GOST 25278.3-82
GOST 25278.3−82 Alloys and alloys of rare metals. Method for the determination of hafnium (Change No. 1)
GOST 25278.3−82
Group B59
STATE STANDARD OF THE USSR
ALLOYS AND ALLOYS OF RARE METALS
Method for the determination of hafnium
Alloys and foundry alloys of rare metals. Method for determination of hafnium
AXTU 1709
Valid from 01.07.83
to 01.07.93*
_______________________________
* Expiration removed
according to the Protocol of the Intergovernmental Council
for standardization, Metrology and certification
(IUS N 2, 1993). — Note the manufacturer’s database.
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
PERFORMERS
Yu. A. Karpov, E. G. Nembrini, V. G., Miscreants, G. N. Andrianov, E. S. Danilin, M. A. Desyatkova L. I. Kirsanova, T. M. Malyutina, Y. F. Markov, V. M. Mikhailov, L. A. Nikitina, L. G. Obruchkova, N. Rasnitsyn, N. Suvorova, L. N. Filimonov
2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from
3. The period of examination — 1993
The frequency of inspection is 5 years.
4. INTRODUCED FOR THE FIRST TIME.
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
The designation of the reference document referenced |
Section number, paragraph |
GOST 3758−78 |
2 |
GOST 4204−77 |
2 |
GOST 7172−76 | 2 |
GOST 10652−73 |
2 |
GOST 10929−76 |
2 |
GOST 26473.0−85 |
1.1 |
6. Validity extended until
7. REPRINT (November 1988) with amendment No. 1, approved in October 1987 (ICS 1−88).
This standard sets the photometric method for determining the hafnium:
from 1 to 10% in alloys (ligatures) based on tantalum (components: tungsten-30% rhenium, not more than 15%);
from 1 to 3% in alloys (ligatures) based on yttrium.
The method is based on formation of colored complex compounds of hafnium with selenology orange in sulfuric acid 0.2 mol/DMsolution. Hydrolysis of tantalum (- based alloy) prevent the introduction of hydrogen peroxide. Absorption of complexes of tantalum, tungsten with selenology orange take into account, by measuring the total absorption of complexes of tantalum, tungsten and hafnium relative to the other equal aliquots of the sample in which it is added Trilon B, masking only the hafnium. The definition does not interfere up to 2 mg of tungsten, up to 10 mg of rhenium and yttrium in fotometriya solution.
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis and security requirements — according to GOST 26473.0−85.
(Changed edition, Rev. N 1).
2. APPARATUS, REAGENTS AND SOLUTIONS
Brand photoelectrocolorimeter FEK-56 or similar device.
Tile electric.
Muffle furnace with thermostat providing temperatures up to 1000 °C.
Analytical scale.
Libra technical.
Volumetric flasks with a capacity of 50, 100 and 200 cm.
Pipettes without division into 1, 2, 5 and 10 cm.
Microburette with a capacity of 5 cm.
The chemical glasses with a capacity of 100 cm.
Watch-glasses.
The quartz crucibles high capacity of 40 cm.
Ammonium sulfate according to GOST 3758−75*.
_______________
* Consistent with the original. — Note the manufacturer’s database.
Potassium preservatory according to GOST 7172−76.
Sulfuric acid GOST 4204−77 and diluted 1:3 and a solution of 0.5 mol/DM.
Hydrogen peroxide according to GOST 10929−76.
Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid, 2-water (Trilon B) according to GOST 10652−73, solution 0,05 mol/l; prepared as follows: 18.6 g Trilon B dissolved in water with heating (if the solution is turbid, it is filtered), transferred to a volumetric flask with a capacity of 1 DM, is cooled and adjusted to the mark with water.
Selenology orange, an aqueous solution of 1 mg/cm.
Hafnium metal containing at least 99.9% of hafnium in the form of a powder or fine shavings.
