GOST 3240.1-76
GOST 3240.1−76 magnesium Alloys. Methods for determination of aluminium (with Change No. 1)
GOST 3240.1−76
Group B59
INTERSTATE STANDARD
MAGNESIUM ALLOYS
Methods for determination of aluminium
Magnesium alloys.
Methods for determination of aluminium
ISS 77.120.20
AXTU 1709
Date of introduction 1978−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of aviation industry of the USSR
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
3. REPLACE GOST 3240−56 in part of sec. V*
________________
Probably a mistake of the original. Should read: part II section. — Note the manufacturer’s database.
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
The number of the paragraph, subparagraph |
| GOST 8.315−97 |
2.5, 3.6 |
| GOST 61−75 |
2.2, 3.2 |
| GOST 199−78 |
2.2 |
| GOST 804−93 |
3.2, 4.2 |
| GOST 3117−78 |
2.2, 3.2 |
| GOST 3118−77 |
2.2, 3.2, 4.2 |
| GOST 3240.0−76 |
1.1 |
| GOST 3640−94 |
2.2 |
| GOST 3760−79 |
2.2, 3.2 |
| GOST 4461−77 |
2.2, 4.2 |
| GOST 4517−87 |
3.2 |
| GOST 4919.1−77 |
2.2 |
| GOST 5457−75 |
4.2 |
| GOST 5823−78 |
2.2 |
| GOST 5962−67 |
3.2 |
| GOST 10652−73 |
2.2, 3.2 |
| GOST 11069−2001 |
3.2, 4.2 |
| GOST 25086−87 |
2.5, 3.6 |
5. Limitation of actions taken by Protocol No. 2−92 of the Interstate Council for standardization, Metrology and certification (ICS 2−93)
6. EDITION with Change No. 1, approved in June 1987 (IUS 11−87)
1. This standard specifies the titrimetric and atomic absorption methods for the determination of aluminum (with a mass fraction of aluminum from 0.5 to 12%) and photometric method for the determination of aluminum (with a mass fraction of aluminum from 0.003 to 0.4%).
(Changed edition, Rev. N 1).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 3240.0.
2. TITRIMETRIC METHOD FOR DETERMINATION OF ALUMINIUM CONTENT
2.1. The essence of the method
The method is based on the isolation of aluminium from solution by the addition of benzoate of ammonium. After dissolving the precipitate in hydrochloric acid aluminium bind when heated with a solution of disodium salt of ethylenediaminetetraacetic acid (Trilon B), which added in excess. The surplus of the solution Trilon B octarepeat solution of zinc acetate at a pH of 5,5−5,8, using as indicator kylinalove orange.
(Changed edition, Rev. N 1).
2.2. Reagents and solutions
Hydrochloric acid according to GOST 3118 and the solution, diluted 1:1.
Nitric acid according to GOST 4461.
Ammonia water according to GOST 3760 and the solution, diluted 1:5.
Sodium acetate according to GOST 199, 50% solution.
Ammonium acetate according to GOST 3117.
Glacial acetic acid according to GOST 61.
A buffer solution with a pH of 5.8; prepared as follows: 500 g of ammonium acetate dissolved in 1000 cmof water and add 20 cm
of acetic acid.
Ammonium benzoate, 10 and 0.5% solutions.
Methyl orange (indicator), 0,1% solution; prepared and stored according to GOST 4919.1.
Selenology orange, 0,1% solution; prepared and stored according to GOST 4919.1.
Zinc GOST 3640.
Salt is the disodium Ethylenediamine — N, N, N', N'- tetraoxane acid, 2-water (Trilon B) according to GOST 10652, 0.05 M solution: 18,613 g Trilon B dissolved in 600 cmof water, transferred to a volumetric flask with a capacity of 1 DM
, dilute to the mark with water and mix. The titer of the solution Trilon B is determined as follows: 1 g of zinc is dissolved in 50 cm
of hydrochloric acid 1:1, transferred to a volumetric flask with a capacity of 1 DM
, dilute to the mark with water and mix. 1 cm
of the solution contains 0.001 g of zinc.
