GOST 6674.5-96

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  ГОСТ 6674.5-96

GOST 6674.5−96 copper phosphorous Alloys. Method for determination of iron

GOST 6674.5−95

Group B59

INTERSTATE STANDARD

COPPER PHOSPHOROUS ALLOYS

Methods of iron determination

Copper-phosphorous alloys. Methods for determination of iron

ISS 77.120.30
AXTU 1709

Date of introduction 2001−07−01

Preface

1 DEVELOPED by the Interstate technical Committee for standardization MTK 107, Donetsk state Institute of non-ferrous metals (Danism)

SUBMITTED to the State Committee of Ukraine for standardization, Metrology and certification (Protocol No. 10 dated 3 October 1996)

2 ADOPTED by the Interstate Council for standardization, Metrology and certification (Protocol No. 10 dated 3 October 1996)

The adoption voted:

3 Resolution of the State Committee of the Russian Federation for standardization and Metrology dated December 19, 2000 N 384-St inter-state standard GOST 6674.5−96 introduced directly as state standard of the Russian Federation from July 1, 2001

4 INTRODUCED FOR THE FIRST TIME

1 Scope

This standard specifies atomic absorption when the iron content from 0.05% to 0.2% and the photometric at an iron content of from 0.01% to 0.5% methods for determination of iron in copper-phosphorous alloys.

2 Normative references

The present standard features references to the following standards:

The Copper GOST 859−78. Brand

GOST 3118−77 hydrochloric Acid. Specifications

GOST 4204−77 sulfuric Acid. Specifications

GOST 4461−77 nitric Acid. Specifications

GOST 5457−75 Acetylene, dissolved and gaseous. Specifications

GOST 6344−73 Thiourea. Specifications

GOST 6674.0−96 copper phosphorous Alloys. General requirements for methods of analysis

GOST 10484−78 hydrofluoric Acid. Specifications

GOST 10929−76 Hydrogen peroxide. Specifications

GOST 13610−79 carbonyl Iron radio. Specifications

3 General requirements

General requirements for methods of analysis GOST 6674.0.

4 Photometric method

4.1 the essence of the method

The method is based on formation of colored complex solution of iron (II) with 1,10-phenanthroline at a pH of 1.6−1.8 in the presence of thiourea and measuring the optical density of the solution.

4.2 Equipment, reagents and solutions

Photoelectrocolorimeter or spectrophotometer.

Nitric acid according to GOST 4461 and diluted 1:1, solutions of 0.2 mol/land 1 mol/DM.

Sulfuric acid according to GOST 4204, diluted 1:4, solutions of 0.2 mol/land 1 mol/DM.

Hydrochloric acid according to GOST 3118.

Hydrofluoric acid according to GOST 10484.

Hydrogen peroxide according to GOST 10929.

Thiourea according to GOST 6344, solution 100 g/DM.

1,10-fenantrolin hydrochloric acid or 1,10-fenantrolin sulfate according to the current normative document, a solution of 30 g/DM.

Radio engineering carbonyl iron according to GOST 13610.

Standard solutions of iron.

Solution a: 0.5 g of iron dissolved in 20 cmof hydrochloric acid with addition of hydrogen peroxide, the solution was boiled to destroy excess hydrogen peroxide, cooled, transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.001 g of iron.

Solution B: 5 cmmortar And transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water, mix, use freshly prepared.

1 cmstandard solution B contains 0,00005 g of iron.

Solution: 2 cmstandard solution And transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water, mix, use freshly prepared.

1 cmof the solution contains 0,00002 g of iron.

Copper metal according to GOST 859.

Standard copper solution: 1 g of copper metal is dissolved in 20 cmof nitric acid (1:1), the solution is evaporated to wet condition salts, add 20 cmof a solution of nitric or sulfuric acid (1 mol/DM) (depending on the composition of the analyzed alloy), cooled, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water, mix.

1 cmof the solution contains 0.01 g of copper.

4.3 analysis

4.3.1 For alloys containing less than 0.1% silicon: a portion of the alloy in accordance with table 1 were placed in a glass with a capacity of 250 cmand dissolved by heating in 15 cmof hydrochloric acid and 2 cmof nitric acid.


Table 1

The solution is evaporated to dryness, the dry residue add 20 cmof nitric acid (1 mol/DM) heat until complete dissolution of the residue is cooled, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

Aliquot part of the solution in accordance with table 1 was placed in a volumetric flask with a capacity of 50 cm, add 15 cmof water, 10 cmof a solution of thiourea, 2 cmof a solution of 1,10-fenantrolina, after 30 min, top up to the mark with water and measure the optical density of the solution at a wavelength of 490 nm. As a comparison, using a solution not containing iron solution in which the amount of copper and all of the reagents corresponds to aliquote part of the analyzed solution.

