GOST 3240.13-76

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  ГОСТ 3240.13-76

GOST 3240.13−76 magnesium Alloys. Method for the determination of sodium (Change No. 1)

GOST 3240.13−76

Group B59

INTERSTATE STANDARD

MAGNESIUM ALLOYS

Method for the determination of sodium

Magnesium alloys.
Method for determination of sodium

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 28.12.76 N 2889

3. INTRODUCED FOR THE FIRST TIME

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

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)


This standard sets flame photometric method for the determination of sodium (with a mass fraction of sodium from 0.001 to 0.05%).

The method is based on measuring the intensity of the resonance doublet of sodium 589,0−589,6 nm excited in acetylene-air flame. Height fotometricheskogo phase 1 see To eliminate the effect of partial blanking radiation of sodium in the presence of the alloy base and the acids used for sample digestion, the latter in the respective amounts administered in the calibration solutions.

In the analysis of alloys containing lithium, the lithium calibration curve is introduced in the amount corresponding to its mass fraction in the analyzed samples.

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 3240.0.

2. APPARATUS, REAGENTS AND SOLUTIONS

The fiery photometer or spectrophotometer.

Acetylene in cylinders GOST 5457.

Bidistilled water, obtained according to GOST 4517.

Hydrochloric acid of high purity according to GOST 14261, diluted 1:1.

Nitric acid of high purity according to GOST 11125, diluted 1:1.

Primary magnesium ingots according to GOST 804 in the form of chips.

A solution of magnesium 50 g/DM: 50 g of magnesium was dissolved in 800 cmof hydrochloric acid, the solution transferred to a volumetric flask with a capacity of 1 DM, dilute to the mark with water and mix.

Sodium chloride, 0,1 M (0,1 n) standard-titer (fixanal).

Standard solutions of sodium

Solution a: 0.1 M solution of sodium chloride fiksanala transferred to a volumetric flask with a capacity of 1 DM, dilute to the mark with water and mix.

1 cmof solution A contains 0,0023 g of sodium.

Solution B: 43.5 cmsolution And transferred to a volumetric flask with a capacity of 1 DM, dilute to the mark with water and mix.

1 cmof a solution contains 0.0001 g of sodium.

Lithium carbonate, H. h

A solution of lithium 10 mg/cm: 53,245 g previously dried at 100−105 °C to constant weight of lithium carbonate is placed in a tall glass with a capacity of 700−800 cm, moistened with water and gradually pour a solution of hydrochloric acid to enlightenment solution. After dissolution the solution was transferred to volumetric flask with a capacity of 1 DM, dilute to the mark with water and mix.

(Changed edition, Rev. N 1).

3. ANALYSIS

3.1. A portion of the alloy with a mass of 2 g is placed in a heat-resistant beaker or conical flask with a capacity of 300−400 cmand dissolved in 30 cmof hydrochloric acid. In the presence of the copper alloy, it is transferred to the solution by adding a few drops of nitric acid. The resulting solution was transferred to a volumetric flask with a capacity of 100 cm.

The vessel, which was carried out dissolving, rinse with two portions of double-distilled water and the washings are attached to the main solution. The mixture was diluted with bidistilled water to the mark and mix. The resulting solution was introduced into the atomizer of the photometer and record the magnitude of the issue. All take readings at a strictly constant pressure of acetylene and air. The slope of the calibration curve periodically, every four samples, to check by repeating the photometry data of one of the previously analyzed solutions. When you change the readings the results of the analysis of the previous four samples of void and fotometricheskie of these solutions repeat. Are parallel to the control experience.

3.2. Construction of calibration curve

In seven volumetric flasks with a capacity of 100 cmis administered at 40 cmof a solution of magnesium (the analysis of alloys, doped with lithium, lithium solution is injected, the amount of which is calculated by the formula where is the mass fraction of lithium in the sample, %), add 0; 0,2; 0,4; 1,0; 2,0; 4,0 and 10.0 cmof a solution of sodium, which corresponds to 0; 0,02; 0,04; 0,10; 0,20; 0,40; 1,00 mg sodium.

The solutions were diluted to the mark with water, mixed, injected into the atomizer and photometric as specified in claim 3.1. The results of measurements of the intensity of the resonance doublet of sodium build calibration curve.

(Changed edition, Rev. N 1).

4. PROCESSING OF THE RESULTS

4.1. Mass fraction of sodium () in percent is calculated by the formula

,

where is the mass of sodium found on the calibration schedule g;

 — the weight of the portion of alloy,

(Changed edition, Rev. N 1).

4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in the table.

5. CONTROL OF MEASUREMENT ACCURACY

To control the accuracy of measuring the mass fraction of sodium from 0.001 to 0.05% use 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.

Control the accuracy of measuring the mass fraction of sodium may be performed by a method of additives.

Sec. 5. (Added, Rev. N 1).