10 cmof this solution was transferred by pipette into the conical flask with a capacity of 250 cm
, dilute with water to 100 cm
, is administered 1−2 drops of methyl orange solution and neutralize with ammonia until yellow. The flask poured 20 cm
of buffer solution and titrated with a solution of Trilon B using kylinalove orange until the color of the solution from red to yellow.
The titer of the solution Trilon B (T), expressed in g/cmof aluminum, calculated according to the formula
where — the weight of zinc taken for the installation of the titer, g;
— volume of solution Trilon B, used for titration, cm
;
2,423 — the ratio of zinc to aluminum.
Zinc acetate, 2-water according to GOST 5823, solution with molar concentration of 0.05 mol/DM: 10,95 g of zinc acetate dissolved in 100 cm
of water, add 2 cm
of acetic acid and diluted to 1 DM
with water.
The ratio of the solution Trilon B solution and acetate of zinc is set as follows: in a conical flask with a capacity of 250 cmtaken 10 cm
of the solution Trilon B and diluted with water to 100−150 cm
. The solution is neutralized with ammonia, diluted 1:5, color yellow, methyl orange, add 20 cm
buffer solution, a few drops of indicator and titrate with a solution of acetate of zinc to pink color.
The ratio of the concentrations of the solution Trilon B solution and a solution of zinc acetate () are calculated according to the formula
where — volume of solution Trilon B taken for titration, cm
;
— the volume of solution of acetate of zinc, consumed in the titration of Trilon B solution, see
.
(Changed edition, Rev. N 1).
2.3. Analysis
The weight of alloy taken in accordance with the content of aluminum in the amount indicated in the table.1.
Table 1
| Mass fraction of aluminum, % |
The weight of the portion of the alloy, g |
| From 0.5 to 2.0 |
1,0 |
| SV. 2,0 «4,0 |
0,5 |
| «4,0» 8,0 |
0,25 |
| «8,0» 10,0 |
0,2 |
| «10,0» 12,0 |
0,1 |
The sample is placed in a beaker with a capacity of 400 cm, add 20 cm
of water and small portions of 20 cm
of hydrochloric acid diluted 1:1. After the dissolution a few drops of nitric acid and boil to remove oxides of nitrogen.
The cooled solution is neutralized with ammonia before the formation of turbidity, which is dissolved with a few drops of hydrochloric acid diluted 1:1, pour 5 cmof a solution of sodium acetate and carefully neutralized with a solution on paper «Congo» hydrochloric acid diluted 1:1 until the color of the paper «the Congo» from red to purple.
To the solution add 25 cmof a 10% solution of benzoate of ammonia, dilute with hot water up to 300 cm
, stirred with a glass rod and heated to boiling.
After the sediment is removed from the glass plate, leave for 10−15 minutes in a warm place and filtered on a double filter of medium density.
The beaker and precipitate was washed 6−8 times with 0.5% sodium benzoate of ammonium. The precipitate is washed with hot water in the same Cup, where he carried out the dissolution of the sample, then the filter is washed with 25 cmof hot hydrochloric acid and 5−6 times with hot water. The solution is heated to complete dissolution of the precipitate, evaporated to a volume of 100 cm
and add a solution of Trilon B of 20−25 cm
. The solution was then heated to boiling, neutralize with ammonia until yellow color methyl orange, add 20 cm
buffer solution, cool, add 5−7 drops of orange kylinalove and titrated with a solution of acetate of zinc to pink color.
(Changed edition, Rev. N
1).
2.4. Processing of the results
2.4.1. Mass fraction of aluminium () in percent is calculated by the formula
where — volume of solution Trilon B added to the subject solution, cm
;
— the amount of zinc acetate solution consumed for titration of the excess of the solution Trilon B, cm
;
— the ratio of the concentrations of the solution Trilon B, and solution of acetate of zinc;
the titer of the solution Trilon B, expressed in g/cm
of aluminum;
— the weight of the portion,
G.
