanium alloys described above, in step A, the electrolyte contains 4-7 wt% ferrous sulfate, 1-3 wt% zinc chloride, 0.8-1.2 wt% sodium citrate, and the balance is deionized water.
[0014] In the electrolytic extraction method for large particle inclusions in titanium and titanium alloys, the sample size in step B is 50~60mm×50~60mm×120~150mm.
[0015] In the electrolytic extraction method for large particle inclusions in titanium and titanium alloys, step B involves sequentially polishing the sample surface with 200-mesh, 400-mesh, 800-mesh, and 1200-mesh sandpaper to remove the oxide scale from the sample surface.
[0016] In the electrolytic extraction method for large particle inclusions in titanium and titanium alloys, step C sets the voltage to 20-30V, the current to 5-10A, and the electrolysis time period to 14-16 days.
[0017] In the electrolytic extraction method for large particle inclusions in titanium and titanium alloys, in step C, the mass ratio of electrolyte to sample is 10~15:1.
[0018] In the electrolytic extraction method for large particle inclusions in titanium and titanium alloys, the top nut in step B is of type M12.
[0019] In the electrolytic extraction method for large particle inclusions in titanium and titanium alloys, the ultrasonic cleaning time in step B is 1~10 min.
[0020] In the electrolytic extraction method for large particle inclusions in titanium and titanium alloys, step B involves ultrasonic cleaning with anhydrous ethanol.
[0021] In step D, the ultrasonic cleaning time is 1~10 minutes.
[0022] In the electrolytic extraction method for large particle inclusions in titanium and titanium alloys, step D involves ultrasonic cleaning with water.
[0023] In the electrolytic extraction method for large particle inclusions in titanium and titanium alloys, in step E, the pore size of the coarse sieve is 0.8~1.2mm, and the pore sizes of the sieves that pass through sequentially are 250~300μm, 120~160μm and 60~100μm.
[0024] Based on the above-mentioned electrolytic extraction method, the present invention also provides a method for detecting large particle inclusions in titanium and titanium alloys, which, in addition to steps A to E mentioned above, also includes the following steps:
[0025] F. Sample preparation and observation: The size-graded inclusions are pasted onto conductive adhesive, which is then pasted onto aluminum ingots. Their morphology is observed under an optical microscope, and their morphology and composition are observed under a scanning electron microscope.
[0026] In this invention, deionized water is generally used.
[0027] The beneficial effects of this invention are:
[0028] This invention provides a customized inorganic electrolyte for pure titanium or titanium alloy ingots. The sample, acting as the anode, loses electrons, causing the matrix to dissolve continuously. Inclusions then detach and settle at the bottom of the electrolytic cell, forming anode mud. After washing and filtration, complete inclusions in the pure titanium or titanium alloy ingots can be obtained, providing a method for characterizing the internal quality of these ingots. Furthermore, the electrolyte is an inorganic reagent with a simple, non-toxic, and environmentally friendly formulation. This invention allows for the complete extraction of inclusions from the ingot, ensuring accurate characterization. During sample preparation, inclusions are adhered to conductive adhesive, which can be applied to small aluminum ingots, resulting in good sample conductivity and eliminating the need for carbon or gold spraying before scanning electron microscopy.
[0029] This invention can characterize the inclusion content level inside pure titanium or titanium alloy ingots, evaluate the quality of pure titanium or titanium alloy ingots, and predict the surface quality of subsequent rolled products. This invention can quantitatively characterize the inclusion content level inside pure titanium or titanium alloy ingots, and adjust the raw material ratio and process parameters accordingly to improve the internal quality of pure titanium or titanium alloy ingots and reduce surface defects in rolled products. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of the electrolysis device in this invention.
[0031] Figure 2 The image shows the morphology of the inclusions obtained by electrolytic extraction under a light microscope.
[0032] Figure 3 The image shows the morphology of the inclusions obtained by electrolytic extraction under a scanning electron microscope.
[0033] Figure 4 This is the composition spectrum of the inclusions obtained by electrolytic extraction under EDS. Detailed Implementation
[0034] Specifically, an electrolytic extraction method and detection method for large particle inclusions in titanium and titanium alloys include the following steps:
[0035] A. Prepare the electrolyte: Use 1~10wt% ferrous sulfate, 1~15wt% zinc chloride, 0.5~1.5wt% sodium citrate and the balance deionized water to prepare the electrolyte;
[0036] B. Sample preparation: After obtaining a sample with dimensions of 50~60mm×50~60mm×120~150mm from a pure titanium ingot or titanium alloy ingot, weld an M12 nut to the top. Grind the sample surface to a smooth finish using 200-grit, 400-grit, 800-grit, and 1200-grit sandpaper in sequence to remove the oxide scale on the sample surface. Then, use anhydrous ethanol for ultrasonic cleaning for 1~10 minutes, dry, and weigh to obtain the weight of the dried sample.
