Determination method of Ce in Al-4Cu-2Ce alloy

Abstract

The invention relates to the technical field of alloy chemical component detection, in particular to a method for determining Ce in an Al-4Cu-2Ce alloy, and aims to solve the problem that copper interference exists when the cerium content in the Al-4Cu-2Ce alloy is determined by adopting a chemical titration method under the condition of lack of equipment such as a spectrograph at present. The method comprises the following steps: dissolving an Al-4Cu-2Ce alloy sample by using dilute sulphuric acid, filtering out insoluble copper, oxidizing cerium into tetravalent cerium by using ammonium persulfate, titrating by using an ammonium ferrous sulfate solution, and determining the content of the Cu4Cu-2Ce alloy sample in the presence of a phenanthroline oxidation-reduction indicator. The percentage content of cerium in the alloy sample is calculated and measured by using the volume number of the consumed ammonium ferrous sulfate standard solution, so that the copper interference phenomenon in the traditional cerium content measurement is effectively avoided, and the detection efficiency of factory inspection of the Ce content in the Al-4Cu-2Ce alloy is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy chemical composition detection, and in particular to a method for determining Ce in an Al-4Cu-2Ce alloy. Background Art

[0002] With the rapid development of modern industry, high-performance alloy materials are increasingly being used in aerospace, automotive, electronics, and other fields. Al-4Cu-2Ce alloy, as a key aluminum alloy, has attracted considerable attention due to its excellent comprehensive properties. Cerium (Ce) plays a key role in Al-4Cu-2Ce alloy. An appropriate amount of Ce can refine the alloy grains, significantly improving its strength, hardness, and heat resistance, while also enhancing its corrosion resistance and processing properties. However, variations in Ce content are highly sensitive to alloy properties. Low Ce content cannot fully exert its beneficial effects, while high Ce content can lead to deterioration of alloy properties. Therefore, accurate determination of Ce content in Al-4Cu-2Ce alloy is crucial for alloy composition control, quality monitoring, and performance optimization. Existing spectroscopic analysis methods, while simple and sensitive, are expensive. Chemical titration methods for cerium in aluminum alloys use hydrochloric acid or sodium hydroxide to dissolve the sample, but high copper content significantly interferes with the titration of Ce. Summary of the Invention

[0003] The present invention provides a method for determining Ce in an Al-4Cu-2Ce alloy, so as to solve the problem that copper interference is easily generated when the cerium content in the Al-4Cu-2Ce alloy is determined by a chemical titration method in the absence of equipment such as a spectrometer.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for determining Ce in an Al-4Cu-2Ce alloy comprises the following steps:

[0006] Step 1. Weigh 0.10g-0.30g of Al-4Cu-2Ce alloy sample into a 200mL-300mL wide-mouth beaker, add 20mL-40mL of sulfuric acid solution with a concentration of (1+3), and heat until the sample is completely dissolved, then dilute with 30mL-50mL of water.

[0007] Step 2: Filter the diluted solution obtained in step 1 with filter paper, place the filtrate in a 400mL-500mL conical beaker, wash the beaker with boiling hot water 5-6 times, precipitate 10-12 times, and then discard the precipitate.

[0008] Step 3: dilute the filtrate obtained in step 2 with water to 180 mL-220 mL, add 15 mL-30 mL of ammonium persulfate solution, heat to oxidize the cerium, and boil for 5 min-7 min. When black manganese dioxide precipitates, cool to 50°C-60°C.

[0009] Step 4: Filter the test solution obtained in step 3 with dense filter paper into a 400mL-500mL conical beaker, and then wash the beaker with boiling hot water 5-6 times.

[0010] Step 5: Add 4 mL to 6 mL of concentrated sulfuric acid with a specific gravity of 1.84 and 4 mL to 6 mL of ammonium persulfate to the filtrate obtained in step 4, and heat to oxidize and boil until the test solution emits large bubbles to remove excess ammonium persulfate, then remove and cool to room temperature.