2.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.2.
Table 2
| Mass fraction of aluminum, % |
The absolute allowable difference, % |
| From 0.5 to 1.5 |
0,05 |
| SV. 1,5 «4,0 |
0,15 |
| «4,0» 8,0 |
0,2 |
| An «8.0 «to 12.0 |
0,3 |
2.5 accuracy Control measurements
To control the accuracy of measuring the mass fraction of aluminum from 0.5 to 12% use the national standard samples, industry-standard samples and standard samples of the enterprise, issued in accordance with GOST 8.315.
Accuracy control measurement is carried out in accordance with GOST 25086.
Allowed to control the accuracy of measuring the mass fraction of aluminum using the addition method.
(Added, Rev. N 1).
3. PHOTOCOLORIMETRIC METHOD FOR DETERMINATION OF ALUMINIUM CONTENT
3.1. The essence of the method
The method is based on the formation of the aluminum eryhromycin complex compounds at pH of 5.8, painted in crimson red color. Colored solution photometered at
(Changed edition, Rev. N 1).
3.2. Apparatus, reagents and solutions
Spectrophotometer type SF-4A or photocolorimeter type FEK-56, or FEK 60.
Hydrochloric acid according to GOST 3118, distilled, solutions diluted 1:1 and 1:5.
Ammonia water according to GOST 3760, solution diluted 1:5.
Ascorbic acid, 2% freshly prepared solution.
Eryhromycin , 0,05% solution; prepared as follows: 0.1 g of erioglaucine
dissolved in 195 cm
of water with the addition of 5 cm
of acetic acid.
Ammonium acetate according to GOST 3117.
Glacial acetic acid according to GOST 61.
A buffer solution with a pH of 5.8: 500 g ammonium acetate and dissolve in 1 DMof water and poured 20 cm
of acetic acid.
The paper «the Congo».
Bidistilled water, obtained according to GOST 4517.
Dishes washed by boiling with hydrochloric acid and double-distilled water.
Fenilalanina acid, 1% solution.
Rectified ethyl alcohol according to GOST 5962*.
________________
* On the territory of the Russian Federation GOST R 51652−2000.
Salt is the disodium Ethylenediamine — N, N, N', N'-tetraoxane acid (Trilon B) according to GOST 10652, solution; is prepared as follows: 1 g Trilon B dissolved in 95 cmof water with the addition of 5 cm
of ethyl alcohol.
Magnesium GOST 804 purity not less than 99.9%, containing less than 0.003% of aluminum.
Aluminium GOST 11069 brand А195.
Standard solutions of aluminium.
Solution A, prepared as follows: 0.1 g of aluminium is dissolved in 50 cmof hydrochloric acid diluted 1:1. The solution is transferred into a measuring flask with volume capacity of 1000 cm
, is added to the mark with water and mix.
1 cmof solution A contains 0.1 mg of aluminium.
Solution B is prepared as follows: 5 cmmortar And transferred to a volumetric flask with a capacity of 500 cm
, add 5 cm
of hydrochloric acid diluted 1:1, and adjusted to the mark with water.
1 cmof the solution contains 0.001 mg of aluminium.
(Amended And
ZM. N 1).
3.3. Analysis
3.3.1. (Deleted, Rev. N 1).
3.3.2. Analysis in the absence of zirconium and beryllium
The weight of the alloy 0.1 g dissolved in 10 cmof hydrochloric acid diluted 1:1. The solution was transferred to a volumetric flask with a capacity of 100 cm
.
When the mass fraction of aluminium in the alloy to 0,009% photometered the entire solution. When the mass fraction of aluminum in the alloy is in excess of 0.009% select aliquote parts listed in the table.3, of the volumetric flask with a capacity of 100 cm, which is topped up to the mark with water and mix. Pour 20−30cm
of water, neutralized with ammonia solution on the paper «the Congo» to dark-purple color.
