GOST 6689.24-92

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  ГОСТ 6689.24-92

GOST 6689.24−92 Nickel, alloys Nickel and copper-Nickel. Method of determination of calcium

GOST 6689.24−92

Group B59

STATE STANDARD OF THE USSR

NICKEL, ALLOYS NICKEL AND COPPER-NICKEL

Method of determination of calcium

Nickel, nickel and copper-nickel alloys. Method for the determination of calcium

AXTU 1709

Date of introduction 1993−01−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of metallurgy of the USSR

DEVELOPERS

V. N. Fedorov, Y. M. Leybov, Boris Krasnov, A. N. Bulanova, L. V. Morea, A. I. Vorobyov

2. APPROVED AND promulgated by the Decree of Committee of standardization and Metrology of the USSR from 18.02.92 N 167

3. INTRODUCED FOR THE FIRST TIME

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

_______________
* Probably a mistake of the original. Should read GOST 6689.1−92. — Note the manufacturer’s database.

This standard establishes the atomic absorption method for the determination of calcium (when calcium mass fraction from 0.03 to 0.2%) in Nickel alloys according to GOST 19241.

1. GENERAL REQUIREMENTS

General requirements for methods of analysis GOST 25086 with the addition of sec. 1 GOST 6689.1.

2. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF CALCIUM

2.1. The essence of the method

The method is based on measuring the absorption of light by atoms of calcium, formed during the introduction of the analyzed solution in the flame acetylene-air.

2.2. Equipment, reagents, solutions

Atomic absorption spectrometer with a radiation source for calcium.

Nitric acid according to GOST 4461, diluted 1:1 and 1:3.

Calcium carbonate according to GOST 4530.

Standard calcium solution: 0.25 g of calcium carbonate (previously dried to constant mass at 100−105 °C) are dissolved in 20 cmof nitric acid (1:3). The solution was transferred to a volumetric flask with a capacity of 1 DMand topped to the mark with water.

1 cmof the solution contains 0.0001 g of calcium.

2.3. Analysis

2.3.1. A sample of alloy weighing 0.2 g was dissolved with heating in 10 cmof nitric acid (1:1). The solution was transferred to a volumetric flask with a capacity of 100 cmand top up with water to the mark. At the same time spend control experience.

Measure the atomic absorption of calcium in the flame of acetylene-air at a wavelength 422,7 nm parallel to the calibration solutions.

2.3.2. Construction of calibration curve

Five volumetric flasks with a capacity of 100 cmis placed 0,6; 1,0; 2,0; 3,0 and 4,0 cmstandard solution of calcium, which corresponds to 0,06; 0,1; 0,2; 0,3 and 0,4 mg of calcium and topped to the mark with water. Measure the atomic absorption of calcium, as mentioned in paragraph 2.3.1. According to the obtained results build a calibration curve.

2.4. Processing of the results

2.4.1. Mass fraction of calcium () in percent is calculated by the formula

,

where is the concentration of calcium in the sample solution alloy, was found in the calibration schedule, g/cm;

the concentration of calcium in solution in the reference experiment, was found in the calibration schedule, g/cm;

 — the volume of the sample solution, cm;

 — weight of sample, g

.

2.4.2. Discrepancies in the results of three parallel measurements (rate of convergence) and the results of the two tests (index of reproducibility) shall not exceed the values of permissible differences given in the table.

2.4.3. Control of accuracy of analysis results is carried out by additives in accordance with GOST 25086.