[0011] Step 6: Titrate the solution obtained in step 5 with 0.0125 mol / L sodium arsenite solution until the solution turns yellow. After an excess of 1 mL, add 2-3 drops of o-phenanthroline indicator and titrate with 0.01 mol / L ammonium ferrous sulfate standard solution until the solution turns bright red, which is the end point.

[0012] Step 7: Substitute the volume of the ferrous ammonium sulfate standard solution consumed in step 6 into The percentage of cerium is calculated using the formula, where C is the molar concentration of the ammonium ferrous sulfate standard solution, V is the number of liters of the ammonium ferrous sulfate standard solution consumed during titration, 0.14 is the coefficient for conversion to cerium, and G is the number of grams of the Al-4Cu-2Ce alloy sample weighed.

[0013] Furthermore, the water in steps 1-4 is deionized water, the sulfuric acid in steps 1 and 5, the ammonium persulfate in steps 3 and 5, and the o-phenanthroline in step 6 are of analytical grade, and the sodium arsenite and ammonium ferrous sulfate in step 6 are both of premium grade.

[0014] The present invention has the following beneficial effects:

[0015] The invention utilizes the phenomenon that copper cannot react with dilute sulfuric acid, adopts dilute sulfuric acid instead of hydrochloric acid or sodium hydroxide to dissolve the sample, filters out the undissolved copper, and then uses ammonium persulfate to oxidize cerium into tetravalent cerium. Then, an ammonium ferrous sulfate solution is used, and in the presence of a 1,2-phenanthroline redox indicator, the volume of the consumed ammonium ferrous sulfate standard solution is used to calculate and determine the percentage of cerium in the alloy sample. The invention effectively avoids the copper interference phenomenon in the traditional cerium content determination, and greatly improves the detection efficiency of the Ce content in the Al-4Cu-2Ce alloy in factory inspection.

[0016] The entire analysis process of the present invention is easy to operate and has low analysis cost, and can be widely applied to factories to test the Ce content in Al-4Cu-2Ce alloys. DETAILED DESCRIPTION

[0017] The present invention will be further described below with reference to specific embodiments.

[0018] Example 1

[0019] A method for determining Ce in an Al-4Cu-2Ce alloy comprises the following steps:

[0020] Step 1: Weigh 0.10 g of Al-4Cu-2Ce alloy sample into a 200 mL wide-mouth beaker, add 20 mL of sulfuric acid solution with a concentration of (1+3), heat until the sample is completely dissolved, and then dilute with 30 mL of water.

[0021] Step 2: Filter the diluted solution obtained in step 1 with filter paper, place the filtrate in a 400 mL conical beaker, wash the beaker with boiling hot water 5 times, precipitate 10 times, and then discard the precipitate.

[0022] Step 3: dilute the filtrate obtained in step 2 to 180 mL with water, add 15 mL of ammonium persulfate solution, heat to oxidize the cerium, and boil for 5 minutes. When black manganese dioxide precipitates appear, cool to 50°C.

[0023] Step 4: Filter the test solution obtained in step 3 into a 400 mL conical beaker using dense filter paper, and then wash the beaker five times with boiling hot water.

[0024] Step 5: Add 4 mL of concentrated sulfuric acid with a specific gravity of 1.84 and 4 mL of ammonium persulfate to the filtrate obtained in step 4, and heat and oxidize and boil until the test solution emits large bubbles to remove excess ammonium persulfate, then remove and cool to room temperature.

[0025] Step 6: Titrate the solution obtained in step 5 with 0.0125 mol / L sodium arsenite solution until the solution turns yellow. After a 1 mL excess, add 2 drops of o-phenanthroline indicator and titrate with 0.01 mol / L ammonium ferrous sulfate standard solution until the solution turns bright red, which is the end point.

[0026] Step 7: Substitute the volume of the ferrous ammonium sulfate standard solution consumed in step 6 into The percentage of cerium was calculated using the formula.