[0037] C. Connection device setting parameters: Add electrolyte to the electrolytic cell, wrap the wire mesh around the outside of the electrolytic cell, suspend the dried sample on the pure copper connecting rod at the top of the electrolytic cell through the nut, so that the sample is completely immersed in the electrolyte. The mass ratio of electrolyte to sample is generally 10~15:1. Connect the anode and cathode, with the wire mesh connected to the cathode and the sample connected to the anode. Turn on the power supply and set the voltage to 10~50V, the current to 5~60A, and the electrolysis time period to 10~20 days.
[0038] D. Collecting anode mud: After electrolysis, collect the anode mud deposited at the bottom of the electrolyte, and use deionized water to ultrasonically clean it for 1-10 minutes; then ultrasonically clean the remaining electrolysis sample in deionized water for 1-10 minutes, dry it, weigh it, and obtain the weight of the dried remaining electrolysis sample.
[0039] E. Washing and filtration: Collect the anode mud after ultrasonic cleaning, stir and wash it, then pour the anode mud into a coarse sieve with a pore size of 0.8~1.2mm, add deionized water on top to allow the inclusions to pass through the sieve, and then pass it through sieves with different pore sizes of 250~300μm, 120~160μm and 60~100μm in sequence to complete the inclusion size classification;
[0040] F. Sample preparation and observation: The size-graded inclusions are pasted onto conductive adhesive, which is then pasted onto aluminum ingots. Their morphology is observed under an optical microscope, and their morphology and composition are observed under a scanning electron microscope.
[0041] During the electrolysis process of this invention, the sample, acting as the anode, loses electrons to form Ti. 4+ Ti 4+ It reacts with water to form TiO2·2H2O. The specific reaction at the anode is as follows: Ti - 4e - → Ti 4+ Ti 4+ + 4H₂O → TiO₂·2H₂O + 4H + The wire mesh surrounding the electrolytic cell serves as the cathode, containing Zn. 2+ and Fe 2+ The cathode reaction involves the formation of Fe and Zn, which are adsorbed onto the iron wire mesh after gaining electrons. The specific reaction is as follows: Zn 2+ + 2e - → Zn, Fe 2+ + 2e - → Fe.
[0042] In the electrolysis experiment, the core extraction targets are typical inclusions of titanium oxides and elements such as aluminum, magnesium, silicon, and calcium. These oxides exhibit excellent thermodynamic stability, and under the process conditions applied in this invention, the influence of reaction kinetics is negligible. The probability of such interactions is extremely low, therefore they will not be reduced by ferrous ions (Fe²⁺) or zinc ions (Zn²⁺). The method of this invention has almost no impact on the quantitative analysis results and morphological characteristics of the inclusions, and will not compromise the overall reliability and validity of the experimental conclusions.
[0043] The method of this invention accurately measures the weight of the sample before and after electrolysis, thereby determining the weight of the sample electrolyzed. This weight can be compared with the inclusion content to obtain the inclusion content density of the sample, in mg / 10kg.
[0044] The present invention will be further described in detail below through embodiments, but the scope of protection of the present invention is not limited to the embodiments described herein.
[0045] Example 1
[0046] In this embodiment, a TA2 ingot sample is used as the working electrode for electrolytic extraction, and the specific steps include:
[0047] 1. Prepare the electrolyte
[0048] Prepare the inorganic electrolyte solution by mixing 15L of deionized water, 750g of ferrous sulfate, 375g of zinc chloride, and 150g of sodium citrate until dissolved, and then pouring it into the electrolytic cell.
[0049] 2. Sample preparation
[0050] Take a 50×50×120mm sample from the head of the TA2 pure titanium ingot, weld an M12 nut to the top, and then polish the sample surface with 200~2000 grit sandpaper until it is smooth. Ultrasonically clean it for 3 minutes in anhydrous ethanol environment, and after drying, weigh it. The actual weight is 1.393kg.
[0051] 3. Connect the device, set the parameters, and begin electrolysis.
[0052] After adding all the electrolyte prepared in step 1 to the electrolytic cell, wrap the wire mesh around the outermost part of the cell. Suspend the sample from the pure copper connecting rod at the top of the cell using a nut, ensuring the sample is fully immersed in the electrolyte. Correctly connect the anode and cathode, with the wire mesh connected to the cathode and the sample to the anode. Turn on the power. Set the voltage to 22.5V, the current to 8A, and the electrolysis time to 15 days. Figure 1 As shown.
[0053] 4. Collect anode mud
[0054] After electrolysis, the anode mud deposited at the bottom of the electrolyte was collected in a beaker and ultrasonically cleaned in deionized water for 5 minutes. The electrolysis residue was ultrasonically cleaned in deionized water for 5 minutes, dried, and weighed. The weight of the electrolysis residue was 1.108 kg.