Standard solution hafnium (spare) containing 1 mg/cmof hafnium: 0.1 g of hafnium metal is placed in a heat resistant beaker and dissolved by heating in 3 cmof concentrated sulfuric acid in the presence of 0.3 g of ammonium sulfate. M, obtained after complete dissolution of the metal, dissolved in water; the clear solution was transferred to volumetric flask with a capacity of 100 cmand adjusted to the mark with water (the acidity of final solution ~0.5 mol/lfor sulphuric acid).
The working solution of hafnium containing 10 µg/cmof hafnium, prepared on the day of use by dilution of a standard solution sulfuric acid 0.5 mol/DM100 times.
(Changed edition, Rev. N 1).
3. ANALYSIS
3.1. A portion of the sample weight of 0.1 g in the form of powder or slices, placed in a quartz crucible, add 2−4 g of persulfate potassium, a few drops of concentrated sulphuric acid and fused in a muffle at a temperature of 800−900 °C to obtain a homogeneous melt.
In the case of alloys based on tantalum, the melt is dissolved in a crucible under low heat in a mixture consisting of 6 cmof sulphuric acid (1:3) and 1 cmof hydrogen peroxide. The hot clear solution was transferred to volumetric flask with a capacity of 250 cm, which had previously poured a mixture of 25 cmof sulphuric acid (1:3) and 1cmof hydrogen peroxide, adjusted to the mark with water, mixed (solution a steady 7−8 PM, followed by hydrolysis). The expected mass fraction of hafnium over 4% solution is diluted one more time: take 10 cmof solution in a volumetric flask with a capacity of 100 cmand adjusted to the mark with sulphuric acid of 0.5 mol/DM(additional dilution must be considered when processing the results).
In the case of alloys based on yttrium — V is dissolved in a crucible with a weak heating in sulfuric acid 0.5 mol/DM. The hot clear solution was transferred to volumetric flask with a capacity of 250 cm, cooled, adjusted to the mark with sulphuric acid of 0.5 mol/DM.
For the determination of hafnium in two volumetric flasks with a capacity of 50 cmis taken equal aliquote part of the solution (5, 10 or 20 cm), containing 20−60 mg of hafnium, diluted to 20 cmof sulphuric acid 0.5 mol/DM. In one of the flasks is introduced 0.2 cmof the solution Trilon B, mix. Then both flasks poured on 2.5 cmmortar kylinalove orange, bring to the mark with water and mix. After 30 min measure the optical density of a solution containing Trilon B, relative to solution of Trilon B in the photoelectrocolorimeter at 540 nm in a cuvette with the thickness of the light absorbing layer 30 mm.
A lot of find hafnium for the calibration
WMD graphics.
3.2. Construction of calibration curve
In a volumetric flask with a capacity of 50 cmis injected from microburette from 0.0 to 7.0 cmworking solution of hafnium with an interval of 1 cm. To all flasks add up to 20 cmof sulphuric acid 0.5 mol/DMat 2.5 cmkylinalove orange solution, stirring after each addition of reagent, adjusted to the mark with water and mix again. In one of the flasks poured all reagents with the exception of hafnium (zero solution). After 30 minutes (colored solutions are stable for 7−8 HR) measure the optical density of solutions on the photoelectrocolorimeter at 540 nm in a cuvette with the thickness of the light absorbing layer 30 mm in relation to the zero solution. According to the obtained results build a calibration curve in the coordinates: the optical density is the mass of hafnium. Separate test points of the graph along with the analysis of samples.
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of hafnium () in percent is calculated by the formula
,
where is the mass of hafnium found in the calibration graphics mg;
the capacity of volumetric flasks at the first dilution, cm;
— aliquotes volume of the solution taken for dilution, cm;
the capacity of the volumetric flask for the second dilution, cm;
— aliquotes volume of the solution taken for the determining, cm;
— the weight of the portion of the sample,
G.
4.2. Discrepancies between the results of two parallel determinations and the results of the two tests should not exceed the values of permissible differences given in the table.
Mass fraction of hafnium, % |
The allowable divergence, % |
1,0 |
0,2 |
3,0 |
0,4 |
5,0 |
0,6 |
10,0 |
1,1 |
(Changed edition, Rev. N 1).