[0027] Example 2

[0028] A method for determining Ce in an Al-4Cu-2Ce alloy comprises the following steps:

[0029] Step 1: Weigh 0.20 g of Al-4Cu-2Ce alloy sample into a 250 mL wide-mouth beaker, add 30 mL of sulfuric acid solution with a concentration of (1+3), heat until the sample is completely dissolved, and then dilute with 40 mL of water.

[0030] Step 2: Filter the diluted solution obtained in step 1 with filter paper, place the filtrate in a 450 mL conical beaker, wash the beaker with boiling hot water 5 times, precipitate 10 times, and then discard the precipitate.

[0031] Step 3: dilute the filtrate obtained in step 2 to 200 mL with water, add 20 mL of ammonium persulfate solution, heat to oxidize the cerium, and boil for 6 minutes. When black manganese dioxide precipitates appear, cool to 55°C.

[0032] Step 4: Filter the test solution obtained in step 3 into a 450 mL conical beaker using dense filter paper, and then wash the beaker five times with boiling hot water.

[0033] Step 5: Add 5 mL of concentrated sulfuric acid with a specific gravity of 1.84 and 5 mL of ammonium persulfate to the filtrate obtained in step 4, and heat and oxidize and boil until the test solution emits large bubbles to remove excess ammonium persulfate, then remove and cool to room temperature.

[0034] Step 6: Titrate the solution obtained in step 5 with 0.0125 mol / L sodium arsenite solution until the solution turns yellow. After a 1 mL excess, add 2 drops of o-phenanthroline indicator and titrate with 0.01 mol / L ammonium ferrous sulfate standard solution until the solution turns bright red, which is the end point.

[0035] Step 7: Substitute the volume of the ferrous ammonium sulfate standard solution consumed in step 6 into The percentage of cerium was calculated using the formula.

[0036] Example 3

[0037] A method for determining Ce in an Al-4Cu-2Ce alloy comprises the following steps:

[0038] Step 1: Weigh 0.30 g of Al-4Cu-2Ce alloy sample into a 300 mL wide-mouth beaker, add 40 mL of sulfuric acid solution with a concentration of (1+3), heat until the sample is completely dissolved, and then dilute with 50 mL of water.

[0039] Step 2: Filter the diluted solution obtained in step 1 with filter paper, place the filtrate in a 500 mL conical beaker, wash the beaker with boiling hot water 6 times, precipitate 12 times, and then discard the precipitate.

[0040] Step 3: dilute the filtrate obtained in step 2 to 220 mL with water, add 30 mL of ammonium persulfate solution, heat to oxidize the cerium, and boil for 7 minutes. When black manganese dioxide precipitates appear, cool to 60°C.

[0041] Step 4: Filter the test solution obtained in step 3 into a 500 mL conical beaker using dense filter paper, and then wash the beaker with boiling hot water 6 times.

[0042] Step 5: Add 6 mL of concentrated sulfuric acid with a specific gravity of 1.84 and 6 mL of ammonium persulfate to the filtrate obtained in step 4, and heat and oxidize and boil until the test solution emits large bubbles to remove excess ammonium persulfate, then remove and cool to room temperature.

[0043] Step 6: Titrate the solution obtained in step 5 with 0.0125 mol / L sodium arsenite solution until the solution turns yellow. After an excess of 1 mL, add 3 drops of o-phenanthroline indicator and titrate with 0.01 mol / L ammonium ferrous sulfate standard solution until the solution turns bright red, which is the end point.

[0044] Step 7: Substitute the volume of the ferrous ammonium sulfate standard solution consumed in step 6 into The percentage of cerium was calculated using the formula.