4.3.2 For alloys containing more than 0.1% silicon, a portion of the alloy in accordance with table 1 were placed in a glass with a capacity of 250 cmand dissolved by heating in 15 cmof hydrochloric acid, 2cmof nitric acid with the addition of 2−3 drops of hydrofluoric acid. Add 5 cmof sulfuric acid solution (1:4), the solution is evaporated until the appearance of sulphuric acid fumes, cool, add 20 cmof water, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix. Then do as specified in 4.3.1.

4.3.3 For constructing a calibration curve for the mass concentration of iron is from 0.01% to 0.05% in volumetric flasks with a capacity of 50 cmis placed 10 cmto the standard solution of copper, prepared similarly to the sample, 0; 0,5; 1,0; 1,5; 2,0; 3,0 cmstandard solution of iron, add 15 cmof water, 10 cmof a solution of thiourea, 2 cmof a solution of 1,10-fenantrolina. Then do as specified in 4.3.1.

According to the obtained values of optical density and corresponding mass fractions of iron to build the calibration graph.

4.3.4 To construct the calibration curve for the mass concentration of iron is from 0.05% to 0.5% in volumetric flasks with a capacity of 50 cmis placed 2.5 cmstandard solution of copper, prepared similarly to the sample, 0; 0,25; 0,5; 1,0; 2,0; 3,0 cmstandard solution of iron, add 2.5 cmof solutions of nitric or sulfuric acid concentration of 0.2 mol/DM(depending on the composition of test alloy). Then do as specified in 4.3.1.

According to the obtained values of optical density and corresponding mass fractions of iron to build the calibration graph.

4.4 Processing of results

4.4.1 Mass fraction of iron , %, is calculated by the formula

, (1)

where is the mass of iron was found in the calibration schedule g;

the sample mass of alloy, suitable aliquote part of the solution,

4.4.2 discrepancies in the results of parallel measurements and the results of the analysis shall not exceed allowable (at confidence probability of 0.95) of the values given in table 2.


Table 2

Percentage

5 Atomic absorption method

5.1 the essence of the method

The method is based on dissolving samples of the alloy in a mixture of hydrochloric and nitric acids and measuring the nuclear absorption of iron at a wavelength of 248.3 nm in a flame air-acetylene.

5.2 the Instrument, reagents and solutions

Atomic absorption spectrophotometer.

Acetylene according to GOST 5457.

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

Hydrochloric acid according to GOST 3118.

A mixture of hydrochloric and nitric acids is prepared as follows: one volume of nitric acid mixed with three volumes of hydrochloric acid.

Radio engineering carbonyl iron according to GOST 13610.

Standard solutions of iron.

Solution a: 1 g of iron is dissolved in 80 cmof nitric acid (1:1), cooled, transferred to a volumetric flask with a capacity of 1 DM, adjusted to the mark with water and mix.

1 cmof the solution contains 0.001 g of iron.

Solution B: 25 cmsolution And placed in a volumetric flask with a capacity of 250 cm, the volume was adjusted solution in the flask to the mark with water and mix.

1 cmof a solution contains 0.0001 g of iron.

5.3 analysis

5.3.1 a sample of alloy weighing 0.25 g was dissolved in 20 cmof a mixture of acid, boil to remove oxides of nitrogen. The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix.

5.3.2 For the construction of calibration curve six volumetric flasks with a capacity of 100 cmeach placed 0; 1,0; 2,0; 3,0; 4,0 and 5,0 cmof standard iron solution B is introduced into each flask 15 cmof the mixture of acids, add water and mix thoroughly.

Solution not containing iron, is used for the reference experiment.

5.3.3 Solutions of the samples in the reference experiment and the solutions for constructing the calibration curve is sprayed in air-acetylene flame and measure the atomic size of iron absorption at a wavelength of 248.3 nm.

According to the obtained results build a calibration curve in the coordinates: «weight of iron, g — value of atomic absorption».

Weight of iron in the sample solution and the reference experiment is determined by the calibration schedule.

5.4 processing of the results

5.4.1 Mass fraction of iron , %, is calculated by the formula

, (2)

where is the mass of iron in the sample solution found by the calibration schedule g;

 — the mass of iron in solution in the reference experiment, was found in the calibration schedule g;

 — the weight of the portion of alloy,

5.4.2 Differences of the results of parallel measurements and the results of the analysis shall not exceed allowable (at confidence probability of 0.95) of the values given in table 2.

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UDC 669.35'779:546.72.06:006.354 ISS 77.120.30 B59 AXTU 1709

Key words: copper phosphorous alloys, iron, photometric method, 1,10-fenantrolin, atomic absorption method, wavelength