GOST 25599.3-83

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  ГОСТ 25599.3-83

GOST 25599.3−83 (ST SEV 2950−81) sintered hard Alloys. Methods for the determination of titanium (with Change No. 1)

GOST 25599.3−83
(CT CMEA 2950−81)

Group B59

STATE STANDARD OF THE USSR

SINTERED HARD ALLOYS

Methods for determination of titanium

Sintered hardmetals. Methods for the determination of titanium

OKP 19 6100

Date of introduction 1984−01−01

Resolution of the USSR State Committee on standards of January 20, 1983 N 291 validity period is set with 01.01.84 to 01.01.89*
______________
* Expiration removed by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS No. 5/6, 1993). — Note the manufacturer’s database.

REPRINTING. August 1984

The Change N 1, approved and introduced with effect from 01.01.89 by the resolution of Gosstandart of the USSR from 27.04.88 No. 1184

Change No. 1 made by the manufacturer of the database in the text ICS N 7, 1988


This standard specifies methods for the determination of titanium: photocolorimetric for the mass concentration of from 1% to 20% and differential photocolorimetric for the mass concentration of from 10 to 40% in hard sintered alloy, carbide carbide mixtures and complex carbides.

The standard fully complies ST SEV 2950−81.

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 14339.0−82.

2. PHOTOCOLORIMETRIC METHOD

2.1. The essence of the method

The method is based on formation of colored complex compounds of titanium with hydrogen peroxide in sulfuric acid medium and measuring the optical density of the solution at a wavelength of from 400 to 434 nm.

2.2. Apparatus, reagents and solutions

Spectrophotometer or photocolorimeter with all accessories.

Sulfuric acid GOST 4204−77, density 1.84 g/cmand a solution of 1:4 and 5%.

Tartaric acid according to GOST 5817−77, 30% solution.

Ammonium sulfate according to GOST 3769−78.

Hydrogen peroxide according to GOST 10929−76, 30% solution.

Titanium dioxide or titanium metal.

The solutions of titanium are standard.

Ammonium fluoride, acidic, GOST 9546−75.

Solution a: 0,1668 g pre-calcined to constant weight of titanium dioxide dissolved in a mixture of 20 cmof sulfuric acid and 5 g of ammonium sulfate when heated. The solution after cooling was transferred into a measuring flask with a capacity of 100 cm, a dilute sulfuric acid solution (1:4) to the mark and mix, or 0.1 g of metallic titanium is dissolved in 20 cmof sulfuric acid and 5 g of ammonium sulfate on the open tiles in the heat-resistant beaker covered with watch glass. After cooling, the solution is transferred to a volumetric flask with a capacity of 100 cm, a dilute sulfuric acid solution (1:4) to the mark and mix.

1 cmof the solution contains 0.001 g of titanium.

Solution B: in a volumetric flask with a capacity of 100 cmis taken as 10 cmof solution A, made up to the mark with water and mix.

1 cmof a solution contains 0.0001 g of titanium.

The type of analytical scale VLR-200 or any other type providing a weighing error of no more than ±0,0002 g.

(Changed edition, Rev. N

1).

2.3. Analysis

2.3.1. A sample weighing 0.1 g were placed in a glass, add from 5 to 10 cmof sulfuric acid and 5 g of ammonium sulfate.

Beaker cover watch glass, and dissolve the sample under intense heat.

After cooling in a glass poured 30 cmof a solution of tartaric acid. Then the sample solution was transferred to volumetric flask with a capacity of 100 cm, is diluted to the mark with water and mix.

Depending on the expected content of titanium in a volumetric flask with a capacity of 100 cmaliquote selected part of the sample solution in accordance with the table.1, and then injected 1 cmof hydrogen peroxide solution, dilute to the mark 5% solution of sulfuric acid and stirred. If the solution is cloudy, then the solution is filtered through a dry filter into a dry beaker.

Table 1

Optical density of the solution is measured at a wavelength of 400 nm, using a cuvette with thickness of the absorbing layer is 50 mm or at a wavelength of 434 nm using the cuvette with the thickness of the absorbing layer of 10 mm Solution comparison is the solution, not containing hydrogen peroxide.

Mass fraction of titanium find for the calibration schedule.

(Changed edition, Rev. N 1).

2.3.2. Construction of calibration curve

When building a calibration curve for the cell with thickness of the absorbing layer of 10 mm in seven volumetric flasks with a capacity of 100 cmis taken 1,0; 2,0; 3,0; 4,0; 5,0; 6,0 and 7.0 cmof standard titanium solution And pour 5 cmof sulphuric acid 1 cmof hydrogen peroxide solution, dilute to the mark with water and mix. The optical density of colored solutions are measured at a wavelength of 434 nm.