[0045] (1) Repeatability test

[0046] Al-4Cu-2Ce alloy was drilled, and 11 treated samples were randomly weighed and measured according to the above method. The cerium content determination results and relative standard deviation (RSD) are shown in Table 1:

[0047] Table 1 Repeatability test results

[0048]

[0049] As shown in Table 1, the standard deviation of the cerium content determination results in the Al-4Cu-2Ce alloy is 0.015, and the relative standard deviation (RSD) is 0.77%, which meets the requirement of RSD ≤ 2% for parallel samples in routine laboratory tests. This shows that the determination results of this method are accurate, reliable, and highly reproducible.

[0050] 2. Accuracy test

[0051] Five samples of the prepared Al-4Cu-2Ce alloy were randomly selected and measured according to the above method. The measured values were compared with the measured values provided by the raw material manufacturer. The comparison results are shown in Table 2:

[0052] Table 2 Comparison of the measured values of this method and the measured values provided by the raw material factory

[0053] Sample number This method determines the cerium content value / % Cerium content value measured by raw material factory / % Difference / % 12 1.94 1.96 0.02 13 2.0 1.97 0.03 14 1.98 2.1 0.03 15 1.96 2.0 0.04 16 1.95 1.98 0.02

[0054] As shown in Table 2, the results measured by this method are within 0.05% of the values provided by the raw material manufacturer, indicating that the results of this method are highly accurate and meet the test requirements.

[0055] 3. Comparative test

[0056] Five prepared Al-4Cu-2Ce alloy samples were randomly selected and measured using the method of the present invention and inductively coupled plasma emission spectrometry, respectively, and then compared. The comparison results are shown in Table 3:

[0057] Table 3 Comparison of the results of this method and inductively coupled plasma optical emission spectrometry

[0058]

[0059] As shown in Table 3, the results obtained by this method are within 0.05% of the values obtained by inductively coupled plasma optical emission spectrometry, indicating that the results obtained by this method are highly accurate, meet the test requirements, and are suitable for testing in the absence of equipment such as a spectrometer.

Claims

1. A method for determining Ce in an Al-4Cu-2Ce alloy, characterized in that: The following steps are involved: Step 1. Weigh 0.10g-0.30g of Al-4Cu-2Ce alloy sample into a 200mL-300mL wide-mouth beaker, add 20mL-40mL of sulfuric acid solution with a concentration of (1+3), heat until the sample is completely dissolved, and then dilute with 30mL-50mL of water; Step 2: Filter the diluted solution obtained in step 1 with filter paper, place the filtrate in a 400mL-500mL conical beaker, wash the beaker 5-6 times with boiling hot water, precipitate 10-12 times, and then discard the precipitate; Step 3: dilute the filtrate obtained in step 2 with water to 180 mL-220 mL, add 15 mL-30 mL of ammonium persulfate solution, heat to oxidize the cerium, and boil for 5 min-7 min. When black manganese dioxide precipitates, cool to 50°C-60°C; Step 4: Filter the test solution obtained in step 3 through dense filter paper into a 400mL-500mL conical beaker, and then wash the beaker with boiling hot water 5-6 times; Step 5: Add 4 mL to 6 mL of concentrated sulfuric acid with a specific gravity of 1.84 and 4 mL to 6 mL of ammonium persulfate to the filtrate obtained in step 4, and heat and oxidize and boil until the test solution emits large bubbles to remove excess ammonium persulfate, then remove and cool to room temperature; Step 6: Titrate the solution obtained in step 5 with 0.0125 mol / L sodium arsenite solution until the solution turns yellow. After an excess of 1 mL, add 2-3 drops of o-phenanthroline indicator and titrate with 0.01 mol / L ammonium ferrous sulfate standard solution until the solution turns bright red, which is the end point. Step 7: Substitute the volume of the ferrous ammonium sulfate standard solution consumed in step 6 into The percentage of cerium is calculated using the formula, where C is the molar concentration of the ammonium ferrous sulfate standard solution, V is the number of liters of the ammonium ferrous sulfate standard solution consumed during titration, 0.14 is the coefficient for conversion to cerium, and G is the number of grams of the Al-4Cu-2Ce alloy sample weighed.

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