Table 3
| Mass fraction of aluminum, % |
The volume aliquote part of the solution, cm |
| From 0.003 to 0,009 |
The entire solution |
| SV. 0,009 «0,04 |
20 |
| «Of 0.04» to 0.2 |
5 |
| «0,2» 0,4 |
2 |
To the neutralized solution, add with a pipette 2 cmof ascorbic acid, 2cm
of eryhromycin
and allowed to stand for 15 min. Then add a 10 cm
buffer solution, made up to the mark with water and mix.
After 15 min measure the optical density of colored solutions at 
(Changed edition, Rev. N 1).
3.3.3. Analysis in the presence of zirconium
0.5 g sample is dissolved by heating in 15 cmof hydrochloric acid diluted 1:1, and add 50 cm
of hot water. The solution was transferred to a volumetric flask with a capacity of 200 cm
, add 5 cm
phenylarsonic acid for every 1% zirconium in the alloy and the solution gently heated to boiling. The cooled solution was adjusted to the mark with water, mixed and filtered.
Depending on the mass fraction of aluminum in the alloy is taken aliquote part of the solution, the specified table.4.
Table 4
| Mass fraction of aluminum, % |
The volume aliquote part of the solution, cm |
| From 0.003 to 0,009 |
25 |
| SV. 0,009 «0,04 |
10 |
| «Of 0.04» to 0.20 |
2 |
| «0,20» 0,4 |
1 |
Aliquot part of the solution is placed in a flask with a capacity of 100 cm, top up with water to 30 cm
, neutralized with ammonia solution on the paper «the Congo» to dark-purple color and further analysis are as indicated in claim
(Changed edition, Rev. N 1).
3.3.4. Analysis in the presence of beryllium
For each definition, take two aliquote part of the solution, prepared as specified in clause of the solution Trilon B, is neutralized with ammonia according to the paper «the Congo» to dark-purple color and further analysis are as indicated in claim 3.3.2, then measure the optical density. Solution comparison is the solution of the reference experiment with the addition of 5 cm
of a solution of Trilon B.
(Changed edition, Rev. N 1).
3.4. In six volumetric flasks with a capacity of 100 cmpoured in 30 cm
water, 10 cm
of hydrochloric acid diluted 1:5, and add standard solution B 0; 2,0; 3,0; 5,0; 7,0 and 10,0 cm
, which corresponds to 0; 2·10
; 3·10
; 5·10
; 7·10
and 1·10
g of aluminum. The solutions are boiled, cooled, carry out the neutralization on the paper «the Congo» to dark-purple color and then add all reagents as indicated in claim
(Changed edition, Rev. N
1).
3.5. Processing of the results
3.5.1. Mass fraction of aluminium () in percent is calculated by the formula
where the amount of aluminum found in the calibration schedule g;
— volume of initial solution, cm
;
— volume aliquote part of the solution, cm
;
— the weight of the portion of alloy,
3.5.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.5.
Table 5
| Mass fraction of aluminum, % |
The absolute allowable difference, % |
| From 0.003 to 0.01 |
0,001 |
| SV. Is 0.01 «to 0.03 |
0,004 |
| «To 0.03» to 0.09 |
0,01 |
| «0,09» 0,20 |
0,02 |
| «Of 0.20» to 0.40 |
0,03 |
3.6. Control of measurement accuracy
To control the accuracy of measuring the mass fraction of aluminum from 0.003 to 0.4% using the state standard samples, industry-standard samples and standard samples of the enterprise of magnesium alloys, issued in accordance with GOST 8.315. Accuracy control measurement is carried out in accordance with GOST 25086.
Allowed to control the correctness of the results of determination of aluminium using addition method.
(Added, Rev. N 1).