When building a calibration curve for the cell with a thickness of the light absorbing layer 50 mm in ten volumetric flasks with a capacity of 100 cmis taken 1,0; 2,0; 3,0; 4,0; 5,0; 6,0; 7,0; 8,0; 9,0 and 10.0 cmof a standard solution of titanium is Used, pour 5 cmof sulphuric acid 1 cmof hydrogen peroxide solution, dilute to the mark with water and mix. The optical density of colored solutions are measured at a wavelength of 400 nm.

As a solution comparison solution is used in the reference experiment on the content of titanium in the reactants.

According to the obtained values of optical densities and their corresponding grades of titanium to build a calibration curve

I.

2.3.3. When the analyzed sample contains the vanadium from the solution prepared for measurement of optical density, a leak of 30 cmand transferred to a volumetric flask with a capacity of 50 cm, add 0.1 g of acidic ammonium fluoride. After 3 min measure the optical density-painted in vanadium solution and subtract it from the optical density of Ti+V previously measured.

2.4. Processing of the results

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

,

where is the mass of titanium in aliquote part of the analyzed solution found by the calibration schedule g;

 — the total volume of the analyzed solution, cm;

 — weight of sample, g;

 — volume aliquote part of the solution, cm.

Note. 1% of molybdenum corresponds to 0.08% of titanium, therefore, if the analyzed sample contains molybdenum, this value is subtracted from the mass fraction of titanium, calculated by the formula.

2.4.2. Permissible differences between results of parallel measurements at a confidence level =0.95 does not exceed the values specified in table.2.

Table 2

3. DIFFERENTIAL PHOTOCOLORIMETRIC METHOD

3.1. The essence of the method

The method is based on formation of colored complex compounds of titanium with hydrogen peroxide in sulfuric acid medium followed by determination of titanium by the method of differential photocalorimetry.

3.2. Apparatus, reagents and solutions

Apparatus in accordance with claim 2.2.

Reagents and solutions — p. 2.2 and reference solution.

Reference solution is prepared before the analysis: in a volumetric flask with a capacity of 100 cmselect 5 or 8 cmof a standard solution of titanium And injected 5% solution of sulfuric acid to 90 cm, 1 cmof hydrogen peroxide solution, dilute to the mark with the same solution of sulfuric acid and stirred.

3.3. Analysis

3.3.1. Depending on the titanium content of take the weight and mass in accordance with table.3 and dissolved according to claim 2.3.1.

Table 3

To the cooled solution poured 1 cmof hydrogen peroxide solution, poured into a volumetric flask with a capacity of 100 cm, is diluted to the mark with water and mix. To determine the content of titanium in a volumetric flask with a capacity of 100 cmaliquote selected part of the analyzed solution in accordance with the table.3 injected 5% solution of sulfuric acid to 90 cm, 1 cmof hydrogen peroxide solution, dilute to the mark with the same solution of sulfuric acid and stirred.

The optical density of colored solution is measured at a wavelength of 490 nm using a cuvette and a solution of comparison in accordance with the table.3.

The titanium content found by the calibration schedule.

3.3.2. Construction of calibration curve

When building a calibration curve for the cell with thickness of the absorbing layer is 50 mm in seven volumetric flasks with a capacity of 100 cmis taken 8,0; 9,0; 10,0; 11,0; 12,0; 13,0 and 14.0 cmstandard solution of titanium And poured 5% solution of sulfuric acid to 90 cm, 1 cmof hydrogen peroxide solution, dilute to the mark with the same solution of sulfuric acid and stirred.

The optical density measured at a wavelength of 490 nm. The comparison solution is a solution containing 0.008 g of titanium.

When building a calibration curve for the cell with thickness of the absorbing layer 30 mm in eight volumetric flasks with a capacity of 100 cmis taken 5,0; 6,0; 7,0; 8,0; 9,0; 10,0; 11,0; 12,0 cmstandard solution of titanium and then do as above.

The optical density measured at a wavelength of 490 nm.

The comparison solution is a solution containing 0.005 g of titanium.

According to the obtained values of optical densities and their corresponding grades of titanium to build the calibration graph.

3.3.3. In the presence in the sample of vanadium analysis is carried out as specified in clause 2.3.3.

3.4. Processing of the results

3.4.1. Mass fraction of titanium is calculated according to claim 2.4.1.

3.4.2. Permissible differences between results of parallel measurements at a confidence level =0.95 does not exceed the values specified in table.4.

Table 4