[0055] 5. Washing and filtering
[0056] The collected ultrasonically cleaned anode mud was stirred and washed. The anode mud in the beaker was poured into a coarse sieve with a pore size of 1 mm. Deionized water was added on top to allow the inclusions to pass through the sieve. The resulting inclusions were then passed through sieves with pore sizes of 300 μm, 140 μm, and 80 μm in sequence to complete the size classification of the inclusions.
[0057] 6. Sample preparation and observation
[0058] The collected inclusions were adhered to conductive adhesive, which was then attached to small aluminum ingots. Their morphology was observed under an optical microscope, and their morphology and composition were examined under a scanning electron microscope. The results are as follows: Figures 2-4As shown, the method of the present invention can observe the three-dimensional morphology of inclusions and perform composition scanning under an electron microscope, ensuring that complete inclusions are obtained; the electrolysis process is safe and harmless.
Claims
1. A method for electrolytic extraction of large particle inclusions in titanium and titanium alloys, characterized in that: Includes the following steps: A. Preparation of electrolyte: Prepare electrolyte using ferrous sulfate, zinc chloride, sodium citrate, and water; B. Sample preparation: After obtaining the sample from a pure titanium ingot or titanium alloy ingot, weld a nut to the top, and use 200~2000# sandpaper to polish the sample surface until smooth, then ultrasonically clean and dry. C. Connection device setting parameters: Add electrolyte to the electrolytic cell, wrap the wire mesh around the outside of the electrolytic cell, suspend the dried sample on the pure copper connecting rod at the top of the electrolytic cell through the nut, so that the sample is completely immersed in the electrolyte, connect the anode and cathode, with the wire mesh connected to the cathode and the sample connected to the anode, turn on the power, set the voltage to 10~50V, the current to 5~60A, and the electrolysis time period to 10~20 days; D. Collect anode mud: After electrolysis, collect the anode mud deposited at the bottom of the electrolyte and clean it with ultrasonic waves; E. Washing and Filtration: Collect the anode mud after ultrasonic cleaning, stir and wash it, then pour the anode mud into a coarse sieve. After the inclusions pass through the coarse sieve, they pass through sieves of different apertures in sequence to complete the size classification of the inclusions.
2. The electrolytic extraction method for large particle inclusions in titanium and titanium alloys according to claim 1, characterized in that: In step A, the electrolyte contains 1-10 wt% ferrous sulfate, 1-15 wt% zinc chloride, 0.5-1.5 wt% sodium citrate, and the remainder is water.
3. The electrolytic extraction method for large particle inclusions in titanium and titanium alloys according to claim 2, characterized in that: In step A, the electrolyte contains 4-7 wt% ferrous sulfate, 1-3 wt% zinc chloride, 0.8-1.2 wt% sodium citrate, and the remainder is deionized water.
4. The electrolytic extraction method for large particle inclusions in titanium and titanium alloys according to claim 1, characterized in that: In step B, the size of the sample taken is 50~60mm×50~60mm×120~150mm.
5. The electrolytic extraction method for large particle inclusions in titanium and titanium alloys according to claim 1, characterized in that: In step B, the sample surface is polished to a smooth finish using sandpaper of 200 mesh, 400 mesh, 800 mesh and 1200 mesh in sequence to remove the oxide scale on the sample surface.
6. The electrolytic extraction method for large particle inclusions in titanium and titanium alloys according to claim 1, characterized in that: In step C, the voltage is set to 20~30V, the current to 5~10A, and the electrolysis time period is 14~16 days.
7. The electrolytic extraction method for large particle inclusions in titanium and titanium alloys according to claim 1, characterized in that: In step C, the mass ratio of electrolyte to sample is 10~15:
1.
8. The electrolytic extraction method for large particle inclusions in titanium and titanium alloys according to claim 1, characterized in that: At least one of the following must be met: In step B, the top nut is an M12. In step B, the ultrasonic cleaning time is 1~10 minutes; In step B, anhydrous ethanol is used for ultrasonic cleaning; In step D, the ultrasonic cleaning time is 1~10 minutes; In step D, ultrasonic cleaning is performed using water.
9. The electrolytic extraction method for large particle inclusions in titanium and titanium alloys according to claim 1, characterized in that: In step E, the coarse screen has an aperture of 0.8~1.2mm, and the screens that pass through in sequence have apertures of 250~300μm, 120~160μm and 60~100μm.
10. A method for detecting large particle inclusions in titanium and titanium alloys, characterized in that: Based on claims 1 to 8, the method further includes the following steps: F. Sample preparation and observation: The size-graded inclusions are pasted onto conductive adhesive, which is then pasted onto aluminum ingots. Their morphology is observed under an optical microscope, and their morphology and composition are observed under a scanning electron microscope.