4. ATOMIC ABSORPTION METHOD FOR DETERMINATION OF ALUMINIUM CONTENT
4.1. The essence of the method
The method is based on dissolving the samples in hydrochloric acid in the presence of nitric acid and subsequent measurement of the atomic absorption of aluminum at a wavelength of 309,3 nm in a flame acetylene — nitrous oxide. Height fotometricheskogo phase 2, see Components of magnesium alloys, and impurity interference analysis have not, however, to identify the conditions of spraying being analyzed, and the calibration solutions should approximate the adjustment of the acid content, as well as the basics of the alloy in the calibration and sample solutions.
(Changed edition, Rev. N 1).
4.2. Apparatus, reagents and solutions
Spectrophotometer atomic absorption.
Hydrochloric acid according to GOST 3118 distilled, density 1.12 g/cm.
Nitric acid according to GOST 4461.
Acetylene in cylinders GOST 5457.
Nitrous oxide cylinders medical.
Potassium chloride according to the NTD, 10% solution.
Primary magnesium ingots according to GOST 804 in the form of chips.
A solution of magnesium 50 g/DM: 50 g of magnesium carefully dissolved in 800 cm
of hydrochloric acid of 1:1. The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM
, made up to the mark and mix.
Primary aluminium GOST 11069, grade A 99.
Standard aluminium solution: 1 g of metallic aluminium is dissolved in 50 cmof hydrochloric acid of 1:1. The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM
, made up to the mark with water and mix.
1 cmof the solution contains 1 mg of aluminium
.
4.3. Analysis
4.3.1. A sample of alloy weighing 0.2 g were placed in a glass with a capacity of 100 cmand dissolved in 15 cm.
of hydrochloric acid 1:1 followed by oxidation of 5−10 drops of nitric acid. The solution was boiled to remove oxides of nitrogen, cooled, transferred to a volumetric flask with a capacity of 100 cm
, add 5 cm
of potassium chloride solution, made up to the mark with water and mix.
Parallel to the sample conduct analysis of control experience.
Measure the atomic absorption of aluminum in the sample solution, the solution control experience and solutions to build the calibration curve in atomic absorption spectrophotometer relative to distilled water at a wavelength of 309,3 nm in a flame acetylene — nitrous oxide.
The concentration of aluminium in the sample solution and the reference experiment is determined by the calibration schedule.
4.3.2. Construction of calibration curve
In a series of volumetric flasks with a capacity of 100 cmis administered at 4 cm
of a solution of magnesium 5 cm
of potassium chloride solution, and 0; 0,5; 1,0; 2,0; 4,0; 6,0; 8,0; 10,0 and 12.0 cm
standard solution of aluminium, which corresponds to 0; 0,5; 1,0; 2,0; 4,0; 6,0; 8,0; 10,0 and 12.0 mg of aluminum, made up to the mark with water, mix and measure the atomic absorption of aluminum according to claim
From the obtained values of atomic absorption solutions containing a standard solution, subtract the value of atomic absorption of a solution containing a standard solution, and the obtained values of atomic absorption and their corresponding grades of aluminium to build the calibration graph.
4.4. Processing of the results
4.4.1. Mass fraction of aluminium () in percent is calculated by the formula
where is the mass of aluminium in the sample solution found by the calibration schedule g;
— the mass of the aluminium in solution in the reference experiment, was found in the calibration schedule g;
— the weight of the portion of sample taken for spectrophotometry,
4.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.6.
Table 6
| Mass fraction of aluminum, % |
The absolute allowable difference, % |
| From 1.0 to 2.0 |
0,05 |
| SV. The 2.0 «and 6.0 |
0,07 |
| «A 6.0» to 12.0 |
0,3 |
(Changed edition, Rev. N 1).
4.5. Control of measurement accuracy
4.5.1. Control the accuracy of measuring the mass fraction of aluminum is carried out according to claim 2.5.
(Added, Rev. N 1).
